最近有个练手的小例子，大概就是配置两个数据源，从一个数据源读取数据写到另一个数据源，虽然最后做了出来，但是不支持事务。。。就当是对mybatis-plus/mybatis组件使用方式的记录吧，本次例子使用的仍是mybatis-plus
回忆一下mybatis核心对象：
- Configuration 初始化基础配置，比如MyBatis的别名等，一些重要的类型对象，如，插件，映射器，ObjectFactory和typeHandler对象，MyBatis所有的配置信息都维持在Configuration对象之中
- SqlSessionFactory SqlSession工厂
- SqlSession 作为MyBatis工作的主要顶层API，表示和数据库交互的会话，完成必要数据库增删改查功能
- Executor MyBatis执行器，是MyBatis 调度的核心，负责SQL语句的生成和查询缓存的维护
- StatementHandler 封装了JDBC Statement操作，负责对JDBC statement 的操作，如设置参数、将Statement结果集转换成List集合。
- ParameterHandler 负责对用户传递的参数转换成JDBC Statement 所需要的参数，
- ResultSetHandler 负责将JDBC返回的ResultSet结果集对象转换成List类型的集合；
- TypeHandler 负责java数据类型和jdbc数据类型之间的映射和转换
- MappedStatement MappedStatement维护了一条
- SqlSource 负责根据用户传递的parameterObject，动态地生成SQL语句，将信息封装到BoundSql对象中，并返回
- BoundSql 表示动态生成的SQL语句以及相应的参数信息
组件介绍
拦截器
mybatis可以在执行语句的过程中对特定对象进行拦截调用，主要有四个
- Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed) 处理增删改查
- ParameterHandler (getParameterObject, setParameters) 设置预编译参数
- ResultSetHandler (handleResultSets, handleOutputParameters) 处理结果
- StatementHandler (prepare, parameterize, batch, update, query) 处理sql预编译，设置参数
这四个是可以拦截的对象,大概的做法是实现mybatis拦截器的接口并在上面添加注解来确定拦截那些方法
下面是接口Interceptor所要实现的方法，setPropertites可以用来初始化，而plugin则包装目标对象供拦截器处理，基于动态代理实现，Plugin类是动态代理类，对实现Interceptor的接口的类进行处理，而实现的拦截器会被加入到拦截器链进行处理
Object intercept(Invocation var1) throws Throwable;
default Object plugin(Object target) {
return Plugin.wrap(target, this);
}
default void setProperties(Properties properties) {
}
plugin.warp方法
拦截器链：
public class InterceptorChain {
private final List interceptors = new ArrayList();
public InterceptorChain() {
}
public Object pluginAll(Object target) {
Interceptor interceptor;
for(Iterator var2 = this.interceptors.iterator(); var2.hasNext(); target = interceptor.plugin(target)) {
interceptor = (Interceptor)var2.next();
}
return target;
}
public void addInterceptor(Interceptor interceptor) {
this.interceptors.add(interceptor);
}
public List getInterceptors() {
return Collections.unmodifiableList(this.interceptors);
}
}
并在handler里面添加这些拦截器类，执行pluginAll方法，返回一个经过代理链处理的对象
实现该接口以后，要添加注解来表明拦截哪些方法，方法则是上面四个对象的拥有的方法。下面这个注解则是指定了拦截哪些对象的哪个方法，args则是被拦截方法的参数
public @interface Signature {
Class type();
String method();
Class[] args();
}
比如这个例子
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
Signature注解就对应上面的接口、方法及其参数，然后在拦截器添加一个@Intercepts，这个注解的内容是Signature注解数组
有了拦截器，初步想法是根据方法拦截，如果select则使用读数据源，增删改则使用写数据源，这个其实原理和之前写的一篇代码级别读写分离很相似，也是通过ThreadLocal存放当前线程的数据源，然后通过拦截器来判断用哪个数据源，交由AbstarctRoutingDataSource来根据ThreadLoacl里面的值来处理。
但是有个问题，两个数据源转换，表名、字段名不一定相等，比如从pgsql的一个叫user_info表里的数据转到mysql叫user表的数据，字段名都不相同
我的处理方法是查询对象的目标的字段名为准，然后给每个字段一个注解指向修改对象的数据源表字段名，如果查询目标表没有插入目标表的字段，便在select的时候默认select null或者用代码限定查询的字段。这里首先先定义了三个注解，分别对应查、改相应的数据源、表名、字段
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface TranDB {
DBType from();
DBType to();
Class object();
}
public @interface TranField {
String from() default "";
String to();
String empty = "null";
}
public @interface TranTable {
String from();
String to();
}
User类
@TranTable(from = "user_info", to = "user")
public class User {
@TranField(to = "id")
@TableId
private Integer userId;
@TranField(to = "wx_nickname")
private String userAccount;
@TranField(to = "roles")
private String mobile;
@TranField(from=TranField.empty,to="create_time")
private Date createTime;
@TranField(from=TranField.empty,to="update_time")
private Date updateTime;
@TranField(from=TranField.empty,to="bonus")
private Integer bonus;
@TranField(to="wx_id")
private String[] test;
}
UserMapper
@TranDB(from = DBType.PGSQL,to=DBType.MYSQL,object=User.class) public interface UserMapper extends BaseMapper{ }
这里添加一个缓存mapper信息类，方便在拦截器中调用，其中有个成员变量是用来存储mapperName对应的TranDB注解信息，拦截器通过拦截的方法获取mapper名称，再通过这个mapper信息类获取他的TranDB注解，这个注解里面有对应的实体class，可以用来获取字段信息注解及表名信息注解，而另一个成员变量则是用来存放待会说到的表名替换，这里面实现了两个接口，一个通过spring容器加载资源的接口，另一个则是用来初始化bean的。
package com.trendy.task.transport.config;
import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.handler.SelfTableNameHandler;
import com.trendy.task.transport.util.CamelHumpUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternUtils;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import java.util.*;
/**
* Mapper信息缓存类
*/
public class MapperAuxFeatureMap implements ResourceLoaderAware, InitializingBean {
private static ResourceLoader resourceLoader;
@Value("${tran.mapperlocation}")
public String MAPPER_LOCATION ;
public static final String TABLEPREFIX="t_";
//表名处理
public Map tableNameHandlerMap;
//mapper文件的注解
public Map mapperTranDbMap;
//通过方法获取mapper名称
public static String getMapperNameFromMethodName(String source){
int end = source.lastIndexOf(".") + 1;
String mapper = source.substring(0, end - 1);
mapper = mapper.substring(mapper.lastIndexOf(".") + 1);
return mapper;
}
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
MapperAuxFeatureMap.resourceLoader=resourceLoader;
}
@Override
public void afterPropertiesSet() throws Exception {
ResourcePatternResolver resolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
MetadataReaderFactory metaReader = new CachingMetadataReaderFactory(resourceLoader);
Resource[] resources = resolver.getResources("classpath*:"+MAPPER_LOCATION.replace(".","/")+"/**/*.class");
mapperTranDbMap = new HashMap<>();
tableNameHandlerMap = new HashMap<>();
for (Resource r : resources) {
MetadataReader reader = metaReader.getMetadataReader(r);
String className = reader.getClassMetadata().getClassName();
Class c = Class.forName(className);
if (c.isAnnotationPresent(TranDB.class)) {
String name = c.getSimpleName();
TranDB tranDB = c.getAnnotation(TranDB.class);
mapperTranDbMap.put(name, tranDB);
String value = tranDB.object().getSimpleName();
tableNameHandlerMap.put(TABLEPREFIX+ CamelHumpUtils.humpToLine(value),new SelfTableNameHandler(tranDB.object()));
}
}
}
}
替换数据源的部分代码，对query和update（即增删改）方法进行拦截，改方法使用mysql数据源，查方法使用pgsql数据源
package com.trendy.task.transport.dyma;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.config.MapperAuxFeatureMap;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.util.Properties;
/**
* @author: lele
* @date: 2019/10/23 下午4:24
*/
@Intercepts({
@Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class})
})
public class DynamicDataSourceInterceptor implements Interceptor {
private MapperAuxFeatureMap mapperAuxFeatureMap;
public DynamicDataSourceInterceptor(MapperAuxFeatureMap mapperAuxFeatureMap) {
this.mapperAuxFeatureMap = mapperAuxFeatureMap;
}
@Override
public Object intercept(Invocation invocation) throws Throwable {
//如果读取数据，使用From的库，否则使用To库
DBType db =null;
Object[] objects = invocation.getArgs();
MappedStatement statement = (MappedStatement) objects[0];
String mapper = MapperAuxFeatureMap.getMapperNameFromMethodName(statement.getId());
TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapper);
if (statement.getSqlCommandType().equals(SqlCommandType.SELECT)) {
db = tranDB.from();
} else {
db = tranDB.to();
}
DynamicDataSourceHolder.setDbType(db);
return invocation.proceed();
}
@Override
public Object plugin(Object o) {
if (o instanceof Executor) {
return Plugin.wrap(o, this);
} else {
return o;
}
}
@Override
public void setProperties(Properties properties) {
}
}
然后对字段进行修改的拦截器，这里为什么要继承AbstactSqlPaserHandler呢，因为可以复用他的方法，以及为后来加入表名替换的类做准备，这里的流程是获取原来字段的名字，并改为TranField的to所存储的内容
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.core.toolkit.PluginUtils;
import com.baomidou.mybatisplus.extension.handlers.AbstractSqlParserHandler;
import com.trendy.task.transport.annotations.TranDB;
import com.trendy.task.transport.annotations.TranField;
import com.trendy.task.transport.config.MapperAuxFeatureMap;
import com.trendy.task.transport.util.CamelHumpUtils;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
/**
* @author: lele
* @date: 2019/10/23 下午5:12
*/
@Intercepts({
@Signature(
type = StatementHandler.class,
method = "prepare",
args = {Connection.class, Integer.class}
),
@Signature(
type = StatementHandler.class,
method = "update",
args = {Statement.class}
),
@Signature(
type = StatementHandler.class,
method = "batch",
args = {Statement.class}
)
})
public class FieldHandler extends AbstractSqlParserHandler implements Interceptor {
private MapperAuxFeatureMap mapperAuxFeatureMap;
public FieldHandler(MapperAuxFeatureMap mapperAuxFeatureMap) {
this.mapperAuxFeatureMap = mapperAuxFeatureMap;
}
@Override
public Object plugin(Object target) {
return target instanceof StatementHandler ? Plugin.wrap(target, this) : target;
}
@Override
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = PluginUtils.realTarget(invocation.getTarget());
MetaObject metaObject = SystemMetaObject.forObject(statementHandler);
super.sqlParser(metaObject);
MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");
BoundSql boundSql = (BoundSql) metaObject.getValue("delegate.boundSql");
Boolean select = mappedStatement.getSqlCommandType().equals(SqlCommandType.SELECT);
if (!select) {
//通过获取mapper名称从缓存类中获取对应的注解
String mapperName = MapperAuxFeatureMap.getMapperNameFromMethodName(mappedStatement.getId());
TranDB tranDB = mapperAuxFeatureMap.mapperTranDbMap.get(mapperName);
//获取类的所有属性
Class clazz = tranDB.object();
Map mapField = new HashMap<>(clazz.getFields().length);
while (!clazz.equals(Object.class)) {
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
mapField.put(field.getName(), field);
}
clazz = clazz.getSuperclass();
}
//替换sql
String sql = boundSql.getSql();
for (Map.Entry entry : mapField.entrySet()) {
String sqlFieldName = CamelHumpUtils.humpToLine(entry.getKey());
if (sql.contains(sqlFieldName)) {
String from = entry.getValue().getAnnotation(TranField.class).to();
sql = sql.replaceAll(sqlFieldName, from);
}
}
metaObject.setValue("delegate.boundSql.sql", sql);
}
return invocation.proceed();
}
}
现在还有一个问题要处理，就是表名替换，但是这个有个小坑，这个功能也相当于上面替换sql的功能比如insert into user(user_info,user_id) values ...,比如把user这个表名替换为user_info这个表来执行，此时的插入语句会把所有user的替换成user_info,这时候官方的建议是用@TableName这个注解更改表名避免出现这个情况
表名处理器
使用：实现ITableNameHandler，并实现接口方法返回一个表名字
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.extension.parsers.ITableNameHandler;
import com.trendy.task.transport.annotations.TranTable;
import org.apache.ibatis.reflection.MetaObject;
/**
* @author: lele
* @date: 2019/10/24 下午2:39
* 表名替换的handler
*/
public class SelfTableNameHandler implements ITableNameHandler {
private final Class clazz;
public SelfTableNameHandler(Class clazz) {
this.clazz = clazz;
}
@Override
public String dynamicTableName(MetaObject metaObject, String sql, String tableName) {
TranTable t = (TranTable) clazz.getAnnotation(TranTable.class);
if (sql.toLowerCase().startsWith("select")) {
return t.from();
} else {
return t.to();
}
}
}
也可以注入到mp自带的分页那个拦截器中
@Bean
public FieldHandler fieldHandler() {
FieldHandler f = new FieldHandler(mapperAuxFeatureMap());
DynamicTableNameParser t = new DynamicTableNameParser();
t.setTableNameHandlerMap(mapperAuxFeatureMap().tableNameHandlerMap);
f.setSqlParserList(Collections.singletonList(t));
return f;
}
字段填充器
mysql的表里有创建时间、修改时间、积分，对于这些字段，而pgsql表里面没有，这时候想在插入时使用一个默认的值，这时候可以使用字段填充器
做法：实现MetaObjectHandler接口，并重写里面的方法，然后在字段的@TableField的fill类型里面说明需要填充时情况
例子，对createTime，updateTime，bouns进行默认填充，使用getFieldValueByName和setFieldValByName方法进行赋值
package com.trendy.task.transport.handler;
import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import java.util.Date;
/**
* @author lulu
* @Date 2019/10/24 23:15
* 自动填充的handler
*/
public class DefaultFieldValueHandler implements MetaObjectHandler {
public static final String CREATETIME = "createTime";
public static final String UPDATETIME = "updateTime";
public static final String BOUNS = "bonus";
private void handle(String name, MetaObject metaObject, Object target) {
Object o = getFieldValByName(name, metaObject);
if (o == null) {
setFieldValByName(name, target, metaObject);
}
}
@Override
public void insertFill(MetaObject metaObject) {
handle(CREATETIME, metaObject, new Date());
handle(UPDATETIME, metaObject, new Date());
handle(BOUNS, metaObject, 500);
}
@Override
public void updateFill(MetaObject metaObject) {
handle(UPDATETIME, metaObject, new Date());
}
}
然后为user添加注解@TableField的注解
@TranField(from=TranField.empty,to="create_time")
@TableField(fill = FieldFill.INSERT)
private Date createTime;
@TranField(from=TranField.empty,to="update_time")
@TableField(fill = FieldFill.INSERT_UPDATE)
private Date updateTime;
@TranField(from=TranField.empty,to="bonus")
@TableField(fill= FieldFill.INSERT)
private Integer bonus;
然后在全局配置中加入这个字段填充器类
@Bean
public GlobalConfig globalConfig() {
GlobalConfig globalConfig = new GlobalConfig();
globalConfig.setBanner(false);
globalConfig.setMetaObjectHandler(defaultFieldValueHandler());
return globalConfig;
}
工厂类配置上全局配置 sqlSessionFactory.setGlobalConfig(globalConfig());
类型处理器
类型处理器，用于 JavaType 与 JdbcType 之间的转换，用于 PreparedStatement 设置参数值和从 ResultSet 或 CallableStatement 中取出一个值，比如把String、Integer、Long、Double放到数据库里面用逗号分隔形式存储，此时可以
自定义类型处理器，这里针对上面四个对象数组实现类型转换处理，setxxx方法主要是对参数进行处理，然后把处理后的结果放入数据库中，而get方法则处理从数据库取出来的数据该如何处理，这里接受一个lambda函数作为方法转换，即字符串-》目标类型，这里定义一个抽象类统一处理方法，然后具体转换方法由子类实现
package com.trendy.task.transport.handler;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.function.Function;
/**
* @author lulu
* @Date 2019/10/25 21:46
*/
//@MappedJdbcTypes({})表明处理哪种jdbc类型
@MappedTypes(Object[].class)//表明处理哪种javatype
public abstract class AbstractArrayTypeHandler extends BaseTypeHandler {
//这里接受一个lambdah函数做转换处理
private final Function method;
public AbstractArrayTypeHandler(Function method){
this.method=method;
}
@Override
public void setNonNullParameter(PreparedStatement preparedStatement, int i, Object[] objects, JdbcType jdbcType) throws SQLException {
StringBuilder sb=new StringBuilder();
for(Object o:objects){
sb.append(o.toString()+",");
}
sb.deleteCharAt(sb.length()-1);
preparedStatement.setString(i,sb.toString());
}
@Override
public T[] getNullableResult(ResultSet resultSet, String s) throws SQLException {
return getArray(resultSet.getString(s));
}
@Override
public T[] getNullableResult(ResultSet resultSet, int i) throws SQLException {
return getArray(resultSet.getString(i));
}
@Override
public Object[] getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
return getArray(callableStatement.getString(i));
}
protected T[] getArray(String source){
if(source==null){
return null;
}
String[] resString=source.split(",");
if(this.method==null){
return (T[])resString;
}
T[] resArray= (T[]) new Object[resString.length];
for (int i = 0; i < resString.length; i++) {
resArray[i]=method.apply(resString[i]);
}
return resArray;
}
}
然后定义一个工厂存放子类
package com.trendy.task.transport.handler;
import java.util.function.Function;
/**
* @author lulu
* @Date 2019/10/25 22:33
*/
public interface ArrayTypeHandlerFactory {
class IntegerArrayTypeHandler extends AbstractArrayTypeHandler{
public IntegerArrayTypeHandler() {
super(Integer::parseInt);
}
}
class DoubleArrayTypeHandler extends AbstractArrayTypeHandler{
public DoubleArrayTypeHandler(){
super(Double::parseDouble);
}
}
class LongArrayTypeHandler extends AbstractArrayTypeHandler{
public LongArrayTypeHandler(){
super(Long::parseLong);
}
}
class StringArrayTypeHandler extends AbstractArrayTypeHandler{
public StringArrayTypeHandler(){
super(null);
}
}
}
指定处理类型
@TableField(typeHandler = ArrayTypeHandlerFactory.StringArrayTypeHandler.class)
好了，现在来测试下，
@Test
public void selectById() {
List userList = userService.list(new LambdaQueryWrapper().select(User::getUserId,User::getMobile,User::getUserAccount,User::getTest));
userService.saveBatch(userList);
}
大概就到这里，代码完整版的github地址：GitHub - 97lele/transport
但是这个有个缺陷，就是不支持事务，还有saveOrUpdate方法也不支持，因为两个数据源都不一样，他是先查，看是否有再做更新或者插入操作，这些问题仍需解决，且当作一个使用方法记录的小例子吧
补充
mybatis-plus默认的baseMapper不支持批量的插入和更新，有时候会为了这个批量的方法去继承serviceImpl类，而这个类有没有其他的业务代码在里面，继承仅仅是为了获取批量操作的方法，会显得这个类有点”贫血“
对于这种情况，偶然看到一个开源的项目onemall对BaseMapper做了扩展，使它支持了批量插入的做法，在此基础下，我也做了一定的扩展
根据自己的见解，简单描述下流程：
核心就是自定义一个sql自动注入器，mybatis-plus会扫描mapper类 ,为每个mapper类构造一个MappedStatement（相当于mapper里的一个sql）
添加到配置类里面（具体在下面(2)）,只会在初始化时候执行一次，而我们要做的，就是把某个特定mapper，注入我们想要的模板方法
具体注入在MybatisMapperAnnotationBuilder，注入动态sql,getSqlInjector获取sql注入器，并为当前的MapperBuilderAssistant对象(类似于mapper)注入mappedStatement(sql)
（1）注入开始，里面的inspectInject就是
inspectInject就会把abstractMethod一一注入进去
public void inspectInject(MapperBuilderAssistant builderAssistant, Class mapperClass) {
Class modelClass = extractModelClass(mapperClass);
if (modelClass != null) {
String className = mapperClass.toString();
Set mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration());
if (!mapperRegistryCache.contains(className)) {
List methodList = this.getMethodList(mapperClass);
if (CollectionUtils.isNotEmpty(methodList)) {
TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);
// 循环注入自定义方法
methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));
} else {
logger.debug(mapperClass.toString() + ", No effective injection method was found.");
}
mapperRegistryCache.add(className);
}
}
}
（(2)抽象方法注入类,最终放到configuration类缓存，形成一个sql
具体看看AbstractMethod的实现类，而默认的DefaultSqlInject类就有我们baseMapper所包含的默认方法,我们要添加多两个方法，批量更新和批量插入
下面开始编码
首先继承AbstarctMethod类，实现我们想注入的sql模板
对于批量插入，使用 insert into table columns values (values),(values),(values)
对于批量更新，使用 update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;update table set xx=xx,xx=xx where xx=xx;进行分号分割
因为要用到标签解析的功能，需要用script包裹起来。
具体初始化模板如下, 对其进行填充
public enum CustomSqlMethodEnum {
/**
* 批量插入
*/
INSERT_BATCH("insertBatch",
"批量插入",
""),
/**
* 批量更新
*/
UPDATE_BATCH("updateBatchByIds",
"批量更新",
""
),
/**
* 根据联合键查询
*/
SELECT_BY_COMPOSEKEYS("selectByComposeKeys",
"联合主键查询",
""
),
/**
* 根据联合键查询
*/
SELECT_IDS_BY_COMPOSEKEYS("selectIdsByComposeKeys",
"联合主键查询id",
""
),
/**
* 根据联合主键删除
*/
DELETE_BY_COMPOSEKEYS("deleteByComposeKeys",
"联合主键删除",
""
),
/**
* 根据联合主键更新
*/
UPDATE_BY_COMPOSEKEYS("updateByComposeKeys"
, "联合主键批量修改",
""
);
private final String method;
private final String desc;
private final String sql;
CustomSqlMethodEnum(String method, String desc, String sql) {
this.method = method;
this.desc = desc;
this.sql = sql;
}
public String getMethod() {
return method;
}
public String getDesc() {
return desc;
}
public String getSql() {
return sql;
}
}
下面是构造批量插入和更新的代码逻辑
批量插入：主要是构造——表名、插入列、插入值,这里为了防止覆盖数据库默认值，也可以做if test 的那种判空，来取消插入，不过比较麻烦，这里就不做了
public class InsertBatch extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
KeyGenerator keyGenerator = new NoKeyGenerator();
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.INSERT_BATCH;
// ==== 拼接 sql 模板 ==============
StringBuilder columnScriptBuilder = new StringBuilder(LEFT_BRACKET);
StringBuilder valuesScriptBuilder = new StringBuilder(LEFT_BRACKET);
// 主键拼接
if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {
//(x1,x2,x3
columnScriptBuilder.append(tableInfo.getKeyColumn()).append(COMMA);
//(item.xx,item.xx
valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty())).append(COMMA);
}
// 普通字段拼接
List fieldList = tableInfo.getFieldList();
for (TableFieldInfo fieldInfo : fieldList) {
//有更新默认填充器的不参与赋值
if (!fieldInfo.isWithInsertFill() && fieldInfo.isWithUpdateFill()) {
continue;
}
columnScriptBuilder.append(fieldInfo.getColumn()).append(COMMA);
valuesScriptBuilder.append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
// 替换多余的逗号为括号
//(x1,x2)
columnScriptBuilder.setCharAt(columnScriptBuilder.length() - 1, ')');
//(item.xx,item.xx2)
valuesScriptBuilder.setCharAt(valuesScriptBuilder.length() - 1, ')');
// sql 模板占位符替换
String columnScript = columnScriptBuilder.toString();
String valuesScript = valuesScriptBuilder.toString();
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), columnScript, valuesScript);
// === mybatis 主键逻辑处理：主键生成策略，以及主键回填=======
String keyColumn = null;
String keyProperty = null;
// 表包含主键处理逻辑,如果不包含主键当普通字段处理
if (StringUtils.isNotBlank(tableInfo.getKeyProperty())) {
if (tableInfo.getIdType() == IdType.AUTO) {
/** 自增主键 */
keyGenerator = new Jdbc3KeyGenerator();
keyProperty = tableInfo.getKeyProperty();
keyColumn = tableInfo.getKeyColumn();
} else {
if (null != tableInfo.getKeySequence()) {
keyGenerator = TableInfoHelper.genKeyGenerator(sqlMethod.getMethod(), tableInfo, builderAssistant);
keyProperty = tableInfo.getKeyProperty();
keyColumn = tableInfo.getKeyColumn();
}
}
}
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addInsertMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource, keyGenerator, keyProperty, keyColumn);
}
}
更新sql构造，这里要注意字段上的字段策略（FieldStrategy），附上处理类
public class UpdateBatchByIds extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BATCH;
/**
* update table set key1=#{item.pro} , key2=#{item.pro2} where keycolom = %s
* */
StringBuilder withChevScript = new StringBuilder();
StringBuilder lastFiledScriptBuilder=new StringBuilder();
StringBuilder keyScriptBuilder = new StringBuilder();
if (StringUtils.isNotBlank(tableInfo.getKeyColumn())) {
keyScriptBuilder.append(tableInfo.getKeyColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + tableInfo.getKeyProperty()));
}
List fieldList = tableInfo.getFieldList();
for (int i = 0; i < fieldList.size(); i++) {
TableFieldInfo fieldInfo = fieldList.get(i);
Boolean isLast=(i==(fieldList.size()-1));
//有插入默认填充器的不参与赋值
if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {
continue;
}
boolean change = false;
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());
change = true;
}
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());
change = true;
}
if (change) {
withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));
withChevScript.append(COMMA).append("");
if(isLast&&lastFiledScriptBuilder.length()==0){
//如果没有其他字段替补，弄个占位的，不然会出现语法错误的情况
withChevScript.append(tableInfo.getKeyColumn()).append(EQUALS).append(tableInfo.getKeyColumn());
}
}else{
lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
}
//处理多余的逗号
if(!StringUtils.isBlank(lastFiledScriptBuilder)&&!StringUtils.isBlank(withChevScript)){
int leftChevIndex= withChevScript.lastIndexOf(LEFT_CHEV);
if(withChevScript.charAt(leftChevIndex-1)!=','){
withChevScript.replace(leftChevIndex,leftChevIndex+1,",<");
}
if(lastFiledScriptBuilder.lastIndexOf(COMMA)==lastFiledScriptBuilder.length()-1){
lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length()-1);
}
}
withChevScript.append(lastFiledScriptBuilder);
// sql 模板占位符替换
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);
}
}
public class SQLConditionWrapper {
public final static String ITEM = "item";
public static StringBuilder appendNotNull(StringBuilder builder, String property) {
return appendEnd(appendStart(builder, getCondition(property)));
}
public static StringBuilder appendNotEmpty(StringBuilder builder, String property) {
StringBuilder condition = getCondition(property);
StringBuilder append = appendStart(builder, condition)
.append(" ").append(AND).append(" ").append(condition).append(EXCLAMATION_MARK).append(EQUALS).append(" ").append("''");
return appendEnd(append);
}
private static StringBuilder appendEnd(StringBuilder builder) {
builder.append("\"")
.append(RIGHT_CHEV);
return builder;
}
private static StringBuilder appendStart(StringBuilder builder, StringBuilder item) {
builder.append(LEFT_CHEV)
.append("if test=\"")
.append(item).append(EXCLAMATION_MARK).append(EQUALS).append(NULL);
return builder;
}
public static StringBuilder getCondition(String property) {
return new StringBuilder()
.append(ITEM).append(DOT).append(property);
}
}
然后就自定义mapper及sql注入器
public interface CustomMapperextends BaseMapper { /** * 批量插入 * @param collection 批量插入数据 * @return ignore */ int insertBatch(@Param("collection") Collection collection); /** * 批量更新 * @param collection * @return */ int updateBatchByIds(@Param("collection") Collection collection); }
这里sql注入器要判断下是继承了该类，才进行方法扩展
@ConditionalOnExpression("${mybatis-plus.custom-mapper.enabled:true}")
@Component
public class CustomSqlInject extends DefaultSqlInjector {
//初始化时候会加载
@Override
public List getMethodList(Class mapperClass) {
List methodList = super.getMethodList(mapperClass);
//属于自己定义的mapper才添加方法
if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(CustomMapper.class)) {
methodList.add(new InsertBatch());
methodList.add(new UpdateBatchByIds());
}
if (((ParameterizedTypeImpl) mapperClass.getGenericInterfaces()[0]).getRawType().equals(ComposeKeyMapper.class)) {
methodList.add(new SelectByComposeKeys());
methodList.add(new SelectIdsByComposeKeys());
methodList.add(new UpdateByComposeKeys());
methodList.add(new InsertBatch());
}
return methodList;
}
}
可以直接注入到spring里面，或者通过进行设置
GlobalConfigUtils.getGlobalConfig(sqlSessionFactory.getConfiguration()).setSqlInjector(xx)
测试一下，定义实体，下面的typeHandler可以去掉，
@TableName(
value = "demo"
)
@Data
@Accessors(chain = true)
public class Demo extends BaseEntity {
private static final long serialVersionUID = 1L;
@TableId("id")
private Long id;
@TableField("name")
private String name;
@TableField(
value = "age",
typeHandler = LongFormatAESEncryptHandler.class
)
private Long age;
@TableField(
value = "secret",
typeHandler = StringFormatAESEncryptHandler.class
)
private String secret;
@TableField(
value = "CREATED_ID",
fill = FieldFill.INSERT
)
private Long createdId;
@TableField(
value = "CREATED_BY",
fill = FieldFill.INSERT
)
private String createdBy;
@TableField(
value = "CREATION_DATE",
fill = FieldFill.INSERT
)
private Date creationDate;
@TableField(
value = "CREATED_BY_IP",
fill = FieldFill.INSERT
)
private String createdByIp;
@TableField(
value = "LAST_UPDATED_ID",
fill = FieldFill.UPDATE
)
private Long lastUpdatedId;
@TableField(
value = "LAST_UPDATED_BY",
fill = FieldFill.UPDATE
)
private String lastUpdatedBy;
@TableField(
value = "LAST_UPDATE_DATE",
fill = FieldFill.INSERT_UPDATE
)
private Date lastUpdateDate;
@TableField(
value = "LAST_UPDATED_BY_IP",
fill = FieldFill.UPDATE
)
private String lastUpdatedByIp;
}
继承自定义mapper
public interface TempMapper extends CustomMapper{ }
controller了的两个方法，可以支持事务
@GetMapping("/testBatch")
@Transactional(rollbackFor = Exception.class)
public void testBatch() {
List demos = new LinkedList<>();
for (int i = 0; i < 10; i++) {
Demo de = new Demo().setAge(Long.valueOf(i))
.setId(Long.valueOf(i + 1))
.setName("test" + i)
.setSecret(UUID.randomUUID().toString());
demos.add(de);
}
tempMapper.insertBatch(demos);
}
@GetMapping("/testBatch2")
@Transactional(rollbackFor = Exception.class)
public void testBatch2() {
List demos = new LinkedList<>();
for (int i = 0; i < 5; i++) {
Demo de = new Demo().setAge(Long.valueOf(i))
.setId(Long.valueOf(i + 1))
.setName("test-change" + i)
.setSecret(UUID.randomUUID().toString());
demos.add(de);
}
tempMapper.updateBatchByIds(demos);
//int i=1/0;
}
对于自定sql注入，还可以抽取一些公用的方法进行添加，比如逻辑删除，版本号更新，进行联合主键的批量修改和查询，下面给出联合主键的处理方案
下面是构造根据wrapper和联合主键进行查询的，核心也是定义好sql，然后进行注入，但这里需要自定义一个注解来标识哪个是联合主键
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface ComposeKey {
}
public class SelectByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_BY_COMPOSEKEYS;
//select #{ew.sqlSelect} from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
}
}
String finalSql = String.format(sqlTemplate, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);
}
}
更新操作
public class UpdateByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.UPDATE_BY_COMPOSEKEYS;
/**
* update table set key1=#{item.pro} , key2=#{item.pro2} where keycolom = %s
*/
StringBuilder withChevScript = new StringBuilder();
StringBuilder lastFiledScriptBuilder = new StringBuilder();
StringBuilder keyScriptBuilder = new StringBuilder();
StringBuilder placeHolder = new StringBuilder();
List fieldList = tableInfo.getFieldList();
for (int i = 0; i < fieldList.size(); i++) {
TableFieldInfo fieldInfo = fieldList.get(i);
Boolean isLast = (i == (fieldList.size() - 1));
if (fieldInfo.getField().isAnnotationPresent(ComposeKey.class)) {
keyScriptBuilder.append(" ").append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + fieldInfo.getProperty()))
.append(" ").append(AND);
placeHolder.append(fieldInfo.getColumn()).append(EQUALS).append(fieldInfo.getColumn()).append(COMMA);
continue;
}
//有插入默认填充器或者主键的不参与赋值
if (fieldInfo.isWithInsertFill() && !fieldInfo.isWithUpdateFill()) {
continue;
}
boolean change = false;
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_NULL) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotNull(withChevScript, fieldInfo.getProperty());
change = true;
}
if (Objects.equals(fieldInfo.getUpdateStrategy(), FieldStrategy.NOT_EMPTY) && !fieldInfo.isWithUpdateFill()) {
SQLConditionWrapper.appendNotEmpty(withChevScript, fieldInfo.getProperty());
change = true;
}
if (change) {
withChevScript.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString()));
withChevScript.append(COMMA).append("");
if (isLast && lastFiledScriptBuilder.length() == 0) {
//如果没有其他字段替补，弄个占位的，不然会出现语法错误的情况
if (placeHolder.length() > 0) {
//删除多余的逗号
placeHolder.deleteCharAt(placeHolder.length() - 1);
withChevScript.append(placeHolder);
}
}
} else {
lastFiledScriptBuilder.append(fieldInfo.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.getCondition(fieldInfo.getProperty()).toString())).append(COMMA);
}
}
if (placeHolder.length() == 0) {
throw new ApiException("not composeKey found in class:" + modelClass.getName());
}
//处理多余的逗号
if (!StringUtils.isBlank(lastFiledScriptBuilder) && !StringUtils.isBlank(withChevScript)) {
int leftChevIndex = withChevScript.lastIndexOf(LEFT_CHEV);
if (withChevScript.charAt(leftChevIndex - 1) != ',') {
withChevScript.replace(leftChevIndex, leftChevIndex + 1, ",<");
}
if (lastFiledScriptBuilder.lastIndexOf(COMMA) == lastFiledScriptBuilder.length() - 1) {
lastFiledScriptBuilder.deleteCharAt(lastFiledScriptBuilder.length() - 1);
}
}
if(!StringUtils.isBlank(keyScriptBuilder)){
int i = keyScriptBuilder.lastIndexOf(AND);
keyScriptBuilder.delete(i,i+AND.length());
}
withChevScript.append(lastFiledScriptBuilder);
// sql 模板占位符替换
String sql = String.format(sqlMethod.getSql(), tableInfo.getTableName(), withChevScript, keyScriptBuilder);
// 模板写入
SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
return this.addUpdateMappedStatement(mapperClass, modelClass, sqlMethod.getMethod(), sqlSource);
}
}
public class SelectIdsByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.SELECT_IDS_BY_COMPOSEKEYS;
//select composekeys from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
StringBuilder select=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
select.append(composeKey.getColumn());
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
select.append(COMMA);
}
}
String finalSql = String.format(sqlTemplate,select, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addSelectMappedStatementForTable(mapperClass,sqlMethod.getMethod(),sqlSource,tableInfo);
}
}
public class DeleteByComposeKeys extends AbstractMethod {
@Override
public MappedStatement injectMappedStatement(Class mapperClass, Class modelClass, TableInfo tableInfo) {
CustomSqlMethodEnum sqlMethod = CustomSqlMethodEnum.DELETE_BY_COMPOSEKEYS;
//delete from table_name where (composekey1=xx and composekey2=xx) or (composekey1=xx1 and composekey2=xx1)
String sqlTemplate = sqlMethod.getSql();
String tableName = tableInfo.getTableName();
List composeKeys = tableInfo.getFieldList().stream().filter(e -> e.getField().isAnnotationPresent(ComposeKey.class))
.collect(Collectors.toList());
if(CollectionUtils.isEmpty(composeKeys)){
throw new ApiException("not composeKey found in class:"+modelClass.getName());
}
StringBuilder builder=new StringBuilder();
for (int i = 0; i < composeKeys.size(); i++) {
TableFieldInfo composeKey = composeKeys.get(i);
builder.append(composeKey.getColumn()).append(EQUALS).append(SqlScriptUtils.safeParam(SQLConditionWrapper.ITEM + DOT + composeKey.getProperty()));
if(i!=composeKeys.size()-1){
builder.append(" ").append(AND).append(" ");
}
}
String finalSql = String.format(sqlTemplate, tableName, builder);
SqlSource sqlSource = languageDriver.createSqlSource(configuration, finalSql, modelClass);
return this.addDeleteMappedStatement(mapperClass, sqlMethod.getMethod(), sqlSource);
}
}
定义mappe类，这里对于原生的方法就不进行支持了
public interface ComposeKeyMapperextends CustomMapper { /** * @param params 查询的主键入参 * @param wrapper 查询的列会用到 ew.sqlSelect * @return */ List selectByComposeKeys(@Param("collection") Collection params, @Param(Constants.WRAPPER) Wrapper wrapper); /** * 批量更新 * * @param params */ void updateByComposeKeys(@Param("collection") Collection params); /** * 只查询主键 * * @param params * @return */ List selectIdsByComposeKeys(@Param("collection") Collection params); /** * 联合主键删除 * @param params * @return */ int deleteByComposeKeys(@Param("collection")Collection params); /** * 下面的方法不支持 * @param entity * @return */ @Override default int updateById(T entity) { throw new UnsupportedOperationException(); } @Override default int updateBatchByIds(Collection collection) { throw new UnsupportedOperationException(); } @Override default T selectById(Serializable id) { throw new UnsupportedOperationException(); } @Override default List selectBatchIds(Collection idList) { throw new UnsupportedOperationException(); } @Override default int deleteBatchIds(Collection idList){ throw new UnsupportedOperationException(); } @Override default int deleteById(Serializable id){ throw new UnsupportedOperationException(); } }
可以看到查询是按照预期给出的，也支持wrapper形式的查询
要注意，xml文件里的优先级是比自定义注入的优先级高的，这里没给出单个update，单个查询，单个删除的方法，这些都可以根据自己业务需求弄一下，项目上没用到就不写了
对于sqlSession也可以自己做一些小优化
类型有reuse，编译一次可以继续服用，使用场景：执行同一个sql，参数值不同
默认的simple是每次都会编译一下
batch相当于一个会话里面执行多条sql
reuse示例
public static void executeReuse(Consumerconsumer) { SqlSessionFactory factory = SpringContextHolder.getBean(SqlSessionFactory.class); SqlSession sqlSession = factory.openSession(ExecutorType.REUSE, true); try { consumer.accept(sqlSession); } finally { sqlSession.close(); } }
到此这篇关于mybatis-plus拦截器、字段填充器、类型处理器、表名替换、SqlInjector(联合主键处理)的文章就介绍到这了,更多相关mybatis-plus拦截器、字段填充器、类型处理器、表名替换内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！