Spring-mybatis结合的底层原理
1.项目前期准备
1.1 导入maven jar包
<dependencies>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-contextartifactId>
<version>5.2.5.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-txartifactId>
<version>5.2.5.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>5.2.5.RELEASEversion>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatisartifactId>
<version>3.5.1version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatis-springartifactId>
<version>1.3.1version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>5.1.9version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druidartifactId>
<version>1.1.12version>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.11version>
<scope>testscope>
dependency>
dependencies>
1.2项目相关的文件夹
说明：
- mapper文件夹：存所有的sql语句的接口
- service文件夹：存所有具体的实现的方法
- spring-mybatis文件夹：存所有整合spring和mybatis的文件
- resources文件夹存所有的资源文件
1.2.1 UserMapper.java文件
package com.nq.mapper;
import org.apache.ibatis.annotations.Select;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 0:24
*/
public interface UserMapper {
@Select("select 'user'")
String selectById();
}
1.2.2 AppConfig.java文件
package com.nq.service;
import org.springframework.context.annotation.ComponentScan;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:59
*/
@ComponentScan("com.nq")
public class AppConfig {
}
1.2.3 UserService.java文件
package com.nq.service;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:45
*/
@Component
public class UserService {
@Autowired
private UserMapper userMapper;
public void test(){
System.out.println(userMapper.selectById());
}
}
1.2.4 mybatis.xml文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理 -->
<transactionManager type="JDBC"/>
<!-- 数据库连接池 -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url"
value="jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8&useSSL=false"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
</configuration>
1.2.5 Test.java文件
package com.nq.service;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.io.IOException;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/27 23:48
*/
public class Test {
public static void main(String[] args) throws IOException {
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
context.register(AppConfig.class);
context.refresh();
UserService userService=(UserService)context.getBean("userService");
userService.test();
}
}
说明：由于UserMapper是接口类型，不能被spring加载，所以spring加载的时候这里就要解决接口不能够被加载的情况，其二；由于UserMapper是执行sql语句，所有需要Mybatis生成UserMapper代理对象注入到UserMapper类型当中。
2.手写spring-mybatis执行过程
2.1 NickelFactoryBean.java文件
package com.nq.mybatis.spring;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.stereotype.Component;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 16:00
*/
@Component
public class NickelFactoryBean implements FactoryBean {
@Override
public Object getObject() throws Exception {
Object proxyInstance = Proxy.newProxyInstance(NickelFactoryBean.class.getClassLoader(), new Class[]{UserMapper.class}, new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
return null;
}
});
return proxyInstance;
}
@Override
public Class<?> getObjectType() {
return UserMapper.class;
}
}
说明：这里让UserMapper接口成为一个bean对象，这样程序就不会报错了
说明：这里确实让UserMapper成为一个bean对象了，但是这里会有一个问题，假如我们建立一个OrderMappe文件的话，这里不能识别OrderMapper对象
2.2建立OrderMapper对象和UserService对象
1.OrderMapper.java对象
package com.nq.mapper;
import org.apache.ibatis.annotations.Select;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 0:24
*/
public interface OrderMapper {
@Select("select 'order'")
String selectById();
}
2.UserService.java对象修改
package com.nq.service;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:45
*/
@Component
public class UserService {
@Autowired
private UserMapper userMapper;
@Autowired
private OrderMapper orderMapper;
public void test(){
System.out.println(userMapper.selectById());
System.out.println(orderMapper.selectById());
}
}
3.测试结果
说明：无法读取到OrderMapper对象
2.3让每一个mapper文件都成为bean对象
1.修改NickelFactoryBean.java文件，这里可以建立一个外部对象的形式，对所有的接口进行赋值
package com.nq.mybatis.spring;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.stereotype.Component;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 16:00
*/
public class NickelFactoryBean implements FactoryBean {
private Class mapperInterface;
public NickelFactoryBean(Class mapperInterface) {
this.mapperInterface = mapperInterface;
}
@Override
public Object getObject() throws Exception {
Object proxyInstance = Proxy.newProxyInstance(NickelFactoryBean.class.getClassLoader(), new Class[]{mapperInterface}, new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println(method.getName());
return null;
}
});
return proxyInstance;
}
@Override
public Class<?> getObjectType() {
return mapperInterface;
}
}
注意：这里需要去掉@Component注解，不然有这个注解spring将会加载一次，这和多个mapper去使用相违背。
2.Test方法中指定对对象成为bean对象
package com.nq.service;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import com.nq.mybatis.spring.NickelFactoryBean;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.io.IOException;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/27 23:48
*/
public class Test {
public static void main(String[] args) throws IOException {
AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
context.register(AppConfig.class);
AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition.setBeanClass(NickelFactoryBean.class);
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
context.registerBeanDefinition("userMapper",beanDefinition);
AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition1.setBeanClass(NickelFactoryBean.class);
beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
context.registerBeanDefinition("orderMapper",beanDefinition1);
context.refresh();
UserService userService=(UserService)context.getBean("userService");
userService.test();
}
}
3.Test结果显示
说明；这里我们把每一个mapper接口创建为bean的形式，但是这里有一个问题，假如出现第三mapper文件，我们在这里需要又去添加一个，思考这里有什么方式去注册bean呢
2.4NickelBeanDefinitionRegistryPostProcess.java文件通过继承BeanDefinitionRegistryPostProcessor去注册对应的接口
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:17
*/
@Component
public class NickelBeanDefinitionRegistryPostProcess implements BeanDefinitionRegistryPostProcessor {
@Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition.setBeanClass(NickelFactoryBean.class);
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
registry.registerBeanDefinition("userMapper",beanDefinition);
AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition1.setBeanClass(NickelFactoryBean.class);
beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
registry.registerBeanDefinition("orderMapper",beanDefinition1);
}
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
}
}
说明；通过这种获取方式，依然没有解决新加mapper文件的时候，需要增加修改代码的形式，所以这里我们需要通过spring扫描的方式去修改mapper文件的动态获取
2.5我们通过提供注解的形式，得到需要扫描的路径，提供NickelMapperScan注解
package com.nq.mybatis.spring;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:24
*/
@Retention(RetentionPolicy.RUNTIME)//运行时
@Target(ElementType.TYPE)//注解只能写在类上面
public @interface NickelMapperScan {
String value();
}
2.6ImportBeanDefinitionRegistrar实现接口的方式我们也能够进行注册
2.6.1修改NickelBeanDefinitionRegistryPostProcess文件
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:17
*/
//@Component
public class NickelBeanDefinitionRegistryPostProcess implements BeanDefinitionRegistryPostProcessor {
@Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
// AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
// beanDefinition.setBeanClass(NickelFactoryBean.class);
// beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
// registry.registerBeanDefinition("userMapper",beanDefinition);
//
// AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
// beanDefinition1.setBeanClass(NickelFactoryBean.class);
// beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
// registry.registerBeanDefinition("orderMapper",beanDefinition1);
}
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
}
}
2.6.2创建NickelImportBeanDefinitionRegisty.java实现接口ImportBeanDefinitionRegistrar
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:32
*/
public class NickelImportBeanDefinitionRegisty implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition.setBeanClass(NickelFactoryBean.class);
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
registry.registerBeanDefinition("userMapper",beanDefinition);
AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition1.setBeanClass(NickelFactoryBean.class);
beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
registry.registerBeanDefinition("orderMapper",beanDefinition1);
}
}
2.6.3这里我们需要NickelImportBeanDefinitionRegisty生效，需要在AppConfig中导入
package com.nq.service;
import com.nq.mybatis.spring.NickelImportBeanDefinitionRegisty;
import com.nq.mybatis.spring.NickelMapperScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:59
*/
@ComponentScan("com.nq")
@NickelMapperScan("com.nq.mapper")
@Import(NickelImportBeanDefinitionRegisty.class)
public class AppConfig {
}
2.6.4测试运行效果
2.7获取扫描路径
2.7.1把注解移动到扫描类上
1.修改AppConfig文件
package com.nq.service;
import com.nq.mybatis.spring.NickelImportBeanDefinitionRegisty;
import com.nq.mybatis.spring.NickelMapperScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:59
*/
@ComponentScan("com.nq")
@NickelMapperScan("com.nq.mapper")
public class AppConfig {
}
2.修改NickelMapperScan文件
package com.nq.mybatis.spring;
import org.springframework.context.annotation.Import;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:24
*/
@Retention(RetentionPolicy.RUNTIME)//运行时
@Target(ElementType.TYPE)//注解只能写在类上面
@Import(NickelImportBeanDefinitionRegisty.class)
public @interface NickelMapperScan {
String value();
}
3在NickelImportBeanDefinitionRegisty获取扫描的路径
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.stereotype.Component;
import java.util.Map;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:32
*/
public class NickelImportBeanDefinitionRegisty implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
//获取扫描路径
Map<String, Object> annotationAttributes = importingClassMetadata.getAnnotationAttributes(NickelMapperScan.class.getName());
String path = (String)annotationAttributes.get("value");
System.out.println(path);
AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition.setBeanClass(NickelFactoryBean.class);
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
registry.registerBeanDefinition("userMapper",beanDefinition);
AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition1.setBeanClass(NickelFactoryBean.class);
beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
registry.registerBeanDefinition("orderMapper",beanDefinition1);
}
}
说明：打印结果如下
4.通过spring的扫描逻辑获取扫描路径
1.创建类NickelClassPathBeanDefinitionScan继承spring扫描类ClassPathBeanDefinitionScanner
package com.nq.mybatis.spring;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/29 14:31
*/
public class NickelClassPathBeanDefinitionScan extends ClassPathBeanDefinitionScanner {
public NickelClassPathBeanDefinitionScan(BeanDefinitionRegistry registry) {
super(registry);
}
}
2.NickelImportBeanDefinitionRegisty获取NickelClassPathBeanDefinitionScan得到扫描类
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.stereotype.Component;
import java.util.Map;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:32
*/
public class NickelImportBeanDefinitionRegisty implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
//获取扫描路径
Map<String, Object> annotationAttributes = importingClassMetadata.getAnnotationAttributes(NickelMapperScan.class.getName());
String path = (String)annotationAttributes.get("value");
System.out.println(path);
NickelClassPathBeanDefinitionScan nickelClassPathBeanDefinitionScan=new NickelClassPathBeanDefinitionScan(registry);
nickelClassPathBeanDefinitionScan.scan(path);
AbstractBeanDefinition beanDefinition= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition.setBeanClass(NickelFactoryBean.class);
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(UserMapper.class);//userMapper UserMapper代理对象
registry.registerBeanDefinition("userMapper",beanDefinition);
AbstractBeanDefinition beanDefinition1= BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
beanDefinition1.setBeanClass(NickelFactoryBean.class);
beanDefinition1.getConstructorArgumentValues().addGenericArgumentValue(OrderMapper.class);//orderMapper OrderMapper代理对象
registry.registerBeanDefinition("orderMapper",beanDefinition1);
}
}
说明：由于spring扫描方法只能获取扫描类，而不能获取扫描接口。
5.NickelClassPathBeanDefinitionScan通过重写isCandidateComponent方法修饰，实现只能扫描接口
package com.nq.mybatis.spring;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
import org.springframework.core.type.classreading.MetadataReader;
import java.io.IOException;
import java.util.Set;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/29 14:31
*/
public class NickelClassPathBeanDefinitionScan extends ClassPathBeanDefinitionScanner {
//注册对象
public NickelClassPathBeanDefinitionScan(BeanDefinitionRegistry registry) {
super(registry);
}
/**
* 获取扫描类是否有值
* @param basePackages
* @return
*/
@Override
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Set<BeanDefinitionHolder> beanDefinitionHolders = super.doScan(basePackages);
return beanDefinitionHolders;
}
/**
* 判断是否是接口
* @param beanDefinition
* @return
*/
@Override
protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
return beanDefinition.getMetadata().isInterface();
}
}
说明：由于spring扫描只会扫描includeFilters里面的类，这里的类指的是类上面加了@Component类才会被扫描到。
6.在NickelClassPathBeanDefinitionScan时候，重写isCandidateComponent(MetadataReader metadataReader)方法，让方法都返回true
1.重写isCandidateComponent方法
package com.nq.mybatis.spring;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
import org.springframework.core.type.classreading.MetadataReader;
import java.io.IOException;
import java.util.Set;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/29 14:31
*/
public class NickelClassPathBeanDefinitionScan extends ClassPathBeanDefinitionScanner {
//注册对象
public NickelClassPathBeanDefinitionScan(BeanDefinitionRegistry registry) {
super(registry);
}
/**
* 获取扫描类是否有值
* @param basePackages
* @return
*/
@Override
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Set<BeanDefinitionHolder> beanDefinitionHolders = super.doScan(basePackages);
return beanDefinitionHolders;
}
/**
* 判断是否是接口
* @param beanDefinition
* @return
*/
@Override
protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
return beanDefinition.getMetadata().isInterface();
}
/**
* 重新是否包含的接口
* @param metadataReader
* @return
* @throws IOException
*/
@Override
protected boolean isCandidateComponent(MetadataReader metadataReader) throws IOException {
return true;
}
}
2.修改NickelImportBeanDefinitionRegisty方法
package com.nq.mybatis.spring;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.TypeFilter;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.util.Map;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 17:32
*/
public class NickelImportBeanDefinitionRegisty implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
//获取扫描路径
Map<String, Object> annotationAttributes = importingClassMetadata.getAnnotationAttributes(NickelMapperScan.class.getName());
String path = (String)annotationAttributes.get("value");
System.out.println(path);
NickelClassPathBeanDefinitionScan scanner=new NickelClassPathBeanDefinitionScan(registry);
scanner.scan(path);
}
}
3.修改NickelClassPathBeanDefinitionScan让方法的类都属于NickelFactoryBean对象
package com.nq.mybatis.spring;
import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.ClassPathBeanDefinitionScanner;
import org.springframework.core.type.classreading.MetadataReader;
import java.io.IOException;
import java.util.Set;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/29 14:31
*/
public class NickelClassPathBeanDefinitionScan extends ClassPathBeanDefinitionScanner {
//注册对象
public NickelClassPathBeanDefinitionScan(BeanDefinitionRegistry registry) {
super(registry);
}
/**
* 获取扫描类是否有值
* @param basePackages
* @return
*/
@Override
protected Set<BeanDefinitionHolder> doScan(String... basePackages) {
Set<BeanDefinitionHolder> beanDefinitionHolders = super.doScan(basePackages);
for (BeanDefinitionHolder beanDefinitionHolder : beanDefinitionHolders) {
BeanDefinition beanDefinition = beanDefinitionHolder.getBeanDefinition();
beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(beanDefinition.getBeanClassName());
beanDefinition.setBeanClassName(NickelFactoryBean.class.getName());
}
return beanDefinitionHolders;
}
/**
* 判断是否是接口
* @param beanDefinition
* @return
*/
@Override
protected boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
return beanDefinition.getMetadata().isInterface();
}
/**
* 重新是否包含的接口
* @param metadataReader
* @return
* @throws IOException
*/
@Override
protected boolean isCandidateComponent(MetadataReader metadataReader) throws IOException {
return true;
}
}
4.增加MemberMapper.java接口
package com.nq.mapper;
import org.apache.ibatis.annotations.Select;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 0:24
*/
public interface MemberMapper {
@Select("select 'user'")
String selectById();
}
5.修改UserService.java
package com.nq.service;
import com.nq.mapper.MemberMapper;
import com.nq.mapper.OrderMapper;
import com.nq.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:45
*/
@Component
public class UserService {
@Autowired
private UserMapper userMapper;
@Autowired
private OrderMapper orderMapper;
@Autowired
private MemberMapper memberMapper;
public void test(){
System.out.println(userMapper.selectById());
System.out.println(orderMapper.selectById());
System.out.println(memberMapper.selectById());
}
}
6.打印结果显示
结果显示
7.修改NickelFactoryBean代理，使得代理对象为mybatis
1.修改NickelFactoryBean对象
package com.nq.mybatis.spring;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 16:00
*/
public class NickelFactoryBean implements FactoryBean {
private Class mapperInterface;
private SqlSession sqlSession;
public NickelFactoryBean(Class mapperInterface) {
this.mapperInterface = mapperInterface;
}
@Autowired
public void setSqlSession(SqlSessionFactory sqlSessionFactory) {
sqlSessionFactory.getConfiguration().addMapper(mapperInterface);
this.sqlSession = sqlSessionFactory.openSession();
}
@Override
public Object getObject() throws Exception {
return sqlSession.getMapper(mapperInterface);
}
@Override
public Class<?> getObjectType() {
return mapperInterface;
}
}
2.修改AppConfig配置启动类
package com.nq.service;
import com.nq.mybatis.spring.NickelImportBeanDefinitionRegisty;
import com.nq.mybatis.spring.NickelMapperScan;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
import java.io.IOException;
import java.io.InputStream;
/**
* @author Nickel
* @version 1.0
* @date 2023/7/28 14:59
*/
@ComponentScan("com.nq")
@NickelMapperScan("com.nq.mapper")
public class AppConfig {
@Bean
public SqlSessionFactory sqlSessionFactory() throws IOException {
InputStream inputStream = Resources.getResourceAsStream("mybatis.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
return sqlSessionFactory;
}
}
代码路径：
https://gitee.com/nickel369369/spring-mybatis/mirrors#/