MyBatis-Plus 之Service CRUD 接口
Service CRUD 接口
- 1.0 Service CRUD 接口
-
- 1.1 IService接口
- 1.1 ServiceImpl实现类：
- 2.0 实现IService接口
-
- 2.1 创建Service 层Impl 层
- 2.2 写测试类
- 2.3 查询全部条数；
- 2.4 根据id删除；
- 2.5 批量添加；
文章顺序及整体目录可查看（点我即可）
1.0 Service CRUD 接口
1.1 IService接口
/*
* Copyright (c) 2011-2020, baomidou ([email protected]).
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.baomidou.mybatisplus.extension.service;
import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.toolkit.Assert;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.conditions.query.LambdaQueryChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.query.QueryChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.update.LambdaUpdateChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.update.UpdateChainWrapper;
import com.baomidou.mybatisplus.extension.toolkit.ChainWrappers;
import com.baomidou.mybatisplus.extension.toolkit.SqlHelper;
import org.springframework.transaction.annotation.Transactional;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import java.util.stream.Collectors;
/**
* 顶级 Service
*
* @author hubin
* @since 2018-06-23
*/
public interface IService<T> {
/**
* 默认批次提交数量
*/
int DEFAULT_BATCH_SIZE = 1000;
/**
* 插入一条记录（选择字段，策略插入）
*
* @param entity 实体对象
*/
default boolean save(T entity) {
return SqlHelper.retBool(getBaseMapper().insert(entity));
}
/**
* 插入（批量）
*
* @param entityList 实体对象集合
*/
@Transactional(rollbackFor = Exception.class)
default boolean saveBatch(Collection<T> entityList) {
return saveBatch(entityList, DEFAULT_BATCH_SIZE);
}
/**
* 插入（批量）
*
* @param entityList 实体对象集合
* @param batchSize 插入批次数量
*/
boolean saveBatch(Collection<T> entityList, int batchSize);
/**
* 批量修改插入
*
* @param entityList 实体对象集合
*/
@Transactional(rollbackFor = Exception.class)
default boolean saveOrUpdateBatch(Collection<T> entityList) {
return saveOrUpdateBatch(entityList, DEFAULT_BATCH_SIZE);
}
/**
* 批量修改插入
*
* @param entityList 实体对象集合
* @param batchSize 每次的数量
*/
boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize);
/**
* 根据 ID 删除
*
* @param id 主键ID
*/
default boolean removeById(Serializable id) {
return SqlHelper.retBool(getBaseMapper().deleteById(id));
}
/**
* 根据 columnMap 条件，删除记录
*
* @param columnMap 表字段 map 对象
*/
default boolean removeByMap(Map<String, Object> columnMap) {
Assert.notEmpty(columnMap, "error: columnMap must not be empty");
return SqlHelper.retBool(getBaseMapper().deleteByMap(columnMap));
}
/**
* 根据 entity 条件，删除记录
*
* @param queryWrapper 实体包装类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default boolean remove(Wrapper<T> queryWrapper) {
return SqlHelper.retBool(getBaseMapper().delete(queryWrapper));
}
/**
* 删除（根据ID 批量删除）
*
* @param idList 主键ID列表
*/
default boolean removeByIds(Collection<? extends Serializable> idList) {
if (CollectionUtils.isEmpty(idList)) {
return false;
}
return SqlHelper.retBool(getBaseMapper().deleteBatchIds(idList));
}
/**
* 根据 ID 选择修改
*
* @param entity 实体对象
*/
default boolean updateById(T entity) {
return SqlHelper.retBool(getBaseMapper().updateById(entity));
}
/**
* 根据 UpdateWrapper 条件，更新记录 需要设置sqlset
*
* @param updateWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper}
*/
default boolean update(Wrapper<T> updateWrapper) {
return update(null, updateWrapper);
}
/**
* 根据 whereEntity 条件，更新记录
*
* @param entity 实体对象
* @param updateWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper}
*/
default boolean update(T entity, Wrapper<T> updateWrapper) {
return SqlHelper.retBool(getBaseMapper().update(entity, updateWrapper));
}
/**
* 根据ID 批量更新
*
* @param entityList 实体对象集合
*/
@Transactional(rollbackFor = Exception.class)
default boolean updateBatchById(Collection<T> entityList) {
return updateBatchById(entityList, DEFAULT_BATCH_SIZE);
}
/**
* 根据ID 批量更新
*
* @param entityList 实体对象集合
* @param batchSize 更新批次数量
*/
boolean updateBatchById(Collection<T> entityList, int batchSize);
/**
* TableId 注解存在更新记录，否插入一条记录
*
* @param entity 实体对象
*/
boolean saveOrUpdate(T entity);
/**
* 根据 ID 查询
*
* @param id 主键ID
*/
default T getById(Serializable id) {
return getBaseMapper().selectById(id);
}
/**
* 查询（根据ID 批量查询）
*
* @param idList 主键ID列表
*/
default List<T> listByIds(Collection<? extends Serializable> idList) {
return getBaseMapper().selectBatchIds(idList);
}
/**
* 查询（根据 columnMap 条件）
*
* @param columnMap 表字段 map 对象
*/
default List<T> listByMap(Map<String, Object> columnMap) {
return getBaseMapper().selectByMap(columnMap);
}
/**
* 根据 Wrapper，查询一条记录
* 结果集，如果是多个会抛出异常，随机取一条加上限制条件 wrapper.last("LIMIT 1")
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default T getOne(Wrapper<T> queryWrapper) {
return getOne(queryWrapper, true);
}
/**
* 根据 Wrapper，查询一条记录
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
* @param throwEx 有多个 result 是否抛出异常
*/
T getOne(Wrapper<T> queryWrapper, boolean throwEx);
/**
* 根据 Wrapper，查询一条记录
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
Map<String, Object> getMap(Wrapper<T> queryWrapper);
/**
* 根据 Wrapper，查询一条记录
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
* @param mapper 转换函数
*/
<V> V getObj(Wrapper<T> queryWrapper, Function<? super Object, V> mapper);
/**
* 查询总记录数
*
* @see Wrappers#emptyWrapper()
*/
default int count() {
return count(Wrappers.emptyWrapper());
}
/**
* 根据 Wrapper 条件，查询总记录数
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default int count(Wrapper<T> queryWrapper) {
return SqlHelper.retCount(getBaseMapper().selectCount(queryWrapper));
}
/**
* 查询列表
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default List<T> list(Wrapper<T> queryWrapper) {
return getBaseMapper().selectList(queryWrapper);
}
/**
* 查询所有
*
* @see Wrappers#emptyWrapper()
*/
default List<T> list() {
return list(Wrappers.emptyWrapper());
}
/**
* 翻页查询
*
* @param page 翻页对象
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default <E extends IPage<T>> E page(E page, Wrapper<T> queryWrapper) {
return getBaseMapper().selectPage(page, queryWrapper);
}
/**
* 无条件翻页查询
*
* @param page 翻页对象
* @see Wrappers#emptyWrapper()
*/
default <E extends IPage<T>> E page(E page) {
return page(page, Wrappers.emptyWrapper());
}
/**
* 查询列表
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default List<Map<String, Object>> listMaps(Wrapper<T> queryWrapper) {
return getBaseMapper().selectMaps(queryWrapper);
}
/**
* 查询所有列表
*
* @see Wrappers#emptyWrapper()
*/
default List<Map<String, Object>> listMaps() {
return listMaps(Wrappers.emptyWrapper());
}
/**
* 查询全部记录
*/
default List<Object> listObjs() {
return listObjs(Function.identity());
}
/**
* 查询全部记录
*
* @param mapper 转换函数
*/
default <V> List<V> listObjs(Function<? super Object, V> mapper) {
return listObjs(Wrappers.emptyWrapper(), mapper);
}
/**
* 根据 Wrapper 条件，查询全部记录
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default List<Object> listObjs(Wrapper<T> queryWrapper) {
return listObjs(queryWrapper, Function.identity());
}
/**
* 根据 Wrapper 条件，查询全部记录
*
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
* @param mapper 转换函数
*/
default <V> List<V> listObjs(Wrapper<T> queryWrapper, Function<? super Object, V> mapper) {
return getBaseMapper().selectObjs(queryWrapper).stream().filter(Objects::nonNull).map(mapper).collect(Collectors.toList());
}
/**
* 翻页查询
*
* @param page 翻页对象
* @param queryWrapper 实体对象封装操作类 {@link com.baomidou.mybatisplus.core.conditions.query.QueryWrapper}
*/
default <E extends IPage<Map<String, Object>>> E pageMaps(E page, Wrapper<T> queryWrapper) {
return getBaseMapper().selectMapsPage(page, queryWrapper);
}
/**
* 无条件翻页查询
*
* @param page 翻页对象
* @see Wrappers#emptyWrapper()
*/
default <E extends IPage<Map<String, Object>>> E pageMaps(E page) {
return pageMaps(page, Wrappers.emptyWrapper());
}
/**
* 获取对应 entity 的 BaseMapper
*
* @return BaseMapper
*/
BaseMapper<T> getBaseMapper();
/**
* 以下的方法使用介绍:
*
* 一. 名称介绍
* 1. 方法名带有 query 的为对数据的查询操作, 方法名带有 update 的为对数据的修改操作
* 2. 方法名带有 lambda 的为内部方法入参 column 支持函数式的
*
* 二. 支持介绍
* 1. 方法名带有 query 的支持以 {@link ChainQuery} 内部的方法名结尾进行数据查询操作
* 2. 方法名带有 update 的支持以 {@link ChainUpdate} 内部的方法名为结尾进行数据修改操作
*
* 三. 使用示例,只用不带 lambda 的方法各展示一个例子,其他类推
* 1. 根据条件获取一条数据: `query().eq("column", value).one()`
* 2. 根据条件删除一条数据: `update().eq("column", value).remove()`
*
*/
/**
* 链式查询 普通
*
* @return QueryWrapper 的包装类
*/
default QueryChainWrapper<T> query() {
return ChainWrappers.queryChain(getBaseMapper());
}
/**
* 链式查询 lambda 式
* 注意：不支持 Kotlin
*
* @return LambdaQueryWrapper 的包装类
*/
default LambdaQueryChainWrapper<T> lambdaQuery() {
return ChainWrappers.lambdaQueryChain(getBaseMapper());
}
/**
* 链式更改 普通
*
* @return UpdateWrapper 的包装类
*/
default UpdateChainWrapper<T> update() {
return ChainWrappers.updateChain(getBaseMapper());
}
/**
* 链式更改 lambda 式
* 注意：不支持 Kotlin
*
* @return LambdaUpdateWrapper 的包装类
*/
default LambdaUpdateChainWrapper<T> lambdaUpdate() {
return ChainWrappers.lambdaUpdateChain(getBaseMapper());
}
/**
*
* 根据updateWrapper尝试更新，否继续执行saveOrUpdate(T)方法
* 此次修改主要是减少了此项业务代码的代码量（存在性验证之后的saveOrUpdate操作）
*
*
* @param entity 实体对象
*/
default boolean saveOrUpdate(T entity, Wrapper<T> updateWrapper) {
return update(entity, updateWrapper) || saveOrUpdate(entity);
}
}
1.1 ServiceImpl实现类：
/*
* Copyright (c) 2011-2020, baomidou ([email protected]).
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.baomidou.mybatisplus.extension.service.impl;
import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.enums.SqlMethod;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import com.baomidou.mybatisplus.core.toolkit.*;
import com.baomidou.mybatisplus.extension.service.IService;
import com.baomidou.mybatisplus.extension.toolkit.SqlHelper;
import org.apache.ibatis.binding.MapperMethod;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import org.apache.ibatis.reflection.ExceptionUtil;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.MyBatisExceptionTranslator;
import org.mybatis.spring.SqlSessionHolder;
import org.mybatis.spring.SqlSessionUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import java.io.Serializable;
import java.util.Collection;
import java.util.Map;
import java.util.Objects;
import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Function;
/**
* IService 实现类（ 泛型：M 是 mapper 对象，T 是实体 ）
*
* @author hubin
* @since 2018-06-23
*/
@SuppressWarnings("unchecked")
public class ServiceImpl<M extends BaseMapper<T>, T> implements IService<T> {
protected Log log = LogFactory.getLog(getClass());
@Autowired
protected M baseMapper;
@Override
public M getBaseMapper() {
return baseMapper;
}
protected Class<?> entityClass = currentModelClass();
/**
* 判断数据库操作是否成功
*
* @param result 数据库操作返回影响条数
* @return boolean
* @deprecated 3.3.1
*/
@Deprecated
protected boolean retBool(Integer result) {
return SqlHelper.retBool(result);
}
protected Class<T> currentModelClass() {
return (Class<T>) ReflectionKit.getSuperClassGenericType(getClass(), 1);
}
/**
* 批量操作 SqlSession
*
* @deprecated 3.3.0
*/
@Deprecated
protected SqlSession sqlSessionBatch() {
return SqlHelper.sqlSessionBatch(entityClass);
}
/**
* 释放sqlSession
*
* @param sqlSession session
* @deprecated 3.3.0
*/
@Deprecated
protected void closeSqlSession(SqlSession sqlSession) {
SqlSessionUtils.closeSqlSession(sqlSession, GlobalConfigUtils.currentSessionFactory(entityClass));
}
/**
* 获取 SqlStatement
*
* @param sqlMethod ignore
* @return ignore
*/
protected String sqlStatement(SqlMethod sqlMethod) {
return SqlHelper.table(entityClass).getSqlStatement(sqlMethod.getMethod());
}
/**
* 批量插入
*
* @param entityList ignore
* @param batchSize ignore
* @return ignore
*/
@Transactional(rollbackFor = Exception.class)
@Override
public boolean saveBatch(Collection<T> entityList, int batchSize) {
String sqlStatement = sqlStatement(SqlMethod.INSERT_ONE);
return executeBatch(entityList, batchSize, (sqlSession, entity) -> sqlSession.insert(sqlStatement, entity));
}
/**
* TableId 注解存在更新记录，否插入一条记录
*
* @param entity 实体对象
* @return boolean
*/
@Transactional(rollbackFor = Exception.class)
@Override
public boolean saveOrUpdate(T entity) {
if (null != entity) {
Class<?> cls = entity.getClass();
TableInfo tableInfo = TableInfoHelper.getTableInfo(cls);
Assert.notNull(tableInfo, "error: can not execute. because can not find cache of TableInfo for entity!");
String keyProperty = tableInfo.getKeyProperty();
Assert.notEmpty(keyProperty, "error: can not execute. because can not find column for id from entity!");
Object idVal = ReflectionKit.getMethodValue(cls, entity, tableInfo.getKeyProperty());
return StringUtils.checkValNull(idVal) || Objects.isNull(getById((Serializable) idVal)) ? save(entity) : updateById(entity);
}
return false;
}
@Transactional(rollbackFor = Exception.class)
@Override
public boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize) {
TableInfo tableInfo = TableInfoHelper.getTableInfo(entityClass);
Assert.notNull(tableInfo, "error: can not execute. because can not find cache of TableInfo for entity!");
String keyProperty = tableInfo.getKeyProperty();
Assert.notEmpty(keyProperty, "error: can not execute. because can not find column for id from entity!");
return executeBatch(entityList, batchSize, (sqlSession, entity) -> {
Object idVal = ReflectionKit.getMethodValue(entityClass, entity, keyProperty);
if (StringUtils.checkValNull(idVal) || Objects.isNull(getById((Serializable) idVal))) {
sqlSession.insert(tableInfo.getSqlStatement(SqlMethod.INSERT_ONE.getMethod()), entity);
} else {
MapperMethod.ParamMap<T> param = new MapperMethod.ParamMap<>();
param.put(Constants.ENTITY, entity);
sqlSession.update(tableInfo.getSqlStatement(SqlMethod.UPDATE_BY_ID.getMethod()), param);
}
});
}
@Transactional(rollbackFor = Exception.class)
@Override
public boolean updateBatchById(Collection<T> entityList, int batchSize) {
String sqlStatement = sqlStatement(SqlMethod.UPDATE_BY_ID);
return executeBatch(entityList, batchSize, (sqlSession, entity) -> {
MapperMethod.ParamMap<T> param = new MapperMethod.ParamMap<>();
param.put(Constants.ENTITY, entity);
sqlSession.update(sqlStatement, param);
});
}
@Override
public T getOne(Wrapper<T> queryWrapper, boolean throwEx) {
if (throwEx) {
return baseMapper.selectOne(queryWrapper);
}
return SqlHelper.getObject(log, baseMapper.selectList(queryWrapper));
}
@Override
public Map<String, Object> getMap(Wrapper<T> queryWrapper) {
return SqlHelper.getObject(log, baseMapper.selectMaps(queryWrapper));
}
@Override
public <V> V getObj(Wrapper<T> queryWrapper, Function<? super Object, V> mapper) {
return SqlHelper.getObject(log, listObjs(queryWrapper, mapper));
}
/**
* 执行批量操作
*
* @param consumer consumer
* @since 3.3.0
* @deprecated 3.3.1 后面我打算移除掉 {@link #executeBatch(Collection, int, BiConsumer)} }.
*/
@Deprecated
protected boolean executeBatch(Consumer<SqlSession> consumer) {
SqlSessionFactory sqlSessionFactory = SqlHelper.sqlSessionFactory(entityClass);
SqlSessionHolder sqlSessionHolder = (SqlSessionHolder) TransactionSynchronizationManager.getResource(sqlSessionFactory);
boolean transaction = TransactionSynchronizationManager.isSynchronizationActive();
if (sqlSessionHolder != null) {
SqlSession sqlSession = sqlSessionHolder.getSqlSession();
//原生无法支持执行器切换，当存在批量操作时，会嵌套两个session的，优先commit上一个session
//按道理来说，这里的值应该一直为false。
sqlSession.commit(!transaction);
}
SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH);
if (!transaction) {
log.warn("SqlSession [" + sqlSession + "] was not registered for synchronization because DataSource is not transactional");
}
try {
consumer.accept(sqlSession);
//非事物情况下，强制commit。
sqlSession.commit(!transaction);
return true;
} catch (Throwable t) {
sqlSession.rollback();
Throwable unwrapped = ExceptionUtil.unwrapThrowable(t);
if (unwrapped instanceof RuntimeException) {
MyBatisExceptionTranslator myBatisExceptionTranslator
= new MyBatisExceptionTranslator(sqlSessionFactory.getConfiguration().getEnvironment().getDataSource(), true);
throw Objects.requireNonNull(myBatisExceptionTranslator.translateExceptionIfPossible((RuntimeException) unwrapped));
}
throw ExceptionUtils.mpe(unwrapped);
} finally {
sqlSession.close();
}
}
/**
* 执行批量操作
*
* @param list 数据集合
* @param batchSize 批量大小
* @param consumer 执行方法
* @param 泛型
* @return 操作结果
* @since 3.3.1
*/
protected <E> boolean executeBatch(Collection<E> list, int batchSize, BiConsumer<SqlSession, E> consumer) {
Assert.isFalse(batchSize < 1, "batchSize must not be less than one");
return !CollectionUtils.isEmpty(list) && executeBatch(sqlSession -> {
int size = list.size();
int i = 1;
for (E element : list) {
consumer.accept(sqlSession, element);
if ((i % batchSize == 0) || i == size) {
sqlSession.flushStatements();
}
i++;
}
});
}
/**
* 执行批量操作（默认批次提交数量{@link IService#DEFAULT_BATCH_SIZE}）
*
* @param list 数据集合
* @param consumer 执行方法
* @param 泛型
* @return 操作结果
* @since 3.3.1
*/
protected <E> boolean executeBatch(Collection<E> list, BiConsumer<SqlSession, E> consumer) {
return executeBatch(list, DEFAULT_BATCH_SIZE, consumer);
}
}
2.0 实现IService接口
我们有了之前学习BaseMapd的经验之后我们来看些mapper的自带的service的方法有哪些妙用；
2.1 创建Service 层Impl 层
**UserService:**继承了mapper-plus的IService
package com.example.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.pojo.User;
public interface UserService extends IService<User> {
}
**UserServiceImpl:**继承了mapper-plus的ServiceImpl;我们传入的2个值一个是mapper（mapper接口）一个是user(实体类)
package com.example.service.Impl;
import com.baomidou.mybatisplus.extension.service.IService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.mapper.UserMapper;
import com.example.pojo.User;
import com.example.service.UserService;
import org.springframework.stereotype.Service;
@Service
public class UserSercieImpl extends ServiceImpl<UserMapper,User> implements UserService {
}
2.2 写测试类
新建 MyBatisPlusService 测试类；
package com.example;
import com.example.service.UserService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
public class MYBatisPlusService {
//引用servies的方法
@Autowired
private UserService userService;
}
2.3 查询全部条数；
/**
* 查询总条数
*/
@Test
public void SelectCount(){
int count = userService.count();
System.out.println("count"+count);
}
执行结果：
==> Preparing: SELECT COUNT( 1 ) FROM user
==> Parameters:
<== Columns: COUNT( 1 )
<== Row: 5
<== Total: 1
2.4 根据id删除；
/**
* 根据id删除
*/
@Test
public void removeById(){
boolean count = userService.removeById(3L);
System.out.println("count"+count);
if (count){
System.out.println("删除成功");
}else {
System.out.println("删除失败");
}
运行结果是：
==> Preparing: DELETE FROM user WHERE id=?
==> Parameters: 3(Long)
<== Updates: 1
2.5 批量添加；
/**
* 批量添加
*/
@Test
public void removeById1(){
List<User> list = new ArrayList<>();
for (int i = 0; i < 10; i++) {
User user = new User();
user.setName("闫文超"+i);
user.setAge(10+i);
user.setEmail("757631644"+i+i+1);
list.add(user);
}
boolean count = userService.saveBatch(list);
System.out.println("count"+count);
if (count){
System.out.println("批量添加成功");
}else {
System.out.println("批量添加失败");
}
}
运行结果为：
==> Preparing: INSERT INTO user ( id, name, age, email ) VALUES ( ?, ?, ?, ? )
==> Parameters: 1577321026130407426(Long), 闫文超0(String), 10(Integer), 757631644001(String)
==> Parameters: 1577321026298179585(Long), 闫文超1(String), 11(Integer), 757631644111(String)
==> Parameters: 1577321026298179586(Long), 闫文超2(String), 12(Integer), 757631644221(String)
==> Parameters: 1577321026298179587(Long), 闫文超3(String), 13(Integer), 757631644331(String)
==> Parameters: 1577321026298179588(Long), 闫文超4(String), 14(Integer), 757631644441(String)
==> Parameters: 1577321026298179589(Long), 闫文超5(String), 15(Integer), 757631644551(String)
==> Parameters: 1577321026298179590(Long), 闫文超6(String), 16(Integer), 757631644661(String)
==> Parameters: 1577321026298179591(Long), 闫文超7(String), 17(Integer), 757631644771(String)
==> Parameters: 1577321026298179592(Long), 闫文超8(String), 18(Integer), 757631644881(String)
==> Parameters: 1577321026298179593(Long), 闫文超9(String), 19(Integer), 757631644991(String)
counttrue
批量添加成功
此次service的演示到此为止；大家也可以根据接口实现去看看都有哪些实现；大家也可以去尝试下其他的玩法；由于内容太过简单；我这边就不多做介绍了；
大家有任何问题都可以留言；