1. 实战更新

package com.gblfy.springboot.mybatisplus.mapper;import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.conditions.query.LambdaQueryChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.update.LambdaUpdateChainWrapper;
import com.gblfy.springboot.mybatisplus.entity.User;
import lombok.extern.slf4j.Slf4j;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
@Slf4j
public class UserUpdateTest {@Autowiredprivate UserMapper userMapper;@Testpublic void updateById() {User user = new User();user.setId(1238735228017610754l);user.setEmail("gblfy@163.com");user.setAge(22);int rows = userMapper.updateById(user);System.out.println("影响记录数:" + rows);}//PDATE user SET age=?, email=? WHERE id=?/*** 根据 whereEntity 条件，更新记录** @param entity        实体对象 (set 条件值,可以为 null)* @param updateWrapper 实体对象封装操作类（可以为 null,里面的 entity 用于生成 where 语句）*/@Testpublic void updateByWrapper() {UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();updateWrapper.eq("name", "Tom").eq("age", 28);User user = new User();user.setEmail("gblfy2@sino.com");user.setAge(22);int rows = userMapper.update(user, updateWrapper);System.out.println("影响记录数:" + rows);}//UPDATE user SET age=?, email=? WHERE name = ? AND age = ?/*** 更新方式1* 当表中字段很多,只更新少量字段的值（建议使用）*/@Testpublic void updateByWrapper2() {UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();updateWrapper.eq("name", "Tom").eq("age", 28).set("age", 30);int rows = userMapper.update(null, updateWrapper);System.out.println("影响记录数:" + rows);//UPDATE user SET age=?, email=? WHERE name = ? AND age = ?}/*** WrapperLambda 更新方式2*/@Testpublic void updateByWrapperLambda() {LambdaUpdateWrapper<User> lambdaUpdateWrapper = Wrappers.<User>lambdaUpdate();lambdaUpdateWrapper.eq(User::getName, "Tom").eq(User::getAge, 28).set(User::getAge, 30);int rows = userMapper.update(null, lambdaUpdateWrapper);System.out.println("影响记录数:" + rows);}/*** WrapperLambdaChain 更新方式3*/@Testpublic void updateByWrapperLambdaChain() {boolean sign = new LambdaUpdateChainWrapper<User>(userMapper).eq(User::getName, "Tom").eq(User::getAge, 22).set(User::getAge, 30).update();System.out.println(sign);}//UPDATE user SET age=? WHERE name = ? AND age = ?
}