MyBatisPlus基础使用代码

package com.example.mybatisplus; import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.example.mybatisplus.dao.UserMapper; import com.example.mybatisplus.entity.User; import com.example.mybatisplus.entity.UserQuery; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.util.List; import java.util.Map; @SpringBootTest class MybatisplusApplicationTests { @Autowired private UserMapper userMapper; @Test public void testGetAll() { List<User> userList = userMapper.selectList(null); System.out.println(userList); } @Test void testSave() { User user = new User(); user.setName("Tina"); user.setPassword("tina"); user.setAge(12); user.setTel("4006184000"); userMapper.insert(user); } @Test void testDelete() { userMapper.deleteById(1629121977568542721L); } @Test void testUpdate() { User user = new User(); user.setId(1L); user.setName("Tom"); user.setPassword("tom"); userMapper.updateById(user); } @Test void testGetById() { User user = userMapper.selectById(2L); System.out.println(user); } //分页查询 @Test void testSelectPage(){ //1 创建IPage分页对象,设置分页参数,1为当前页码，3为每页显示的记录数 IPage<User> page=new Page<>(2,2); //2 执行分页查询 userMapper.selectPage(page,null); //3 获取分页结果 System.out.println("当前页码值："+page.getCurrent()); System.out.println("每页显示数："+page.getSize()); System.out.println("一共多少页："+page.getPages()); System.out.println("一共多少条数据："+page.getTotal()); System.out.println("数据："+page.getRecords()); } @Test void testGetAllQwLt(){ QueryWrapper qw = new QueryWrapper(); qw.lt("age",18); List<User> userList = userMapper.selectList(qw); System.out.println(userList); } @Test void testGetAllLqwLt(){ QueryWrapper<User> qw = new QueryWrapper<User>(); qw.lambda().lt(User::getAge, 10);//添加条件 List<User> userList = userMapper.selectList(qw); System.out.println(userList); } @Test void testGetAllLqwLt1(){ LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.lt(User::getAge, 10); List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllLqwMulti(){ // LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); // lqw.lt(User::getAge, 30); // lqw.gt(User::getAge, 10); // List<User> userList = userMapper.selectList(lqw); // System.out.println(userList); LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.lt(User::getAge, 30).gt(User::getAge, 10); List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllLqwOr(){ LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.lt(User::getAge, 10).or().gt(User::getAge, 30); List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllQueryParam(){ // //模拟页面传递过来的查询数据 // UserQuery uq = new UserQuery(); // uq.setAge(10); // uq.setAge2(30); // LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); // if(null != uq.getAge2()){ // lqw.lt(User::getAge, uq.getAge2()); // } // if( null != uq.getAge()) { // lqw.gt(User::getAge, uq.getAge()); // } // List<User> userList = userMapper.selectList(lqw); // System.out.println(userList); //模拟页面传递过来的查询数据 UserQuery uq = new UserQuery(); uq.setAge(10); // uq.setAge2(30); LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.lt(null!=uq.getAge2(),User::getAge, uq.getAge2()); lqw.gt(null!=uq.getAge(),User::getAge, uq.getAge()); List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllSelect(){ // LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); // lqw.select(User::getId,User::getName,User::getAge); // List<User> userList = userMapper.selectList(lqw); // System.out.println(userList); QueryWrapper<User> qw = new QueryWrapper<User>(); qw.select("id","name","age","tel"); List<User> userList = userMapper.selectList(qw); System.out.println(userList); } @Test void testGetAllFunc(){ QueryWrapper<User> lqw = new QueryWrapper<User>(); //lqw.select("count(*) as count"); //SELECT count(*) as count FROM user //lqw.select("max(age) as maxAge"); //SELECT max(age) as maxAge FROM user //lqw.select("min(age) as minAge"); //SELECT min(age) as minAge FROM user //lqw.select("sum(age) as sumAge"); //SELECT sum(age) as sumAge FROM user lqw.select("avg(age) as avgAge"); //SELECT avg(age) as avgAge FROM user List<Map<String, Object>> userList = userMapper.selectMaps(lqw); System.out.println(userList); } @Test void testGetAllGroup(){ QueryWrapper<User> lqw = new QueryWrapper<User>(); lqw.select("count(*) as count,tel"); lqw.groupBy("tel"); List<Map<String, Object>> list = userMapper.selectMaps(lqw); System.out.println(list); } @Test void testGetAllEqual(){ LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.eq(User::getName, "Jerry").eq(User::getPassword, "jerry"); User loginUser = userMapper.selectOne(lqw); System.out.println(loginUser); } @Test void testGetAllBetween(){ LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.between(User::getAge, 10, 30); //SELECT id,name,password,age,tel FROM user WHERE (age BETWEEN ? AND ?) List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllLike(){ LambdaQueryWrapper<User> lqw = new LambdaQueryWrapper<User>(); lqw.likeRight(User::getName, "J"); //SELECT id,name,password,age,tel FROM user WHERE (name LIKE ?) List<User> userList = userMapper.selectList(lqw); System.out.println(userList); } @Test void testGetAllOrder(){ LambdaQueryWrapper<User> lwq = new LambdaQueryWrapper<>(); /** * condition ：条件，返回boolean， 当condition为true，进行排序，如果为false，则不排序 * isAsc:是否为升序，true为升序，false为降序 * columns：需要操作的列 */ lwq.orderBy(true,false, User::getId); List<User> userList = userMapper.selectList(lwq); System.out.println(userList); } }