MybatisPlus之QueryWrapper与LambdaQueryWrapper的用法及区别(亲测)
MybatisPlus之QueryWrapper与LambdaQueryWrapper
/**
* 1. QueryWrapper 用法示例
*/
List<UserDo> userList = userMapper.selectList(new QueryWrapper<UserDo>()
.like("email", "24252")
.between("age", 20, 22)
.or()
.eq("name", "zcx")
);
System.out.println("userList:" + userList.toString());
//2、排序用法
List<UserDo> users = userMapper.selectList(new QueryWrapper<UserDo>()
.eq("nick_name", "xx")
.orderByAsc("age") //升序
// .orderByDesc("age") //降序
.last("limit 0,3") //last用法:在sql末尾添加sql语句,有sql注入风险
);
System.out.println("users:"+users.toString());
/**
* 2. LambdaQueryWrapper 用法示例
*/
LambdaQueryWrapper<UserDo> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(UserDo::getAccount, account);
queryWrapper.eq(UserDo::getIsDelete, 0);
queryWrapper.like(UserDo::getName,"lk");
queryWrapper.between(UserDo::getAge,18,20);
// queryWrapper.orderByAsc(UserDo::getDeptNo);
UserDo user = userMapper.selectOne(queryWrapper);
Integer count = userMapper.selectCount(queryWrapper);
UserDo user1 = userMapper.selectOne(new LambdaQueryWrapper<UserDo>()
.eq(UserDo::getAccount, username));
/**
* 3. 区别
*
* QueryWrapper 的列名匹配使用的是 “数据库中的字段名(一般是下划线规则)”
* LambdaQueryWrapper 的列名匹配使用的是“Lambda的语法,偏向于对象”
* 不同写“列名”,而是使用纯java的方式,避免了拼写错误(LambdaQueryWrapper 的写法如果有错,
* 则在编译期就会报错,而QueryWrapper需要运行的时候调用该方法才会报错)
* 所以LambdaQueryWrapper 更优于 QueryWrapper
*/
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原文链接:https://blog.csdn.net/weixin_45723142/article/details/124410453
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