Mybatis-Plus条件构造器

Poetry-Distance

已于 2023-09-28 21:17:22 修改

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分类专栏： mybatis-plus 文章标签： java tomcat mybatis-plus

于 2023-09-10 17:20:33 首次发布

本文链接：https://blog.youkuaiyun.com/qi341500/article/details/132781582

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Mybatis-Plus条件构造器

1、allEq：全部

allEq(Map<R, V> params)
allEq(Map<R, V> params, boolean null2IsNull)
allEq(boolean condition, Map<R, V> params, boolean null2IsNull)

全部eq(或个别isNull)

个别参数说明:

params : key为数据库字段名,value为字段值
null2IsNull : 为true则在map的value为null时调用 isNull 方法,为false时则忽略value为null的

示例：

@Test
    public void AllEq() {
        //设置条件
        Map<String,Object> params = new HashMap<>();
        params.put("name", "坤坤");
        params.put("age", "18");
        params.put("password", null);
        QueryWrapper<Users> wrapper = new QueryWrapper<>();
        //SQL:SELECT id,user_name,password,name,age,email FROM tb_user WHERE password IS NULL AND name = ? AND age = ?
        //wrapper.allEq(params);

        //去掉为空的条件
        //SQL:SELECT id,user_name,password,name,age,email FROM tb_user WHERE name = ? AND age = ?
        //wrapper.allEq(params,false);

        //过滤条件
        //SQL:SELECT id,user_name,password,name,age,email FROM tb_user WHERE name = ?
        wrapper.allEq((k, v) -> (k.equals("name") || k.equals("id")),params);
        //SQL:SELECT id,user_name,password,name,age,email FROM tb_user WHERE name = ? AND age = ?
        wrapper.allEq((k, v) -> (k.equals("name") || k.equals("age")),params);
        
        List<Users> users = this.userMapper.selectList(wrapper);
        for (Users user : users) {
            System.out.println(user);
        }

    }

2、eq：等于

eq(R column, Object val)
eq(boolean condition, R column, Object val)

等于 =
例: eq("name", "老王")--->name = '老王'

示例：

//查询一条数据
    @Test
    public void selectOne() {

        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("user_name","11");
        //查询一条，如果多余1条会报异常
        Users user = this.userMapper.selectOne(queryWrapper);
        System.out.println("result = " + user);
    }

3、ne：不等于

ne(R column, Object val)
ne(boolean condition, R column, Object val)

不等于 <>
例: ne("name", "老王")--->name <> '老王'

示例：

//不等于
    @Test
    public void selectListNe() {
        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        //SQL: SELECT id,user_name,password,name,age,email FROM tb_user WHERE name <> ? 
        queryWrapper.ne("name","王五");
        //根据条件查询集合
        List<Users> userList = this.userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }

4、gt：大于

gt(R column, Object val)
gt(boolean condition, R column, Object val)

大于 >
例: gt("age", 18)--->age > 18

//大于
    @Test
    public void selectListGt() {
        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        //SQL: SELECT id,user_name,password,name,age,email FROM tb_user WHERE age > ? 
        queryWrapper.gt("age","20");
        //根据条件查询集合
        List<Users> userList = this.userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }

5、ge：大于等于

ge(R column, Object val)
ge(boolean condition, R column, Object val)

大于等于 >=
例: ge("age", 18)--->age >= 18

//大于等于
    @Test
    public void selectListGe() {
        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        //SQL: SELECT id,user_name,password,name,age,email FROM tb_user WHERE age >= ? 
        queryWrapper.ge("age","20");//
        //根据条件查询集合
        List<Users> userList = this.userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }

6、lt：小于

lt(R column, Object val)
lt(boolean condition, R column, Object val)

小于 <
例: lt("age", 18)--->age < 18

 //小于
    @Test
    public void selectListLt() {
        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        //SQL: SELECT id,user_name,password,name,age,email FROM tb_user WHERE age < ?
        queryWrapper.lt("age","20");//
        //根据条件查询集合
        List<Users> userList = this.userMapper.selectList(queryWrapper);
        userList.forEach(System.out::println);
    }

7、le：小于等于

le(R column, Object val)
le(boolean condition, R column, Object val)

小于等于 <=
例: le("age", 18)--->age <= 18

//小于等于
    @Test
    public void selectListLe() {
        QueryWrapper<Users> queryWrapper = new QueryWrapper<>();
        //SQL: SELECT id,user_name,password,name,age,email FROM tb_user WHERE age <= ?
        queryWrapper.le("age","20");//
        //根据条件查询集

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