MyBatis-Plus条件构造器queryWrapper、updateWrapper用法

以QueryWrapper和UpdateWrapper为例

MyBatis-Plus条件构造器queryWrapper、updateWrapper用法_第1张图片

  1. /**
         * 

    * 根据根据 entity 条件,删除记录,QueryWrapper实体对象封装操作类(可以为 null) * 下方获取到queryWrapper后删除的查询条件为name字段为null的and年龄大于等于12的and email字段不为null的 * 同理写法条件添加的方式就不做过多介绍了。 *

    */ @Test public void delete() { QueryWrapper queryWrapper = new QueryWrapper<>(); queryWrapper .isNull("name") .ge("age", 12) .isNotNull("email"); int delete = mapper.delete(queryWrapper); System.out.println("delete return count = " + delete); }

    /**
         * 

    * 根据 entity 条件,查询一条记录, * 这里和上方删除构造条件一样,只是seletOne返回的是一条实体记录,当出现多条时会报错 *

    */ @Test public void selectOne() { QueryWrapper queryWrapper = new QueryWrapper<>(); queryWrapper.eq("name", "lqf"); User user = mapper.selectOne(queryWrapper); System.out.println(user); } /** *

    * 根据 Wrapper 条件,查询总记录数 *

    * * @param queryWrapper 实体对象 */ @Test public void selectCount() { QueryWrapper queryWrapper = new QueryWrapper<>(); queryWrapper.eq("name", "lqf"); Integer count = mapper.selectCount(queryWrapper); System.out.println(count); } /** *

    * 根据 entity 条件,查询全部记录 *

    * * @param queryWrapper 实体对象封装操作类(可以为 null)为null查询全部 */ @Test public void selectList() { List list = mapper.selectList(null); System.out.println(list); } /** *

    * 根据 Wrapper 条件,查询全部记录 *

    * * @param queryWrapper 实体对象封装操作类(可以为 null) */ @Test public void selectMaps() { QueryWrapper queryWrapper = new QueryWrapper<>(); queryWrapper.isNotNull("name"); List> maps = mapper.selectMaps(queryWrapper); for (Map map : maps) { System.out.println(map); } } /** * 打印结果 * {name=lqf, id=1046282328366391406, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391407, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391408, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391409, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391410, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391411, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391412, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391413, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391414, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391415, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391416, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391417, age=12, [email protected], status=false} * {name=lqf, id=1046282328366391418, age=12, [email protected], status=false} * json类型的键值对模式 */ /** *

    * 根据 entity 条件,查询全部记录(并翻页) *

    * * @param page 分页查询条件(可以为 RowBounds.DEFAULT) * @param queryWrapper 实体对象封装操作类(可以为 null) */ @Test public void selectPage() { Page page = new Page<>(1, 5); QueryWrapper queryWrapper = new QueryWrapper<>(); IPage userIPage = mapper.selectPage(page, queryWrapper); System.out.println(userIPage); } /** * 打印结果 * ==> Preparing: SELECT COUNT(1) FROM user * ==> Parameters: * <== Columns: COUNT(1) * <== Row: 100 * ==> Preparing: SELECT id,name,age,email,status FROM user LIMIT 0,5 * ==> Parameters: * <== Columns: id, name, age, email, status * <== Row: 1046282328366391319, lqf, 12, [email protected], 0 * <== Row: 1046282328366391320, lqf, 12, [email protected], 0 * <== Row: 1046282328366391321, lqf, 12, [email protected], 0 * <== Row: 1046282328366391322, lqf, 12, [email protected], 0 * <== Row: 1046282328366391323, lqf, 12, [email protected], 0 * <== Total: 5 * * * 这里需要在项目中加入分页插件 * @Bean * public PaginationInterceptor paginationInterceptor() { * return new PaginationInterceptor(); * } */ /** *

    * 根据 Wrapper 条件,查询全部记录(并翻页) *

    * * @param page 分页查询条件 * @param queryWrapper 实体对象封装操作类 */ @Test public void selectMapsPage() { Page page = new Page<>(1, 5); QueryWrapper queryWrapper = new QueryWrapper<>(); IPage> mapIPage = mapper.selectMapsPage(page, queryWrapper); System.out.println(mapIPage); } /** * 和上个分页同理只是返回类型不同 */ /** *

    * 根据 whereEntity 条件,更新记录 *

    * * @param entity 实体对象 (set 条件值,不能为 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) */ @Test public void update() { //修改值 User user = new User(); user.setStatus(true); user.setName("zhangsan"); //修改条件s UpdateWrapper userUpdateWrapper = new UpdateWrapper<>(); userUpdateWrapper.eq("name", "lqf"); int update = mapper.update(user, userUpdateWrapper); System.out.println(update); }

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