mybatis-plus自定义排序的实现

2023-01-09 12:02

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需求：

先时间升序排序，相同的时间在按状态排序，
状态的顺序为1 在线 4 潜伏 2 隐身 3 离开，
状态相同在按姓名升序排序
对排序好的数据进行分页
运用mybatis-plus中QueryWrapper

1.导入依赖

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.1</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

2.配置文件

spring:
  # 配置数据源信息
  datasource:
    # 配置数据源类型
    type: com.zaxxer.hikari.HikariDataSource
    # 配置连接数据库信息
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mybatis_plus?characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456
 
mybatis-plus:
  configuration: # 配置MyBatis日志
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

3.创建分页需要的缓存

@Configuration
@MapperScan("scan.your.mapper.package")
public class  MybatisPlusConfig {
    
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.H2));
        return interceptor;
    }
 
}

4.创建实体类

@Data
public class User {
    private Integer id;
    private String name;
    private Integer age;
    private String email;
    private Integer state;//1 在线 4 潜伏 2 隐身 3 离开
    private Date time;
}

5.mapper

public interface UserMapper extends BaseMapper<User> {
}

在启动类上加了@MapperScan(“com.example.mapper”)

6.测试

  @Test
    void selectUser(){
        QueryWrapper<User> wrapper=new QueryWrapper<>();
        //时间升序排序
        wrapper.lambda().orderByAsc(User::getTime);
        //状态的自定义排序,和姓名排序
        wrapper.orderByAsc(" field(state,1,4,2,3)");
        wrapper.lambda().orderByAsc(User::getName);
        //分页
        Page page=new Page<>();
        page.setSize(3);//每页的长度
        page.setPages(1);//第几页
        userMapper.selectPage(page,wrapper);
    }