SpringDataJPA笔记(6)-value注解的使用

网页浏览地址

https://blog.csdn.net/yingziisme/article/details/89819290

使用查询的时候可以使用value注解，也是一种视图查询

1. 在类上面使用Lombok的value注解

@Value
public class NameEntity {
    String name;
    Long id;
}

添加对应查询方法

<T> List<T> findByAgeGreaterThan(int age, Class<T> type);

测试方法

@ApiOperation(value = "find", httpMethod = "GET")
@GetMapping("/find")
public List<NamesOnly> find(@RequestParam int age) {
    return catRepository.findByAge(age);
}

2. 在接口类上面使用org.springframework.beans.factory.annotation.Value的value注解

public interface NamesOnly {
    String getName();

    @Value("#{target.name + ' ' + target.id}")
    String getFullName();

    @Value("#{@valueUtils.getName(target)}")
    String getValue();
}

添加对应查询方法

List<NamesOnly> findByAge(int age);

3. 使用泛型将返回类传入查询方法

<T> List<T> findByAgeGreaterThan(int age, Class<T> type);

<T> List<T> findBy(Class<T> type);

<T> Page<T> findBy(Pageable pageable, Class<T> type);

添加对应的查询方法

  @ApiOperation(value = "findType", httpMethod = "GET")
    @GetMapping("/find/type")
    public List<NamesOnly> findType() {
        return catRepository.findBy(NamesOnly.class);
    }

    @ApiOperation(value = "findType2", httpMethod = "GET")
    @GetMapping("/find/type2")
    public List<NameEntity> findType2() {
        return catRepository.findBy(NameEntity.class);
    }

    @ApiOperation(value = "findTypeAge", httpMethod = "GET")
    @GetMapping("/find/type/age")
    public List<NamesOnly> findTypeAge(@RequestParam int age) {
        return catRepository.findByAgeGreaterThan(age, NamesOnly.class);
    }

    @ApiOperation(value = "findTypeAge2", httpMethod = "GET")
    @GetMapping("/find/type/age2")
    public List<NameEntity> findTypeAge2(@RequestParam int age) {
        return catRepository.findByAgeGreaterThan(age, NameEntity.class);
    }

    @ApiOperation(value = "findTypePage", httpMethod = "GET")
    @GetMapping("/find/type/page")
    public Page<NamesOnly> findTypePage(@RequestParam int pageSize, @RequestParam int pageNum) {
        Pageable pageable = PageRequest.of(pageNum, pageSize);
        return catRepository.findBy(pageable, NamesOnly.class);
    }

    @ApiOperation(value = "findTypePage2", httpMethod = "GET")
    @GetMapping("/find/type/page2")
    public Page<NameEntity> findTypePage2(@RequestParam int pageSize, @RequestParam int pageNum) {
        Pageable pageable = PageRequest.of(pageNum, pageSize);
        return catRepository.findBy(pageable, NameEntity.class);
    }

源码参考 https://github.com/yingziisme/spring-boot-jpa-demo