SpringDataJPA笔记(6)-value注解的使用

喜欢ヅ旅行 2022-02-05 04:55 322阅读 0赞

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 [GITHUB][]  
欢迎关注微信交流  
![在这里插入图片描述][70]

[GITHUB]: https://github.com/yingziisme/spring-boot-jpa-demo
[70]: /images/20220205/610f7b09482b47d6a5b0574450d0ada7.png