Spring Boot Jpa 多表关联查询问题

Question

jpa单表分页查询很简单一个自带的findall方法就搞定。那么类似下面的多表关联分页查询该如何解决呢？
SELECT
t.id,t.co_name,e.experiment_code,e.experiment_name
FROM
tb_component t,
tb_component_flow tf,
tb_experiment_apply e
WHERE
t.id = tf.component_id
AND tf.experiment_apply_id = e.id
AND e.experiment_name LIKE '%实验%'
_***跪求大佬们在线指点。**

Answer 1

1、将3个表对应的建了3个Entity。
2、返回结果t.id,t.co_name,e.experiment_code,e.experiment_name，对应的建立了一个实体类，如下：

 public class Component {
    private String id;
    private String co_name;
    private String experiment_code;
    private String experiment_name;

    public Component(String id, String co_name, String experiment_code, String experiment_name) {
        this.id = id;
        this.co_name = co_name;
        this.experiment_code = experiment_code;
        this.experiment_name = experiment_name;
    }
    //省略了get、set方法
}

实现代码：

 public void findAllComponent(String experiment_name) {
                //分页参数
        PageRequest pageRequest = new PageRequest(0, 2);
        Page<Component> page = componentRepo.findAll("%实验%", pageRequest);
        List<Component> components = page.getContent();
        for (Component component : components) {
            System.out.println(component.toString());
        }
    }

Repo：

 @Query(value = "SELECT new com.read.first.pojo.Component (t.id,t.co_name,e.experiment_code,e.experiment_name) \n" +
            "FROM\n" +
            "ComponentEntity t, ComponentFlowEntity tf, ExperimentApplyEntity e " +
            "WHERE\n" +
            "t.id = tf.component_id\n" +
            "AND tf.experiment_apply_id = e.id\n" +
            "AND e.experiment_name LIKE ?1 ")
    Page<Component> findAll(String experiment_name, Pageable pageable);

测试结果：
Component{id='1232131233', co_name='原件3', experiment_code='123', experiment_name='实验3'}
Component{id='1232131232', co_name='原件2', experiment_code='123', experiment_name='实验2'}

看到你的问题，自己测试了可以解决，手工打字不易，有疑问请留言。