在spring boot中创建自定义查询时出错

Question

I am new to spring boot and I am facing the below error when adding queries to my code,

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'testController': Unsatisfied dependency expressed through field 'testService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'testService': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract rest.Test rest.services.TestService.findByXY(java.lang.String)!

below are my code files,

Test.java

@Entity
public class Test {
@Id
private int id;
@Column
private String x;
@Column
private String y;

public Test() {

}

public Test(int id, String x, String y) {
    this.id = id;
    this.x = x;
    this.y = y;
}
}

TestService.java

public interface TestService extends CrudRepository<Test, Integer> {
@Query("select id, x, y from test where x = :x")
Employee findByXY(@Param("x") String x);
}

TestController.java

@Controller
public class TestController {

@Autowired
private TestService testService;

@GetMapping("/get-x")
public Employee findX() {
    //System.out.println(testService.findByXY("123"));
    return testService.findByXY("123");
}
}

PS: I am following this tutorial page - link to tutorial

Thanks in advance !!

Answer 1

The error is clear :

Validation failed for query for method public abstract rest.Test rest.services.TestService.findByXY(java.lang.String)!

The syntax is not correct for a JPQL query :

 @Query("select id, x, y from test where x = :x")
 Employee findByXY(@Param("x") String x);

Select rather a Test and returns also a type that matches to your query :

 @Query("select t from Test t where t.x = :x")
 Test findByXY(@Param("x") String x);

Otherwise, specify a native query if you want to do that as hrdkisback suggested, by adding nativeQuery = true .

Answer 2

This query :

select id, x, y from test where x = :x

return 3 parameters id , x , and y and not an object of type Employee

So the return type should be List<Object[]> and not Employee

@Query("select id, x, y from test where x = :x")
List<Object[]> findByXY(@Param("x") String x);

---

Then you can iterate through this list like this :

List<Object[]> listTest = findByXY(x);
List<Test> resultList = new ArrayList<>();

for (Object[] test : listTest) {
    resultList.add(
            new Test((Integer) test[0],
                    (String) test[1],
                    (String) test[2])
    );
}

Answer 3

You have write native query so, Try to pass nativeQuery true like

@Query("select id, x, y from test where x = :x", nativeQuery = true)

Or you can write HQL query

@Query("SELECT t.id, tx, ty FROM Test t where tx = :x")

Please refer this link for more info. https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.at-query