Spring Data @Query查詢註解的使用（六）

 按照上一篇文章 咱們知道  咱們定義的方法  都要根據它的規範進行定義  否則就無法實用

 

這篇咱們講@Query 查詢註解   咱們就能夠不須要遵循它的方法規則去編寫  我們講@Query定義到方法上便可  下面我們經過例子來說

 

本案例對應的方法------------------> getEmployeeByAge  這裏咱們能夠定義本身的sql 

package org.springdata.repository;

import org.springdata.domain.Employee;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.Repository;
import org.springframework.data.repository.RepositoryDefinition;

import java.util.List;

/***
 *
 */
@RepositoryDefinition(domainClass = Employee.class, idClass = Integer.class)
public interface EmployeeRepository /*extends Repository<Employee,Integer>*/ {
    /**
     * 根據名字找員工
     * desc  你們能夠發現  我只聲明瞭一個方法  並無寫任何的實現類   哦了  就這樣  我們寫個實現類
     * @param name
     * @return
     */
    public Employee findByName(String name);


    // name 根據模糊查詢  而且 年齡<多少歲的員工
    public List<Employee> findByNameIsStartingWithAndAgeLessThan(String name, Integer gae);


    // names in ('','','') 年齡小於多少
    public List<Employee> findByNameInOrAgeLessThan(List<String> names,Integer age);


    //獲取年齡最大的信息 注意 from Employee 的是類名  不是表名
    @Query(" select o  from  Employee o where o.age=(select max(age) from Employee t1)")
    public Employee getEmployeeByAge();
}

測試類 

　　對應的方法 ---------->testgetEmployeeByAge

package org.springdata;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springdata.domain.Employee;
import org.springdata.repository.EmployeeRepository;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.ArrayList;
import java.util.List;

/**
 * 測試類
 */
public class SpringDataTest {

    private ApplicationContext ctx = null;

    private EmployeeRepository employeeRepository = null;

    @Before
    public void setup(){
        ctx = new ClassPathXmlApplicationContext("beans_news.xml");
        employeeRepository = ctx.getBean(EmployeeRepository.class);
        System.out.println("setup");
    }

    @After
    public void tearDown(){
        ctx = null;
        System.out.println("tearDown");
    }

    @Test
    public void testEntityManagerFactory(){

    }

    @Test
    public void testFindByName(){
        System.out.println(employeeRepository);
        Employee employee = employeeRepository.findByName("zhangsan");
        System.out.println("id:" + employee.getId()
                + " , name:" + employee.getName()
                + " ,age:" + employee.getAge());
    }

    @Test
    public void testfindByNameIsStartingWithAndAgeLessThan(){
        System.out.println(employeeRepository);
        List<Employee> employees = employeeRepository.findByNameIsStartingWithAndAgeLessThan("wang",50);
        for (Employee employee: employees) {
            System.out.println("id:" + employee.getId()
                    + " , name:" + employee.getName()
                    + " ,age:" + employee.getAge());
        }
    }

    @Test
    public void testfindByNameInOrAgeLessThan(){
        List<String> names = new ArrayList<String>();
        names.add("wangwu1");
        names.add("wangwu2");
        names.add("wangwu3");
        System.out.println(employeeRepository);
        List<Employee> employees = employeeRepository.findByNameInOrAgeLessThan(names,50);
        for (Employee employee: employees) {
            System.out.println("id:" + employee.getId()
                    + " , name:" + employee.getName()
                    + " ,age:" + employee.getAge());
        }
    }


    @Test
    public void testgetEmployeeByAge(){
        Employee employee = employeeRepository.getEmployeeByAge();
            System.out.println("id:" + employee.getId()
                    + " , name:" + employee.getName()
                    + " ,age:" + employee.getAge());
    }
}

輸出結果

　　

我們看下數據庫表最大的年齡是否是這條記錄

　　

 再來一個  仍是在 EmployeeRepository 加方法

　　

 //獲取name包含 哪些 而且年齡等於多少歲
    @Query("select o from Employee o where o.name like %?1% and o.age = ?2")
    public List<Employee> querayParams(String name,Integer age);

而後編寫測試類

　　

@Test
    public void tesquerayParams(){
        List<Employee> employees = employeeRepository.querayParams("wangwu",12);
        for (Employee employee: employees) {
            System.out.println("id:" + employee.getId()
                    + " , name:" + employee.getName()
                    + " ,age:" + employee.getAge());
        }
    }

看下輸出結果

　　

 

very good  就那麼簡單