Spring Data @Query查询注解的使用（六）

按照上一篇文章 我们知道  我们定义的方法  都要根据它的规范进行定义  不然就没法实用

这篇我们讲@Query 查询注解   我们就可以不需要遵循它的方法规则去编写  咱们讲@Query定义到方法上即可  下面咱们通过例子来讲

本案例对应的方法------------------> getEmployeeByAge  这里我们可以定义自己的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>*/ {
    /**
     * 根据名字找员工
     * desc  大家可以发现  我只声明了一个方法  并没有写任何的实现类   哦了  就这样  咱们写个实现类
     * @param name
     * @return
     */
    public Employee findByName(String name);

    // name 根据模糊查询  并且 年龄<多少岁的员工
    public List<Employee> findByNameIsStartingWithAndAgeLessThan(String name, Integer gae);

    // names in ('','','') 年龄小于多少
    public List<Employee> findByNameInOrAgeLessThan(List<String> names,Integer age);

    //获取年龄最大的信息 注意 from Employee 的是类名  不是表名
    @Query(" select o  from  Employee o where o.age=(select max(age) from Employee t1)")
    public Employee getEmployeeByAge();
}

测试类

　　对应的方法 ---------->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;

/**
 * 测试类
 */
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());
    }
}

输出结果

　　

咱们看下数据库表最大的年龄是不是这条记录

　　

再来一个  还是在 EmployeeRepository 加方法

　　

 //获取name包含 哪些 并且年龄等于多少岁
    @Query("select o from Employee o where o.name like %?1% and o.age = ?2")
    public List<Employee> querayParams(String name,Integer age);

然后编写测试类

　　

@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());
        }
    }

看下输出结果

　　

very good  就那么简单