前期准备

开发环境的搭建工作完全可以参考jpa小例子。我们直接对前期使用的Person表进行操作，直接操作SQL我们直接在单元测试中展示。

代码

package com.nova.bean;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

import org.junit.Test;

public class NativeQueryTest {

    @Test
    public void checkTable() {
        // 可以验证生成表是否正确
        EntityManagerFactory factory = Persistence
                .createEntityManagerFactory("myJpa");
        factory.close();
    }

    /**
     * 插入数据
     * 
     * 这里在实现时忘记了开启事物，在对数据库进行insert、update、delete时必须开启事物进行操作
     */
    @Test
    public void create() {
        EntityManagerFactory emf = Persistence
                .createEntityManagerFactory("myJpa");
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        String sql = "insert into Person(context,name) values(?,?)";
        em.createNativeQuery(sql).setParameter(1, "this is a test!")
                .setParameter(2, "test").executeUpdate();
        em.getTransaction().commit();
        em.close();
        emf.close();
    }

    /**
     * 查询一条记录
     */
    @Test
    public void readOne() {
        EntityManagerFactory emf = Persistence
                .createEntityManagerFactory("myJpa");
        EntityManager em = emf.createEntityManager();
        String sql = "select * from Person";
        Query query = em.createNativeQuery(sql, Person.class);
        Person person = (Person) query.getSingleResult();
        System.out.println(person.getName() + "--" + person.getContext());
        em.close();
        emf.close();
    }

    /**
     * 查询一个列表
     */
    @Test
    public void readList() {
        EntityManagerFactory emf = Persistence
                .createEntityManagerFactory("myJpa");
        EntityManager em = emf.createEntityManager();
        String sql = "select * from Person";
        Query query = em.createNativeQuery(sql, Person.class);
        @SuppressWarnings("unchecked")
        List<Person> list = query.getResultList();
        for (Person person : list) {
            System.out.println(person.getName() + "--" + person.getContext());
        }
        em.close();
        emf.close();
    }

    /**
     * 查询表的某一列
     */
    @Test
    public void readOneColumn() {
        EntityManagerFactory emf = Persistence
                .createEntityManagerFactory("myJpa");
        EntityManager em = emf.createEntityManager();
        String sql = "select p.name from Person p";
        Query query = em.createNativeQuery(sql);
        @SuppressWarnings("unchecked")
        List<String> list = query.getResultList();
        for (String str : list) {
            System.out.println(str);
        }
        em.close();
        emf.close();
    }

}