SSM框架之Mybatis（3）dao层开发
Mybatis（3）dao层开发
以实现类完成CRUD操作
1、持久层dao层接口的书写
src\main\java\dao\IUserDao.java
package dao;
import domain.QueryVo;
import domain.User;
import java.util.List;
public interface IUserDao {
/**
* 查询所有数据
* @return
*/
List<User> findAll();
//List<User> findAll();
/**
* 添加用户
* @param user
*/
void addUser(User user);
/**
* 更新用户
* @param user
*/
void updateUser(User user);
/**
* 删除用户
* @param id
*/
void deleteUser(int id);
/**
* 根据id查询用户
* @param id
*/
User findById(int id);
/**
* 模糊查询用户信息
* @return
*/
List<User> findByName(String str);
/**
* 使用聚合函数查询
*/
int findTotal();
}
2、持久层实现类的书写
src\main\java\dao\impl\UserDaoImpl.java
package dao.impl;
import dao.IUserDao;
import domain.QueryVo;
import domain.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import java.util.List;
public class UserDaoImpl implements IUserDao {
private SqlSessionFactory factory;
public UserDaoImpl() {
}
public UserDaoImpl(SqlSessionFactory factory) {
this.factory = factory;
}
public List<User> findAll() {
SqlSession session = factory.openSession();
List<User> list = session.selectList("dao.IUserDao.findAll");
session.close();
return list;
}
public void addUser(User user) {
SqlSession session = factory.openSession();
int i = session.insert("dao.IUserDao.addUser", user);
session.commit();
System.out.println("这是i的值========="+i);
session.close();
}
public void updateUser(User user) {
SqlSession session = factory.openSession();
int update = session.update("dao.IUserDao.updateUser", user);
session.commit();
session.close();
}
public void deleteUser(int id) {
SqlSession session = factory.openSession();
int delete = session.delete("dao.IUserDao.deleteUser", id);
session.commit();
session.close();
}
public User findById(int id) {
SqlSession session = factory.openSession();
User list = session.selectOne("dao.IUserDao.findById",id);
session.close();
return list;
}
public List<User> findByName(String str) {
SqlSession session = factory.openSession();
List<User> list = session.selectList("dao.IUserDao.findByName", str);
session.close();
return list;
}
public List<User> findByVo(QueryVo vo) {
return null;
}
public int findTotal() {
SqlSession session = factory.openSession();
int o = session.selectOne("dao.IUserDao.findTotal");
return o;
}
}
3、持久层配置文件的书写
src\main\resources\dao\IUserDao.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="dao.IUserDao">
<select id="findAll" resultType="domain.User">
select * from user
</select>
<!--<select id="findAll" resultType="domain.User">
select * from user
</select>-->
<insert id="addUser" parameterType="domain.User">
<!--获取插入用户的id-->
<!--会把id存入传入的user对象中-->
<selectKey keyProperty="id" resultType="int" order="AFTER">
select last_insert_id();
</selectKey>
insert into user (username,address,sex,birthday) value (#{username},#{address},#{sex},#{birthday})
</insert>
<delete id="deleteUser" parameterType="java.lang.Integer">
delete from user where id=#{id}
</delete>
<update id="updateUser" parameterType="domain.User">
update user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday}
</update>
<select id="findById" parameterType="int" resultType="domain.User">
select * from user where id=#{id}
</select>
<select id="findByName" resultType="domain.User" parameterType="String">
<!--select * from user where username like '%${value}%'-->
<!-- 使用上面方式模糊查询时Statment对象通过字符串拼接的方式连接sql语句
下面的sql语句使用PrepatedStatement的参数占位符有预处理，
所以下面这种方式使用的多
-->
select * from user where username like #{str}
</select>
<select id="findTotal" resultType="int">
select count(id) from user
</select>
</mapper>
4、测试类的书写
src\test\java\test\MybatisTest.java
package test;
import dao.IUserDao;
import dao.impl.UserDaoImpl;
import domain.QueryVo;
import domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.scripting.xmltags.TextSqlNode;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
public class MybatisTest {
/**
* 测试mybatis的CRUD操作
*/
InputStream in;
IUserDao uesrdao;
@Before
public void init() throws Exception {
in = Resources.getResourceAsStream("SqlMapConfig.xml");
SqlSessionFactory build = new SqlSessionFactoryBuilder().build(in);
uesrdao = new UserDaoImpl(build);
}
@After
public void destory() throws Exception {
in.close();
}
@Test
public void testFainAll(){
//查询所有
List<User> users = uesrdao.findAll();
for (User usr: users
) {
System.out.println(usr);
}
}
@Test
public void testAddUser(){
//添加用户
User user = new User();
user.setUsername("wf");
user.setAddress("中国");
user.setSex("男");
user.setBirthday(new Date());
System.out.println(user);
uesrdao.addUser(user);
System.out.println(user);
}
@Test
public void testUpdateUser(){
//更新用户
User user = new User();
user.setUsername("gx");
user.setAddress("中国");
user.setSex("女");
user.setBirthday(new Date());
uesrdao.updateUser(user);
}
@Test
public void testDeleteUser(){
//删除用户
uesrdao.deleteUser(51);
}
@Test
public void testFindOne(){
//通过id查找用户
User user = uesrdao.findById(48);
System.out.println(user);
}
@Test
public void testFindByName(){
//通过模糊查询查找用户
List<User> users = uesrdao.findByName("%g%");
//List<User> users = uesrdao.findByName("g");
for(User user:users){
System.out.println(user);
}
}
@Test
public void testFindTotal(){
//通过聚合函数查询
int a = uesrdao.findTotal();
System.out.println(a);
}
}
