javaee 第7章 mybatis框架(4学时).ppt

JavaEE架构,第7章 Mybatis框架,7.1 Mybatis简介 7.2 Mybatis快速入门 7.3 基本CRUD操作,7.1 Mybatis简介,MyBatis是一个支持普通SQL查询、存储过程和高级映射的优秀持久层框架 MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装 MyBatis可以使用简单的XML或注解用于配置和原始映射，将接口和Java的POJO（Plain Ordinary Java Objects，普通的Java对象）映射成数据库中的记录返回】,7.2 Mybatis快速入门,数据库：,create database testdb; use testdb; create table users( id int auto_increment not null, username varchar(20) not null, password varchar(20), primary key(id) );,Mybatis入门示例：,步骤1： 添加mysql-connector-java依赖； 在pom.xml中新添Mybatis依赖：, mysql mysql-connector-java 5.1.45 , org.mybatis mybatis 3.4.5 ,步骤2：添加Mybatis配置文件,在src/main/resources/mybatis下新建Mybatis-config.xml文件：,,,配置Mysql数据库连接,,userMapper.xml详见后页,添加映射资源文件,,步骤3：创建实体类User,在src/main/java/entity包下创建User类：,package entity; public class User { int id; String username; String password; //getter和setter省略 @Override public String toString() { return “User [id=“ + id + “, username=“ + username + “, password=“ + password + “]“; } },User.ava,步骤4：创建sql映射文件userMapper.xml,在src/main/resources/mapper下新建userMapper.xml ：, select * from users where id= #{id} ,userMapper.xml,步骤5：主程序,在src/main/java下新建Test.java：,import java.io.IOException; import java.io.InputStream; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import entity.User; public class Test { public static void main(String[] args) throws IOException { String resource = “mybatis/mybatis-config.xml“; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = “mapper.userMapper.getUser“; //找到映射sql串 User user = sqlSession.selectOne(statement, 1); sqlSession.close(); System.out.println(user); } },Test.java,,读取Mybatis配置文件并创建session,执行查询返回一个唯一对象,【返回】,7.3 基本CRUD操作,1. 基于XML的实现 2. 基于注解的实现,1. 基于XML的实现, select * from users where id= #{id} insert into users(username,password) values(#{username},#{password}) select * from users delete from users where id=#{id} update users set username=#{username},password=#{password} where id=#{id} ,userMapper.xml,CRUD代码（Create）,public void testAdd(){ String resource = “mybatis-config.xml“; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = “mapper.userMapper.addUser“; User user = new User(); user.setUsername(“yy“); user.setPassword(“yy“); int retResult = sqlSession.insert(statement,user); sqlSmit(); sqlSession.close(); },CRUD代码（Retrieve）,public void testGetAllUsers (){ String resource = “mybatis-config.xml“; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = “mapper.userMapper.getAllUsers“; List listUsers = sqlSession.selectList(statement); sqlSession.close(); System.out.println(listUsers); },CRUD代码（Update）,public void testUpdate(){ String resource = “mybatis-config.xml“; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = “mapper.userMapper.updateUser“; User user = new User(); user.setId(6); user.setUsername(“hello“); user.setPassword(“hello“); int retResult = sqlSession.update(statement,user); //修改id=6用户 sqlSmit(); sqlSession.close(); },CRUD代码（Delete）,public void testDelete(){ String resource = “mybatis-config.xml“; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = “mapper.userMapper.deleteUser“; int retResult = sqlSession.delete(statement,7); //删除id=7用户 sqlSmit(); sqlSession.close(); },【返回】,2. 基于注解的实现,首先创建sql接口，接口中定义CRUD抽象方法； 在方法名上添加@Insert、@Delete、@Update、@Select注解来指明方法要执行的SQL；（把XML配置的sql写到方法上） 然后将sql接口添加到Mybatis配置文件中； 最后使用时，先获得映射接口，然后直接使用接口CRUD方法。

1) 定义sql映射接口,package mapper; public interface IUserMapper { @Insert(“insert into users(username,password) values(#{username},#{password})“) public int addUser(User user); @Delete(“delete from users where id=#{id}“) public int deleteUser(int id); @Update(“update users set username=#{username},password=#{password} where id=#{id}“) public int updateUser(User user); @Select(“select * from users where id=#{id}“) public User getUserById(int id); @Select(“select * from users“) public List getAllUsers(); },IUserMapper.java,(2) 将sql映射接口添加到Mybatis配置文件,… …,mybatis-config.java,,(3) CRUD代码（Create）,public void testAdd(){ String 。