JavaEE 第7章 Mybatis框架(4学时)幻灯片

1、JavaEE架构,1,2,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,2,6/22/2020,7.1 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】,3,6/22/2020,7.2 Mybatis快

2、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) );,4,6/22/2020,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 myba

3、tis 3.4.5 ,5,6/22/2020,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,6,6/22/2020,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 publ

4、ic String toString() return User id= + id + , username= + username + , password= + password + ; ,User.ava,7,6/22/2020,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,8,6/22/2020,步骤5：主程序,在src/main/java下新建Test.java：,import ja

5、va.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 m

6、ain(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(); Strin

7、g 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】,9,6/22/2020,7.3 基本CRUD操作,1. 基于XML的实现 2. 基于注解的实现,10,6/22/2020,1. 基于XML的实现, select * from users where id

8、= #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,11,6/22/2020,CRUD代码（Create）,public void testAdd() String resource = mybatis-config.xml; InputS

9、tream 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); u

10、ser.setPassword(yy); int retResult = sqlSession.insert(statement,user); sqlSmit(); sqlSession.close(); ,12,6/22/2020,CRUD代码（Retrieve）,public void testGetAllUsers () String resource = mybatis-config.xml; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFa

11、ctory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = mapper.userMapper.getAllUsers; List listUsers = sqlSession.selectList(statement); sqlSession.close(); System.out.println(listUsers); ,13,6/22/2020,CRUD代码（Update）,pub

12、lic 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.u

13、serMapper.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(); ,14,6/22/2020,CRUD代码（Delete）,public void testDelete() String resource = mybatis-config.xml; Input

14、Stream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); String statement = mapper.userMapper.deleteUser; int retResult = sqlSession.delete(statement

15、,7); /删除id=7用户 sqlSmit(); sqlSession.close(); ,【返回】,15,6/22/2020,2. 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。,16,6/22/2020,(1) 定义sql映射接口,package mapper; public interface IUserMapper Inser

16、t(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 u

17、sers where id=#id) public User getUserById(int id); Select(select * from users) public List getAllUsers(); ,IUserMapper.java,17,6/22/2020,(2) 将sql映射接口添加到Mybatis配置文件, ,mybatis-config.java,18,6/22/2020,(3) CRUD代码（Create）,public void testAdd() String resource = mybatis-config.xml; InputStream inputStre

18、am = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserMapper mapper = sqlSession.getMapper(IUserMapper.class); User user = new User(); user.setUsername(new);

19、 user.setPassword(new); int add = mapper.addUser(user); sqlSmit(); sqlSession.close(); ,获得映射接口,直接使用接口方法，无需接口实现类来完成,19,6/22/2020,(3) CRUD代码（Retrieve）,public void testGetAllUsers() String resource = mybatis-config.xml; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactor

20、y sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserMapper mapper = sqlSession.getMapper(IUserMapper.class); List listUsers= mapper.getAllUsers(); sqlSession.close(); System.out.println(listUsers); ,20,6/22/2020,(3) 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(