步骤一：mybatis基本配置
1）创建Java项目，在lib下导入mybatis所需要的Jar包，包括链接mysql的mysql-connector-java-5.1.7-bin.jar。
2）在src目录下新建一个mybatis的配置文件
mybatis_conf.xml的内容如下
db.properties
jdbc.user = rootjdbc.password=123456jdbc.driverClass=com.mysql.jdbc.Driverjdbc.jdbcUrl=jdbc:mysql://127.0.0.1:3306/mybatis0814?useUnicode=true&characterEncoding=utf-8
步骤二：
1）新建表t_user，因为Mybatis不会自动创建数据表，和hibernate不一样，只专注sql
2）定义表的实体类，必须一一对应，否则需要在映射里面设置resultMap结果集映射
User
package com.feng.domain;import java.util.Date;public class User{ // 和表中的字段一一对应，否则需要在对应的Mapper配置文件用到resultMap结果集映射。 private Integer id; private String username; private int age; private Date registerDate; public User(){} public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public Date getRegisterDate() { return registerDate; } public void setRegisterDate(Date registerDate) { this.registerDate = registerDate; } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", age=" + age + ", registerDate=" + registerDate + "]"; } 3）在dao的包下，新建sql映射配置xml
UserMapper.xml 必须和实体类对应 格式：实体类+Mapper ，否则自动扫描不出来
insert into t_user(username,age,registerDate) values(#{username},#{age},#{registerDate}) delete from t_user where id = #{id} update t_user set username = #{username},age=#{age},registerDate=#{registerDate} where id = #{id}
这里注意一点，update、delete 返回值是：更新或删除的行数；无需指明resultClass；但如果有约束异常而删除失败，只能去捕捉异常。
insert，返回值是：新插入行的主键（primary key）；需要包含<selectKey>语句，才会返回主键，否则返回值为null。
4）操作接口
UserMapper.java
package com.feng.dao;import java.util.List;import java.util.Map;import com.feng.domain.User;public interface UserMapper { //增加一个用户 public void addUser(User user); //删除一个用户 public void deleteUser(Integer id); //修改用户信息 public void updateUser(User user); //得到一个用户 public User getUserById(Integer id); //得到所有用户 public List getAllUser(); // 多入参情况下用map public List getAllUser1(Map map);} 步骤三
1）新建测试类Test_Crud.java
package com.feng.test;import java.io.IOException;import java.io.InputStream;import java.util.Date;import java.util.HashMap;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 org.junit.Before;import org.junit.Test;import com.feng.domain.User;public class Test_Crud { private SqlSessionFactory sqlSessionFactory = null; @Before public void init() throws IOException { // 使用MyBatis提供的Resources类加载mybatis的配置文件（它也加载关联的映射文件） InputStream inputStream = Resources .getResourceAsStream("mybatis_conf.xml"); // 创建SqlSessionFactory工厂 sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } @Test public void addUser() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); User user = new User(); user.setAge(22); user.setRegisterDate(new Date()); user.setUsername("feng"); sqlSession.insert("com.feng.dao.UserMapper.addUser", user); sqlSession.commit(); System.out.println(user.getId()); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } } @Test public void deleteUser() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); sqlSession.delete("com.feng.dao.UserMapper.deleteUser", 2); sqlSession.commit(); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } } @Test public void updateUser() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); User user = new User(); user.setAge(22); user.setId(1); user.setRegisterDate(new Date()); user.setUsername("wei"); sqlSession.update("com.feng.dao.UserMapper.updateUser", user); sqlSession.commit(); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } } @Test public void getUserById() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); User user = sqlSession.selectOne( "com.feng.dao.UserMapper.getUserById", 1); System.out.println(user.toString()); sqlSession.commit(); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } } @Test public void getAllUser() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); java.util.List list = sqlSession .selectList("com.feng.dao.UserMapper.getAllUser"); for (User user : list) { System.out.println(user.toString()); } sqlSession.commit(); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } } @Test // 多入参情况下，用map public void getAllUser1() { // 创建并且打开sqlsession SqlSession sqlSession = null; try { sqlSession = sqlSessionFactory.openSession(); HashMap map = new HashMap (); map.put("age", 20); map.put("username", "feng"); java.util.List list = sqlSession.selectList( "com.feng.dao.UserMapper.getAllUser1", map); for (User user : list) { System.out.println(user.toString()); } sqlSession.commit(); } catch (Exception e) { e.printStackTrace(); } finally { if (sqlSession != null) { sqlSession.close(); } } }} 最后的结构图如下
