MyBatis 简介
MyBatis的前身叫iBatis，本是apache的一个开源项目, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为MyBatis。
MyBatis是支持普通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结果集的检索。MyBatis使用简单的XML或注解用于配置和原始映射，将接口和Java的POJOs（Plan Old Java Objects，普通的Java对象）映射成数据库中的记录。
下面分步骤给搭建介绍mybatis 环境搭建。
1)在工程下引入mybatis-3.4.1.jar包，再引入数据库（mysql,mssql..）包.
2)在src下新建一个配置文件conf.xml
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><!-- 引入外部配置文件 --> <properties resource="jdbc.properties" /> <!-- 配置mybatis运行环境 --> <environments default="development"> <environment id="development"> <!-- type="JDBC" 代表使用JDBC的提交和回滚来管理事务 --> <transactionManager type="JDBC" /> <!-- mybatis提供了3种数据源类型，分别是：POOLED,UNPOOLED,JNDI --> <!-- POOLED 表示支持JDBC数据源连接池 --> <!-- UNPOOLED 表示不支持数据源连接池 --> <!-- JNDI 表示支持外部数据源连接池 --> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="userMapper.xml"/> </mappers> </configuration>这里是通过外部配置文件来存储数据库存信息的，所以加入一个jdbc.properties的数据库存信息
driver=com.microsoft.sqlserver.jdbc.SQLServerDriverurl=jdbc:sqlserver://127.0.0.1;databaseName=testusername=sapassword=123456
3)建立一个映射文件 userMapper.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="hw.com.ser.IUser"> <!-- 查询全部用户 --> <select id="queryUsers" resultType="hw.com.pojo.User"> select * from MS_User </select> <selectid="queryUserById" resultType="hw.com.pojo.User" parameterType="int"> Select * From Ms_User Where id=#{id} </select> </mapper>(这里要注意的是，namespace属性，因为，此实例是通过接口映射的方式，所以，namespace属性一点要写成接口的路径)附图：
4)建一个映射接口类
package hw.com.ser;import java.util.List;import hw.com.pojo.User;public interface IUser { public List<User> queryUsers(); public User queryUserById(int id);}5）建立一个SqlSessionFactory
package hw.com.util;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.Reader;import java.util.Properties;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class SqlSessionFactoryUtil { private static SqlSessionFactory sqlSessionFactory = null; private static final Class CLASS_LOCK = SqlSessionFactoryUtil.class; private SqlSessionFactoryUtil() { } public static SqlSessionFactory initSqlSessionFactory() { String resource = "conf.xml"; InputStream inputStream = null; try { inputStream = Resources.getResourceAsStream(resource); } catch (IOException e) { e.printStackTrace(); } synchronized (CLASS_LOCK) { if (sqlSessionFactory == null) { sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } } return sqlSessionFactory; } public static SqlSession openSqlSession(){ if(sqlSessionFactory==null){ initSqlSessionFactory(); } return sqlSessionFactory.openSession(); }}6)建一个pojo
package hw.com.pojo;import java.util.Date;public class User { private String Id; private String UserName; private String UserPwd; private int DeptmentId; private String UserTrueName; private String Email; private int LearnCenterId; private Date CreateDate; private Date LastModifyDate; private int UserStatus; public User() { super(); // TODO Auto-generated constructor stub } public String getId() { return Id; } public void setId(String id) { Id = id; } public String getUserName() { return UserName; } public void setUserName(String userName) { UserName = userName; } public String getUserPwd() { return UserPwd; } public void setUserPwd(String userPwd) { UserPwd = userPwd; } public int getDeptmentId() { return DeptmentId; } public void setDeptmentId(int deptmentId) { DeptmentId = deptmentId; } public String getUserTrueName() { return UserTrueName; } public void setUserTrueName(String userTrueName) { UserTrueName = userTrueName; } public String getEmail() { return Email; } public void setEmail(String email) { Email = email; } public int getLearnCenterId() { return LearnCenterId; } public void setLearnCenterId(int learnCenterId) { LearnCenterId = learnCenterId; } public Date getCreateDate() { return CreateDate; } public void setCreateDate(Date createDate) { CreateDate = createDate; } public Date getLastModifyDate() { return LastModifyDate; } public void setLastModifyDate(Date lastModifyDate) { LastModifyDate = lastModifyDate; } public int getUserStatus() { return UserStatus; } public void setUserStatus(int userStatus) { UserStatus = userStatus; } @Override public String toString() { return "User [Id=" + Id + ", UserName=" + UserName + ", UserPwd=" + UserPwd + ", DeptmentId=" + DeptmentId + ", UserTrueName=" + UserTrueName + ", Email=" + Email + ", LearnCenterId=" + LearnCenterId + ", CreateDate=" + CreateDate + ", LastModifyDate=" + LastModifyDate + ", UserStatus=" + UserStatus + "]"; }}7) 在main方法下做测试
package hw.com.Day1.main;import java.util.List;import org.apache.ibatis.session.SqlSession;import hw.com.pojo.User;import hw.com.ser.IUser;import hw.com.util.SqlSessionFactoryUtil;public class UserTest { public static void main(String[] args) { SqlSession sqlSession=null; try { sqlSession=SqlSessionFactoryUtil.openSqlSession(); IUser iUser=sqlSession.getMapper(IUser.class); List<User> users=iUser.queryUsers(); if(users.size()>0){ for (User user : users) { System.out.println(user.toString()); } } } catch (Exception e) { e.printStackTrace(); } }}