Mybatis 入门之MyBatis环境搭建(第一篇)

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.SQLServerDriver
url=jdbc:sqlserver://127.0.0.1;databaseName=test
username=sa
password=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();
}
}
}

来源：http://www.cnblogs.com/lijianhua/archive/2016/12/20/6201158.html