使用MyBatis搭建一个访问mysql数据库的简单示例

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 Old Java Objects，普通的Java对象）映射成数据库中的记录。

框架整体结构图：



关键代码介绍

1.ICatagoryOperation接口

public interface ICatagoryOperation {
void inserteCatagory(Catagory catagory);

Catagory getCatagorybyID(int id);
}

2.Catagory类

public class Catagory {
private int id;
private String name;

private String description;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getDescription() {
return description;
}

public void setDescription(String description) {
this.description = description;
}

@Override
public String toString() {
return String.format("id:%d,name:%s,description:%s", id, name, description);
}
}

3.MyBatisUtils类

public class MyBatisUtils {
private static final String CONFIG_PATH = "config/mybatis_config.xml";

/*
* 获取数据库访问链接
*/
public static SqlSession getSqlSession() {
SqlSession session = null;
try {
InputStream stream = Resources.getResourceAsStream(CONFIG_PATH);
// 可以根据配置的相应环境读取相应的数据库环境
// SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(
// stream, "development");
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(stream);
session = factory.openSession();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return session;
}

/*
* 获取数据库访问链接
*/
public static void closeSession(SqlSession session) {
session.close();
}
}

4.CatagoryMapper.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="com.franson.study.interfaces.ICatagoryOperation">
<!-- 此处的resultType就是对应刚刚你在typeAlias节点里面规定的别名 -->
<select id="inserteCatagory" parameterType="Catagory">
insert into tb_catagories(name,description) values(#{name},#{description})
</select>
<select id="getCatagorybyID" resultType="Catagory" parameterType="java.lang.Integer">
select * from tb_catagories where id=#{id}
</select>
</mapper>

5.mybatis_config.xml,核心配置文件

<?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>
<typeAliases>
<typeAlias type="com.franson.study.model.Catagory" alias="Catagory" />
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<!-- ?useUnicode=true&characterEncoding=utf8为了支持中文数据的写入 -->
<property name="url"
value="jdbc:mysql://127.0.0.1:3306/db_catagory?useUnicode=true&characterEncoding=utf8" />
<property name="username" value="root" />
<property name="password" value="123456" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/CatagoryMapper.xml" />
</mappers>
</configuration>

6.TestMybatis测试入口类

public class TestMybatis {

public static void main(String[] args) {
addTest();
getTest();
}

/*
* 添加Catagory
*/
static void addTest() {
SqlSession sqlSession = MyBatisUtils.getSqlSession();
ICatagoryOperation catagoryOperation = sqlSession.getMapper(ICatagoryOperation.class);
Catagory item = new Catagory();
item.setName("sql server");
item.setDescription("sql server类");
int result = catagoryOperation.inserteCatagory(item);
if (result > 0) {
sqlSession.commit();
System.out.println("添加成功");
} else
sqlSession.rollback();
MyBatisUtils.closeSession(sqlSession);
}

/*
* 根据ID获取Catagory
*/
static void getTest() {
SqlSession sqlSession = MyBatisUtils.getSqlSession();
ICatagoryOperation catagoryOperation = sqlSession.getMapper(ICatagoryOperation.class);
System.out.println(catagoryOperation.getCatagorybyID(3).toString());
MyBatisUtils.closeSession(sqlSession);
}
}

7.测试运行结果