MyBatis——mybatis基本搭建

 

准备mysql数据库表user：

准备数据：

添加maven依赖：

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
	<dependency>
	    <groupId>mysql</groupId>
	    <artifactId>mysql-connector-java</artifactId>
	    <version>6.0.6</version>
	</dependency>
	  	
	<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
	<dependency>
	    <groupId>org.mybatis</groupId>
	    <artifactId>mybatis</artifactId>
	    <version>3.4.6</version>
	</dependency>

（一）使用xml

项目：

1.写User类。

/**
 * 2018年11月29日上午11:36:51
 */
package com.usexml.models;

/**
 * @author XWF
 *
 */
public class User {
	private int id;
	private String name;
	private String dept;
	private String phone;
	private String website;
	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 getDept() {
		return dept;
	}
	public void setDept(String dept) {
		this.dept = dept;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getWebsite() {
		return website;
	}
	public void setWebsite(String website) {
		this.website = website;
	}
}

2.mybatis配置文件mybatis-config.xml和数据库配置mysql-config.properties。

<?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>
	<properties resource="com/usexml/config/mysql-config.properties"></properties>
	
	<typeAliases>
		<typeAlias alias="User" type="com.usexml.models.User" />
	</typeAliases>
	
	<environments default="development">
	    <environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">  
                <!-- <property name="driver" value="com.mysql.jdbc.Driver" />
			    <property name="url" value="jdbc:mysql://192.168.1.244:3306/test?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC" /> &符号要用&amp;转
			    <property name="username" value="root" />
			    <property name="password" value="root" /> -->
			    <property name="driver" value="${driver}"/>
			    <property name="url" value="${url}"/>
			    <property name="username" value="${username}"/>
			    <property name="password" value="${password}"/>
            </dataSource>
		</environment>
	</environments>

	<!-- 配置mapper映射xml -->
	<mappers>
	     <mapper resource="com/usexml/mappers/User.xml" />
	</mappers>
</configuration>

 注：mybatis配置文件里数据库url项如果直接配置在xml里需要把‘&’符号用&转义。

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://192.168.1.244:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
username=root
password=root

3.映射文件User.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.mybatis.UserMapper">
	<select id="GetUserByID" parameterType="int" resultType="User">
		select * from `user` where id = #{id}
    </select>
</mapper>

resultType对应mybatis配置文件的alias值；

4.测试Demo：

/**
 * 2018年11月29日下午2:56:45
 */
package com.usexml;

import java.io.IOException;

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 com.usexml.models.User;

/**
 * @author XWF
 *
 */
public class MainXmlTest {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("com/usexml/config/mybatis-config.xml"));
		
		SqlSession session = sqlSessionFactory.openSession();
		User u = session.selectOne("com.mybatis.UserMapper.GetUserByID",1);//通过xml里定义的namespace和id使用
		
		if(null != u) {
			System.out.println(u.getId());
			System.out.println(u.getName());
			System.out.println(u.getDept());
			System.out.println(u.getWebsite());
			System.out.println(u.getPhone());
		}
		session.close();
	}

}

结果：

（二）使用注解

项目：

1.User类同上。

2.mybatis配置文件mybatis-config.xml和数据库配置文件mysql-config.properties。

<?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>
	<properties resource="com/useannotation/config/mysql-config.properties"></properties>
	
	<typeAliases>
		<typeAlias alias="User" type="com.useannotation.models.User" />
	</typeAliases>
	
	<environments default="development">
	    <environment id="development">
			<transactionManager type="JDBC" />
			<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>

</configuration>

mybatis配置里去掉了mappers配置。

mysql-config.properties同上。

3.使用注解接口。

/**
 * 2018年11月29日下午3:27:38
 */
package com.useannotation.dao;

import org.apache.ibatis.annotations.Select;

import com.useannotation.models.User;

/**
 * @author XWF
 *
 */
public interface IUser {

	@Select("select * from user where id=#{id}")
	public User getUserById(int id);
}

4测试Demo：

/**
 * 2018年11月29日下午3:27:18
 */
package com.useannotation;

import java.io.IOException;

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 com.useannotation.dao.IUser;
import com.useannotation.models.User;

/**
 * @author XWF
 *
 */
public class MainAnnotationTest {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("com/usexml/config/mybatis-config.xml"));
		sqlSessionFactory.getConfiguration().addMapper(IUser.class);//添加mapper
		SqlSession session = sqlSessionFactory.openSession();
		IUser iuser = session.getMapper(IUser.class);//通过接口
		User u = iuser.getUserById(1);
		if(null != u) {
			System.out.println(u.getId());
			System.out.println(u.getName());
			System.out.println(u.getDept());
			System.out.println(u.getWebsite());
			System.out.println(u.getPhone());
		}
		session.close();
	}

}

sqlSessionFactory配置里addMapper添加映射接口。

结果同上。

（三）使用xml和接口

项目：

1.User类同上。

2.mybatis配置文件mybatis.xml和数据库配置文件mysql-config.properties。

<?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>
	<properties resource="com/xmlandannotation/config/mysql-config.properties"></properties>
	
	<typeAliases>
		<typeAlias alias="User" type="com.xmlandannotation.models.User" />
	</typeAliases>
	
	<environments default="development">
	    <environment id="development">
			<transactionManager type="JDBC" />
			<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="com/xmlandannotation/mappers/User.xml" />
	</mappers>
</configuration>

mysql-config.properties同上。

3.接口IUser.java。

/**
 * 2018年11月29日下午4:09:27
 */
package com.xmlandannotation.dao;

import java.util.List;

import com.xmlandannotation.models.User;

/**
 * @author XWF
 *
 */
public interface IUser {
	//方法名跟xml里的id一直
	public void insertUser(User u);
	public void deleteUser(int idd);//参数名跟xml里的#{一致}
	public void updateUser(User user);
	public User selectUserById(int id);
	public List<User> getUserList();
}

4.User.xml文件。

<?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.xmlandannotation.dao.IUser">
	<insert id="insertUser" useGeneratedKeys="true" keyProperty="id" parameterType="User">
		INSERT INTO user(name,dept,website,phone)
		VALUES(#{name},#{dept},#{website},#{phone})
	</insert>
	
	<delete id="deleteUser" parameterType="int">
		DELETE FROM user WHERE id = #{idd}
	</delete>
	
	<update id="updateUser" parameterType="User">
		UPDATE user 
		SET name=#{name},dept=#{dept},website=#{website},phone=#{phone}
		WHERE id=#{id}
	</update>
	
	<select id="selectUserById" parameterType="int" resultType="User">
		SELECT * FROM user
		WHERE id=#{id}
	</select>
	
	<select id="getUserList" resultType="User">
		SELECT * FROM user
	</select>
</mapper>

namespace是接口路径。标签的id属性要跟接口方法一致。

insert语句里useGeneratedKeys="true" keyProperty="id"表示插入后得到主键。

5.测试Demo：

/**
 * 2018年11月29日下午4:06:27
 */
package com.xmlandannotation;

import java.io.IOException;
import java.util.List;

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 com.xmlandannotation.dao.IUser;
import com.xmlandannotation.models.User;

/**
 * @author XWF
 *
 */
public class MainTest {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("com/xmlandannotation/config/mybatis.xml"));
		
		SqlSession session = sqlSessionFactory.openSession();
		IUser userMapper = session.getMapper(IUser.class);
		//增
		User u = new User();
		u.setName("Jerry");
		u.setDept("dept");
		u.setWebsite("http://www.baidu.com");
		u.setPhone("12367896789");
		userMapper.insertUser(u);
		session.commit();//提交
		System.out.println("新增的id："+u.getId());
		//查
		List<User> ulist = userMapper.getUserList();
		for(User user:ulist) {
			System.out.println("----"+user.getId()+","+user.getName()+","+user.getDept()+","+user.getWebsite()+","+user.getPhone());
		}
		
		User u2 = userMapper.selectUserById(1);
		System.out.println(u2.getName());
		//改
		u2.setName("Little Tom");
		userMapper.updateUser(u2);
		session.commit();//提交
		//删
		userMapper.deleteUser(u.getId());
		session.commit();//提交
		session.close();
	}

}

注：插入、修改、删除操作需要commit提交事务到数据库。

结果：

 

参考：https://www.yiibai.com/mybatis