目录
第二步,导入mybatis-config.xml的配置文件:
Mybatis简介:
MyBatis 是一款优秀的持久层框架,它支持定制化 SQL、存储过程以及高级映射。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以使用简单的 XML 或注解来配置和映射原生信息,将接口和 Java 的 POJOs(Plain Old Java Objects,普通的 Java对象)映射成数据库中的记录。
iBATIS一词来源于“internet”和“abatis”的组合,是一个基于Java的持久层框架。
所谓“持久层”,也就是在系统逻辑层面上,专著于实现数据持久化的一个相对独立的领域(Domain),是把数据保存到可掉电式存储设备中。持久层是负责向(或者从)一个或者多个数据存储器中存储(或者获取)数据的一组类和组件。
实例:
下面开始新建一个mybatis的实例:
新建一个java项目:最终的结构目录如下
第一步,创建数据库表:
编写对应于数据库中学生的对象类:
package com.java1234.model;
public class Student {
private Integer id;
private String name;
private Integer age;
public Student() {
super();
}
public Student(String name, Integer age) {
super();
this.name = name;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
第二步,导入mybatis-config.xml的配置文件:
<?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>
<properties resource="jdbc.properties"/>
<typeAliases>
<typeAlias alias="Student" type="com.java1234.model.Student"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/java1234/mappers/StudentMapper.xml" />
</mappers>
</configuration>
改进后的Mybatis配置文件如下:
<?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="jdbc.properties"/>
<!--
<typeAliases>
<typeAlias alias="Student" type="com.java1234.model.Student"/>
</typeAliases>
这是对数量不多的类进行配置的,不适用于大量的类
-->
<typeAliases>
<package name="com.java1234.model"></package>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED"> <!-- 数据库连接池 -->
<property name="driver" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- <mapper resource="com/java1234/mappers/StudentMapper.xml" /> -->
<!-- <mapper class="com.java1234.mappers.StudentMapper/> 这两种都是用于数量不多的配置-->
<package name="com.java1234.mappers"/>
</mappers>
</configuration>
其中引用到的jdbc.properties文件如下:
jdbc.driverClassName=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?useSSL=false&serverTimezone=GMT
jdbc.username=root
jdbc.password=000
第三步,导入对应jar包:
第四步,写对应的mapper文件:
StudentMapper.java
package com.java1234.mappers;
import com.java1234.model.Student;
public interface StudentMapper {
public int add(Student student);
}
StudentMapper.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.java1234.mappers.StudentMapper">
<insert id="add" parameterType="Student" >
insert into t_student values(null,#{name},#{age})
</insert>
</mapper>
第五步:生成session工厂
SqlSessionFactoryUtil.java
package com.java1234.util;
import java.io.IOException;
import java.io.InputStream;
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;
public static SqlSessionFactory getSessionFactory() {
if(sqlSessionFactory==null) {
InputStream inputStream=null;
try {
inputStream=Resources.getResourceAsStream("mybatis-config.xml");
sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
return sqlSessionFactory;
}
public static SqlSession openSession() {
return getSessionFactory().openSession();
}
}
最后一步,测试:
package com.java1234.service;
import org.apache.ibatis.session.SqlSession;
import com.java1234.mappers.StudentMapper;
import com.java1234.model.Student;
import com.java1234.util.SqlSessionFactoryUtil;
public class StudentTest {
public static void main(String[] args) {
SqlSession sqlSession=SqlSessionFactoryUtil.openSession();
StudentMapper studentMapper =sqlSession.getMapper(StudentMapper.class);
Student student=new Student("孙悟空",500);
int result=studentMapper.add(student);
sqlSession.commit();
if(result>0) {
System.out.println("添加学生信息成功");
}else {
System.out.println("添加学生失败");
}
}
}
运行结果:
查看数据库: