什么是 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对结果集的检索。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。
MyBatis下载：https://github.com/mybatis/mybatis-3/releases
Mybatis实例：
对一个Student表的CRUD操作
在Src目录下建一个mybatis的xml配置文件mybatis.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> <properties resource="db.properties"></properties> <!-- 定义别名 --> <typeAliases> <!-- <typeAlias type="com.model.Student" alias="list"/> --> <package name="com.model"/><!-- 扫描 --> </typeAliases> <!-- mybatis的环境们 --> <environments default="test"> <environment id="test"> <!-- mybatis支持的事务: JDBC:数据源自己的事务管理 MANAGE(托管),不支持tomcat,一般用在大型的商业服务器,weblogic,jboss --> <transactionManager type="JDBC"> </transactionManager> <dataSource type="POOLED"> <property name="driver" value="oracle.jdbc.OracleDriver"></property> <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"></property> <property name="username" value="venus"></property> <property name="password" value="123"></property> </dataSource> </environment> </environments> <mappers> <mapper resource="com/dao/StudentMapper.xml"/> </mappers> </configuration>
定义Student mappers的StudentMapper.xml配置文件
<?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.dao.StudentMapper">
<resultMap type="Student" id="stu">
</resultMap>
<!-- 查所有数据 -->
<select id="list" resultType="student">
select * from student
</select>
<!-- 插入一条数据 -->
<insert id="add" parameterType="student">
insert into student values(#{sno},#{sname},#{ssex},sysdate,#{sclass})
</insert>
<!-- 修改一条数据 -->
<update id="update" parameterType="student">
update student s set s.sname=#{sname},s.ssex=#{ssex}
,s.sbirthday=sysdate,s.sclass=#{sclass} where s.sno=#{sno}
</update>
<!-- 删除一条数据 -->
<delete id="del" parameterType="String">
delete student s where s.sno=#{sno}
</delete>
<!-- 查符合条件的数据 -->
<select id="show" parameterType="Map" resultMap="stu">
select * from student s where s.sno like #{p1} and s.sname like #{p2}
</select>
</mapper>
配置文件实现了接口和SQL语句的映射关系。selectUsersByName采用了2种方式实现，注释掉的也是一种实现，采用resultMap可以把属性和数据库列名映射关系定义好，property为类的属性，column是表的列名，也可以是表列名的别名！
Student类的定义（可以用Hibernate自动生成Student实体类）：
package com.model;
// Generated 2017-4-19 11:51:47 by Hibernate Tools 5.2.0.CR1
import java.util.Date;
/**
* Student generated by hbm2java
*/
public class Student {
private String sno;
private String sname;
private String ssex;
private Date sbirthday;
private String sclass;
public Student() {
}
public Student(String sno, String sname, String ssex) {
this.sno = sno;
this.sname = sname;
this.ssex = ssex;
}
public Student(String sno, String sname, String ssex, Date sbirthday, String sclass) {
this.sno = sno;
this.sname = sname;
this.ssex = ssex;
this.sbirthday = sbirthday;
this.sclass = sclass;
}
public String getSno() {
return this.sno;
}
public void setSno(String sno) {
this.sno = sno;
}
public String getSname() {
return this.sname;
}
public void setSname(String sname) {
this.sname = sname;
}
public String getSsex() {
return this.ssex;
}
public void setSsex(String ssex) {
this.ssex = ssex;
}
public Date getSbirthday() {
return this.sbirthday;
}
public void setSbirthday(Date sbirthday) {
this.sbirthday = sbirthday;
}
public String getSclass() {
return this.sclass;
}
public void setSclass(String sclass) {
this.sclass = sclass;
}
}
为了方便写一个工具类 拿出session：
package com.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 MybatisUtil {
private static SqlSessionFactory ssf;
private static SqlSession ss;
public static SqlSession getSqlSession(){
InputStream in = null;
try {
in = Resources.getResourceAsStream("mybatis.xml");
ssf = new SqlSessionFactoryBuilder().build(in);
ss = ssf.openSession();
in.close();
} catch (IOException e) {
e.printStackTrace();
}
return ss;
}
}
测试类UserDao：
package com.util;
import static org.junit.Assert.*;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.crypto.Data;
import org.apache.ibatis.session.SqlSession;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.model.Student;
public class JUnit {
private SqlSession ss;
@Before
public void setUp() throws Exception {
ss = MybatisUtil.getSqlSession();
}
@After
public void tearDown() throws Exception {
ss.commit();
ss.close();
}
//查所有数据
public void test() {
List<Student> list = ss.selectList("com.dao.StudentMapper.list");
for(Student data : list){
System.out.println(data.getSname());
}
}
//增加一条数据
public void addTest(){
Student stu = new Student();
stu.setSno("120");
stu.setSname("张自忠");
stu.setSsex("男");
stu.setSclass("123");
ss.insert("com.dao.StudentMapper.add",stu);
}
//修改一条数据
public void updateTest(){
Student stu = new Student();
stu.setSno("120");
stu.setSname("张自恋");
stu.setSsex("男");
stu.setSclass("123");
ss.update("com.dao.StudentMapper.update",stu);
}
//删除一条数据
public void delTest(){
ss.delete("com.dao.StudentMapper.del","120");
}
//查符合条件的数据
@Test
public void show(){
Map<String, Object> map = new HashMap<String, Object>();
map.put("p1", "%7");
map.put("p2", "王%");
List<Student> list = ss.selectList("com.dao.StudentMapper.show",map);
for(Student data : list){
System.out.println(data.getSname());
}
}
}
PS：所用到的jar包就两个 一个是mybatis-3.4.4.jar 另外一个是数据库驱动包：ojdbc6.jar
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