mybatis简介
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：
mybatis实例
对一个user表的crud操作：
user表：
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-- ----------------------------
-- table structure for `user`
-- ----------------------------
drop table if exists `user`;
create table `user` (
`id` int(11) not null auto_increment,
`username` varchar(50) default null,
`userage` int(11) default null,
`useraddress` varchar(200) default null,
primary key (`id`)
) engine=innodb auto_increment=6 default charset=utf8;
-- ----------------------------
-- records of user
-- ----------------------------
insert into `user` values ('1', 'summer', '30', 'shanghai');
insert into `user` values ('2', 'test2', '22', 'suzhou');
insert into `user` values ('3', 'test1', '29', 'some place');
insert into `user` values ('4', 'lu', '28', 'some place');
insert into `user` values ('5', 'xiaoxun', '27', 'nanjing');
在src目录下建一个mybatis的xml配置文件configuration.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>
<!-- mybatis别名定义 -->
<typealiases>
<typealias alias="user" type="com.mybatis.test.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://127.0.0.1:3306/mybatis" />
<property name="username" value="root"/>
<property name="password" value="admin"/>
</datasource>
</environment>
</environments>
<!-- mybatis的mapper文件，每个xml配置文件对应一个接口 -->
<mappers>
<mapper resource="com/mybatis/test/user.xml"/>
</mappers>
</configuration>
定义user mappers的user.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.mybatis.test.iuseroperation">
<!-- select语句 -->
<select id="selectuserbyid" parametertype="int" resulttype="user">
select * from `user` where user.id = #{id}
</select>
<!-- 定义的resultmap，可以解决类的属性名和数据库列名不一致的问题-->
<!-- <resultmap type="user" id="userresultmap">
<id property="id" column="user_id" />
<result property="username" column="user_username" />
<result property="userage" column="user_userage" />
<result property="useraddress" column="user_useraddress" />
</resultmap> -->
<!-- 返回list的select语句，注意 resultmap的值是指向前面定义好的 -->
<!-- <select id="selectusersbyname" parametertype="string" resultmap="userresultmap">
select * from user where user.username = #{username}
</select> -->
<select id="selectusersbyname" parametertype="string" resulttype="user">
select * from user where user.username = #{username}
</select>
<!--执行增加操作的sql语句。id和parametertype分别与iuseroperation接口中的adduser方法的名字和参数类型一致。
usegeneratedkeys设置为"true"表明要mybatis获取由数据库自动生成的主键；keyproperty="id"指定把获取到的主键值注入到user的id属性-->
<insert id="adduser" parametertype="user"
usegeneratedkeys="true" keyproperty="id">
insert into user(username,userage,useraddress)
values(#{username},#{userage},#{useraddress})
</insert>
<update id="updateuser" parametertype="user" >
update user set username=#{username},userage=#{userage},useraddress=#{useraddress} where id=#{id}
</update>
<delete id="deleteuser" parametertype="int">
delete from user where id=#{id}
</delete>
</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！
user类的定义：
package com.mybatis.test;
public class user {
private int id;
private string username;
private int userage;
private string useraddress;
public int getid() {
return id;
}
public void setid(int id) {
this.id = id;
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public int getuserage() {
return userage;
}
public void setuserage(int userage) {
this.userage = userage;
}
public string getuseraddress() {
return useraddress;
}
public void setuseraddress(string useraddress) {
this.useraddress = useraddress;
}
@override
public string tostring(){
return this.username+" "+this.userage+" "+this.useraddress;
}
}
iuseroperaton定义：
package com.mybatis.test;
import java.util.list;
public interface iuseroperation {
public user selectuserbyid(int id);
public list<user> selectusersbyname(string username);
public void adduser(user user);
public void updateuser(user user);
public void deleteuser(int id);
}
iuseroperation为操作接口，函数名和mybatis的xml配置文件中的操作id名对应。
测试类test：
package com.mybatis.test;
import java.io.reader;
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;
public class test {
private static sqlsessionfactory sqlsessionfactory;
private static reader reader;
static {
try {
reader = resources.getresourceasreader("configuration.xml");
sqlsessionfactory = new sqlsessionfactorybuilder().build(reader);
} catch (exception e) {
e.printstacktrace();
}
}
public static sqlsessionfactory getsession() {
return sqlsessionfactory;
}
public void getuserbyid(int userid) {
sqlsession session = sqlsessionfactory.opensession();
try {
iuseroperation useroperation = session
.getmapper(iuseroperation.class);
user user = useroperation.selectuserbyid(userid);
if (user != null) {
system.out.println(user.getid() + ":" + user.getusername()
+ ":" + user.getuseraddress());
}
} finally {
session.close();
}
}
public void getuserlist(string username) {
sqlsession session = sqlsessionfactory.opensession();
try {
iuseroperation useroperation = session
.getmapper(iuseroperation.class);
list<user> users = useroperation.selectusersbyname(username);
for (user user : users) {
system.out.println(user.getid() + ":" + user.getusername()
+ ":" + user.getuseraddress());
}
} finally {
session.close();
}
}
/**
* 增加后要commit
*/
public void adduser() {
user user = new user();
user.setuseraddress("place");
user.setusername("test_add");
user.setuserage(30);
sqlsession session = sqlsessionfactory.opensession();
try {
iuseroperation useroperation = session
.getmapper(iuseroperation.class);
useroperation.adduser(user);
session.commit();
system.out.println("新增用户id：" + user.getid());
} finally {
session.close();
}
}
/**
* 修改后要commit
*/
public void updateuser() {
sqlsession session = sqlsessionfactory.opensession();
try {
iuseroperation useroperation = session
.getmapper(iuseroperation.class);
user user = useroperation.selectuserbyid(1);
if (user != null) {
user.setuseraddress("a new place");
useroperation.updateuser(user);
session.commit();
}
} finally {
session.close();
}
}
/**
* 删除后要commit.
*
* @param id
*/
public void deleteuser(int id) {
sqlsession session = sqlsessionfactory.opensession();
try {
iuseroperation useroperation = session
.getmapper(iuseroperation.class);
useroperation.deleteuser(id);
session.commit();
} finally {
session.close();
}
}
public static void main(string[] args) {
try {
test test = new test();
// test.getuserbyid(1);
// test.getuserlist("test1");
// test.adduser();
// test.updateuser();
// test.deleteuser(6);
} catch (exception e) {
system.out.println(e.getmessage());
}
}
}
以上所述是小编给大家介绍的mybatis实现增删改查（crud）实例代码 ，希望对大家有所帮助
如对本文有疑问， 点击进行留言回复！！
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