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mybatis 简介
mybatis的前身叫ibatis，本是apache的一个开源项目, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为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结果集的检索。mybatis使用简单的xml或注解用于配置和原始映射，将接口和java的pojos（plan old java objects，普通的java对象）映射成数据库中的记录。
下面分步骤给搭建介绍mybatis 环境搭建。
1)在工程下引入mybatis-3.4.1.jar包，再引入数据库（mysql,mssql..）包.
2)在src下新建一个配置文件conf.xml
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<?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>
<!-- 引入外部配置文件 -->
<properties resource="jdbc.properties" />
<!-- 配置mybatis运行环境 -->
<environments default="development">
<environment id="development">
<!-- type="jdbc" 代表使用jdbc的提交和回滚来管理事务 -->
<transactionmanager type="jdbc" />
<!-- mybatis提供了3种数据源类型，分别是：pooled,unpooled,jndi -->
<!-- pooled 表示支持jdbc数据源连接池 -->
<!-- unpooled 表示不支持数据源连接池 -->
<!-- jndi 表示支持外部数据源连接池 -->
<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="usermapper.xml"/>
</mappers>
</configuration>
这里是通过外部配置文件来存储数据库存信息的，所以加入一个jdbc.properties的数据库存信息
driver=com.microsoft.sqlserver.jdbc.sqlserverdriver url=jdbc:sqlserver://127.0.0.1;databasename=test username=sa password=123456
3)建立一个映射文件 usermapper.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="hw.com.ser.iuser">
<!-- 查询全部用户 -->
<select id="queryusers" resulttype="hw.com.pojo.user">
select * from ms_user
</select>
<selectid="queryuserbyid" resulttype="hw.com.pojo.user" parametertype="int">
select * from ms_user where id=#{id}
</select>
</mapper>
(这里要注意的是，namespace属性，因为，此实例是通过接口映射的方式，所以，namespace属性一点要写成接口的路径)附图：
4)建一个映射接口类
package hw.com.ser;
import java.util.list;
import hw.com.pojo.user;
public interface iuser {
public list<user> queryusers();
public user queryuserbyid(int id);
}
5）建立一个sqlsessionfactory
package hw.com.util;
import java.io.ioexception;
import java.io.inputstream;
import java.io.inputstreamreader;
import java.io.reader;
import java.util.properties;
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 = null;
private static final class class_lock = sqlsessionfactoryutil.class;
private sqlsessionfactoryutil() {
}
public static sqlsessionfactory initsqlsessionfactory() {
string resource = "conf.xml";
inputstream inputstream = null;
try {
inputstream = resources.getresourceasstream(resource);
} catch (ioexception e) {
e.printstacktrace();
}
synchronized (class_lock) {
if (sqlsessionfactory == null) {
sqlsessionfactory = new sqlsessionfactorybuilder().build(inputstream);
}
}
return sqlsessionfactory;
}
public static sqlsession opensqlsession(){
if(sqlsessionfactory==null){
initsqlsessionfactory();
}
return sqlsessionfactory.opensession();
}
}
6)建一个pojo
package hw.com.pojo;
import java.util.date;
public class user {
private string id;
private string username;
private string userpwd;
private int deptmentid;
private string usertruename;
private string email;
private int learncenterid;
private date createdate;
private date lastmodifydate;
private int userstatus;
public user() {
super();
// todo auto-generated constructor stub
}
public string getid() {
return id;
}
public void setid(string id) {
id = id;
}
public string getusername() {
return username;
}
public void setusername(string username) {
username = username;
}
public string getuserpwd() {
return userpwd;
}
public void setuserpwd(string userpwd) {
userpwd = userpwd;
}
public int getdeptmentid() {
return deptmentid;
}
public void setdeptmentid(int deptmentid) {
deptmentid = deptmentid;
}
public string getusertruename() {
return usertruename;
}
public void setusertruename(string usertruename) {
usertruename = usertruename;
}
public string getemail() {
return email;
}
public void setemail(string email) {
email = email;
}
public int getlearncenterid() {
return learncenterid;
}
public void setlearncenterid(int learncenterid) {
learncenterid = learncenterid;
}
public date getcreatedate() {
return createdate;
}
public void setcreatedate(date createdate) {
createdate = createdate;
}
public date getlastmodifydate() {
return lastmodifydate;
}
public void setlastmodifydate(date lastmodifydate) {
lastmodifydate = lastmodifydate;
}
public int getuserstatus() {
return userstatus;
}
public void setuserstatus(int userstatus) {
userstatus = userstatus;
}
@override
public string tostring() {
return "user [id=" + id + ", username=" + username + ", userpwd=" + userpwd + ", deptmentid=" + deptmentid
+ ", usertruename=" + usertruename + ", email=" + email + ", learncenterid=" + learncenterid
+ ", createdate=" + createdate + ", lastmodifydate=" + lastmodifydate + ", userstatus=" + userstatus
+ "]";
}
}
7) 在main方法下做测试
package hw.com.day1.main;
import java.util.list;
import org.apache.ibatis.session.sqlsession;
import hw.com.pojo.user;
import hw.com.ser.iuser;
import hw.com.util.sqlsessionfactoryutil;
public class usertest {
public static void main(string[] args) {
sqlsession sqlsession=null;
try {
sqlsession=sqlsessionfactoryutil.opensqlsession();
iuser iuser=sqlsession.getmapper(iuser.class);
list<user> users=iuser.queryusers();
if(users.size()>0){
for (user user : users) {
system.out.println(user.tostring());
}
}
} catch (exception e) {
e.printstacktrace();
}
}
}
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