mybatis3.3+struts2.3.24+mysql5.1.22开发环境搭建图文教程

一、新建web工程，并在lib目录下添加jar包
 主要jar包：struts2相关包，mybatis3.3相关包，mysql-connector-java-5.1.22-bin.jar， gson-2.1.jar 

二、配置web.xml，添加一个过滤器strutsprepareandexecutefilter，处理所有*.action请求； 

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemalocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="webapp_id" version="3.0">
 <display-name>ms</display-name>
 <filter>
 <filter-name>struts2</filter-name>
 <filter-class>org.apache.struts2.dispatcher.ng.filter.strutsprepareandexecutefilter</filter-class>
 </filter>

 <filter-mapping>
 <filter-name>struts2</filter-name>
 <url-pattern>*.action</url-pattern>
 </filter-mapping>

 <welcome-file-list>
 <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>

</web-app>

查看该过滤器dofilter源码，主要做以下几件事：
 1、判断是否设置了struts排除的url（struts.action.excludepattern，通过正则表达式匹配），如果有且当前路径符合规则，则将请求转发给过滤器链上下一个对象，不交给struts2处理 

if (excludedpatterns != null && prepare.isurlexcluded(request, excludedpatterns)) {
 chain.dofilter(request, response);
} 

2、查找actionmapping：通过prepareoperations的findactionmapping方法查找，如果没找到，则将请求转发给过滤器链上下一个对象，不交给struts2处理；如果找到actionmapping，则调用executeoperations的executeaction方法，开始执行action；下图是根据url找到actionmapping的情况； 

三、配置struts.xml文件,该demo主要演示向前端传json格式数据，result type设成json格式，当然也可以设成其它的；  

<?xml version="1.0" encoding="utf-8" ?>
<!doctype struts public
 "-//apache software foundation//dtd struts configuration 2.3//en"
 "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

 <constant name="struts.devmode" value="false" />

 <package name="default" extends="struts-default,json-default">
 
  <global-results>
  <result type="json">
  <param name="root">json</param>
  <param name="contenttype">text/html</param>
  </result>
  </global-results>

  <action name="adduser" class="ms.action.useraction" method="adduser">
   <result>.</result>
  </action>
  
  <action name="queryalluser" class="ms.action.useraction" method="queryalluser">
  <result>.</result>
 </action>
 
 </package>

 <!-- add packages here -->

</struts>

四、配置mybatis.xml和usermapper.xml,
 配置cacheenabled为true, 开启二级缓存；
 配置datasource相关信息: type为pooled-连接池形式，poolmaximumactiveconnections – 在任意时间存在的活动(也就是正在使用)连接的数量，默认值:10。
 配置实体类映射mappers             //<mapper resource="ms/model/usermapper.xml"/> 

<?xml version="1.0" encoding="utf-8"?>
<!doctype configuration public "-//mybatis.org//dtd sql map config 3.0//en" 
 "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>


 <settings>
 <!--开启二级缓存-->
 <setting name="cacheenabled" value="true"/>
 </settings>


 <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://localhost:3306/demo" />
   <property name="username" value="root" />
   <property name="password" value="admin" />
   <property name="poolmaximumactiveconnections" value="10" />
   <property name="poolpingenabled" value="true"/>
   <property name="poolpingquery" value="select 1 as poolpingquery"/>
  </datasource>
 </environment>
 </environments>
 <mappers>
  <mapper resource="ms/model/usermapper.xml"/>
 </mappers>
</configuration>

配置usermapper.xml，配置缓存为ehcache及相关参数，记得实体类要实现serializable接口 

<?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="usermapper">
 
 <!-- 默认的cache <cache />-->
 <!-- 使用ehcache缓存 -->
 <cache type="org.mybatis.caches.ehcache.loggingehcache" >
 <property name="timetoidleseconds" value="3600"/><!--1 hour 缓存自创建日期起至失效时的间隔时间-->
 <property name="timetoliveseconds" value="3600"/><!--1 hour 缓存创建以后，最后一次访问缓存的日期至失效之时的时间间隔-->
 <property name="maxentrieslocalheap" value="1000"/>
 <property name="maxentrieslocaldisk" value="10000000"/>
 <property name="memorystoreevictionpolicy" value="lru"/> 
 </cache>

 <!-- 新增-->
 <insert id="saveuser" parametertype="ms.model.user">
 insert into user(
 account, 
 name, 
 address
 ) values (
 #{account}, 
 #{name}, 
 #{address}
 )
 </insert>
 
 <select id="queryalluser" resulttype="ms.model.user">
 select u.id,
  u.account,
  u.name,
  u.address
 from user u
 </select>

 
</mapper>

五、关键代码
 dao层：
 首先建一个类，用于获取sqlsessionfactory，设计成单例模式； 

package ms.dao.base;

import java.io.ioexception;

import org.apache.ibatis.io.resources;
import org.apache.ibatis.session.sqlsessionfactory;
import org.apache.ibatis.session.sqlsessionfactorybuilder;
import org.apache.log4j.logger;

public class mysessionfactory {

 private static sqlsessionfactory sessionfactory;
 private mysessionfactory(){
 
 }
 
 public static synchronized sqlsessionfactory getsqlsessionfactory(){
 if(sessionfactory == null){
  try {
  sessionfactory = new sqlsessionfactorybuilder().build(resources.getresourceasreader("mybatis-config.xml"));
  return sessionfactory;
  } catch (ioexception e) {
  logger.getlogger(mysessionfactory.class).error("getsqlsessionfactory error.");
  e.printstacktrace();
  return null;
  }
 }else{
  return sessionfactory;
 }
 }
 
}

接下来是userdao，通过opensession获取sqlsession,注意这里是可以通过sqlsession的commit和rollback进行事务控制的，当然如果本来就一条sql操作，也就没什么事务控制可言了（本例子只是demo）； 

package ms.dao;

import java.util.arraylist;
import java.util.list;

import org.apache.ibatis.session.sqlsession;

import ms.dao.base.mysessionfactory;
import ms.model.user;

public class userdao {
 
 public void add(user user) throws exception{
 sqlsession session = mysessionfactory.getsqlsessionfactory().opensession();
 try {
  
  string statement = "usermapper.saveuser";
  session.insert(statement, user);
  session.commit(true);
  
 } catch (exception e) {
  session.rollback(true);
  e.printstacktrace();
  
  throw new exception("error in add method");
 } finally {
  session.close();
 }
  
 }
 
 public list<user> queryalluser() throws exception{
 sqlsession session = mysessionfactory.getsqlsessionfactory().opensession();
 list<user> users = new arraylist<user>();
 try{
  string statement = "usermapper.queryalluser";
  users = session.selectlist(statement,1);
  session.commit(true);
  
 } catch (exception e) {
  session.rollback(true);
  e.printstacktrace();
  throw new exception("error in queryalluser method");
 } finally {
  session.close();
 }
 
 return users;
 }
}

service层：略
 model：略
 action层：
 转成json格式数据返回给前端； 

package ms.action;

import java.io.printwriter;
import java.util.list;

import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;

import ms.model.user;
import ms.service.userservice;

import org.apache.log4j.logger;
import org.apache.struts2.servletactioncontext;

import com.google.gson.gson;

public class useraction {
 logger logger = logger.getlogger(useraction.class);
 private userservice userservice = new userservice();
 public void adduser(){
 printwriter out = null;
 try{
  httpservletrequest request = servletactioncontext.getrequest();
  httpservletresponse response = servletactioncontext.getresponse();
  response.setcontenttype("text/html;charset=utf-8");
  string account = request.getparameter("account");
  string name = request.getparameter("name");
  string address = request.getparameter("address"); 
  user user = new user();
  user.setaccount(account);
  user.setaddress(address);
  user.setname(name);
  userservice.add(user);
  out = response.getwriter();
  out.write(new gson().tojson("success"));
 }catch(exception e){
  e.printstacktrace();
  logger.error(e.getmessage());
  if(out != null)
  out.write(new gson().tojson("fail"));
 }finally{
  out.flush();
  out.close();
 }
 
 }
 
 
 public void queryalluser(){
 printwriter out = null;
 try {
  httpservletresponse response = servletactioncontext.getresponse();
  response.setcontenttype("text/html;charset=utf-8");
 
  gson gson = new gson();
  list<user> userlist= userservice.queryalluser();
  string gsonstr = gson.tojson(userlist);
  
  out = response.getwriter();
  out.write(gsonstr);
 } catch (exception e) {
  e.printstacktrace();
  logger.error(e.getmessage());
  if(out != null)
  out.write(new gson().tojson("fail"));
 }finally{
  out.flush();
  out.close();
 }
 }
}

前端代码： 

<%@ page language="java" contenttype="text/html; charset=utf-8"
 pageencoding="utf-8"%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>insert title here</title>
<style>
.mt20{
 margin-top: 20px;
}
</style>
</head>
<body>

<div style="text-align: center;">
 <div class="mt20"><label>账号：</label><input id="account" type="text"/></div>
 <div class="mt20"><label>姓名：</label><input id="name" type="text"/></div>
 <div class="mt20"><label>地址：</label><input id="address" type="text"/></div>
 <div class="mt20"><button id="adduser" >添加</button></div>
</div>

<h3>用户列表:</h3>
<ul id="userlist">
</ul>

<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>

<script>
 $(function() {
 $.ajax({
  url : 'queryalluser.action',
  type : 'post',
  datatype : 'json',
  success : function(data) {
  try {
  for(var i = 0; i < data.length; i++){
   $("#userlist").append("<li><span style='color:red'>id="+data[i].id+"</span>,account="+data[i].account+",name="+data[i].name+",address="+data[i].address+"</li>");
  }
  } catch (e) {};
  
  }
  ,
  error : function(e) {
  alert("sys error");
  }
 });
 
 $("#adduser").on("click", function() {
 var account = $("#account").val();
 var name = $("#name").val();
 var address = $("#address").val();
 $.ajax({
 url : 'adduser.action',
 type : 'post',
 datatype : 'json',
 data : {
  account : account,
  name : name,
  address : address
 },
 success : function(data) {
  try {
  
  $("#userlist").append("<li>account="+account+",name="+name+",address="+address+"</li>");
  alert("添加成功");
  } catch (e) {

  }
 },
 error : function(e) {
  alert("sys error");
 }
 });

 });
 });
</script>
</body>
</html>

六、测试效果：

struts2运行正常；

测试二级缓存是否ok，查询所有user；

第一次查询：cache未命中，访问数据库：

第二次以及接下来的多次查询，cache命中，没有访问数据库：

@author   风一样的码农

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