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