Struts2以WebWork优秀的设计思想为核心，吸收了 Struts框架的部分优点，提供了一个更加整洁的MVC设计模式实现的Web 应用程序框架。 Struts2引入了几个新的框架特性：从逻辑中分离出横切关注点的拦截器、减少或者消除配置文件、贯穿整个框架的强大表达式语言、支持可变更和可重用的基于MVC模式的标签API， Struts2充分利用了从其它MVC框架学到的经验和教训，使得 Struts2框架更加清晰灵活。
Struts2的详细交教程可以看：http://www.yiibai.com/struts_2/
为什么要用Struts2：
struts2其实就是为我们封装了servlet，简化了jsp跳转的复杂操作，并且提供了易于编写的标签，可以快速开发view层的代码。
过去，我们用jsp和servlet搭配，实现展现时，大体的过程是：
1 jsp触发action
2 servlet接受action,交给后台class处理
3 后台class跳转到其他的jsp，实现数据展现
现在有了struts2，实现过程变为
1 jsp触发action
2 struts2拦截请求，调用后台action
3 action返回结果，由不同的jsp展现数据
Struts2的优势：
Struts2有两方面的技术优势，一是所有的Struts2应用程序都是基于client/server HTTP交换协议，The Java Servlet API揭示了Java Servlet只是Java API的一个很小子集，这样我们可以在业务逻辑部分使用功能强大的Java语言进行程序设计。
二是提供了对MVC的一个清晰的实现，这一实现包含了很多参与对所以请求进行处理的关键组件，如：拦截器、OGNL表达式语言、堆栈。
因为struts2有这样目标，并且有这样的优势，所以，这是我们学习struts2的理由，下面，我们在深入剖析一下struts的工作原理。
Struts2工作原理：
Struts2简单实例：
web.xml
<?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>1101Strtus2</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>/*</url-pattern>
</filter-mapping>
</web-app>
struts2配置文件:
<?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>
<!-- 开启方法时调用 -->
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<!-- 打开开发模式 -->
<constant name="struts.devMode" value="true" />
<package name="helloworld" namespace="/helloworld" extends="struts-default">
<action name="test" class="com.hanqi.action.HelloWorldAction">
<result>
/page/success.jsp
</result>
</action>
</package>
</struts>
<result>标签可以在同一个action中设置多个，根据他的name属性来区分。
java类：
package com.hanqi.action;
import com.opensymphony.xwork2.ActionSupport;
public class HelloWorldAction extends ActionSupport{
@Override
public String execute(){
System.out.println("执行execute方法！！！");
return "fail";
}
}
主页：
<%@ 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>
</head>
<body>
<a href="helloworld/test">跳转</a>
</body>
</html>
点击链接，就会跳到根据相应的方法找到相应的页面。
Struts2传参数：
package com.hanqi.action;
import java.util.Date;
import com.alibaba.fastjson.JSONObject;
import com.hanqi.model.AppUser;
public class TestAction2 extends BaseAction {
private static final long serialVersionUID = 1L;
private Date dateStr;
private AppUser appUser;
private JSONObject jo;
public String test1() {
System.out.println(dateStr);
return SUCCESS;
}
public String test2() {
System.out.println(appUser);
return SUCCESS;
}
public String doJson() {
AppUser user = new AppUser();
user.setId(123);
user.setUsername("admin");
user.setPassword("321");
JSONObject _jo = new JSONObject();
_jo.put("success", true);
_jo.put("result", user);
this.setJo(_jo);
return SUCCESS;
}
public Date getDateStr() {
return dateStr;
}
public void setDateStr(Date dateStr) {
this.dateStr = dateStr;
}
public AppUser getAppUser() {
return appUser;
}
public void setAppUser(AppUser appUser) {
this.appUser = appUser;
}
public JSONObject getJo() {
return jo;
}
public void setJo(JSONObject jo) {
this.jo = jo;
}
}
package com.hanqi.action;
import com.hanqi.model.AppUser;
import com.opensymphony.xwork2.ModelDriven;
public class TestAction extends BaseAction implements ModelDriven<AppUser> {
private static final long serialVersionUID = 1L;
private String username;
private AppUser appUser;
public String testMethod() {
System.out.println(username);
getRequest().setAttribute("param1", username);
return SUCCESS;
}
public String testMethod2() {
System.out.println(appUser);
return SUCCESS;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public AppUser getAppUser() {
return appUser;
}
public void setAppUser(AppUser appUser) {
this.appUser = appUser;
}
@Override
public AppUser getModel() {
if (appUser == null) {
appUser = new AppUser();
}
return appUser;
}
}
package com.hanqi.model;
import java.util.Date;
public class AppUser {
private Integer id;
private String username;
private String password;
private Date birthday;
public AppUser() {
super();
}
public AppUser(Integer id, String username, String password) {
super();
this.id = id;
this.username = username;
this.password = password;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "AppUser [id=" + id + ", username=" + username + ", password=" + password + ", birthday=" + birthday
+ "]";
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
}
package com.hanqi.util;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import org.apache.struts2.util.StrutsTypeConverter;
import com.opensymphony.xwork2.conversion.TypeConversionException;
/*
* 日期转换类
*/
public class MyDateConvertor extends StrutsTypeConverter {
private static final SimpleDateFormat[] sdf = {
new SimpleDateFormat("yyyyMMdd"),
new SimpleDateFormat("yyyy-MM-dd"),
new SimpleDateFormat("yyyy年MM月dd日"),
new SimpleDateFormat("yyyy/MM/dd")
};
@Override
public Object convertFromString(Map arg0, String[] values, Class arg2) {
String dateString = values[0];
Date date = null;
for(int i=0;i<sdf.length;i++) {
try {
date = sdf[i].parse(dateString);
return date;
} catch (ParseException e) {
// e.printStackTrace();
continue;
}
}
throw new TypeConversionException("没有记录的日期类型..");
}
@Override
public String convertToString(Map arg0, Object arg1) {
// TODO Auto-generated method stub
return null;
}
}
log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.opensymphony.xwork2" level="debug"/>
<Logger name="org.apache.struts2" level="debug"/>
<Root level="warn">
<AppenderRef ref="STDOUT"/>
</Root>
</Loggers>
</Configuration>
struts2.xml
<?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>
<!-- 开启动态方法调用 -->
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<!-- 打开开发模式 -->
<constant name="struts.devMode" value="true" />
<package name="helloworld" namespace="/helloworld" extends="json-default">
<action name="helloworld" class="com.hanqi.action.HelloWorldAction">
<result name="success">/page/success.jsp</result>
<result name="fail">/page/fail.jsp</result>
</action>
<action name="test1" class="com.hanqi.action.TestAction" method="testMethod">
<result>/page/result.jsp</result>
</action>
<action name="test2" class="com.hanqi.action.TestAction" method="testMethod2">
<result>/page/result.jsp</result>
</action>
<action name="test3" class="com.hanqi.action.TestAction2" method="test1">
<result>/page/result.jsp</result>
</action>
<action name="test4" class="com.hanqi.action.TestAction2" method="test2">
<result>/page/result.jsp</result>
</action>
<action name="*_*" class="com.hanqi.action.{1}Action">
<result>
/page/{2}.jsp
</result>
</action>
<action name="testjson" class="com.hanqi.action.TestAction2" method="doJson">
<result type="json">
<param name="root">jo</param>
</result>
</action>
</package>
</struts>
xwork日期转换
java.util.Date=com.hanqi.util.MyDateConvertor
index.xml
<%@ 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>
<script type="text/javascript" src="js/jquery-1.12.3.min.js"></script>
<script type="text/javascript">
$(function() {
$("#btn").click(function() {
$.ajax({
url:"helloworld/testjson.action",
type:"post",
dataType:"json",
success:function(data) {
console.log(data);
},
error:function() {
alert("ERROR !");
}
});
});
});
</script>
</head>
<body>
<a href="helloworld/test.action">测试链接</a><br>
<a href="helloworld/test1.action?username=admin">测试链接_传递参数</a><br>
<form action="helloworld/test1.action" method="post">
<input name="username" /><input type="submit" value="提交" />
</form>
<hr>
<form action="helloworld/test2.action" method="post">
<input name="username" /><input name="password" /><input type="submit" value="提交" />
</form>
<hr>
<form action="helloworld/test3.action" method="post">
<input name="dateStr" /><input type="submit" value="提交" />
</form>
<hr>
<h1>不实现ModelDriven接口传递实体类</h1>
<form action="helloworld/test4.action" method="post">
<input name="appUser.id" />
<input name="appUser.username" />
<input name="appUser.password" />
<input name="appUser.birthday" />
<input type="submit" value="提交" />
</form>
<a href="helloworld/Login_success">测试链接2</a><button id="btn">测试json</button>
</body>
</html>