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
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8"?>
2 <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">
3 <display-name>1101Strtus2</display-name>
4
5 <filter>
6 <filter-name>struts2</filter-name>
7 <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
8 </filter>
9
10 <filter-mapping>
11 <filter-name>struts2</filter-name>
12 <url-pattern>/*</url-pattern>
13 </filter-mapping>
14
15 </web-app>struts2配置文件:
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE struts PUBLIC
3 "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
4 "http://struts.apache.org/dtds/struts-2.3.dtd">
5
6 <struts>
7 <!-- 开启方法时调用 -->
8 <constant name="struts.enable.DynamicMethodInvocation" value="false" />
9 <!-- 打开开发模式 -->
10 <constant name="struts.devMode" value="true" />
11
12 <package name="helloworld" namespace="/helloworld" extends="struts-default">
13 <action name="test" class="com.hanqi.action.HelloWorldAction">
14 <result>
15 /page/success.jsp
16 </result>
17 </action>
18 </package>
19 </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：
代码语言：javascript复制 1 package com.hanqi.action;
2
3 import com.opensymphony.xwork2.ActionSupport;
4
5 public class HelloWorldAction extends ActionSupport{
6
7 @Override
8 public String execute(){
9 System.out.println("执行execute方法！！！");
10 return "fail";
11 }
12 }主页：
代码语言：javascript复制 1 <%@ page language="java" contentType="text/html; charset=utf-8"
2 pageEncoding="utf-8"%>
3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4 <html>
5 <head>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <title>Insert title here</title>
8 </head>
9 <body>
10 <a href="helloworld/test">跳转</a>
11 </body>
12 </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：
1 package com.hanqi.action;
2
3 import java.util.Date;
4
5 import com.alibaba.fastjson.JSONObject;
6 import com.hanqi.model.AppUser;
7
8 public class TestAction2 extends BaseAction {
9
10 private static final long serialVersionUID = 1L;
11
12 private Date dateStr;
13
14 private AppUser appUser;
15
16 private JSONObject jo;
17
18 public String test1() {
19 System.out.println(dateStr);
20
21 return SUCCESS;
22 }
23
24 public String test2() {
25 System.out.println(appUser);
26
27 return SUCCESS;
28 }
29
30 public String doJson() {
31 AppUser user = new AppUser();
32 user.setId(123);
33 user.setUsername("admin");
34 user.setPassword("321");
35
36 JSONObject _jo = new JSONObject();
37 _jo.put("success", true);
38 _jo.put("result", user);
39 this.setJo(_jo);
40
41 return SUCCESS;
42 }
43
44 public Date getDateStr() {
45 return dateStr;
46 }
47
48 public void setDateStr(Date dateStr) {
49 this.dateStr = dateStr;
50 }
51
52 public AppUser getAppUser() {
53 return appUser;
54 }
55
56 public void setAppUser(AppUser appUser) {
57 this.appUser = appUser;
58 }
59
60 public JSONObject getJo() {
61 return jo;
62 }
63
64 public void setJo(JSONObject jo) {
65 this.jo = jo;
66 }
67
68
69 } 1 package com.hanqi.action;
2
3 import com.hanqi.model.AppUser;
4 import com.opensymphony.xwork2.ModelDriven;
5
6 public class TestAction extends BaseAction implements ModelDriven<AppUser> {
7
8 private static final long serialVersionUID = 1L;
9
10 private String username;
11
12 private AppUser appUser;
13
14 public String testMethod() {
15 System.out.println(username);
16 getRequest().setAttribute("param1", username);
17
18 return SUCCESS;
19 }
20
21 public String testMethod2() {
22 System.out.println(appUser);
23 return SUCCESS;
24 }
25
26 public String getUsername() {
27 return username;
28 }
29
30 public void setUsername(String username) {
31 this.username = username;
32 }
33
34 public AppUser getAppUser() {
35 return appUser;
36 }
37
38 public void setAppUser(AppUser appUser) {
39 this.appUser = appUser;
40 }
41
42 @Override
43 public AppUser getModel() {
44 if (appUser == null) {
45 appUser = new AppUser();
46 }
47 return appUser;
48 }
49 } 1 package com.hanqi.model;
2
3 import java.util.Date;
4
5 public class AppUser {
6
7 private Integer id;
8 private String username;
9 private String password;
10 private Date birthday;
11
12 public AppUser() {
13 super();
14 }
15
16 public AppUser(Integer id, String username, String password) {
17 super();
18 this.id = id;
19 this.username = username;
20 this.password = password;
21 }
22
23 public Integer getId() {
24 return id;
25 }
26
27 public void setId(Integer id) {
28 this.id = id;
29 }
30
31 public String getUsername() {
32 return username;
33 }
34
35 public void setUsername(String username) {
36 this.username = username;
37 }
38
39 public String getPassword() {
40 return password;
41 }
42
43 public void setPassword(String password) {
44 this.password = password;
45 }
46
47 @Override
48 public String toString() {
49 return "AppUser [id=" id ", username=" username ", password=" password ", birthday=" birthday
50 "]";
51 }
52
53 public Date getBirthday() {
54 return birthday;
55 }
56
57 public void setBirthday(Date birthday) {
58 this.birthday = birthday;
59 }
60
61 } 1 package com.hanqi.util;
2
3 import java.text.ParseException;
4 import java.text.SimpleDateFormat;
5 import java.util.Date;
6 import java.util.Map;
7
8 import org.apache.struts2.util.StrutsTypeConverter;
9
10 import com.opensymphony.xwork2.conversion.TypeConversionException;
11 /*
12 * 日期转换类
13 */
14 public class MyDateConvertor extends StrutsTypeConverter {
15
16 private static final SimpleDateFormat[] sdf = {
17 new SimpleDateFormat("yyyyMMdd"),
18 new SimpleDateFormat("yyyy-MM-dd"),
19 new SimpleDateFormat("yyyy年MM月dd日"),
20 new SimpleDateFormat("yyyy/MM/dd")
21 };
22
23 @Override
24 public Object convertFromString(Map arg0, String[] values, Class arg2) {
25
26 String dateString = values[0];
27 Date date = null;
28 for(int i=0;i<sdf.length;i ) {
29 try {
30 date = sdf[i].parse(dateString);
31 return date;
32 } catch (ParseException e) {
33 // e.printStackTrace();
34 continue;
35 }
36 }
37 throw new TypeConversionException("没有记录的日期类型..");
38 }
39
40 @Override
41 public String convertToString(Map arg0, Object arg1) {
42 // TODO Auto-generated method stub
43 return null;
44 }
45
46 }log4j2.xml
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8"?>
2 <Configuration>
3 <Appenders>
4 <Console name="STDOUT" target="SYSTEM_OUT">
5 <PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
6 </Console>
7 </Appenders>
8 <Loggers>
9 <Logger name="com.opensymphony.xwork2" level="debug"/>
10 <Logger name="org.apache.struts2" level="debug"/>
11 <Root level="warn">
12 <AppenderRef ref="STDOUT"/>
13 </Root>
14 </Loggers>
15 </Configuration>struts2.xml
代码语言：javascript复制 1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE struts PUBLIC
3 "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
4 "http://struts.apache.org/dtds/struts-2.3.dtd">
5
6 <struts>
7 <!-- 开启动态方法调用 -->
8 <constant name="struts.enable.DynamicMethodInvocation" value="false" />
9 <!-- 打开开发模式 -->
10 <constant name="struts.devMode" value="true" />
11
12 <package name="helloworld" namespace="/helloworld" extends="json-default">
13 <action name="helloworld" class="com.hanqi.action.HelloWorldAction">
14 <result name="success">/page/success.jsp</result>
15 <result name="fail">/page/fail.jsp</result>
16 </action>
17
18 <action name="test1" class="com.hanqi.action.TestAction" method="testMethod">
19 <result>/page/result.jsp</result>
20 </action>
21
22 <action name="test2" class="com.hanqi.action.TestAction" method="testMethod2">
23 <result>/page/result.jsp</result>
24 </action>
25
26 <action name="test3" class="com.hanqi.action.TestAction2" method="test1">
27 <result>/page/result.jsp</result>
28 </action>
29
30 <action name="test4" class="com.hanqi.action.TestAction2" method="test2">
31 <result>/page/result.jsp</result>
32 </action>
33
34 <action name="*_*" class="com.hanqi.action.{1}Action">
35 <result>
36 /page/{2}.jsp
37 </result>
38 </action>
39
40 <action name="testjson" class="com.hanqi.action.TestAction2" method="doJson">
41 <result type="json">
42 <param name="root">jo</param>
43 </result>
44 </action>
45
46 </package>
47
48 </struts>xwork日期转换
代码语言：javascript复制1 java.util.Date=com.hanqi.util.MyDateConvertorindex.xml
代码语言：javascript复制 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
2 pageEncoding="UTF-8"%>
3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
4 <html>
5 <head>
6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
7 <title>Insert title here</title>
8 <script type="text/javascript" src="js/jquery-1.12.3.min.js"></script>
9 <script type="text/javascript">
10 $(function() {
11 $("#btn").click(function() {
12 $.ajax({
13 url:"helloworld/testjson.action",
14 type:"post",
15 dataType:"json",
16 success:function(data) {
17 console.log(data);
18 },
19 error:function() {
20 alert("ERROR !");
21 }
22 });
23 });
24 });
25 </script>
26 </head>
27 <body>
28 <a href="helloworld/test.action">测试链接</a><br>
29 <a href="helloworld/test1.action?username=admin">测试链接_传递参数</a><br>
30 <form action="helloworld/test1.action" method="post">
31 <input name="username" /><input type="submit" value="提交" />
32 </form>
33 <hr>
34 <form action="helloworld/test2.action" method="post">
35 <input name="username" /><input name="password" /><input type="submit" value="提交" />
36 </form>
37 <hr>
38 <form action="helloworld/test3.action" method="post">
39 <input name="dateStr" /><input type="submit" value="提交" />
40 </form>
41 <hr>
42 <h1>不实现ModelDriven接口传递实体类</h1>
43 <form action="helloworld/test4.action" method="post">
44 <input name="appUser.id" />
45 <input name="appUser.username" />
46 <input name="appUser.password" />
47 <input name="appUser.birthday" />
48 <input type="submit" value="提交" />
49 </form>
50 <a href="helloworld/Login_success">测试链接2</a><button id="btn">测试json</button>
51 </body>
52 </html>
