struts原理
配置文件：strust.xml
<?xml version="1.0" encoding="UTF-8"?>
<strust>
//name:访问这个资源使用的url
//class:资源的位置
//method:资源中的方法名
<action name="login" class="com.javawu.action.LoginAction" method="login">
//结果集
//name:方法的返回值
//对应的资源名
<result name="success">/index.jsp</result>
<result name="error">/error.jsp</result>
</action>
</strust>
实体类：ActionMapping.java
package com.javawu.action;
import java.util.Map;
public class ActionMapping {
private String name;
private String cls;
private String method;
private Map<String, String> result;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCls() {
return cls;
}
public void setCls(String cls) {
this.cls = cls;
}
public String getMethod() {
return method;
}
public void setMethod(String method) {
this.method = method;
}
public Map<String, String> getResult() {
return result;
}
public void setResult(Map<String, String> result) {
this.result = result;
}
}
解析xml类：ActionManager.java
package com.javawu.action;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
//解析xml文件
public class ActionManager {
private List<ActionMapping> list = null;
public List<ActionMapping> getList() {
return list;
}
public ActionManager() {
list = new ArrayList<>();
try {
parseXML();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private void parseXML() throws Exception {
SAXReader saxReader = new SAXReader();
InputStream inputStream = ActionManager.class.getResourceAsStream("/struts.xml");
Document document = saxReader.read(inputStream);
Element rootElement = document.getRootElement();
List<Element> aEles = rootElement.elements("action");
if(aEles != null) {
for (Element element : aEles) {
ActionMapping actionMapping = new ActionMapping();
actionMapping.setName(element.attributeValue("name"));
actionMapping.setCls(element.attributeValue("class"));
actionMapping.setMethod(element.attributeValue("method"));
List<Element> rEles = element.elements("result");
if(rEles != null) {
Map<String, String> map = new HashMap<>();
for(Element res : rEles) {
map.put(res.attributeValue("name"), res.getText());
}
actionMapping.setResult(map);
}
list.add(actionMapping);
}
}
}
}
页面资源：login.jsp
<%@ 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>
//访问资源时使用在配置文件中配置的url
<form action="/X01_Struts/login.action" method="post">
user<input type="text" name="user_name" /><br/>
password<input type="password" name="user_password" /><br/>
<input type="submit" value="登录">
</form>
</body>
</html>
在web.xml中增加配置
<servlet>
<description></description>
<display-name>ActionServlet</display-name>
<servlet-name>ActionServlet</servlet-name>
<servlet-class>com.javawu.action.ActionServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ActionServlet</servlet-name>
//访问所有以.action为结尾的资源时都会被ActionServlet.java拦截
<url-pattern>*.action</url-pattern>
</servlet-mapping>
ActionServlet.java
package com.javawu.action;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.swing.internal.plaf.metal.resources.metal;
/**
* Servlet implementation class ActionServlet
*/
public class ActionServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public ActionServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
ActionManager actionManager = new ActionManager();
List<ActionMapping> list = actionManager.getList();
//获取请求的uri
String uri = request.getRequestURI();
//根据uri获取请求的资源
uri = uri.substring(uri.lastIndexOf("/") + 1, uri.lastIndexOf(".action"));
for(ActionMapping actionMapping : list) {
if(actionMapping.getName().equals(uri)) {
try {
Class cls = Class.forName(actionMapping.getCls());
Object newInstance = cls.newInstance();
Method method = cls.getDeclaredMethod(actionMapping.getMethod(), HttpServletRequest.class, HttpServletResponse.class);
String ret = (String)method.invoke(newInstance, request, response);
for(String result : actionMapping.getResult().keySet()) {
if (result.equals(ret)) {
response.sendRedirect(request.getContextPath() + actionMapping.getResult().get(result));
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
LoginAction.java
package com.javawu.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginAction {
public String login(HttpServletRequest request, HttpServletResponse response) {
if(request.getParameter("user_name").equals("admin") && request.getParameter("user_password").equals("123")) {
return "success";
}else {
return "error";
}
}
}
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