Struts2学习第七课 result

result 是action节点的子节点

result 代表action方法执行后，可能去的一个目的地

一个action节点可以配置多个result子节点。

result的name属性值对应着action方法可能有的一个返回值。

result有两个属性，还有一个是type它表示结果的响应类型

result的type属性值在struts-default包的result-types节点的name属性中定义，

常用的有：

dispatcher(默认值):转发，同Servlet中的转发。

redirect:重定向

redirectAction重定向到一个Action，

注意：通过redirect的响应类型也可以便捷的实现redirectAction

chain：转发到一个Action

注意：不能通过redirect的响应类型也可以便捷的实现转发到一个Action

看代码：

struts.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>
    <!-- 配置Struts2可以受理的请求的扩展名 -->
    <constant name="struts.action.extension" value="action,do"></constant>
    <package name="default" namespace="/" extends="struts-default">
        <action name="login-ui">
            <result>/login.jsp</result>
        </action>
        
        <action name="user-login" class="logan.struts.study.UserAction">
            <result name="login-success">/login-success.jsp</result>
        </action>
        
        <action name="logout" class="logan.struts.study.UserAction"
        method="logout">
            <result name="logout-success">/login.jsp</result>
        </action>
        
        <action name="testResult" class="logan.struts.study.TestResultAction"
        >
            <result name="success">/success.jsp</result>
            <!-- 重定向到一个Action -->
            <result name="index" type="redirectAction">
                <param name="actionName">testAction</param>
                <param name="namespace">/logan</param>
            </result>
            
            <!-- 通过redirect的响应类型也可以便捷的实现redirectAction 
            <result name="index" type="redirect">/logan/testAction.do</result>
             -->
            <result name="login" type="redirect">/login.jsp</result>
            <result name="test" type="chain">
                <param name="actionName">testAction</param>
                <param name="namespace">/logan</param>
            
            </result>
        </action>
    
    </package>
    <package name="testPackage" namespace="/logan" extends="struts-default">
        <action name="testAction" class="logan.struts.study.TestAction">
            <result>/success.jsp</result>
        </action>
    </package>
    
</struts>

package logan.struts.study;

public class TestResultAction {
    private int number;
    
    public void setNumber(int number) {
        this.number = number;
    }
    
    public String execute(){
        
        String result = null;
        
        if(number%4 == 0){
            result = "success";
        }else if(number%4 == 1){
            result = "login";
        }else if(number%4 == 2){
            System.out.println("2");
            result = "index";
        }else if(number%4 == 3){
            result = "test";
        }
        
        return result;
    }

}

package logan.struts.study;

public class TestAction {
    
    public String execute(){
        System.out.println("TestAction's execute...");
        return "success";
    }

}

package logan.struts.study;

import java.util.Map;

import org.apache.struts2.dispatcher.SessionMap;
import org.apache.struts2.interceptor.ApplicationAware;
import org.apache.struts2.interceptor.SessionAware;

public class UserAction implements SessionAware,ApplicationAware{
    
    private Map<String, Object> session = null;
    private Map<String, Object> application = null;
    
    private String username;
    
    public void setUsername(String username) {
        this.username = username;
    }
    
    public String logout(){
        //数量减一
        Integer count = (Integer) application.get("count");
        if(count != null && count >0){
            count--;
            application.put("count", count);
        }
        count--;
        
        //session失效
        ((SessionMap)session).invalidate();
        
        return "logout-success";
    }
    
    public String execute(){
        
        //把用户信息存入Session域中
        
        //1.获取session，通过实现RequestAware接口
        
        //获取登录信息
        session.put("username", username);
        //把用户信息存入Session域中
        
        //
        Integer count = (Integer) application.get("count");
        if(count == null){
            count = 0;
        }
        //2.使当前在线人数 + 1
        count++;
        application.put("count", count);
        
        
        return "login-success";
    }

    @Override
    public void setSession(Map<String, Object> session) {
        // TODO Auto-generated method stub
        this.session = session;
        
    }

    @Override
    public void setApplication(Map<String, Object> application) {
        // TODO Auto-generated method stub
        this.application = application;
        
    }

}

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <a href="login-ui.do">LoginUI</a>
    <br><br>
    <a href="testResult.do?number=4">Test ActionSupport</a>
</body>
</html>

login-success.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    Welcome:${sessionScope.username }
    <br><br>
    Count on:${applicationScope.count }
    <br><br>
    <a href="logout.do">Logout</a>
</body>
</html>

login.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <form action="user-login.do" method="post">
        username:<input type="text" name="username">
        <input type="submit" value="Login">
    </form>
</body>
</html>

success.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <h4>Success Page</h4>
</body>
</html>