struts2：JSP頁面及Action中獲取HTTP參數（parameter）的幾種方式

時間 2019-11-06

標籤 struts2 struts jsp 頁面 action 獲取 http 參數 parameter 幾種方式欄目 Struts 简体版

原文原文鏈接

本文演示了JSP中獲取HTTP參數的幾種方式，還有action中獲取HTTP參數的幾種方式。html

1. 建立JSP頁面（testParam.jsp）

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page isELIgnored="false"%>
<%@ taglib uri="/struts-tags" prefix="s"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
    </head>
    <body>
        JSP頁面中三種獲取HTTP Parameter的方法：
        <br/>
        1.<s:property value="#parameters.username"/>
        <br/>
        2.<s:property value="#parameters['remark']"/>
        <br/>
        3.<%=request.getParameter("username")%>
        <br/>
        <s:form action="testParam" method="post">
            用戶名：<s:textfield name="username"></s:textfield>
            <br/>
            備註：<s:textfield name="remark"></s:textfield>
            <br/>
            <s:submit value="提交"></s:submit>
            <br/>
        </s:form>
    </body>
</html>

2. 建立Action類（ParameterTestAction.java）

package com.clzhang.struts2.demo4;

import java.util.*;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ActionContext;
import org.apache.struts2.ServletActionContext;
import javax.servlet.http.HttpServletRequest;

public class ParameterTestAction extends ActionSupport {
    public static final long serialVersionUID = 1;

    private String username;
    private String remark;

    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getRemark() {
        return remark;
    }
    public void setRemark(String remark) {
        this.remark = remark;
    }

    public String execute() throws Exception {
        // 方式一：將參數設置爲Action的屬性，OGNL會自動填充它
        System.out.println("1.把參數做爲Action的屬性...");
        System.out.println("username=" + this.username);
        System.out.println("remark=" + this.remark);

        // 方法二：在Action中使用ActionContext獲得包含parameter的Map以獲取參數
        ActionContext context = ActionContext.getContext();
        Map parameterMap = context.getParameters();
        String usernameArray[] = (String[]) parameterMap.get("username");
        String remarkArray[] = (String[]) parameterMap.get("remark");
        System.out.println("2.經過ActionContext.getContext().getParameters()取得...");
        System.out.println("username: " + usernameArray[0]);
        System.out.println("remark: " + remarkArray[0]);

        // 方法三：在Action中取得HttpServletRequest對象，常規方法取得
        HttpServletRequest request = (HttpServletRequest) context
                .get(ServletActionContext.HTTP_REQUEST);
        String username = request.getParameter("username");
        String remark = request.getParameter("remark");
        System.out.println("3.經過HttpServletRequest對象取得...");
        System.out.println("username: " + username);
        System.out.println("remark: " + remark);
        
        return SUCCESS;
    }
}

3. 修改struts.xml文件

        <action name="testParam" class="com.clzhang.struts2.demo4.ParameterTestAction">
            <result name="success">/struts2/demo4/testParam.jsp</result>
        </action>