Struts1入門實例（簡單登陸）

如今開始加入公司的核心項目，但因爲項目開發比較早，因此使用的技術不是很新潮，前臺用的仍是struts1。

雖然不是什麼新技術，但仍能夠從中學到好多東西的。花了一個晚上的時間終於把struts1的流程跑通了。

省略了建立過程及加入jar包的過程，直接進入正題。

首頁要在web.xml中添加相應的struts配置：

<servlet>
        <servlet-name>action</servlet-name>
        <servlet-class>
            org.apache.struts.action.ActionServlet
        </servlet-class>
        <init-param>
            <param-name>config</param-name>
            <param-value>/WEB-INF/struts-config.xml</param-value>
        </init-param>
        <init-param>
            <param-name>debug</param-name>
            <param-value>2</param-value>
        </init-param>
        <init-param>
            <param-name>detail</param-name>
            <param-value>2</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>action</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

而後在config所對應的目錄下添加struts配置文件struts-config.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts-config PUBLIC
          "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
          "http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">

<struts-config>

<!-- ActionForm  -->
    <form-beans>
    <!-- name:名稱 type:類路徑 -->
        <form-bean name="loginForm" type="com.login.LoginForm">
        </form-bean>
    </form-beans>
<!-- 設置全局URL，必須寫在Action前面，這樣任何Action均可以使用 -->
    <global-forwards>
        <forward name="result" path="/result.jsp" />
    </global-forwards>

<!-- 註冊Action -->
    <action-mappings>
    <!-- name：名稱 type：類路徑 path：客戶端（JSP）提交到服務器端時指定的路徑（Form表單中的action=」/login.do" -->
        <action path="/login" type="com.login.LoginAction"
            name="loginForm" scope="request">
            <!-- 局部URL，只有這個action能夠使用 -->
            <forward name="success" path="/success.jsp"></forward>
            <forward name="error" path="/error.jsp"></forward>
        </action>
    </action-mappings>


</struts-config>

注：Action和Form的關係是一個Action只能對應一個Form（經過Action的name屬性）

而一個Form能夠被多個Action調用

LoginAction.java

package com.login;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class LoginAction extends Action {

    @Override
    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws Exception {
        LoginForm lf = (LoginForm) form;
        String username = lf.getUsername();
        String password = lf.getPassword();
        String errorInfo = "";
        String result = UserManager.getInstance().login(username, password);
        if (result.equals("success")) {
            request.setAttribute("username", username);
            return mapping.findForward("success");
        } else if (result.equals("username")) {
            errorInfo = "密碼錯誤";
        } else {
            errorInfo = "用戶名錯誤";
        }
        request.setAttribute("errorInfo", errorInfo);
        return mapping.findForward("error");
    }

}

LoginForm.java

package com.login;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;

public class LoginForm extends ActionForm {

    private String username;
    private String password;

    public void reset(ActionMapping mapping, HttpServletRequest request) {
        System.out.println("--------reset()-------------");
        super.reset(mapping, request);
    }

    public ActionErrors validate(ActionMapping mapping,
            HttpServletRequest request) {
        System.out.println("--------validate()-------------");
        return super.validate(mapping, request);
    }

    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;
    }

}

對我我的來講最重要的是前臺jsp頁面沒有掌握，常常在頁面上花費不少時間

在編寫JSP頁面時要用struts標籤，而我常常會忘記

引入jsp標籤

<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>首頁</title>
	</head>

	<body>
		<html:form action="/login.do">
			用戶名：<html:text property="username"></html:text><br/>
			密碼: <html:password property="password"></html:password><br/>
			<html:submit>submit</html:submit>
		</html:form>
	</body>
</html>

 

展現結果（將Action的返回值展現到JSP頁面上）

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>Error</title>
	</head>
	<body>
		<bean:write name="errorInfo" scope="request" />
	</body>
</html>