Jsp--(使用Servlet處理表單提交的請求__實現頁面轉發__獲取當前服務器的路徑)

1.1使用Servlet處理表單提交的請求

創建並通過註解配置名爲MyServlet的Servlet類，此類繼承HttpServlet類並重寫了dopost（）方法，用於處理瀏覽器的請求：

package yuan;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#HttpServlet()
	 */
	public MyServlet() {
		super();
	}

	protected void doPost(HttpServletRequest request, 
              HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		String name=request.getParameter("name");
		PrintWriter writer=response.getWriter();
		if(name!=null) {
			writer.write("hello"+name+"!");
			writer.flush();
			writer.close();
		}
	}

}

說明：從HttpServletResponse對象中獲取的輸出流，在完成業務邏輯處理後應刷新緩衝區的數據後關閉輸出流對象，以及時釋放資源.

創建名爲index.jsp的頁面，作爲程序的主頁面，在其中編寫一個表單，用於向Servlet提交請求。

<%@ 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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="MyServlet" method="post">
<p>請輸入您的姓名：<input type="text" name="name"></p>
<p><input type="submit" value="提交"/></p>
</form>
</body>
</html>

運行結果：

------------------------------------------------------------------------------------

單擊“提交”按鈕後出現的效果

1.2使用servlet實現頁面轉發：

創建名稱爲ForwardServlet.java的類文件，該類繼承了HttpServlet類，在該servlet的doGet()方法中調用RequestDispatcher接口的forward()方法向頁面轉發到main.jsp頁面。下面就是ForwardServlet類的具體代碼（servlet）:

package com.wgh;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
/**
 * Servlet implementation class FordwardServlet
 */
@WebServlet("/FordwardServlet")
public class FordwardServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public FordwardServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, 
			HttpServletResponse response) throws ServletException, IOException {
		RequestDispatcher requestDispatcher=request.getRequestDispatcher("main.jsp");
		requestDispatcher.forward(request,response);
	}

	/**
	 * @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);
	}

}

main.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>主界面</title>
</head>
<body>
歡迎訪問明日科技網站！——main.jsp
</body>
</html>

運行結果；

1.3在Servlet中獲取當前副武器的路徑：

SurePath.java:

package com.wgh;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet實現類SurePath
 */
@WebServlet("/SurePath")
public class SurePath extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public SurePath() {
        super();
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html; charset=UTF-8");
        ServletContext context = this.getServletContext();
        PrintWriter out = response.getWriter();
        out.print("獲取當前服務器的真實路徑：" + context.getRealPath("") + "");
	}
}

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 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">
  <display-name>7.2</display-name>
  <welcome-file-list>
    <welcome-file>SurePath</welcome-file>
  </welcome-file-list>
</web-app>

運行結果：