HttpServlet.Response

1. Send data to the client

getWrite ();

getOutputStream();

package com.test;

import java.io.IOException;
import java.io.OutputStream;

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 org.apache.catalina.connector.OutputBuffer;

/**
 * Servlet implementation class TestServlet
 */
@WebServlet("/TestServlet")
public class TestServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public TestServlet() {
        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
        response.setCharacterEncoding("utf-8");
        OutputStream os=response.getOutputStream();
        //转换成二进制的数据
        os.write("hello,world".getBytes());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    this.doGet(request,response);
    }

}

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String sent using getWrite ();

Byte is transferred using getOutStream ()

 These two streams can not be used simultaneously, and why?

No manual shut down stream, web server detects help shut down, take the initiative to close better

2.SenRedirect can achieve redirection

When displayed after a user successful login to the login success page MainFrame.java

1. static variables

Screenshot self-realization:

2. SendRedirect, objects can not pass

 Modify ControlServlet.java

package com.controller;

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

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.xml.ws.Response;

import com.test.TestServlet;

/**
 * Servlet implementation class ControlServlet
 */
@WebServlet("/ControlServlet")
public class ControlServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ControlServlet() {
        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
        PrintWriter out=response.getWriter();
        response.setContentType("text/html;charset=utf-8");
        String username=request.getParameter("username");
        String password=request.getParameter("password");
//        System.out.println(username+password);
        //这里进行简单的认证
        TestServlet.name=username;
        if("wangzhi".equals(username)&&"123456".equals(password)){
            response.sendRedirect("/user/MainFrame?uname="+username);
        }else{
            response.sendRedirect("/user/Loin");
        }
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request,response);
    }

}

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MainFrame.java

package com.view;

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

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 com.test.TestServlet;

/**
 * Servlet implementation class MainFrame
 */
@WebServlet("/MainFrame")
public class MainFrame extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainFrame() {
        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
        response.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        String username=request.getParameter("uname");
        out.println("<h1>主界面</h1>"+username);
        out.println("<a href='/user/Loin'>返回重新登陆</a>");
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

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3. Using the session transfer, the object can pass

package com.view;

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

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 com.test.TestServlet;

/**
 * Servlet implementation class MainFrame
 */
@WebServlet("/MainFrame")
public class MainFrame extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainFrame() {
        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
        response.setCharacterEncoding("utf-8");
        PrintWriter out = response.getWriter();
        String username=request.getParameter("uname");
        String username2=(String) request.getSession().getAttribute("loginuser");
        out.println("<h1>主界面</h1>"+username);
        out.println("<a href='/user/Loin'>返回重新登陆</a>");
        out.println(username2);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request, response);
    }

}

View Code

package com.controller;

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

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.xml.ws.Response;

import com.test.TestServlet;

/**
 * Servlet implementation class ControlServlet
 */
@WebServlet("/ControlServlet")
public class ControlServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ControlServlet() {
        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
        PrintWriter out=response.getWriter();
        response.setContentType("text/html;charset=utf-8");
        String username=request.getParameter("username");
        String password=request.getParameter("password");
//        System.out.println(username+password);
        //这里进行简单的认证
        TestServlet.name=username;
        if("wangzhi".equals(username)&&"123456".equals(password)){
            request.getSession().setAttribute("loginuser", username);
            response.sendRedirect("/user/MainFrame?uname="+username);
        }else{
            response.sendRedirect("/user/Loin");
        }
        
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doGet(request,response);
    }

}

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