HttpServlet.Response

1.向客户端发送数据

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);
    }

}

View Code

字符串送使用getWrite();

字节传送使用getOutStream()

这两个流不能够同时使用,为什么？

没有手动的关闭流，web服务器会检测帮忙关闭，主动关闭更好

2.SenRedirect可以实现重定向功能

当用户登录成功后显示到登录成功页面MainFrame.java

1.静态变量

自我实现截图：

2.使用SendRedirect,不能传递对象

修改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);
    }

}

View Code

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);
    }

}

View Code

3.使用session传递，可以传递对象

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);
    }

}

View Code

传递对象处理;

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)){
            request.getSession().setAttribute("loginuser", username);
            response.sendRedirect("/user/MainFrame?uname="+username);
            TestServlet user=new TestServlet();
            user.setName(username);
            user.setPassword(password);
            request.getSession().setAttribute("userobj", user);
        }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);
    }

}

View Code

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");
        String username2=(String) request.getSession().getAttribute("loginuser");
        //获取Session中的对象
        TestServlet user=(TestServlet) request.getSession().getAttribute("userobj");
        out.println("<h1>主界面</h1>"+username);
        out.println("<a href='/user/Loin'>返回重新登陆</a>");
        out.println(username2);
        out.println("返回对象的结果"+user.getName()+user.getPassword());
    }

    /**
     * @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

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原文地址：https://www.cnblogs.com/helloworld2019/p/10993253.html