开发者社区> loveincode> 正文
阿里云
为了无法计算的价值
打开APP
阿里云APP内打开

JavaWeb 后端 <三> 之 Response Request 学习笔记

简介:
+关注继续查看

一、响应对象 Response(重点:HTTP协议响应部分)

 

查看 HttpServletResponse

set是 有这个头 修改 没有添加一个新的 和 add 有点小区别

案例:


1. 字节流向客户端输出中文数据 ServletOutputStream


//字节流向客户端输出中文数据
public class ResponseDemo1 extends HttpServlet {
     
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        test2(response);
    }
 
    //解决方案一:更改浏览器的码表(不建议)
        //解决方案二(不建议):向客户端输出一个<meta>标签,模拟了响应消息头:<meta http-equiv='Content-Type' content='text/html;charset=UTF-8'>
            //out.write("<meta http-equiv='Content-Type' content='text/html;charset=UTF-8'>".getBytes());
        //解决方案三(建议):向客户端输出响应消息头:response.setHeader("Content-Type", "text/html;charset=UTF-8");
        //解决方案四(建议):向客户端输出响应消息头response.setContentType("text/html;charset=UTF-8");
         
     
    //字节流输出数据查UTF-8
        private void test2(HttpServletResponse response) throws IOException {
            String data = "不见了远处的青山";
            response.setContentType("text/html;charset=UTF-8");
            ServletOutputStream out = response.getOutputStream();
            out.write(data.getBytes("UTF-8"));//默认情况下:浏览器是乱码的(他默认查GBK)
        }
     
    //字节流输出数据查本地码表
    private void test1(HttpServletResponse response) throws IOException {
        String data = "不见了远处的青山";
        ServletOutputStream out = response.getOutputStream();
        out.write(data.getBytes());//String:  getBytes()查本地默认的码表GBK getBytes(String charset)查指定码表
    }

2. 字符流输出中文数据 PrintWriter


//字符流输出中文数据
public class ResponseDemo2 extends HttpServlet {
     
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String data = "幸福是什么呢";
        //改变字符流查的码表,还能告知客户端用UTF-8进行解码
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        //HttpServletResponse的实例由Tomcat服务器提供,默认查ISO-8859-1的。
        //Tomcat8.X ,默认编码就变为了UTF-8
         
        out.write(data);
    }
     
    private void test1(HttpServletResponse response) throws IOException {
        String data = "幸福是什么";
        //改变字符流查的码表
        response.setCharacterEncoding("UTF-8");
        //告知客户端用UTF-8进行解码
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();//HttpServletResponse的实例由Tomcat服务器提供,默认查ISO-8859-1的。
                                                //Tomcat8.X ,默认编码就变为了UTF-8
        out.write(data);
    }

 3.输出随机验证码图片:CAPTCHA图像


//输出随机验证码图片:CAPTCHA图像
public class ResponseDemo3 extends HttpServlet {
     
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int width = 120;
        int height = 25;
        //创建一副内存图像
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        //得到画笔
        Graphics g = image.getGraphics();
            //开始画
            //边线
            g.setColor(Color.BLUE);
            g.drawRect(0, 0, width, height);
            //填充背景色
            g.setColor(Color.YELLOW);
            g.fillRect(1, 1, width-2, height-2);
            //话干扰线
            g.setColor(Color.GRAY);
             
            Random r = new Random();
            for(int i=0;i<9;i++)
                g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
            //验证码
            g.setColor(Color.RED);
            g.setFont(new Font("宋体", Font.ITALIC|Font.BOLD, 19));
//          String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
            int x = 20;
            for(int i=0;i<4;i++){
                g.drawString(r.nextInt(10)+"", x,20 );
//              g.drawString(base.charAt(r.nextInt(base.length()))+"", x, 20);
                x+=18;
            }
        //输出
        response.setHeader("Expires", "-1");
        response.setHeader("Cache-Control", "no-cache");
        response.setHeader("Pragma", "no-cache");
        ImageIO.write(image, "jpg", response.getOutputStream());
    }
 
     
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
 
}

 html


<body>
    <form action="" method="post">
        用户名:<input type="text" name="username"/><br/>
        密码:<input type="password" name="password"/><br/>
        <input type="text" size="3" name="code"/><img id="img1" src="/day08_00_response/servlet/ResponseDemo3"/><a href="javascript:change()">看不清</a><br/>
        <input type="submit" value="登录"/>
    </form>
    <script type="text/javascript">
        function change(){
            var imgObj = document.getElementById("img1");
            imgObj.src="/day08_00_response/servlet/ResponseDemo3?time="+new Date().getTime();//浏览器发现地址没有变化,根本不发请求
        }
    </script>
  </body>

 4.定时刷新  登陆跳转等待


//控制客户端定时刷新
public class ResponseDemo4 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        test2(response);
    }
    //定时刷新到别处
    private void test2(HttpServletResponse response) throws IOException {
        response.setContentType("text/htm;charset=UTF-8");
        response.setHeader("Refresh", "2;URL=http://www.huyifan.cn");
        response.getWriter().write("登录成功,2秒后跳转到主页");
    }
    //定时刷新自己
    private void test1(HttpServletResponse response) throws IOException {
        Random r = new Random();
//      response.setHeader("Refresh", "1");
        response.setIntHeader("Refresh", 1);
        response.getWriter().write(r.nextInt()+"");
    }

 5.控制缓存时间


//控制缓存的时间
//静态资源需要控制缓存时间
//动态资源一般不要缓存
public class ResponseDemo5 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String data = "不见了远处的青山";
        //让他缓存1个小时
        response.setDateHeader("Expires", System.currentTimeMillis()+1*60*60*1000);
        response.setContentType("text/html;charset=UTF-8");
        response.getWriter().write(data);
    }

6.请求重定向


//演示请求重定向:可以重定向到任何地址上
    //发出2次请求
    //地址栏会发生变化
public class ResponseDemo6 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.sendRedirect("http://www.huyifan.com");
    }
    //重定向到应用内的资源
    private void test1(HttpServletResponse response) throws IOException {
        //      response.setStatus(302);
//      response.setHeader("Location", "/day08_00_response/servlet/ResponseDemo7");
        response.sendRedirect("/day08_00_response/servlet/ResponseDemo7");
    }


public class ResponseDemo7 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.getWriter().write("I am yif");
//      response.getOutputStream().write("a".getBytes());
    }

细节:

1、字节流和字符流互斥,只能用其中一个。

2、response的流用完之后自动关(服务器关)

 

二、请求对象 Request(重点:HTTP协议请求部分)

1、HttpServletRequest对象的生命周期

诞生:请求来了

死亡:响应结束

2、也是一个域(范围)对象:请求范围

 

request

Map

setAttribute

getAttribute

removeAttribute‘

 

3、开发中尽量用绝对路径

绝对路径:要不要加应用名称

地址给服务器用的:/就代表当前应用

地址给客户端用的:/day08

 

1. HttpServletRequest中的常用方法


public class RequestDemo1 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String method = request.getMethod();//请求方式
        String uri = request.getRequestURI();//    /day08_01_request/servlet/RequestDemo1
        String url = request.getRequestURL().toString();//  http://localhost:8080/day08_01_request/servlet/RequestDemo1
        String protocal = request.getProtocol();//客户端使用的协议
         
        String remoteIp = request.getRemoteAddr();//来访者的ip
        int port = request.getRemotePort();// 随机的
        String queryString = request.getQueryString();//GET方式:/day08_01_request/servlet/RequestDemo1?username=abc&password=123
                                                //username=abc&password=123
        System.out.println(method);
        System.out.println(uri);
        System.out.println(url);
        System.out.println(protocal);
        System.out.println(remoteIp);
        System.out.println(port);
        System.out.println(queryString);
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}

2. 获取请求消息头


public class RequestDemo2 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        test3(request);
    }
    //得到所有的消息头
    private void test3(HttpServletRequest request) {
        Enumeration<String> e = request.getHeaderNames();
        while(e.hasMoreElements()){
            String headerName = e.nextElement();//透明称
            Enumeration<String> headerValues = request.getHeaders(headerName);
            while(headerValues.hasMoreElements()){
                System.out.println(headerName+":"+headerValues.nextElement());
            }
        }
         
    }
    //http协议是允许头有重复的情况,多个重名的头
    private void test2(HttpServletRequest request) {
        Enumeration<String> e = request.getHeaders("Accept-Encoding");//得到的头值
        while(e.hasMoreElements()){
            String headerValue = e.nextElement();
            System.out.println(headerValue);
        }
         
    }
    //得到指定请求消息头的值。如果没有该头,返回null
    private void test1(HttpServletRequest request) {
        String supportEncoding = request.getHeader("Accept-Encoding");
        if(supportEncoding.contains("gzip")){
            System.out.println("支持gzip压缩");
        }else{
            System.out.println("不支持gzip压缩");
        }
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}

 3.//获取请求参数


public class RequestDemo3 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        test8(request, response);
    }
    //终极解决方案:借助BeanUtil框架      jar包直接放在 web-inf 的 ;lib 文件夹里就ok
    private void test8(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        User user = new User();
        System.out.println("封装前:"+user);
        try {
            BeanUtils.populate(user, request.getParameterMap());
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("封装后:"+user);
    }
    //getParameterMap获取参数:封装到JavaBean中
    private void test7(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //key:请求参数名 value:请求参数值数组
        Map<String,String[]> map = request.getParameterMap();
        User user = new User();
        System.out.println("封装前:"+user);
        for(Map.Entry<String, String[]> me:map.entrySet()){
            String paramName = me.getKey();//参数名称
            String paramValues[] = me.getValue();//参数值
            try {
                PropertyDescriptor pd = new PropertyDescriptor(paramName, User.class);
                Method m = pd.getWriteMethod();//setter方法
                if(paramValues.length>1){
                    m.invoke(user, (Object)paramValues);//参考补充视频:反射main方法
                }else{
                    m.invoke(user, paramValues);
                }
            } catch (Exception e1) {
                e1.printStackTrace();
            }
        }
        System.out.println("封装后:"+user);
    }
    //getParameterMap获取参数
    private void test6(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //key:请求参数名 value:请求参数值数组
        Map<String,String[]> map = request.getParameterMap();
        for(Map.Entry<String, String[]> me:map.entrySet()){
            System.out.println(me.getKey()+"="+Arrays.asList(me.getValue()));
        }
    }
     
    //把请求参数的值封装到JavaBean中
    //约定优于编码:表单的输入域的name取值和JavaBean中的属性(getter和setter方法)保持一致
    private void test5(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
         
         
        Enumeration<String> e = request.getParameterNames();//参数名
        User user = new User();
        System.out.println("封装前:"+user);
        while(e.hasMoreElements()){
            String paramName = e.nextElement();//即是JavaBean中的属性名称
            String paramValue = request.getParameter(paramName);
//          setUsername(paramValue); setPassword(paramValue);
            //JavaBean的内省
            try {
                PropertyDescriptor pd = new PropertyDescriptor(paramName, User.class);
                Method m = pd.getWriteMethod();//setter方法
                m.invoke(user, paramValue);
            } catch (Exception e1) {
                e1.printStackTrace();
            }
        }
        System.out.println("封装后:"+user);
    }  
//  private void test4(HttpServletRequest request, HttpServletResponse response)
//          throws ServletException, IOException {
//      User user = new User();
//      System.out.println("封装前:"+user);
//      String username = request.getParameter("username");
//      String password = request.getParameter("password");
//      String gender = request.getParameter("gender");
//      user.setUsername(username);
//      user.setPassword(password);
//      user.setGender(gender);
//      System.out.println("封装后:"+user);
//  }  
    //以下内容只用简单的程序开发
     
    //获取所有的请求参数名和值
    private void test3(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        Enumeration<String> e = request.getParameterNames();//参数名
        while(e.hasMoreElements()){
            String paramName = e.nextElement();
            String values [] = request.getParameterValues(paramName);
            System.out.println(paramName+"="+Arrays.asList(values));
        }
    }
    //获取重名请求参数的值
    private void test2(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String username = request.getParameter("username");//不区分get还是post的
        String passwords[] = request.getParameterValues("password");//获取重名的请求参数值
        System.out.println(username+":"+Arrays.asList(passwords));
    }
    //获取单一的请求参数的值(用户所有的输入都是String)
    private void test1(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String username = request.getParameter("username");//不区分get还是post的
        String password = request.getParameter("password");
        System.out.println(username+":"+password);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}

domain


public class User {
    private String username;
    private String password[];
    private String gender;
    public String getUsername() {//读属性,属性名称username
        return username;
    }
    public void setUsername(String username) {//写属性,属性名username
        this.username = username;
    }
     
    public String[] getPassword() {
        return password;
    }
    public void setPassword(String[] password) {
        this.password = password;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    @Override
    public String toString() {
        return "User [username=" + username + ", password="
                + Arrays.toString(password) + ", gender=" + gender + "]";
    }
     
     
}


public class Student {
    private int id;//BeanUtil对于基本类型自动转换
    private String name;
    private String password;
    private String gender;
    private boolean married;
    private String[] hobby;
    private String province;
    private String description;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public boolean isMarried() {
        return married;
    }
    public void setMarried(boolean married) {
        this.married = married;
    }
    public String[] getHobby() {
        return hobby;
    }
    public void setHobby(String[] hobby) {
        this.hobby = hobby;
    }
    public String getProvince() {
        return province;
    }
    public void setProvince(String province) {
        this.province = province;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", name=" + name + ", password="
                + password + ", gender=" + gender + ", married=" + married
                + ", hobby=" + Arrays.toString(hobby) + ", province="
                + province + ", description=" + description + "]";
    }
     
}


<form action="/day08_01_request/servlet/RequestDemo4" method="post">
        用户名:<input type="text" name="username"/><br/>
        密码:<input type="password" name="password"/><br/>
        确认密码:<input type="password" name="password"/><br/>
        性别:<input type="text" name="gender" value="male"/>
        <input type="submit" value="注册"/>
    </form>

4.  以输入流的形式接收请求正文:POST
  一般情况下用不着,文件上传时使用。


public class RequestDemo4 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        ServletInputStream in = request.getInputStream();
        int len = -1;
        byte b[] = new byte[1024];
        while((len=in.read(b))!=-1){
            System.out.println(new String(b,0,len));
        }
        in.close();
    }

 5.获取常用表单输入域的值
 type:radio checkbox   ,如果用户一个都没有选,客户端是根本不会传参数到服务器的。


public class RequestDemo5 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        test3(request,response);
    }
    //请求编码和响应编码没有关系
    private void test3(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");//设置请求正文的编码。只对POST有效
        Student s = new Student();
        System.out.println("封装前:"+s);
        try {
            BeanUtils.populate(s, request.getParameterMap());
        } catch (Exception e) {
            e.printStackTrace();
        }
         
        response.setContentType("text/html;charset=UTF-8");
         
        response.getWriter().write(s.toString());
    }
     
    //get请求方式的编码问题
    private void test2(HttpServletRequest request)
            throws UnsupportedEncodingException {
        String username = request.getParameter("name");//是二进制数据  %E6%9D%8E%E5%9B%9B
         
        byte b[] = username.getBytes("ISO-8859-1");
        username = new String(b,"UTF-8");
         
        System.out.println(username);//二进制转为字符,用ISO-8859-1的
         
    }
    //获取请求正文的参数乱码问题
    private void test1(HttpServletRequest request)
            throws UnsupportedEncodingException {
        request.setCharacterEncoding("UTF-8");//设置请求正文的编码。只对POST有效
         
        Student s = new Student();
        System.out.println("封装前:"+s);
        try {
            BeanUtils.populate(s, request.getParameterMap());
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("封装后:"+s);
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


<form action="/day08_01_request/servlet/RequestDemo5" method="post">
        <input type="hidden" value="438" name="id"/>
        <table border="1" width="438">
            <tr>
                <td>姓名</td>
                <td>
                    <input type="text" name="name"/>
                </td>
            </tr>
            <tr>
                <td>密码</td>
                <td>
                    <input type="password" name="password"/>
                </td>
            </tr>
            <tr>
                <td>性别</td>
                <td>
                    <input type="radio" name="gender" value="male" checked="checked"/>男性
                    <input type="radio" name="gender" value="female"/>女性
                </td>
            </tr>
            <tr>
                <td>婚否</td>
                <td>
                    <input type="checkbox" name="married"/>
                </td>
            </tr>
            <tr>
                <td>爱好</td>
                <td>
                    <input type="checkbox" name="hobby" value="eat"/>吃饭
                    <input type="checkbox" name="hobby" value="sleep"/>睡觉
                    <input type="checkbox" name="hobby" value="java"/>学Java
                </td>
            </tr>
            <tr>
                <td>籍贯</td>
                <td>
                    <select name="province">
                        <option value="BJ">北京</option>
                        <option value="SD">山东</option>
                        <option value="HB">湖北</option>
                    </select>
                </td>
            </tr>
            <!--
            <tr>
                <td>靓照</td>
                <td>
                    <input type="file" name="image"/>
                </td>
            </tr>
             -->
             <tr>
                <td>简介</td>
                <td>
                    <textarea rows="3" cols="38" name="description"></textarea>
                </td>
            </tr>
            <tr>
                <td colspan="2">
<!--                     <input type="submit" value="注册"/> -->
<!--                     <input type="image" src="an-0333.gif"/> -->
                    <input type="button" value="注册" onclick="toSubmit()"/>
                </td>
            </tr>
        </table>
        <script type="text/javascript">
            function toSubmit(){
                //验证用户的输入
                document.forms[0].submit();
            }
        </script>
    </form>

编码:

 

 

6.请求转发


//转发:源
//源和目标:共享请求范围中的数据
public class RequestDemo6 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setAttribute("p", "ppp");
        //ServletContext:地址的写法。必须以"/",代表当前应用。(应用开头的绝对路径)
//      RequestDispatcher rd = getServletContext().getRequestDispatcher("/servlet/RequestDemo7");
        //绝对路径
//      RequestDispatcher rd = request.getRequestDispatcher("/servlet/RequestDemo7");
        //相对路径
        RequestDispatcher rd = request.getRequestDispatcher("RequestDemo7");
        rd.forward(request, response);
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


//转发:目标
public class RequestDemo7 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String s = (String)request.getAttribute("p");//注意和getParameter没有关系
        response.getWriter().write(s);
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}

请求与重定向区别

 

7.//包含:源  服务器端行为


public class RequestDemo8 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        response.getWriter().write("我喜欢");
        RequestDispatcher rd = request.getRequestDispatcher("/servlet/RequestDemo9");
        rd.include(request, response);
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


public class RequestDemo9 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        response.getWriter().write("成都");
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}

 8.请求 和 包含 的小细节


//转发前后,源输出的任何响应正文无效
public class Forward1 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setHeader("Refresh", "1");
        System.out.println("转发前");
        response.getWriter().write("forward before");//转发前会清空响应对象中的正文内容
        request.getRequestDispatcher("/servlet/Forward2").forward(request, response);//转发
        System.out.println("转发后");
        response.getWriter().write("forward after");
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


//转发:目标
public class Forward2 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.getWriter().write("222222");//响应结束
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


//包含:源
//只会包含目标的正文,头部信息包含前清空
public class IncludeDemo1 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.getWriter().write("11111");
        request.getRequestDispatcher("/servlet/IncludeDemo2").include(request, response);
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


//包含:目标
public class IncludeDemo2 extends HttpServlet {
 
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setIntHeader("Refresh", 1);
        response.getWriter().write("22222");
    }
 
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
 
}


版权声明:本文内容由阿里云实名注册用户自发贡献,版权归原作者所有,阿里云开发者社区不拥有其著作权,亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容,填写侵权投诉表单进行举报,一经查实,本社区将立刻删除涉嫌侵权内容。

相关文章
网站流量日志埋点收集—后端脚本(nginx+lua)|学习笔记
快速学习网站流量日志埋点收集—后端脚本(nginx+lua)
0 0
网站流量日志分析--数据可视化--后端 web 工程整合搭建 | 学习笔记
快速学习网站流量日志分析--数据可视化--后端 web 工程整合搭建
0 0
网站流量日志分析--数据可视化--后端 web 工程架构 | 学习笔记
快速学习网站流量日志分析--数据可视化--后端 web 工程架构
0 0
总结项目技术点(后端技术3)| 学习笔记
快速学习 总结项目技术点(后端技术3)
0 0
总结项目技术点(后端技术2)| 学习笔记
快速学习 总结项目技术点(后端技术2)
0 0
总结项目技术点(后端技术1)| 学习笔记
快速学习 总结项目技术点(后端技术1)
0 0
阿里云 SLB 的创建及后端服务器的添加 | 学习笔记
快速学习阿里云 SLB 的创建及后端服务器的添加
0 0
讲师管理-上传讲师头像(后端接口实现) | 学习笔记
快速学习讲师管理-上传讲师头像(后端接口实现)
0 0
讲师管理-上传讲师头像(后端接口完善) | 学习笔记
快速学习讲师管理-上传讲师头像(后端接口完善)
0 0
+关注
loveincode
勤奋上进
文章
问答
文章排行榜
最热
最新
相关电子书
更多
机器学习在互联网后端技术中的应用
立即下载
机器学习在互联网后端技术中的应用
立即下载
低代码开发师(初级)实战教程
立即下载