zoukankan html css js c++ java

第一个web程序（ServletRequest ， ServletResponse）

一.ServletRequest

1.获取参数的方法（四种）

　　> String getParameter(String name): 根据请求参数的名字, 返回参数值.
　　　　若请求参数有多个值(例如 checkbox), 该方法只能获取到第一个提交的值.

　　> String[] getParameterValues(String name): 根据请求参数的名字, 返回请求参数对应的字符串数组.

　　> Enumeration getParameterNames(): 返回参数名对应的 Enumeration 对象,
　　类似于 ServletConfig(或 ServletContext) 的 getInitParameterNames() 方法.

　　> Map getParameterMap(): 返回请求参数的键值对: key: 参数名, value: 参数值, String 数组类型.

2.程序indexhtml

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4 <meta charset="UTF-8">
 5 <title>Insert title here</title>
 6 </head>
 7 <body>
 8 <form action="login" method="post">
 9         user: <input type="text" name="user"/>
10         password: <input type="password" name="password"/><br><br>
11         
12         interesting:
13         <input type="checkbox" name="interesting" value="reading"/>Reading
14         <input type="checkbox" name="interesting" value="game"/>Game
15         <input type="checkbox" name="interesting" value="party"/>Party
16         <input type="checkbox" name="interesting" value="shopping"/>Shopping
17         <input type="checkbox" name="interesting" value="sport"/>Sport
18         <input type="checkbox" name="interesting" value="tv"/>TV
19         
20         <input type="submit" value="Submit"/>
21     </form>
22 </body>
23 </html>

3.web.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3     xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 4     xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
 5     id="WebApp_ID" version="3.1">
 6     <servlet>
 7         <servlet-name>LoginServlet</servlet-name>
 8         <servlet-class>servlets.LoginServlet</servlet-class>
 9     </servlet>
10     <servlet-mapping>
11         <servlet-name>LoginServlet</servlet-name>
12         <url-pattern>/login</url-pattern>
13     </servlet-mapping>
14 </web-app>

4.LoginServlet.java

 1 package servlets;
 2 
 3 import java.io.IOException;
 4 import java.util.Arrays;
 5 import java.util.Enumeration;
 6 import java.util.Map;
 7 
 8 import javax.servlet.Servlet;
 9 import javax.servlet.ServletConfig;
10 import javax.servlet.ServletException;
11 import javax.servlet.ServletRequest;
12 import javax.servlet.ServletResponse;
13 
14 public class LoginServlet implements Servlet{
15     public void destroy() {}
16     public ServletConfig getServletConfig() {
17         return null;
18     }
19     public String getServletInfo() {
20         return null;
21     }
22     public void init(ServletConfig arg0) throws ServletException {}
23     public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
24         //getParameter
25         String name=request.getParameter("user");
26         System.out.println("user="+name);
27         System.out.println("=========================");
28         
29         //getParameterValues
30         String[] names=request.getParameterValues("interesting");
31         for(String inter:names) {
32             System.out.println("inter="+inter);
33         }
34         System.out.println("=========================");
35         
36         //getParameterNames
37         Enumeration<String> en=request.getParameterNames();
38         while(en.hasMoreElements()) {
39             String enName=en.nextElement();
40             System.out.println("enName="+enName);
41         }
42         System.out.println("=========================");
43         
44         //getParameterMap
45         Map<String,String[]> map=request.getParameterMap();
46         for(Map.Entry<String,String[]> entry : map.entrySet()) {
47             System.out.println(entry.getKey()+"="+Arrays.asList(entry.getValue()));
48         }
49         
50     }
51 
52 }

5.效果

6.获取请求的 URI

7.获取请求方式

8.若是一个 GET 请求, 获取请求参数对应的那个字符串, 即 ? 后的那个字符串.

9.获取请求的 Serlvet 的映射路径

10.java程序

 1 package servlets;
 2 
 3 import java.io.IOException;
 4 import java.util.Arrays;
 5 import java.util.Enumeration;
 6 import java.util.Map;
 7 
 8 import javax.servlet.Servlet;
 9 import javax.servlet.ServletConfig;
10 import javax.servlet.ServletException;
11 import javax.servlet.ServletRequest;
12 import javax.servlet.ServletResponse;
13 import javax.servlet.http.HttpServletRequest;
14 
15 public class LoginServlet implements Servlet{
16     public void destroy() {}
17     public ServletConfig getServletConfig() {
18         return null;
19     }
20     public String getServletInfo() {
21         return null;
22     }
23     public void init(ServletConfig arg0) throws ServletException {}
24     public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
25 //        //getParameter
26 //        String name=request.getParameter("user");
27 //        System.out.println("user="+name);
28 //        System.out.println("=========================");
29 //        
30 //        //getParameterValues
31 //        String[] names=request.getParameterValues("interesting");
32 //        for(String inter:names) {
33 //            System.out.println("inter="+inter);
34 //        }
35 //        System.out.println("=========================");
36 //        
37 //        //getParameterNames
38 //        Enumeration<String> en=request.getParameterNames();
39 //        while(en.hasMoreElements()) {
40 //            String enName=en.nextElement();
41 //            System.out.println("enName="+enName);
42 //        }
43 //        System.out.println("=========================");
44 //        
45 //        //getParameterMap
46 //        Map<String,String[]> map=request.getParameterMap();
47 //        for(Map.Entry<String,String[]> entry : map.entrySet()) {
48 //            System.out.println(entry.getKey()+"="+Arrays.asList(entry.getValue()));
49 //        }
50         
51         //HttpServletRequest(负责http的Servlet)
52         HttpServletRequest hsr=(HttpServletRequest) request;
53         
54         //getRequestURI
55         String requestUri=hsr.getRequestURI();
56         System.out.println("requestUri="+requestUri);
57         System.out.println("=========================");
58         
59         //getMethod
60         String method=hsr.getMethod();
61         System.out.println("method="+method);
62         System.out.println("=========================");
63         
64         //getQueryString
65         String queryString =hsr.getQueryString();
66         System.out.println("queryString="+queryString);
67         System.out.println("=========================");
68         
69         //getServletPath
70         String servletPath=hsr.getServletPath();
71         System.out.println("servletPath="+servletPath);
72         System.out.println("=========================");
73         
74         //
75     }
76 
77 }

11.效果

二：response

1.将字放到html里

 1 package servlets;
 2 
 3 import java.io.IOException;
 4 import java.io.PrintWriter;
 5 import java.util.Arrays;
 6 import java.util.Enumeration;
 7 import java.util.Map;
 8 
 9 import javax.servlet.Servlet;
10 import javax.servlet.ServletConfig;
11 import javax.servlet.ServletException;
12 import javax.servlet.ServletRequest;
13 import javax.servlet.ServletResponse;
14 import javax.servlet.http.HttpServletRequest;
15 
16 public class LoginServlet implements Servlet{
17     public void destroy() {}
18     public ServletConfig getServletConfig() {
19         return null;
20     }
21     public String getServletInfo() {
22         return null;
23     }
24     public void init(ServletConfig arg0) throws ServletException {}
25     public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
26 //        //getParameter
27 //        String name=request.getParameter("user");
28 //        System.out.println("user="+name);
29 //        System.out.println("=========================");
30 //        
31 //        //getParameterValues
32 //        String[] names=request.getParameterValues("interesting");
33 //        for(String inter:names) {
34 //            System.out.println("inter="+inter);
35 //        }
36 //        System.out.println("=========================");
37 //        
38 //        //getParameterNames
39 //        Enumeration<String> en=request.getParameterNames();
40 //        while(en.hasMoreElements()) {
41 //            String enName=en.nextElement();
42 //            System.out.println("enName="+enName);
43 //        }
44 //        System.out.println("=========================");
45 //        
46 //        //getParameterMap
47 //        Map<String,String[]> map=request.getParameterMap();
48 //        for(Map.Entry<String,String[]> entry : map.entrySet()) {
49 //            System.out.println(entry.getKey()+"="+Arrays.asList(entry.getValue()));
50 //        }
51         //******************************************************************//
52 //        //HttpServletRequest(负责http的Servlet)
53 //        HttpServletRequest hsr=(HttpServletRequest) request;
54 //        
55 //        //getRequestURI
56 //        String requestUri=hsr.getRequestURI();
57 //        System.out.println("requestUri="+requestUri);
58 //        System.out.println("=========================");
59 //        
60 //        //getMethod
61 //        String method=hsr.getMethod();
62 //        System.out.println("method="+method);
63 //        System.out.println("=========================");
64 //        
65 //        //getQueryString
66 //        String queryString =hsr.getQueryString();
67 //        System.out.println("queryString="+queryString);
68 //        System.out.println("=========================");
69 //        
70 //        //getServletPath
71 //        String servletPath=hsr.getServletPath();
72 //        System.out.println("servletPath="+servletPath);
73 //        System.out.println("=========================");
74         //******************************************************************//
75         //response
76 //        response.setContentType("text/html");
77 //        response.setContentType("text/msdoc");
78         PrintWriter out = response.getWriter();
79         out.println("helloworld...");        
80     }
81 
82 }

2.效果

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原文地址：https://www.cnblogs.com/juncaoit/p/7384904.html