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
时间： 2024-10-27 01:56:32