Servlet的request学习笔记

1 System.out.println(request.getMethod());            //请求方式
2 System.out.println(request.getRequestURL());        //请求完整网址
3 System.out.println(request.getRequestURI());        //请求的资源网址
4 System.out.println(request.getContextPath());        //请求的资源名
5 System.out.println(request.getQueryString());        //请求的参数列表

1     Enumeration names = request.getHeaderNames();
2     while(names.hasMoreElements()) {
3         //获取所有的头部信息    
4         String name = (String) names.nextElement();
5         System.out.println(name+":"+request.getHeader(name));
6     }    

1     //获取单个头部信息
2     System.out.println(request.getHeader("user-agent"));

 1     private void demo1(HttpServletRequest request) {
 2                 //第一种方式，分别单独获取
 3         String userName = request.getParameter("userName");
 4         String password = request.getParameter("password");
 5         String gender = request.getParameter("gender");
 6                 //复选的要用数组接受,用getParameterValues()
 7         String[] hobby = request.getParameterValues("hobby");
 8         String city = request.getParameter("city");
 9         
10         System.out.println(userName);
11         System.out.println(password);
12         System.out.println(gender);
13         for (int i = 0; hobby!=null && i < hobby.length; i++) {
14             System.out.println(hobby[i]);
15         }
16         System.out.println(city);
17     }

 1     private void demo2(HttpServletRequest request) {
 2         //第二种方式，先获取遍历名字，再分别找到
 3         Enumeration data = request.getParameterNames();
 4         while(data.hasMoreElements()){
 5             String str = (String) data.nextElement();
 6             String[] user = request.getParameterValues(str);
 7             System.out.print(str+"\t");
 8             for (int i = 0; user!=null && i < user.length; i++) {
 9                 System.out.print(user[i]);
10             }
11             System.out.println();
12         }
13     }

 1     private void demo3(HttpServletRequest request) {
 2         //第三种方式并存入User对象中
 3         Map<String,String[]> map = request.getParameterMap();
 4         User user = new User();
 5         System.out.println(user);
 6         for (Entry<String, String[]> data : map.entrySet()) {
 7             String key = data.getKey();
 8             String[] value = data.getValue();
 9             try {
10                 //使用了内省
11                 PropertyDescriptor pd = new PropertyDescriptor(key, user.getClass());
12                 //得到相应的set方法
13                 Method setter = pd.getWriteMethod();
14                 if(value.length == 1) {
15                     //使用invoke执行相应的方法并指定参数
16                     setter.invoke(user, value[0]);
17                 } else {
18                     //把数组当成一个完整参数传入
19                     setter.invoke(user, (Object)value);
20                 }
21             } catch (Exception e) {
22                 // TODO Auto-generated catch block
23                 e.printStackTrace();
24             }
25         }
26         System.out.println(user);
27     }

        User user = new User();
        //使用了导入的commons-beanutils-1.8.3.jar和commons-logging-1.1.1.jar
        BeanUtils bu = new BeanUtils();
        try {
            //自动的将表单的数据按照map集合demo3的那种形势set入user
            bu.populate(user, request.getParameterMap());
            System.out.println(user);
        } catch (Exception e) {
            e.printStackTrace();
        }

1　       //带非表单数据转发
2         request.setAttribute("name", "张三");
3         request.getRequestDispatcher("/servlet/RequestDemo6").forward(request, response);
4
5　　　　　// /servlet/RequestDemo6中取得数据
6　　　　　String s = (String) request.getAttribute("name");