servlet處理http請求7

客戶端發送請求的方式
1.地址欄直接輸入url
2.超鏈接指定的url
3.表單form的action指定的url
4.js的location.href指定url
如果要想獲取http請求的參數就需要明白HttpServletRequest接口，這個接口處理http請求
由容器實現，開發中直接從domethod的參數中獲取實例
獲取請求參數的方法：
使用HttpServletRequest提供的方法獲取參數
getParameter
getParameterValues 返回數組
getParameterNames 獲取所有參數名
getParameterMap 獲取所有參數名與參數值
如果表單有指定屬性enctyoe=“multipart/from-data”,則以上方法無效
超鏈接來傳值

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String name = request.getParameter("name");
        String gender = request.getParameter("gender");
        System.out.println(name);
        System.out.println(gender);
        System.out.println("--------------------");
        String[] names = request.getParameterValues("name");
        for (String n : names) {
            System.out.println(n);
        }
        System.out.println("--------------------");
        Enumeration<String> params = request.getParameterNames();
        while (params.hasMoreElements()) {
            String param = params.nextElement();
            System.out.println(param + ":" + request.getParameter(param));
        }
        System.out.println("--------------------");
        Map<String, String[]> map = request.getParameterMap();
        Set<String> keys=map.keySet();
        for (String key : keys) {
            System.out.println(key+":"+map.get(key));
        }
    }

表單來獲取

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        request.setCharacterEncoding("UTF-8");
        String userName = request.getParameter("username");
        System.out.println(userName);
        System.out.println(request.getParameter("userpwd"));
        System.out.println(request.getParameter("gender"));
        String[] favors = request.getParameterValues("favors");
        if (favors != null) {
            for (String favor : favors) {
                System.out.println(favor);
            }
        }
        System.out.println(request.getParameter("cities"));
        System.out.println(request.getParameter("description"));
        System.out.println("--------------------");
        Enumeration<String> params = request.getParameterNames();
        while (params.hasMoreElements()) {
            String param = params.nextElement();
            System.out.println(param + ":" + request.getParameter(param));
        }
        System.out.println("--------------------");
        Map<String, String[]> map = request.getParameterMap();
        Set<String> keys=map.keySet();
        for (String key : keys) {
            System.out.println(key+":"+map.get(key));
        }
    }

request.setCharacterEncoding(“UTF-8”);解決中文亂碼問題，且要加載最前面