入門servlet：request獲取請求參數通用方式

一、獲取請求參數通用方式

1.　String getParameter(String name)：根據參數名稱獲取參數值　例：username=flypig&password=2343

2.　String[] getParameterValues(String name)：根據參數名稱獲取參數值的數組　　例：hooby=xx&hobby=name

3.　Enumeration<String> getParameterNames()：獲取所有請求的參數名稱

4.　Map<String, String[]> getParameterMap()：獲取所有參數的map集合

@WebServlet("/RequestDemo6")
public class RequestDemo6 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //post 獲取請求參數

        //根據參數名稱獲取參數值
        String username = request.getParameter("username");
//        System.out.println("post");
//        System.out.println(username);

        //根據參數名稱獲取參數值的數組
        String[] hobbies = request.getParameterValues("hobby");
//        for (String hobby : hobbies) {
//            System.out.println(hobby);
//        }

        //獲取所有請求的參數名稱

        Enumeration<String> parameterNames = request.getParameterNames();
//        while(parameterNames.hasMoreElements()){
//            String name = parameterNames.nextElement();
//            System.out.print(name+":");
//            String value = request.getParameter(name);
//            System.out.println(value);
//        }

        //獲取所有參數的map集合
        Map<String, String[]> parameterMap = request.getParameterMap();
        //遍歷
        Set<String> keySet = parameterMap.keySet();
        for (String name : keySet){

            //根據鍵獲取值
            String[] values = parameterMap.get(name);
            System.out.println(name);
            for (String value : values) {
                System.out.println(value);
            }
            System.out.println("--------------");
        }


    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //get獲取請求參數

        //根據參數名稱獲取參數值
//        String username = request.getParameter("username");
//        System.out.println("get");
//        System.out.println(username);

        this.doPost(request,response);
    }
}

 

二、解決亂碼問題

解決請求參數中文亂碼問題：

　　* get方式：tomcat 8已經將get方式亂碼問題解決

　　* post方式：會亂碼

　　　　*解決：在獲取參數前，設置request的編碼request.setCharacterEncoding("utf-8")

@WebServlet("/RequestDemo7")
public class RequestDemo7 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //設置流的編碼
        request.setCharacterEncoding("utf-8");

        //post 獲取請求參數username
        String username = request.getParameter("username");
        System.out.println(username);

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //get獲取請求參數

        //根據參數名稱獲取參數值
//        String username = request.getParameter("username");
//        System.out.println("get");
//        System.out.println(username);

        this.doPost(request,response);
    }
}