获取客户机带过来的数据

雨点打透心脏的1/2处 2022-05-16 06:17 127阅读 0赞

package cn.itcast.request;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.Enumeration;
    import java.util.Map;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    //获取客户机带过来的数据
    public class RequestDemo3 extends HttpServlet {
        
    
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
    
            //1.
            //http://localhost:8080/day06/servlet/RequestDemo3?name=xxx
            String value = request.getParameter("name");
            System.out.println(value);
    
            System.out.println("-----");
    
    
            //2.
            //http://localhost:8080/day06/servlet/RequestDemo3?name=xxx&password=123
            Enumeration e = request.getParameterNames();
            while(e.hasMoreElements()){
                String name = (String) e.nextElement();
                value = request.getParameter(name);
                System.out.println(name + "=" + value );
            }
    
            System.out.println("----");
    
            //3.
            //http://localhost:8080/day06/servlet/RequestDemo3?name=xxx&name=yyyy
            String values[] = request.getParameterValues("name");
            /*if(values!=null){
                for(String value1 : values){
                    System.out.println(value1);
                }
            }*/
            for(int i=0;values!=null && i<values.length;i++){   //这样的代码可以预防null指针的问题
                System.out.println(values[i]);
            }
    
    
            System.out.println("--map--");
            //4.
            // http://localhost:8080/day06/servlet/RequestDemo3?a=1&a=2&b=1
            Map<String,String[]> map = request.getParameterMap();  //a=1&a=2&b=1
            for(Map.Entry<String, String[]> entry : map.entrySet()){
                String name  = entry.getKey();
                values = entry.getValue();   //[]
                for(int i=0;values!=null && i<values.length;i++){
                    value = values[i];
                    System.out.println(name + "=" + value);
                }
            }
    
            //通过流获取
            InputStream in = request.getInputStream();  //这种方式只用在文件上传上
        }
    
        public void doPost(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            doGet(request, response);
        }
    
    }