/********************************************************servlet頁面****************************************************************/
package request;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
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;
import org.apache.commons.beanutils.BeanUtils;
import bean.User;
import com.sun.org.apache.regexp.internal.REUtil;
//獲取請求頭
//獲取請求數據的時候一般都要先檢查，再使用
public class RequestDemo2 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//獲取客戶端超鏈接或表單提交過來的數據
//1，直接獲取
String value = request.getParameter("username");
//先判斷value的值是否符合要求，再使用
if(value!=null && !value.trim().equals(""))
System.out.println(value);
System.out.println("--------------");
//通過提交數據的名稱獲得值
//2，先得到所有名稱，再根據名稱獲得值
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,獲取指定名稱的所有值
String[] values = request.getParameterValues("username");
//這樣寫程序健壯性不夠，如果客戶機表單沒有填寫數據就提交，此時values就為空
//執行下面的語句就會報空指針異常
// for(String v:values){
// System.out.println(v);
// }
//這樣寫，才不會報措
for(int i=0;values!=null && i<values.length;i++){
System.out.println(values[i]);
}
//4
Map map = request.getParameterMap();
User user = new User();
try {
BeanUtils.populate(user, map);
} catch (Exception e1) {
e1.printStackTrace();
}
System.out.println(user);
}
//獲取頭相關的數據
private void test1(HttpServletRequest request) {
//獲取頭信息
//1
String headValue = request.getHeader("Accept-Encoding");
System.out.println(headValue);
System.out.println("-----------------------");
//2
Enumeration e = request.getHeaders("Accept-Encoding");
while(e.hasMoreElements()){
String value = (String) e.nextElement();
System.out.println(value);
}
System.out.println("-----------------");
//3
e = request.getHeaderNames();
while (e.hasMoreElements()) {
String name = (String) e.nextElement();
String value = request.getHeader("name");
System.out.println(value);
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
/********************************************************html頁面**********************************************************************************/
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>提交數據</title>
</head>
<body>
<!-- 超鏈接給服務端帶數據 -->
<a href="/requestandresponse/RequestDemo2?username=xxxxxx">點點</a>
<!-- 表單給服務器帶數據 -->
<form action="/requestandresponse/RequestDemo2" method="post">
用戶名：<input type="text" name="username"/>
<input type="submit" value="提交">
</form>
</body>
</html>