四种通用的获取请求数据方法getParameter（常用）
代码块如下：
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Set;
@WebServlet("/test01")
public class test01_Servlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//通过getParameter（键名）来获取参数值，get，post通用
String username = request.getParameter("username");
System.out.println(username);
//通过键名获取第一个参数值value
String what = request.getParameter("what");
System.out.println("什么:"+what);
//通过键名获取所有的参数值
String[] pm = request.getParameterValues("what");
for (String s : pm) {
System.out.println(s);
}
System.out.println("---------");
//访问该Servlet中的所有键名name
Enumeration<String> pms = request.getParameterNames();
while (pms.hasMoreElements()){
String s = pms.nextElement();
System.out.println(s);
}
System.out.println("---------");
//获取所有参数的map集合
Map<String, String[]> pam = request.getParameterMap();
Set<String> keySet = pam.keySet();
for (String key : keySet) {
String[] values = pam.get(key);
for (String value : values) {
System.out.println(key+"---"+value);
}
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>get post通用</title>
</head>
<body>
<form action="/test01" method="get">
<input type="text" placeholder="请输入用户名" name="username" ><br>
<input type="text" placeholder="请输入密码" name="password" ><br>
<input type="text" placeholder="请输入账号" name="id" ><br>
<input type="checkbox" value="hhh" name="what">哈哈
<input type="checkbox" value="www" name="what">喔喔
<input type="submit" value="提交">
</form>
</body>
</html>
运行结果如下：
