userservlet.java

Ajax的使用方法

package demo;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class UserServlet extends HttpServlet{
	public void service(HttpServletRequest req,HttpServletResponse res)throws IOException,ServletException{
		res.setContentType("text/html;charset=utf-8");//设置响应格式及其编码
		String username = req.getParameter("username");
		PrintWriter out = res.getWriter();
		if("adam".equals(username)){
			out.print("false");//如果名字是adam
							   //则表示该用户已
							   //存在
		}else{
			out.print("true");
		}
		out.close();
	}
}