try {
						PrintWriter out = response.getWriter();
						//输出
						out.print("用户名或密码错误！");
						//out.flush();
						out.close();
						
					} catch (IOException e) {
						e.printStackTrace();
					}

改了以后就是这样的

try {

PrintWriter out = response.getWriter();//输出

out.print("用户名或密码错误！");

//out.flush();

out.close();return;//就是这行

} catch (IOException e)

{

e.printStackTrace();

}