package request;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//forward的细节
public class RequestDemo6 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String data="aaaaa";
PrintWriter writer = response.getWriter();
writer.write(data);
writer.close();
//以下会导致:java.lang.IllegalStateException: Cannot forward after response has been committed
request.getRequestDispatcher("/message.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
java.lang.IllegalStateException: Cannot forward after response has been committed
【解析】:foward之前不要往response里面写数据。