2020年1月6日 星期一

Java RWD Web企業網站開發指南 使用Spring MVC與Bootstrap 程式練習 WCD01/course.c01.HelloServlet

Java RWD Web企業網站開發指南 使用Spring MVC與Bootstrap
程式練習 WCD01/course.c01.HelloServlet


茶包碎碎念
匯入第一個專案就發現執行錯誤


讓我們看看錯誤原因
Caused by: java.lang.IllegalArgumentException: The servlets named [HelloServlet] and [HelloServlet] are both mapped to the url-pattern [/HelloServlet] which is not permitted

再看看程式碼


package course.c01;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "HelloServlet", urlPatterns = { "/HelloServlet", "/HelloServlet" })
public class HelloServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        System.out.println();
        try {
            out.println("<html>");
            out.println("<head>");
            out.println("<title>HelloServlet</title>");
            out.println("</head>");
            out.println("<body>");
            out.println("<h1>HelloServlet says \"Hello, World!\"</h1>");
            out.println("</body>");
            out.println("</html>");
        } finally {
            out.close();
        }
    }
}


發現了錯誤了沒!!!
兩個一樣的 urlPatterns
移除一個
或是 改名
Tomcat 就沒有報錯
就會正常跑了。

我們再來看看 範例的 servlet


感謝收看
本次的 hello servelet



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