Java 如何将请求从jsp重定向到servlet_Java_Jsp_Servlets

Java 如何将请求从jsp重定向到servlet

java jsp servlets

Java 如何将请求从jsp重定向到servlet,java,jsp,servlets,Java,Jsp,Servlets,提前谢谢你的帮助。我正在尝试使用单选按钮对象从jsp获取答案，然后发送到一个servlet，该servlet将管理请求并发送到特定的servlet以影响数据库。我在管理请求的servlet中遇到问题。我无法将请愿书重新发送到最终servlet。源代码的部分如下所示： PolicyManager.jsp： <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859

提前谢谢你的帮助。我正在尝试使用单选按钮对象从jsp获取答案，然后发送到一个servlet，该servlet将管理请求并发送到特定的servlet以影响数据库。我在管理请求的servlet中遇到问题。我无法将请愿书重新发送到最终servlet。源代码的部分如下所示：

PolicyManager.jsp：

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
    <h1>Change the current policy</h1>
     <form action="ManageRequest" method="Post">
        Which action would you like to apply?<br><br>
        <input type="radio" name="policy" value="add">Add<br>
        <input type="radio" name="policy" value="delete">Delete
        <br><br>
        <input type="submit" value="submit"/>       
     </form>

</body>
</html>


在此处插入标题
更改当前策略
您希望应用哪个操作？


添加

删去

ManageRequest.java：

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

/**
 * Servlet implementation class ManageRequest
 */
@WebServlet("/ManageRequest")
public class ManageRequest extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public ManageRequest() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        printWriter.print("doGet method");
        String policy=request.getParameter("policy");

        if (policy.equals("add") ) {
            printWriter.println("<html><body>Redirecting to Add servlet section..."+"<br>");
            RequestDispatcher dispatcher = request.getRequestDispatcher("/AddPolicy");
            dispatcher.forward(request, response);

        } else if (policy.equals("delete")) {
            printWriter.println("<html><body>Redirectin to Delete servlet section..."+"<br>");
            RequestDispatcher dispatcher = request.getRequestDispatcher("/DeletePolicy");
            dispatcher.forward(request, response);

        }
        else{
            printWriter.println("<html><body>A different option..."+"<br>");
        }
        printWriter.println("</body></html>");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        String policy=request.getParameter("policy");
        printWriter.print("doPost method");

        if (policy.equals("add") ) {
            printWriter.println("<html><body>Redirecting to Add servlet section..."+"<br>");
            RequestDispatcher dispatcher = request.getRequestDispatcher("/AddPolicy");
            dispatcher.forward(request, response);

        } else if (policy.equals("delete")) {
            printWriter.println("<html><body>Redirectin to Delete servlet section..."+"<br>");
            RequestDispatcher dispatcher = request.getRequestDispatcher("/DeletePolicy");
            dispatcher.forward(request, response);

        }
        else{
            printWriter.println("<html><body>A different option..."+"<br>");
        }
        printWriter.println("</body></html>");

    }

}

import java.io.IOException；
导入java.io.PrintWriter；
导入javax.servlet.RequestDispatcher；
导入javax.servlet.ServletContext；
导入javax.servlet.ServletException；
导入javax.servlet.annotation.WebServlet；
导入javax.servlet.http.HttpServlet；
导入javax.servlet.http.HttpServletRequest；
导入javax.servlet.http.HttpServletResponse；
/**
*Servlet实现类ManageRequest
*/
@WebServlet（“/ManageRequest”）
公共类ManageRequest扩展了HttpServlet{
私有静态最终长serialVersionUID=1L；
/**
*@参见HttpServlet#HttpServlet（）
*/
公共管理请求（）{
超级（）；
//TODO自动生成的构造函数存根
}
/**
*@参见HttpServlet#doGet（HttpServletRequest请求，HttpServletResponse响应）
*/
受保护的void doGet（HttpServletRequest请求，HttpServletResponse响应）抛出ServletException，IOException{
//TODO自动生成的方法存根
PrintWriter PrintWriter=response.getWriter（）；
printWriter.print（“doGet方法”）；
字符串策略=request.getParameter（“策略”）；
if（policy.equals（“add”））{
printWriter.println（“重定向到添加servlet节…”+“
”；
RequestDispatcher=request.getRequestDispatcher（“/AddPolicy”）；
转发（请求、响应）；
}else if（policy.equals（“delete”））{
printWriter.println（“重定向到删除servlet节…”+“
”；
RequestDispatcher=request.getRequestDispatcher（“/DeletePolicy”）；
转发（请求、响应）；
}
否则{
printWriter.println（“另一个选项…”+“
”；
}
printWriter.println（“”）；
}
/**
*@请参阅HttpServlet#doPost（HttpServletRequest请求，HttpServletResponse响应）
*/
受保护的void doPost（HttpServletRequest请求、HttpServletResponse响应）引发ServletException、IOException{
//TODO自动生成的方法存根
PrintWriter PrintWriter=response.getWriter（）；
字符串策略=request.getParameter（“策略”）；
printWriter.print（“doPost方法”）；
if（policy.equals（“add”））{
printWriter.println（“重定向到添加servlet节…”+“
”；
RequestDispatcher=request.getRequestDispatcher（“/AddPolicy”）；
转发（请求、响应）；
}else if（policy.equals（“delete”））{
printWriter.println（“重定向到删除servlet节…”+“
”；
RequestDispatcher=request.getRequestDispatcher（“/DeletePolicy”）；
转发（请求、响应）；
}
否则{
printWriter.println（“另一个选项…”+“
”；
}
printWriter.println（“”）；
}
}

AddPolicy.java：

package PolicyManager;

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;

/**
 * Servlet implementation class AddPolicy
 */
@WebServlet("/AddPolicy")
public class AddPolicy extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public AddPolicy() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        printWriter.println("<h1>Add Policy</h1>");
        printWriter.println("Add Policy");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

package PolicyManager;

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;

/**
 * Servlet implementation class DeletePolicy
 */
@WebServlet("/DeletePolicy")
public class DeletePolicy extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public DeletePolicy() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        printWriter.println("<h1>Delete Policy</h1>");
        printWriter.println("Delete Policy");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

包策略管理器；
导入java.io.IOException；
导入java.io.PrintWriter；
导入javax.servlet.ServletException；
导入javax.servlet.annotation.WebServlet；
导入javax.servlet.http.HttpServlet；
导入javax.servlet.http.HttpServletRequest；
导入javax.servlet.http.HttpServletResponse；
/**
*Servlet实现类AddPolicy
*/
@WebServlet（“/AddPolicy”）
公共类AddPolicy扩展了HttpServlet{
私有静态最终长serialVersionUID=1L；
/**
*@参见HttpServlet#HttpServlet（）
*/
公共政策（）{
超级（）；
//TODO自动生成的构造函数存根
}
/**
*@参见HttpServlet#doGet（HttpServletRequest请求，HttpServletResponse响应）
*/
受保护的void doGet（HttpServletRequest请求，HttpServletResponse响应）抛出ServletException，IOException{
//TODO自动生成的方法存根
PrintWriter PrintWriter=response.getWriter（）；
printWriter.println（“添加策略”）；
printWriter.println（“添加策略”）；
}
/**
*@请参阅HttpServlet#doPost（HttpServletRequest请求，HttpServletResponse响应）
*/
受保护的void doPost（HttpServletRequest请求、HttpServletResponse响应）引发ServletException、IOException{
//TODO自动生成的方法存根
}
}

DeletePolicy.java：

package PolicyManager;

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;

/**
 * Servlet implementation class AddPolicy
 */
@WebServlet("/AddPolicy")
public class AddPolicy extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public AddPolicy() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        printWriter.println("<h1>Add Policy</h1>");
        printWriter.println("Add Policy");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

package PolicyManager;

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;

/**
 * Servlet implementation class DeletePolicy
 */
@WebServlet("/DeletePolicy")
public class DeletePolicy extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public DeletePolicy() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        PrintWriter printWriter = response.getWriter();
        printWriter.println("<h1>Delete Policy</h1>");
        printWriter.println("Delete Policy");
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

包策略管理器；
导入java.io.IOException；
导入java.io.PrintWriter；
导入javax.servlet.ServletException；
导入javax.servlet.annotation.WebServlet；
导入javax.servlet.http.HttpServlet；
导入javax.servlet.http.HttpServletRequest；
导入javax.servlet.http.HttpServletResponse；
/**
*Servlet实现类DeletePolicy
*/
@WebServlet（“/DeletePolicy”）
公共类DeletePolicy扩展了HttpServlet{
私有静态最终长serialVersionUID=1L；
/**
*@参见HttpServlet#HttpServlet（）
*/
公共政策（）{
超级（）；
//TODO自动生成的构造函数存根
}
/**
*@参见HttpServlet#doGet（HttpServletRequest请求，HttpServletResponse响应）
*/
受保护的void doGet（HttpServletRequest请求，HttpServletResponse响应）抛出ServletException，IOException{
//TODO自动生成的方法存根
PrintWriter PrintWriter=response.getWriter（）；
printWriter.println（“删除策略”）；
printWriter.println（“删除策略”）；
}
/**