servlet及jsp之间的请求转发

2022-11-14 14:43:36

1、servlet间的请求转发

  <dependencies>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>javax.servlet-api</artifactId>

      <version>3.1.0</version>

      <scope>provided</scope>

    </dependency>

  </dependencies>

  <build>

    <finalName>servlet-demo</finalName>

    <plugins>

      <plugin>

        <groupId>org.mortbay.jetty</groupId>

        <artifactId>jetty-maven-plugin</artifactId>

        <version>8.1.16.v20140903</version>

        <configuration>

          <scanIntervalSeconds>10</scanIntervalSeconds>

          <connectors>

            <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">

              <port>7777</port>

            </connector>

          </connectors>

          <webAppConfig>

            <contextPath>/</contextPath>

          </webAppConfig>

        </configuration>

      </plugin>

    </plugins>

  </build>

pom.xml

package com.test;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@WebServlet("/myServlet")

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        RequestDispatcher requestDispatcher = request.getRequestDispatcher("myServlet2");

        requestDispatcher.forward(request, response);

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet

package com.demo;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@WebServlet("/myServlet2")

public class MyServlert2 extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.getWriter().write("I am Servlet2");

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet2

myServlet和myServlet2在不同的包，但请求转发时不需要使用—— ../ 之类的相对路径，会自动寻找到适合的Servlet

2、servlet转发到jsp

  <dependencies>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>javax.servlet-api</artifactId>

      <version>3.1.0</version>

      <scope>provided</scope>

    </dependency>

  </dependencies>

  <build>

    <finalName>servlet-demo</finalName>

    <plugins>

      <plugin>

        <groupId>org.mortbay.jetty</groupId>

        <artifactId>jetty-maven-plugin</artifactId>

        <version>8.1.16.v20140903</version>

        <configuration>

          <scanIntervalSeconds>10</scanIntervalSeconds>

          <connectors>

            <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">

              <port>7777</port>

            </connector>

          </connectors>

          <webAppConfig>

            <contextPath>/</contextPath>

          </webAppConfig>

        </configuration>

      </plugin>

    </plugins>

  </build>

pom.xml

package com.test;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@WebServlet("/myServlet")

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        RequestDispatcher requestDispatcher = request.getRequestDispatcher("/WEB-INF/my.jsp");

        requestDispatcher.forward(request, response);

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet

<html>

<body>

<h2>Hello World! I am Mike</h2>

</body>

</html>

my.jsp

3、jsp里使用java代码转发到servlet

  <dependencies>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>javax.servlet-api</artifactId>

      <version>3.1.</version>

      <scope>provided</scope>

    </dependency>

    <dependency>

      <groupId>javax.servlet.jsp</groupId>

      <artifactId>javax.servlet.jsp-api</artifactId>

      <version>2.2.</version>

      <scope>provided</scope>

    </dependency>

  </dependencies>

  <build>

    <finalName>servlet-demo</finalName>

    <plugins>

      <plugin>

        <groupId>org.mortbay.jetty</groupId>

        <artifactId>jetty-maven-plugin</artifactId>

        <version>8.1..v20140903</version>

        <configuration>

          <scanIntervalSeconds></scanIntervalSeconds>

          <connectors>

            <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">

              <port></port>

            </connector>

          </connectors>

          <webAppConfig>

            <contextPath>/</contextPath>

          </webAppConfig>

        </configuration>

      </plugin>

    </plugins>

  </build>

pom.xml

<%-- 下面的内容相当于写在service方法里 --%>

<%

    RequestDispatcher requestDispatcher = request.getRequestDispatcher("myServlet");

    requestDispatcher.include(request, response);

%>

my.jsp

package com.test;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.PrintWriter;

@WebServlet("/myServlet")

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html; charset=utf-8");

        PrintWriter out = response.getWriter();

        out.println("<p>How are you</p>");

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet

4、jsp标准标签请求转发

  <dependencies>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>javax.servlet-api</artifactId>

      <version>3.1.0</version>

      <scope>provided</scope>

    </dependency>

    <dependency>

      <groupId>javax.servlet.jsp</groupId>

      <artifactId>javax.servlet.jsp-api</artifactId>

      <version>2.2.1</version>

      <scope>provided</scope>

    </dependency>

  </dependencies>

  <build>

    <finalName>servlet-demo</finalName>

    <plugins>

      <plugin>

        <groupId>org.mortbay.jetty</groupId>

        <artifactId>jetty-maven-plugin</artifactId>

        <version>8.1.16.v20140903</version>

        <configuration>

          <scanIntervalSeconds>10</scanIntervalSeconds>

          <connectors>

            <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">

              <port>7777</port>

            </connector>

          </connectors>

          <webAppConfig>

            <contextPath>/</contextPath>

          </webAppConfig>

        </configuration>

      </plugin>

    </plugins>

  </build>

pom.xml

<%!

    private String name = "Mike Chang";

%>

<%-- 下面的内容相当于写在service方法里 --%>

<p>I am <%= name %></p>

<jsp:include page="myServlet"/>

my.jsp

package com.test;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.PrintWriter;

@WebServlet("/myServlet")

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html; charset=utf-8");

        PrintWriter out = response.getWriter();

        out.println("<p>How are you</p>");

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet

I am Mike Chang

How are you

输出

5、jsp核心标签库请求转发

  <dependencies>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>javax.servlet-api</artifactId>

      <version>3.1.0</version>

      <scope>provided</scope>

    </dependency>

    <dependency>

      <groupId>javax.servlet.jsp</groupId>

      <artifactId>javax.servlet.jsp-api</artifactId>

      <version>2.2.1</version>

      <scope>provided</scope>

    </dependency>

    <dependency>

      <groupId>javax.servlet</groupId>

      <artifactId>jstl</artifactId>

      <version>1.2</version>

    </dependency>

  </dependencies>

  <build>

    <finalName>servlet-demo</finalName>

    <plugins>

      <plugin>

        <groupId>org.mortbay.jetty</groupId>

        <artifactId>jetty-maven-plugin</artifactId>

        <version>8.1.16.v20140903</version>

        <configuration>

          <scanIntervalSeconds>10</scanIntervalSeconds>

          <connectors>

            <connector implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">

              <port>7777</port>

            </connector>

          </connectors>

          <webAppConfig>

            <contextPath>/</contextPath>

          </webAppConfig>

        </configuration>

      </plugin>

    </plugins>

  </build>

pom.xml

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<%!

    private String name = "Mike";

%>

<%-- 下面的内容相当于写在service方法里 --%>

<p>I am <%= name %></p>

<c:import url="myServlet"/>

my.jsp

package com.test;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.PrintWriter;

@WebServlet("/myServlet")

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html; charset=utf-8");

        PrintWriter out = response.getWriter();

        out.println("<p>How are you</p>");

    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

}

myServlet

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