一、服务器内部转发以及客户端重定向

? ?1.1?服务器内部转发

? ? ? request.getRequestDispatcher("...").forward(request,response);
? ? ? - 一次请求响应的过程，对于客户端而言，内部经过了多少次转发，客户端是不知道的
? ? ? - 地址栏没有变化

测试代码：

public class Test01 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("test01...");
        //服务器会内部自动转发到test2
        request.getRequestDispatcher("test2").forward(request,response);
    }
}

public class Test02 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("test02");
    }
}

?web.xml配置

    <servlet>
    <servlet-name>Test01</servlet-name>
    <servlet-class>com.cjc.servlets.Test01</servlet-class>
</servlet>
    <servlet-mapping>
        <servlet-name>Test01</servlet-name>
        <url-pattern>/test1</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>Test02</servlet-name>
        <servlet-class>com.cjc.servlets.Test02</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Test02</servlet-name>
        <url-pattern>/test2</url-pattern>
    </servlet-mapping>

1.2客户端重定向

? ? ? response.sendRedirect("....");
? ? ? - 两次请求响应的过程。客户端肯定知道请求URL有变化
? ? ? - 地址栏有变化

public class Test01 extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("test01...");
        //客户端重定向
        response.sendRedirect("test2");
    }
}