17-request路径区分

1. request 中的路径分类

项目名称：/demo (IDEA中修改了当前Tomcat配置项目访问根目录为 /demo)
当前资源：/path
访问路径：http://127.0.0.1:8080/demo/path

1.1 资源路径

• request.getServletPath();

  毋庸置疑为 Servlet 资源路径： /path

1.2 部署路径

• request.getRealPath(“index.jsp”); // 过时了
• request.getServletContext().getRealPath(“index.jsp”);
• request.getSession().getServletContext().getRealPath(“index.jsp”);

  getRealPath(String path) 统一是部署路径：
  磁盘路径\out\artifacts\demo_job_war_exploded\index.jsp
  应用：

  1. 上传文件路径：xxx.getRealPath(“uploadDir”) + File.separator + uploadFilename

1.3 项目路径

• this.getServletContext().getContextPath();
• request.getContextPath();
• request.getServletContext().getContextPath();
• request.getSession().getServletContext().getContextPath();

  getContextPath() 统一是项目路径： /demo
  应用：

  1. 重定向路径： request.getContextPath() + servletPath或htmlPath
  2. 下载文件路径：request.getContextPath() + File.separator + “uploadDir” + File.separator + uploadFilename

1.4 URI 与 URL

• request.getRequestURI();
• request.getRequestURL();

  访问http://127.0.0.1:8080/demo/path 验证结果：

  1. URI 路径为：/demo/path (当前 Servlet 在项目的绝对路径)
  2. URL 路径为：http://127.0.0.1:8080/demo/path (当前 Servlet 在项目中带协议和地址端口的绝对路径)

  总结：URL = 协议 + ip:port + URI

2. 源码验证 + 输出截图

@WebServlet(name = "TestPathServlet", urlPatterns = "/path")
public class TestPathServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        /* 项目名称：/demo 当前资源：/path */

        // 毋庸置疑 ServletPath 为 "/path"
        String servletPath = request.getServletPath();

        // getRealPath(String path) 统一是部署路径: "磁盘路径\out\artifacts\demo_job_war_exploded\index.jsp"
        // 应用：
        // 1. 上传文件路径：xxx.getRealPath("uploadDir") + File.separator + uploadFilename
        String realPath1 = request.getRealPath("index.jsp");
        String realPath2 = request.getServletContext().getRealPath("index.jsp");
        String realPath3 = request.getSession().getServletContext().getRealPath("index.jsp");

        // getContextPath() 统一是项目路径： "/demo"
        // 应用：
        // 1. 重定向路径： request.getContextPath() + servletPath或htmlPath
        // 2. 下载文件路径：request.getContextPath() + File.separator + "uploadDir" + File.separator + uploadFilename
        String contextPath = this.getServletContext().getContextPath();
        String contextPath1 = request.getContextPath();
        String contextPath2 = request.getServletContext().getContextPath();
        String contextPath3 = request.getSession().getServletContext().getContextPath();

        // 访问：http://127.0.0.1:8080/demo/path得出的结果
        String remoteUser = request.getRemoteUser(); // null
        int localPort = request.getLocalPort(); // 8080
        String localAddr = request.getLocalAddr(); // 127.0.0.1
        String remoteAddr = request.getRemoteAddr(); // 127.0.0.1
        int remotePort = request.getRemotePort(); // 8080
        // /demo/path (当前 Servlet 在项目的绝对路径)
        String requestURI = request.getRequestURI();
        // http://127.0.0.1:8080/demo/path (当前 Servlet 在项目中带协议和地址端口的绝对路径)
        StringBuffer requestURL = request.getRequestURL();
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

输出截图：