Urlparrern configuration

urlParrern To configure

Previously, we used annotations to configure this access path , Only one access path is set . In fact, you can also configure multiple access paths . Just like this. .

@WebServlet(urlPatterns = {"/demo7","/demo07"})

In fact, our configuration is a path matching rule or an item matching access rule .

Next we introduce several matching rules
1: Exactly match
What we wrote in the notes , In the future, we need to access the project through this complete path .
eg:

@WebServlet("/jgdabc/666")

2： Directory matching
eg:

/@WebServlet(urlPatterns = "/user/*")  Directory matching 

When we visit in the future, we need to input user, Then you can follow any path .

3： Extension matching

@WebServlet("*.do") 

Any path can be added to the front when visiting in the future , But you need to add do Extension .

4： Any match

//@WebServlet("/")//@WebServlet("/*")

Arbitrary matching is not recommended

1. When... In our project Servlet Configured with “/”, Will overwrite tomcat Medium DefaultServlet, When other url-pattern When they don't match, they will take this Servlet
2. When our project is configured with "/*", Means matching any access path
3. DefaultServlet Is used to handle static resources , If the "/" Will overwrite the default , It will cause the user-defined instead of the default when requesting static resources Servlet class , As a result, static resources cannot be accessed

The test case

package jgd;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("/jgdabc/666")// Multiple access paths can be configured , This is an exact match //@WebServlet(urlPatterns = {"/demo7","/demo07"})//@WebServlet(urlPatterns = "/user/*")  Directory matching // When both exact matching and directory matching are satisfied , Precise matching has higher priority //@WebServlet("*.do")  Extension matching // Any match // /*  Has a higher priority than ///@WebServlet("/")//@WebServlet("/*")public class ServletDemo7 extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        System.out.println("demo7get...");    }    @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// super.doPost(req, resp);    }}