Tomcat&Servlet（5）

package com.itheima.web;  
  
import javax.servlet.ServletRequest;  
import javax.servlet.ServletResponse;  
import javax.servlet.annotation.WebServlet;  
  
/**  
* urlPattern: 一个Servlet可以配置多个访问路径  
*/  
@WebServlet(urlPatterns = {"/demo7","/demo8"})  
public class ServletDemo7 extends MyHttpServlet {  
  
    @Override  
    protected void doGet(ServletRequest req, ServletResponse res) {  
          
        System.out.println("demo7 get...");  
    }  
    @Override  
    protected void doPost(ServletRequest req, ServletResponse res) {  
    }  
}

/**
 * UrlPattern:
 * * 精确匹配
 */
@WebServlet(urlPatterns = "/user/select")
public class ServletDemo8 extends MyHttpServlet {
    @Override
    protected void doGet(ServletRequest req, ServletResponse res) {
        System.out.println("demo8 get...");
    }
    @Override
    protected void doPost(ServletRequest req, ServletResponse res) {
    }
}

package com.itheima.web;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
/**
 * UrlPattern:
 * * 目录匹配: /user/*
 */
@WebServlet(urlPatterns = "/user/*")
public class ServletDemo9 extends MyHttpServlet {
    @Override
    protected void doGet(ServletRequest req, ServletResponse res) {
        System.out.println("demo9 get...");
    }
    @Override
    protected void doPost(ServletRequest req, ServletResponse res) {
    }
}

package com.itheima.web;  
  
import javax.servlet.ServletRequest;  
import javax.servlet.ServletResponse;  
import javax.servlet.annotation.WebServlet;  
  
/**  
 * UrlPattern:  
 * * 扩展名匹配: *.do  
 */  
@WebServlet(urlPatterns = "*.do")  
public class ServletDemo10 extends MyHttpServlet {  
  
    @Override  
    protected void doGet(ServletRequest req, ServletResponse res) {  
  
        System.out.println("demo10 get...");  
    }  
    @Override  
    protected void doPost(ServletRequest req, ServletResponse res) {  
    }  
}
访问路径`http://localhost:8080/web-demo/任意.do`
注意:
1.  如果路径配置的不是扩展名，那么在路径的前面就必须要加`/`否则会报错
    
![\[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-bdGmm4XG-1686574478597)(h\]](https://ucc.alicdn.com/images/user-upload-01/69a09263070c4bc1bcf6654707afde76.png)
2. 如果路径配置的是`*.do`,那么在*.do的前面不能加`/`,否则会报错
   
![162727a4368245](https://ucc.alicdn.com/images/user-upload-01/img_convert/102a6b370fc32ddcd1f67050d78103b2.png)

package com.itheima.web;  
  
import javax.servlet.ServletRequest;  
import javax.servlet.ServletResponse;  
import javax.servlet.annotation.WebServlet;  
  
/**  
 * UrlPattern:  
 * * 任意匹配： /  
 */  
@WebServlet(urlPatterns = "/")  
public class ServletDemo11 extends MyHttpServlet {  
  
    @Override  
    protected void doGet(ServletRequest req, ServletResponse res) {  
  
        System.out.println("demo11 get...");  
    }  
    @Override  
    protected void doPost(ServletRequest req, ServletResponse res) {  
    }  
}
访问路径`http://localhost:8080/demo-web/任意`
```java
package com.itheima.web;  
  
import javax.servlet.ServletRequest;  
import javax.servlet.ServletResponse;  
import javax.servlet.annotation.WebServlet;  
  
/**  
 * UrlPattern:  
 * * 任意匹配： /*  
 */  
@WebServlet(urlPatterns = "/*")  
public class ServletDemo12 extends MyHttpServlet {  
  
    @Override  
    protected void doGet(ServletRequest req, ServletResponse res) {  
  
        System.out.println("demo12 get...");  
    }  
    @Override  
    protected void doPost(ServletRequest req, ServletResponse res) {  
    }  
}  
访问路径`[http://localhost:8080/demo-web/](http://localhost:8080/demo-web/)任意
注意:`/`和`/*`的区别?
1.  当我们的项目中的Servlet配置了 "/",会覆盖掉tomcat中的**DefaultServlet**,当其他的url-pattern都匹配不上时都会走这个Servlet
    
2.  当我们的项目中配置了`"/*"`,意味着匹配任意访问路径
    
3.  DefaultServlet是用来处理==静态资源==(也就是网页)，如果配置了"/"会把默认的覆盖掉，就会引发请求静态资源的时候没有走默认的而是走了自定义的Servlet类，最终导致静态资源不能被访问
   ![image.png](https://ucc.alicdn.com/images/user-upload-01/img_convert/6cde3436a73b1492f562840f74d0d068.png)

package com.itheima.web;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import java.io.IOException;  
public class ServletDemo3 extends HttpServlet {  
  @Override  
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  
      System.out.println("demo4...");  
  }  
  @Override  
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {  
  }  
}

<!DOCTYPE web-app PUBLIC  
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"  
"http://java.sun.com/dtd/web-app_2_3.dtd" >  
<web-app>  
<display-name>Archetype Created Web Application</display-name>  
<!--  servlet全类名-->  
<servlet>  
  <!-- servlet的名称，名字任意-->
  <servlet-name>demo4</servlet-name>  
   <!--servlet的类全名-->
  <servlet-class>com.itheima.web.ServletDemo3</servlet-class>  
</servlet>  
<!--  servlet访问路径-->  
<servlet-mapping>  
<!-- servlet的名称，要和上面的名称一致-->
  <servlet-name>demo4</servlet-name>  
    <!-- servlet的访问路径--
  <url-pattern>/demo4</url-pattern>  
</servlet-mapping>  
</web-app>