关于request.getServletPath()返回路径问题的探究

前缀匹配：如 /down/*

1.仅仅一个Servlet情况下：
请求URL：http://127.0.0.1:8080/free/down/xxx/yyy/123.jpg，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet("/down/*")
    public class TestServlet extends HttpServlet
    {
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		String servletPath=request.getServletPath();
    		System.out.println("Servlet得到的servletPath路径："+servletPath);
    	}
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		// TODO Auto-generated method stub
    		doGet(request, response);
    	}
    }

控制台打印：
Servlet得到的servletPath路径：/down

2.仅仅一个Filter情况下：
请求URL：http://127.0.0.1:8080/free/down/xxx/yyy/123.jpg，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    
    @WebFilter("/down/*")
    public class TestFilter implements Filter
    {
    	public void init(FilterConfig fConfig) throws ServletException
    	{
    	}
    	public void destroy()
    	{
    	}
    
    	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
    			throws IOException, ServletException
    	{
    		HttpServletRequest httpReq=(HttpServletRequest)request;
    		String servletPath=httpReq.getServletPath();
    		System.out.println("Filter得到的servletPath路径："+servletPath);
    		chain.doFilter(request, response);
    	}

    }

控制台打印：
Filter得到的servletPath路径：/down/xxx/yyy/123.jpg

3.当Filter和Servlet同时作用时，即Filter和Servlet的url-pattern都为"/down/*"时：
请求URL：http://127.0.0.1:8080/free/down/xxx/yyy/123.jpg，其中/free为ContextPath。

控制台打印：
Filter得到的servletPath路径：/down
Servlet得到的servletPath路径：/down

精确路径：如 /down/123.html

1.仅仅一个Servlet情况下：
请求URL：http://127.0.0.1:8080/free/down/123.html，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet("/down/123.html")
    public class TestServlet extends HttpServlet
    {
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		String servletPath=request.getServletPath();
    		System.out.println("Servlet得到的servletPath路径："+servletPath);
    	}
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		// TODO Auto-generated method stub
    		doGet(request, response);
    	}
    }

控制台打印：
Servlet得到的servletPath路径：/down/123.html

2.仅仅一个Filter情况下：
请求URL：http://127.0.0.1:8080/free/down/123.html，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    
    @WebFilter("/down/123.html")
    public class TestFilter implements Filter
    {
    	public void init(FilterConfig fConfig) throws ServletException
    	{
    	}
    	public void destroy()
    	{
    	}
    
    	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
    			throws IOException, ServletException
    	{
    		HttpServletRequest httpReq=(HttpServletRequest)request;
    		String servletPath=httpReq.getServletPath();
    		System.out.println("Filter得到的servletPath路径："+servletPath);
    		chain.doFilter(request, response);
    	}
    }

控制台打印：
Filter得到的servletPath路径：/down/123.html

3.当Filter和Servlet同时作用时，即Filter和Servlet的url-pattern都为"/down/123.html"时：
请求URL：http://127.0.0.1:8080/free/down/123.html，其中/free为ContextPath。

控制台打印：
Filter得到的servletPath路径：/down/123.html
Servlet得到的servletPath路径：/down/123.html

后缀匹配：如 *.api

1.仅仅一个Servlet情况下：
请求URL：http://127.0.0.1:8080/free/down/xyz.api，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet("*.api")
    public class TestServlet extends HttpServlet
    {
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		String servletPath=request.getServletPath();
    		System.out.println("Servlet得到的servletPath路径："+servletPath);
    	}
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    	{
    		// TODO Auto-generated method stub
    		doGet(request, response);
    	}
    }

控制台打印：
Servlet得到的servletPath路径：/down/xyz.api

2.仅仅一个Filter情况下：
请求URL：http://127.0.0.1:8080/free/down/xyz.api，其中/free为ContextPath。

    package my;
    
    import java.io.IOException;
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    
    @WebFilter("*.api")
    public class TestFilter implements Filter
    {
    	public void init(FilterConfig fConfig) throws ServletException
    	{
    	}
    	public void destroy()
    	{
    	}
    
    	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
    			throws IOException, ServletException
    	{
    		HttpServletRequest httpReq=(HttpServletRequest)request;
    		String servletPath=httpReq.getServletPath();
    		System.out.println("Filter得到的servletPath路径："+servletPath);
    		chain.doFilter(request, response);
    	}
    }

控制台打印：
Filter得到的servletPath路径：/down/xyz.api

3.当Filter和Servlet同时作用时，即Filter和Servlet的url-pattern都为"*.api"时：
请求URL：http://127.0.0.1:8080/free/down/xyz.api，其中/free为ContextPath。

控制台打印：
Filter得到的servletPath路径：/down/xyz.api
Servlet得到的servletPath路径：/down/xyz.api