tomcat域名跳转

<web-app>
  <servlet>
    <servlet-name>RedirectServlet</servlet-name>
    <servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>RedirectServlet</servlet-name>
    <url-pattern>/old-path/*</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
  </welcome-file-list>
  <error-page>
    <error-code>404</error-code>
    <location>/old-path/</location>
  </error-page>
</web-app>

<error-page>
  <error-code>404</error-code>
  <location>/old-path/</location>
</error-page>

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class RedirectFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化代码
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;

        String requestURI = req.getRequestURI();
        if (requestURI.startsWith("/old-path")) {
            res.sendRedirect("/new-path" + requestURI.substring("/old-path".length()));
        } else {
            chain.doFilter(request, response);
        }
    }

    @Override
    public void destroy() {
        // 销毁代码
    }
}

<filter>
  <filter-name>RedirectFilter</filter-name>
  <filter-class>com.example.RedirectFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>RedirectFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

<error-page>
  <error-code>404</error-code>
  <location>/old-path/</location>
</error-page>

res.sendRedirect("/new-path" + requestURI.substring("/old-path".length()), HttpServletResponse.SC_MOVED_PERMANENTLY);