用 Servlet 過濾器解決 JSP 中文亂碼問題

全站統一編碼處理，避免每個 JSP 重複設定。

EncodingFilter.java

public class Encoding implements Filter {
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    req.setCharacterEncoding("GBK");
    chain.doFilter(req, res);
  }
  public void init(FilterConfig cfg) {}
  public void destroy() {}
}

web.xml 配置

<filter>
  <filter-name>encoding</filter-name>
  <filter-class>com.encoding.Encoding</filter-class>
</filter>
<filter-mapping>
  <filter-name>encoding</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

所有請求經過過濾器強制設定編碼，徹底解決 GET/POST 中文亂碼。