如何在Groovy中實現抽象Java類？

Question

我正在嘗試從Spring的教程之一用Groovy編寫一些Spring代碼。 當我在Groovy中編寫以下代碼時：

爪哇

@Component
public class SimpleCORSFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        chain.doFilter(req, res);
    }

    public void init(FilterConfig filterConfig) {}

    public void destroy() {}

}

Groovy

@Component
class SimpleCORSFilter implements Filter {

    void doFilter(ServletRequest req, ServletResponse, FilterChain chain)
            throws IOException, ServletException {
        HttpServletResponse response = res as HttpServletResponse
        response.setHeader("Access-Control-Allow-Origin", "*")
        chain.doFilter(req, res)
    }

    void init (FilterConfig filterConfig) {}
    void destroy() {}
}

我收到以下錯誤

Can't have an abstract method in a non-abstract class. The class 'com.myproject.main.SimpleCORSFilter' must be declared abstract or the method 'void doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)' must be implemented.
 @ line X, column Y.
   @Component
   ^

題

我已經實現了抽象的doFilter方法。 為什么無效？

我怎樣才能解決這個問題？

Answer 1

您在這里有語法錯誤

void doFilter(ServletRequest req, ServletResponse, FilterChain chain)

應該

void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)