如何在春季缩小动态HTML响应？

html minify java spring spring-boot

2022-09-01 21:16:15

按照Google的pagespeed建议，我希望缩小我的Spring应用程序的HTML响应。我不是指GZip，我的意思是在HTML被发送到网络上之前从HTML中删除注释和空格。

我想动态地执行此操作，而不是在我的模板中执行此操作。我的模板包含许多有用的注释，但不应成为响应的一部分。

以下是我的控制器;

@Controller
public class IndexController {

    @GetMapping("/")
    public ModelAndView index() {
        Data data = ....
        return new ModelAndView("index", data);
    }
}

答案 1

我设法通过在Spring中添加一个使用com.googlecode.htmlcompressor的javax.servlet.Filter组件来做到这一点。

首先Filter;

@Component
public class HtmlFilter implements Filter {
    protected FilterConfig config;

    public void init(FilterConfig config) throws ServletException {
        this.config = config;
    }

    public void destroy() {
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws ServletException, IOException {
        ServletResponse newResponse = response;

        if (request instanceof HttpServletRequest) {
            newResponse = new CharResponseWrapper((HttpServletResponse) response);
        }

        chain.doFilter(request, newResponse);

        if (newResponse instanceof CharResponseWrapper) {
            String text = newResponse.toString();
            if (text != null) {
                HtmlCompressor htmlCompressor = new HtmlCompressor();
                response.getWriter().write(htmlCompressor.compress(text));
            }
        }
    }
}

和相关CharResponseWrapper;

class CharResponseWrapper extends HttpServletResponseWrapper {
    protected CharArrayWriter charWriter;
    protected PrintWriter writer;
    protected boolean getOutputStreamCalled;
    protected boolean getWriterCalled;

    public CharResponseWrapper(HttpServletResponse response) {
        super(response);

        charWriter = new CharArrayWriter();
    }

    public ServletOutputStream getOutputStream() throws IOException {
        if (getWriterCalled) {
            throw new IllegalStateException("getWriter already called");
        }

        getOutputStreamCalled = true;
        return super.getOutputStream();
    }

    public PrintWriter getWriter() throws IOException {
        if (writer != null) {
            return writer;
        }
        if (getOutputStreamCalled) {
            throw new IllegalStateException("getOutputStream already called");
        }
        getWriterCalled = true;
        writer = new PrintWriter(charWriter);
        return writer;
    }

    public String toString() {
        String s = null;

        if (writer != null) {
            s = charWriter.toString();
        }
        return s;
    }
}

效果很好。转换一个html这么丑陋;

<!DOCTYPE HTML>
<html>
<head>
    <title>
        A Simple
        <!--        Test-->
        HTML Document
        <!--        Test-->

    </title>



</head>
<body>
                 <p>This is a very simple HTML document</p>


                 <!--        Test-->



<p>It only has two<!--        Test--> paragraphs</p>

                 <!--        Test-->

</body>
</html>

进入这个;

<!DOCTYPE HTML> <html> <head> <title> A Simple HTML Document </title> </head> <body> <p>This is a very simple HTML document</p> <p>It only has two paragraphs</p> </body> </html>

答案 2