Springmvc JSP静态化处理 | 不需要第三方Jar 不需要任何模板化技术

最近想接了一个活，需求是采集多方网站，然后导入到自己库中。
CMS+爬虫。考虑到CMS期初打算用 织梦做一个前台，java做数据来着，结果想了想还是自己写一个吧。

尝试了下Freemarker，但是都有点缺点就是 标签库不够我用，不能定义全局变量。个人习惯想找一个不需要任何框架，我就一个modelandview对象你就生成html就行。找了很多 ぜんぜん 不好使。所以考虑自己写一个吧，参考了国外大神的回答：https://stackoverflow.com/questions/8933054/how-to-read-and-copy-the-http-servlet-response-output-stream-content-for-logging

首先，Springmvc 它自己是不给我们返回响应的，这一点搞得人很纠结，所以要重写方法。

You need to create a Filter wherein you wrap the ServletResponse argument with a custom HttpServletResponseWrapper implementation wherein you override the getOutputStream() and getWriter() to return a custom ServletOutputStream implementation wherein you copy the written byte(s) in the base abstract OutputStream#write(int b) method. Then, you pass the wrapped custom HttpServletResponseWrapper to the FilterChain#doFilter() call instead and finally you should be able to get the copied response after the the call.
上面是原话。就是重写 response 和 ServletOutputStream 。然后建立一个过滤器即可。

过滤器：

@WebFilter("/*")
public class ResponseLogger implements Filter {

@Override
public void init(FilterConfig config) throws ServletException {
// NOOP.
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
if (response.getCharacterEncoding() == null) {
response.setCharacterEncoding("UTF-8"); // Or whatever default. UTF-8 is good for World Domination.
}

HttpServletResponseCopier responseCopier = new HttpServletResponseCopier((HttpServletResponse) response);

try {
chain.doFilter(request, responseCopier);
responseCopier.flushBuffer();
} finally {
byte[] copy = responseCopier.getCopy();
}
}

@Override
public void destroy() {
// NOOP.
}

}

在过滤器中使用“new String(copy, response.getCharacterEncoding())” 获取返回的响应内容。然后写一个写入到文件的方法，就可以生成html咯。不过速度挺一般的。
大家可以在后台单独写一个方法，然后定义为生成html的方法，然后首页列表页直接修改为静态页面的地址即可。因为这个生成html要走过滤器，大家也可以自行改进，然后做成调用的方法来用就比较好使。

重写的Response

public class HttpServletResponseCopier extends HttpServletResponseWrapper {

private ServletOutputStream outputStream;
private PrintWriter writer;
private ServletOutputStreamCopier copier;

public HttpServletResponseCopier(HttpServletResponse response) throws IOException {
super(response);
}

@Override
public ServletOutputStream getOutputStream() throws IOException {
if (writer != null) {
throw new IllegalStateException("getWriter() has already been called on this response.");
}

if (outputStream == null) {
outputStream = getResponse().getOutputStream();
copier = new ServletOutputStreamCopier(outputStream);
}

return copier;
}

@Override
public PrintWriter getWriter() throws IOException {
if (outputStream != null) {
throw new IllegalStateException("getOutputStream() has already been called on this response.");
}

if (writer == null) {
copier = new ServletOutputStreamCopier(getResponse().getOutputStream());
writer = new PrintWriter(new OutputStreamWriter(copier, getResponse().getCharacterEncoding()), true);
}

return writer;
}

@Override
public void flushBuffer() throws IOException {
if (writer != null) {
writer.flush();
} else if (outputStream != null) {
copier.flush();
}
}

public byte[] getCopy() {
if (copier != null) {
return copier.getCopy();
} else {
return new byte[0];
}
}

}

重写的ServletOutputStream

public class ServletOutputStreamCopier extends ServletOutputStream {

private OutputStream outputStream;
private ByteArrayOutputStream copy;

public ServletOutputStreamCopier(OutputStream outputStream) {
this.outputStream = outputStream;
this.copy = new ByteArrayOutputStream(1024);
}

@Override
public void write(int b) throws IOException {
outputStream.write(b);
copy.write(b);
}

public byte[] getCopy() {
return copy.toByteArray();
}

}