我尝试了下面的示例来替换servlet响应中的一些内容。
test.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8"></meta>
<link th:href="@{/css/test.css}" rel="stylesheet"></link>
<title>Test</title>
</head>
<body>
<p class="forbiddenClass">Test!</p>
</body>
</html>test.css:
.forbiddenClass {
color: red;
}CharResponseWrapper.java
public class CharResponseWrapper extends HttpServletResponseWrapper {
private final CharArrayWriter output;
public CharResponseWrapper(final HttpServletResponse response) {
super(response);
output = new CharArrayWriter();
}
public String toString() {
return output.toString();
}
public PrintWriter getWriter() {
return new PrintWriter(output);
}
}ClassReplacementFilter.java
@Component
public class ClassReplacementFilter extends GenericFilterBean {
@Override
public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
throws IOException, ServletException {
final CharResponseWrapper wrapper = new CharResponseWrapper((HttpServletResponse) response);
chain.doFilter(request, wrapper);
String content = wrapper.toString();
if (StringUtils.isEmpty(content)) {
System.out.println("content is empty for content type: " + response.getContentType());
} else {
content = content.replaceAll("forbiddenClass", "correctClass");
response.setContentLength(content.getBytes().length);
response.getOutputStream().write(content.getBytes());
}
}
}正如您可能看到的,我希望将字符串forbiddenClass替换为correctClass,但它只适用于html文件。test.css的内容不会更改,并将输出筛选器的以下消息。
content is empty for content type: text/css;charset=UTF-8为什么test.css的内容是空的?
发布于 2016-02-24 20:02:26
为什么test.css的内容是空的?
因为您只捕获了任何写入response.getWriter()的内容,而不是任何写入response.getOutputStream()的内容。
您需要HttpServletResponseWrapper实现,如下面对相关问题:捕获所有应该捕获所有HTML输入内容以进行操作的servlet过滤器,只能间歇地工作。的答案的底部所示。
https://stackoverflow.com/questions/35606343
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