【发布时间】：2019-05-20 21:08:21
【问题描述】：
我正在尝试读取当前响应并尝试用新数据覆盖响应。但目前我无法这样做。我总是以 GetWriter 已被调用的异常结束
这就是我想要做的事情
我想从响应中读取、修改它并在过滤器中写入一个新响应。我无法正常执行此操作，因为该过程由 swagger-springfox 处理。我正在寻找这种方法的原因是有一个 xml 元素 - 它在 APIDOC 中生成以被删除。我知道这是一次性的，可能存在一些配置问题，但是用于扫描和确定问题所在的文件太多。因此，我决定采用这种方法。此链接中提供了更多详细信息 - https://github.com/springfox/springfox/issues/2821
在我打印的字符串中 - 它工作得非常好，但是响应永远不会发送到客户端，因为似乎响应的 getWriter() 要么已经被调用，要么正在关闭。
这是一个示例 JSON 字符串，您可以 - String s = " <Json>{ \"id\": 1, \"itemName\": \"theItem \", \"owner\": { \"id\": 2, \"name\": \"theUser\" }} </Json>";
这是我的过滤器
public class SwaggerFilter extends GenericFilterBean {
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain)
throws IOException, ServletException {
// TODO Auto-generated method stub
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
if (req.getRequestURI().toLowerCase().endsWith("someURL")) {
try {
ResponseWrapper wrapperResponse = new ResponseWrapper(res);
chain.doFilter(req, wrapperResponse);
String responseContent = new String(wrapperResponse.getDataStream());
System.out.println("response obtained:" + responseContent);
try {
List<String> s13 = Stream.of(responseContent).filter((s1) -> s1.contains("<Json>"))
.map((sample) -> Arrays.asList(sample.split(" ")))
.flatMap((listString) -> {
StringBuffer sb = new StringBuffer();
listString.forEach(item -> {
sb.append(item);
});
return Stream.of(sb.toString().trim().replace("<Json>", "").replace("</Json>", ""));
}).collect(Collectors.toList());
s13.forEach(item -> System.out.println("items :" + item));
String s14 = String.join("", s13);
System.out.println("tt" + s14);
PrintWriter writer = wrapperResponse.getWriter();
writer.write(s14);
writer.close();
} catch (Exception e) {
System.out.println(e.getLocalizedMessage());
}
} finally {
}
}
chain.doFilter(req, res);
}
}
这是servlet输出流
public class FilterServletOutputStream extends ServletOutputStream {
ByteArrayOutputStream bos;
public FilterServletOutputStream(OutputStream output) {
bos = (ByteArrayOutputStream) output;
}
@Override
public boolean isReady() {
// TODO Auto-generated method stub
return false;
}
@Override
public void setWriteListener(WriteListener listener) {
// TODO Auto-generated method stub
}
@Override
public void write(int b) throws IOException {
// TODO Auto-generated method stub
bos.write(b);
}
@Override
public void write(byte[] arg0, int arg1, int arg2) throws IOException {
bos.write(arg0, arg1, arg2);
}
@Override
public void write(byte[] arg0) throws IOException {
bos.write(arg0);
}
}
这是响应包装器
public class ResponseWrapper extends HttpServletResponseWrapper {
ByteArrayOutputStream output;
FilterServletOutputStream filterOutput;
public ResponseWrapper(HttpServletResponse response) {
super(response);
output = new ByteArrayOutputStream();
// TODO Auto-generated constructor stub
}
@Override
public ServletOutputStream getOutputStream() {
if (filterOutput == null) {
filterOutput = new FilterServletOutputStream(output);
}
return filterOutput;
}
public byte[] getDataStream() {
return output.toByteArray();
}
}
错误：
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'server.servlet.contextPath' in value "${server.servlet.contextPath}"
at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:172) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:124) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:237) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:211) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.context.support.PropertySourcesPlaceholderConfigurer.lambda$processProperties$0(PropertySourcesPlaceholderConfigurer.java:175) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:834) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1086) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.4.RELEASE.jar:5.0.4.RELEASE]
... 22 common frames omitted
您能否确定问题出在哪里并帮助编写新的响应数据并将其发送过来？
更新： 我已经重写了大部分。这是代码。不知何故，响应文档是空的。我觉得我几乎可以破解它。有人可以在最后帮助我吗？
@Component
@Order(2)
public class DumpFilter implements Filter {
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
throws IOException, ServletException {
// TODO Auto-generated method stub
HttpServletRequest httpRequest = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
ByteArrayPrinter pw = new ByteArrayPrinter();
HttpServletResponse wrappedResp = new HttpServletResponseWrapper(response) {
@Override
public PrintWriter getWriter() {
return pw.getWriter();
}
@Override
public ServletOutputStream getOutputStream() {
return pw.getStream();
}
};
System.out.println("before chaingin");
chain.doFilter(httpRequest, wrappedResp);
byte[] bytes = pw.toByteArray();
String respBody = new String(bytes);
if (respBody.startsWith("<Json>")) {
System.out.println("in if");
List<String> s13 = Stream.of(respBody).filter((s1) -> s1.contains("<Json>"))
.map((sample) -> Arrays.asList(sample.split(" ")))
.flatMap((listString) -> {
StringBuffer sb = new StringBuffer();
listString.forEach(item -> {
sb.append(item);
});
return Stream.of(sb.toString().trim().replace("<Json>", "").replace("</Json>", ""));
}).collect(Collectors.toList());
s13.forEach(item -> {
System.out.println("items in list:" + item);
try {
response.getOutputStream().write(item.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
});
// String s14 = String.join("", s13);
// System.out.println("s14" + s14.getBytes());
// bytes = s14.getBytes();
// response.getOutputStream().write(s14.getBytes());
} else {
response.getOutputStream().write(bytes);
}
System.out.println("RESPONSE -> " + new String(bytes));
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
}
这里是使用的辅助类：
public class ByteArrayPrinter {
private ByteArrayOutputStream baos = new ByteArrayOutputStream();
private PrintWriter pw = new PrintWriter(baos);
private ServletOutputStream sos = new ByteArrayServletStream(baos);
public PrintWriter getWriter() {
return pw;
}
public ServletOutputStream getStream() {
return sos;
}
byte[] toByteArray() {
return baos.toByteArray();
}
}
public class ByteArrayServletStream extends ServletOutputStream {
ByteArrayOutputStream baos;
ByteArrayServletStream(ByteArrayOutputStream baos) {
this.baos = baos;
}
@Override
public void write(int param) throws IOException {
baos.write(param);
}
@Override
public boolean isReady() {
// TODO Auto-generated method stub
return false;
}
@Override
public void setWriteListener(WriteListener listener) {
// TODO Auto-generated method stub
}
}
在调用 v2/api-docs?groupName=XXXXXX 时，我遇到了错误 - 第 1 行第 1 列的错误：文档为空
【问题讨论】：
标签： spring-boot servlet-filters