post请求体内容无法重复获取
为什么会无法重复读取呢？
以tomcat为例，在进行请求体读取时实际底层调用的是org.apache.catalina.connector.Request的getInputStream()方法，而该方法返回的是CoyoteInputStream输入流
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| public ServletInputStream getInputStream() throws IOException {
if (usingReader) {
throw new IllegalStateException(sm.getString("coyoteRequest.getInputStream.ise"));
}
usingInputStream = true;
if (inputStream == null) {
inputStream = new CoyoteInputStream(inputBuffer);
}
return inputStream;
}
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在使用CoyoteInputStream进行读取时
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| public int read(byte[] b, int off, int len) throws IOException {
if (closed) {
throw new IOException(sm.getString("inputBuffer.streamClosed"));
}
if (checkByteBufferEof()) {
return -1;
}
int n = Math.min(len, bb.remaining());
bb.get(b, off, n);
return n;
}
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而流读取完毕都会进行close，这个流close之后，close状态就置为了true，所以导致流无法进行二次读取
那么如何解决呢？将tomcat的Request类进行重新实现吗？代价太大了，sun公司当初在设计的时候就已经提供了解决方法，对于请求和响应，sun公司提供了包装类，可以HttpServletRequestWrapper类包装原始的request对象，实现了HttpServletRequest接口的所有方法，内部调用了所包装的request对象的对应方法；相应的也有HttpServletResponseWrapper类来包装原始的response对象继承HttpServletRequestWrapper来进行方法重写，可以使用HttpServletResponseWrapper和HttpServletRequestWrapper来进行定制响应和请求
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| public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
private byte[] body;
private HttpServletRequest orgRequest;
public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
this.orgRequest = request;
body = HttpHelper.getBody(request);
}
public HttpServletRequest getOrgRequest() {
return this.orgRequest;
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body);
return new ServletInputStream() {
@Override
public int read() throws IOException {
return bais.read();
}
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
};
}
}
|