为什么80%的码农都做不了架构师?>>>
获取 HttpServletRequest 中的请求体
HttpServletRequest#getInputStream() 获取到请求的输入流,从该输入流中可以读取到请求体。不过这个流在被我们的代码 read 过后,之后的代码就会报错,因为流已经被我们读取过了 , 尝试使用 mark() , reset() 也是不行的,会抛出异常。可以通过将 HttpServletRequest 对象包装一层的方式来实现这个功能。
package org.hepeng.commons.http;
import lombok.AllArgsConstructor;
import lombok.Data;
import org.apache.commons.io.IOUtils;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
/**
*
* @author he peng
* @date 2018/9/11
*/
public class BodyCachingHttpServletRequestWrapper extends HttpServletRequestWrapper {
private byte[] body;
private ServletInputStreamWrapper inputStreamWrapper;
public BodyCachingHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
this.body = IOUtils.toByteArray(request.getInputStream());
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(this.body);
this.inputStreamWrapper = new ServletInputStreamWrapper(byteArrayInputStream);
resetInputStream();
}
private void resetInputStream() {
this.inputStreamWrapper.setInputStream(new ByteArrayInputStream(this.body != null ? this.body : new byte[0]));
}
public byte[] getBody() {
return body;
}
@Override
public ServletInputStream getInputStream() throws IOException {
return this.inputStreamWrapper;
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.inputStreamWrapper));
}
@Data
@AllArgsConstructor
private static class ServletInputStreamWrapper extends ServletInputStream {
private InputStream inputStream;
@Override
public boolean isFinished() {
return true;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
@Override
public int read() throws IOException {
return this.inputStream.read();
}
}
}
获取 HttpServletResponse 中的响应体
通过使用 ByteArrayOutputStream 将原 HttpSevletResponse 进行一层包装就可以实现。ByteArrayOutputStream 是将数据写入到它内部的缓冲区中,这样我们就可以获取到这个数据了。
package org.hepeng.commons.http;
import lombok.AllArgsConstructor;
import lombok.Data;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
/**
* @author he peng
* @date 2018/10/1
*/
public class BodyCachingHttpServletResponseWrapper extends HttpServletResponseWrapper {
private ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
private HttpServletResponse response;
public BodyCachingHttpServletResponseWrapper(HttpServletResponse response) {
super(response);
this.response = response;
}
public byte[] getBody() {
return byteArrayOutputStream.toByteArray();
}
@Override
public ServletOutputStream getOutputStream() {
return new ServletOutputStreamWrapper(this.byteArrayOutputStream , this.response);
}
@Override
public PrintWriter getWriter() throws IOException {
return new PrintWriter(new OutputStreamWriter(this.byteArrayOutputStream , this.response.getCharacterEncoding()));
}
@Data
@AllArgsConstructor
private static class ServletOutputStreamWrapper extends ServletOutputStream {
private ByteArrayOutputStream outputStream;
private HttpServletResponse response;
@Override
public boolean isReady() {
return true;
}
@Override
public void setWriteListener(WriteListener listener) {
}
@Override
public void write(int b) throws IOException {
this.outputStream.write(b);
}
@Override
public void flush() throws IOException {
if (! this.response.isCommitted()) {
byte[] body = this.outputStream.toByteArray();
ServletOutputStream outputStream = this.response.getOutputStream();
outputStream.write(body);
outputStream.flush();
}
}
}
}
flush() 函数是必须提供的 ,否则流中的数据无法响应到客户端 , ByteArrayOutputStream 没有实现 flush() 。像 SpringMVC 这类框架会去调用这个响应输出流中的 flush() 函数 ,而且有可能在出现多次调用的情况,多次调用会产生问题使得客户端得到错误的数据,比如这样的 :
{"errorCode":30001,"errorMsg":"用户未认证","token":null,"entity":null}{"errorCode":30001,"errorMsg":"用户未认证","token":null,"entity":null} ,出现这种情况就说明 flush() 被调用了两次。所以需要在这里判断一下 HttpServletResponse#isCommitted() 。
获取请求体、相应体的包装类在 Filter 中的使用
package org.hepeng.commons.http.filter;
import com.tepin.commons.http.BodyCachingHttpServletRequestWrapper;
import com.tepin.commons.http.BodyCachingHttpServletResponseWrapper;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* @author he peng
* @date 2018/10/2
*/
public class DemoFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
BodyCachingHttpServletRequestWrapper requestWrapper =
new BodyCachingHttpServletRequestWrapper((HttpServletRequest) request);
byte[] requestBody = requestWrapper.getBody();
// TODO do something
BodyCachingHttpServletResponseWrapper responseWrapper =
new BodyCachingHttpServletResponseWrapper((HttpServletResponse) response);
chain.doFilter(requestWrapper , responseWrapper);
byte[] responseBody = responseWrapper.getBody();
// TODO do something
}
@Override
public void destroy() {
}
}
转载于:https://my.oschina.net/j4love/blog/2222355
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