简介
在项目中，有两个场景会用到从 RequestBody 中读取内容。
-
打印请求日志
-
提供 Api 接口，在 Api 方法执行之前，从 RequestBody 中读取参数进行验签，验签通过后再执行 Api 方法的具体逻辑
这时就需要对 RequestBoy 进行重复读取。要实现对 RequestBody 进行重复读取的思路如下：
-
继承 HttpServletRequestWrapper 包装类，读取 RequestBody 的内容，然后缓存到 byte[] 数组 中；
-
增加过滤器，将包装类加入过滤器链中；
由于采用采用application/json传输参数时，HttpServletRequest只能读取一次 body 中的内容。因为是读的字节流，读完就没了，因此需要需要做特殊处理。为实现述多次读取 Request 中的 Body 内容，需继承 HttpServletRequestWrapper 类，读取 Body 的内容，然后缓存到 byte[] 中；这样就可以实现多次读取 Body 的内容了。
package com.olive.request;
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.*;
public class RequestWrapper extends HttpServletRequestWrapper {
//参数字节数组
private byte[] requestBody;
//Http请求对象
private HttpServletRequest request;
public RequestWrapper(HttpServletRequest request) throws IOException {
super(request);
this.request = request;
}
@Override
public ServletInputStream getInputStream() throws IOException {
/**
* 每次调用此方法时将数据流中的数据读取出来，然后再回填到InputStream之中
* 解决通过@RequestBody和@RequestParam（POST方式）读取一次后控制器拿不到参数问题
*/
if (null == this.requestBody) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
IOUtils.copy(request.getInputStream(), baos);
this.requestBody = baos.toByteArray();
}
final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);
return new ServletInputStream() {
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener listener) {
}
@Override
public int read() {
return bais.read();
}
};
}
public byte[] getRequestBody() {
return requestBody;
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.getInputStream()));
}
}
增加过滤器，转换Request为自定义Request
package com.olive.filter;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
public class RequestBodyReaderFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
try {
ServletRequest requestWrapper = null;
if (request instanceof HttpServletRequest) {
requestWrapper = new RequestWrapper((HttpServletRequest) request);
}
if (requestWrapper == null) {
chain.doFilter(request, response);
} else {
chain.doFilter(requestWrapper, response);
}
} catch (IOException e) {
e.printStackTrace();
} catch (ServletException e) {
e.printStackTrace();
}
}
@Override
public void destroy() {
}
}
注册Filter
package com.olive.config;
import java.util.ArrayList;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.olive.filter.RequestBodyReaderFilter
@Configuration
public class WebConfig {
@Bean
public FilterRegistrationBean fequestBodyReaderFilter() {
FilterRegistrationBean registrationBean = new FilterRegistrationBean<>();
RequestBodyReaderFilter filter = new RequestBodyReaderFilter();
registrationBean.setFilter(filter);
ArrayList urls = new ArrayList<>();
urls.add("/*");//配置过滤规则
registrationBean.setUrlPatterns(urls);
registrationBean.setOrder(3);
return registrationBean;
}
}
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