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本篇内容介绍了“怎么解决在controller中无法二次读取的问题”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
拦截器中读取request参数,在controller中无法二次读取
新建类
添加过滤器
使用拦截器时,controller中不能再次获取body中的参数
解决办法
1、获取body信息
2、重新写入
3、注册过滤器
package com.ouyeelbuy.mc.common.base; import javax.servlet.ReadListener; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import java.io.*; /** * @author robin.zhang * @date $ * @description 解决在request的数据流只能读取一次的问题 */ public class RequestWrapper extends HttpServletRequestWrapper { private final String body; public RequestWrapper(HttpServletRequest request) { super(request); StringBuilder stringBuilder = new StringBuilder(); BufferedReader bufferedReader = null; InputStream inputStream = null; try { inputStream = request.getInputStream(); if (inputStream != null) { bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); char[] charBuffer = new char[128]; int bytesRead = -1; while ((bytesRead = bufferedReader.read(charBuffer)) > 0) { stringBuilder.append(charBuffer, 0, bytesRead); } } else { stringBuilder.append(""); } } catch (IOException ex) { } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (bufferedReader != null) { try { bufferedReader.close(); } catch (IOException e) { e.printStackTrace(); } } } body = stringBuilder.toString(); } @Override public ServletInputStream getInputStream() throws IOException { final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes()); ServletInputStream servletInputStream = new ServletInputStream() { @Override public boolean isFinished() { return false; } @Override public boolean isReady() { return false; } @Override public void setReadListener(ReadListener readListener) { } @Override public int read() throws IOException { return byteArrayInputStream.read(); } }; return servletInputStream; } @Override public BufferedReader getReader() throws IOException { return new BufferedReader(new InputStreamReader(this.getInputStream())); } public String getBody() { return this.body; } }
package com.ouyeelbuy.mc.common.filter; import com.ouyeelbuy.mc.common.base.RequestWrapper; import org.springframework.stereotype.Component; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import java.io.IOException; /** * @author robin.zhang * @date $ * @description 解决request数据流只能读取一次的问题 */ @Component public class RequestFilter implements Filter{ @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { ServletRequest requestWrapper = null; if(servletRequest instanceof HttpServletRequest) { requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest); } if(requestWrapper == null) { filterChain.doFilter(servletRequest, servletResponse); } else { filterChain.doFilter(requestWrapper, servletResponse); } } @Override public void destroy() { } }
然后注册这个过滤器到spring容器中,问题解决!
报错信息:从报错信息可以看出,io流已经关闭。这是由于拦截器读取了body中的参数信息,导致controller不能再次读取。
I/O error while reading input message; nested exception is java.io.IOException: Stream closed
在拦截器读取到body信息后,再次将内容写入
import javax.servlet.ReadListener; import javax.servlet.ServletInputStream; import javax.servlet.ServletRequest; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import java.io.*; import java.nio.charset.Charset; /** * 保存流 */ public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper { private final byte[] body; public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) { super(request); String sessionStream = getBodyString(request); body = sessionStream.getBytes(Charset.forName("UTF-8")); } /** * 获取请求Body * * @param request * @return */ public String getBodyString(final ServletRequest request) { StringBuilder sb = new StringBuilder(); InputStream inputStream = null; BufferedReader reader = null; try { inputStream = cloneInputStream(request.getInputStream()); reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8"))); String line = ""; while ((line = reader.readLine()) != null) { sb.append(line); } } catch (IOException e) { e.printStackTrace(); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } } return sb.toString(); } /** * Description: 复制输入流</br> * * @param inputStream * @return</br> */ public InputStream cloneInputStream(ServletInputStream inputStream) { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len; try { while ((len = inputStream.read(buffer)) > -1) { byteArrayOutputStream.write(buffer, 0, len); } byteArrayOutputStream.flush(); } catch (IOException e) { e.printStackTrace(); } InputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray()); return byteArrayInputStream; } @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) { } }; } }
import org.springframework.core.annotation.Order; import javax.servlet.*; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; import java.io.IOException; // 表示执行过滤顺序,值越小,越先执行 @Order(1) // 配置需要过滤的地址 @WebFilter(filterName = "bodyReaderFilter", urlPatterns = "/*") public class BodyReaderFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { // System.out.println("--------------过滤器初始化------------"); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { // System.out.println("--------------执行过滤操作------------"); // 防止流读取一次后就没有了, 所以需要将流继续写出去 HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest; ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper(httpServletRequest); filterChain.doFilter(requestWrapper, servletResponse); } @Override public void destroy() { // System.out.println("--------------过滤器销毁------------"); } }
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.ServletComponentScan; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.openfeign.EnableFeignClients; @SpringBootApplication @EnableFeignClients @EnableDiscoveryClient // 注册过滤器注解 @ServletComponentScan public class WebPlatformApplication { public static void main(String[] args) { SpringApplication.run(WebPlatformApplication.class); } }
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