一、前言
javax.servlet.http.HttpServletRequestWrapper 是一个开发者可以继承的类,我们可以重写相应的方法来实现session的自定义以及缓存InputStream,在程序中可以多次获取request body的内容。
二、自定义seesion
import javax.servlet.http.*;public class CustomizeHttpServletRequest extends HttpServletRequestWrapper {public CustomizeHttpServletRequest(HttpServletRequest request) {super(request);this.response = response;}@Overridepublic HttpSession getSession() {//return super.getSession(); // 默认使用的是servlet容器session管理return this.getSession(true);}@Overridepublic HttpSession getSession(boolean create) {Cookie[] cookies = this.getCookies();String sessionId = "";//这里编写自己获取session的逻辑//既然是自定义逻辑,可以从内存中取,也可以从缓存中取。 } }
也许大家都用过shiro的session管理或者spring-session,其实想要自己去实现,也是很简单的。
三、缓存InputStream
自定义工具类 ContentCachingRequestWrapper
import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStreamReader;import javax.servlet.ReadListener; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper;import org.apache.commons.io.IOUtils;public class ContentCachingRequestWrapper extends HttpServletRequestWrapper{private byte[] body;private BufferedReader reader;private ServletInputStream inputStream;public ContentCachingRequestWrapper(HttpServletRequest request) throws IOException{super(request);body = IOUtils.toByteArray(request.getInputStream());inputStream = new RequestCachingInputStream(body);}public byte[] getBody() {return body;}@Overridepublic ServletInputStream getInputStream() throws IOException {if (inputStream != null) { return inputStream;}return super.getInputStream();}@Overridepublic BufferedReader getReader() throws IOException {if (reader == null) {reader = new BufferedReader(new InputStreamReader(inputStream, getCharacterEncoding()));}return reader;}private static class RequestCachingInputStream extends ServletInputStream {private final ByteArrayInputStream inputStream;public RequestCachingInputStream(byte[] bytes) {inputStream = new ByteArrayInputStream(bytes);}@Overridepublic int read() throws IOException {return inputStream.read();}@Overridepublic boolean isFinished() {return inputStream.available() == 0;}@Overridepublic boolean isReady() {return true;}@Overridepublic void setReadListener(ReadListener readlistener) {}}}
spring工具类 ContentCachingRequestWrapper
package org.springframework.web.util;import java.io.BufferedReader; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.net.URLEncoder; import java.util.Arrays; import java.util.Enumeration; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import org.springframework.http.HttpMethod;public class ContentCachingRequestWrapper extends HttpServletRequestWrapper {private static final String FORM_CONTENT_TYPE = "application/x-www-form-urlencoded";private final ByteArrayOutputStream cachedContent;private ServletInputStream inputStream;private BufferedReader reader;/*** Create a new ContentCachingRequestWrapper for the given servlet request.* @param request the original servlet request*/public ContentCachingRequestWrapper(HttpServletRequest request) {super(request);int contentLength = request.getContentLength();this.cachedContent = new ByteArrayOutputStream(contentLength >= 0 ? contentLength : 1024);}@Overridepublic ServletInputStream getInputStream() throws IOException {if (this.inputStream == null) {this.inputStream = new ContentCachingInputStream(getRequest().getInputStream());}return this.inputStream;}@Overridepublic String getCharacterEncoding() {String enc = super.getCharacterEncoding();return (enc != null ? enc : WebUtils.DEFAULT_CHARACTER_ENCODING);}@Overridepublic BufferedReader getReader() throws IOException {if (this.reader == null) {this.reader = new BufferedReader(new InputStreamReader(getInputStream(), getCharacterEncoding()));}return this.reader;}@Overridepublic String getParameter(String name) {if (this.cachedContent.size() == 0 && isFormPost()) {writeRequestParametersToCachedContent();}return super.getParameter(name);}@Overridepublic Map<String, String[]> getParameterMap() {if (this.cachedContent.size() == 0 && isFormPost()) {writeRequestParametersToCachedContent();}return super.getParameterMap();}@Overridepublic Enumeration<String> getParameterNames() {if (this.cachedContent.size() == 0 && isFormPost()) {writeRequestParametersToCachedContent();}return super.getParameterNames();}@Overridepublic String[] getParameterValues(String name) {if (this.cachedContent.size() == 0 && isFormPost()) {writeRequestParametersToCachedContent();}return super.getParameterValues(name);}private boolean isFormPost() {String contentType = getContentType();return (contentType != null && contentType.contains(FORM_CONTENT_TYPE) &&HttpMethod.POST.matches(getMethod()));}private void writeRequestParametersToCachedContent() {try {if (this.cachedContent.size() == 0) {String requestEncoding = getCharacterEncoding();Map<String, String[]> form = super.getParameterMap();for (Iterator<String> nameIterator = form.keySet().iterator(); nameIterator.hasNext(); ) {String name = nameIterator.next();List<String> values = Arrays.asList(form.get(name));for (Iterator<String> valueIterator = values.iterator(); valueIterator.hasNext(); ) {String value = valueIterator.next();this.cachedContent.write(URLEncoder.encode(name, requestEncoding).getBytes());if (value != null) {this.cachedContent.write('=');this.cachedContent.write(URLEncoder.encode(value, requestEncoding).getBytes());if (valueIterator.hasNext()) {this.cachedContent.write('&');}}}if (nameIterator.hasNext()) {this.cachedContent.write('&');}}}}catch (IOException ex) {throw new IllegalStateException("Failed to write request parameters to cached content", ex);}}/*** Return the cached request content as a byte array.*/public byte[] getContentAsByteArray() {return this.cachedContent.toByteArray();}private class ContentCachingInputStream extends ServletInputStream {private final ServletInputStream is;public ContentCachingInputStream(ServletInputStream is) {this.is = is;}@Overridepublic int read() throws IOException {int ch = this.is.read();if (ch != -1) {cachedContent.write(ch);}return ch;}@Overridepublic boolean isFinished() {return is.available() == 0;}@Overridepublic boolean isReady() {return true;}@Overridepublic void setReadListener(ReadListener readlistener) {}}}
获取InputStream
1、使用自定义工具类的时候调用方法 getBody
2、使用spring工具类的时候调用方法 getContentAsByteArray
打印request中的所有请求信息,详细代码如下。
private void printRequest(HttpServletRequest request) {String body = StringUtils.EMPTY;try {if (request instanceof ContentCachingRequestWrapper) {body = new String(((ContentCachingRequestWrapper) request).getContentAsByteArray(), "UTF-8");LOGGER.info("Request-Inputstream: " + body);}} catch (IOException e) {LOGGER.error("printRequest 获取body异常...", e);}JSONObject requestJ = new JSONObject();JSONObject headers = new JSONObject();Collections.list(request.getHeaderNames()).stream().forEach(name -> headers.put(name, request.getHeader(name)));requestJ.put("headers", headers);requestJ.put("parameters", request.getParameterMap());requestJ.put("body", body);requestJ.put("remote-user", request.getRemoteUser());requestJ.put("remote-addr", request.getRemoteAddr());requestJ.put("remote-host", request.getRemoteHost());requestJ.put("remote-port", request.getRemotePort());requestJ.put("uri", request.getRequestURI());requestJ.put("url", request.getRequestURL());requestJ.put("servlet-path", request.getServletPath());requestJ.put("method", request.getMethod());requestJ.put("query", request.getQueryString());requestJ.put("path-info", request.getPathInfo());requestJ.put("context-path", request.getContextPath());LOGGER.info("Request-Info: " + JSON.toJSONString(requestJ, SerializerFeature.PrettyFormat)); }
request中的所有请求信息示例
Request-Inputstream: {"timestamp":1539155028668,"appId":"cmos10086e36ipz2otyy8gfqh","nonce":691879,"telephone":"18736085778","signature":"226e734a49d513b3b1e364a06fc6f4eb5e2c425c6446ce6a7a950f1d8d6af06c" }Request-Info: {"headers":{"x-real-ip":"211.138.20.171","content-length":"183","content-encoding":"UTF-8","host":"221.176.66.251","connection":"close","content-type":"application/json","accept-encoding":"gzip,deflate","user-agent":"Apache-HttpClient/4.5.3 (Java/1.7.0_76)"},"remote-host":"172.17.20.92","method":"POST","body":"{\"timestamp\":1539155028668,\"appId\":\"cmos10086e36ipz2otyy8gfqh\",\"nonce\":691879,\"telephone\":\"18736085778\",\"signature\":\"226e734a49d513b3b1e364a06fc6f4eb5e2c425c6446ce6a7a950f1d8d6af06c\"}","uri":"/wmhopenapi/hevb-api/total","url":"http://221.176.66.251/wmhopenapi/hevb-api/total","servlet-path":"/hevb-api/total","remote-addr":"172.17.20.92","context-path":"/wmhopenapi","remote-port":49174,"parameters":{} }
四、在Filter中替换掉默认的Request
import org.springframework.boot.web.servlet.FilterRegistrationBean; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.util.ContentCachingRequestWrapper;import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import java.io.IOException;@Configuration public class FilterConfig {@Beanpublic FilterRegistrationBean wmhFilterRegistration() {FilterRegistrationBean registration = new FilterRegistrationBean();registration.setFilter(new WmhFilter());registration.addUrlPatterns("/*");registration.setName("MyFilter");registration.setOrder(1);return registration;}private static class WmhFilter implements Filter {@Overridepublic void init(javax.servlet.FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {chain.doFilter(new ContentCachingRequestWrapper((HttpServletRequest) request), response);}@Overridepublic void destroy() {}} }
五、使用场景
个人认为,在做权限管理、用户管理、登录等场景,尤其是多系统的情况下,常常需要借助第三方的工具比如shiro,spring-session,完成权限、角色、用户、登录的管理逻辑。之前我自己也尝试过使用spring-session+redis缓存实现共享session和单点登录的逻辑。如果时间充分的话,完全可以自己去写一套session管理的工具,并应用到项目中去。
最近在配合其他组的同时联调接口的时候,遇到了这样的一种情况:他说request body的内容是按照我的协议来的,我后端的实现是通过@RequestBody注解拿到的一个java 对象,有一个字段值为null,很是诡异。于是我俩就纠结是谁的问题,我说他参数传的不对,他说我字段定义不对并让我打印一下Request InputStream,于是就开始寻找解决方案。我们都知道Input Sream只能获取一次,再次获取一定会抛出异常。通过寻找HttpServletRequest的子类,发现了spring提供了这样一个缓存Input Stream内容的工具类,问题迎刃而解。