这篇文章主要介绍“如何解决SpringBoot v2.2以上重复读取Request Body内容”,在日常操作中,相信很多人在如何解决SpringBoot v2.2以上重复读取Request Body内容问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”如何解决SpringBoot v2.2以上重复读取Request Body内容”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
SpringBoot v2.2以上重复读取Request Body内容
一、需求
二、解决方案
三、遇到问题
四、问题排查
解决方案
Springboot读取Request参数的坑
后端拿参数相关
关于流
项目有两个场景会用到从Request的Body中读取内容。
打印请求日志
提供Api接口,在api方法执行前,从Request Body中读取参数进行验签,验签通过后在执行api方法
2.1 自定义RequestWrapper
public class MyRequestWrapper extends HttpServletRequestWrapper {
private final String body;
public MyRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
this.body = RequestReadUtils.read(request);
}
public String getBody() {
return body;
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body.getBytes());
return new ServletInputStream() {
...略
};
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.getInputStream()));
}
}
RequestReadUtils(网上抄的)
private static final int BUFFER_SIZE = 1024 * 8;
public static String read(HttpServletRequest request) throws IOException {
BufferedReader bufferedReader = request.getReader();
for (Enumeration<String> iterator = request.getHeaderNames(); iterator.hasMoreElements();) {
String type = iterator.nextElement();
System.out.println(type+" = "+request.getHeader(type));
}
System.out.println();
StringWriter writer = new StringWriter();
write(bufferedReader,writer);
return writer.getBuffer().toString();
}
public static long write(Reader reader,Writer writer) throws IOException {
return write(reader, writer, BUFFER_SIZE);
}
public static long write(Reader reader, Writer writer, int bufferSize) throws IOException
{
int read;
long total = 0;
char[] buf = new char[bufferSize];
while( ( read = reader.read(buf) ) != -1 ) {
writer.write(buf, 0, read);
total += read;
}
return total;
}
2.2 定义Filter
@WebFilter
public class TestFilter implements Filter{
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain){
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
MyRequestWrapper wrapper = WebUtils.getNativeRequest(request, MyRequestWrapper.class);
chain.doFilter(wrapper == null ? new MyRequestWrapper(request) :wrapper,servletRequest);
}
}
使用的SpringBoot v2.1.x版本
Form提交无问题
获取RequestBody无问题
使用SpringBoot v2.2.0以上版本(包括v2.3.x)
Form提交无法获取参数
获取RequestBody无问题
经过排查,v2.2.x对比v2.1.x的不同在于一下代码差异:
BufferedReader bufferedReader = request.getReader();
-----------------
char[] buf = new char[bufferSize];
while( ( read = reader.read(buf) ) != -1 ) {
writer.write(buf, 0, read);
total += read;
}
当表单提交时
v2.1.x无法read到内容,读取结果为-1
v2.2.x、v2.3.x能够读取到内容
当表单提交时(x-www-form-urlencoded),inputStream读取一次后后续不会触发wrapper的getInputStream操作,所以Controller无法获取到参数。
MyRequestWrapper改造
public class MyRequestWrapper extends HttpServletRequestWrapper {
private final String body;
public MyRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
this.body = getBodyString(request);
}
public String getBody() {
return body;
}
public String getBodyString(final HttpServletRequest request) throws IOException {
String contentType = request.getContentType();
String bodyString = "";
StringBuilder sb = new StringBuilder();
if (StringUtils.isNotBlank(contentType) && (contentType.contains("multipart/form-data") || contentType.contains("x-www-form-urlencoded"))) {
Map<String, String[]> parameterMap = request.getParameterMap();
for (Map.Entry<String, String[]> next : parameterMap.entrySet()) {
String[] values = next.getValue();
String value = null;
if (values != null) {
if (values.length == 1) {
value = values[0];
} else {
value = Arrays.toString(values);
}
}
sb.append(next.getKey()).append("=").append(value).append("&");
}
if (sb.length() > 0) {
bodyString = sb.toString().substring(0, sb.toString().length() - 1);
}
return bodyString;
} else {
return IOUtils.toString(request.getInputStream());
}
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body.getBytes());
return new ServletInputStream() {
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public int read() {
return bais.read();
}
@Override
public void setReadListener(ReadListener readListener) {
}
};
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.getInputStream()));
}
}
默认配置时,
getInputStream()和getReader()一起使用会报错
使用两遍getInputStream(),第二遍会为空
当存在@RequestBody等注解时,springMVC已读取过一遍流,默认单独使用getInputStream()或getReader()都为空。
解决:写filter继承HttpServletRequestWrapper,缓存InputStream,覆盖getInputStream()和getReader()方法,使用ByteArrayInputStream is = new ByteArrayInputStream(body.getBytes());读取InputStream。
注意:springboot中,过滤器只需@Component即可生效,另外可在FilterRegistrationBean中配置路径和优先级。
对于拦截器,必须在InterceptorRegistry中调用addInterceptor方法。(路径可链式添加)
只能读一遍,类似管子。
只承担传输职责,而与处理和存储无关。
对于byte流而言,进行重复读取易于实现,但指针不重置,应是为了与InputStream接口定义保持一致。
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