SpringBoot v2.2以上重复读取Request Body内容的解决方案

SpringBoot v2.2以上重复读取Request Body内容的解决方案

目录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

SpringBoot v2.2以上重复读取Request Body内容

一、需求

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

二、解决方案

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 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;

MyRhttp://equestWrapper wrapper = WebUtils.getNativeRequest(request, MyRequestWrapper.class);

chain.doFilter(wrapper == null ? new MyRequestWrapper(request) :wrapper,servletRequest);

}

}

三、遇到问题

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

四、问题排查

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。

解决方案

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(finalGniUal 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 parameterMap = request.getParameterMap();

for (Map.Entry 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 ServletInlGniUaputStream 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()));

}

}

SpringBoot 读取Request参数的坑

后端拿参数相关

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-，必须在InterceptorlGniUaRegistry中调用addInterceptor方法。（路径可链式添加）

关于流

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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