解决HttpServletRequest无法获取@RequestBody修饰的参数问题及分析
作者：Spirit_NKlaus
Spring Boot中,@RequestBody读取请求体后流关闭,导致Service层无法获取,解决方案包括创建HTTP工具类、请求体复制包装器及拦截器配置,确保请求体可重复读取
HttpServletRequest无法获取@RequestBody修饰的参数
在使用springboot设计controller时我们通常会在某个请求如post中使用@RequestBody来修饰参数如：
在一些特殊场景下，我们需要在service层的代码去拿到当前上下文请求（HttpServletRequest）中的一些信息如请求体，这个时候被@RequestBody所修饰的请求是无法获取的。
原因如下：
1、请求体流只能读取一次：Servlet 规范中，HttpServletRequest 的输入流 (getInputStream()) 是单向的，一旦被 @RequestBody 读取后，流就会关闭，无法再次读取。
2、@RequestBody 优先处理：Spring MVC 在处理控制器方法时，会先解析 @RequestBody，导致后续通过 HttpServletRequest 获取请求体时为空。
下面简单演示下解决方案：
一、先编写一个http工具类用来读取ServletRequest的内容
import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.List;
/**
* http工具类
*/
@Slf4j
public class HttpUtils {
/**
* 从request获取body的数据
*
* @param request 请求
* @return body数据字符串
*/
public static String getBodyStr(ServletRequest request) {
StringBuilder sb = new StringBuilder();
try {
try (ServletInputStream inputStream = request.getInputStream()) {
try (BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8))) {
String line;
while ((line = reader.readLine()) != null) {
sb.append(line);
}
}
}
} catch (Exception e) {
log.error("get request body error: ", e);
}
return sb.toString();
}
/**
* 从request获取body的数据，并转换成对象（适用于使用@RequestBody修饰的参数）
*
* @param request request 请求
* @param clazz 对象类型
* @return 对象
*/
public static <T> T getBodyToObject(ServletRequest request, Class<T> clazz) {
String bodyStr = getBodyStr(request);
if (StringUtils.isBlank(bodyStr)) {
return null;
}
return JSON.parseObject(bodyStr, clazz);
}
/**
* 从request获取body的数据，并转换成集合对象（适用于使用@RequestBody修饰的参数）
*
* @param request request 请求
* @param clazz 集合对象类型
* @return 集合对象
*/
public static <T> List<T> getBodyToList(ServletRequest request, Class<T> clazz) {
String bodyStr = getBodyStr(request);
if (StringUtils.isBlank(bodyStr)) {
return null;
}
return JSON.parseArray(bodyStr, clazz);
}
}二、添加请求体复制包装器
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
/**
* 请求体复制包装器
*/
public class BodyCopyWrapper extends HttpServletRequestWrapper {
private byte[] requestBody;
public BodyCopyWrapper(HttpServletRequest request) throws IOException {
super(request);
requestBody = HttpUtils.getBodyStr(request).getBytes(StandardCharsets.UTF_8);
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream basis = new ByteArrayInputStream(requestBody);
return new ServletInputStream() {
@Override
public int read() throws IOException {
return basis.read();
}
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
};
}
public void setInputStream(byte[] body) {
this.requestBody = body;
}
}三、添加请求拦截器配置类
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
/**
* 请求拦截器配置类
*/
@Slf4j
@Configuration
public class FilterConfig {
@Bean
public FilterRegistrationBean<RequestWrapperFilter> requestWrapperFilter() {
FilterRegistrationBean<RequestWrapperFilter> bean = new FilterRegistrationBean<>();
bean.setFilter(new RequestWrapperFilter());
bean.addUrlPatterns("/*");
bean.setOrder(Ordered.HIGHEST_PRECEDENCE);
return bean;
}
public static class RequestWrapperFilter implements Filter {
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException
, IOException {
ServletRequest requestWrapper = null;
if (request instanceof HttpServletRequest) {
requestWrapper = new BodyCopyWrapper((HttpServletRequest) request);
}
if (null == requestWrapper) {
log.warn("未进行request包装返回原来的request");
chain.doFilter(request, response);
} else {
chain.doFilter(requestWrapper, response);
}
}
}
}四、业务代码中使用方式
HttpServletRequest request = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getRequest(); //转对象 UserLoginDTO userLoginDTO = HttpUtils.getBodyToObject(request, UserLoginDTO.class); //直接获取内容字符串 String bodyStr = HttpUtils.getBodyStr(request);
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。