spring boot拦截器中获取request post请求中的参数

时间：2025-03-20 10:04:34

 

 

从拦截器中获取post请求的参数的需求，这里记录一下处理过程中出现的问题。
首先想到的就是(String )方法，但是这个方法只能在get请求中取到参数，post是不行的，后来想到了使用流的方式，调用()获取流，然后从流中读取参数，如下代码所示：

String body = "";
StringBuilder stringBuilder = new StringBuilder();
BufferedReader bufferedReader = null;
InputStream inputStream = null;
try {
    inputStream = ();
    if (inputStream != null) {
        bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        char[] charBuffer = new char[128];
        int bytesRead = -1;
        while ((bytesRead = (charBuffer)) > 0) {
            (charBuffer, 0, bytesRead);
        }
    } else {
        ("");
    }
} catch (IOException ex) {
    ();
} finally {
    if (inputStream != null) {
        try {
            ();
        }
        catch (IOException e) {
            ();
        }
    }
    if (bufferedReader != null) {
        try {
            ();
        }
        catch (IOException e) {
            ();
        }
    }
}
body = ();

代码中的body就是request中的参数，我这里传的是JSON数据：{"page": 1, "pageSize": 10}，那么body就是：body = "{"page": 1, "pageSize": 10}"，一个JSON字符串。这样是可以成功获取到post请求的body，但是，经过拦截器后，参数经过@RequestBody注解赋值给controller中的方法的时候，却抛出了一个这样的异常：

: Required request body is missing

在网上查找资料后发现，request的输入流只能读取一次，那么这是为什么呢？下面是答案：

那是因为流对应的是数据，数据放在内存中，有的是部分放在内存中。read 一次标记一次当前位置（mark position），第二次read就从标记位置继续读（从内存中copy）数据。 所以这就是为什么读了一次第二次是空了。 怎么让它不为空呢？只要inputstream 中的pos 变成0就可以重写读取当前内存中的数据。javaAPI中有一个方法public void reset() 这个方法就是可以重置pos为起始位置，但是不是所有的IO读取流都可以调用该方法！ServletInputStream是不能调用reset方法，这就导致了只能调用一次getInputStream()。

摘自：/sdut406/article/details/81369983

那么有什么办法可以用户解决呢？上面这篇博客中提到了解决方案，就是重写HttpServletRequestWrapper把request保存下来，然后通过过滤器把保存下来的request再填充进去，这样就可以多次读取request了。步骤如下所示：

①写一个类，继承HttpServletRequestWrapper

import ;
import ;
import ;
import ;
import .*;

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 = ();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = (charBuffer)) > 0) {
                    (charBuffer, 0, bytesRead);
                }
            } else {
                ("");
            }
        } catch (IOException ex) {

        } finally {
            if (inputStream != null) {
                try {
                    ();
                }
                catch (IOException e) {
                    ();
                }
            }
            if (bufferedReader != null) {
                try {
                    ();
                }
                catch (IOException e) {
                    ();
                }
            }
        }
        body = ();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(());
        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 ();
            }
        };
        return servletInputStream;

    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(()));
    }

    public String getBody() {
        return ;
    }

}

②拦截器层面

package ;

import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;
import .*;
import ;
import ;
import ;
import ;
import org.;
import org.;
import ;
import ;
import ;
import ;
import ;

import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;

@Component("authSecurityInterceptor")
public class AuthSecurityInterceptor extends HandlerInterceptorAdapter {
    private Logger logger = ();

    @Autowired
    private UsersService douYinUsersService;
    @Autowired
    private RedisCache redisCache;
    @Autowired
    private VisitLimitCount visitLimitCount;

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        try {
            RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
            String body = ();
            (body);
            return true;
        }catch (Exception e){
            ("权限判断出错",e);
        }
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
    }
}

③过滤器Filter，用来把request传递下去


import ;

import .*;
import ;
import ;
import ;

@WebFilter(urlPatterns = "/*",filterName = "channelFilter")
public class ChannelFilter 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) {
            (servletRequest, servletResponse);
        } else {
            (requestWrapper, servletResponse);
        }
    }
 
    @Override
    public void destroy() {

    }
}

④在启动类中注册拦截器

import ;
import ;
import ;
import ;
import ;
import ;
import ;

@SpringBootApplication
@ServletComponentScan  //注册过滤器注解
@Configuration
public class WebApplication {

    public static void main(String[] args) {
        (, args);
    }
}

经测试，问题解决

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