怎么解决在controller中无法二次读取的问题

发布时间：2021-10-26 14:35:31 作者：iii
来源：亿速云阅读：152

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拦截器中读取request参数,在controller中无法二次读取

新建类

package com.ouyeelbuy.mc.common.base; 
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
 
/**
 * @author robin.zhang
 * @date $
 * @description 解决在request的数据流只能读取一次的问题
 */
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 = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
 
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        body = stringBuilder.toString();
    }
 
    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        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 byteArrayInputStream.read();
            }
        };
        return servletInputStream; 
    }
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
 
    public String getBody() {
        return this.body;
    }
}

添加过滤器

package com.ouyeelbuy.mc.common.filter;
import com.ouyeelbuy.mc.common.base.RequestWrapper;
import org.springframework.stereotype.Component; 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
 
/**
 * @author robin.zhang
 * @date $
 * @description 解决request数据流只能读取一次的问题
 */
@Component
public class RequestFilter 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) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            filterChain.doFilter(requestWrapper, servletResponse);
        }
    }
 
    @Override
    public void destroy() {
    }
}

然后注册这个过滤器到spring容器中，问题解决！

使用拦截器时，controller中不能再次获取body中的参数

报错信息：从报错信息可以看出，io流已经关闭。这是由于拦截器读取了body中的参数信息，导致controller不能再次读取。

I/O error while reading input message; nested exception is java.io.IOException: Stream closed

解决办法

在拦截器读取到body信息后，再次将内容写入

1、获取body信息

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
import java.nio.charset.Charset;
 
/**
 * 保存流
 */
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
    private final byte[] body; 
    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
        String sessionStream = getBodyString(request);
        body = sessionStream.getBytes(Charset.forName("UTF-8"));
    }
 
    /**
     * 获取请求Body
     *
     * @param request
     * @return
     */
    public String getBodyString(final ServletRequest request) {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        try {
            inputStream = cloneInputStream(request.getInputStream());
            reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
 
    /**
     * Description: 复制输入流</br>
     *
     * @param inputStream
     * @return</br>
     */
    public InputStream cloneInputStream(ServletInputStream inputStream) {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len;
        try {
            while ((len = inputStream.read(buffer)) > -1) {
                byteArrayOutputStream.write(buffer, 0, len);
            }
            byteArrayOutputStream.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
        InputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
        return byteArrayInputStream;
    }
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
 
    @Override
    public ServletInputStream getInputStream() throws IOException { 
        final ByteArrayInputStream bais = new ByteArrayInputStream(body); 
        return new ServletInputStream() {
 
            @Override
            public int read() throws IOException {
                return bais.read();
            }
 
            @Override
            public boolean isFinished() {
                return false;
            }
 
            @Override
            public boolean isReady() {
                return false;
            }
 
            @Override
            public void setReadListener(ReadListener readListener) {
            }
        };
    }
}

2、重新写入

import org.springframework.core.annotation.Order;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
// 表示执行过滤顺序，值越小，越先执行
@Order(1)
// 配置需要过滤的地址
@WebFilter(filterName = "bodyReaderFilter", urlPatterns = "/*")
public class BodyReaderFilter implements Filter {
 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
//        System.out.println("--------------过滤器初始化------------");
    }
 
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
//        System.out.println("--------------执行过滤操作------------");
 
        // 防止流读取一次后就没有了, 所以需要将流继续写出去
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper(httpServletRequest);
        filterChain.doFilter(requestWrapper, servletResponse);
    }
 
    @Override
    public void destroy() {
//        System.out.println("--------------过滤器销毁------------");
    } 
}

3、注册过滤器

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
 
@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
// 注册过滤器注解
@ServletComponentScan
public class WebPlatformApplication {
    public static void main(String[] args) {
        SpringApplication.run(WebPlatformApplication.class);
    }
}

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