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在攔截器中讀取request參數(shù),解決在controller中無法二次讀取的問題

更新時間：2021年10月26日 11:28:47 作者：張子蘢

這篇文章主要介紹了在攔截器中讀取request參數(shù),解決在controller中無法二次讀取的問題，具有很好的參考價值，希望對大家有所幫助。如有錯誤或未考慮完全的地方，望不吝賜教

攔截器中讀取request參數(shù),在controller中無法二次讀取

新建類

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 解決在request的數(shù)據(jù)流只能讀取一次的問題
 */
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;
    }
}

添加過濾器

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 解決request數(shù)據(jù)流只能讀取一次的問題
 */
@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() {
    }
}

然后注冊這個過濾器到spring容器中，問題解決！

使用攔截器時，controller中不能再次獲取body中的參數(shù)

報錯信息：從報錯信息可以看出，io流已經(jīng)關(guān)閉。這是由于攔截器讀取了body中的參數(shù)信息，導(dǎo)致controller不能再次讀取。

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

解決辦法

在攔截器讀取到body信息后，再次將內(nèi)容寫入

1、獲取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"));
    }
 
    /**
     * 獲取請求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: 復(fù)制輸入流</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、重新寫入

import org.springframework.core.annotation.Order;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
// 表示執(zhí)行過濾順序，值越小，越先執(zhí)行
@Order(1)
// 配置需要過濾的地址
@WebFilter(filterName = "bodyReaderFilter", urlPatterns = "/*")
public class BodyReaderFilter implements Filter {
 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
//        System.out.println("--------------過濾器初始化------------");
    }
 
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
//        System.out.println("--------------執(zhí)行過濾操作------------");
 
        // 防止流讀取一次后就沒有了, 所以需要將流繼續(xù)寫出去
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper(httpServletRequest);
        filterChain.doFilter(requestWrapper, servletResponse);
    }
 
    @Override
    public void destroy() {
//        System.out.println("--------------過濾器銷毀------------");
    } 
}

3、注冊過濾器

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
// 注冊過濾器注解
@ServletComponentScan
public class WebPlatformApplication {
    public static void main(String[] args) {
        SpringApplication.run(WebPlatformApplication.class);
    }
}

添加完成后，運行正常！

以上為個人經(jīng)驗，希望能給大家一個參考，也希望大家多多支持腳本之家。

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