通过httpClient请求文件流（普通文件和压缩文件）示例-白红宇

通过httpClient请求文件流（普通文件和压缩文件）示例

阅读量：4544 次

发布时间：2019-06-08

本文共 9845 字，大约阅读时间需要 32 分钟。

前言：通过浏览器请求文件流进行文件下载这里就不说了，网上有很多例子，这里主要是记录一下工作中的另一个场景，一个服务器通过HTTPClient向另一个服务请求文件流，在内存中进行业务逻辑处理，并不需要下载到本地，当然，如果你想要下载本地也是可以的，把文件流写到本地磁盘就可以了，也可以写到文件系统中。废话不多说。

备注（下面所说的压缩文件都是.gz格式的）

一，服务器传输的是普通的文件流，没有经过压缩

服务器：

@RequestMapping(value = "/getCommonFile", method = RequestMethod.POST)    public void getFile(HttpServletResponse response) {        BufferedInputStream buffInputStream = null;        OutputStream outputStream = null;        try {            buffInputStream = new BufferedInputStream(new FileInputStream(new File("D:\\testFile\\test.txt")));            outputStream = response.getOutputStream();            byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，这里配置的大一些            int len = 0;            while((len = buffInputStream.read(buff)) > 0) {                //把文件流写入到response的输出流中，供请求端请求                outputStream.write(buff, 0, len);                outputStream.flush();            }        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if(buffInputStream != null) {                    buffInputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }            try {                if(outputStream != null) {                    outputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }

客户端：

public void getCommonFile() throws IOException {        //从服务器请求文件流，具体代码就不贴了        CloseableHttpResponse response = HttpSender.toPost(FILE_URL, null);        InputStream inputStream = response.getEntity().getContent();        ByteArrayOutputStream byteArray = new ByteArrayOutputStream();        byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，这里配置的大一些        int len = 0;        while((len = inputStream.read(buff)) > 0) {            //把从服务端读取的文件流保存到ByteArrayOutputSteam中            byteArray.write(buff, 0, len);            byteArray.flush();        }        inputStream.close();        response.close();        BufferedReader bufferedReader = new BufferedReader(                new InputStreamReader(new ByteArrayInputStream(byteArray.toByteArray()), "utf-8"));        String line = null;        while((line = bufferedReader.readLine()) != null) {            System.out.println(line);        }

二，服务器传输的是压缩的文件流（直接读取的压缩文件）

@RequestMapping(value = "/getZipFile", method = RequestMethod.POST)    public void getZipFile(HttpServletResponse response) {        BufferedInputStream buffInputStream = null;        OutputStream outputStream = null;        try {            buffInputStream = new BufferedInputStream(new FileInputStream(new File("D:\\testFile\\test.gz")));            outputStream = response.getOutputStream();            byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，这里配置的大一些            int len = 0;            while((len = buffInputStream.read(buff)) > 0) {                //把文件流写入到response的输出流中，供请求端请求                outputStream.write(buff, 0, len);                outputStream.flush();            }        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if(buffInputStream != null) {                    buffInputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }            try {                if(outputStream != null) {                    outputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }

客户端：

public void getZipFile() throws IOException {        //从服务器请求文件流，具体代码就不贴了        CloseableHttpResponse response = HttpSender.toPost(FILE_URL, null);        InputStream inputStream = response.getEntity().getContent();        ByteArrayOutputStream byteArray = new ByteArrayOutputStream();        byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，这里配置的大一些        int len = 0;        while((len = inputStream.read(buff)) > 0) {            //把从服务端读取的文件流保存到ByteArrayOutputSteam中            byteArray.write(buff, 0, len);            byteArray.flush();        }        inputStream.close();        response.close();        //GZIPInputstream解压文件，然后读取文件        BufferedReader bufferedReader = new BufferedReader(                new InputStreamReader(new GZIPInputStream(                        new ByteArrayInputStream(byteArray.toByteArray())), "utf-8"));        String line = null;        while((line = bufferedReader.readLine()) != null) {            System.out.println(line);        }    }

三，服务器传输的是压缩的文件流（直接读取的普通文件，然后在内存中将文件流进行压缩）

@RequestMapping(value = "/getCommontToZipFile", method = RequestMethod.POST)    public void getCommontToZipFile(HttpServletRequest request, HttpServletResponse response) {        BufferedInputStream buffInputStream = null;        OutputStream outputStream = null;        GZIPOutputStream zipOut = null;        try {            outputStream = response.getOutputStream();            buffInputStream = new BufferedInputStream(new FileInputStream(new File("D:\\testFile\\test.txt")));            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();            //压缩文件            zipOut = new GZIPOutputStream(byteArrayOutputStream);            byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，这里配置的大一些            int len = 0;            while((len = buffInputStream.read(buff)) > 0) {                //把文件流写入到byteArrayOutputStream里面                zipOut.write(buff, 0, len);                zipOut.flush();            }            outputStream.write(byteArrayOutputStream.toByteArray());        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if(buffInputStream != null) {                    buffInputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }            try {                if(outputStream != null) {                    outputStream.close();                }            } catch (IOException e) {                e.printStackTrace();            }            try {                if(zipOut != null) {                    zipOut.close();                }            } catch (IOException e) {                e.printStackTrace();            }        }    }

客户端：

和第二种情况的客户端代码一样，就不贴代码了

四，直接读取多个压缩文件，把多个压缩文件流写在一个byteArray中

服务端：

@RequestMapping(value = "/getMultiZipFile", method = RequestMethod.POST)    public void getMultiZipFile(HttpServletRequest request, HttpServletResponse response) {        ByteArrayOutputStream byteArray = new ByteArrayOutputStream();        List
     
       files = new ArrayList
      
       ();        File file = new File("D:\\testFile\\test1.gz");        files.add(file);        file = new File("D:\\testFile\\test2.gz");        files.add(file);        for(File file1 : files) {            readDetailDataToByteArray(byteArray, file1);        }　　　　  writeToResponse(byteArray, response);    }    public static void readDetailDataToByteArray(ByteArrayOutputStream byteArray, File file) {        BufferedInputStream bufferedInputStream = null;        try {            bufferedInputStream = new BufferedInputStream(new FileInputStream(file));            byte[] b = new byte[1024*1024];            int j;            while ((j = bufferedInputStream.read(b)) > 0) {                byteArray.write(b, 0, j);                byteArray.flush();            }        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            try {                if(bufferedInputStream != null) {                    bufferedInputStream.close();                }            } catch (Exception e) {            }        }    }private void writeToResponse(ByteArrayOutputStream byteArray, HttpServletResponse response) {    OutputStream outputStream = null;    ByteArrayInputStream inputStream = null;    response.addHeader(HttpHeaders.CONTENT_TYPE, "utf-8");    response.addHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=test.gz" );    GZIPOutputStream zipOut = null;    ByteArrayOutputStream zipOutByteArray = new ByteArrayOutputStream();    try {            outputStream = response.getOutputStream();            zipOut = new GZIPOutputStream(zipOutByteArray);            inputStream = new ByteArrayInputStream(byteArray.toByteArray());            byte[] b = new byte[Integer.parseInt(buffSize)];            int j;            while ((j = inputStream.read(b)) > 0) {                zipOut.write(b, 0, j);                zipOut.flush();            } 　　　　　　　//这里的zipOut一定要关闭，要不然客户端接收到的压缩流写到本地后，打开会报错            zipOut.close();            outputStream.write(zipOutByteArray.toByteArray());        } catch (IOException e1) {                    }finally {                        try {                if(zipOutByteArray != null) {                    zipOutByteArray.close();                }            } catch (Exception e) {                            }            try {                if(byteArray != null) {                    byteArray.close();                }            } catch (Exception e) {                            }            try {                if(inputStream != null) {                    inputStream.close();                }            } catch (Exception e) {                            }            try {                if(outputStream != null) {                    outputStream.close();                }            } catch (Exception e) {                            }        }    }

客户端：

和第二种情况的客户端代码一样，就不贴代码了

转载于:https://www.cnblogs.com/jianyong-long/p/9693061.html

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