通过httpClient请求文件流（普通文件和压缩文件）示例

Posted 2021-01-08 jianyong-long

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。

 

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，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<File> files = new ArrayList<File>();
        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);
        }
    }

    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) {

            }
        }
    }

客户端：

和第二种情况的客户端代码一样，就 不贴代码了

 

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);
    }
}