通過httpClient請求文件流（普通文件和壓縮文件）示例

前言：通過瀏覽器請求文件流進行文件下載這里就不說了，網上有很多例子，這里主要是記錄一下工作中的另一個場景，一個服務器通過HTTPClient向另一個服務請求文件流，在內存中進行業務邏輯處理，並不需要下載到本地，當然，如果你想要下載本地也是可以的，把文件流寫到本地磁盤就可以了，也可以寫到文件系統中。廢話不多說。

 備注（下面所說的壓縮文件都是.gz格式的）

一，服務器傳輸的是普通的文件流，沒有經過壓縮

服務器：

@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，這里配置的大一些
            int len = 0;
            while((len = buffInputStream.read(buff)) > 0) {
                //把文件流寫入到response的輸出流中，供請求端請求
                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();
            }
        }
    }

客戶端：

public void getCommonFile() throws IOException {
        //從服務器請求文件流，具體代碼就不貼了
        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，這里配置的大一些
        int len = 0;
        while((len = inputStream.read(buff)) > 0) {
            //把從服務端讀取的文件流保存到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，服務器傳輸的是壓縮的文件流（直接讀取的壓縮文件）

@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，這里配置的大一些
            int len = 0;
            while((len = buffInputStream.read(buff)) > 0) {
                //把文件流寫入到response的輸出流中，供請求端請求
                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();
            }
        }
    }

客戶端：

public void getZipFile() throws IOException {
        //從服務器請求文件流，具體代碼就不貼了
        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，這里配置的大一些
        int len = 0;
        while((len = inputStream.read(buff)) > 0) {
            //把從服務端讀取的文件流保存到ByteArrayOutputSteam中
            byteArray.write(buff, 0, len);
            byteArray.flush();
        }
        inputStream.close();
        response.close();

        //GZIPInputstream解壓文件，然后讀取文件
        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，服務器傳輸的是壓縮的文件流（直接讀取的普通文件，然后在內存中將文件流進行壓縮）

@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();
            //壓縮文件
            zipOut = new GZIPOutputStream(byteArrayOutputStream);
            byte[] buff = new byte[1024*1024]; //如果是稍微大的文件，這里配置的大一些
            int len = 0;
            while((len = buffInputStream.read(buff)) > 0) {
                //把文件流寫入到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();
            }
        }
    }

客戶端：

和第二種情況的客戶端代碼一樣，就 不貼代碼了

 

四，直接讀取多個壓縮文件，把多個壓縮文件流 寫在一個byteArray中

服務端：

@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);
        }
　　　　  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();
            }
　　　　　　　//這里的zipOut一定要關閉，要不然客戶端接收到的壓縮流寫到本地后，打開會報錯
            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) {
                
            }
        }
    }

客戶端：

和第二種情況的客戶端代碼一樣，就 不貼代碼了