java-接口返回PDF的相应输出方法-附带标准post代码

悠悠 2022-01-27 01:19 692阅读 0赞

背景：账单类接口返回很多都是默认返回PDF数据流的，这里提供一个测试通过的demo，附带原生post请求方法。

主要方法：

void postAction(String url, String filePatch) throws UnsupportedEncodingException, Exception {
            String filePath2 = "D:\\work\\test\\00066.pdf";
        	String str = FileUtil.getFileContent(filePatch);//流，见下
            System.out.println("读取文件报文：\n" + str);
            String aesXml = str;//本来是打算兼容xml格式或者json对象的，图方便直接读文件了
            System.out.println("aesXml: " +  aesXml);
            
            String response = this.doPost(url, aesXml);
            System.out.println("返回报文：response: " +  response);
            BufferedInputStream bin = null;
            FileOutputStream fout = null;
            BufferedOutputStream bout = null;
            byte[] srtbyte = response.getBytes();
            System.out.println("开始写入PDF文件。。。");
            long startTime = System.currentTimeMillis();
            try {
                //创建一个将bytes作为其缓冲区的ByteArrayInputStream对象
                ByteArrayInputStream bais = new ByteArrayInputStream(srtbyte);
    
                //创建从底层输入流中读取数据的缓冲输入流对象
                bin = new BufferedInputStream(bais);
                //指定输出的文件
                File file = new File(filePath2 );
                if (!file.exists()){
    
                    file.createNewFile();
                }
                //创建到指定文件的输出流
                fout= new FileOutputStream(file);
                //为文件输出流对接缓冲输出流对象
                bout = new BufferedOutputStream(fout);
                byte [] buffers = new byte[1024];
                int len = bin.read(buffers);
                while(len != -1){
                    bout.write(buffers, 0, len);
                    len = bin.read(buffers);
                }
                //刷新此输出流并强制写出所有缓冲的输出字节，必须这行代码，否则有可能有问题
                bout.flush();
            }catch(IOException e) {
                e.printStackTrace();
            }finally{
                try {
                    bin.close();
                    fout.close();
                    bout.close();
                    System.err.println("cost " + (System.currentTimeMillis() - startTime) + "ms");
                }catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

java-post方法：

String doPost(String requestUrl, String contentStr) throws Exception {
             HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
                public boolean verify(String hostname, SSLSession session) {  
                 return true;  
               }  
            };  
            
            PrintWriter printWriter = null;
            BufferedReader bufferedReader = null;
            StringBuffer responseResult = new StringBuffer();
            HttpURLConnection httpURLConnection = null;
            try {
               URL realUrl = new URL(requestUrl);
               // 打开和URL之间的连接
              HttpsURLConnection https = (HttpsURLConnection)realUrl.openConnection();  
              if (realUrl.getProtocol().toLowerCase().equals("https")) {  
                  https.setHostnameVerifier(DO_NOT_VERIFY);  
                  httpURLConnection = https;  
              } else {  
                  httpURLConnection = (HttpURLConnection)realUrl.openConnection();  
              }  
              //conn.connect(); 
                
               // 设置通用的请求属性
              httpURLConnection.setRequestMethod("POST"); // 设置请求方式  
              httpURLConnection.setRequestProperty("Accept", "application/xml"); // 设置接收数据的格式  
              httpURLConnection.setRequestProperty("Content-Type", "application/xml"); // 设置发送数据的格式  
              httpURLConnection.setRequestProperty("Charset", "UTF-8");
               // 发送POST请求必须设置如下两行
               httpURLConnection.setDoOutput(true);
               httpURLConnection.setDoInput(true);
               // Post 请求不能使用缓存
               httpURLConnection.setUseCaches(false);
               
               httpURLConnection.setConnectTimeout(1000 * 60);
               httpURLConnection.setReadTimeout(1000 * 60);
               
               // 获取URLConnection对象对应的输出流
               OutputStream os = httpURLConnection.getOutputStream();    
               os.write(contentStr.getBytes("UTF-8"));   
               os.close(); 
               
               // 根据ResponseCode判断连接是否成功
               int responseCode = httpURLConnection.getResponseCode();
               if (responseCode != HttpURLConnection.HTTP_OK) {
                    System.out.println("Error===" + responseCode);
               } else {
                    System.out.println("Post Success!");
               }
                
               // 定义BufferedReader输入流来读取URL的ResponseData
               bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream(), "UTF-8"));
               String line;
               while ((line = bufferedReader.readLine()) != null) {
                   responseResult.append("\n").append(line);
               }
            } catch (Exception e) {
               System.out.println("send post request error!" + e);
               throw e;
            } finally {
               httpURLConnection.disconnect();
               try {
                   if (printWriter != null) {
                       printWriter.close();
                   }
                   if (bufferedReader != null) {
                       bufferedReader.close();
                   }
               } catch (IOException ex) {
                    System.out.println("close source error!" + ex);
               }
        
            }
            
            return responseResult.toString();
        }

文件读取：

String getFileContent(String filePath){
            System.out.println("filePath: " + filePath);
            File file = new File(filePath);
            FileInputStream fis;
            String str = "";
            try {
                fis = new FileInputStream(file);
                BufferedReader in = new BufferedReader(new InputStreamReader(fis, "utf-8"));
                StringBuffer buffer = new StringBuffer();
                String line = "";
                while ((line = in.readLine()) != null) {
                        buffer.append(line);
                }
                str = buffer.toString();
                fis.close();
                in.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }