一.需求背景
算法团队使用python作为开发语言,web系统的开发人员使用java,web系统提供了一些页面操作,用户点击
按钮之后,java调用python脚本进行处理。
二.错误的选择
这个项目之前,笔者并没有过java系统调用python的经验,并且项目时间紧张,使用了最直接的调用方式,就是本地环境调用java脚本。代码如下:
public static boolean invokePython(String[] args){ try { String line = null; Process proc = Runtime.getRuntime().exec(args);// 执行py文件 BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream(), "utf-8")); //gbk 避免汉字乱码 List<String> list = Lists.newArrayList(); while ((line = in.readLine()) != null) { //logger.info(line); list.add(line); } in.close(); int exitVal=proc.waitFor(); logger.info("res:"+exitVal); /**Process exitValue: 0 调用python脚本成功 Process exitValue: 1 java调用python失败 Process exitValue: 2 python脚本执行失败**/ if(exitVal==0){ return true; } if(exitVal==2){ logger.warn("java调用python失败",JSON.toJSON(args)); return false; } else{ logger.warn("python脚本执行失败",JSON.toJSON(args)); return false; } } catch (IOException e) { logger.warn("invokePython_fail_param_{}",JSON.toJSON(args),e); return false; } catch (InterruptedException e) { logger.warn("invokePython_fail_param_{}",JSON.toJSON(args),e); System.out.println(e.getStackTrace()); return false; } }
这种方式有很多弊端,
1.最明显的就是python脚本单独运行并没有问题,但是java调用时就报错了,主要是项目路径,项目字符集的问题
2.本地开发环境配置复杂,python脚本只能放在本地,所以java开发人员还要配置python的环境,大部分python第三方包还是很好装,有的像tensorflow这种就会有不少问题,windows环境下,python3.5支持tensorflow,其他的3.6,3.7目前并不支持
3.调试起来麻烦,java调用脚本,脚本一旦报错的话,由于不能打断点,就要在加一些print和try catch去判断哪里出问题,这种方式对于简单代码还可以,复杂的话就要花不少时间。
由于以上几个弊端,笔者对此种调用方式深恶痛绝
三.http接口调用的方式
摆在面前的出路是python提供http服务,这就需要我们搭建一个python的框架,这里我使用了Django,Django框架搭建起来
并不复杂,具体做法可以自行百度。
搭建好Django之后,需要增加java发送http请求的工具类,代码如下:
public static String httpGetRequest(String url) throws Exception { CloseableHttpClient httpClient = HttpClients.createDefault(); // HttpClient httpclient = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(url); httpGet.setHeader("ContentType", "application/x-www-form-urlencoded;charset=UTF-8"); // 创建UrlEncodedFormEntity对象 HttpResponse response = httpClient.execute(httpGet); String html = extractContent(response); httpClient.close(); return html; }
public static String httpPostRequest(String url, Map<String, String> params) throws Exception { CloseableHttpClient httpClient = HttpClients.createDefault(); try{ // HttpClient httpclient = new DefaultHttpClient(); /** liupeng加入 读取超时时间=3分钟,默认=1分钟 */ // httpClient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 3*60*1000); // httpClient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 3*60*1000); RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(3*60*1000).setConnectTimeout(3*60*1000).build(); HttpPost httpPost = new HttpPost(url); httpPost.setHeader("ContentType", "application/x-www-form-urlencoded;charset=UTF-8"); httpPost.setConfig(requestConfig); List<NameValuePair> parameters = new ArrayList<NameValuePair>(); for (String key : params.keySet()) { parameters.add(new BasicNameValuePair(key, params.get(key))); } // 创建UrlEncodedFormEntity对象 UrlEncodedFormEntity formEntiry = new UrlEncodedFormEntity(parameters, "UTF-8"); httpPost.setEntity(formEntiry); HttpResponse response = httpClient.execute(httpPost); if(response != null){ logger.info("httpPostRequest11: " + response.toString()); }else{ logger.info("httpPostRequest22 "); } String html = extractContent(response); return html; }catch(Exception e){ logger.error(" httpPostRequest ",e); throw new RuntimeException(e); } finally { if (null != httpClient) { httpClient.close(); } } }
private static String extractContent(HttpResponse response) throws Exception { String htmStr = null; logger.info(" extractContentgetStatusCode " + response.getStatusLine().getStatusCode()); logger.info(" content " + response.getEntity().getContent().toString()); if (response.getStatusLine().getStatusCode() == 200) { if (response != null) { HttpEntity entity = response.getEntity(); InputStream ins = entity.getContent(); BufferedReader br = new BufferedReader(new InputStreamReader(ins, "UTF-8")); StringBuffer sbf = new StringBuffer(); String line = null; while ((line = br.readLine()) != null) { sbf.append(line); } br.close(); // 处理内容 htmStr = sbf.toString(); } }else{ if (response != null) { HttpEntity entity = response.getEntity(); InputStream ins = entity.getContent(); BufferedReader br = new BufferedReader(new InputStreamReader(ins, "UTF-8")); StringBuffer sbf = new StringBuffer(); String line = null; while ((line = br.readLine()) != null) { sbf.append(line); } br.close(); // 处理内容 htmStr = sbf.toString(); logger.info(" 处理内容:" + htmStr); } return ""; //失败时记录日志,但是结果返回空值 } return htmStr; }
调用时发现报了Forbidden (CSRF cookie not set.): 错误:
临时解决方案:修改settings.py文件,注释掉django.middleware.csrf.CsrfViewMiddleware'。
post请求可以使用这种方式接收