1. 问题描述
Java平台要调用Pyhon平台已有的算法，为了减少耦合度，采用Pyhon平台提供Restful 接口，Java平台负责来调用，采用Http+Json格式交互。
2. 解决方案
2.1 JAVA平台侧
2.1.1 项目代码
public static String invokeAlgorithm(String url, HashMap params) throws Exception { HttpHeaders headers = new HttpHeaders(); headers.setContentType(MediaType.parseMediaType("application/json; charset=UTF-8")); headers.add("Accept", MediaType.APPLICATION_JSON.toString()); HttpEntity<String> httpEntity = new HttpEntity<>(JSONObject.toJSONString(params), headers); RestTemplate rst = new RestTemplate(); ResponseEntity<String> stringResponseEntity = rst.postForEntity(url, httpEntity, String.class); return stringResponseEntity.getBody(); }
2.1.2 代码解析
两个入参：url为Python提供restful调用方法；params参数，项目中参数使用了map，然后将map转成了Json，与Python服务器约定Json格式传输。
2.2 python平台侧
经过反复调研与深思熟虑的考虑后，决定采用flask提供Rest接口， flask 是一款非常流行的python web框架，微框架、简洁，社区活跃等。（其实是因为安装的Anaconda自带了flask，一配置一启动好了，就是这么巧）
2.2.1 项目代码
# -*- coding: utf-8 -*-from flask import Flask, request, send_from_directoryfrom k_means import execapp = Flask(__name__)import logging@app.route('/')def index(): return "Hello, World!"# k-means算法@app.route('/getKmeansInfoByPost', methods=['POST'])def getKmeansInfoByPost(): try: result = exec(request.get_json()) except IndexError as e: logging.error(str(e)) return 'exception:' + str(e) except KeyError as e: logging.error(str(e)) return 'exception:' + str(e) except ValueError as e: logging.error(str(e)) return 'exception:' + str(e) except Exception as e: logging.error(str(e)) return 'exception:' + str(e) else: return result@app.route("/<path:filename>")def getImages(filename): return send_from_directory(dirpath, filename, as_attachment=True)if __name__ == '__main__': app.run(host="0.0.0.0", port=5000, debug=True)
2.2.2 代码解析
代码为真实项目示例，去掉了一些配置而已，示例中包含三个方法，分别说一下
（1）最基本Rest接口：helloword
# -*- coding: utf-8 -*-from flask import Flaskapp = Flask(__name__)@app.route('/')def index(): return "Hello, World!"if __name__ == '__main__': app.run(host="0.0.0.0", port=5000, debug=True)
（2）调用其他python文件的Rest接口
# -*- coding: utf-8 -*-from flask import Flask, requestfrom k_means import execapp = Flask(__name__)import logging# k-means算法@app.route('/getKmeansInfoByPost', methods=['POST'])def getKmeansInfoByPost(): try: result = exec(request.get_json()) except IndexError as e: logging.error(str(e)) return 'exception:' + str(e) except KeyError as e: logging.error(str(e)) return 'exception:' + str(e) except ValueError as e: logging.error(str(e)) return 'exception:' + str(e) except Exception as e: logging.error(str(e)) return 'exception:' + str(e) else: return resultif __name__ == '__main__': app.run(host="0.0.0.0", port=5000, debug=True)
说明：1.接收POST方法；2. 从request获取java传过来的参数，对应上面的java调用代码
（3） 文件下载Rest接口
# -*- coding: utf-8 -*-from flask import Flask, send_from_directoryapp = Flask(__name__)@app.route("/<path:filename>")def getImages(filename): return send_from_directory(dirpath, filename, as_attachment=True)if __name__ == '__main__': app.run(host="0.0.0.0", port=5000, debug=True)
说明：1.还是flask框架提供的：send_from_directory
2.dirpath目录，一般可以给个固定存放目录，调用的时候只用给文件名称就可以直接下载对应文件。
2.3 Linux服务器启动python服务
nohup python restapi.py &
