Java 调用 python 的接口

    不管什么技术，不管什么问题，只要努力就能解决。    最近在做项目的时候，需要java 调用 python 接口，在网上找了一些方法，但是总碰到一些问题，索性将网上的方法和自己的理解总结一下，希望对各位博友有所帮助，也请各位大神不吝赐教。

一：创建环境 Python 环境

import org.python.util.PythonInterpreter;

import java.util.Properties;

/**
* Jython环境，获取Python的实例
* @author webim
*
*/
public class JythonEnvironment {

//定义一个静态变量
private static JythonEnvironment INSTANCE = new JythonEnvironment();

/**
* 私有构造方法
*/
private JythonEnvironment()
{
}

/**
* 获取单例
* @return JythonEnvironment
*/
public static JythonEnvironment getInstance()
{
return INSTANCE;
}

/**
* 获取python解释器
* @return PythonInterpreter
*/
public PythonInterpreter getPythonInterpreter()
{
Properties props = new Properties();
props.put("python.home","path to the Lib folder");
props.put("python.console.encoding", "UTF-8"); // Used to prevent: console: Failed to install '': java.nio.charset.UnsupportedCharsetException: cp0.
props.put("python.security.respectJavaAccessibility", "false"); //don't respect java accessibility, so that we can access protected members on subclasses
props.put("python.import.site","false");

Properties preprops = System.getProperties();
//对 python 进行初始化
PythonInterpreter.initialize(preprops, props, new String[0]);
PythonInterpreter inter = new PythonInterpreter();
return inter;
}

}

在创建 python 解释器之前，需要初始化 python 环境，参考过一些例子，是没有进行初始化，会进行报下列错误。org.python.core.PyException: nullat org.python.core.Py.ImportError(Py.java:330) ~[jython-2.7.1b3.jar:na]at org.python.core.Py.importSiteIfSelected(Py.java:1577) ~[jython-2.7.1b3.jar:na]at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:116) ~[jython-2.7.1b3.jar:na]at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:94) ~[jython-2.7.1b3.jar:na]at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:71) ~[jython-2.7.1b3.jar:na]at com.sihuatech.puzzlevideo.manage.controller.AAlarmController.getAllAlarmInfo(AAlarmController.java:85) ~[classes/:na]at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_152]at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_152]at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_152]at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_152]at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) [spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) [tomcat-embed-core-8.5.27.jar:8.5.27]at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) [tomcat-embed-core-8.5.27.jar:8.5.27]

二：调用 python 的接口

因为 python 和 java是两种不同的语言，因此在项目的 controller 、service 和 mapper 中直接出现 Python 的接口，因此自己封装 ExecPython 类，

封装python的接口，目的让 python 接口和java程序分隔开。

import org.python.core.PyFunction;import org.python.core.PyObject;import org.python.util.PythonInterpreter;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Component;import org.springframework.stereotype.Service;import java.util.Map;/*enum的这个用法,可以作为变种的安全单例,值得借鉴哦 ^_^ */@Service@Componentpublic class ExecPython {public static final Logger logger = LoggerFactory.getLogger(Exception.class);//定义 python 解释器private static PythonInterpreter inter;public ExecPython() {this.inter = JythonEnvironment.getInstance().getPythonInterpreter();this.inter.execfile("C:\\test.py");}//设置 python 脚本的路径public void setPythonPath (String pythonPath){this.inter.execfile(pythonPath);}public void execute(String scriptFile, Map<String,String> properties){logger.info("获取解释器");try{PyFunction getNetInfo = (PyFunction) inter.get("getNetInfo", PyFunction.class);PyObject netInfo = getNetInfo.__call__();System.out.println("anwser = " + netInfo.toString());}catch (Exception e){e.printStackTrace();logger.info("Python 脚本文件执行失败");}}//获取 Python 字符串public String getString(){

//获取到python 脚本中的接口
PyFunction func = (PyFunction) inter.get("adder", PyFunction.class);
PyObject pyobj = func.__call__();
System.out.println("anwser = " + pyobj.toString());
return pyobj.toString();
}
// 获取当前数组
public String getArr() {
PyFunction getArr = (PyFunction) inter.get("getArr", PyFunction.class);
PyObject pyobjTwo = getArr.__call__();
pyobjTwo.__len__();
System.out.println("anwser = " + pyobjTwo.toString()+" len:"+pyobjTwo.__len__());

//将 PyObject 对象转换成 java  对象
//Object object = pyobjTwo.__tojava__(List.class);
//List<String> list = (List<String>) object;

//将查询到数据转换成一个 JSON 字符串
String result = pyobjTwo.toString();
String JsonStr = "{" + result + "}";
logger.info(JsonStr);
logger.info("将查询的结果转换成 JSON 字符串：",JsonStr);

return pyobjTwo.toString();
}
}

三： python 脚本

def adder():       return "{'name':'leilei','age':'18'}"     def getArr():return ['aaa','bbb']def getNetInfo():return [{'DNS':'192.168.12.3','ip':'45.23.16.0'},{'DNS2':'192.168.12.2','ip2':'45.23.16.2'}]