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: null
at 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
@Component
public 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"}]