Java中使用Python脚本及动态传参的方法

╰+攻爆jí腚メ 2022-09-05 13:55 197阅读 0赞

## 一、背景介绍 ##

在实际工作中需要使用JsonSchema解析json数据，JsonSchema中的新功能if-then-else在Java中无法生效，但是Python脚本就可以（咱也不知道为什么）。于是自己便生出一个想法，是否可以在Java中执行Python脚本呢？百度一番还真有这种操作

**pom.xml文件中需要引入相应的依赖包**

<dependency>
         <groupId>org.python</groupId>
         <artifactId>jython-standalone</artifactId>
         <version>2.7.0</version>
    </dependency>

## 二、使用Python的四种方法 ##

### 2.1 在Java类中直接执行Python语句 ###

@Test
    public void test1(){ 
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.exec("a='hello world'; ");
        interpreter.exec("print a;");
    }

### 2.2 在Java中直接调用Python脚本 ###

@Test
    public void test2(){ 
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.execfile("/Users/sundongping/python/JsonSchema7ForApiCase.py");
     }

### 2.3 使用Runtime.getRuntime()执行Python脚本文件，推荐使用 ###

@Test
        public void test3(){ 
            Process proc;
            String pythonPath = "/Users/xxxx/python/JsonSchema7ForApiCase.py";
            try { 
                String[] strings = { "python3", pythonPath};
                proc = Runtime.getRuntime().exec(strings);
                BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
                String line = null;
                while ((line = in.readLine()) != null) { 
                    System.out.println(line);
                }
                in.close();
                proc.waitFor();
            } catch (IOException e) { 
                e.printStackTrace();
            } catch (InterruptedException e) { 
                e.printStackTrace();
            }
        }

### 2.4 调用Python脚本中的函数 ###

@Test
    public void test4(){ 
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.execfile("/Users/xxxx/python/JsonSchema7ForApiCase.py");
    
        // 第一个参数为期望获得的函数（变量）的名字，第二个参数为期望返回的对象类型
        PyFunction pyFunction = interpreter.get("add", PyFunction.class);
        int a = 5, b = 10;
        //调用函数，如果函数需要参数，在Java中必须先将参数转化为对应的“Python类型”
        PyObject pyobj = pyFunction.__call__(new PyInteger(a), new PyInteger(b));
        System.out.println("the anwser is: " + pyobj);
    }

## 三、Java中实现Python脚本的动态传参 ##

@Test
    public void test5(){ 
         String inputStr2 = "{ \n" +
                " \"type\":\"object\",\n" +
                " \"properties\":{ \n" +
                " \"presp\":{ \n" +
                " \"type\":\"object\",\n" +
                " \"properties\":{ \n" +
                " \"pdata\":{ \n" +
                " \"type\":\"object\",\n" +
                " \"properties\":{ \n" +
                " \"flightBusyInfo\":{ \n" +
                " \"type\":\"object\"\n" +
                " },\n" +
                " \"flightInfo\":{ \n" +
                " \"type\":\"array\"\n" +
                " }\n" +
                " }\n" +
                " }\n" +
                " },\n" +
                " \"if\":{ \n" +
                " \"properties\":{ \n" +
                " \"pdata\":{ \n" +
                " \"type\":\"string\",\n" +
                " \"minProperties\":1\n" +
                " }\n" +
                " }\n" +
                " },\n" +
                " \"then\":{ \n" +
                " \"required\":[\n" +
                " \"pdata\"\n" +
                " ]\n" +
                " },\n" +
                " \"else\":{ \n" +
                " \"properties\":{ \n" +
                " \"pdata\":{ \n" +
                " \"minProperties\":1\n" +
                " }\n" +
                " }\n" +
                " }\n" +
                " }\n" +
                " }\n" +
                "}";
        String data2 = "{ \"pkey\":\"2021-08-17 17:29:58\",\"pname\":\"\",\"ppid\":\"1060030\",\"presp\":{ \"hinttype\":0,\"pdata\":{},\"perrcode\":0},\"pret\":1,\"pver\":\"\"}";
        
        try { 
              //设置命令行传入参数
              String[] args = new String[] {  "python3", "/Users/sundongping/python/test.py", inputStr2, data2};
              Process pr = Runtime.getRuntime().exec(args);
    
              BufferedReader in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
              String line;
              while ((line = in.readLine()) != null) { 
                  System.out.println(line);
              }
              in.close();
              pr.waitFor();
          } catch (Exception e) { 
              e.printStackTrace();
          }
    }