Spring boot integrated python engine quick start demo

一、Python introduction

Python is a high-level scripting language that combines interpreted, compiled, interactive and object-oriented scripting. Python is designed to be highly readable. Compared with other languages, it often uses English keywords and some punctuation marks in other languages. It has a more distinctive grammatical structure than other languages.

二、Code Project

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springboot-demo</artifactId>
        <groupId>com.et</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>python</artifactId>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-python -->
        <dependency>
            <groupId>org.python</groupId>
            <artifactId>jython-standalone</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

application.yaml

server:
  port: 8088

DemoApplication.java

package com.et.python;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
}

Code repository

• https://github.com/Harries/springboot-demo

1. Directly execute python statements in the java class

package com.et.python.util;
import org.python.util.PythonInterpreter;
public class JavaRunPython {
    
    public static void main(String[] args) {
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.exec("a='hello world'; ");
        interpreter.exec("print a;");
    }
}

result

hello world

2. Call the python script directly in java

create a python script in resource/py directory，file named test.py，file contents as follows：

a = 1
b = 2
print (a + b)

JavaPythonFile.java

package com.et.python.util;
import org.python.util.PythonInterpreter;
public class JavaPythonFile {
    public static void main(String[] args) {
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.execfile("D:\\IdeaProjects\\ETFramework\\python\\src\\main\\resources\\py\\test.py");
    }
}

result

3

3.use Runtime.getRuntime() to execute python script(recommend)

Create a python script in the resource/py folder. The file name is runtime.py. The file content is as follows:

print('RuntimeDemo')

RuntimeFunction.java

etc: Some codes may trigger sensitive words, so they can only be replaced with pictures.

execute

RuntimeDemo

4. call the function in the python script

create a python script in the resource/py folder，file name add.py，the file content as follows：

def add(a,b):
    return a + b

Function.java

package com.et.python.util;
import org.python.core.PyFunction;
import org.python.core.PyInteger;
import org.python.core.PyObject;
import org.python.util.PythonInterpreter;
public class Function {
    
    public static void main(String[] args) {
        PythonInterpreter interpreter = new PythonInterpreter();
        interpreter.execfile("D:\\IdeaProjects\\ETFramework\\python\\src\\main\\resources\\py\\add.py");      
        PyFunction pyFunction = interpreter.get("add", PyFunction.class);
        int a = 5, b = 10;
        PyObject pyobj = pyFunction.__call__(new PyInteger(a), new PyInteger(b)); 
        System.out.println("the anwser is: " + pyobj);
    }
}

result

the anwser is: 15

四、reference

• http://www.liuhaihua.cn/archives/710307.html
• https://developer.aliyun.com/article/1055469