基于google aviator的表达式引擎

介绍

Aviator是一个轻量级、高性能的Java表达式执行引擎，它动态地将表达式编译成字节码并运行。可被用于动态的公式计算、规则执行和过滤等场景

 

jar 包依赖

<dependency>
	<groupId>com.googlecode.aviatorgroupId>
	<artifactId>aviatorartifactId>
	<version>4.2.0version>
dependency>

 

牛刀小试

案例1

public class AnswerApp {

    public static void main(String[] args) throws Exception {
        // 表达式
        String express = "x*x+y*y";

        Expression expression = AviatorEvaluator.compile(express);

        // 表达式中 x的值设置为 10, y的值设置为5
        Map<String, Object> params = ImmutableMap.of("x", 10, "y", 5);

        Object result = expression.execute(params);

        System.out.println("result: "+ result);
    }
}

程序运行结果

result: 125

 

案例2

public class AnswerApp {

    public static void main(String[] args) throws Exception {
        Long result = (Long) AviatorEvaluator.execute("10 * 10 + 5 * 5");
        System.out.println("result: " + result);

		System.out.println();

        String name = "Answer.AI.L";
        String language = "Java";
        Map<String, Object> map = ImmutableMap.of("myProp1", name, "myProp2", language);
        Object result1 = AviatorEvaluator.execute("'Hello ' + myProp1 + ', Hello ' + myProp2", map);
        System.out.println("result1: " + result1);
    }
}

程序运行结果

result: 125

result1: Hello Answer.AI.L, Hello Java

 

案例3-内置函数

public class AnswerApp {

    public static void main(String[] args) throws Exception {
    	// ns
        System.out.println(AviatorEvaluator.execute("string.substring('AnswerAIL',1,3)"));
		
		// true
        System.out.println(AviatorEvaluator.execute("string.contains(\"AnswerAIL\",\"AI\")"));

		// true
        System.out.println(AviatorEvaluator.execute("string.contains(\"Answer\",string.substring('AnswerAIL',1,3))"));

		// 求n次方  
		AviatorEvaluator.execute("math.pow(-3,2)");   
		// 开平方根  
		AviatorEvaluator.execute("math.sqrt(14.0)"); 
		// 正弦函数    
		AviatorEvaluator.execute("math.sin(20)");    
    }
}

 

案例4-自定义函数

public class MySumFunction extends AbstractFunction {

    @Override
    public AviatorObject call(Map<String, Object> env, AviatorObject a, AviatorObject b, AviatorObject c) {
        Number numA = FunctionUtils.getNumberValue(a, env);
        Number numB = FunctionUtils.getNumberValue(b, env);
        Number numC = FunctionUtils.getNumberValue(c, env);

        long result = numA.longValue() + numB.longValue() + numC.longValue();
//        return new AviatorDouble(numA.longValue() + numB.longValue() + numC.longValue());
        return AviatorLong.valueOf(result);
    }

    /**
     * 获取函数名
     * */
    @Override
    public String getName() {
        return "mySum";
    }
}


public class AnswerApp {

    public static void main(String[] args) throws Exception {
        // 注册函数
        AviatorEvaluator.addFunction(new MySumFunction());

        String expression = "mySum(x, y, z)";

        Map<String, Object> params = ImmutableMap.of("x", 1, "y", 2, "z", 3);

        long result = (long) AviatorEvaluator.execute(expression, params);

        System.out.printf("result : " + result);

    }
}

程序运行结果

result : 6

 

Reference

• Aviator 表达式的使用
• aviator jar 包
• Aviator 表达式求值引擎开源框架