Java 调用 Javascript 函数的范例

桃扇骨 2022-06-16 01:37 246阅读 0赞

在Java 7 以后，可以在Java代码中调用javascript中的函数，请看下面的例子：

![复制代码][copycode.gif]

package com.lee;
    
    import java.io.FileNotFoundException;
    import java.io.FileReader;
    import java.util.Scanner;
    import javax.script.Bindings;
    import javax.script.Invocable;
    import javax.script.ScriptContext;
    import javax.script.ScriptEngine;
    import javax.script.ScriptEngineManager;
    import javax.script.ScriptException;
    
    /**
     *
     * @author liyanxue
     */
    public class JavaInvokeJS {
    
        public static void main(String[] args) throws FileNotFoundException, ScriptException, NoSuchMethodException {
            ScriptEngine engine = new ScriptEngineManager().getEngineByName("javascript" );
            Bindings bind = engine.createBindings();
            bind.put( "factor", 0);
            engine.setBindings(bind, ScriptContext. ENGINE_SCOPE);
    
            // 输入方式
            /*
             Scanner input = new Scanner(System.in);
             while (input.hasNextInt()) {
             int first = input.nextInt();
             int second = input.nextInt();
    
             System.out.println("输入的参数是：" + first + ", " + second);
             engine.eval(new FileReader("/Users/ liyanxue/model.js"));
    
             if (engine instanceof Invocable ) {
             Invocable in = (Invocable ) engine;
             // 执行 js函数
             Double result = (Double) in.invokeFunction("formula", first, second);
             System.out.println("运算结果是：" + result.intValue());
             }
             }
             */
            int first = 23;
            int second = 7;
    
            System. out.println("输入的参数是：" + first + ", " + second);
            engine.eval( new FileReader("/Users/liyanxue/model.js" ));
    
            if (engine instanceof Invocable) {
                Invocable in = (Invocable) engine;
                // 执行js函数
                Double result = (Double) in.invokeFunction( "formula", first, second);
                System. out.println("运算结果是：" + result.intValue());
            }
        }
    }

![复制代码][copycode.gif]

/Users/liyanxue/model.js里的代码：

function formula(var1, var2) {
         return var1 + var2 + factor;
    }

[copycode.gif]: /images/20220616/ad3b9100a58e4a3fb8f398db458de2ad.png