JAVA使用脚本引擎执行JS

不念不忘少年蓝@ 2022-08-04 17:59 158阅读 0赞

import java.io.File;
    import java.lang.reflect.Field;
    import java.util.Arrays;
    
    import javax.script.Invocable;
    import javax.script.ScriptEngine;
    import javax.script.ScriptEngineManager;
    import javax.script.ScriptException;
    
    public class JavaExecScriptDemo {
      
      public static void main(String[] args) {
        System.out.println(jsObjFunc());
        System.out.println(Arrays.toString(getArray()));
        System.out.println(jsCalculate("a=1+2+3+(2*2)"));
        jsFunction();
        jsVariables();
      }
    
      /**
       * 运行JS对象中的函数
       * 
       * @return
       */
      public static Object jsObjFunc() {
        String script =
            "var obj={run:function(){return 'run method : return:\"abc'+this.next('test')+'\"';},next:function(str){return ' 我来至next function '+str+')'}}";
        ScriptEngineManager sem = new ScriptEngineManager();
        ScriptEngine scriptEngine = sem.getEngineByName("js");
        try {
          scriptEngine.eval(script);
          Object object = scriptEngine.get("obj");
          Invocable inv2 = (Invocable) scriptEngine;
          return (String) inv2.invokeMethod(object, "run");
        } catch (Exception e) {
          e.printStackTrace();
        }
        return null;
      }
    
      /**
       * 获取js对象数字类型属性
       * 
       * @return
       */
      public static Object[] getArray() {
        ScriptEngineManager sem = new ScriptEngineManager();
        String script = "var obj={array:['test',true,1,1.0,2.11111]}";
    
        ScriptEngine scriptEngine = sem.getEngineByName("js");
        try {
          scriptEngine.eval(script);
          Object object2 = scriptEngine.eval("obj.array");
          Class<?> clazz = object2.getClass();
          Field denseField = clazz.getDeclaredField("dense");
          denseField.setAccessible(true);
          return (Object[]) denseField.get(object2);
        } catch (Exception e) {
          e.printStackTrace();
        }
        return null;
      }
    
      /**
       * JS计算
       * 
       * @param script
       * @return
       */
      public static Object jsCalculate(String script) {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("javascript");
        try {
          return (Object) engine.eval(script);
        } catch (ScriptException ex) {
          ex.printStackTrace();
        }
        return null;
      }
    
      /**
       * 运行JS基本函数
       */
      public static void jsFunction() {
        ScriptEngineManager sem = new ScriptEngineManager();
        ScriptEngine se = sem.getEngineByName("javascript");
        try {
          String script = "function say(name){ return 'hello,'+name; }";
          se.eval(script);
          Invocable inv2 = (Invocable) se;
          String res = (String) inv2.invokeFunction("say", "test");
          System.out.println(res);
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
    
      /**
       * JS中变量使用
       */
      public static void jsVariables() {
        ScriptEngineManager sem = new ScriptEngineManager();
        ScriptEngine engine = sem.getEngineByName("javascript");
        File file = new File("/data/js.txt");
        engine.put("file", file);
        try {
          engine.eval("println('path:'+file.getAbsoluteFile())");
        } catch (ScriptException e) {
          e.printStackTrace();
        }
    
      }
    }

执行Main函数返回结果如下

run method : return:"abc 我来至next function test)"

\[test, true, 1.0, 1.0, 2.11111\]

10.0

hello,test

path:/data/js.txt