ScriptEngineManager的使⽤说明
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.script.SimpleBindings;
/**
* ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.eval(new FileReader("script.js"));
* @author chenyuanbao
*
*/
public class Test {
public static void main(String[] args) throws ScriptException {
exeVar();
exeFor();
exeCondition("0.01");
exeCondition1("8","8");
try {
putValue();
callJsFunction();
} catch (Exception e) {
e.printStackTrace();
}
}
//java将变量导⼊js脚本 2的8次⽅
public static void putValue() throws Exception{
String str="Math.pow(a,b)";
Map<String, Object>input=new TreeMap<>();
input.put("a",2);
input.put("b",8);
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
System.out.println(engine.eval(str,new SimpleBindings(input)));
}
//调⽤js函数
public static void callJsFunction() throws Exception{
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
engine.eval("function add (a, b) {return a+b; }");
Invocable jsInvoke = (Invocable) engine;
Object res = jsInvoke.invokeFunction("add", new Object[] { 10, 5 });
js获取json的key和valueSystem.out.println(res);
}
public static void exeCondition1(String x,String y) throws ScriptException{
List<String> conditions = new ArrayList<>();
conditions.add("x==0");//如果写x=0 报错，x==0则正常。
conditions.add("x>0&&y<10");
conditions.add("x>=10&&y<20");
conditions.add("x>=20&&y<30");
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
engine.put("x", x);
engine.put("y", y);
for(String script:conditions){
Boolean ret  = (Boolean) engine.eval(script);
System.out.println(script+"="+ret);
}
}
}
public static void exeCondition(String val) throws ScriptException{
List<String> conditions = new ArrayList<>();
conditions.add("x==0");//如果写x=0 报错，x==0则正常。
conditions.add("x>0&&x<1");
conditions.add("x>=1&&x<2");
conditions.add("x>=2&&x<3");
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
engine.put("x", val);
for(String script:conditions){
Boolean ret  = (Boolean) engine.eval(script);
System.out.println(script+"="+ret);
}
}
public static void exeVar() throws ScriptException{
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
Double hour = (Double) engine.eval("var date = new Date();" + "Hours();");
System.out.println("hour : " + hour);
}
public static void exeFor() throws ScriptException{
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
engine.put("name", "abcdefg");//倒置⼀个字符串
engine.eval("var output ='' ;" + "for (i = 0; i <= name.length; i++) { " + " output = name.charAt(i) + output"    + "}");
String name = (String) ("output");
System.out.printf("被翻转后的字符串：%s \n", name);
}
//该函数测试Java与js对象
public static void getObject() throws Exception{
String str = "  var obj=new Object();    "
+ "  obj.info='hello world';  "
+ "  Info=function(){  "
+ "        return this.info;  "
+ "  };                        ";
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
engine.eval(str);
//获取对象
ScriptObjectMirror obj=(ScriptObjectMirror) ("obj");
//输出属性
System.out.("info"));
System.out.("getInfo"));
str="Info()";
//执⾏⽅法
System.out.println(engine.eval(str));
}
//该函数测试Java获取JS变量值的能⼒
public static void getJsValue() throws Exception{
String str = "  var msg='hello';          "
+ "  var number = 123;        "
+ "  var array=['A','B','C'];  "
+ "  var json={                "
+ "      'name':'pd',          "
+ "      'subjson':{          "
+ "          'subname':'spd'  "
+ "          ,'id':123        "
+ "          }                "
+ "      };                    ";
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = EngineByName("javascript");
ScriptEngine engine = EngineByName("javascript");
//执⾏语句
engine.eval(str);
str="msg+=' world';number+=5";
//再次执⾏
engine.eval(str);
//获取js变量msg（String类型）
System.out.("msg"));
//获取js变量msg（int类型）
System.out.("number"));
//获取js变量array（数组）
ScriptObjectMirror array=(ScriptObjectMirror) ("array");        //getSlot（int index）函数⽤于获取下标为index的值
System.out.Slot(0));
//获取js变量json（json类型）
ScriptObjectMirror json=(ScriptObjectMirror) ("json");
//get（String key）函数⽤于键key的值
System.out.("name"));
//获取js变量subjson（嵌套json类型）
ScriptObjectMirror subjson=(("subjson");        System.out.("subname"));
}
//参考⽂档
}

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