前言

JDK6加入对JSR233-Java平台脚本的支持（），可以用来在Java程序中调用脚本。

1.支持的脚本类型

import javax.script.ScriptEngineFactory;import javax.script.ScriptEngineManager;import java.util.List;public class TestSupport {    public static void main(String[] args) {        ScriptEngineManager scriptEngineManager = new ScriptEngineManager();        List
    
      engineFactories = scriptEngineManager.getEngineFactories();        if (engineFactories.size() == 0) {            System.out.println("本JVM尚不支持任何脚本引擎");            return;        }        System.out.println("本JVM支持的脚本引擎有:");        for (ScriptEngineFactory engineFactory : engineFactories) {            System.out.println("引擎名称:" + engineFactory.getEngineName());            System.out.println("\t可被ScriptEngineManager识别的名称:" + engineFactory.getNames());            System.out.println("\t该引擎支持的脚本语言名称:" + engineFactory.getLanguageName());            System.out.println("\t是否线程安全:" + engineFactory.getParameter("THREADING"));        }    }}

2.DEMO

import javax.script.ScriptEngine;import javax.script.ScriptEngineManager;public class TestScript1 {    public static void main(String[] args) throws Exception {        ScriptEngineManager scriptEngineManager = new ScriptEngineManager();        ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("javascript");        String exp = "c=a+b;if(c<0){'负数'}else if(c==0){'零'}else{c};";        scriptEngine.put("a", Math.random()*(-10));        scriptEngine.put("b", Math.random()*10);        Object result = scriptEngine.eval(exp);        System.out.println(exp + " === " + result);    }}

2.commons-jexl

Apache commons-jexl是基于JSR233的扩展库，只需添加依赖就可以使用。

(1)Maven Dependency


        
     
      org.apache.commons
         
     
      commons-jexl
         
     
      2.1.1

(2)DEMO

import java.util.Date;public class Pojo {    private String str;    private Integer inte;    private Boolean bool;    private Date date;    public Pojo(String str, Integer inte, Boolean bool, Date date) {        this.str = str;        this.inte = inte;        this.bool = bool;        this.date = date;    }    public String getStr() {        return str;    }    public void setStr(String str) {        this.str = str;    }    public Integer getInte() {        return inte;    }    public void setInte(Integer inte) {        this.inte = inte;    }    public Boolean getBool() {        return bool;    }    public void setBool(Boolean bool) {        this.bool = bool;    }    public Date getDate() {        return date;    }    public void setDate(Date date) {        this.date = date;    }}

import com.google.common.collect.Lists;import com.google.common.collect.Maps;import org.apache.commons.jexl2.Expression;import org.apache.commons.jexl2.JexlContext;import org.apache.commons.jexl2.JexlEngine;import org.apache.commons.jexl2.MapContext;import java.util.Date;import java.util.List;import java.util.Map;public class TestJexl {    public static void main(String[] args) {        /**         * 新建或取回JexlEngine         */        JexlEngine jexl = new JexlEngine();        /**         * 初始化一个JexlContext对象，它代表一个执行JEXL表达式的上下文环境         */        JexlContext context = new MapContext();        // 准备并设置JEXL表达式上下文环境        Pojo pojo = new Pojo("Pojo", 123, true, new Date());        List
    
      list = Lists.newArrayList("a1", "", "c3");        Map
     
       map = Maps.newHashMap();        map.put("key", "value");        map.put("pojo", pojo);        context.set("pojo", pojo);        context.set("list", list);        context.set("map", map);        // 准备表达式        List
      
        jexlExps = Lists.newArrayList("pojo.str", "pojo.inte", "pojo.bool", "pojo.date"                , "size(list)", "list[0].length()", "list[0].toUpperCase()", "empty(list[1])"                , "map['key']", "map['pojo'].str");        // 执行表达式        for (String jexlExp : jexlExps) {            // 建立表达式对象 Create expression object            Expression expression = jexl.createExpression(jexlExp);            // 传入上下文环境并执行            Object obj = expression.evaluate(context);            System.out.println(expression.getExpression() + " = " + obj);        }    }}