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Java调用groovy Java调用groovy实现原理代码实例

小白菜aaa 人气:1

一、概述

Groovy is a multi-faceted language for the Java platform.

Apache Groovy是一种强大的、可选的类型化和动态语言,具有静态类型和静态编译功能,用于Java平台,目的在于通过简洁、熟悉和易于学习的语法提高开发人员的工作效率。它可以与任何Java程序顺利集成,并立即向您的应用程序提供强大的功能,包括脚本编写功能、特定于域的语言编写、运行时和编译时元编程以及函数式编程。

Groovy是基于java虚拟机的,执行文件可以是简单的脚本片段,也可以是一个完整的groovy class,对于java程序员来说,学习成本低,可以完全用java语法编写。

二、java项目执行groovy必要环境

    <dependency>
      <groupId>org.codehaus.groovy</groupId>
      <artifactId>groovy-all</artifactId>
      <version>2.4.16</version>
    </dependency>
    <dependency>
      <groupId>org.kohsuke</groupId>
      <artifactId>groovy-sandbox</artifactId>
      <version>1.7</version>
    </dependency>

三、java项目执行groovy方式

3.1 ScriptEngineManager

groovy遵循JSR 223标准,可以使用jdk的标准接口ScriptEngineManager调用。

@org.junit.Test
public void scriptEngineManager() throws ScriptException, NoSuchMethodException {
 ScriptEngineManager factory = new ScriptEngineManager();
 // 每次生成一个engine实例
 ScriptEngine engine = factory.getEngineByName("groovy");
 System.**out**.println(engine.toString());
 // javax.script.Bindings
 Bindings binding = engine.createBindings();
 binding.put("date", new Date());
 // 如果script文本来自文件,请首先获取文件内容
 engine.eval("def getTime(){return date.getTime();}", binding);
 engine.eval("def sayHello(name,age){return 'Hello,I am ' + name + ',age' + age;}");
 Long time = (Long) ((Invocable) engine).invokeFunction("getTime", null);// 反射到方法
 System.**out**.println(time);
 String message = (String) ((Invocable) engine).invokeFunction("sayHello", "zhangsan", 12);
 System.**out**.println(message);
}

((Invocable) engine).invokeFunction(方法名,…参数)

3.2 GroovyShell

直接使用GroovyShell,执行groovy脚本片段,GroovyShell每一次执行时代码时会动态将代码编译成java class,然后生成java对象在java虚拟机上执行,所以如果使用GroovyShell会造成class太多,性能较差。

@org.junit.Test
public void testGroovyShell() {
 final String script = "Runtime.getRuntime().availableProcessors()";

 Binding intBinding = new Binding();
 GroovyShell shell = new GroovyShell(intBinding);

 final Object eval = shell.evaluate(script);
 System.**out**.println(eval);
}

3.3 GroovyClassLoader

groovy官方提供GroovyClassLoader从文件,url或字符串中加载解析Groovy class

@org.junit.Test
public void testGroovyClassLoader() throws IllegalAccessException, InstantiationException {
 GroovyClassLoader groovyClassLoader = new GroovyClassLoader();
 String hello = "package com.szwn.util" + 
     "class GroovyHello {" + 
      "String sayHello(String name) {" + 
       "print 'GroovyHello call'" + 
       "name" + 
      "}" + 
     "}";
 Class aClass = groovyClassLoader.parseClass(hello);
 GroovyObject object = (GroovyObject) aClass.newInstance();
 Object o = object.invokeMethod("sayHello", "zhangsan");
 System.out.println(o.toString());
}

3.4 GroovyScriptEngine

GroovyScriptEngine可以从url(文件夹,远程协议地址,jar包)等位置动态加装resource(script或则Class),同时对

编译后的class字节码进行了缓存,当文件内容更新或者文件依赖的类更新时,会自动更新缓存。

@org.junit.Test
public void testGroovyScriptEngine() throws IOException, ResourceException, groovy.util.ScriptException {
 String url = "...(文件地址)";
 GroovyScriptEngine engine = new GroovyScriptEngine(url);
 for (int i = 0; i < 5; i++) {
  Binding binding = new Binding();
  binding.setVariable("index", i);
  // 每一次执行获取缓存Class,创建新的Script对象
  Object run = engine.run("HelloWorld.groovy", binding);
  System.out.println(run);
 }
}

四、安全

4.1 SecureASTCustomizer

Groovy会自动引入java.util,java.lang包,方便用户调用,但同时也增加了系统的风险。为了防止用户调用System.exit或Runtime等方法导致系统宕机,以及自定义的groovy片段代码执行死循环或调用资源超时等问题,Groovy提供了SecureASTCustomizer安全管理者和SandboxTransformer沙盒环境。

@org.junit.Test
public void testAST() {
 final String script = "import com.alibaba.fastjson.JSONObject;JSONObject object = new JSONObject()";
 // 创建SecureASTCustomizer
 final SecureASTCustomizer secure = new SecureASTCustomizer();
 // 禁止使用闭包
 secure.setClosuresAllowed(true);
 List<Integer> tokensBlacklist = new ArrayList<>();
 // 添加关键字黑名单 while和goto
 tokensBlacklist.add(Types.**KEYWORD_WHILE**);
 tokensBlacklist.add(Types.**KEYWORD_GOTO**);
 secure.setTokensBlacklist(tokensBlacklist);
 // 设置直接导入检查
 secure.setIndirectImportCheckEnabled(true);
 // 添加导入黑名单,用户不能导入JSONObject
 List<String> list = new ArrayList<>();
 list.add("com.alibaba.fastjson.JSONObject");
 secure.setImportsBlacklist(list);
 // statement 黑名单,不能使用while循环块
 List<Class<? extends Statement>> statementBlacklist = new ArrayList<>();
 statementBlacklist.add(WhileStatement.class);
 secure.setStatementsBlacklist(statementBlacklist);
 // 自定义CompilerConfiguration,设置AST
 final CompilerConfiguration config = new CompilerConfiguration();
 config.addCompilationCustomizers(secure);
 Binding intBinding = new Binding();
 GroovyShell shell = new GroovyShell(intBinding, config);
 final Object eval = shell.evaluate(script);
 System.out.println(eval);
}

SecureASTCustomizer :属性

tokensBlacklist 关键字黑名单

ImportsBlacklist 导入黑名单

statementBlacklist statement 黑名单

如果代码块中出现黑名单限制的内容,则会抛出异常

4.2 SandboxTransformer

用户调用System.exit或调用Runtime的所有静态方法都会抛出SecurityException

@org.junit.Test
 public void testGroovySandbox() {
  // 自定义配置
  CompilerConfiguration config = new CompilerConfiguration();
  // 添加线程中断拦截器,可拦截循环体(for,while)、方法和闭包的首指令
  config.addCompilationCustomizers(new ASTTransformationCustomizer(ThreadInterrupt.class));
  // 添加线程中断拦截器,可中断超时线程,当前定义超时时间为3s
  Map<String, Object> timeoutArgs = new HashMap<>();
  timeoutArgs.put("value", 3);
  config.addCompilationCustomizers(new ASTTransformationCustomizer(timeoutArgs, TimedInterrupt.class));
  // 沙盒环境
  config.addCompilationCustomizers(new SandboxTransformer());
  GroovyShell sh = new GroovyShell(config);
  // 注册至当前线程
  new NoSystemExitSandbox().register();
  new NoRunTimeSandbox().register();
  // 确保在每次更新缓存Class<Script>对象时候,采用不同的groovyClassLoader
  Script groovyScript = sh.parse("System.exit(1)");
  Object run = groovyScript.run();
  System.**out**.println(run);
 }
 class NoSystemExitSandbox extends GroovyInterceptor {
  @Override
  public Object onStaticCall(GroovyInterceptor.Invoker invoker, Class receiver, String method, Object... args) throws Throwable {
   if (receiver == System.class && method.equals("exit")) {
    throw new SecurityException("No call on System.exit() please");
   }
   return super.onStaticCall(invoker, receiver, method, args);
  }
 }
 class NoRunTimeSandbox extends GroovyInterceptor {
  @Override
  public Object onStaticCall(GroovyInterceptor.Invoker invoker, Class receiver, String method, Object... args) throws Throwable {
   if (receiver == Runtime.class) {
    throw new SecurityException("No call on RunTime please");
   }
   return super.onStaticCall(invoker, receiver, method, args);
  }
 }

五、groovy代码块调用java代码注意事项

5.1 java代码行/代码块

Java代码可以直接放在groovy方法体/代码块中运行

def hello = {name ->
System.out.println(name)
}

等同于

def helli = {name ->
println(name)
}

5.2 获取java对象

5.2.1 new

直接通过new 来获取

def newJavaObject(){
 DpDeptCopyInfo deptCopyInfo = new DpDeptCopyInfo();
 println(deptCopyInfo)
}
newJavaObject();

5.2.2 spring bean

不能使用@Autowired(autowired是在spring启动后注入的,此时还未加载groovy代码,故无法注入)

建议实现ApplicationContextAware接口的工具(组件)来获取spring bean

@Component
public final class SpringUtils implements BeanFactoryPostProcessor
{
 /** Spring应用上下文环境 \*/
 private static ConfigurableListableBeanFactory beanFactory;

 @Override
 public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException
 {
  SpringUtils.beanFactory = beanFactory;
 }
 @SuppressWarnings("unchecked")
 public static <T> T getBean(String name) throws BeansException
 {
  return (T) beanFactory.getBean(name);
 }
 public static <T> T getBean(Class<T> clz) throws BeansException
 {
  T result = (T) beanFactory.getBean(clz);
  return result;
 }
}

例:

被调用的groovy代码

def springTransfer = {name ->
  println("==============================开始groovy====================================")
  QueryDataDaoService daoService = SpringUtils.getBean(QueryDataDaoService.class);
  println("对象:" + daoService)
  println("==============================结束groovy====================================")
  println("==============================返回传入参数====================================")
  return name
}
springTransfer(name)

Java代码:

  @Test
  public void testGroovySpringTransfer() throws IOException, ResourceException, ScriptException {
    //获取 groovy脚本文件的绝对路径
    String filePath = "文件路径";
    GroovyScriptEngine engine = new GroovyScriptEngine(filePath);
    //执行获取缓存Class,创建新的Script对象
    Object run = engine.run("SpringTransfer.groovy", "ladq");
    System.out.println("执行groovy结果:" + run);
  }

执行结果

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