Java动态从外部加载groovy脚本并执行。因为java可以直接把对象绑定到groovy脚本中执行，所以完全可以把一些系统中不确定的处理留下钩子，用groovy脚本处理，逻辑变了就直接改脚本，不用走发布流程。

核心代码

  1. CompilerConfiguration conf = new CompilerConfiguration();
  2. conf.setDebug(false);
  3. shell = new GroovyShell(conf);
  4. String extCP = "/extlib/xxx.jar";
  5. shell.getClassLoader().addClasspath(extCP);
  7. String scriptName = "Script.groovy";
  8. String scriptText = "String hello(){ return args[0] }";
  9. Script script = (Class<Script>) shell.parse(scriptText, scriptName).getClass();
  10. Thread.currentThread().setContextClassLoader(shell.getClassLoader());
  11. //获取groovy代码中的hello方法
  12. Method method = script.getDeclaredMethod("hello");
  13. Script instance = script.newInstance();
  14. Map bindings = instance.getBinding().getVariables();
  15. bindings.clear();
  16. //绑定args全局变量
  17. bindings.put("args", args);
  18. String ret = method.invoke(instance);
  19. bindings.clear();

依赖

  1. <dependency>
  2.   <groupId>org.codehaus.groovy</groupId>
  3.   <artifactId>groovy-json</artifactId>
  4.   <version>2.5.4</version>
  5.   <scope>provided</scope>
  6. </dependency>
  7. <dependency>
  8.   <groupId>org.codehaus.groovy</groupId>
  9.   <artifactId>groovy-sql</artifactId>
  10.   <version>2.5.4</version>
  11.   <scope>provided</scope>
  12. </dependency>
  13. <!-- groovy-all does not include groovy-dateutil by default, so must explicitly 
  14.    include it here -->
  15. <dependency>
  16.   <groupId>org.codehaus.groovy</groupId>
  17.   <artifactId>groovy-dateutil</artifactId>
  18.   <version>2.5.4</version>
  19. </dependency>
  20. <dependency>
  21.   <groupId>org.codehaus.groovy</groupId>
  22.   <artifactId>groovy-jsr223</artifactId>
  23.   <version>2.5.4</version>
  24. </dependency>

优化

可以根据脚本内容/脚本id等对script / method 来进行缓存，避免每次执行都要编译。编译会有大量的时间消耗，并造成metaspace增长。