Spring中集成Groovy的四种方式(小结)

groovy是一种动态脚本语言，适用于一些可变、和规则配置性的需求，目前Spring提供ScriptSource接口，支持两种类型，一种是

ResourceScriptSource，另一种是 StaticScriptSource，但是有的场景我们需要把groovy代码放进DB中，所以我们需要扩展这个。

ResourceScriptSource：在 resources 下面写groovy类

StaticScriptSource：把groovy类代码放进XML里

DatabaseScriptSource：把groovy类代码放进数据库中

工程模块为：

ResourceScriptSource

groovy的pom

  <dependency>
      <artifactId>groovy-all</artifactId>
      <groupId>org.codehaus.groovy</groupId>
      <version>2.1.9</version>
      <scope>compile</scope>
    </dependency>

HelloService接口

package com.maple.resource.groovy;

/**
 * @author: maple
 * @version: HelloService.java, v 0.1 2020年09月25日 21:26 maple Exp $
 */
public interface HelloService {

  String sayHello();
}

resources下面建groovy实现类

package com.maple.resource.groovy

class HelloServiceImpl implements HelloService {

  String name;

  @Override
  String sayHello() {
    return "Hello $name. Welcome to resource in Groovy.";
  }
}

在spring-groovy.xml中配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:lang="http://www.springframework.org/schema/lang"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
              http://www.springframework.org/schema/lang
              http://www.springframework.org/schema/lang/spring-lang.xsd">

  <lang:groovy id="helloService" script-source="classpath:groovy/HelloServiceImpl.groovy">
    <lang:property name="name" value="maple"></lang:property>
  </lang:groovy>

</beans>

主类 GroovyResourceApplication

package com.maple.resource;

import com.maple.resource.groovy.HelloService;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.support.ClassPathXmlApplicationContext;

@SpringBootApplication
public class GroovyResourceApplication {

  public static void main(String[] args) {

    //SpringApplication.run(GroovyResourceApplication.class, args);

    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring-groovy.xml");

    HelloService bean = context.getBean(HelloService.class);

    String sayHello = bean.sayHello();

    System.out.println(sayHello);
  }

}

启动并测试

StaticScriptSource

groovy的pom

 <dependency>
      <artifactId>groovy-all</artifactId>
      <groupId>org.codehaus.groovy</groupId>
      <version>2.1.9</version>
      <scope>compile</scope>
    </dependency>

HelloService接口

package com.maple.groovy.staticscript.groovy;

/**
 * @author: maple
 * @version: HelloService.java, v 0.1 2020年09月25日 21:26 maple Exp $
 */
public interface HelloService {

  String sayHello();
}

在spring-groovy.xml中配置具体的实现类

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:lang="http://www.springframework.org/schema/lang"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
              http://www.springframework.org/schema/beans/spring-beans.xsd
              http://www.springframework.org/schema/lang
              http://www.springframework.org/schema/lang/spring-lang.xsd">

  <lang:groovy id="helloService">

    <lang:inline-script>

      import com.maple.groovy.staticscript.groovy.HelloService

      class HelloServiceImpl implements HelloService {

        String name;

        @Override
        String sayHello() {
          return "Hello $name. Welcome to static script in Groovy.";
        }
      }

    </lang:inline-script>

    <lang:property name="name" value="maple"/>

  </lang:groovy>

</beans>

主类 GroovyStaticscriptApplication

package com.maple.groovy.staticscript;

import com.maple.groovy.staticscript.groovy.HelloService;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.support.ClassPathXmlApplicationContext;

@SpringBootApplication
public class GroovyStaticscriptApplication {

  public static void main(String[] args) {

    //SpringApplication.run(GroovyStaticscriptApplication.class, args);

    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring-groovy.xml");

    HelloService bean = context.getBean(HelloService.class);

    String sayHello = bean.sayHello();

    System.out.println(sayHello);
  }

}

启动并测试

DatabaseScriptSource

下面我们先建表，把基本工作做完，这里我使用mybatisplus，dao、service等代码省略

CREATE TABLE `groovy_script` (
`id` BIGINT ( 20 ) NOT NULL AUTO_INCREMENT,
`script_name` VARCHAR ( 64 ) NOT NULL COMMENT 'script name',
`script_content` text NOT NULL COMMENT 'script content',
`status` VARCHAR ( 16 ) NOT NULL DEFAULT 'ENABLE' COMMENT 'ENABLE/DISENABLE',
`extend_info` VARCHAR ( 4096 ) DEFAULT NULL,
`created_time` TIMESTAMP ( 6 ) NOT NULL DEFAULT CURRENT_TIMESTAMP ( 6 ),
`modified_time` TIMESTAMP ( 6 ) NOT NULL DEFAULT CURRENT_TIMESTAMP ( 6 ) ON UPDATE CURRENT_TIMESTAMP ( 6 ),
PRIMARY KEY ( `id` )
) ENGINE = INNODB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8mb4 COMMENT = 'groovy script';

INSERT INTO `gane-platform`.`groovy_script`(`id`, `script_name`, `script_content`, `status`, `extend_info`, `created_time`, `modified_time`) VALUES (1, 'helloService', 'package com.maple.resource.groovy\r\n\r\nimport com.maple.database.groovy.HelloService\r\n\r\npublic class HelloServiceImpl implements HelloService {\r\n\r\n  @Override\r\n  String sayHello(String name) {\r\n    return \"Hello \"+name+\". Welcome to database in Groovy.\";\r\n  }\r\n}', 'ENABLE', NULL, '2020-09-26 17:16:36.477818', '2020-09-27 08:23:10.790553');

方法一：

1、实时读取DB里的groovy脚本文件

2、利用GroovyClassLoader去编译脚本文件

3、把class对象注入成Spring bean

4、反射调用脚本的方法

package com.maple.database.controller;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.maple.database.entity.GroovyScript;
import com.maple.database.groovy.SpringContextUtils;
import com.maple.database.service.GroovyScriptService;
import groovy.lang.GroovyClassLoader;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * @author: maple
 * @version: GroovyController.java, v 0.1 2020年09月26日 17:18 maple Exp $
 */
@RestController
public class GroovyController {

  @Resource
  private GroovyScriptService groovyScriptService;

  @GetMapping("/groovyTest")
  private String groovyTest() throws IllegalAccessException, InstantiationException, InvocationTargetException, NoSuchMethodException {

    GroovyScript groovyScript = groovyScriptService.getOne(new QueryWrapper<GroovyScript>()
        .eq("script_name", "helloService").eq("status", "ENABLE"));

    System.out.println(groovyScript.getScriptContent());

    Class clazz = new GroovyClassLoader().parseClass(groovyScript.getScriptContent());

    Object o = clazz.newInstance();

    SpringContextUtils.autowireBean(o);

    Method method = clazz.getMethod("sayHello", String.class);

    return (String) method.invoke(o, "maple");
  }
}

package com.maple.database.groovy;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @author: maple
 * @version: SpringContextUtils.java, v 0.1 2020年09月26日 17:29 maple Exp $
 */
@Component
public class SpringContextUtils implements ApplicationContextAware {

  static ApplicationContext context;

  @Override
  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    SpringContextUtils.context = applicationContext;
  }

  public static void autowireBean(Object bean) {
    context.getAutowireCapableBeanFactory().autowireBean(bean);
  }

  public static ApplicationContext getContext() {
    return context;
  }

  public static <T> T getBean(Class<T> clazz) {
    return context.getBean(clazz);

  }

  public static <T> T getBean(String name) {
    return (T) context.getBean(name);

  }
}

启动测试结果为：

总结：

优点：实时读取DB里的脚本，当脚本更改时，可以直接修改DB，对代码无侵入

缺点：每次都要查询DB，反射调用代码写死了

方法二：

1、我们模仿groovy-resource的思路，resource的XML配置是下面这样的

<lang:groovy id="helloService" script-source="classpath:groovy/HelloServiceImpl.groovy" />

所以，我们可以把DatabaseScriptSource的XML保存成这种格式

<lang:groovy id="helloService" script-source="database:helloService"/>

2、然后模仿Spring保存成XML格式的document的思路，我们也把groovy保存成XML格式的document，放进内存里

3、groovy的关键处理类是ScriptFactoryPostProcessor，当 Spring 装载应用程序上下文时，它首先创建工厂 bean（例如 GroovyScriptFactory bean）。然后，执行ScriptFactoryPostProcessor bean，用实际的脚本对象替换所有的工厂 bean。例如，我们本次测试的配置产生一个名为 helloService 的 bean，它的类型是groovierspring.GroovyHelloService。（如果启用 Spring 中的 debug 级日志记录，并观察应用程序上下文的启动，将会看到 Spring 首先创建一个名为 scriptFactory.helloService 的工厂 bean，然后 ScriptFactoryPostProcessor 从该工厂 bean 创建 helloService bean）。

我们发现ScriptFactoryPostProcessor这个类中，有getScriptSource这个方法，该方法里有convertToScriptSource方法

在convertToScriptSource这个方法中，他默认支持我们前面说过的static script和resource两种类型，但是现在我们新增了一种database类型，所以我们需要重写该方法，其他的工作都一样，交给ScriptFactoryPostProcessor帮我们去处理。

package com.maple.database.manage;

import com.maple.database.groovy.DatabaseScriptSource;
import org.apache.commons.lang3.StringUtils;
import org.springframework.core.io.ResourceLoader;
import org.springframework.scripting.ScriptSource;
import org.springframework.scripting.support.ResourceScriptSource;
import org.springframework.scripting.support.ScriptFactoryPostProcessor;
import org.springframework.scripting.support.StaticScriptSource;
import org.springframework.stereotype.Component;

/**
 * @author: maple
 * @version: CustomerScriptFactoryPostProcessor.java, v 0.1 2020年09月26日 20:36 maple Exp $
 */
@Component
public class CustomerScriptFactoryPostProcessor extends ScriptFactoryPostProcessor {

  @Override
  protected ScriptSource convertToScriptSource(String beanName, String scriptSourceLocator, ResourceLoader resourceLoader) {

    if (scriptSourceLocator.startsWith(INLINE_SCRIPT_PREFIX)) {
      return new StaticScriptSource(scriptSourceLocator.substring(INLINE_SCRIPT_PREFIX.length()), beanName);

    }

    if (scriptSourceLocator.startsWith(GroovyConstant.SCRIPT_SOURCE_PREFIX)) {
      return new DatabaseScriptSource(StringUtils.substringAfter(scriptSourceLocator, GroovyConstant.SCRIPT_SOURCE_PREFIX));
    }

    return new ResourceScriptSource(resourceLoader.getResource(scriptSourceLocator));
  }
}

但是我们也要看看ScriptFactoryPostProcessor帮我们处理的其他工作都是什么：

（1）predictBeanType：是 Spring 中从 BeanDefinition 中提取 Bean 类型的底层 API

（2）我们再来看prepareScriptBeans准备了什么

（3）scriptBeanFactory.registerBeanDefinition，向beanDefinitionMap里put键值对

（4）createScriptedObjectBeanDefinition

（5）Class<?> scriptedType = scriptFactory.getScriptedObjectType(scriptSource);

这句是为了拿到我们具体的实现类，也是我们的基础，它里面就是用GroovyClassLoader去编译我们的groovy脚本内容，并返回了Class<?> scriptClass我们的HelloServiceImpl

（6）ScriptSource scriptSource = getScriptSource(scriptFactoryBeanName, scriptFactory.getScriptSourceLocator());

这里首先去我们下面新增的DatabaseScriptSource里拿到groovy脚本内容，并放进map里，返回DatabaseScriptSource

4、新增DatabaseScriptSource类

package com.maple.database.groovy;

import com.maple.database.groovy.cache.GroovyCache;
import org.springframework.scripting.ScriptSource;
import org.springframework.util.StringUtils;

import java.io.IOException;

/**
 * @author: maple
 * @version: DatabaseScriptSource.java, v 0.1 2020年09月26日 15:37 maple Exp $
 */
public final class DatabaseScriptSource implements ScriptSource {

  /**
   * 脚本名称
   */
  private String scriptName;

  /**
   * 构造函数
   *
   * @param scriptName
   */
  public DatabaseScriptSource(String scriptName) {
    this.scriptName = scriptName;
  }

  @Override
  public String getScriptAsString() throws IOException {

    return GroovyCache.getByName(scriptName).getGroovyContent();
  }

  @Override
  public boolean isModified() {
    return false;
  }

  @Override
  public String suggestedClassName() {
    return StringUtils.stripFilenameExtension(this.scriptName);
  }
}

5、把我们的CustomerScriptFactoryPostProcessor放进Spring的List<BeanPostProcessor>中

这样的话，我们就能从Spring容器中获取helloService的bean实例了，测试：

package com.maple.database.controller;

import com.maple.database.groovy.HelloService;
import com.maple.database.groovy.SpringContextUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author: maple
 * @version: GroovyController.java, v 0.1 2020年09月26日 17:18 maple Exp $
 */
@RestController
public class NewGroovyController {

  @GetMapping("/newGroovyTest")
  private String newGroovyTest() {

    HelloService helloService = SpringContextUtils.getBean("helloService");

    String hello = helloService.sayHello("maple");

    System.out.println(hello);

    return hello;
  }
}

 总结：

优点：项目初始化的时候，就把DB里的groovy脚本读取到，放进本次缓存里，并交给Spring管理，减少与DB的交互次数；没有硬编码，扩展性更好。

缺点：当DB里的groovy脚本文件需要修改时，我们改完之后不能立即生效，需要重启工程或者刷新本次缓存，再次放进Spring容器里才行

附上核心处理类：GroovyDynamicLoader

package com.maple.database.manage;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.maple.database.entity.GroovyScript;
import com.maple.database.groovy.cache.GroovyCache;
import com.maple.database.groovy.cache.GroovyInfo;
import com.maple.database.service.GroovyScriptService;
import groovy.lang.GroovyClassLoader;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.xml.ResourceEntityResolver;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;

import javax.annotation.Resource;
import java.util.List;
import java.util.stream.Collectors;

/**
 * @author: maple
 * @version: GroovyDynamicLoader.java, v 0.1 2020年09月26日 20:00 maple Exp $
 */
@Configuration
public class GroovyDynamicLoader implements ApplicationContextAware, InitializingBean {

  private ConfigurableApplicationContext applicationContext;

  @Override
  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
    this.applicationContext = (ConfigurableApplicationContext) applicationContext;
  }

  @Resource
  private GroovyScriptService groovyScriptService;

  private static final GroovyClassLoader groovyClassLoader = new GroovyClassLoader(GroovyDynamicLoader.class.getClassLoader());

  @Override
  public void afterPropertiesSet() throws Exception {
    init();
  }

  private void init() {

    List<GroovyScript> groovyScripts = groovyScriptService.list(new QueryWrapper<GroovyScript>().eq("status", "ENABLE"));

    List<GroovyInfo> groovyInfos = groovyScripts.stream().map(groovyScript -> {
      GroovyInfo groovyInfo = new GroovyInfo();
      groovyInfo.setClassName(groovyScript.getScriptName());
      groovyInfo.setGroovyContent(groovyScript.getScriptContent());
      return groovyInfo;
    }).collect(Collectors.toList());

    if (CollectionUtils.isEmpty(groovyInfos)) {
      return;
    }

    ConfigurationXMLWriter config = new ConfigurationXMLWriter();

    addConfiguration(config, groovyInfos);

    GroovyCache.put2map(groovyInfos);

    loadBeanDefinitions(config);
  }

  private void addConfiguration(ConfigurationXMLWriter config, List<GroovyInfo> groovyInfos) {
    for (GroovyInfo groovyInfo : groovyInfos) {
      writeBean(config, groovyInfo);
    }
  }

  private void writeBean(ConfigurationXMLWriter config, GroovyInfo groovyInfo) {

    if (checkSyntax(groovyInfo)) {

      DynamicBean bean = composeDynamicBean(groovyInfo);

      config.write(GroovyConstant.SPRING_TAG, bean);
    }
  }

  private boolean checkSyntax(GroovyInfo groovyInfo) {

    try {
      groovyClassLoader.parseClass(groovyInfo.getGroovyContent());
    } catch (Exception e) {
      return false;
    }

    return true;
  }

  private DynamicBean composeDynamicBean(GroovyInfo groovyInfo) {

    DynamicBean bean = new DynamicBean();

    String scriptName = groovyInfo.getClassName();

    Assert.notNull(scriptName, "parser className cannot be empty!");

    //设置bean的属性，这里只有id和script-source。
    bean.put("id", scriptName);
    bean.put("script-source", GroovyConstant.SCRIPT_SOURCE_PREFIX + scriptName);

    return bean;
  }

  private void loadBeanDefinitions(ConfigurationXMLWriter config) {

    String contextString = config.getContent();

    if (StringUtils.isBlank(contextString)) {
      return;
    }

    XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader((BeanDefinitionRegistry) this.applicationContext.getBeanFactory());
    beanDefinitionReader.setResourceLoader(this.applicationContext);
    beanDefinitionReader.setBeanClassLoader(applicationContext.getClassLoader());
    beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this.applicationContext));
    beanDefinitionReader.loadBeanDefinitions(new InMemoryResource(contextString));

    String[] postProcessorNames = applicationContext.getBeanFactory().getBeanNamesForType(CustomerScriptFactoryPostProcessor.class, true, false);

    for (String postProcessorName : postProcessorNames) {
      applicationContext.getBeanFactory().addBeanPostProcessor((BeanPostProcessor) applicationContext.getBean(postProcessorName));
    }
  }

}

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