Springboot中动态语言groovy介绍-Java开发

Apache的Groovy是Java平台上设计的面向对象编程语言，这门动态语言拥有类似Python、Ruby和Smalltalk中的一些特性，可以作为Java平台的脚本语言使用，这篇文章主要介绍了springboot中如何使用groovy,需要的朋友可以参考下

Groovy

Groovy是一种基于Java的语法的基于JVM的编程语言。Groovy支持动态输入，闭包，元编程，运算符重载等等语法。除此之外，Groovy还提供了许多类似脚本语言的功能，比如，多行字符串，字符串插值，优雅的循环结构和简单的属性访问。另外，结尾分号是可选的。而这些都有足够的理帮助开发人员为了提高开发效率。

换句话说，Groovy就是一种继承了动态语言的优良特性并运行在JVM上的编程语言。由于Groovy的语法非常接近Java，所以Java开发人员很容易开始使用Groovy。 Spring Boot应用中也支持使用Groovy编程语言进行开发。

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

pom

<!-- groovy -->
<dependency>
    <artifactId>groovy</artifactId>
    <groupId>org.codehaus.groovy</groupId>
    <version>2.5.8</version>
    <scope>compile</scope>
</dependency>

ResourceScriptSource

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        ConfigurableApplicationContext run = SpringApplication.run(DemoApplication.class, args);
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring-groovy.xml");
        GroovyService bean = context.getBean(GroovyService.class);
        String sayHello = bean.sayHello();
        System.out.println(sayHello);
    }
}

public interface GroovyService {
    String sayHello();
}

spring-groovy.xml

<?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.example.demo.groovy.GroovyService
            class HelloServiceImpl implements GroovyService {
                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>

DatabaseScriptSource

方法一：

实时读取DB里的groovy脚本文件

利用GroovyClassLoader去编译脚本文件

把class对象注入成Spring bean

反射调用脚本的方法

CREATE TABLE `groovy_script` (
  `id` bigint 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=2 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='groovy script';

INSERT INTO book_shop2.groovy_script
(id, script_name, script_content, status, extend_info, created_time, modified_time)
VALUES(1, 'groovyService', 'import com.example.demo.groovy.GroovyService
            class HelloServiceImpl implements GroovyService {
				@Override
				String sayHello() {
					return "sayHello";
				}
                @Override
                String sayHello(String name) {
                    return "Hello " + name + ". Welcome to static script in Groovy.";
                }
            }', 'ENABLE', NULL, '2020-09-26 17:16:36.477818000', '2022-09-04 22:54:51.421959000');

@RestController
public class GroovyController {
    @Autowired
    GroovyScriptMapper groovyScriptMapper;
    @GetMapping("/aaaa")
    private String groovyTest() throws IllegalAccessException, InstantiationException, InvocationTargetException, NoSuchMethodException {
        GroovyScript groovyScript = this.groovyScriptMapper.getOne(1L);
        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);
        String aaaaaaa = (String) method.invoke(o, "aaaaaaa");
        System.out.println(aaaaaaa);
        return aaaaaaa;
    }
}
/*
import com.example.demo.groovy.GroovyService
            class HelloServiceImpl implements GroovyService {
				@Override
				String sayHello() {
					return "sayHello";
				}
                @Override
                String sayHello(String name) {
                    return "Hello " + name + ". Welcome to static script in Groovy.";
                }
            }
Hello aaaaaaa. Welcome to static script in Groovy.
*/

public interface GroovyScriptMapper extends BaseMapper<GroovyScript> {
    @Select({"select script_content from groovy_script where id = #{id}"})
    @Result(column = "script_content", property = "scriptContent")
    GroovyScript getOne(Long id);
}

@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);
    }
}

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