把java接口写在数据库里（groovy）
业务复杂多变？那把接口写在数据库里吧，修改随改随用！本文使用了Groovy脚本，不了解的可以自行了解，直接上菜。
- 引入依赖
<dependency>
<groupId>org.codehaus.groovygroupId>
<artifactId>groovy-allartifactId>
<version>2.5.16version>
<type>pomtype>
dependency>
- 创建测试接口
public interface InterfaceA {
/**
* 执行规则
*/
void testMethod();
}
- resource目录下创建.groovy实现上面的接口
@Slf4j
class GroovyInterfaceAImpl implements InterfaceA {
@Override
void testMethod() {
log.info("我是groovy编写的InterfaceA接口实现类中的接口方法")
GroovyScriptService groovyScriptService = SpringUtils.getBean(GroovyScriptService.class)
GroovyScript groovyScript = Optional.ofNullable(groovyScriptService.getOne(new QueryWrapper()
.eq("name", "groovy编写的java接口实现类")
.eq("version", 1))).orElseThrow({ -> new RuntimeException("没有查询到脚本") })
log.info("方法中进行了数据库查询，数据库中的groovy脚本是这个:{}", "\n" + groovyScript.getScript())
}
}
- mysql数据库中建个表groovy_script
5. 将刚才编写的.groovy文件内容存入数据库
@RunWith(SpringRunner.class)
@SpringBootTest
public class GroovyTest {
@Resource
private GroovyScriptService groovyScriptService;
@Test
public void test01() {
GroovyScript groovyScript = new GroovyScript();
groovyScript.setScript("package groovy\n" +
"\n" +
"import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper\n" +
"import com.demo.groovy.entity.GroovyScript\n" +
"import com.demo.groovy.service.GroovyScriptService\n" +
"import com.demo.groovy.service.InterfaceA\n" +
"import com.demo.groovy.util.SpringUtils\n" +
"import groovy.util.logging.Slf4j\n" +
"\n" +
"\n" +
"@Slf4j\n" +
"class GroovyInterfaceAImpl implements InterfaceA {\n" +
"\n" +
" @Override\n" +
" void testMethod() {\n" +
" log.info("我是groovy编写的InterfaceA接口实现类中的接口方法")\n" +
" GroovyScriptService groovyScriptService = SpringUtils.getBean(GroovyScriptService.class)\n" +
" GroovyScript groovyScript = Optional.ofNullable(groovyScriptService.getOne(new QueryWrapper()\n" +
" .eq("name", "groovy编写的java接口实现类")\n" +
" .eq("version", 1))).orElseThrow({ -> new RuntimeException("没有查询到脚本") })\n" +
" log.info("方法中进行了数据库查询，数据库中的groovy脚本是这个:{}", "\n" + groovyScript.getScript())\n" +
" }\n" +
"}");
groovyScript.setVersion(1);
groovyScript.setName("groovy编写的java接口实现类");
groovyScriptService.save(groovyScript);
}
}
- 从数据读取脚本，GroovyClassLoader加载脚本为Class（注意将Class对象进行缓存）
@Service("groovyScriptService")
@Slf4j
public class GroovyScriptServiceImpl extends ServiceImpl<GroovyScriptServiceMapper, GroovyScript> implements GroovyScriptService {
private static final Map<String, Md5Clazz> SCRIPT_MAP = new ConcurrentHashMap<>();
@Override
public Object getInstanceFromDb(String name, Integer version) {
//查询脚本
GroovyScript groovyScript = Optional.ofNullable(baseMapper.selectOne(new QueryWrapper<GroovyScript>()
.eq("name", name)
.eq("version", version))).orElseThrow(() -> new RuntimeException("没有查询到脚本"));
//将groovy脚本转换为java类对象
Class clazz = getClazz(name + version.toString(), groovyScript.getScript());
Object instance;
try {
instance = clazz.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
return instance;
}
private Class getClazz(String scriptKey, String scriptText) {
String md5Hex = DigestUtil.md5Hex(scriptText);
Md5Clazz md5Script = SCRIPT_MAP.getOrDefault(scriptKey, null);
if (md5Script != null && md5Hex.equals(md5Script.getMd5())) {
log.info("从缓存获取的Clazz");
return md5Script.getClazz();
} else {
CompilerConfiguration config = new CompilerConfiguration();
config.setSourceEncoding("UTF-8");
GroovyClassLoader groovyClassLoader = new GroovyClassLoader(Thread.currentThread().getContextClassLoader(), config);
try {
Class clazz = groovyClassLoader.parseClass(scriptText);
SCRIPT_MAP.put(scriptKey, new Md5Clazz(md5Hex, clazz));
groovyClassLoader.clearCache();
log.info("groovyClassLoader parseClass");
return clazz;
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
try {
groovyClassLoader.close();
} catch (IOException e) {
log.error("close GroovyClassLoader error", e);
}
}
}
}
@Data
private static class Md5Clazz {
private String md5;
private Class clazz;
public Md5Clazz(String md5, Class clazz) {
this.md5 = md5;
this.clazz = clazz;
}
}
}
- 测试
@RestController
@RequestMapping("/test")
@Slf4j
public class GroovyTestController {
@Resource
private GroovyScriptService groovyScriptService;
@GetMapping("")
public String testGroovy() {
InterfaceA interfaceA = (InterfaceA) groovyScriptService.getInstanceFromDb("groovy编写的java接口实现类", 1);
interfaceA.testMethod();
return "ok";
}
}
- 接口方法被执行。想要修改接口的话在idea里面把groovy文件编辑好更新到数据库就行了，即时生效。
本文简单给大家提供一种思路，希望能对大家有所帮助，如有不当之处还请大家指正。本人之前在项目中用的比较多的是Groovyshell，执行的是一些代码片段，而GroovyClassLoader则可以加载整个脚本为Class，Groovy对于java开发者来说还是比较友好的，上手容易。
作者：爸爸给你买GTI
来源：juejin.cn/post/7397013935106048051
来源：juejin.cn/post/7397013935106048051
