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Spring Boot + 领域驱动设计使得微服务越来越火热,而随着微服务越来越多,服务的治理就显得尤为重要。
在我们的业务领域开发中,经常会有一些通用性功能搭建,比如;白名单、黑名单、限流、熔断等,为了更好的开发业务功能,我们需要将非业务功能的通用逻辑提取出来开发出通用组件,以便于业务系统使用。而不至于Copy来Copy去,让代码乱的得加薪才能修改的地步!
通常一个中间件开发会需要用到;自定义xml配置、自定义Annotation注解、动态代理、反射调用、字节码编程(javaassist、ASM等),以及一些动态注册服务中心和功能逻辑开发等。本案例会使用Spring Boot开发方式定义自己的starter。
通过我们使用一个公用的starter的时候,只需要将相应的依赖添加的Maven的配置文件当中即可,免去了自己需要引用很多依赖类,并且SpringBoot会自动进行类的自动配置。而我们自己开发一个starter也需要做相应的处理;
SpringBoot 在启动时会去依赖的starter包中寻找 resources/META-INF/spring.factories 文件,然后根据文件中配置的Jar包去扫描项目所依赖的Jar包,这类似于 Java 的 SPI 机制。
SPI 全称 Service Provider Interface,是Java提供的一套用来被第三方实现或者扩展的API,它可以用来启用框架扩展和替换组件。
根据 spring.factories配置加载AutoConfigure类。
根据 @Conditional注解的条件,进行自动配置并将Bean注入Spring Context 上下文当中。也可以使用@ImportAutoConfiguration({MyServiceAutoConfiguration.class}) 指定自动配置哪些类。
日常使用的Spring官方的Starter一般采取spring-boot-starter-{name} 的命名方式,如 spring-boot-starter-web 。而非官方的Starter,官方建议 artifactId 命名应遵循{name}-spring-boot-starter 的格式。 例如:door-spring-boot-starter 。
中间件工程:door-spring-boot-starter
door-spring-boot-starter
└── src
├── main
│ ├── java
│ │ └── org.itstack.door
│ │ ├── annotation
│ │ │└── DoDoor.java
│ │ ├── config
│ │ │├── StarterAutoConfigure.java
│ │ │├── StarterService.java
│ │ │└── StarterServiceProperties.java
│ │ └── DoJoinPoint.java
│ └── resources
│ └── META_INF
│ └── spring.factories
└── test
└── java
└── org.itstack.demo.test
└── ApiTest.java
演示部分重点代码块,完整代码下载关注公众号;bugstack虫洞栈,回复:中间件开发
door/annotation/DoDoor.java & 自定义注解
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface DoDoor {
String key() default "";
String returnJson() default "";
}
config/StarterAutoConfigure.java & 配置信息装配
@Configuration
@ConditionalOnClass(StarterService.class)
@EnableConfigurationProperties(StarterServiceProperties.class)
public class StarterAutoConfigure {
@Autowired
private StarterServiceProperties properties;
@Bean
@ConditionalOnMissingBean
@ConditionalOnProperty(prefix = "itstack.door", value = "enabled", havingValue = "true")
StarterService starterService() {
return new StarterService(properties.getUserStr());
}
}
config/StarterServiceProperties.java & 属性配置
@ConfigurationProperties("itstack.door")
public class StarterServiceProperties {
private String userStr;
public String getUserStr() {
return userStr;
}
public void setUserStr(String userStr) {
this.userStr = userStr;
}
}
DoJoinPoint.java & 自定义切面
@Aspect
@Component
public class DoJoinPoint {
private Logger logger = LoggerFactory.getLogger(DoJoinPoint.class);
@Autowired
private StarterService starterService;
@Pointcut("@annotation(org.itstack.door.annotation.DoDoor)")
public void aopPoint() {
}
@Around("aopPoint()")
public Object doRouter(ProceedingJoinPoint jp) throws Throwable {
//获取内容
Method method = getMethod(jp);
DoDoor door = method.getAnnotation(DoDoor.class);
//获取字段值
String keyValue = getFiledValue(door.key(), jp.getArgs());
logger.info("itstack door handler method:{} value:{}", method.getName(), keyValue);
if (null == keyValue || "".equals(keyValue)) return jp.proceed();
//配置内容
String[] split = starterService.split(",");
//白名单过滤
for (String str : split) {
if (keyValue.equals(str)) {
return jp.proceed();
}
}
//拦截
return returnObject(door, method);
}
private Method getMethod(JoinPoint jp) throws NoSuchMethodException {
Signature sig = jp.getSignature();
MethodSignature methodSignature = (MethodSignature) sig;
return getClass(jp).getMethod(methodSignature.getName(), methodSignature.getParameterTypes());
}
private Class<? extends Object> getClass(JoinPoint jp) throws NoSuchMethodException {
return jp.getTarget().getClass();
}
//返回对象
private Object returnObject(DoDoor doGate, Method method) throws IllegalAccessException, InstantiationException {
Class<?> returnType = method.getReturnType();
String returnJson = doGate.returnJson();
if ("".equals(returnJson)) {
return returnType.newInstance();
}
return JSON.parseObject(returnJson, returnType);
}
//获取属性值
private String getFiledValue(String filed, Object[] args) {
String filedValue = null;
for (Object arg : args) {
try {
if (null == filedValue || "".equals(filedValue)) {
filedValue = BeanUtils.getProperty(arg, filed);
} else {
break;
}
} catch (Exception e) {
if (args.length == 1) {
return args[0].toString();
}
}
}
return filedValue;
}
}
pom.xml & 部分配置内容
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<archive>
<addMavenDescriptor>false</addMavenDescriptor>
<index>true</index>
<manifest>
<addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
</manifest>
<manifestEntries>
<Implementation-Build>${maven.build.timestamp}</Implementation-Build>
</manifestEntries>
</archive>
</configuration>
</plugin>
spring.factories & spring入口配置
org.springframework.boot.autoconfigure.EnableAutoConfiguration=org.itstack.door.config.StarterAutoConfigure
测试工程:itstack-demo-springboot-helloworld
itstack-demo-springboot-helloworld
└── src
├── main
│ ├── java
│ │ └── org.itstack.demo
│ │ ├── domain
│ │ │└── UserInfo.java
│ │ ├── web
│ │ │└── HelloWorldController.java
│ │ └── HelloWorldApplication.java
│ └── resources
│ └── application.yml
└── test
└── java
└── org.itstack.demo.test
└── ApiTest.java
演示部分重点代码块,完整代码下载关注公众号;bugstack虫洞栈,回复:中间件开发
pom.xml & 引入中间件配置
<dependency>
<groupId>org.itatack.demo</groupId>
<artifactId>door-spring-boot-starter</artifactId>
<version>1.0.1-SNAPSHOT</version>
</dependency>
web/HelloWorldController.java & 配置白名单拦截服务
@RestController
public class HelloWorldController {
@DoDoor(key = "userId", returnJson = "{\"code\":\"1111\",\"info\":\"非白名单可访问用户拦截!\"}")
@RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET)
public UserInfo queryUserInfo(@RequestParam String userId) {
return new UserInfo("虫虫:" + userId, 19, "天津市南开区旮旯胡同100号");
}
}
application.yml & Yml配置
server:
port: 8080
spring:
application:
name: itstack-demo-springboot-helloworld
# 自定义中间件配置
itstack:
door:
enabled: true
userStr: 1001,aaaa,ccc #白名单用户ID,多个逗号隔开
白名单用户:http://localhost:8080/api/queryUserInfo?userId=1001
{"code":"0000","info":"success","name":"虫虫:1001","age":19,"address":"天津市南开区旮旯胡同100号"}
非名单用户:http://localhost:8080/api/queryUserInfo?userId=小团团
{"code":"1111","info":"非白名单可访问用户拦截!","name":null,"age":null,"address":null}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.1.2.RELEASE)
2019-12-03 23:25:40.128 INFO 177110 --- [ main] org.itstack.demo.HelloWorldApplication : Starting HelloWorldApplication on FUZHENGWEI with PID 177110 (E:\itstack\github.com\itstack-demo-springboot-helloworld\target\classes started by fuzhengwei in E:\itstack\github.com\itstack-demo-springboot-helloworld)
2019-12-03 23:25:40.133 INFO 177110 --- [ main] org.itstack.demo.HelloWorldApplication : No active profile set, falling back to default profiles: default
2019-12-03 23:25:42.446 INFO 177110 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-12-03 23:25:42.471 INFO 177110 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-12-03 23:25:42.471 INFO 177110 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.14]
2019-12-03 23:25:42.483 INFO 177110 --- [ main] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in
2019-12-03 23:25:42.611 INFO 177110 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-12-03 23:25:42.612 INFO 177110 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2421 ms
2019-12-03 23:25:43.063 INFO 177110 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2019-12-03 23:25:43.317 INFO 177110 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2019-12-03 23:25:43.320 INFO 177110 --- [ main] org.itstack.demo.HelloWorldApplication : Started HelloWorldApplication in 3.719 seconds (JVM running for 4.294)
2019-12-03 23:26:56.107 INFO 177110 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-12-03 23:26:56.107 INFO 177110 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2019-12-03 23:26:56.113 INFO 177110 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 6 ms
2019-12-03 23:26:56.171 INFO 177110 --- [nio-8080-exec-1] org.itstack.door.DoJoinPoint : itstack door handler method:queryUserInfo value:1001
2019-12-03 23:27:04.090 INFO 177110 --- [nio-8080-exec-3] org.itstack.door.DoJoinPoint : itstack door handler method:queryUserInfo value:小团团
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