Serialization, listening, custom annotation

1. Separate use jdk,protobuf,json Serialization deserialization of an object of a specific class

// jdk
//  serialize 
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("E:\\Person.txt"));
    Person person = new Person();
    // Call the method that writes the object writeObject
    oos.writeObject(person);
	oos.flush();
    oos.close();

//  Deserialization 
FileInputStream fis = new FileInputStream("E:\\Person.txt");
ObjectInputStream ois = new ObjectInputStream(fis);
Object o = ois.readObject();
System.out.println(o);
fis.close();
ois.close();
//protobuf
//  serialize 
DataInfo.Student student = DataInfo.Student.newBuilder()
                .setName("xxxx").setAge(100).setAddress(" China ").build();
byte[] bytes = student.toByteArray();                
               
//  Deserialization 
DataInfo.Student student1 = DataInfo.Student.parseFrom(bytes);

//  take Java Object serialization to Json character string  
 String objectToJson = JSON.toJSONString(initUser());  
 System.out.println(objectToJson);  
 //  take Json Deserialize string to Java object  
 User user = JSON.parseObject(objectToJson, User.class);  
 System.out.println(user);  

2. be based on guava Event bus in the framework @Listener Annotations realize the monitoring of specific events

@Service
public class EventListener {
    

    @org.springframework.context.event.EventListener
    public void onSynMsgEvent(CreateMsgEvent event){
    
        try {
    
            Thread.sleep(1000);
        } catch (InterruptedException e) {
    
            e.printStackTrace();
        }
    }

    @Async
    @org.springframework.context.event.EventListener
    public void onAsynMsgEvent(CreateMsgEvent event){
    
        try {
    
            Thread.sleep(1000);
        } catch (InterruptedException e) {
    
            e.printStackTrace();
        }
    }
}

3. Recognize when the application starts spring bean The instance is marked with @Counter Methods

import java.lang.annotation.*;

@Target({
    ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Counter{
    
    boolean value() default true;
}

public class BeanFactory {
    

    /** *  Task a ： Read parsing xml, Instantiate objects by reflection and store them for use （map aggregate ） *  Task 2 ： It provides an interface for getting instance objects （ according to id obtain ） */
    private static Map<String, Object> map = new HashMap<>();  //  Store the object 

    static {
    
        try {
    
            // Task a 、 Scanning package , Instantiate objects by reflection and store them for use （map aggregate ）

            // Through reflection technology , Scan the package and get a collection of reflection objects 
            Reflections edus = new Reflections("com.lagou.edu");
            Set<Class<?>> clazzs = edus.getTypesAnnotatedWith(Counter.class);
            // Traversing the collection of objects 
            for (Class<?> clazz : clazzs) {
    
                //  Get the instanced object 
                Object object = clazz.getDeclaredConstructor().newInstance();
                Counter service = clazz.getAnnotation(Counter.class);

                // Judge Service Whether there is a custom object on the annotation ID
                if (StringUtils.isEmpty(service.value())) {
    
                    // because getName Get the fully qualified class name , So we need to split and remove the previous package name 
                    String[] names = clazz.getName().split("\\.");
                    map.put(names[names.length - 1], object);
                } else {
    
                    map.put(service.value(), object);
                }
            }
       } catch (Exception e) {
    
            e.printStackTrace();
        }
    }
    }