Three ways to obtain reflection in Java and its application

1. Three ways to obtain reflections

1.1 throughClass.classTo obtain

@Data
public class ModelA {

    private String name;

    private Integer age;

    private LocalDateTime dateTime;

}
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 Class<ModelA> aClass = ModelA.class;
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1.2 throughobj.getClass()Way to obtain

 ModelA modelA = new ModelA();
 Class<? extends ModelA> aClass1 = modelA.getClass();
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1.3 throughClass.forName()Way to obtain

Class<? > aClass1 = Class.forName("com.demo.model.ModelA");
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By Class. Class.forname () way to get reflection need to capture the Java lang. ClassNotFoundException

2. Obtain all properties of the object including the parent class through reflection

public List<Field> getAllField(Class
        aClass) {
        if (aClass == null) {
            return new ArrayList<>();
        }
        List<Field> fieldList = new ArrayList<>();
        while(aClass ! =null) {
            fieldList.addAll(Arrays.asList(aClass.getDeclaredFields()));
            aClass = aClass.getSuperclass();
        }
        return fieldList;
    }
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3. Obtain object property information through reflection

public static void printFieldInfo(Field field) {
    // Attribute name
    String name = field.getName();
    // Attribute type fully qualified class name (base type returns base type such as int)
    String fieldTypeName = field.getGenericType().getTypeName();
    // Get all the annotations decorated on the property
    Annotation[] annotationArray = field.getDeclaredAnnotations();
    // Get the @value annotation on the attribute
    Value declaredAnnotation = field.getDeclaredAnnotation(Value.class);
}
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4. Obtain method information through reflection

public static void printMethodInfo(Method method) {
    for (Parameter parameter : method.getParameters()) {
        // The name of the argument is arg0
        String name = parameter.getName();
        // Fully qualified class name (base type returns base type like int)
        String parameterType = parameter.getParameterizedType().getTypeName();
        // Get all the annotations decorated on the parameter
        Annotation[] annotationArray = parameter.getDeclaredAnnotations();
        // Get the @requestParam annotation on the parameter
        RequestParam requestParam = parameter.getDeclaredAnnotation(RequestParam.class);
    }

    // The return type of the method
    String methodReturnTypeName = method.getGenericReturnType().getTypeName();
    // Get all the annotations decorated on the method
    Annotation[] annotationArray = method.getDeclaredAnnotations();
    // Get the @override annotation on the method
    Override override = method.getDeclaredAnnotation(Override.class);
}
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