Java注解和注解处理器使用方法

原创：转载需注明原创地址 https://www.cnblogs.com/fanerwei222/p/11492274.html

准备材料:

　　实体类: PrintDemo

　　注解类: PrintName

　　注解处理器: AnnotationUtil

　　注解测试类: AnnotationMain

直接上代码:

package annotation;

/**
 * TODO
 * 打印demo
 */
public class PrintDemo {

    @PrintName(print = true)
    private String what;

    @PrintName(print = false)
    private String noWhat;

    @PrintName(print = true)
    private String onThere;

    public String getWhat() {
        return what;
    }

    public void setWhat(String what) {
        this.what = what;
    }

    public String getNoWhat() {
        return noWhat;
    }

    public void setNoWhat(String noWhat) {
        this.noWhat = noWhat;
    }

    public String getOnThere() {
        return onThere;
    }

    public void setOnThere(String onThere) {
        this.onThere = onThere;
    }
}

package annotation;

import java.lang.annotation.*;

/**
 * TODO
 * 打印字段名称
 */
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Target(ElementType.FIELD)
public @interface PrintName {
    boolean print();
}

package annotation;

import java.lang.reflect.Field;

/**
 * TODO
 * 注解处理器工具类
 */
public class AnnotationUtil {
    public static void executeAnnotaPrint(Class<?> clazz){
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields){
            if (field.isAnnotationPresent(PrintName.class) && field.getAnnotation(PrintName.class).print()){
                System.out.println("通过注解打印字段的名称: " + field.getName());
            }
        }
    }
}

package annotation;

/**
 * TODO
 * 注解main测试方法
 */
public class AnnotationMain {
    public static void main(String[] args){
        AnnotationUtil.executeAnnotaPrint(PrintDemo.class);
    }
}

效果如下:

结束