Lombok 的使用

Lombok作为一个奇淫巧技,感觉知道的人还是挺少的
Lombok的一个作用就是不需要写getter和setter方法了,日后修改字段名,也不用修改getter和setter方法,lombok会屏蔽掉这一点

@Data 的使用

@Data 是在class类定义上添加的注解

@Data    
public class Persion{
           private String name;
           private Date birthDay;
          private String habbit;
     }

代码在IDEA里面表现的代码结构为

class 文件反编译之后的结果

package main.java.com.ditmark.lombok;
 import java.util.Date;
 public class Persion {
    private String name;
    private Date birthDay;
    private String hobbit;
   public Persion() {
    }
    public String getName() {
        return this.name;
    }
    public Date getBirthDay() {
        return this.birthDay;
    }
    public String getHobbit() {
        return this.hobbit;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setBirthDay(Date birthDay) {
        this.birthDay = birthDay;
    }
    public void setHobbit(String hobbit) {
        this.hobbit = hobbit;
    }
    public boolean equals(Object o) {
        if(o == this) {
            return true;
        } else if(!(o instanceof Persion)) {
            return false;
        } else {
            Persion other = (Persion)o;
            if(!other.canEqual(this)) {
                return false;
            } else {
                label47: {
                    Object this$name = this.getName();
                    Object other$name = other.getName();
                    if(this$name == null) {
                        if(other$name == null) {
                            break label47;
                        }
                    } else if(this$name.equals(other$name)) {
                        break label47;
                    }
                    return false;
                }
                Object this$birthDay = this.getBirthDay();
                Object other$birthDay = other.getBirthDay();
                if(this$birthDay == null) {
                    if(other$birthDay != null) {
                        return false;
                    }
                } else if(!this$birthDay.equals(other$birthDay)) {
                    return false;
                }
                Object this$hobbit = this.getHobbit();
                Object other$hobbit = other.getHobbit();
                if(this$hobbit == null) {
                    if(other$hobbit != null) {
                        return false;
                    }
                } else if(!this$hobbit.equals(other$hobbit)) {
                    return false;
                }
                return true;
            }
        }
    }
    protected boolean canEqual(Object other) {
        return other instanceof Persion;
    }
    public int hashCode() {
        int PRIME = true;
        int result = 1;
        Object $name = this.getName();
        int result = result * 59 + ($name == null?43:$name.hashCode());
        Object $birthDay = this.getBirthDay();
        result = result * 59 + ($birthDay == null?43:$birthDay.hashCode());
        Object $hobbit = this.getHobbit();
        result = result * 59 + ($hobbit == null?43:$hobbit.hashCode());
        return result;
    }
    public String toString() {
        return "Persion(name=" + this.getName() + ", birthDay=" + this.getBirthDay() + ", hobbit=" + this.getHobbit() + ")";
    }
}

Lombok还可以在循环的时候使用,强制循环中使用final 类型的对象,避免对象在循环过程中进行误操作.

public static void main(String args){
        val list= new ArrayList<String>();
        list.add("A");
        list.add("B");
        list.add("C");
        list.add("D");
    for(val str: list){
            System.out.println(str);
        }
        val map = new HashMap<String,String>();
        for(val key : map.keySet()){
            System.out.println(key);
        }
        for(val entry : map.entrySet()){
            System.out.println(entry.getKey());
        }
    }

class 反编译之后,并没有发现final 可怕…也许是版本的差异?使用的版本为lombok 1.16.16

public static void main(String args) {
        ArrayList<String> list = new ArrayList();
        list.add("A");
        list.add("B");
        list.add("C");
        list.add("D");
        Iterator var2 = list.iterator();
        while(var2.hasNext()) {
            String str = (String)var2.next();
            System.out.println(str);
        }
        HashMap<String, String> map = new HashMap();
        Iterator var6 = map.keySet().iterator();
        while(var6.hasNext()) {
            String key = (String)var6.next();
            System.out.println(key);
        }
        var6 = map.entrySet().iterator();
        while(var6.hasNext()) {
            Entry<String, String> entry = (Entry)var6.next();
            System.out.println((String)entry.getKey());
        }
    }

Lombok在流资源的开启和关闭也可以使用,避免写一堆close catch代码