SpringBoot 2.x 整合Lombok

Lombok的官方介绍

Project Lombok is a java library that automatically plugs into your editor and build tools, spicing up your java.

Lombok以简单的注解形式来简化java代码，提高开发人员的开发效率

lombok是一个编译级别的插件，它可以在项目编译的时候生成一些代码

1.为IntelliJ IDEA安装插件

file——>settings——>Plugins

安装完后需要重启IntelliJ IDEA

2.添加依赖

org.springframework.boot

spring-boot-starter-web

org.projectlombok

lombok

true

com.alibaba

fastjson

1.2.61

3.使用

常用注解

@Data 注解在类上；提供类所有属性的 getting 和 setting 方法，此外还提供了equals、canEqual、hashCode、toString 方法

@Setter ：注解在属性上；为属性提供 setting 方法

@Setter ：注解在属性上；为属性提供 getting 方法

@Log4j ：注解在类上；为类提供一个属性名为log 的 log4j 日志对象

@NoArgsConstructor ：注解在类上；为类提供一个无参的构造方法

@AllArgsConstructor ：注解在类上；为类提供一个全参的构造方法

@Cleanup : 可以关闭流

@Builder ：被注解的类加个构造者模式

@Synchronized ：加个同步锁

@SneakyThrows : 等同于try/catch 捕获异常

@NonNull : 如果给参数加个这个注解参数为null会抛出空指针异常

@Value : 注解和@Data类似，区别在于它会把所有成员变量默认定义为private final修饰，并且不会生成set方法

（1）@Data

@Data 自动生成set/get方法，toString方法，equals方法，hashCode方法，不带参数的构造方法

实体类

package com.abc.plus.entity;

import lombok.Data;

import java.util.Date;

@Data

public class ApiFiles {

private Long id;

private String name;

private Integer size;

private Integer status;

private Date uploadTime;

private String version;

}

测试

package com.abc.plus.controller;

import com.abc.plus.core.Result;

import com.abc.plus.core.SnowFlake;

import com.abc.plus.entity.ApiFiles;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import java.util.Date;

@RestController

public class demoController {

private SnowFlake sn;

@RequestMapping("/test")

public Result test(){

sn = new SnowFlake(1,1);

ApiFiles file = new ApiFiles();

file.setId(sn.nextId());

int r= (int) (Math.random() * 50 + 500);

file.setName("file"+String.valueOf(r));

file.setSize(r);

file.setStatus(1);

Date currentTime = new Date();

file.setUploadTime(currentTime);

return Result.success(200,file);

}

SnowFlake

package com.abc.plus.core;

import com.alibaba.fastjson.JSON;

/**

* Created by Beibei on 19/02/22

* API响应结果

public class Result {

private int code;

private String message;

private T data;

public Result setCode(Integer code) {

this.code = code;

return this;

}

public int getCode() {

return code;

}

public String getMessage() {

return message;

}

public Result setMessage(String message) {

this.message = message;

return this;

}

public T getData() {

return data;

}

public Result setData(T data) {

this.data = data;

return this;

}

@Override

public String toString() {

return JSON.toJSONString(this);

}

public static Result fail(Integer code,T data) {

Result ret = new Result();

ret.setCode(code);

ret.setData(data);

return ret;

}

public static Result failMessage(Integer code,String msg) {

Result ret = new Result();

ret.setCode(code);

ret.setMessage(msg);

return ret;

}

public static Result successMessage(Integer code,String msg) {

Result ret = new Result();

ret.setCode(code);

ret.setMessage(msg);

return ret;

}

public static Result success(Integer code,T data) {

Result ret = new Result();

ret.setCode(code);

ret.setData(data);

return ret;

}

public static Result success(Integer code,T data,String msg) {

Result ret = new Result();

ret.setCode(code);

ret.setData(data);

ret.setMessage(msg);

return ret;

}

View Code

Result

package com.abc.plus.core;

public class SnowFlake {

/**

* 起始的时间戳

private final static long START_STMP = 1480166465631L;

/**

* 每一部分占用的位数

private final static long SEQUENCE_BIT = 12; //序列号占用的位数

private final static long MACHINE_BIT = 5; //机器标识占用的位数

private final static long DATACENTER_BIT = 5;//数据中心占用的位数

/**

* 每一部分的最大值

private final static long MAX_DATACENTER_NUM = -1L ^ (-1L << DATACENTER_BIT);

private final static long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);

private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);

/**

* 每一部分向左的位移

private final static long MACHINE_LEFT = SEQUENCE_BIT;

private final static long DATACENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;

private final static long TIMESTMP_LEFT = DATACENTER_LEFT + DATACENTER_BIT;

private long datacenterId; //数据中心

private long machineId; //机器标识

private long sequence = 0L; //序列号

private long lastStmp = -1L;//上一次时间戳

public SnowFlake(long datacenterId, long machineId) {

if (datacenterId > MAX_DATACENTER_NUM || datacenterId < 0) {

throw new IllegalArgumentException("datacenterId can't be greater than MAX_DATACENTER_NUM or less than 0");

}

if (machineId > MAX_MACHINE_NUM || machineId < 0) {

throw new IllegalArgumentException("machineId can't be greater than MAX_MACHINE_NUM or less than 0");

}

this.datacenterId = datacenterId;

this.machineId = machineId;

}

/**

* 产生下一个ID

* @return

public long nextId() {

long currStmp = getNewstmp();

if (currStmp < lastStmp) {

throw new RuntimeException("Clock moved backwards. Refusing to generate id");

}

if (currStmp == lastStmp) {

//相同毫秒内，序列号自增

sequence = (sequence + 1) & MAX_SEQUENCE;

//同一毫秒的序列数已经达到最大

if (sequence == 0L) {

currStmp = getNextMill();

}

} else {

//不同毫秒内，序列号置为0

sequence = 0L;

}

lastStmp = currStmp;

return (currStmp - START_STMP) << TIMESTMP_LEFT //时间戳部分

| datacenterId << DATACENTER_LEFT //数据中心部分

| machineId << MACHINE_LEFT //机器标识部分

| sequence; //序列号部分

}

private long getNextMill() {

long mill = getNewstmp();

while (mill <= lastStmp) {

mill = getNewstmp();

}

return mill;

}

private long getNewstmp() {

return System.currentTimeMillis();

}

View Code

启动项目

http://localhost:8080/test

返回结果

{

"code": 200,

"message": null,

"data": {

"id": 400317896322060288,

"name": "file507",

"size": 507,

"status": 1,

"uploadTime": "2019-12-06T05:21:29.661+0000",

"version": null

}

（2）@Builder

实体类

package com.abc.plus.entity;

import lombok.Builder;

import lombok.Data;

import java.util.Date;

@Builder

@Data

public class ApiFiles {

private Long id;

private String name;

private Integer size;

private Integer status;

private Date uploadTime;

private String version;

}

测试

package com.abc.plus.controller;

import com.abc.plus.core.Result;

import com.abc.plus.core.SnowFlake;

import com.abc.plus.entity.ApiFiles;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import java.util.Date;

@RestController

public class demoController {

private SnowFlake sn;

@RequestMapping("/test")

public Result test(){

sn = new SnowFlake(1,1);

Long id= sn.nextId();

int r= (int) (Math.random() * 50 + 500);

Date currentTime = new Date();

ApiFiles file = ApiFiles.builder()

.id(id)

.name("file"+String.valueOf(r))

.size(r)

.status(1)

.uploadTime(currentTime)

.build();

return Result.success(200,file);

}

（3）@NonNull

实体类

package com.abc.plus.entity;

import lombok.Builder;

import lombok.Data;

import lombok.NonNull;

import java.util.Date;

@Builder

@Data

public class ApiFiles {

private Long id;

private String name;

private Integer size;

private Integer status;

private Date uploadTime;

@NonNull

private String version;

}

用上边的测试方法测试，没给version赋值，输出结果

{

"timestamp": "2019-12-06T05:40:09.861+0000",

"status": 500,

"error": "Internal Server Error",

"message": "version is marked non-null but is null",

"path": "/test"

}

修改为

　　ApiFiles file = ApiFiles.builder()

.id(id)

.name("file"+String.valueOf(r))

.size(r)

.status(1)

.uploadTime(currentTime)

.version("11")

.build();

结果

{

"code": 200,

"message": null,

"data": {

"id": 400323058746920960,

"name": "file547",

"size": 547,

"status": 1,

"uploadTime": "2019-12-06T05:42:00.479+0000",

"version": "11"

}

还有很多，先写这些了

官网 https://projectlombok.org/

总结：

　　Lombok的优点：

　　　　能通过注解的形式自动生成代码，提高了一定的开发效率；

　　　让代码变得简洁，简化了维护工作

不足：

　　eclipse或IntelliJ IDEA需要安装相应的插件；

　　　　不支持多种参数构造器的重载；

　　　　降低了源代码的可读性和完整性

夸智网

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夸智网

SpringBoot 2.x 整合Lombok

vr 游戏引擎 unity物体沿着手柄射线滑动轨迹旋转

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