文章目錄
-
- 一、搭建父工程
-
- 1.1 選擇菜單file-new project ,彈出視窗中左側菜單選擇Maven ,點選next按鈕
- 1.2 填寫GroupId和ArtifacetId ,點選next按鈕
- 1.3 點選Finish 完成
- 1.4 删除src檔案夾
- 1.5 修改pom.xml 添加以下配置
- 1.6 當IDEA右下角彈出提示 ,點選Enable Auto-Import 自動導入依賴
- 二、搭建公共子子產品tensquare_common
-
- 2.1 右鍵點選工程,彈出菜單選擇New-Module 彈出視窗選擇Maven ,點選next按鈕
- 2.2 點選finish
- 2.3 建立傳回結果實體類
-
- 2.3.1 建立entity包,包下建立類Result
- 2.4 建立類PageResult
- 2.5 建立傳回碼定義類
- 2.6 分布式ID生成器
- 三、小結
一、搭建父工程
1.1 選擇菜單file-new project ,彈出視窗中左側菜單選擇Maven ,點選next按鈕
1.2 填寫GroupId和ArtifacetId ,點選next按鈕
1.3 點選Finish 完成
1.4 删除src檔案夾
1.5 修改pom.xml 添加以下配置
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.tensquare</groupId>
<artifactId>tensquare_parent</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>tensquare_parent</name>
<description>十次方項目-小洋人最happy</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.1.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>
1.6 當IDEA右下角彈出提示 ,點選Enable Auto-Import 自動導入依賴
至此,父工程搭建完成。
二、搭建公共子子產品tensquare_common
2.1 右鍵點選工程,彈出菜單選擇New-Module 彈出視窗選擇Maven ,點選next按鈕
2.2 點選finish
2.3 建立傳回結果實體類
2.3.1 建立entity包,包下建立類Result
該類用于控制器類傳回結果。
代碼如下:
package entity;
/**
* Created by me on 2019/6/25.
*/
public class Result<T> {
private boolean flag;
private Integer code;
private String message;
private Object data;
public Result(boolean flag, Integer code, String message, Object data) {
this.flag = flag;
this.code = code;
this.message = message;
this.data = data;
}
public Result(boolean flag, Integer code, String message) {
this.flag = flag;
this.code = code;
this.message = message;
}
public Result() {
}
public boolean isFlag() {
return flag;
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
2.4 建立類PageResult
該類用于傳回分頁結果。
代碼如下:
package entity;
import java.util.List;
/**
* Created by me on 2019/6/25.
*/
public class PageResult<T> {
private long total;
private List<T> rows;
public PageResult(long total, List<T> rows) {
this.total = total;
this.rows = rows;
}
public long getTotal() {
return total;
}
public void setTotal(long total) {
this.total = total;
}
public List<T> getRows() {
return rows;
}
public void setRows(List<T> rows) {
this.rows = rows;
}
}
2.5 建立傳回碼定義類
将錯誤碼統一歸類管理。
代碼如下:
package entity;
/**
* Created by me on 2019/6/25.
*/
public class StatusCode {
public static final int OK = 20000;// 成功
public static final int ERROR = 20001;// 失敗
public static final int LOGIN_ERROR = 20002;// 使用者名或密碼錯誤
public static final int ACCESS_ERROR = 20003;// 權限不在不
public static final int REMOTE_ERROR = 20004;// 遠端調用失敗
public static final int REP_ERROR = 20005;// 重複操作
}
2.6 分布式ID生成器
由于我們的資料庫在生産環境中要分片部署(MyCat),是以我們不能使用資料庫本身的自增功能來産生主鍵值,隻能由程式來生成唯一的主鍵值。
我們采用的是開源的 twitter的 snowflake (雪花)算法。
預設情況下41bit的時間戳可以支援該算法使用到2082年,10bit的工作機器id可以 支援1024台機器,序列号支援1毫秒産生4096個自增序列id .
SnowFlake的優點是,整體上按照時間自增排序,并且整個分布式系統内不會産生ID碰撞(由資料中心ID和機器ID 作區分),并且效率較高。
經測試,SnowFlake每秒能夠産生26萬ID左右
在
tensquare_common
工程中建立
util
包,建立
IdWorker.java
檔案(分布式ID生成器),将如下代碼拷入即可。
package util;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
/**
* <p>名稱:IdWorker.java</p>
* <p>描述:分布式自增長ID</p>
* <pre>
* Twitter的 Snowflake JAVA實作方案
* </pre>
* 核心代碼為其IdWorker這個類實作,其原理結構如下,我分别用一個0表示一位,用—分割開部分的作用:
* 1||0---0000000000 0000000000 0000000000 0000000000 0 --- 00000 ---00000 ---000000000000
* 在上面的字元串中,第一位為未使用(實際上也可作為long的符号位),接下來的41位為毫秒級時間,
* 然後5位datacenter辨別位,5位機器ID(并不算辨別符,實際是為線程辨別),
* 然後12位該毫秒内的目前毫秒内的計數,加起來剛好64位,為一個Long型。
* 這樣的好處是,整體上按照時間自增排序,并且整個分布式系統内不會産生ID碰撞(由datacenter和機器ID作區分),
* 并且效率較高,經測試,snowflake每秒能夠産生26萬ID左右,完全滿足需要。
* <p>
* 64位ID (42(毫秒)+5(機器ID)+5(業務編碼)+12(重複累加))
*
* @author Polim
*/
public class IdWorker {
// 時間起始标記點,作為基準,一般取系統的最近時間(一旦确定不能變動)
private final static long twepoch = 1288834974657L;
// 機器辨別位數
private final static long workerIdBits = 5L;
// 資料中心辨別位數
private final static long datacenterIdBits = 5L;
// 機器ID最大值
private final static long maxWorkerId = -1L ^ (-1L << workerIdBits);
// 資料中心ID最大值
private final static long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
// 毫秒内自增位
private final static long sequenceBits = 12L;
// 機器ID偏左移12位
private final static long workerIdShift = sequenceBits;
// 資料中心ID左移17位
private final static long datacenterIdShift = sequenceBits + workerIdBits;
// 時間毫秒左移22位
private final static long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
private final static long sequenceMask = -1L ^ (-1L << sequenceBits);
/* 上次生産id時間戳 */
private static long lastTimestamp = -1L;
// 0,并發控制
private long sequence = 0L;
private final long workerId;
// 資料辨別id部分
private final long datacenterId;
public IdWorker(){
this.datacenterId = getDatacenterId(maxDatacenterId);
this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);
}
/**
* @param workerId
* 工作機器ID
* @param datacenterId
* 序列号
*/
public IdWorker(long workerId, long datacenterId) {
if (workerId > maxWorkerId || workerId < 0) {
throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));
}
if (datacenterId > maxDatacenterId || datacenterId < 0) {
throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));
}
this.workerId = workerId;
this.datacenterId = datacenterId;
}
/**
* 擷取下一個ID
*
* @return
*/
public synchronized long nextId() {
long timestamp = timeGen();
if (timestamp < lastTimestamp) {
throw new RuntimeException(String.format("Clock moved backwards. Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
}
if (lastTimestamp == timestamp) {
// 目前毫秒内,則+1
sequence = (sequence + 1) & sequenceMask;
if (sequence == 0) {
// 目前毫秒内計數滿了,則等待下一秒
timestamp = tilNextMillis(lastTimestamp);
}
} else {
sequence = 0L;
}
lastTimestamp = timestamp;
// ID偏移組合生成最終的ID,并傳回ID
long nextId = ((timestamp - twepoch) << timestampLeftShift)
| (datacenterId << datacenterIdShift)
| (workerId << workerIdShift) | sequence;
return nextId;
}
private long tilNextMillis(final long lastTimestamp) {
long timestamp = this.timeGen();
while (timestamp <= lastTimestamp) {
timestamp = this.timeGen();
}
return timestamp;
}
private long timeGen() {
return System.currentTimeMillis();
}
/**
* <p>
* 擷取 maxWorkerId
* </p>
*/
protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {
StringBuffer mpid = new StringBuffer();
mpid.append(datacenterId);
String name = ManagementFactory.getRuntimeMXBean().getName();
if (!name.isEmpty()) {
/*
* GET jvmPid
*/
mpid.append(name.split("@")[0]);
}
/*
* MAC + PID 的 hashcode 擷取16個低位
*/
return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);
}
/**
* <p>
* 資料辨別id部分
* </p>
*/
protected static long getDatacenterId(long maxDatacenterId) {
long id = 0L;
try {
InetAddress ip = InetAddress.getLocalHost();
NetworkInterface network = NetworkInterface.getByInetAddress(ip);
if (network == null) {
id = 1L;
} else {
byte[] mac = network.getHardwareAddress();
id = ((0x000000FF & (long) mac[mac.length - 1])
| (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;
id = id % (maxDatacenterId + 1);
}
} catch (Exception e) {
System.out.println(" getDatacenterId: " + e.getMessage());
}
return id;
}
}
至此,公共子產品common搭建完畢。
三、小結
通過該篇文章,主要學會了:
- 搭建父工程
- 搭建公共子產品,建立通用傳回類
- 分布式ID生成器(snowflake算法)