Java生成32位全局唯一id

工具類實現代碼如下：

import java.io.IOException;
import java.net.InetAddress;
import java.security.SecureRandom;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;
 
import org.apache.commons.lang.StringUtils;
 
/** 
 * @ClassName: UniqId 
 * @Description: 生成32位全局唯一id
 */
public class UniqId {
	
	private static UniqId me = new UniqId();
    private String hostAddr;
    private final Random random = new SecureRandom();
    private final UniqTimer timer = new UniqTimer();
    
    private boolean isOutputInfo = false;
    
    private UniqId() {
        try {
            final InetAddress addr = InetAddress.getLocalHost();
 
            hostAddr = addr.getHostAddress();
        }
        catch (final IOException e) {
            System.err.println("[UniqID] Get HostAddr Error"+e);
            hostAddr = String.valueOf(System.currentTimeMillis());
        }
 
        if (null == hostAddr || hostAddr.trim().length() == 0 || "127.0.0.1".equals(hostAddr)) {
            hostAddr = String.valueOf(System.currentTimeMillis());
            
        }
        hostAddr = hostAddr.substring(hostAddr.length()-2).replace(".", "0");
        
        if(isOutputInfo){
        	System.out.println("[UniqID]hostAddr is:" + hostAddr + "----length:"+hostAddr.length());
        }
    }
    
    
    /**
     * 獲取UniqID實例
     * 
     * @return UniqId
     */
    public static UniqId getInstance() {
    	me.isOutputInfo = false;
        return me;
    }
    
    /**
     * 獲取UniqID實例
     * 
     * @return UniqId
     */
	public static UniqId getInstanceWithLog() {
    	me.isOutputInfo = true;
        return me;
    }
 
 
    /**
     * 獲得不會重復的毫秒數
     * 
     * @return 不會重復的時間
     */
    public String getUniqTime() {
    	String time = timer.getCurrentTime();
    	if(isOutputInfo){
    		System.out.println("[UniqID.getUniqTime]" + time +"----length:"+ time.length());
    	}
        return time;
    }
    
    /**
     * 獲得UniqId
     * 
     * @return uniqTime-randomNum-hostAddr-threadId
     */
    public String getUniqID() {
        final StringBuffer sb = new StringBuffer();
        final String t = getUniqTime();
        int randomNumber = random.nextInt(8999999) + 1000000;
        sb.append(t);
        sb.append(hostAddr);
        sb.append(getUniqThreadCode());
        sb.append(randomNumber);
        if (isOutputInfo) {
            System.out.println("[UniqID.randomNumber]" + randomNumber+"----length:"+String.valueOf(randomNumber).length());
            System.out.println("[UniqID.getUniqID]" + sb.toString()+"----length:"+String.valueOf(sb).length());
        }
        return sb.toString();
    }
    
    public String getUniqThreadCode(){
    	String threadCode = StringUtils.left(String.valueOf(Thread.currentThread().hashCode()),9);
    	if (isOutputInfo) {
            System.out.println("[UniqID.getUniqThreadCode]" +threadCode+"----length:"+threadCode.length());
        }
    	return StringUtils.leftPad(threadCode, 9, "0");
    }
    
    /**
     * 實現不重復的時間
     */
    private class UniqTimer {
        private final AtomicLong lastTime = new AtomicLong(System.currentTimeMillis());
 
        public String getCurrentTime() {
        	if(!timestamp2Date(this.lastTime.incrementAndGet()).equals(timestamp2Date(System.currentTimeMillis()))){
        		lastTime.set(System.currentTimeMillis()+random.nextInt(10000));
        	}
        	return timestamp2Datetimes(this.lastTime.incrementAndGet());
        }
    }
    
    /**
	 * 規范化日期，規范成yyyy-MM-dd
	 * @param timestamp
	 * @return
	 */
	public static String timestamp2Date(long timestamp){
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
		return dateFormat.format(new Date(timestamp * 1000));
	}
    
	private static String timestamp2Datetimes(long timestamp){
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
		return dateFormat.format(new Date(timestamp));
	}
    
}


測試代碼如下：

package com.test;
 
public class test {
	public static void main(String[] args) {
		//打印生成過程
		UniqId.getInstanceWithLog().getUniqID();
		
		//建議如下使用
//		String uid = UniqId.getInstance().getUniqID();
//		System.out.println(uid);
//		System.out.println(uid.length());
 
	}
}

　　

上述代碼依賴org.apache.commons.lang.StringUtils，介紹如下兩種依賴的方式：

方式一：Maven項目的依賴

如果你的項目是maven項目，那么請確保項目的pom.xml有如下依賴：

commons-lang 或者commons-lang3