Java之String类型的有序Id批量生成器详解

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class IdGenerator {
	private Long currentdbidscount;
	private List<String> ids = new ArrayList<String>();
	private String idpre;
	private String yearstr;
	private String idafter;

	public IdGenerator() {
	}

	public Long getCurrentdbidscount() {
		return currentdbidscount;
	}

	public void setCurrentdbidscount(Long currentdbidscount) {
		this.currentdbidscount = currentdbidscount;
		if (null == this.ids) {
			this.ids = new ArrayList<String>();
		}
	}

	public List<String> getIds() {
		return ids;
	}

	public void setIds(List<String> ids) {
		this.ids = ids;
	}

	public String getIdpre() {
		return idpre;
	}

	public void setIdpre(String idpre) {
		this.idpre = idpre;
	}

	public String getYearstr() {
		return yearstr;
	}

	public void setYearstr(String yearstr) {
		this.yearstr = yearstr;
	}

	public String getIdafter() {
		return idafter;
	}

	public void setIdafter(String idafter) {
		this.idafter = idafter;
	}

	public List<String> initIds(Long ocounts) {
		for (int i = 0; i < ocounts; i++) {
			this.ids.add(getIdPre() + yearStr() + getIdAfter(i));
		}
		return this.ids;
	}

	//
	private String getIdAfter(int addcount) {
		// 默认生成 xx1700001
		//这里是数字部分长度
		int goallength = 5;
		//获取数据库纵向+1次循环(addcount)
		int count = this.currentdbidscount.intValue() + 1 + addcount;
		StringBuilder sBuilder = new StringBuilder("");
		//计算与五位数的差值ֵ
		int length = goallength - new String(count + "").length();
		for (int i = 0; i < length; i++) {
			sBuilder.append("0");
		}
		sBuilder.append(count + "");
		return sBuilder.toString();
	}

	private String getIdPre() {
		// idpre==null?this.idpre="xx":this.idpre=idpre;
		this.idpre = "Id-Hello-";
		return this.idpre;
	}

	private String yearStr() {
		Date currentdate = new Date();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		String yearstr = sdf.format(currentdate).substring(2, 4);
		return yearstr;
	}

	public void clear() {
		this.ids = null;
	}

	@Override
	public String toString() {
		return "IdGenerator [ids=" + ids + "]";
	}
}