package com.jiaoyiping.berkeleydb;import com.sleepycat.je.*;import com.sleepycat.utilint.StringUtils;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.UnsupportedEncodingException;/** * Created with IntelliJ IDEA. * User: 焦一平 * Date: 14-7-9 * Time: 下午1:27 * To change this template use File | Settings | File Templates. * 1.直接存key和value * 2.存储key和value组合成的对象(未使用) */public class SerialNumberGenerator {    Logger logger = LoggerFactory.getLogger(SerialNumberGenerator.class);    private static int MAX_VALUE = http://www.mamicode.com/9999;    private static int MIN_VALUE = http://www.mamicode.com/1;    /**     * 对于任何的请求，总是先取出当前的值返回，然后再将数据库里的值加一     * @param key 业务主键     * @return 当前值     */    public String getNextValue(String key){        String currentValue = this.readCurrentValueFromDatabase(key);        String result;        if (currentValue =http://www.mamicode.com/= null || "".equals(currentValue)){            result = this.formatString(MIN_VALUE);            this.instrtIntoDataBase(key,(MIN_VALUE+1)+"");            BerkeleyDBUtil.getDatabase().getEnvironment().sync();        }        else{            int intCurrentValue =http://www.mamicode.com/ Integer.parseInt(currentValue);            result = this.formatString(intCurrentValue);            //存储下一个值            String nextValue = http://www.mamicode.com/"";            if (intCurrentValue =http://www.mamicode.com/= MAX_VALUE){                nextValue = MIN_VALUE+"";            }else {                nextValue = (intCurrentValue+1) +"";            }            this.instrtIntoDataBase(key,nextValue);            BerkeleyDBUtil.getDatabase().getEnvironment().sync();        }        return result;    }    public String readCurrentValueFromDatabase(String key){        DatabaseEntry theKey = new DatabaseEntry(StringUtils.toUTF8(key));        DatabaseEntry theValue = new DatabaseEntry();        TransactionConfig txnConfig = new TransactionConfig();        txnConfig.setSerializableIsolationVoid(true);        Database database = BerkeleyDBUtil.getDatabase();        //Transaction txn = database.getEnvironment().beginTransaction(null,txnConfig);        OperationStatus status = database.get(null,theKey,theValue,LockMode.DEFAULT);        //对应的键不存在        if (status == OperationStatus.KEYEMPTY){            return null;        }        else if (status == OperationStatus.SUCCESS){            byte[] data =http://www.mamicode.com/ theValue.getData();            String result;            try {                result = new String(data,"UTF-8");            } catch (UnsupportedEncodingException e) {                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.                result = "";            }            return result;        }        return null;    }    public void instrtIntoDataBase(String key,String value){        DatabaseEntry theKey = new DatabaseEntry(StringUtils.toUTF8(key));        DatabaseEntry theValue = new DatabaseEntry(StringUtils.toUTF8(value));        TransactionConfig txnConfig = new TransactionConfig();        txnConfig.setSerializableIsolationVoid(true);        Database database = BerkeleyDBUtil.getDatabase();        //Transaction txn = database.getEnvironment().beginTransaction(null,txnConfig);        OperationStatus status = database.put(null,theKey,theValue);        if (status == OperationStatus.SUCCESS){            logger.info("保存成功");        }//        else if (status == OperationStatus.KEYEXIST){//            logger.info("");//        }    }    public String formatString(int input){        String result = "";        if(input > 1000){          result = input +"";        }else{            int length = (input+"").length();            if (length == 1){                result = "000"+input;            }            else if (length == 2){                result = "00"+input;            }else {                result = "0"+input;            }        }        return result;    }    public static void main(String[] args) {        SerialNumberGenerator generator = new SerialNumberGenerator();        String result = generator.getNextValue("jiao");        System.out.println("======"+result+"======");    }}