DAO
增删改查，其实就用到了改和查
public interface MysqlSequenceDAO {
/**
*
*/
public int createSequence(MysqlSequenceBo bo);
public int updSequence(@Param("seqName") String seqName, @Param("oldValue") long oldValue ,@Param("newValue") long newValue);
public int delSequence(@Param("seqName") String seqName);
public MysqlSequenceBo getSequence(@Param("seqName") String seqName);
public List<MysqlSequenceBo> getAll();
}Mapper
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.xxxxx.core.sequence.impl.dao.MysqlSequenceDAO" >
<resultMap id="BaseResultMap" type="com.xxxxx.core.sequence.impl.MysqlSequenceBo" >
<result column="SEQ_NAME" property="seqName" jdbcType="VARCHAR" />
<result column="SEQ_VALUE" property="seqValue" jdbcType="BIGINT" />
<result column="MIN_VALUE" property="minValue" jdbcType="BIGINT" />
<result column="MAX_VALUE" property="maxValue" jdbcType="BIGINT" />
<result column="STEP" property="step" jdbcType="BIGINT" />
<result column="TM_CREATE" property="tmCreate" jdbcType="TIMESTAMP" />
<result column="TM_SMP" property="tmSmp" jdbcType="TIMESTAMP" />
</resultMap>
<delete id="delSequence" parameterType="java.lang.String" >
delete from t_pub_sequence
where SEQ_NAME = #{seqName,jdbcType=VARCHAR}
</delete>
<insert id="createSequence" parameterType="com.xxxxx.core.sequence.impl.MysqlSequenceBo" >
insert into t_pub_sequence (SEQ_NAME,SEQ_VALUE,MIN_VALUE,MAX_VALUE,STEP,TM_CREATE)
values (#{seqName,jdbcType=VARCHAR}, #{seqValue,jdbcType=BIGINT},
#{minValue,jdbcType=BIGINT}, #{maxValue,jdbcType=BIGINT}, #{step,jdbcType=BIGINT},
now())
</insert>
<update id="updSequence" parameterType="com.xxxxx.core.sequence.impl.MysqlSequenceBo" >
update t_pub_sequence
set SEQ_VALUE = #{newValue,jdbcType=BIGINT}
where SEQ_NAME = #{seqName,jdbcType=VARCHAR} and SEQ_VALUE = #{oldValue,jdbcType=BIGINT}
</update>
<select id="getAll" resultMap="BaseResultMap" >
select SEQ_NAME, SEQ_VALUE, MIN_VALUE, MAX_VALUE, STEP
from t_pub_sequence
</select>
<select id="getSequence" resultMap="BaseResultMap" >
select SEQ_NAME, SEQ_VALUE, MIN_VALUE, MAX_VALUE, STEP
from t_pub_sequence
where SEQ_NAME = #{seqName,jdbcType=VARCHAR}
</select>
</mapper>接口实现
@Repository("mysqlSequence")
public class MysqlSequenceImpl implements MysqlSequence{
@Autowired
private MysqlSequenceFactory mysqlSequenceFactory;
/**
* <p>
* 获取指定sequence的序列号
* </p>
*
* @param seqName sequence名
* @return String 序列号
* @author coderzl
*/
@Override
public String nextVal(String seqName) {
return Objects.toString(mysqlSequenceFactory.getNextVal(seqName));
}
}工厂
工厂只做了两件事
?服务启动的时候，初始化数据库中所有sequence【完成序列区间缓存】
?获取sequence的下一个值
@Component
public class MysqlSequenceFactory {
private final Lock lock = new ReentrantLock();
/** */
private Map<String,MysqlSequenceHolder> holderMap = new ConcurrentHashMap<>();
@Autowired
private MysqlSequenceDAO msqlSequenceDAO;
/** 单个sequence初始化乐观锁更新失败重试次数 */
@Value("${seq.init.retry:5}")
private int initRetryNum;
/** 单个sequence更新序列区间乐观锁更新失败重试次数 */
@Value("${seq.get.retry:20}")
private int getRetryNum;
@PostConstruct
private void init(){
//初始化所有sequence
initAll();
}
/**
* <p> 加载表中所有sequence，完成初始化 </p>
* @return void
* @author coderzl
*/
private void initAll(){
try {
lock.lock();
List<MysqlSequenceBo> boList = msqlSequenceDAO.getAll();
if (boList == null) {
throw new IllegalArgumentException("The sequenceRecord is null!");
}
for (MysqlSequenceBo bo : boList) {
MysqlSequenceHolder holder = new MysqlSequenceHolder(msqlSequenceDAO, bo,initRetryNum,getRetryNum);
holder.init();
holderMap.put(bo.getSeqName(), holder);
}
}finally {
lock.unlock();
}
}
/**
* <p> </p>
* @param seqName
* @return long
* @author coderzl
*/
public long getNextVal(String seqName){
MysqlSequenceHolder holder = holderMap.get(seqName);
if (holder == null) {
try {
lock.lock();
holder = holderMap.get(seqName);
if (holder != null){
return holder.getNextVal();
}
MysqlSequenceBo bo = msqlSequenceDAO.getSequence(seqName);
holder = new MysqlSequenceHolder(msqlSequenceDAO, bo,initRetryNum,getRetryNum);
holder.init();
holderMap.put(seqName, holder);
}finally {
lock.unlock();
}
}
return holder.getNextVal();
}
}单一sequence的Holder
?init() 初始化 其中包括参数校验，数据库记录更新，创建序列区间
?getNextVal() 获取下一个值
public class MysqlSequenceHolder {
private final Lock lock = new ReentrantLock();
/** seqName */
private String seqName;
/** sequenceDao */
private MysqlSequenceDAO sequenceDAO;
private MysqlSequenceBo sequenceBo;
/** */
private SequenceRange sequenceRange;
/** 是否初始化 */
private volatile boolean isInitialize = false;
/** sequence初始化重试次数 */
private int initRetryNum;
/** sequence获取重试次数 */
private int getRetryNum;
/**
* <p> 构造方法 </p>
* @Title MysqlSequenceHolder
* @param sequenceDAO
* @param sequenceBo
* @param initRetryNum 初始化时，数据库更新失败后重试次数
* @param getRetryNum 获取nextVal时，数据库更新失败后重试次数
* @return
* @author coderzl
*/
public MysqlSequenceHolder(MysqlSequenceDAO sequenceDAO, MysqlSequenceBo sequenceBo,int initRetryNum,int getRetryNum) {
this.sequenceDAO = sequenceDAO;
this.sequenceBo = sequenceBo;
this.initRetryNum = initRetryNum;
this.getRetryNum = getRetryNum;
if(sequenceBo != null)
this.seqName = sequenceBo.getSeqName();
}
/**
* <p> 初始化 </p>
* @Title init
* @param
* @return void
* @author coderzl
*/
public void init(){
if (isInitialize == true) {
throw new SequenceException("[" + seqName + "] the MysqlSequenceHolder has inited");
}
if (sequenceDAO == null) {
throw new SequenceException("[" + seqName + "] the sequenceDao is null");
}
if (seqName == null (北联网教程,专业提供视频软件下载)
……