refactor(jpa): 将 Snowflake ID 生成逻辑抽取为公共工具类

spring-boot-service-template-common/src/main/java/com/lanyuanxiaoyao/service/template/common/helper/SnowflakeHelper.java

@@ -0,0 +1,68 @@
+package com.lanyuanxiaoyao.service.template.common.helper;
+
+import java.time.Instant;
+
+public class SnowflakeHelper {
+  /**
+   * 起始的时间戳
+   */
+  private final static long START_TIMESTAMP = 1;
+
+  /**
+   * 序列号占用的位数
+   */
+  private final static long SEQUENCE_BIT = 11;
+
+  /**
+   * 序列号最大值
+   */
+  private final static long MAX_SEQUENCE_BIT = ~(-1 << SEQUENCE_BIT);
+
+  /**
+   * 时间戳值向左位移
+   */
+  private final static long TIMESTAMP_OFFSET = SEQUENCE_BIT;
+
+  /**
+   * 序列号
+   */
+  private static long sequence = 0;
+  /**
+   * 上一次时间戳
+   */
+  private static long lastTimestamp = -1;
+
+  public static synchronized long next() {
+    long currentTimestamp = nowTimestamp();
+    if (currentTimestamp < lastTimestamp) {
+      throw new RuntimeException("Clock have moved backwards.");
+    }
+
+    if (currentTimestamp == lastTimestamp) {
+      // 相同毫秒内, 序列号自增
+      sequence = (sequence + 1) & MAX_SEQUENCE_BIT;
+      // 同一毫秒的序列数已经达到最大
+      if (sequence == 0) {
+        currentTimestamp = nextTimestamp();
+      }
+    } else {
+      // 不同毫秒内, 序列号置为0
+      sequence = 0;
+    }
+
+    lastTimestamp = currentTimestamp;
+    return (currentTimestamp - START_TIMESTAMP) << TIMESTAMP_OFFSET | sequence;
+  }
+
+  private static long nextTimestamp() {
+    long milli = nowTimestamp();
+    while (milli <= lastTimestamp) {
+      milli = nowTimestamp();
+    }
+    return milli;
+  }
+
+  private static long nowTimestamp() {
+    return Instant.now().toEpochMilli();
+  }
+}

spring-boot-service-template-jpa/src/main/java/com/lanyuanxiaoyao/service/template/jpa/entity/SnowflakeIdGenerator.java

@@ -1,7 +1,7 @@
 package com.lanyuanxiaoyao.service.template.jpa.entity;
 
+import com.lanyuanxiaoyao.service.template.common.helper.SnowflakeHelper;
 import java.io.Serializable;
-import java.time.Instant;
 import lombok.extern.slf4j.Slf4j;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.id.IdentifierGenerator;
@@ -11,75 +11,10 @@ public class SnowflakeIdGenerator implements IdentifierGenerator {
   @Override
   public Serializable generate(SharedSessionContractImplementor session, Object object) {
     try {
-      return Snowflake.next();
+      return SnowflakeHelper.next();
     } catch (Exception e) {
       log.error("Generate snowflake id failed", e);
       throw new RuntimeException(e);
     }
   }
-
-  public static class Snowflake {
-    /**
-     * 起始的时间戳
-     */
-    private final static long START_TIMESTAMP = 1;
-
-    /**
-     * 序列号占用的位数
-     */
-    private final static long SEQUENCE_BIT = 11;
-
-    /**
-     * 序列号最大值
-     */
-    private final static long MAX_SEQUENCE_BIT = ~(-1 << SEQUENCE_BIT);
-
-    /**
-     * 时间戳值向左位移
-     */
-    private final static long TIMESTAMP_OFFSET = SEQUENCE_BIT;
-
-    /**
-     * 序列号
-     */
-    private static long sequence = 0;
-    /**
-     * 上一次时间戳
-     */
-    private static long lastTimestamp = -1;
-
-    public static synchronized long next() {
-      long currentTimestamp = nowTimestamp();
-      if (currentTimestamp < lastTimestamp) {
-        throw new RuntimeException("Clock have moved backwards.");
-      }
-
-      if (currentTimestamp == lastTimestamp) {
-        // 相同毫秒内, 序列号自增
-        sequence = (sequence + 1) & MAX_SEQUENCE_BIT;
-        // 同一毫秒的序列数已经达到最大
-        if (sequence == 0) {
-          currentTimestamp = nextTimestamp();
-        }
-      } else {
-        // 不同毫秒内, 序列号置为0
-        sequence = 0;
-      }
-
-      lastTimestamp = currentTimestamp;
-      return (currentTimestamp - START_TIMESTAMP) << TIMESTAMP_OFFSET | sequence;
-    }
-
-    private static long nextTimestamp() {
-      long milli = nowTimestamp();
-      while (milli <= lastTimestamp) {
-        milli = nowTimestamp();
-      }
-      return milli;
-    }
-
-    private static long nowTimestamp() {
-      return Instant.now().toEpochMilli();
-    }
-  }
 }