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@@ -0,0 +1,424 @@
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+package com.fs.utils;
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+
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+import java.math.BigInteger;
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+import java.security.MessageDigest;
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+import java.security.NoSuchAlgorithmException;
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+import java.security.SecureRandom;
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+import java.util.concurrent.ThreadLocalRandom;
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+import java.util.concurrent.atomic.AtomicLong;
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+import java.util.concurrent.locks.ReentrantReadWriteLock;
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+
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+/**
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+ * 短码生成工具类 - 高并发、高唯一性短码生成器
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+ * 修复版本：解决数组越界和线程获取问题
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+ *
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+ * @author ToolKit
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+ * @version 1.0.2
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+ */
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+public final class ShortCodeGeneratorUtils {
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+
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+ // 私有构造器，防止实例化
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+ private ShortCodeGeneratorUtils() {
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+ throw new AssertionError("Cannot instantiate utility class");
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+ }
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+
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+ /**
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+ * 字符集定义枚举
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+ */
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+ public enum CharsetType {
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+
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+ /** URL安全字符集（推荐） */
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+ URL_SAFE("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
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+
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+ private final String chars;
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+
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+ CharsetType(String chars) {
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+ this.chars = chars;
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+ }
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+
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+ public String getChars() {
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+ return chars;
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+ }
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+
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+ public char[] getCharArray() {
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+ return chars.toCharArray();
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+ }
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+
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+ public int size() {
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+ return chars.length();
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+ }
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+ }
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+
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+ // 默认配置
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+ private static final CharsetType DEFAULT_CHARSET = CharsetType.URL_SAFE;
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+
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+ // 单例实例（延迟加载）
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+ private static class InstanceHolder {
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+ static final ShortCodeGenerator INSTANCE = new ShortCodeGenerator(DEFAULT_CHARSET);
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+ }
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+
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+ /**
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+ * 获取默认生成器实例
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+ */
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+ public static ShortCodeGenerator getInstance() {
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+ return InstanceHolder.INSTANCE;
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+ }
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+
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+ /**
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+ * 获取指定字符集的生成器实例
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+ */
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+ public static ShortCodeGenerator getInstance(CharsetType charsetType) {
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+ return new ShortCodeGenerator(charsetType);
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+ }
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+
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+ /**
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+ * 快速生成8位短码（使用默认配置）
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+ */
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+ public static String generate8() {
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+ return getInstance().generate8CharCode();
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+ }
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+
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+ /**
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+ * 快速生成6位短码（使用默认配置）
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+ */
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+ public static String generate6() {
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+ return getInstance().generate6CharCode();
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+ }
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+
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+ /**
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+ * 快速生成指定长度短码（使用默认配置）
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+ */
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+ public static String generate(int length) {
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+ return getInstance().generateCode(length);
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+ }
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+
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+ /**
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+ * 短码生成器核心实现 - 完全修复版本
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+ */
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+ public static class ShortCodeGenerator {
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+
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+ private final char[] charset;
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+ private final int charsetSize;
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+ private final AtomicLong counter = new AtomicLong(0);
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+ private volatile long lastTimestamp = 0;
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+ private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
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+ private final SecureRandom secureRandom;
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+ private static final long PROCESS_ID = getProcessId();
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+
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+ /**
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+ * 使用默认字符集创建生成器
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+ */
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+ public ShortCodeGenerator() {
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+ this(DEFAULT_CHARSET);
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+ }
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+
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+ /**
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+ * 使用指定字符集创建生成器
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+ */
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+ public ShortCodeGenerator(CharsetType charsetType) {
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+ this.charset = charsetType.getCharArray();
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+ this.charsetSize = charsetType.size();
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+ this.secureRandom = new SecureRandom();
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+ // 初始化安全随机数生成器
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+ secureRandom.nextBytes(new byte[16]);
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+ }
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+
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+ /**
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+ * 生成8位短码
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+ */
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+ public String generate8CharCode() {
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+ return generateCode(8);
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+ }
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+
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+ /**
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+ * 生成6位短码
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+ */
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+ public String generate6CharCode() {
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+ return generateCode(6);
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+ }
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+
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+ /**
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+ * 生成指定长度短码
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+ */
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+ public String generateCode(int length) {
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+ validateLength(length);
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+
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+ try {
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+ // 组合多种生成策略降低碰撞概率
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+ String codeByTime = generateByTimestamp(length);
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+ String codeByHash = generateByHash(length);
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+
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+ return mixAndFinalize(codeByTime, codeByHash, length);
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+ } catch (Exception e) {
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+ // 如果任何方法失败，使用安全的降级方案
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+ return generateSafeFallbackCode(length);
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+ }
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+ }
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+
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+ /**
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+ * 批量生成短码
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+ */
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+ public String[] generateBatch(int count, int length) {
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+ validateLength(length);
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+
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+ String[] codes = new String[count];
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+
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+ for (int i = 0; i < count; i++) {
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+ codes[i] = generateCode(length);
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+ }
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+
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+ return codes;
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+ }
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+
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+ /**
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+ * 获取字符集大小
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+ */
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+ public int getCharsetSize() {
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+ return charsetSize;
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+ }
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+
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+ /**
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+ * 获取字符集
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+ */
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+ public String getCharsetString() {
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+ return new String(charset);
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+ }
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+
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+ /**
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+ * 验证长度参数
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+ */
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+ private void validateLength(int length) {
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+ if (length < 4 || length > 16) {
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+ throw new IllegalArgumentException("Length must be between 4 and 16");
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+ }
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+ }
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+
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+ /**
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+ * 安全的降级生成方案
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+ */
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+ private String generateSafeFallbackCode(int length) {
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+ char[] result = new char[length];
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+ ThreadLocalRandom random = ThreadLocalRandom.current();
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+
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+ for (int i = 0; i < length; i++) {
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+ // 使用安全的随机数生成，确保索引为正数
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+ int index = random.nextInt(charsetSize);
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+ result[i] = charset[index];
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+ }
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+
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+ return new String(result);
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+ }
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+
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+ /**
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+ * 基于时间戳生成 - 修复线程ID获取问题
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+ */
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+ private String generateByTimestamp(int length) {
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+ long currentTime = System.currentTimeMillis();
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+ long sequence;
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+
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+ lock.writeLock().lock();
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+ try {
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+ if (currentTime == lastTimestamp) {
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+ sequence = counter.incrementAndGet();
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+ } else {
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+ lastTimestamp = currentTime;
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+ counter.set(0);
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+ sequence = 0;
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+ }
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+ } finally {
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+ lock.writeLock().unlock();
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+ }
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+
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+ ThreadLocalRandom random = ThreadLocalRandom.current();
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+ long randomPart = random.nextLong();
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+
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+ // 获取当前线程ID
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+ long threadId = Thread.currentThread().getId();
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+
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+ // 组合各种熵源
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+ long combined = currentTime ^ (sequence << 16) ^ randomPart;
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+ combined ^= System.nanoTime();
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+ combined ^= (PROCESS_ID << 48);
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+ combined ^= (threadId << 32);
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+
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+ // 确保为正数
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+ combined = Math.abs(combined);
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+ if (combined == Long.MIN_VALUE) {
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+ combined = Long.MAX_VALUE; // 处理边界情况
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+ }
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+
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+ return convertToBaseSafe(combined, length);
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+ }
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+
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+ /**
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+ * 基于哈希算法生成 - 修复线程ID获取问题
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+ */
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+ private String generateByHash(int length) {
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+ try {
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+ MessageDigest md = MessageDigest.getInstance("SHA-256");
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+
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+ // 使用多个熵源确保唯一性
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+ StringBuilder entropy = new StringBuilder();
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+ entropy.append(System.nanoTime())
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+ .append(Thread.currentThread().getId()) // 修复这里
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+ .append(System.identityHashCode(this))
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+ .append(secureRandom.nextLong())
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+ .append(counter.get())
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+ .append(Runtime.getRuntime().freeMemory());
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+
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+ byte[] hash = md.digest(entropy.toString().getBytes());
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+
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+ // 使用BigInteger避免负数和溢出问题
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+ BigInteger bigInt = new BigInteger(1, hash); // 正数模式
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+ BigInteger modValue = BigInteger.valueOf(charsetSize).pow(length);
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+
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+ // 取模确保值在范围内
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+ BigInteger result = bigInt.mod(modValue);
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+
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+ return convertBigIntegerToBase(result, length);
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+
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+ } catch (NoSuchAlgorithmException e) {
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+ // 降级方案：使用增强随机数
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+ return generateEnhancedRandomCode(length);
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+ }
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+ }
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+
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+ /**
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+ * 增强随机数生成
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+ */
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+ private String generateEnhancedRandomCode(int length) {
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+ char[] result = new char[length];
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+
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+ for (int i = 0; i < length; i++) {
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+ // 使用安全的随机索引生成
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+ int index = secureRandom.nextInt(charsetSize);
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+ result[i] = charset[index];
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+ }
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+
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+ return new String(result);
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+ }
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+
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+ /**
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+ * 安全的进制转换 - 完全修复版本
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+ */
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+ private String convertToBaseSafe(long number, int length) {
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+ char[] result = new char[length];
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+
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+ // 确保number为正数
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+ long temp = Math.abs(number);
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+ if (temp == 0) {
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+ temp = System.nanoTime() & 0x7FFFFFFF; // 使用纳秒时间作为备用值
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+ }
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+
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+ // 基本转换
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+ for (int i = length - 1; i >= 0; i--) {
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+ long remainder = temp % charsetSize;
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+ int index = (int) remainder;
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+
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+ // 确保索引在有效范围内
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+ if (index < 0) {
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+ index = (int) Math.abs(remainder);
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+ }
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+ index = index % charsetSize;
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+
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+ result[i] = charset[index];
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+ temp = temp / charsetSize;
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+ }
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+
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+ return new String(result);
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+ }
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+
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+ /**
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+ * BigInteger版本的安全进制转换
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+ */
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+ private String convertBigIntegerToBase(BigInteger number, int length) {
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+ char[] result = new char[length];
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+ BigInteger base = BigInteger.valueOf(charsetSize);
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+ BigInteger temp = number;
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+
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+ // 确保temp为正数
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+ if (temp.signum() < 0) {
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+ temp = temp.abs();
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+ }
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+
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+ for (int i = length - 1; i >= 0; i--) {
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+ BigInteger[] divResult = temp.divideAndRemainder(base);
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+ int index = divResult[1].intValue();
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+
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+ // 确保索引为正数且在范围内
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+ if (index < 0) {
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+ index = -index;
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+ }
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+ index = index % charsetSize;
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+
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+ result[i] = charset[index];
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+ temp = divResult[0];
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+ }
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+
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+ return new String(result);
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+ }
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+
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+ /**
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+ * 混合并最终化代码
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+ */
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+ private String mixAndFinalize(String code1, String code2, int length) {
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+ char[] result = new char[length];
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+
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+ for (int i = 0; i < length; i++) {
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+ char c1 = code1.charAt(i % code1.length());
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+ char c2 = code2.charAt((i + 1) % code2.length());
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+
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+ // 使用安全的混合方法
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+ int mixed = safeMixChars(c1, c2, i);
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+ result[i] = charset[mixed];
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+ }
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+
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+ return new String(result);
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+ }
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+
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+ /**
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+ * 安全的字符混合
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+ */
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+ private int safeMixChars(char c1, char c2, int position) {
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+ long l1 = (long) c1;
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+ long l2 = (long) c2;
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+
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+ // 使用不同的混合策略，但都确保结果为非负数
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+ long mixedLong;
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+ switch (position % 4) {
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+ case 0:
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+ mixedLong = (l1 + l2 * 31L) % charsetSize;
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+ break;
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+ case 1:
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+ mixedLong = (l1 ^ l2) % charsetSize;
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+ break;
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+ case 2:
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+ mixedLong = (l1 * 17L + l2) % charsetSize;
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+ break;
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+ default:
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+ mixedLong = (l1 * 3L + l2 * 7L) % charsetSize;
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+ break;
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+ }
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+
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+ // 确保结果为正数
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+ int mixed = (int) Math.abs(mixedLong) % charsetSize;
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+ return mixed;
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+ }
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+
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+ /**
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+ * 获取进程ID
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+ */
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+ private static long getProcessId() {
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+ try {
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+ String processName = java.lang.management.ManagementFactory
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+ .getRuntimeMXBean()
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+ .getName();
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+ String pidStr = processName.split("@")[0];
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+ return Long.parseLong(pidStr) & 0xFFFF; // 限制范围
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+ } catch (Exception e) {
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+ // 返回备用值
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+ return Thread.currentThread().getId() & 0xFFFF;
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+ }
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+ }
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+ }
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+}
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