Java分布式ID

在Java中生成分布式唯一ID的常见方法是使用UUID或者结合数据库生成唯一ID。以下是一个使用数据库生成唯一ID的例子：

1. 在数据库中创建一个序列（如果数据库支持的话）。
2. 在插入新记录时，使用该序列生成唯一ID。

以下是一个简单的例子，使用MySQL数据库和JDBC来生成分布式唯一ID：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.UUID;
 
public class DistributedIdGenerator {
 
    private static final String DB_URL = "jdbc:mysql://localhost:3306/yourdatabase";
    private static final String USER = "yourusername";
    private static final String PASS = "yourpassword";
    private static final String INSERT_SQL = "INSERT INTO your_table (id, data) VALUES (?, ?)";
    private static final String GET_NEXT_ID_SQL = "SELECT LAST_INSERT_ID()";
 
    public static String generateId() {
        return UUID.randomUUID().toString();
    }
 
    public static long getNextId(String connectionId) throws SQLException {
        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS)) {
            PreparedStatement statement = connection.prepareStatement(GET_NEXT_ID_SQL);
            try (ResultSet resultSet = statement.executeQuery()) {
                resultSet.next();
                return resultSet.getLong(1);
            }
        }
    }
 
    public static void insertData(String id, String data) throws SQLException {
        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS)) {
            PreparedStatement statement = connection.prepareStatement(INSERT_SQL);
            statement.setString(1, id);
            statement.setString(2, data);
            statement.executeUpdate();
        }
    }
 
    public static void main(String[] args) {
        try {
            String id = generateId();
            insertData(id, "Some data");
            long nextId = getNextId(id);
            System.out.println("Generated ID: