用java代码实现mysql多租户数据隔离

实现MySQL多租户数据隔离的一种方法是在数据库中为每个租户创建单独的schema（即数据库），并将其与单独的用户关联起来。下面是使用Java代码实现该方法的步骤：

1. 创建一个Java类来管理数据库连接和操作。这个类应该包含以下方法：

public class TenantDatabaseManager {
 
  private static final String DATABASE_HOST = "localhost";
  private static final String DATABASE_USERNAME = "root";
  private static final String DATABASE_PASSWORD = "password";
  private static final String DATABASE_DRIVER = "com.mysql.jdbc.Driver";
 
  private Connection connection;
 
  public TenantDatabaseManager(String tenantId) throws SQLException, ClassNotFoundException {
    String databaseName = "tenant_" + tenantId;
    Class.forName(DATABASE_DRIVER);
    this.connection = DriverManager.getConnection("jdbc:mysql://" + DATABASE_HOST + "/" + databaseName, DATABASE_USERNAME, DATABASE_PASSWORD);
  }
 
  public void executeQuery(String query) throws SQLException {
    Statement statement = connection.createStatement();
    statement.executeQuery(query);
    statement.close();
  }
 
  public void executeUpdate(String query) throws SQLException {
    Statement statement = connection.createStatement();
    statement.executeUpdate(query);
    statement.close();
  }
 
  public void closeConnection() throws SQLException {
    this.connection.close();
  }
 
}

2. 创建一个Java类来管理租户列表。这个类应该包含以下方法：

public class TenantManager {
 
  private Map<String, TenantDatabaseManager> tenantDatabaseManagerMap = new HashMap<>();
 
  public void addTenant(String tenantId) throws SQLException, ClassNotFoundException {
    if (!tenantDatabaseManagerMap.containsKey(tenantId)) {
      TenantDatabaseManager tenantDatabaseManager = new TenantDatabaseManager(tenantId);
      tenantDatabaseManagerMap.put(tenantId, tenantDatabaseManager);
    }
  }
 
  public TenantDatabaseManager getTenantDatabaseManager(String tenantId) {
    return tenantDatabaseManagerMap.get(tenantId);
  }
 
  public void closeAllConnections() throws SQLException {
    for (TenantDatabaseManager tenantDatabaseManager : tenantDatabaseManagerMap.values()) {
      tenantDatabaseManager.closeConnection();
    }
    tenantDatabaseManagerMap.clear();
  }
 
}

3. 在每次请求到达时，从请求中获取租户ID，并使用TenantManager获取对应的TenantDatabaseManager对象。然后使用该对象执行数据库操作。

public class RequestHandler {
 
  private static final String TENANT_HEADER = "Tenant-Id";
 
  private TenantManager tenantManager;
 
  public RequestHandler() {
    tenantManager = new TenantManager();
  }
 
  public void handleRequest(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException, SQLException, ClassNotFoundException {
    String tenantId = request.getHeader(TENANT_HEADER);
    if (tenantId == null) {
      response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
      response.getWriter().println("Tenant Id is required.");
      return;
    }
 
    TenantDatabaseManager tenantDatabaseManager = tenantManager.getTenantDatabaseManager(tenantId);
    if (tenantDatabaseManager == null) {
      tenantManager.addTenant(tenantId);
      tenantDatabaseManager = tenantManager.getTenantDatabaseManager(tenantId);
    }
 
    // execute database operations using tenantDatabaseManager
    ...
  }
 
  public void destroy() throws SQLException {
    tenantManager.closeAllConnections();
  }
 
}

以上就是使用Java代码实现MySQL多租户数据隔离的方法。