java network_error ai_generated true

java.sql.SQLNonTransientConnectionException：无法连接到地址=(host=<host>)(port=<port>)(type=master)：连接被拒绝

java.sql.SQLNonTransientConnectionException: Could not connect to address=(host=<host>)(port=<port>)(type=master): Connection refused

ID: java/sql-non-transient-connection-exception

其他格式: JSON · Markdown 中文 · English
85%修复率
85%置信度
1证据数
2023-08-15首次发现

版本兼容性

版本状态引入弃用备注
MySQL Connector/J 8.0.33 active — — —
PostgreSQL JDBC 42.7.1 active — — —
HikariCP 5.1.0 active — — —

根因分析

JDBC驱动程序无法建立到指定数据库主机和端口的TCP连接，通常是因为数据库服务器未运行、端口被防火墙阻止或主机名不可达。

English

The JDBC driver cannot establish a TCP connection to the specified database host and port, typically because the database server is not running, the port is blocked by a firewall, or the hostname is unreachable.

generic

官方文档

https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-usagenotes-connect-driver-manager.html

解决方案

  1. Verify the database server is running and listening on the expected port. On Linux: `sudo netstat -tulpn | grep <port>`. On Windows: `netstat -ano | findstr :<port>`. If not listening, restart the database service.
  2. Check firewall rules on both host and network level. Temporarily disable the firewall for testing: `sudo ufw disable` (Linux) or `netsh advfirewall set allprofiles state off` (Windows). Re-enable after testing and add an allow rule for the database port.
  3. Test connectivity using telnet or nc from the application server: `telnet <host> <port>` or `nc -zv <host> <port>`. If the connection fails, check DNS resolution with `nslookup <host>` and ensure the hostname resolves to the correct IP.

无效尝试

常见但无效的做法:

  1. Increase connection timeout in JDBC URL (e.g., connectTimeout=60000) 95% 失败

    Timeout only affects how long the driver waits for a response; if the server is down or port is closed, timeout does not help. The connection will still fail after the extended timeout.

  2. Change the JDBC driver version to an older one 90% 失败

    The error is a network-level issue, not a driver compatibility problem. Changing the driver version does not affect TCP connectivity to the database server.

  3. Add useSSL=false to the JDBC URL 85% 失败

    SSL configuration is irrelevant when the initial TCP connection cannot be established. The connection refusal happens before any SSL handshake.