如何解决错误：java.sql.SQLNonTransientConnectionException：无法创建与数据库服务器的连接

Posted 2023-01-06

这是我的代码

private String dbURL;
private String dbUsername = "root";
private String dbPassword = "root1234";
private String URL = "localhost";
private String port = "3306";
private String dbName = "university";
private Connection con;

private void connectToDataBase() throws ClassNotFoundException, SQLException 

    dbURL = "jdbc:mysql://" + URL + ":" + port + "/" + dbName + "?verifyServerCertificate=false";
    Properties p = new Properties();
    p.setProperty("user", dbUsername);
    p.setProperty("password", dbPassword);
    p.setProperty("useSSL", "false");
    p.setProperty("autoReconnect", "true");
    Class.forName("com.mysql.cj.jdbc.Driver");

    con = DriverManager.getConnection(dbURL, p);

我遇到了这个问题java.sql.SQLNonTransientConnectionException：无法创建与数据库服务器的连接。尝试重新连接3次。放弃。enter image description here

答案

您正在添加URL的额外内容；首先，您声明了这一点：

private String URL = "jdbc:mysql://localhost:3306";

现在，在connectToDatabase方法中，您通过在以下网址之间放置该URL来构建dbURL：

dbURL = "jdbc:mysql://" + URL + ":" + port + "/" + dbName + "?verifyServerCertificate=false";

您的实际dbURL实际上将如下所示：dbURL =“ jdbc：mysql：//” +“ jdbc：mysql：// localhost：3306” +“：” +端口+“ /” + dbName +“？verifyServerCertificate = false”;

因此，将URL初始化为：

 URL = "localhost";

另一答案

我只是想通过提供的详细信息来帮助解决问题：）。尝试，

dbURL = "jdbc:mysql://" + URL + ":" + port + "/" + dbName + "?verifyServerCertificate=false"+ "&useSSL=false";

Properties p = new Properties();
p.setProperty("user", dbUsername);
p.setProperty("password", dbPassword);

Class.forName("com.mysql.cj.jdbc.Driver");

con = DriverManager.getConnection(dbURL, p);

注意：我没有设置"autoReconnect", "true"