Question

java 连接 mysql时Communications link failure

public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");

conn = DriverManager
.getConnection("jdbc:mysql://localhost/mydata?user=root&password=root");
stmt = conn.createStatement();
rs = stmt.executeQuery("select * from dept");
while (rs.next()) {
System.out.println(rs.getString("deptno"));
}

} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException ex) {
// handle any errors
System.out.println("SQLException: " + ex.getMessage());
System.out.println("SQLState: " + ex.getSQLState());
System.out.println("VendorError: " + ex.getErrorCode());
} finally {
try {
if(rs != null) {
rs.close();
rs = null;
}
if(stmt != null) {
stmt.close();
stmt = null;
}
if(conn != null) {
conn.close();
conn = null;
}
} catch (SQLException e) {
e.printStackTrace();
}
}

}

}

Answer 1

把localhost换成127.0.0.1看看，看看防火墙的3306端口打开没有，检查mysql看看用的是不是不是3306。

Answer 2

localhost:3306
再检查一下你的网络连接