为什么我在运行简单Java程序时收到SQL State:28000 FATAL:Ident authentication failed for user错误消息?

我有一个 Postgres 11数据库安装在 VirtualBox 虚拟机正在运行 Centos7

我有以下使用单个依赖项的简单Java代码 postgresql-42.2.5 :

public class JavaApplication5 {

    public static void main(String[] args) {

        try (Connection conn = DriverManager.getConnection(
                "jdbc:postgresql://127.0.0.1:5332/mydb", "mydbuser", "mydbpassword")) {

            if (conn != null) {
                System.out.println("Connected to the database!");
            } else {
                System.out.println("Failed to make connection!");
            }

        } catch (SQLException e) {
            System.err.format("SQL State: %s\n%s", e.getSQLState(), e.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
}

java -jar JavaApplication5.jar 

我得到的结果是:

Connected to the database!

所以很明显,这意味着我可以连接到Postgres数据库从我的主机到我的客人。接下来,我测试是否可以直接从我的客人那里连接。因此,我将“JavaApplication5.jar”复制到运行centos7的客户虚拟机中,并重新运行相同的命令。不过,这次我从同一个可执行jar文件中得到以下消息:

SQL State: 28000
FATAL: Ident authentication failed for user "mydbuser"

有人知道为什么我在来宾虚拟机上而不是主机上出现此错误吗?

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     trust
# IPv4 local connections:
host    all             all             127.0.0.1/32            ident
# IPv6 local connections:
host    all             all             ::1/128                 ident
# Allow replication connections from localhost, by a user with the
# replication privilege.
local   replication     all                                     peer
host    replication     all             127.0.0.1/32            ident
host    replication     all             ::1/128                 ident
host all all 0.0.0.0/0 md5