启动本地Play服务器时无法连接PostgreSQL默认数据库求助

Hey there, let's troubleshoot this "could not connect to database [default]" error step by step. First, could you share the specific details from your setup? I'll need:

• The relevant database dependency section from your build.sbt (like Play JDBC/Play Slick and PostgreSQL driver lines)
• The full db.default configuration block from your application.conf
• The exact output of Postgres' \conninfo command

In the meantime, here are some common checks you can run on your own to rule out obvious issues:

Dependency & Configuration Checks #

• Verify your build dependencies: Make sure you've included the correct PostgreSQL driver in your build.sbt (e.g., "org.postgresql" % "postgresql" % "42.7.1" for recent versions) along with Play's database connector (either play-jdbc for basic JDBC access or play-slick if you're using Slick ORM). Missing or outdated dependencies are a frequent culprit here.
• Cross-check connection parameters: Compare every value in your db.default config against what \conninfo shows:
  • db.default.url: Ensure the JDBC URL follows the format jdbc:postgresql://host:port/dbname and that host, port, and database name match exactly what's in \conninfo. For local connections, host is usually localhost or 127.0.0.1, port defaults to 5432.
  • db.default.user & db.default.password: Confirm these credentials match the role you're using to connect via Postgres CLI. Typos here are super easy to miss!

Server & Access Checks #

• Confirm Postgres is running: Try connecting directly with the psql command using the same credentials from your config (e.g., psql -U your_user -d your_db -h localhost). If this fails, your Postgres server might not be started.
• Validate user permissions: Ensure the database role you're using has been granted access to the target database. You can run this command in Postgres CLI if needed:

  GRANT ALL PRIVILEGES ON DATABASE your_db_name TO your_user;
  

• Check pg_hba.conf settings: This file controls which clients can connect to Postgres. Make sure there's a rule allowing local connections—for example:

  host    all             all             127.0.0.1/32            md5
  local   all             all                                     md5
  

  After modifying this file, reload Postgres with sudo systemctl reload postgresql (on Linux) or the equivalent for your OS.

Once you share your specific config snippets and \conninfo output, we can pinpoint the exact issue more quickly!

内容的提问来源于stack exchange，提问作者Ran