hi,i want to start database which can accept tcp/ip connecttions,now there is a question: i start database with the command: /usr/local/pgsql/bin/postmaster -o "-i" -D /usr/local/pgsql/data and edit pg_hba.conf with adding the line : host all all 127.0.0.1/32 trust host rftDatabase globus 127.0.0.1 255.255.255.255 trust and after that i cant use psql to connect the database,here is the message: psql: FATAL: invalid command-line arguments for server process HINT: Try "postgres --help" for more information. but if i start with : /usr/local/pgsql/bin/postmaster -o -i -D /usr/local/pgsql/data then i can connet database psql command, in two situation i cat connect database with the file: String url="jdbc:postgresql://xiaohua/rftDatabase"; String user = "globus"; String password = "globus"; try { Class.forName("org.postgresql.Driver"); System.out.println("9999999999"); } catch(Exception ex) { System.out.println("Sub ------------: " + ex); } the error message is that: Unable to connect====================== org.postgresql.util.PSQLException: 连接尝试失败。 at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:136) at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:65) at org.postgresql.jdbc2.AbstractJdbc2Connection.(AbstractJdbc2Connection.java:117) at org.postgresql.jdbc3.AbstractJdbc3Connection.(AbstractJdbc3Connection.java:30) at org.postgresql.jdbc3.Jdbc3Connection.(Jdbc3Connection.java:24) at org.postgresql.Driver.connect(Driver.java:235) at java.sql.DriverManager.getConnection(DriverManager.java:512) at java.sql.DriverManager.getConnection(DriverManager.java:171) at TableDisplay.(TableDisplay.java:39) at TableDisplay.main(TableDisplay.java:158) Caused by: java.net.SocketException: Invalid argument or cannot assign requested address at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:305) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:171) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:158) at java.net.Socket.connect(Socket.java:452) at java.net.Socket.connect(Socket.java:402) at java.net.Socket.(Socket.java:309) at java.net.Socket.(Socket.java:124) at org.postgresql.core.PGStream.(PGStream.java:58) at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:77) ... 9 more Exception in thread "main" java.lang.NullPointerException at TableDisplay.getTable(TableDisplay.java:69) at TableDisplay.(TableDisplay.java:55) at TableDisplay.main(TableDisplay.java:158) the jdbc driver is rightly confirmed and the classpath is right. this question exists for few days and how should do next?thaks for your attention!