连接不上数据库，请求大神帮忙

java.sql.SQLException: 网络通信异常
at dm.jdbc.dbaccess.DBError.throwSQLException(DBError.java:56)
at dm.jdbc.driver.DmdbConnection_bs.openConnection(DmdbConnection_bs.java:865)
at dm.jdbc.driver.DmdbConnection_bs.commInit(DmdbConnection_bs.java:823)
at dm.jdbc.driver.DmdbConnection_bs.initialize(DmdbConnection_bs.java:529)
at dm.jdbc.driver.DmdbConnection_bs.<init>(DmdbConnection_bs.java:421)
at dm.jdbc.driver.DmDriver_bs.connect(DmDriver_bs.java:96)
at dm.jdbc.driver.DmDriver.connect(DmDriver.java:85)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:154)
at org.logicalcobwebs.proxool.DefaultConnectionBuilder.buildConnection(DefaultConnectionBuilder.java:39)
at org.logicalcobwebs.proxool.Prototyper.buildConnection(Prototyper.java:159)
at org.logicalcobwebs.proxool.Prototyper.sweep(Prototyper.java:102)
at org.logicalcobwebs.proxool.PrototyperThread.run(PrototyperThread.java:44)