Io 異常: The Network Adapter could not establish the connection

異常如下：

org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Io 異常: The Network Adapter could not establish the connection)
  at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1225)
  at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
 Caused by: java.sql.SQLException: Io 異常: The Network Adapter could not establish the connection
  at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:180)
  at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:222)
  at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:335)
 

主要原因：

1.可能是server.xml檔案的DataSource配置出錯。

(1).如果用到的是本機上的資料，本機資料源裡的部分配置為： username="pcisv62" password="11" url="jdbc:oracle:thin:@localhost:1521:orcl"
(2).如果用到的是伺服器上的資料，則資料來源裡的部分配置為： username="pcisv62" password="11" url="jdbc:oracle:thin:@dbserver:1521:corev6"

（dbserver為伺服器的名字，corev6為伺服器上Oracle的SID）

2.可能是oracle的tnsnames.ora檔案配置出錯。

oracle的安裝目錄E:\oracle\ora92\network\admin下的tnsnames.ora：
本地配置：
ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 主機名稱)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = ORCL)
    )
  )
或伺服器配置：
COREV6_DBSERVER =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SID = COREV6)
      (SERVER = DEDICATED)
    )
  )