仅执行一次便显示重复的条目。查看数据库后，数据库中记录已插入、
com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Duplicate entry '20120323' for key 'PRIMARY'
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:931)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2870)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3118)
at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1313)
at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1232)
at xls.POITest.readExcelToMysql(POITest.java:110)
at xls.POITest.main(POITest.java:121)
数据导入失败