【发布时间】：2013-08-16 00:40:06
【问题描述】：
下面的类会将 .csv 导入数据库表。它工作正常，现在我需要更新同一个表中需要获取当前系统时间戳的另一列 当该程序在数据库表的相应列中执行时得到更新。
示例：在 Db2 表中，主题列是： 英语社会数学时间戳
在 .CSV 文件中只有 3 列 Eng Social Maths 。
当 .csv 文件被导入（使用上述程序）到 db2 时，所有列都会更新，除了 TimeStamp。 时间戳用于记录 .csv 文件何时上传到表格。 那么，如何同时使用当前系统时间戳更新 TimeStamp 列。？请帮忙
公共类 CSVLoader {
private static final
String SQL_INSERT = "INSERT INTO OPPTYMGMT.${table}
(${keys}) VALUES(${values})";
private static final String TABLE_REGEX = "\\$\\{table\\}";
private static final String KEYS_REGEX = "\\$\\{keys\\}";
private static final String VALUES_REGEX = "\\$\\{values\\}";
private Connection connection;
private char seprator;
public CSVLoader(Connection connection) {
this.connection = connection;
//Set default separator
this.seprator = ',';
}
public void loadCSV(String csvFile, String tableName) throws Exception {
CSVReader csvReader = null;
if(null == this.connection) {
throw new Exception("Not a valid connection.");
}
try {
csvReader = new CSVReader(new FileReader(csvFile), this.seprator);
} catch (Exception e) {
e.printStackTrace();
throw new Exception("Error occured while executing file. "
+ e.getMessage());
}
String[] headerRow = csvReader.readNext();
if (null == headerRow) {
throw new FileNotFoundException(
"No columns defined in given CSV file." +
"Please check the CSV file format.");
}
String questionmarks = StringUtils.repeat("?,", headerRow.length);
questionmarks = (String) questionmarks.subSequence(0, questionmarks
.length() - 1);
String query = SQL_INSERT.replaceFirst(TABLE_REGEX, tableName);
query = query
.replaceFirst(KEYS_REGEX, StringUtils.join
(headerRow, ","));
query = query.replaceFirst(VALUES_REGEX, questionmarks);
System.out.println("Query: " + query);
String[] nextLine;
Connection con = null;
PreparedStatement ps = null;
try {
con = this.connection;
con.setAutoCommit(false);
ps = con.prepareStatement(query);
final int batchSize = 1000;
int count = 0;
Date date = null;
while ((nextLine = csvReader.readNext()) != null) {
System.out.println( "inside while" );
if (null != nextLine) {
int index = 1;
for (String string : nextLine) {
date = DateUtil.convertToDate(string);
if (null != date) {
ps.setDate(index++, new java.sql.Date(date
.getTime()));
} else {
ps.setString(index++, string);
System.out.println( "string" +string);
}
}
ps.addBatch();
}
if (++count % batchSize == 0) {
ps.executeBatch();
}
}
ps.executeBatch(); // insert remaining records
con.commit();
} catch (Exception e) {
con.rollback();
e.printStackTrace();
throw new Exception(
"Error occured while loading data
from file to database."
+ e.getMessage());
} finally {
if (null != ps)
ps.close();
if (null != con)
con.close();
System.out.println("csvReader will be closed");
csvReader.close();
}
}
public char getSeprator() {
return seprator;
}
public void setSeprator(char seprator) {
this.seprator = seprator;
}
}
【问题讨论】：
-
通常您在数据库表本身上有一个触发器，它会更新时间戳。这确保了无论哪个软件（甚至是通过 sql 的管理员）更改表，时间戳都是正确的。我不会以任何其他方式实现它......