1. 字符串有整型的相互转换
- String a = String.valueOf(2); //integer to numeric string
- int i = Integer.parseInt(a); //numeric string to an int
2. 向文件末尾添加内容
- BufferedWriter out = null;
- try {
- out = new BufferedWriter(new FileWriter(”filename”, true));
- out.write(”aString”);
- } catch (IOException e) {
- // error processing code
- } finally {
- if (out != null) {
- out.close();
- }
- }
3. 得到当前方法的名字
- String methodName = Thread.currentThread().getStackTrace()[1].getMethodName();
4. 转字符串到日期
- java.util.Date = java.text.DateFormat.getDateInstance().parse(date String);
或者是：
- SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );
- Date date = format.parse( myString );
5. 使用JDBC链接Oracle
- public class OracleJdbcTest
- {
- String driverClass = "oracle.jdbc.driver.OracleDriver";
-
- Connection con;
-
- public void init(FileInputStream fs) throws ClassNotFoundException, SQLException, FileNotFoundException, IOException
- {
- Properties props = new Properties();
- props.load(fs);
- String url = props.getProperty("db.url");
- String userName = props.getProperty("db.user");
- String password = props.getProperty("db.password");
- Class.forName(driverClass);
-
- con=DriverManager.getConnection(url, userName, password);
- }
-
- public void fetch() throws SQLException, IOException
- {
- PreparedStatement ps = con.prepareStatement("select SYSDATE from dual");
- ResultSet rs = ps.executeQuery();
-
- while (rs.next())
- {
- // do the thing you do
- }
- rs.close();
- ps.close();
- }
-
- public static void main(String[] args)
- {
- OracleJdbcTest test = new OracleJdbcTest();
- test.init();
- test.fetch();
- }
- }
6. 把 Java util.Date 转成 sql.Date
- java.util.Date utilDate = new java.util.Date();
- java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());
7. 使用NIO进行快速的文件拷贝
- public static void fileCopy( File in, File out )
- throws IOException
- {
- FileChannel inChannel = new FileInputStream( in ).getChannel();
- FileChannel outChannel = new FileOutputStream( out ).getChannel();
- try
- {
- // inChannel.transferTo(0, inChannel.size(), outChannel); // original -- apparently has trouble copying large files on Windows
-
- // magic number for Windows, 64Mb - 32Kb)
- int maxCount = (64 * 1024 * 1024) - (32 * 1024);
- long size = inChannel.size();
- long position = 0;
- while ( position < size )
- {
- position += inChannel.transferTo( position, maxCount, outChannel );
- }
- }
- finally
- {
- if ( inChannel != null )
- {
- inChannel.close();
- }
- if ( outChannel != null )
- {
- outChannel.close();
- }
- }
- }
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2013-6-18 14:57:40 |
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