Java基础中用到的代码片段
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( \ ); Date date = format.parse( myString );
5. 使用JDBC链接Oracle
public class OracleJdbcTest
{
String driverClass = \;
Connection con;
public void init(FileInputStream fs) throws ClassNotFoundException, SQLException, FileNotFoundException, IOException {
Properties props = new Properties(); props.load(fs);
String url = props.getProperty(\); String userName = props.getProperty(\); String password = props.getProperty(\); Class.forName(driverClass);
con=DriverManager.getConnection(url, userName, password); }
public void fetch() throws SQLException, IOException {
PreparedStatement ps = con.prepareStatement(\ 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 );