Common Java codebase Summary

1. Conversion of string and integer types to each other

String a= string.valueof (2); int i = Integer.parseint (a);

2. Add content to the end of the file

BufferedWriter out=null;try {out=new bufferedwriter (new FileWriter ("filename", true)); Out.write ("I am stringbuffer!");} catch (IOException e) {e.printstacktrace ();}

3. Get the name of the current method

String methodName = Thread.CurrentThread (). Getstacktrace () [1].getmethodname ();

4. Turn string to date and date to string

Date to string SimpleDateFormat SDF = new SimpleDateFormat ("yyyy mm month DD day");     String str = sdf.format (new Date ());     System.out.println (str);     The string to the date of day     : date = Sdf.parse (str);     SYSTEM.OUT.PRINTLN (date);

5. Using JDBC to link 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 ("Selec          T sysdate from dual ");            ResultSet rs = Ps.executequery ();          while (Rs.next ()) {//Does the thing you do} rs.close ();      Ps.close ();    } public static void Main (string[] args) {oraclejdbctest test = new Oraclejdbctest ();      Test.init ();      Test.fetch (); } }

6. Util Java. Date turns into SQL. Date

Java.util.Date utildate = new Java.util.Date ();  Java.sql.Date sqldate = new Java.sql.Date (Utildate.gettime ());

7. Fast file copy using NiO

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 have 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 (); }          }      }

  8 . list files and directories

Import Java.io.file;import Java.io.filefilter;import Java.io.filenamefilter;public class Test {public static void main (    String[] args) {file Dir = new File ("f:\\ Hanshunping java");   String[] Children = dir.list (); if (children = = null) {//either Dir does not exist or was not a directory} else {for (int i=0; i < Children.length;            i++) {//Get filename of file or directory String filename = children[i];      System.out.println (i+ "---" +filename);    }}//It is also possible to filter the list of returned files.    This example does no return any files that start with '. '. FilenameFilter filter = new FilenameFilter () {public Boolean accept (File dir, String name) {return!na        Me.startswith (".");    }    };    Children = dir.list (filter);      The list of files can also be retrieved as File objects file[] files = dir.listfiles (); This filter is only returns directories FileFilter FileFilter = New FileFilter () {public boolean accept (file file) {return file.isdirectory ();    }    }; Files = dir.listfiles (FileFilter);} }

9. HTTP request to send generation data

try {              url my_url = new URL ("link address");              BufferedReader br = new BufferedReader (New InputStreamReader (My_url.openstream ()));              String strtemp = "";              while (null! = (strtemp = Br.readline ())) {              System.out.println (strtemp);          }          } catch (Exception ex) {              Ex.printstacktrace ();          

　　

Common Java codebase Summary