1. There integer string conversion
Stringa = String.valueOf(2); //integer to numeric string
int i = Integer.parseInt(a); //numeric string to an int
2. Add content to the end of the file
BufferedWriter out= null;
try{
out= newBufferedWriter(newFileWriter(”filename”, true));
out.write(”aString”);
} catch(IOException e) {
// error processing code
} finally{
if(out!= null) {
out.close();
}
}
3. Get the name of the current method of
StringmethodName = Thread.currentThread().getStackTrace()[1].getMethodName();
4. The date to String
java.util.Date = java.text.DateFormat.getDateInstance().parse(date String);
or:
SimpleDateFormat format = newSimpleDateFormat( "yyyy-MM-dd");
Datedate = format.parse( myString );
5. Use the Oracle JDBC link
publicclassOracleJdbcTest
{
String driverClass = "oracle.jdbc.driver.OracleDriver";
Connection con;
publicvoidinit(FileInputStream fs)throwsClassNotFoundException, SQLException, FileNotFoundException, IOException
{
Properties props = newProperties();
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);
}
publicvoidfetch()throwsSQLException, 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();
}
publicstaticvoidmain(String[] args)
{
OracleJdbcTest test = newOracleJdbcTest();
test.init();
test.fetch();
}
}
6. List files and directories
File dir = newFile("directoryName");
String[] children = dir.list();
if(children == null) {
// Either dir does not exist or is not a directory
} else{
for(int i=0; i < children.length; i++) {
// Get filename of file or directory
Stringfilename = children[i];
}
}
// It is also possible to filter the list of returned files.
// This example does not return any files that start with `.'.
FilenameFilter filter = newFilenameFilter() {
publicbooleanaccept(File dir, Stringname) {
return!name.startsWith(".");
}
};
children = dir.list(filter);
// The list of files can also be retrieved as File objects
File[] files = dir.listFiles();
// This filter only returns directories
FileFilter fileFilter = newFileFilter() {
publicbooleanaccept(File file) {
returnfile.isDirectory();
}
};
files = dir.listFiles(fileFilter);
7. parsing / reading an XML file
<?xml version="1.0"?>
John
B
12
Mary
A
11
Simon
A
18
8.java paging code implementation
publicclassPageBean {
privateintcurPage; // this page
privateintpageCount; // total number of pages
privateintrowsCount; // total number of rows
privateintpageSize = 10; // how many rows per page
publicPageBean(introws){
this.setRowsCount(rows);
if(this.rowsCount % this.pageSize == 0){
this.pageCount=this.rowsCount / this.pageSize;
}
elseif(rows
this.pageCount=1;
}
else{
this.pageCount=this.rowsCount / this.pageSize +1;
}
}
publicintgetCurPage(){
returncurPage;
}
publicvoidsetCurPage(intcurPage){
this.curPage = curPage;
}
publicintgetPageCount () {
returnpageCount;
}
publicvoidsetPageCount(intpageCount){
this.pageCount = pageCount;
}
publicintgetPageSize () {
returnpageSize;
}
publicvoidsetPageSize(intpageSize){
this.pageSize = pageSize;
}
publicintgetRowsCount () {
returnrowsCount;
}
publicvoidsetRowsCount(introwsCount){
this.rowsCount = rowsCount;
}
}
Paging is shown below
List clist = adminbiz.queryNotFullCourse (); // query results stored in the collection List
PageBean pagebean = newPageBean (clist.size ()); // initialize objects PageBean
// Set the current page
pagebean.setCurPage (page); // this page is taken from the page of a parameter representative of the number of pages
// Get the page size
intpagesize=pagebean.getPageSize();
// get the index page in the list of data collection
intfirstIndex=(page-1)*pagesize;
inttoIndex=page*pagesize;
if(toIndex>clist.size()){
toIndex=clist.size();
}
if(firstIndex>toIndex){
firstIndex=0;
pagebean.setCurPage(1);
}
// intercept the data set, the data obtained tab
List courseList=clist.subList(firstIndex, toIndex);
