1. 字符串有整型的相互转换
Stringa = 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= newBufferedWriter(newFileWriter(”filename”, true));
out.write(”aString”);
} catch(IOException e) {
// error processing code
} finally{
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if(out!= null) {
out.close();
}
}
3. 得到当前方法的名字
StringmethodName = 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 = newSimpleDateFormat( "yyyy-MM-dd");
Datedate = format.parse( myString );
5. 使用JDBC链接Oracle
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.列出文件和目录
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.解析/读取XML 文件
<?xml version="1.0"?>
John
B
12
Mary
A
11
Simon
A
18
8.java分页代码实现
publicclassPageBean{
privateintcurPage; //当前页
privateintpageCount; //总页数
privateintrowsCount; //总行数
privateintpageSize=10; //每页多少行
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;
}
}
分页展示如下
List clist=adminbiz.queryNotFullCourse();//将查询结果存放在List集合里
PageBean pagebean=newPageBean(clist.size());//初始化PageBean对象
//设置当前页
pagebean.setCurPage(page); //这里page是从页面上获取的一个参数，代表页数
//获得分页大小
intpagesize=pagebean.getPageSize();
//获得分页数据在list集合中的索引
intfirstIndex=(page-1)*pagesize;
inttoIndex=page*pagesize;
if(toIndex>clist.size()){
toIndex=clist.size();
}
if(firstIndex>toIndex){
firstIndex=0;
pagebean.setCurPage(1);
}
//截取数据集合，获得分页数据
List courseList=clist.subList(firstIndex, toIndex);
