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( "yyyy-MM-dd" ); 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.列出文件和目录
File dir = new File("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 String filename = 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 = new FilenameFilter() { public boolean
accept(File dir, String name) { 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 = new FileFilter() { public boolean accept(File file) {
return file.isDirectory(); } }; files = dir.listFiles(fileFilter);
7.解析/读取XML 文件
<?xml version="1.0"?> <students> <student> <name>John</name> <grade>B</grade>
<age>12</age> </student> <student> <name>Mary</name> <grade>A</grade>
<age>11</age> </student> <student> <name>Simon</name> <grade>A</grade>
<age>18</age> </student> </students>
8.java分页代码实现
1 public class PageBean { 2 private int curPage; //当前页 3 private int
pageCount; //总页数 4 private int rowsCount; //总行数 5 private int pageSize=10;
//每页多少行 6 7 8 9 public PageBean(int rows){ 10 11 this.setRowsCount(rows); 12
if(this.rowsCount % this.pageSize == 0){ 13 this.pageCount=this.rowsCount /
this.pageSize; 14 } 15 else if(rows<this.pageSize){ 16 this.pageCount=1; 17 }
18 else{ 19 this.pageCount=this.rowsCount / this.pageSize +1; 20 } 21 } 22 23
24 public int getCurPage() { 25 return curPage; 26 } 27 public void
setCurPage(int curPage) { 28 this.curPage = curPage; 29 } 30 public int
getPageCount() { 31 return pageCount; 32 } 33 public void setPageCount(int
pageCount) { 34 this.pageCount = pageCount; 35 } 36 public int getPageSize() {
37 return pageSize; 38 } 39 public void setPageSize(int pageSize) { 40
this.pageSize = pageSize; 41 } 42 public int getRowsCount() { 43 return
rowsCount; 44 } 45 public void setRowsCount(int rowsCount) { 46 this.rowsCount
= rowsCount; 47 } 48 }
分页展示如下
1 List clist=adminbiz.queryNotFullCourse();//将查询结果存放在List集合里 2 PageBean
pagebean=new PageBean(clist.size());//初始化PageBean对象 3 //设置当前页 4
pagebean.setCurPage(page); //这里page是从页面上获取的一个参数,代表页数 5 //获得分页大小 6 int
pagesize=pagebean.getPageSize(); 7 //获得分页数据在list集合中的索引 8 int
firstIndex=(page-1)*pagesize; 9 int toIndex=page*pagesize; 10
if(toIndex>clist.size()){ 11 toIndex=clist.size(); 12 } 13
if(firstIndex>toIndex){ 14 firstIndex=0; 15 pagebean.setCurPage(1); 16 } 17
//截取数据集合,获得分页数据 18 List courseList=clist.subList(firstIndex, toIndex);
 

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