3. 指出下面程序的运行结果:

class A{
static{
System.out.print("1");
}
public A(){
System.out.print("2");
}
}
class B extends A{
static{
System.out.print("a");
}
public B(){
System.out.print("b");
}
}
public class Hello{
public static void main(String[] ars){
A ab = new B(); //执行到此处,结果: 1a2b
ab = new B(); //执行到此处,结果: 1a2bab
}
}
　　注:类的static 代码段,可以看作是类首次加载(被虚拟机加载)执行的代码,而对于类的加载,首先要执行其基类的构造,再执行其本身的构造

　　4.写一个Singleton模式的例子

public class Singleton{
private static Singleton single = new Singleton();
private Singleton(){}
public Singleton getInstance(){
return single;
}
}
三、数据库

　　1.删除表的重复记录

　　如果记录完全相同才算重复记录,那么: (sql server2000下测试通过)

select distinct * into #tmpp from tid
delete from tid
insert into tid select * from #tmpp
drop table #tmpp
　　如果有id主键(数字,自增1的那种),那么:(sql server2000下测试通过)

delete from tableA where id not in
(select id = min(id) from tableA group by name)
　　2.delete from tablea & truncate table tablea的区别

　　truncate 语句执行速度快,占资源少,并且只记录页删除的日志；
　　delete 对每条记录的删除均需要记录日志


JAVA编程题
1．现在输入n个数字，以逗号，分开；然后可选择升或者降序排序；按提交键就在另一页面显示按什么排序，结果为，提供reset
显示被隐藏内容 import java.util.*;
public class bycomma{
public static String[] splitStringByComma(String source){
if(source==null||source.trim().equals(""))
return null;
StringTokenizer commaToker = new StringTokenizer(source,",");
String[] result = new String[commaToker.countTokens()];
int i=0;
while(commaToker.hasMoreTokens()){
result[i] = commaToker.nextToken();
i++;
}
return result;
}
public static void main(String args[]){
String[] s = splitStringByComma("5,8,7,4,3,9,1");
int[] ii = new int[s.length];
for(int i = 0;i<s.length;i++){
ii[i] =Integer.parseInt(s[i]);
}
Arrays.sort(ii);
//asc
for(int i=0;i<s.length;i++){
System.out.println(ii[i]);
}
//desc
for(int i=(s.length-1);i>=0;i--){
System.out.println(ii[i]);
}
}
}
2．金额转换，阿拉伯数字的金额转换成中国传统的形式如：（￥1011）－>（一千零一拾一元整）输出。
显示被隐藏内容 package test.format;
import java.text.NumberFormat;
import java.util.HashMap;
public class SimpleMoneyFormat {
public static final String EMPTY = "";
public static final String ZERO = "零";
public static final String ONE = "壹";
public static final String TWO = "贰";
public static final String THREE = "叁";
public static final String FOUR = "肆";
public static final String FIVE = "伍";
public static final String SIX = "陆";
public static final String SEVEN = "柒";
public static final String EIGHT = "捌";
public static final String NINE = "玖";
public static final String TEN = "拾";
public static final String HUNDRED = "佰";
public static final String THOUSAND = "仟";
public static final String TEN_THOUSAND = "万";
public static final String HUNDRED_MILLION = "亿";
public static final String YUAN = "元";
public static final String JIAO = "角";
public static final String FEN = "分";
public static final String DOT = ".";

private static SimpleMoneyFormat formatter = null;
private HashMap chineseNumberMap = new HashMap();
private HashMap chineseMoneyPattern = new HashMap();
private NumberFormat numberFormat = NumberFormat.getInstance();

private SimpleMoneyFormat() {
numberFormat.setMaximumFractionDigits(4);
numberFormat.setMinimumFractionDigits(2);
numberFormat.setGroupingUsed(false);

chineseNumberMap.put("0", ZERO);
chineseNumberMap.put("1", ONE);
chineseNumberMap.put("2", TWO);
chineseNumberMap.put("3", THREE);
chineseNumberMap.put("4", FOUR);
chineseNumberMap.put("5", FIVE);
chineseNumberMap.put("6", SIX);
chineseNumberMap.put("7", SEVEN);
chineseNumberMap.put("8", EIGHT);
chineseNumberMap.put("9", NINE);
chineseNumberMap.put(DOT, DOT);

chineseMoneyPattern.put("1", TEN);
chineseMoneyPattern.put("2", HUNDRED);
chineseMoneyPattern.put("3", THOUSAND);
chineseMoneyPattern.put("4", TEN_THOUSAND);
chineseMoneyPattern.put("5", TEN);
chineseMoneyPattern.put("6", HUNDRED);
chineseMoneyPattern.put("7", THOUSAND);
chineseMoneyPattern.put("8", HUNDRED_MILLION);
}

public static SimpleMoneyFormat getInstance() {
if (formatter == null)
formatter = new SimpleMoneyFormat();
return formatter;
}

public String format(String moneyStr) {
checkPrecision(moneyStr);
String result;
result = convertToChineseNumber(moneyStr);
result = addUnitsToChineseMoneyString(result);
return result;
}

public String format(double moneyDouble) {
return format(numberFormat.format(moneyDouble));
}

public String format(int moneyInt) {
return format(numberFormat.format(moneyInt));
}

public String format(long moneyLong) {
return format(numberFormat.format(moneyLong));
}

public String format(Number moneyNum) {
return format(numberFormat.format(moneyNum));
}

private String convertToChineseNumber(String moneyStr) {
String result;
StringBuffer cMoneyStringBuffer = new StringBuffer();
for (int i = 0; i < moneyStr.length(); i++) {
cMoneyStringBuffer.append(chineseNumberMap.get(moneyStr.substring(i, i + 1)));
}
//拾佰仟万亿等都是汉字里面才有的单位，加上它们
int indexOfDot = cMoneyStringBuffer.indexOf(DOT);
int moneyPatternCursor = 1;
for (int i = indexOfDot - 1; i > 0; i--) {
cMoneyStringBuffer.insert(i, chineseMoneyPattern.get(EMPTY + moneyPatternCursor));
moneyPatternCursor = moneyPatternCursor == 8 ? 1 : moneyPatternCursor + 1;
}

String fractionPart = cMoneyStringBuffer.substring(cMoneyStringBuffer.indexOf("."));
cMoneyStringBuffer.delete(cMoneyStringBuffer.indexOf("."), cMoneyStringBuffer.length());
while (cMoneyStringBuffer.indexOf("零拾") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零拾"), cMoneyStringBuffer.indexOf("零拾") + 2, ZERO);
}
while (cMoneyStringBuffer.indexOf("零佰") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零佰"), cMoneyStringBuffer.indexOf("零佰") + 2, ZERO);
}
while (cMoneyStringBuffer.indexOf("零仟") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零仟"), cMoneyStringBuffer.indexOf("零仟") + 2, ZERO);
}
while (cMoneyStringBuffer.indexOf("零万") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零万"), cMoneyStringBuffer.indexOf("零万") + 2, TEN_THOUSAND);
}
while (cMoneyStringBuffer.indexOf("零亿") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零亿"), cMoneyStringBuffer.indexOf("零亿") + 2, HUNDRED_MILLION);
}
while (cMoneyStringBuffer.indexOf("零零") != -1) {
cMoneyStringBuffer.replace(cMoneyStringBuffer.indexOf("零零"), cMoneyStringBuffer.indexOf("零零") + 2, ZERO);
}
if (cMoneyStringBuffer.lastIndexOf(ZERO) == cMoneyStringBuffer.length() - 1)
cMoneyStringBuffer.delete(cMoneyStringBuffer.length() - 1, cMoneyStringBuffer.length());
cMoneyStringBuffer.append(fractionPart);

result = cMoneyStringBuffer.toString();
return result;
}


private String addUnitsToChineseMoneyString(String moneyStr) {
String result;
StringBuffer cMoneyStringBuffer = new StringBuffer(moneyStr);
int indexOfDot = cMoneyStringBuffer.indexOf(DOT);
cMoneyStringBuffer.replace(indexOfDot, indexOfDot + 1, YUAN);