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1.將ibatis 的jar 包添加到工程中
2.先新建一個(gè)xml文件 SqlMap.xml,在這個(gè)文件中定義使用了哪些ibatis資源文件
<?xml version="1.0" encoding="gb2312"?>
<!DOCTYPE sql-map-config PUBLIC "-//iBATIS.com//DTD SQL Map Config 1.0//EN"
"<sql-map-config>
<sql-map resource="com/montersoft/ibatis/common/monter.xml"/>
</sql-map-config>
3.定義資源文件monter.xml
<?xml version="1.0" encoding="gb2312"?>
<!DOCTYPE sql-map
PUBLIC "-//iBATIS.com//DTD SQL Map 1.0//EN"
"<sql-map name="monter">
<result-map name="monterInfo" class="java.util.HashMap">
<property name="id" column="id" type="VARCHAR"/>
<property name="name" column="name" type="VARCHAR"/>
<property name="age" column="age" type="NUMBERIC"/>
</result-map>
<dynamic-mapped-statement name="monter_getByPk" result-map="monterInfo">
select id,name,age from monter where id = #id#
</dynamic-mapped-statement>
</sql-map>
**注意dynamic-mapped-statement的name 必須唯一
4.定義一個(gè)公共類來生成SqlMap
package com.montersoft.ibatis.common;
import java.io.Reader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.ibatis.common.resources.Resources;
import com.ibatis.db.sqlmap.SqlMap;
import com.ibatis.db.sqlmap.XmlSqlMapBuilder;
public class SqlMapUtil {
private static Log loger = LogFactory.getLog(SqlMapUtil.class);
public static SqlMap sqlMap ;
public static SqlMap loadSqlMap(){
Reader reader = null;
try{
reader = Resources.getResourceAsReader("com/montersoft/ibatis/common/SqlMap.xml");
return XmlSqlMapBuilder.buildSqlMap(reader);
}
catch(Exception e){
loger.error("there is a error=>"+e.getMessage());
}
return null;
}
public static SqlMap getSqlMap(){
if( sqlMap == null )
sqlMap = loadSqlMap();
return sqlMap;
}
}
5.再新建DAO,Vo,
public interface IVO {
}
public class MonterVo implements IVO{
public String id ;
public String name;
public int age;
...省去 get ,set 方法
}
public class MonterDao {
public IVO getBkPK(Connection conn,IVO vo) throws Exception{
try{
Object map = SqlMapUtil.getSqlMap().
getMappedStatement("monter_getByPk").executeQueryForObject(conn,vo);
return copyMap2Vo(map);
}
catch(Exception e){
throw new Exception(e.getMessage());
}
}
private IVO copyMap2Vo(Object map){
MonterVo vo = new MonterVo();
try{
BeanUtils.copyProperties(vo,map);
}
catch(Exception e){
e.printStackTrace();
}
return vo;
}
}
6.至此就建立了一個(gè)簡單的ibatis示例.
通過weblogic的數(shù)據(jù)源獲得數(shù)據(jù)庫連接的方法:
package com.moonsoft.datasource;
import javax.naming.NamingException;
import java.util.Hashtable;
import javax.naming.InitialContext;
import java.sql.Connection;
import javax.sql.DataSource;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class TestDataSource {
public static String WEB_URL = "t3://localhost:9000";
public static String DATA_SOURCE = "JDBCDS";
public static String weblogic_context_factory =
"weblogic.jndi.WLInitialContextFactory";
public TestDataSource() {
}
public static Object lookUp() throws NamingException {
Hashtable env = new Hashtable();
env.put(InitialContext.INITIAL_CONTEXT_FACTORY, weblogic_context_factory);
env.put(InitialContext.PROVIDER_URL, WEB_URL);
InitialContext tempContext = new InitialContext(env);
return tempContext.lookup(DATA_SOURCE);
}
public static Connection getConnection() throws SQLException {
Connection conn = null;
try {
DataSource ds = (DataSource) lookUp();
if (ds == null) {
throw new SQLException("查詢到空數(shù)據(jù)源!");
}
conn = ds.getConnection();
}
catch (NamingException ex) {
ex.printStackTrace();
}
return conn;
}
public static void releaseConnection(Connection conn, PreparedStatement sta,
ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
if (sta != null)
sta.close();
if (conn != null)
conn.close();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
public static void testSearch() {
Connection conn = null;
PreparedStatement sta = null;
ResultSet rs = null;
try {
conn = getConnection();
String sql = "select * from admin_config where config_name like ?";
sta = conn.prepareStatement(sql);
sta.setString(1,"%Sms%");
rs = sta.executeQuery();
if (rs != null) {
while (rs.next()) {
System.out.println(rs.getString(1));
}
}
}
catch (Exception ex) {
ex.printStackTrace();
}
finally {
releaseConnection(conn,sta,rs);
}
}
public static void main(String [] argv){
testSearch();
}
}
如果是在需求還沒確定或者是在兩個(gè)類實(shí)現(xiàn)相近功能時(shí)候，會(huì)大量使用下面的方式:
--抽象類,注意其中的newInstance方法的實(shí)現(xiàn)
package com.moonsoft.design;
public abstract class Moon {
public static Moon newInstance(String classStr){
Class re;
try {
re = Class.forName(classStr);
return (Moon)re.newInstance();
}
catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public abstract void println();
}
--從Moon類派生出來的一個(gè)字類，提供println方法的一種實(shí)現(xiàn)方式
package com.moonsoft.design;
public class Moon1 extends Moon {
public void println(){
System.out.println("I am moon1");
}
public void myprintln(){
System.out.println("I am moon1 myprintln");
}
}
--從Moon類派生出來的另一個(gè)字類，提供println方法的另一種實(shí)現(xiàn)方式
package com.moonsoft.design;
public class Moon2 extends Moon {
public void println(){
System.out.println("I am moon2!");
}
}
--調(diào)用
Moon moon = Moon.newInstance("com.moonsoft.design.Moon1");
moon.println();
或
Moon moon = Moon.newInstance("com.moonsoft.design.Moon2");
moon.println();
如要在JSP頁面上有一個(gè)鏈接，Url值是通過參數(shù)輸入的,用JSP標(biāo)簽的實(shí)現(xiàn)步驟(當(dāng)然實(shí)際中不會(huì)用標(biāo)簽來完成這么簡單的功能):
<一>.先從javax.servlet.jsp.tagext.BodyTagSupport派生一個(gè)新的類，并重載它的doStartTag()方法.如果是想要傳入?yún)?shù)的話，則還要在Bean中加入想要的變量，如這里要傳入一個(gè)url值，所以添加一個(gè)參數(shù):linkUrl. 最后代碼如下:
package com.moonsoft.jsptag;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.JspException;
public class UrlLinkTag extends BodyTagSupport {
private String linkUrl;
public UrlLinkTag() {
}
public String getLinkUrl() {
return linkUrl;
}
public void setLinkUrl(String linkUrl) {
this.linkUrl = linkUrl;
}
public int doStartTag() throws JspException{
try {
this.pageContext
.getOut().print("<a href=\'"+linkUrl+"\' >"+linkUrl+"</a>");
}
catch (Exception ex) {
ex.printStackTrace();
}
return 0;
}
}
<二>新建一個(gè)tld文件,內(nèi)容如下:
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
" <taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.1</jspversion>
<shortname>buttons</shortname>
<uri>http://www.borland.com/jbuilder/internetbeans.tld</uri>
<info>
JSP tag extensions for InternetBeans Express
</info>
<tag>
<name>urllink</name>
<tagclass>com.moonsoft.jsptag.UrlLinkTag</tagclass>
<bodycontent>jsp</bodycontent>
<attribute>
<name>linkUrl</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
<三>在web.xml中引入這個(gè)taglib,在其中加入:
<taglib>
<taglib-uri>/moon</taglib-uri>
<taglib-location>/WEB-INF/classes/com/moonsoft/jsptag/UrlLinkTag.tld</taglib-location>
</taglib>
<四>在jsp中引入這個(gè)標(biāo)簽
<%@ taglib uri="/moon" prefix="mylinkurl" %>
這里uri是和web.xml中配置的taglib-uri對(duì)應(yīng)的，prefix值只是在本jsp頁面作為標(biāo)示用.
下面就可以在jsp中使用這個(gè)標(biāo)簽了:
<mylinkurl:urllink linkUrl="
這里面的mylinkurl為在本jsp頁面中設(shè)置的prefix值，urllink為tld文件中tag name,linkUrl為輸入的參數(shù)
這樣就在jsp頁面上加入了一個(gè):
<a >http://www.baidu.com</a>鏈接
現(xiàn)在正在做的項(xiàng)目中涉及大量的Excel文件導(dǎo)出導(dǎo)入操作,都是使用Java Excel來操作。
Java Excel是一開放源碼項(xiàng)目，通過它Java開發(fā)人員可以讀取Excel文件的內(nèi)容、創(chuàng)建新的Excel文件、更新已經(jīng)存在的Excel文件。下面我寫了一個(gè)簡單的例子，展示基本的讀取，新建，更新(包括常見格式的設(shè)置:字體，顏色，背景,合并單元格)，拷貝操作，有這些其實(shí)已經(jīng)基本足夠應(yīng)付大部分問題了。下面是例的源代碼:
import java.io.*;
import java.util.Date;
import jxl.*;
import jxl.format.Colour;
import jxl.format.UnderlineStyle;
import jxl.read.biff.BiffException;
import jxl.write.*;
import jxl.format.UnderlineStyle;
import jxl.format.CellFormat;;
public class OperateExcel {
/**
* Read data from a excel file
*/
public static void readExcel(String excelFileName){
Workbook rwb = null;
try{
InputStream stream = new FileInputStream(excelFileName);
rwb = Workbook.getWorkbook(stream);
Sheet sheet = rwb.getSheet(0);
Cell cell = null;
int columns = sheet.getColumns();
int rows = sheet.getRows();
for( int i=0 ; i< rows ; i++ )
for( int j=0 ; j< columns ; j++){
//attention: The first parameter is column,the second parameter is row.
cell = sheet.getCell(j,i);
String str00 = cell.getContents();
if( cell.getType() == CellType.LABEL )
str00 += " LAEBL";
else if( cell.getType() == CellType.NUMBER)
str00 += " number";
else if( cell.getType() == CellType.DATE)
str00 += " date";
System.out.println("00==>"+str00);
}
stream.close();
}
catch(IOException e){
e.printStackTrace();
}
catch(BiffException e){
e.printStackTrace();
}
finally{
rwb.close();
}
}
/**
* create a new excelFile
* @param excelFileName create name
*/
public static void createExcelFile(String excelFileName){
try{
WritableWorkbook wwb = Workbook.createWorkbook(new File(excelFileName));
WritableSheet ws = wwb.createSheet("sheet1",0);
//also,The first parameter is column,the second parameter is row.
// add normal label data
Label label00 = new Label(0,0,"Label00");
ws.addCell(label00);
//add font formating data
WritableFont wf = new WritableFont(WritableFont.TIMES, 18, WritableFont.BOLD , true);
WritableCellFormat wff = new WritableCellFormat(wf);
Label label10 = new Label(1,0,"Label10",wff);
ws.addCell(label10);
//add color font formating data
WritableFont wf_color = new WritableFont(WritableFont.ARIAL,10,WritableFont.NO_BOLD,false,UnderlineStyle.DOUBLE_ACCOUNTING,Colour.RED);
WritableCellFormat wff_color = new WritableCellFormat(wf_color);
wff_color.setBackground(Colour.GRAY_25); //set background coloe to gray
Label label20 = new Label(2,0,"Label20",wff_color);
ws.addCell(label20);
//合并單元格
WritableFont wf_merge = new WritableFont(WritableFont.ARIAL,10,WritableFont.NO_BOLD,false,UnderlineStyle.DOUBLE_ACCOUNTING,Colour.GREEN);
WritableCellFormat wff_merge = new WritableCellFormat(wf_merge);
wff_merge.setBackground(Colour.BLACK);
Label label30 = new Label(3,0,"Label30",wff_merge);
ws.addCell(label30);
Label label40 = new Label(4,0,"Label40");
ws.addCell(label40);
Label label50 = new Label(5,0,"Label50");
ws.addCell(label50);
//合并 (0,3) (4,0)
//attention : 如果合并后面的列不為空,那么就把后面格的內(nèi)容清空,格式也是按前一個(gè)單元格的格式
ws.mergeCells(3,0,4,0);
//添加Number格式數(shù)據(jù)
jxl.write.Number labelN = new jxl.write.Number(0, 1, 3.1415926);
ws.addCell(labelN);
//添加帶有formatting的Number對(duì)象
jxl.write.NumberFormat nf = new jxl.write.NumberFormat("#.##");
jxl.write.WritableCellFormat wcfN = new jxl.write.WritableCellFormat(nf);
jxl.write.Number labelNF = new jxl.write.Number(1, 1, 3.1415926, wcfN);
ws.addCell(labelNF);
//添加Boolean對(duì)象
jxl.write.Boolean labelBoolean = new jxl.write.Boolean(2,1,false);
ws.addCell(labelBoolean);
//添加DateTime對(duì)象
DateTime labelDT = new DateTime(3,1,new Date());
ws.addCell(labelDT);
//添加帶有格式的DataTime數(shù)據(jù)
DateFormat dtf = new DateFormat("yyyy-MM-dd hh:mm:ss");
WritableCellFormat wcfDt = new WritableCellFormat(dtf);
wcfDt.setBackground(Colour.YELLOW);
DateTime labelDT_format = new DateTime(4,1,new java.util.Date(),wcfDt);
ws.addCell(labelDT_format);
ws.mergeCells(4,1,5,1); //比較長,用兩列來顯示
wwb.write();
wwb.close();
}
catch(IOException e){
e.printStackTrace();
}
catch(WriteException e){
e.printStackTrace();
}
}
/**
* 如何更新Excel文件
* @param fileName
*/
public static void updateExcel(String fileName){
try{
jxl.Workbook rw = jxl.Workbook.getWorkbook(new File(fileName));
WritableWorkbook wwb = Workbook.createWorkbook(new File(fileName),rw);
//這里其實(shí)執(zhí)行的是一次copy操作,把文件先讀到內(nèi)存中,修改后再保存覆蓋原來的文件來實(shí)現(xiàn)update操作
WritableSheet ws = wwb.getSheet(0);
WritableCell wc = ws.getWritableCell(0,0);
if( wc.getType() == CellType.LABEL){
Label l = (Label)wc;
l.setString(wc.getContents()+"_new");
}
wwb.write();
wwb.close();
}
catch(IOException e){
e.printStackTrace();
}
catch(WriteException e){
e.printStackTrace();
}
catch(BiffException e){
e.printStackTrace();
}
}
/**
* 如何copy Excel文件
* @param fileName
*/
public static void copyExcel(String sourFileName,String destFileName){
try{
jxl.Workbook rw = jxl.Workbook.getWorkbook(new File(sourFileName));
WritableWorkbook wwb = Workbook.createWorkbook(new File(destFileName),rw);
wwb.write();
wwb.close();
}
catch(IOException e){
e.printStackTrace();
}
catch(WriteException e){
e.printStackTrace();
}
catch(BiffException e){
e.printStackTrace();
}
}
public static void main(String [] argv){
//OperateExcel.readExcel("E:\\test.xls");
//OperateExcel.createExcelFile("E:\\test1.xls");
//OperateExcel.updateExcel("E:\\test.xls");
OperateExcel.copyExcel("E:\\test.xls","E:\\moon.xls");
}
}
在編程中可能回碰到一些到實(shí)際運(yùn)行時(shí)才指定要調(diào)用的方法的需要，最典型的是Struct的DispatchAction類，
它能根據(jù)用戶頁面請(qǐng)求參數(shù)的不同來調(diào)用不同的方法來處理用戶請(qǐng)求。我下面寫了一個(gè)簡單的例子來簡單演示其
實(shí)現(xiàn)方法:
package learn;
import java.lang.NoSuchMethodException;
import java.lang.reflect.Method;
import java.util.Date;
public class TestMethod{
protected Class clazz = this.getClass();
protected Class[] no_parameter = {}; //方法無參數(shù)
protected Class[] string_parameter = {String.class}; //以String 為參數(shù)
protected Class[] int_parameter = {int.class}; //以int為參數(shù)
protected Class[] multi_parameter = {String.class,Date.class}; //多個(gè)參數(shù),第一個(gè)為String,第二二個(gè)為Date
public void method1(){
System.out.println("method1");
}
public void method2(String str){
System.out.println("method2=>"+str);
}
public void method3(int i){
System.out.println("method2=>"+i);
}
public void method4(String str,Date date){
System.out.println("method4=>"+str+"==="+date.toLocaleString());
}
public void execute(String methodName,int type,java.util.List list) throws Exception{
try {
Method m = getMethod(methodName,type);
int size = (list != null )? list.size():0;
Object o [] = new Object[size];
for( int i =0 ; i< size ; i++ )
o[i] = list.get(i); //準(zhǔn)備參數(shù)
m.invoke(this,o);
}
catch (Exception ex) {
ex.printStackTrace();
throw new Exception(ex.getMessage());
}
}
private Method getMethod(String name,int type)throws NoSuchMethodException{
Method m = null;
switch(type){
case 1:
m = clazz.getMethod(name,no_parameter);
break;
case 2:
m = clazz.getMethod(name,string_parameter);
break;
case 3:
m = clazz.getMethod(name,int_parameter);
break;
case 4:
m = clazz.getMethod(name,multi_parameter);
break;
default:
m = clazz.getMethod(name,no_parameter);
}
return m;
}
public static void main(String [] argv){
TestMethod testMethod = new TestMethod();
try{
java.util.List list = new java.util.ArrayList();
testMethod.execute("method1", 1, list);
list.add("http://www.aygfsteel.com/minmoon");
testMethod.execute("method2", 2, list);
list.clear();
list.add("mailTo:xiaoliang@aspire-tech.com");
list.add(new Date());
testMethod.execute("method4",4,list);
}
catch(Exception e){
e.printStackTrace();
}
}
}
其中幾個(gè)關(guān)鍵的地方說明一下:
clazz.getMethod(name,multi_parameter); 其中multi_parameter是要根據(jù)實(shí)際方法的參數(shù)來定義的。
m.invoke(this,o); o是要傳入方法的參數(shù)列表。
原型模式定義:
用原型實(shí)例指定創(chuàng)建對(duì)象的種類,并且通過拷貝這些原型創(chuàng)建新的對(duì)象.
Prototype模式允許一個(gè)對(duì)象再創(chuàng)建另外一個(gè)可定制的對(duì)象，根本無需知道任何如何創(chuàng)建的細(xì)節(jié),工作原理是:通過將一個(gè)原型對(duì)象傳給那個(gè)要發(fā)動(dòng)創(chuàng)建的對(duì)象，這個(gè)要發(fā)動(dòng)創(chuàng)建的對(duì)象通過請(qǐng)求原型對(duì)象拷貝它們自己來實(shí)施創(chuàng)建。
如何使用?
因?yàn)镴ava中的提供clone()方法來實(shí)現(xiàn)對(duì)象的克隆,所以Prototype模式實(shí)現(xiàn)一下子變得很簡單.
以勺子為例：
public abstract class AbstractSpoon implements Cloneable
{
String spoonName;
public void setSpoonName(String spoonName) {this.spoonName = spoonName;}
public String getSpoonName() {return this.spoonName;}
public Object clone()
{
Object object = null;
try {
object = super.clone();
} catch (CloneNotSupportedException exception) {
System.err.println("AbstractSpoon is not Cloneable");
}
return object;
}
}
|
有個(gè)具體實(shí)現(xiàn)(ConcretePrototype):
|
public class SoupSpoon extends AbstractSpoon
{
public SoupSpoon()
{
setSpoonName("Soup Spoon");
}
}
|
調(diào)用Prototype模式很簡單:
AbstractSpoon spoon = new SoupSpoon();
AbstractSpoon spoon2 = spoon.clone();
當(dāng)然也可以結(jié)合工廠模式來創(chuàng)建AbstractSpoon實(shí)例。
在Java中Prototype模式變成clone()方法的使用，由于Java的純潔的面向?qū)ο筇匦裕沟迷贘ava中使用設(shè)計(jì)模式變得很自然，兩者已經(jīng)幾乎是渾然一體了。這反映在很多模式上，如Interator遍歷模式。
原文出處:http://www.jdon.com/designpatterns/prototype.htm
看看寫的很好,就拿來引用一下,不用自己寫的那么累^_^.
Factory method,工廠方法模式，定義一個(gè)用于創(chuàng)建對(duì)象的接口，讓字類決定實(shí)例化哪一個(gè)類。也就是使一個(gè)類的實(shí)例化延遲到其子類，提供一種方法使對(duì)象創(chuàng)建變得多態(tài)。
下面是我寫的一個(gè)例子，如有兩種工人，car worker和bus worker,所生成的產(chǎn)品分別是car 和 bus,我按照Factory method 的實(shí)現(xiàn)如下:
--先定義car 和 bus 的父類，都是一種產(chǎn)品
package Factory;
public class Product {
public void whoami(){
System.out.println("I am a product!");
}
}
--Car 類
package Factory;
public class Car extends Product {
public Car() {
}
public void whoami(){
System.out.println("I am a car!");
}
}
--Bus 類
package Factory;
public class Bus extends Product {
public Bus() {
}
public void whoami(){
System.out.println("I am a bus!");
}
}
--定義CarWorker和BusWorker的父類 worker
package Factory;
public abstract class Worker {
private Product theProduct;
public abstract Product createProduct();
public void work(){
theProduct = createProduct();
}
public void showMessage(){
this.theProduct.whoami();
}
}
--Carworker
package Factory;
public class CarWorker extends Worker {
public Product createProduct(){
return new Car();
}
}
--BusWorker
package Factory;
public class BusWorker extends Worker {
public Product createProduct(){
return new Bus();
}
}
--下面看看具體的調(diào)用
package Factory;
public class TestAll {
public static void main(String [] argv){
Worker worker = new CarWorker();
worker.work();
worker.showMessage();
Worker worker1 = new BusWorker();
worker1.work();
worker1.showMessage();
}
}
可以看到雖然這樣實(shí)現(xiàn)有一些麻煩，如新加一種產(chǎn)品時(shí)，就必須從Product類創(chuàng)建一個(gè)子類，但是這樣做的
好處也是顯而易見的，會(huì)給你系統(tǒng)帶來更大的可擴(kuò)展性和盡量少的修改量,再添加一種產(chǎn)品一種工人的時(shí)候，對(duì)以前的代碼是不必做任何修改的。
<個(gè)人觀點(diǎn)，僅作參考>
Singleton模式為單態(tài)模式或者叫孤子模式,保證一個(gè)類只有一個(gè)實(shí)例，并提供一個(gè)訪問它的全局訪問點(diǎn)。
Singleton模式的使用范圍比較廣泛，對(duì)于一些類來說，只有一個(gè)實(shí)例是很重要的。比如，你要論壇中
的帖子計(jì)數(shù)器，每次瀏覽一次需要計(jì)數(shù)，單態(tài)類能否保持住這個(gè)計(jì)數(shù)，并且能synchronize的安全自動(dòng)加
1，如果你要把這個(gè)數(shù)字永久保存到數(shù)據(jù)庫，你可以在不修改單態(tài)接口的情況下方便的做到。
下面是一個(gè)簡單的示例程序:
package Singleton;
public class TestSingleton {
private static TestSingleton testSingleton = null;
protected int count = 0;
public static synchronized TestSingleton getInstance(){
if( testSingleton == null)
testSingleton = new TestSingleton();
return testSingleton;
}
public void addCount(){
count ++;
}
public void showCount(){
System.out.println("count :"+count);
}
}
我們還可以在這個(gè)基礎(chǔ)上做一個(gè)擴(kuò)展，如從上面例子中的TestSingleton類擴(kuò)展出多個(gè)子類，在
getInstance方法中控制要使用的是哪個(gè)子類，具體實(shí)現(xiàn)代碼如下:
-----TestSingleton.java
package Singleton;
public class TestSingleton {
private static TestSingleton testSingleton = null;
protected int count = 0;
public static synchronized TestSingleton getInstance(){
if( testSingleton == null)
testSingleton = new SubTestSingleton ();
return testSingleton;
}
public void addCount(){
count ++;
}
public void showCount(){
System.out.println("TestSingleton count :"+count);
}
}
-----SubTestSingleton.java
public class SubTestSingleton extends TestSingleton{
public void showCount(){
System.out.println("SubTestSingleton count :"+count);
}
}
<以上為個(gè)人見解,歡迎大家評(píng)論!>
最近對(duì)面向?qū)ο蟮脑O(shè)計(jì)的23種經(jīng)典的設(shè)計(jì)模式做了一個(gè)研究,接下來的Blog中我會(huì)按我的理解做個(gè)簡單介紹并提供我寫的示例代碼,歡迎大家的評(píng)論,共同提高.
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