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java接口的妙用

摘要: java接口的妙用

说明
一气之作,文字功夫太差请大家谅解,希望能对研究COM的朋友带点帮助
接口功能介绍
1、‘纯’抽象类的实现(参见JAVA编程思想P/153)
// Interface1.java 接口只负责描述自己的样子“对于实现我的所有的类,看起来都应该象我这个样子。我所有的方法,实现类都必须有!”
public interface Interface1 {
public void setS(String str);
public String getS();
public void ShowMessage(String MSG); }
=====================================================================
// ClassItf.java “接口只是一个非常‘纯‘的抽象的东西,你的实现代码都在我这里!”
public class ClassItf implements Interface1{
public String S = "";
public ClassItf() { }
public void ShowMessage(String MSG) {
System.out.print(this.getClass().getName()+"====="+MSG+"====by Interface1n/"); }
public void setS(String str) {
S = str; }
public String getS() {
return S; } }
2、多重继承的实现(参见JAVA编程思想P/155)
//Interfase2.java 接口的样子
public interface Interface2 {
public void ShowMessage2(String MSG); }
// ClassItf.java 加入多重继承后的ClassItf 灰底为加入更改、插入行
public class ClassItf implements Interface1,Interface2{
public String S = "";
public ClassItf() { }
public void ShowMessage(String MSG) {
System.out.print(this.getClass().getName()+"====="+MSG+"====by Interface1n/"); }
public void setS(String str) {
S = str; }
public String getS() {
return S; }
public void ShowMessage2(String MSG) {
System.out.print(this.getClass().getName()+"====="+MSG+"====by Interface2n/"); } }
呵呵!我的多重继承功能在JAVA中有着大量的应用如:
public class JFrame extends Frame implements WindowConstants, Accessible, RootPaneContainer
3、外观与实现分离
// ClassItf.java “接口只是一个非常‘纯‘的抽象的东西,你的实现代码都在我这里!”
public class ClassItf implements Interface1,Interface2{

public String S = "";
public ClassItf() { }
public void ShowMessage(String MSG)// 实现了接口‘Interface1’ShowMessage {
System.out.print(this.getClass().getName()+"====="+MSG+"====by Interface1n/");
}
public void setS(String str) //实现了接口‘Interface1’setS
{
S = str; }
public String getS()//实现了接口‘Interface1’getS
{
return S; }
public void ShowMessage2(String MSG)// 实现了接口‘Interface2’ ShowMessage2 {
System.out.print(this.getClass().getName()+"====="+MSG+"====by Interface2n/"); } }
4、提供调用的影子
public void ShowMessage(Interface1 req) {
req.ShowMessage("111"); }
public void ShowMessage2(Interface2 req) {
req.ShowMessage2("111"); }
void jButton1_actionPerformed(ActionEvent e) {
private ClassItf C1 = new ClassItf();
ShowMessage(C1);
ShowMessage2(C1); }
同样呀,我的应用也非常的广呀!
比如在Servlet的
public void doPost(HttpServletRequest request,HttpServletResponse response)
public void doGet(HttpServletRequest request,HttpServletResponse response)
HttpServletRequest ,HttpServletResponse我的应用!
其它如:
事件Listen呀:
public void addActionListener(ActionListener l)
Observer模式呀!
5、通过接口实现引用传递
public void SetS1(Interface1 req) {
req.setS("New Value with C1"); }
public void SetS2(ClassNoitf req) {
req.setS("New Value with C2"); }
void jButton3_actionPerformed(ActionEvent e) {
ClassItf C1 = new ClassItf();
ClassNoitf C2 = new ClassNoitf();
//Set C1
SetS1(C1);
//Set C2;
SetS2(C2);
//Get Value
System.out.print(C1.getS());
System.out.print(C2.getS()); }
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