概述
====
模板设计模式的两种方式:
1.基于继承的实现
2.基于组合的实现
一、基于继承的实现
1.首先,创建一个模板类MyJdbcTemplateByIn,在模板类的execute方法中定义调用过程
public abstract class MyJdbcTemplateByIn {
private void beginConnection()
{
System.out.println("begin connetction");
}
private void closeConnection()
{
System.out.println("close connetction");
}
public abstract void run();
public void execute()
{
beginConnection();
run();
closeConnection();
}
}
2.创建类RoleDao和MessageDao继承于模板类MyJdbcTemplateByIn,并分别重写run方法
public class RoleDao extends MyJdbcTemplateByIn {
@Override
public void run() {
System.out.println("role add");
}
}
public class MessageDao extends MyJdbcTemplateByIn {
@Override
public void run() {
System.out.println("message add");
}
}
3.测试
public class TestTemplate {
//基于继承的方式
@test
public void test1() throws Exception {
MyJdbcTemplateByIn myJdbcTemplateByIn = new RoleDao();
myJdbcTemplateByIn.execute();
System.out.println("=============");
MyJdbcTemplateByIn myJdbcTemplateByIn2 = new MessageDao();
myJdbcTemplateByIn2.execute();
}
运行结果为
begin connetction
role add
close connetction
=============
begin connetction
message add
close connetction
二、基于组合的实现
1.首先创建模板类
public class MyJdbcTemplate {
private void beginConnection()
{
System.out.println("begin connetction");
}
private void closeConnection()
{
System.out.println("close connetction");
}
/**
* 调用方法:传入一个钩子函数的接口
*/
public void execute(MyCallback callback)
{
beginConnection();
callback.doInTemplate();
closeConnection();
}
/**
* 将所有要实现的方法都创建在模板中
*/
public void add(final int id)
{
execute(new MyCallback() {
@Override
public void doInTemplate() {
System.out.println("add"+id);
}
});
}
public void delete(final int id)
{
execute(new MyCallback() {
@Override
public void doInTemplate() {
System.out.println("delete"+id);
}
});
}
}
public interface MyCallback {
public void doInTemplate();
}
public class RoleDao extends MyJdbcTemplateByIn {
private MyJdbcTemplate mt = new MyJdbcTemplate();
public void add(int id)
{
mt.add(id);
}
public void delete(int id)
{
mt.delete(id);
}
@Override
public void run() {
System.out.println("role add");
}
@Override
public boolean isLog() {
return false;
}
}
public class TestTemplate {
//基于组合的方式
@Test
public void test2() throws Exception {
RoleDao roleDao = new RoleDao();
roleDao.add(1);
System.out.println("=============");
roleDao.delete(2);
}
}
运行结果:
begin connetction
add1
close connetction
=============
begin connetction
delete2
close connetction