定义了算法家族，分别封装起来，让它们之间可以相互替换，此模式让算法的变化，不会影响到使用算法的客户。
类图
实现
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| public interface Strategy {
public void behavior();
}
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| public class ConcreteStrategyA implements Strategy {
@Override
public void behavior() {
System.out.println("执行算法A...");
}
}
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| public class ConcreteStrategyB implements Strategy {
@Override
public void behavior() {
System.out.println("执行算法B...");
}
}
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| public class Context {
private Strategy strategy;
public void setStrategy(Strategy strategy) {
this.strategy = strategy;
}
public void doSomething() {
strategy.behavior();
}
}
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| public class Client {
public static void main(String[] args) {
Context context = new Context();
context.setStrategy(new ConcreteStrategyA());
context.doSomething();
context.setStrategy(new ConcreteStrategyB());
context.doSomething();
}
}
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