spring 枚举、策略模式、InitializingBean初使化组合使用示例

实现一个简单的文本处理系统。
在这个系统中，我们将定义不同类型的文本处理策略，比如大小写转换、添加前缀后缀等，并使用工厂模式来管理这些策略。

1 定义一个枚举来标识不同的文本处理类型

public enum TextProcessTypeEnum {UPPER_CASE,LOWER_CASE,PREFIX_SUFFIX// 可以继续添加更多的文本处理类型
}

2 定义一个策略接口，所有的文本处理策略都将实现这个接口

public interface TextProcessHandler {public String process(String txt);public TextProcessTypeEnum getHandlerType();
}

3 实现几个具体的策略类

import org.springframework.stereotype.Service;@Service
public class UpperCaseHandler implements TextProcessHandler {@Overridepublic String process(String txt) {return txt.toUpperCase();}@Overridepublic TextProcessTypeEnum getHandlerType() {return TextProcessTypeEnum.UPPER_CASE;}
}@Service
public class LowerCaseHandler implements TextProcessHandler {@Overridepublic String process(String txt) {return txt.toLowerCase();}@Overridepublic TextProcessTypeEnum getHandlerType() {return TextProcessTypeEnum.LOWER_CASE;}
}@Service
@NoArgsConstructor
public class PrefixSuffixHandler implements TextProcessHandler {@Value("start--")private String prefix;@Value("--end")private String suffix;public PrefixSuffixHandler(String prefix, String suffix) {this.prefix = prefix;this.suffix = suffix;}@Overridepublic String process(String txt) {return prefix +txt+ suffix;}@Overridepublic TextProcessTypeEnum getHandlerType() {return TextProcessTypeEnum.PREFIX_SUFFIX;}
}

4 创建一个工厂类来管理这些策略

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.HashMap;
import java.util.List;
import java.util.Map;@Component
public class TextProcessHandlerFactory implements InitializingBean {@Autowiredprivate List<TextProcessHandler> textProcessHandlerList;private final Map<TextProcessTypeEnum, TextProcessHandler> handlerMap =new HashMap<>();@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("textProcessHandlerList = " + textProcessHandlerList);for (TextProcessHandler handler : textProcessHandlerList) {handlerMap.put(handler.getHandlerType(), handler);}System.out.println("handlerMap = " + handlerMap);}public TextProcessHandler getHandler(TextProcessTypeEnum typeEnum){return handlerMap.get(typeEnum);}
}

5 使用这个工厂来获取相应的处理器，并处理文本

@SpringBootTest
class DemoMvnTest1ApplicationTests {@Autowiredprivate TextProcessHandlerFactory factory;@Testvoid contextLoads() {TextProcessHandler handler = factory.getHandler(TextProcessTypeEnum.UPPER_CASE);System.out.println(handler.process("hello world"));System.out.println();handler = factory.getHandler(TextProcessTypeEnum.LOWER_CASE);System.out.println(handler.process("HELLO WORLD"));System.out.println();handler = factory.getHandler(TextProcessTypeEnum.PREFIX_SUFFIX);System.out.println(handler.process("hello world"));}}