【Springboot】排除多余依赖与Bean实例

一、背景： 引入公共包之后，需要排除部分不需要的包和bean，给当前服务最大程度减重

二、实现：

1.在pom.xml排除依赖

 2.在启动类上添加扫描排除项

@ComponentScan(basePackages = {"com.xxx"},
      excludeFilters = {
            @ComponentScan.Filter(
                  type = FilterType.CUSTOM, classes = {ScanExcludeFilter.class}
            )
      })
public class Application {

   public static void main(String[] args) throws Exception {
      SpringApplication.run(Application.class, args);
   }

}

其中，FilterType有以下几种：

public enum FilterType {
    ANNOTATION, //按照注解过滤
    ASSIGNABLE_TYPE, //按照类型过滤
    ASPECTJ,//按照ASPECTJ表达式过滤
    REGEX,//按照正则表达式过滤
    CUSTOM;//按照自定义的过滤规则过滤
    private FilterType() {
    }
}

3.实现TypeFilter

public class ScanExcludeFilter implements TypeFilter {

	// 需要的Bean包含的关键字
	private static final List<String> containsKeyWords = Arrays.asList(
			"core.config",
			"common.dao"
	);
	// 不能的Bean包含的关键字
	private static final List<String> excludeKeyWords = Arrays.asList(
			"XxxConfig"
	);

	@Override
	public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
		ClassMetadata classMetadata = metadataReader.getClassMetadata();
		String className = classMetadata.getClassName();
		if (!className.contains("ema")) {
			return false;
		}
		// 先走排除
		if (isExculdeBean(className)) {
			return true;
		}
		// 再看是否真的满足
		return !needContains(className);
	}

	// 匹配不需要的bean
	private boolean isExculdeBean(String className) {
		for (String keyword : excludeKeyWords) {
			if (className.contains(keyword)) {
				return true;
			}
		}
		return false;
	}

	// 匹配需要的bean
	private boolean needContains(String className) {
		for (String keyword : containsKeyWords) {
			if (className.contains(keyword)) {
				return true;
			}
		}
		return false;
	}


}