Spring_source_thinking01

在写代码的时候，如果发现传入的参数为空的时候，

需要写一个Assert的类notNull方法抛出IllegalArgumentException

public ClassPathResource(String path, ClassLoader classLoader) {
Assert.notNull(path, "Path must not be null");
String pathToUse = StringUtils.cleanPath(path);
if (pathToUse.startsWith("/")) {
pathToUse = pathToUse.substring(1);
}
this.path = pathToUse;
this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
}

如果在StringUtils.cleanPath(path);的时候直接用if来判断就可以了

public static String cleanPath(String path) {
if (path == null) {
return null;
}
String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);