JAVA - 数组元素格式化输出

snippet.java

@visibleForTesting static String format (String template, @Nullable Object... args)
{
	template = String.valueOf(template);

	StringBuffer builder = new StringBuffer(template.length() + 16 * args.length);
	int templateStart = 0;
	int i = 0;
	while(i < args.length)
	{
		int placeholderStart = template.indexOf("%s", templateStart);
		if(placeholderStart == -1)
			break;
		builder.append(template.substring(templateStart, placeholderStart));
		builder.append(args[i++]);
		templateStart = placeholderStart + 2;
	}
	builder.append(template.substring(templateStart));

	if(i < args.length)
	{
		builder.append(" [");
		builder.append(args[i ++]);
		while(i < args.length)
		{
			builder.append(", ");
			builder.append(args[i++]);
		}
		builder.append("]");
	}
	return builder.toString();
}

public static <T> T checkNotNull(T reference, @Nullable String errorMessageTemplate, 
									@Nullable Object... errorMessage)
{
	if(reference == null)
		throw new NullPointerException(format(errorMessageTemplate, errorMessage));
	return reference;
}