参数的输入和验证问题是开发时经常遇到的,一般的验证方法如下:
public bool Register(string name, int age)
{
if (string.IsNullOrEmpty(name))
{
throw new ArgumentException("name should not be empty", "name");
}
if (age < || age > )
{
throw new ArgumentException("the age must between 10 and 70","age");
}
//...
}
这样做当需求变动的时候,要改动的代码相应的也比较多,这样比较麻烦,最近接触到了Java和C#下2种方便的参数验证方法,简单的介绍下。
Java参数验证:
采用google的guava下的一个辅助类:
import com.google.common.base.Preconditions;
示例代码:
public static void checkPersonInfo(int age, String name){
Preconditions.checkNotNull(name, "name为null");
Preconditions.checkArgument(name.length() > 0, "name的长度要大于0");
Preconditions.checkArgument(age > 0, "age必须大于0");
System.out.println("a person age: " + age + ", name: " + name);
} public static void getPostCode(String code){
Preconditions.checkArgument(checkPostCode(code),"邮政编码不符合要求");
System.out.println(code);
} public static void main(String[] args) {
try {
checkPersonInfo(10,"fdsfsd");
checkPersonInfo(10,null);
checkPersonInfo(-10,"fdsfsd");
getPostCode("012234"); } catch (Exception e) {
e.printStackTrace();
}
}
当参数不满足要求的时候,抛出异常信息,异常中携带的信息为后面自定义的字符串,这样写就方便多了。
C#参数验证:
采用FluentValidation这个类库,参考地址在下面。
使用方法:
一个简单的Person类:
public class Person
{
public string Name { set; get; } public int Age { set; get; } public Person(string name, int age)
{
Name = name;
Age = age;
}
}
Person的验证类:
public class PersonValidator : AbstractValidator<Person>
{
public PersonValidator()
{
RuleFor(x => x.Name).NotEmpty().WithMessage("姓名不能为空");
RuleFor(x => x.Name).Length(,).WithMessage("姓名字符不能超过50");
RuleFor(x => x.Age).GreaterThan().WithMessage("年龄必须要大于0");
} private bool ValidName(string name)
{
// custom name validating logic goes here
return true;
}
}
使用:
class Program
{
static void Main(string[] args)
{
Person customer = new Person(null,-);
PersonValidator validator = new PersonValidator();
ValidationResult results = validator.Validate(customer); bool validationSucceeded = results.IsValid;
IList<ValidationFailure> failures = results.Errors;
foreach (var failure in failures)
{
Console.WriteLine(failure.ErrorMessage);
} Console.ReadKey();
}
}
FluentValidation的使用文档:http://fluentvalidation.codeplex.com/documentation
参考资料:
http://fluentvalidation.codeplex.com/
https://github.com/JeremySkinner/FluentValidation