BeanValidator一般使用方法 2018-02-06

获取Validator实例：

ValidatorFactory factory = Validation.buildDefaultValidatorFactory();

validator = factory.getValidator();

Validator实例是线程安全的，因此可以在多线程情况下重复使用同一个实例多次。

Validator包含了3个验证方法：

1.验证bean对象实例

Car car = new Car( null, true );

Set<ConstraintViolation<Car>> constraintViolations = validator.validate(car);

assertEquals( 1, constraintViolations.size() );

assertEquals( "must not be null", constraintViolations.iterator().next() .getMessage() );

2.验证实例对象的某个属性

Car car = new Car( null, true );

Set<ConstraintViolation <Car>>  constraintViolations = validator.validate(car , "manufacturer" );

assertEquals( 1, constraintViolations.size() );

assertEquals( "must not be null", constraintViolations.iterator().next() .getMessage() );

3.验证某个值是否对某个属性有效（可用于在赋值前检查）

Set<ConstraintViolation<Car>> constraintViolations = validator.validateValue( Car.class, "manufacturer", null );

assertEquals( 1, constraintViolations.size() );

assertEquals( "must not be null", constraintViolations.iterator().next() .getMessage() );