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一、声明bean约束

1. 字段级别约束

不支持静态类型字段
验证引擎直接访问实例变量，不会调用属性的访问器
在验证字节码增强的对象时，应适用属性级别约束，因为字节码增库无法通过反射确定字段访问

package org.hibernate.validator.referenceguide.chapter02.fieldlevel;
public class Car {
    @NotNull
    private String manufacturer;
    @AssertTrue
    private boolean isRegistered;
    public Car(String manufacturer, boolean isRegistered) {
        this.manufacturer = manufacturer;
        this.isRegistered = isRegistered;
    }
    //getters and setters...
}

2. 属性级别约束

必须注释getter而不是setter，这样可以限制没有设置方法的只读属性
该级别将使用属性访问策略来访问验证的值，即验证引擎通过属性访问器来访问数据
不要字段和getter都加校验，这样会导致校验两次

package org.hibernate.validator.referenceguide.chapter02.propertylevel;
public class Car {
    private String manufacturer;
    private boolean isRegistered;
    public Car(String manufacturer, boolean isRegistered) {
        this.manufacturer = manufacturer;
        this.isRegistered = isRegistered;
    }
    @NotNull
    public String getManufacturer() {
        return manufacturer;
    }
    public void setManufacturer(String manufacturer) {
        this.manufacturer = manufacturer;
    }
    @AssertTrue
    public boolean isRegistered() {
        return isRegistered;
    }
    public void setRegistered(boolean isRegistered) {
        this.isRegistered = isRegistered;
    }
}

容器元素约束

3.1 Iterable

在该类型上加约束时，将会校验每个元素

package org.hibernate.validator.referenceguide.chapter02.containerelement.set;
import java.util.HashSet;
import java.util.Set;
public class Car {
    private Set<@ValidPart String> parts = new HashSet<>();
    public void addPart(String part) {
        parts.add( part );
    }
    //...
}

Car car = new Car();
car.addPart( "Wheel" );
car.addPart( null );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation =
        constraintViolations.iterator().next();
assertEquals(
        "'null' is not a valid car part.",
        constraintViolation.getMessage()
);
assertEquals( "parts[].<iterable element>",
        constraintViolation.getPropertyPath().toString() );

3.2 List

也会校验每个元素

package org.hibernate.validator.referenceguide.chapter02.containerelement.list;
public class Car {
    private List<@ValidPart String> parts = new ArrayList<>();
    public void addPart(String part) {
        parts.add( part );
    }
    //...
}

Car car = new Car();
car.addPart( "Wheel" );
car.addPart( null );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation =
        constraintViolations.iterator().next();
assertEquals(
        "'null' is not a valid car part.",
        constraintViolation.getMessage()
);
assertEquals( "parts[1].<list element>",
        constraintViolation.getPropertyPath().toString() );

3.3 Map

package org.hibernate.validator.referenceguide.chapter02.containerelement.map;
import java.util.HashMap;
import java.util.Map;
import javax.validation.constraints.NotNull;
public class Car {
    public enum FuelConsumption {
        CITY,
        HIGHWAY
    }
    private Map<@NotNull FuelConsumption, @MaxAllowedFuelConsumption Integer> fuelConsumption = new HashMap<>();
    public void setFuelConsumption(FuelConsumption consumption, int value) {
        fuelConsumption.put( consumption, value );
    }
    //...
}

Car car = new Car();
car.setFuelConsumption( Car.FuelConsumption.HIGHWAY, 20 );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation =
        constraintViolations.iterator().next();
assertEquals(
        "20 is outside the max fuel consumption.",
        constraintViolation.getMessage()
);
assertEquals(
        "fuelConsumption[HIGHWAY].<map value>",
        constraintViolation.getPropertyPath().toString()
);

Car car = new Car();
car.setFuelConsumption( null, 5 );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation =
        constraintViolations.iterator().next();
assertEquals(
        "must not be null",
        constraintViolation.getMessage()
);
assertEquals(
        "fuelConsumption<K>[].<map key>",
        constraintViolation.getPropertyPath().toString()
);

3.4 Optional

package org.hibernate.validator.referenceguide.chapter02.containerelement.optional;
public class Car {
    private Optional<@MinTowingCapacity(1000) Integer> towingCapacity = Optional.empty();
    public void setTowingCapacity(Integer alias) {
        towingCapacity = Optional.of( alias );
    }
    //...
}

Car car = new Car();
car.setTowingCapacity( 100 );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation = constraintViolations.iterator().next();
assertEquals(
        "Not enough towing capacity.",
        constraintViolation.getMessage()
);
assertEquals(
        "towingCapacity",
        constraintViolation.getPropertyPath().toString()
);

3.5 自定义容器

package org.hibernate.validator.referenceguide.chapter02.containerelement.custom;
public class Car {
    private GearBox<@MinTorque(100) Gear> gearBox;
    public void setGearBox(GearBox<Gear> gearBox) {
        this.gearBox = gearBox;
    }
    //...
}

package org.hibernate.validator.referenceguide.chapter02.containerelement.custom;
public class GearBox<T extends Gear> {
    private final T gear;
    public GearBox(T gear) {
        this.gear = gear;
    }
    public Gear getGear() {
        return this.gear;
    }
}

package org.hibernate.validator.referenceguide.chapter02.containerelement.custom;
public class Gear {
    private final Integer torque;
    public Gear(Integer torque) {
        this.torque = torque;
    }
    public Integer getTorque() {
        return torque;
    }
    public static class AcmeGear extends Gear {
        public AcmeGear() {
            super( 60 );
        }
    }
}

package org.hibernate.validator.referenceguide.chapter02.containerelement.custom;
public class GearBoxValueExtractor implements ValueExtractor<GearBox<@ExtractedValue ?>> {
    @Override
    public void extractValues(GearBox<@ExtractedValue ?> originalValue, ValueExtractor.ValueReceiver receiver) {
        receiver.value( null, originalValue.getGear() );
    }
}

Car car = new Car();
car.setGearBox( new GearBox<>( new Gear.AcmeGear() ) );
Set<ConstraintViolation<Car>> constraintViolations = validator.validate( car );
assertEquals( 1, constraintViolations.size() );
ConstraintViolation<Car> constraintViolation =
        constraintViolations.iterator().next();
assertEquals(
        "Gear is not providing enough torque.",
        constraintViolation.getMessage()
);
assertEquals(
        "gearBox",
        constraintViolation.getPropertyPath().toString()
);

3.6 嵌套容器元素

package org.hibernate.validator.referenceguide.chapter02.containerelement.nested;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.validation.constraints.NotNull;
public class Car {
    private Map<@NotNull Part, List<@NotNull Manufacturer>> partManufacturers =
            new HashMap<>();
    //...
}

4. 类级别约束

在这种情况下，验证的对象不是单个属性而是完整的对象
适合依赖于对象的多个属性之间的相关性很高的场景

package org.hibernate.validator.referenceguide.chapter02.classlevel;
@ValidPassengerCount
public class Car {
    private int seatCount;
    private List<Person> passengers;
    //...
}

5. 约束继承

在一个类实现接口或扩展另一个类时，在超类上声明的所有约束注释都以与该类本身上指定的约束相同的方式约束

package org.hibernate.validator.referenceguide.chapter02.inheritance;
public class Car {
    private String manufacturer;
    @NotNull
    public String getManufacturer() {
        return manufacturer;
    }
    //...
}

package org.hibernate.validator.referenceguide.chapter02.inheritance;
public class RentalCar extends Car {
    private String rentalStation;
    @NotNull
    public String getRentalStation() {
        return rentalStation;
    }
    //...
}

RentalCar 不仅会校验getRentalStation，而且会校验父类的getManufacturer
若继承换成接口，也是会校验超类的

6. 对象图

不仅支持单个对象校验，还支持级联验证

对象的级联校验

package org.hibernate.validator.referenceguide.chapter02.objectgraph;
public class Car {
    @NotNull
    @Valid
    private Person driver;
    //...
}

package org.hibernate.validator.referenceguide.chapter02.objectgraph;
public class Person {
    @NotNull
    private String name;
    //...
}

在校验Car的时候，会校验Person，因此若Car引用的Person的name为空，则会校验失败

容器的级联校验

package org.hibernate.validator.referenceguide.chapter02.objectgraph.containerelement;
public class Car {
    private List<@NotNull @Valid Person> passengers = new ArrayList<Person>();
    private Map<@Valid Part, List<@Valid Manufacturer>> partManufacturers = new HashMap<>();
    //...
}

package org.hibernate.validator.referenceguide.chapter02.objectgraph.containerelement;
public class Part {
    @NotNull
    private String name;
    //...
}

package org.hibernate.validator.referenceguide.chapter02.objectgraph.containerelement;
public class Manufacturer {
    @NotNull
    private String name;
    //...
}

校验Person的名字是否存在为null的
校验Part的名字是否存在为null的
校验所有的Manufacturer是否存在名字为null的

二、验证Bean约束

1. 获取验证器

2. 验证的三种方式

先来个车

class Car {
    @NotNull
    @Size(min = 5,max = 20)
    private String manufacturer;
    @AssertTrue
    private boolean isRegistered;
    public Car(String manufacturer, boolean isRegistered) {
        this.manufacturer = manufacturer;
        this.isRegistered = isRegistered;
    }
}

bean全部验证

验证单个属性

对属性的值进行验证

3. 约束违规

内插的错误消息

09:35:00.446 [main] INFO com.bm.validate.TestValidatorBean - 内插的错误消息：只能为true

非插补的错误消息

09:35:00.446 [main] INFO com.bm.validate.TestValidatorBean - 非插补的错误消息：{javax.validation.constraints.AssertTrue.message}

正在验证的根Bean

09:35:00.446 [main] INFO com.bm.validate.TestValidatorBean - 正在验证的根Bean：com.bm.validate.Car@7c83dc97

如果是bean约束，则将约束应用到bean实例；如果是属性约束，则是托管该约束的属性的bean实例

09:35:00.446 [main] INFO com.bm.validate.TestValidatorBean - 如果是bean约束，则将约束应用到bean实例；如果是属性约束，则是托管该约束的属性的bean实例：com.bm.validate.Car@7c83dc97

bean验证器值的属性路径

09:35:00.447 [main] INFO com.bm.validate.TestValidatorBean - 根bean验证器值的属性路径：isRegistered

**报告约束失败的原数据

09:35:00.447 [main] INFO com.bm.validate.TestValidatorBean - 报告约束失败的原数据：false

告约束失败的元数据

09:35:00.447 [main] INFO com.bm.validate.TestValidatorBean - 报告约束失败的元数据：ConstraintDescriptorImpl{annotation=j.v.c.AssertTrue, payloads=[], hasComposingConstraints=true, isReportAsSingleInvalidConstraint=false, elementType=FIELD, definedOn=DEFINED_LOCALLY, groups=[interface javax.validation.groups.Default], attributes={groups=[Ljava.lang.Class;@60015ef5, message={javax.validation.constraints.AssertTrue.message}, payload=[Ljava.lang.Class;@2f54a33d}, constraintType=GENERIC, valueUnwrapping=DEFAULT}

三、内置约束

@AssertFalse

检查带注释元素的属性为false

Boolean, boolean

@AssertTrue

检查带注释元素的属性为True

Boolean,boolean

@DecimalMax(value=, inclusive=)

inclusive为false，检查带注释的值是否小于指定的最大值。否则，该值是否小于等于指定的最大值
BigDecimal,BigInteger,CharSequence,byte,short,int,long，原始数据包装类,Number,javax.money.MonetaryAmount任意子类

@DecimalMin(value=, inclusive=)

inclusive为false，检查带注释的值是否大于指定的最小值。否则，该值是否大于等于指定的最小值
BigDecimal,BigInteger,CharSequence,byte,short,int,long，原始数据包装类,Number,javax.money.MonetaryAmount任意子类

@Digits(integer=, fraction=)

integer 指定整数位数限制，fraction指定小数位数限制
BigDecimal,BigInteger,CharSequence,byte,short,int,long，原始数据包装类,Number,javax.money.MonetaryAmount任意子类

@Email

是否为有效的电子邮箱地址
regexp和flags参数指定正则规则，必须匹配的其它表达式
CharSequence

@Future

检查是否是将来的日期 -

java.util.Date，java.util.Calendar，java.time.Instant，java.time.LocalDate，java.time.LocalDateTime，java.time.LocalTime，java.time.MonthDay，java.time.OffsetDateTime，java.time.OffsetTime，java.time.Year，java.time.YearMonth，java.time.ZonedDateTime，java.time.chrono.HijrahDate，java.time.chrono.JapaneseDate，java.time.chrono.MinguoDate，java.time.chrono.ThaiBuddhistDate; 如果类路径上有Joda Time日期/时间API ，则由HV额外支持：ReadablePartial和的任何实现ReadableInstant

@FutureOnPresent

检查日期是先在还是将来 -

@Max(value=)

是否小于或等于该值
BigDecimal，BigInteger，byte，short，int，long和原始类型的相应的包装; HV额外支持：的任何子类型CharSequence（评估字符序列表示的数值），Number和的任何子类型javax.money.MonetaryAmount

@Min(value=)

是否大于或等于该值
BigDecimal，BigInteger，byte，short，int，long和原始类型的相应的包装; HV额外支持：的任何子类型CharSequence（评估字符序列表示的数值），Number和的任何子类型javax.money.MonetaryAmount

@NotBlank

指定字符不为null并且长度大于0
CharSequence

@NotEmpty

指定字符不为null或为空（去除尾随空格）
CharSequence，Collection，Map和数组

@NotNull

检查注释的值不为null
所有类型均支持

@Negative

检查元素是否严格为负，零被视为无效
BigDecimal，BigInteger，byte，short，int，long和原始类型的相应的包装; HV额外支持：的任何子类型CharSequence（评估字符序列表示的数值），Number和的任何子类型javax.money.MonetaryAmount

@NegativeOrZero

检查元素是负数或0
BigDecimal，BigInteger，byte，short，int，long和原始类型的相应的包装; HV额外支持：的任何子类型CharSequence（评估字符序列表示的数值），Number和的任何子类型javax.money.MonetaryAmount

@Null

检查注释的值是null
所有类型均支持

@Past

检查带注释的日期是否是过去的日期 -

java.util.Date，java.util.Calendar，java.time.Instant，java.time.LocalDate，java.time.LocalDateTime，java.time.LocalTime，java.time.MonthDay，java.time.OffsetDateTime，java.time.OffsetTime，java.time.Year，java.time.YearMonth，java.time.ZonedDateTime，java.time.chrono.HijrahDate，java.time.chrono.JapaneseDate，java.time.chrono.MinguoDate，java.time.chrono.ThaiBuddhistDate; 如果类路径上有Joda Time日期/时间API ，则由HV附加支持：ReadablePartial和的任何实现ReadableInstant

@PastOrPresent

检查带注释的日期是过去还是现在 -