1. 驗證Validation
1.1 基本用法
// Bean
public class Person {
private String name;
private int age;
//setter & getter, constructor略
}
// Validator
public class PersonValidator implements Validator {
public boolean supports(Class<?> aClass) {
return Person.class.isAssignableFrom(aClass);
}
public void validate(Object o, Errors errors) {
ValidationUtils.rejectIfEmpty(errors, "name", "person.name.null", "Person name cannot be null.");
Person person = (Person) o;
if (person.getAge() < 0)
errors.reject("person.age.negative", "Age cannot be negative.");
}
}
// 驗證
@Test
public void testPersonValidator() {
Person person = new Person("張三", -10);
PersonValidator validator = new PersonValidator();
Assert.assertTrue(validator.supports(Person.class));
Errors errors = new DirectFieldBindingResult(person, "person");
//亦可以使用ValidationUtils.invokeValidator(...)
validator.validate(person, errors);
for (ObjectError objectError : errors.getAllErrors()) {
System.out.println("Error Code is: " + objectError.getCode() + " | " + "Error DefaultMessage is: " + objectError.getDefaultMessage());
}
}
// web容器環境的用法在SpringMVC部分介紹
1.2 在消息格式化中進行驗證
[參考]
java
#properties消息文件 person.age.negative=\u5e74\u9f84\u4e0d\u80fd\u5c0f\u4e8e\u0030+ person.name.null=\u7528\u6237\u540d\u4e0d\u80fd\u4e3a\u7a7a
// 自定義MessageCodesResolver
@Component
public class MyMessageCodesResolver implements MessageCodesResolver {
@Autowired
ApplicationContext context;
public String[] resolveMessageCodes(String errorCode, String objectName) {
return new String[]{context.getMessage(errorCode, null, null)};
}
public String[] resolveMessageCodes(String errorCode, String objectName, String field, Class<?> fieldType) {
return resolveMessageCodes(errorCode, objectName);
}
}
// 驗證
BeanPropertyBindingResult bindingResult = new BeanPropertyBindingResult(person, "person");
bindingResult.setMessageCodesResolver(myMessageCodesResolver);
ValidationUtils.invokeValidator(new PersonValidator(), person, bindingResult);
for (ObjectError objectError : bindingResult.getAllErrors()) {
System.out.println("Error Code is: " + objectError.getCode() + " | " + "Error DefaultMessage is: " + objectError.getDefaultMessage());
}
1.3 BeanValidation規範JSR303, JSR409的支持
- Spring完整支持JSR303 (BeanValidation 1.0)，該規範定義了基於註解方式的JavaBean驗證元數據模型和API，也能夠經過XML進行元數據定義，但註解將覆蓋XML的元數據定義。git
- Spring也支持JSR409 (BeanValidation 1.1)，該規範標準化了Java平臺的約束定義、描述和驗證，其實現例如Hibernate Validatorweb
- JSR303主要是對JavaBean進行驗證，如方法級別（方法參數/返回值）、依賴注入等的驗證是沒有指定的。所以又有了JSR-349規範的產生。正則表達式
[參考]
spring
1.3.1 JSR303
JSR-303原生支持的限制有以下幾種數據庫
| 限制 | 說明 |
| @Null | |
| @NotNull | |
| @AssertFalse | |
| @AssertTrue | |
| @DecimalMax(value) | 不大於指定值的數字 |
| @DecimalMin(value) | 不小於指定值的數字 |
| @Digits(integer,fraction) | 小數，且整數部分的位數不能超過integer，小數部分的位數不能超過fraction |
| @Max(value) | 不大於指定值的數字 |
| @Min(value) | 不小於指定值的數字 |
| @Pattern(value) | 符合指定的正則表達式 |
| @Size(max,min) | 字符長度必須在min到max之間 |
| @Future | 未來的日期 |
| @Past | 過去的日期 |
1.3.2 自定義限制
// 定義限制
@Target({ElementType.FIELD, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy=MoneyValidator.class)
public @interface Money {
String message() default "不是金額形式";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
// 定義限制驗證器
public class MoneyValidator implements ConstraintValidator<Money, Double> {
private String moneyReg = "^\\d+(\\.\\d{1,2})?$";//表示金額的正則表達式
private Pattern moneyPattern = Pattern.compile(moneyReg);
public boolean isValid(Double value, ConstraintValidatorContext arg1) {
if (value == null)
return true;
return moneyPattern.matcher(value.toString()).matches();
}
}
1.3.3 配置Bean Validation Provider
<!-- 配置LocalValidatorFactoryBean，Spring會自動查找並加載類路徑下的provider，例如Hibernate Validator --> <bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/> <!-- 配置後，就能夠經過注入validator的方式使用validator -->
1.3.4 Spring驅動的方法驗證
對方法的參數、返回值進行驗證 [參考]
app
// 沒有方法驗證時的作法
public UserModel get(Integer uuid) {
//前置條件
Assert.notNull(uuid);
Assert.isTrue(uuid > 0, "uuid must lt 0");
//獲取 User Model
UserModel user = getUserModel(uuid); //從數據庫獲取
//後置條件
Assert.notNull(user);
return user;
}
// 有方法驗證時的作法
// a. 使用方法驗證
@Validated // 告訴MethodValidationPostProcessor此Bean須要開啓方法級別驗證支持
public class UserService {
public @NotNull UserModel getUserModel(@NotNull @Min(value = 1) Integer uuid) { //聲明前置條件/後置條件
if(uuid > 100) {//方便後置添加的判斷（此處假設傳入的uuid>100 則返回null）
return null;
}
return getUserModel(uuid); //從數據庫獲取
}
}
// b. 配置方法驗證的後處理器
<bean class="org.springframework.validation.beanvalidation.MethodValidationPostProcessor"/>
// c. 測試用例
@RunWith(value = SpringJUnit4ClassRunner.class)
@ContextConfiguration(value = {"classpath:spring-config-method-validator.xml"})
public class MethodValidatorTest {
@Autowired
UserService userService;
@Test
public void testConditionSuccess() { // 正常流程
userService.getUserModel(1);
}
@Test(expected = org.hibernate.validator.method.MethodConstraintViolationException.class)
public void testPreCondtionFail() { // 錯誤的uuid(即前置條件不知足)
userService.getUserModel(0);
}
@Test(expected = org.hibernate.validator.method.MethodConstraintViolationException.class)
public void testPostCondtionFail() { // 不知足後置條件的返回值
userService.getUserModel(10000);
}
}
1.4 在數據綁定中使用validator
Foo target = new Foo(); DataBinder binder = new DataBinder(target); binder.setValidator(new FooValidator1()); binder.addValidators(new FooValidator2()); binder.replaceValidators(new FooValidator3()); // bind to the target object binder.bind(propertyValues); // validate the target object binder.validate(); // get BindingResult that includes any validation errors BindingResult results = binder.getBindingResult();
2. 操做Bean
2.1 BeanWrapper
- 封裝一個bean的行爲，諸如設置和獲取屬性值等編輯器
- 根據JavaDoc中的說明，BeanWrapper提供了設置和獲取屬性值（單個的或者是批量的），獲取屬性描述信息、查詢只讀或者可寫屬性等功能。不只如此，BeanWrapper還支持嵌套屬性，設置子屬性的值。BeanWrapper無需任何輔助代碼就能夠支持標準JavaBean的PropertyChangeListeners和VetoableChangeListeners。此外，還支持設置索引屬性。一般不直接使用BeanWrapper而是使用DataBinder 和BeanFactoryide
// 被操做的類
class Engine {
private String name;
//setter & getter ...
}
// 被操做的類
class Car {
private String name;
private Engine engine;
//setter & getter ...
}
// 建立並設置Bean
BeanWrapper engine = BeanWrapperImpl(new Engine());
engine.setPropertyValue("name", "N73B68A"); // 也能夠這樣設置 engine.setPropertyValue(new PropertyValue("name", "N73B68A");
// 建立並設置Bean
BeanWrapper car = BeanWrapperImpl(new Car());
car.setPropertyValue("name", "勞斯萊斯幻影");
car.setPropertyValue("engine", engine.getWrappedInstance());
// 獲取嵌套屬性
String engineName = (String) car.getPropertyValue("engine.name");
2.2 PropertyEditor
- Spring大量使用了PropertyEditor以在Object和 String之間進行轉化工具
- PE原本是Java爲IDE可視化設置JavaBean屬性而準備的，Spring對此進行了封裝以簡化使用[參考]
2.2.1 Spring內建屬性編輯器
| 類型 | 內建PropertyEditor (是否已在BeanWrapperImpl註冊) |
| 基礎數據 | ByteArrayProperty (Y)、CustomBoolean (Y)、CustomDate (N)、CustomNumber (Y) |
| 集合 | CustomCollection (?) |
| 資源 | Class (Y)、File (Y)、InputStream (Y)、Locale (Y)、Pattern (?)、Properties (Y)、URL (Y)、StringTrimmer (N) |
2.2.2 自定義屬性編輯器
2.2.2.1 擴展PropertyEditorSupport
// 定義Editor
class EngineEditor extends PropertyEditorSupport {
public void setAsText(String text){
if(text == null)
throw new IllegalArgumentException("設置的字符串格式不正確");
Engine engine = new Engine();
engine.setName(text);
setValue(engine);
}
}
// 註冊Editor // 若是自定義Editor和被處理的類在同一包下面，則無需xml註冊，會被自動識別 <bean class="org.springframework.beans.factory.config.CustomEditorConfigurer"> <property name="customEditors"> <map> <entry key="x.y.z.Engine" value="x.y.z.EngineEditor"/> </map> </property> </bean> // 使用Editor <bean id="car" class="x.y.z.Car" p:name="勞斯萊斯幻影"> <property name="engine" value="N73B68A" /> </bean>
2.2.2.2 實現PropertyEditorRegistrar接口
在不一樣狀況下（如編寫一個相應的註冊器而後在多種狀況下重用它）須要使用相同的屬性編輯器時該接口特別有用
// 如今Java代碼裏面註冊
public final class CustomPropertyEditorRegistrar implements PropertyEditorRegistrar {
public void registerCustomEditors(PropertyEditorRegistry registry) {
registry.registerCustomEditor(Engine.class, new EngineEditor());
}
}
<!-- 再到XML註冊 --> <bean id="customPropertyEditorRegistrar" class="com.foo.editors.spring.CustomPropertyEditorRegistrar"/> <bean class="org.springframework.beans.factory.config.CustomEditorConfigurer"> <property name="propertyEditorRegistrars"> <list> <ref bean="customPropertyEditorRegistrar"/> </list> </property> </bean>
3. 類型轉換
3.1 概述
- Spring容器使用轉換器進行屬性注入；SpEL和DataBinder使用轉換器綁定值
- 不一樣於Property的Object和String之間的轉換，類型轉換能夠有更多的格式互轉
- 轉換器Converter可實現如下接口：
非泛型的強類型轉換用Converter接口
一個源類型轉成指定基類的子類型用ConverterFactory接口
多個源類型轉成多個目標類型用GenericConverter接口，優先用前面兩個
- ConversionService接口實現做爲無狀態的工具在運行時提供轉換服務，可供多個線程共享，可在其中設置各類轉換器.
3.2 Converter接口
將一個源類型轉換成一個目標類型
public interface Converter<S, T> {
T convert(S source);
}
final class StringToCarConverter implements Converter<String, Car> {
public Car convert(String source) {
return new Car(source);
}
}
3.3 ConverterFactory接口
一個源類型轉成指定基類的子類型
public interface ConverterFactory<S, R> {
<T extends R> Converter<S, T> getConverter(Class<T> targetType);
}
// given Car & Truck extends Auto
final class StringToAutoConverterFactory implements ConverterFactory<String, Auto> {
public <T extends Auto> Converter<String, T> getConverter(Class<T> targetType) {
if(targetType.getType() == Car.class)
return new StringToCarConverter();
else if(targetType.getType() == Truck.class)
return new StringToTruckConverter();
else
throw new ConversionFailedException(String.getType(), targetType, null, new Throwable("不支持的轉換類型"));
}
private final class StringToCarConverter implements Converter<String, Car> {
public Car convert(String source) {
return new Car(source);
}
}
// StringToTruckConverter ...
}
3.4 GenericConverter接口
- 多個源類型轉成多個目標類型
- ConditionalGenericConverter接口繼承該接口，增長了boolean matches(...)方法
public interface GenericConverter {
Set<ConvertiblePair> getConvertibleTypes();
Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType);
public static final class ConvertiblePair {
public ConvertiblePair(Class<?> sourceType, Class<?> targetType) {
Assert.notNull(sourceType, "Source type must not be null");
Assert.notNull(targetType, "Target type must not be null");
this.sourceType = sourceType;
this.targetType = targetType;
}
private final Class<?> sourceType;
private final Class<?> targetType;
// getter & setter
}
}
final class GiftGenericConverter implements GenericConverter {
public Set<ConvertiblePair> getConvertibleTypes() {
Set<ConvertiblePair> pairs = new HashSet<ConvertiblePair>();
paris.add(new ConvertiblePair(String.class, Flower.class));
paris.add(new ConvertiblePair(Integer.class, Toy.class));
return pairs;
}
Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
if (source == null || sourceType == TypeDescriptor.NULL || targetType == TypeDescriptor.NULL) {
throw new ConversionFailedException(sourceType, targetType, null,
new IllegalArgumentException("A null value cannot be assigned to a primitive type"));
}
if(targetType.getType() == String.class)
return new Flower(source);
else if(targetType.getType() == Integer.class)
return new Toy(source);
}
}
3.5 Conversion Service
- 無狀態的工具在運行時提供轉換服務，可供多個線程共享，可在其中設置各類轉換器
- 內置GenericConversionService實現ConvensionService接口
- 也能夠配置ConversionServiceFactoryBean提供轉換服務
3.5.1 GenericConversionService
<bean id="conversionService" class="org.springframework.core.convert.support.GenericConversionService"/>
// 注入轉換Bean就可使用轉換服務了
@Autowired
ConversionService conversionService;
public void doSth() {
conversionService.convert(source, targetType);
List<Integer> input = ....
conversionService.convert(input,
TypeDescriptor.forObject(input), // List<Integer> type descriptor
TypeDescriptor.collection(List.class, TypeDescriptor.valueOf(String.class)));
}
// 也能夠建立轉換器實例，一般不須要
3.5.2 ConversionServiceFactoryBean
<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean"> <property name="converters"> <set> <bean class="x.y.z.StringToCarConverter"/> <bean class="x.y.z.StringToAutoConverterFactory"/> <bean class="x.y.z.GiftGenericConverter"/> </set> </property> </bean>
// 使用方法同GenericConversionService
4. 格式化
4.1 概述
Spring格式化Formatter與Converter相似，但能夠指定Locale，根據不一樣的Locale進行不一樣的雙向格式化 (print/parse)
4.2 Formatter接口
public interface Formatter<T> extends Printer<T>, Parser<T> {
}
public final class MyDateFormatter implements Formatter<Date> {
public String print(Date object, Locale locale) {
return new SimpleDateFormat("yyyy-MM-dd", locale).format(object);
}
public Date parse(String text, Locale locale) throws ParseException {
return new SimpleDateFormat("yyyy-MM-dd", locale).parse(text);
}
}
4.3 基於註解的格式化
public interface AnnotationFormatterFactory<A extends Annotation> {
Set<Class<?>> getFieldTypes();
Printer<?> getPrinter(A annotation, Class<?> fieldType);
Parser<?> getParser(A annotation, Class<?> fieldType);
}
// a. 建立註解
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
public @interface PhoneNumber {
}
// b. 要格式化的模型
public class PhoneNumberModel {
private int areaCode, userNumber;
// getter & setter, constructor ...
}
// c. 實現工廠接口
public class PhoneNumberFormatAnnotationFormatterFactory implements AnnotationFormatterFactory<PhoneNumber> {
public Set<Class<?>> getFieldTypes() {
return fieldTypes;
}
public Parser<?> getParser(PhoneNumber annotation, Class<?> fieldType) {
return formatter;
}
public Printer<?> getPrinter(PhoneNumber annotation, Class<?> fieldType) {
return formatter;
}
private final Set<Class<?>> fieldTypes;
private final PhoneNumberFormatter formatter;
public PhoneNumberFormatAnnotationFormatterFactory() {
Set<Class<?>> set = new HashSet<Class<?>>();
set.add(PhoneNumberModel.class);
this.fieldTypes = set;
this.formatter = new PhoneNumberFormatter(); // 以前定義的Formatter實現
}
}
// d. 在須要格式化的字段前面加註解
public class contact {
@PhoneNumber
private PhoneNumberModel phoneNumber;
// other fields ...
}
// e. 測試使用。這個用例有些牽強，更可能是註冊後，在屬性注入、SpEL、數據綁定時，由容器調用自動完成格式化
@Test
public void test() throws SecurityException, NoSuchFieldException {
DefaultFormattingConversionService conversionService = new DefaultFormattingConversionService(); // 建立格式化服務
conversionService.addFormatterForFieldAnnotation(new PhoneNumberFormatAnnotationFormatterFactory()); // 添加自定義的註解格式化工廠
TypeDescriptor phoneNumberDescriptor = new TypeDescriptor(FormatterModel.class.getDeclaredField("phoneNumber"));
TypeDescriptor stringDescriptor = TypeDescriptor.valueOf(String.class);
PhoneNumberModel value = (PhoneNumberModel) conversionService.convert("010-12345678", stringDescriptor, phoneNumberDescriptor); // 解析字符串"010-12345678"--> PhoneNumberModel
ContactModel contact = new ContactModel();
contact.setPhoneNumber(value);
Assert.assertEquals("010-12345678", conversionService.convert(contact.getPhoneNumber(), phoneNumberDescriptor, stringDescriptor)); // 格式化PhoneNumberModel-->"010-12345678"
}
4.4 註冊Formatter
- 實現FormatterRegistry接口，或使用內置實現FormattingConversionService，一般使用FormattingConversionServiceFactoryBean進行配置
- 實現FormatterRegistrar接口
<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean"> <property name="formatters"> <list> <bean class="x.y.z.PhoneNumberFormatAnnotationFormatterFactory"/> </list> </property> <property name="converters"> <set> <bean class="org.example.MyConverter"/> </set> </property> <property name="formatterRegistrars"> <set> <bean class="org.example.MyFormatterRegistrar"/> </set> </property> </bean>
4.5 註冊全局日期和時間格式
Spring默認使用DateFormat.SHORT進行日期和時間格式化，在DefaultFormattingConversionService未被註冊的狀況下，能夠自定義全局日期和時間格式
// a. 以JavaConfig的方式註冊全局日期格式yyyyMMdd
@Bean
public FormattingConversionService conversionService() {
// 使用但不註冊DefaultFormattingConversionService
DefaultFormattingConversionService conversionService = new DefaultFormattingConversionService(false);
// 確保@NumberFormat被支持
conversionService.addFormatterForFieldAnnotation(new NumberFormatAnnotationFormatterFactory());
// 註冊全局格式
DateFormatterRegistrar registrar = new DateFormatterRegistrar();
registrar.setFormatter(new DateFormatter("yyyyMMdd"));
registrar.registerFormatters(conversionService);
return conversionService;
}
<!-- b. 以xml的方式註冊全局日期格式yyyyMMdd，且用到了Joda-Time第三方庫 <bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean"> <property name="registerDefaultFormatters" value="false" /> <property name="formatters"> <set> <bean class="org.springframework.format.number.NumberFormatAnnotationFormatterFactory" /> </set> </property> <property name="formatterRegistrars"> <set> <bean class="org.springframework.format.datetime.joda.JodaTimeFormatterRegistrar"> <property name="dateFormatter"> <bean class="org.springframework.format.datetime.joda.DateTimeFormatterFactoryBean"> <property name="pattern" value="yyyyMMdd"/> </bean> </property> </bean> </set> </property> </bean>