特殊校驗不能加到web層。 Validator和DataBinder組成了validation包， 主要用于但不限于MVC框架。 3.3 錯誤信息的處理代碼 3.4 Bean操作和 BeanWrapper 3.4.1 得到基本的和嵌套的屬性 Expression Explanation name Indicates the property?name?corresponding to the methods?getName()?or?isName()?and?setName(..) account.name Indicates the nested property?name?of the property?account?corresponding e.g. to the methods?getAccount().setName()?or?getAccount().getName() account[2] Indicates the?third?element of the indexed property?account. Indexed properties can be of type?array,?listor other?naturally ordered?collection account[COMPANYNAME] Indicates the value of the map entry indexed by the key?COMPANYNAME?of the Map property?account 實例： 1. Employee 類： name,salary 2. Company類 name,managingDirector ; managingDirector是一個Employee對象 /** * @Title: Employee.java * @Package com.oscar999.valid * @Description: TODO * @author oscar999 * @date Sep 3, 2018 4:25:22 PM * @version V1.0 */ package com.oscar999.valid; /** * @ClassName: Employee * @Description: TODO * @author oscar999 */ public class Employee { private String name; private float salary; public String getName() { return name; } public void setName(String name) { this.name = name; } public float getSalary() { return salary; } public void setSalary(float salary) { this.salary = salary; } } /** * @Title: Company.java * @Package com.oscar999.valid * @Description: TODO * @author oscar999 * @date Sep 3, 2018 4:24:29 PM * @version V1.0 */ package com.oscar999.valid; /** * @ClassName: Company * @Description: TODO * @author oscar999 */ public class Company { private String name; private Employee managingDirector; public String getName() { return name; } public void setName(String name) { this.name = name; } public Employee getManagingDirector() { return managingDirector; } public void setManagingDirector(Employee managingDirector) { this.managingDirector = managingDirector; } } /** * @Title: BeanWrapperTest.java * @Package com.oscar999.valid * @Description: TODO * @author oscar999 * @date Sep 3, 2018 4:27:45 PM * @version V1.0 */ package com.oscar999.valid; import org.springframework.beans.BeanWrapper; import org.springframework.beans.BeanWrapperImpl; /** * @ClassName: BeanWrapperTest * @Description: TODO * @author oscar999 */ public class BeanWrapperTest { /** * @Title: main * @Description: TODO * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub BeanWrapper company = new BeanWrapperImpl(new Company()); company.setPropertyValue("name","oscar999 Company Inc."); //can also be done like this /*PropertyValue value = new PropertyValue("name", "Some Company Inc."); company.setPropertyValue(value);*/ BeanWrapper jim = new BeanWrapperImpl(new Employee()); jim.setPropertyValue("name", "Oscar999"); jim.setPropertyValue("salary", 1000000); company.setPropertyValue("managingDirector", jim.getWrappedInstance()); Float salary = (Float) company.getPropertyValue("managingDirector.salary"); System.out.println("salary="+salary); } } 3.4.2 內置的PropertyEditor 實現 -使用PropertyEditor設置bean的屬性 - 在MVC框架中解析Http請求參數 Class Explanation ByteArrayPropertyEditor Editor for byte arrays. Strings will simply be converted to their corresponding byte representations. Registered by default by?BeanWrapperImpl. ClassEditor Parses Strings representing classes to actual classes and the other way around. When a class is not found, an?IllegalArgumentException?is thrown. Registered by default by?BeanWrapperImpl. CustomBooleanEditor Customizable property editor for?Boolean?properties. Registered by default by?BeanWrapperImpl, but, can be overridden by registering custom instance of it as custom editor. CustomCollectionEditor Property editor for Collections, converting any source?Collection?to a given target?Collection?type. CustomDateEditor Customizable property editor for java.util.Date, supporting a custom DateFormat. NOT registered by default. Must be user registered as needed with appropriate format. CustomNumberEditor Customizable property editor for any Number subclass like?Integer,?Long,?Float,?Double. Registered by default by?BeanWrapperImpl, but can be overridden by registering custom instance of it as a custom editor. FileEditor Capable of resolving Strings to?java.io.File?objects. Registered by default by?BeanWrapperImpl. InputStreamEditor One-way property editor, capable of taking a text string and producing (via an intermediate?ResourceEditor?and?Resource) an?InputStream, so?InputStream?properties may be directly set as Strings. Note that the default usage will not close the?InputStream?for you! Registered by default by?BeanWrapperImpl. LocaleEditor Capable of resolving Strings to?Locale?objects and vice versa (the String format is?[country][variant], which is the same thing the toString() method of Locale provides). Registered by default by?BeanWrapperImpl. PatternEditor Capable of resolving Strings to?java.util.regex.Patternobjects and vice versa. PropertiesEditor Capable of converting Strings (formatted using the format as defined in the javadocs of the?java.util.Propertiesclass) to?Properties?objects. Registered by default by?BeanWrapperImpl. StringTrimmerEditor Property editor that trims Strings. Optionally allows transforming an empty string into a?null?value. NOT registered by default; must be user registered as needed. URLEditor Capable of resolving a String representation of a URL to an actual?URL?object. Registered by default by?BeanWrapperImpl. 3.5 Spring類型轉換 繼承Convert接口 /** * @Title: StringToInteger.java * @Package com.oscar999.valid * @Description: TODO * @author oscar999 * @date Sep 3, 2018 4:47:22 PM * @version V1.0 */ package com.oscar999.valid; import org.springframework.core.convert.converter.Converter; /** * @ClassName: StringToInteger * @Description: TODO * @author oscar999 */ public class StringToInteger implements Converter<String, Integer> { @Override public Integer convert(String source) { return Integer.valueOf(source); } } 3.5.2 ConverterFactory 當需要集中轉換整個類層級邏輯時，例如： 轉換Stirng 到枚舉java.lang.Enum， 繼承ConverterFactory /** * @Title: StringToEnumConverterFactory.java * @Package com.oscar999.valid * @Description: TODO * @author oscar999 * @date Sep 3, 2018 4:51:27 PM * @version V1.0 */ package com.oscar999.valid; import org.springframework.core.convert.converter.Converter; import org.springframework.core.convert.converter.ConverterFactory; /** * @ClassName: StringToEnumConverterFactory * @Description: TODO * @author oscar999 * @param <S> */ public class StringToEnumConverterFactory<S> implements ConverterFactory<String,Enum> { @Override public <T extends Enum> Converter<String, T> getConverter(Class<T> targetType) { return new StringToEnumConverter(targetType); } private final class StringToEnumConverter<T extends Enum> implements Converter<String, T> { private Class<T> enumType; public StringToEnumConverter(Class<T> enumType) { this.enumType = enumType; } public T convert(String source) { return (T) Enum.valueOf(this.enumType, source.trim()); } } } 3.5.3 GenericConverter 需要復雜的轉換實現時，考慮使用。 3.5.4 ConversionService API ConversionService定義了統一的接口用于在運行時執行類型轉換邏輯。轉換器通常在此接口之后執行。 3.5.3 配置ConversionService <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean"/> 或者 <bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean"> <property name="converters"> <set> <bean class="example.MyCustomConverter"/> </set> </property> </bean> 3.5.6 程式使用ConversionService @Service public class MyService { @Autowired public MyService(ConversionService conversionService) { this.conversionService = conversionService; } public void doIt() { this.conversionService.convert(...) } } } 3.6 Spring 欄位格式 public class MyModel { @NumberFormat(style=Style.CURRENCY) private BigDecimal decimal; } } public class MyModel { @DateTimeFormat(iso=ISO.DATE) private Date date; } } 3.8 Sprin 驗證 public class PersonForm { private String name; private int age; } } JSR-303標準 public class PersonForm { @NotNull @Size(max=64) private String name; @Min(0) private int age; } } 配置Validator <bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/> Java 的 import javax.validation.Validator; @Service public class MyService { @Autowired private Validator validator; Spring的： import org.springframework.validation.Validator; @Service public class MyService { @Autowired private Validator validator; } } 3.8.3 配置DataBinder DataBinder可以配置一個Validator, 當調用binder.validate()會觸發驗證。