Mingyang.net：用註解校正資料

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註解校正依賴的是javax.validation和hibernate-validaton。

<dependency>    <groupId>javax.validation</groupId>    <artifactId>validation-api</artifactId>    <version>1.1.0.Final</version></dependency><dependency>    <groupId>org.hibernate</groupId>    <artifactId>hibernate-validator</artifactId>    <version>5.0.1.Final</version></dependency>

啟用Spring的註解驅動：

<mvc:annotation-driven />

定義資料模型：

public class Subscriber {     @Size(min=2, max=30)     private String name;         @NotEmpty @Email    private String email;         @NotNull @Min(13) @Max(110)    private Integer age;         @Size(min=10)    private String phone;         @NotNull    private Gender gender;         @DateTimeFormat(pattern="MM/dd/yyyy")    @NotNull @Past    private Date birthday;     ...}

在控制器中用@Valid定義資料模型：

@Controllerpublic class FormController {         ...         @RequestMapping(value="form", method=RequestMethod.POST)    public String submitForm(@Valid Subscriber subscriber, BindingResult result, Model m) {        if(result.hasErrors()) {            return "formPage";        }                 m.addAttribute("message", "Successfully saved person: " + subscriber.toString());        return "formPage";    }}

在視圖中用<form:errors>顯示錯誤資訊：

<form:form action="/form" modelattribute="subscriber">    <label for="nameInput">Name: </label>    <form:input path="name" id="nameInput"></form:input>    <form:errors path="name" cssclass="error"></form:errors>    <br />         <label for="ageInput">Age: </label>    <form:input path="age" id="ageInput"></form:input>    <form:errors path="age" cssclass="error"></form:errors>    <br />         <label for="phoneInput">Phone: </label>    <form:input path="phone" id="phoneInput"></form:input>    <form:errors path="phone" cssclass="error"></form:errors>    <br />         <label for="emailInput">Email: </label>    <form:input path="email" id="emailInput"></form:input>    <form:errors path="email" cssclass="error"></form:errors>    <br />         <label for="birthdayInput">Birthday: </label>    <form:input path="birthday" id="birthdayInput" placeholder="MM/DD/YYYY">    <form:errors path="birthday" cssclass="error"></form:errors>    <br />         <label for="genderOptions">Gender: </label>    <form:select path="gender" id="genderOptions">        <form:option value="">Select Gender</form:option>        <form:option value="MALE">Male</form:option>        <form:option value="FEMALE">Female</form:option>    </form:select>    <form:errors path="gender" cssclass="error"></form:errors>    <br />         <label for="newsletterCheckbox">Newsletter? </label>    <form:checkbox path="receiveNewsletter" id="newsletterCheckbox"></form:checkbox>    <form:errors path="receiveNewsletter" cssclass="error"></form:errors>    <br /><br />    <input type="submit" value="Submit" /></form:input></form:form>

如何定義校正資訊？最簡單的方式是用message參數：

@Size(min=10, message="Phone number must be at least 10 characters")

但是這不能實現國際化文文書處理。用messageSource可以實現國際化文字：

<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">    <property name="basename" value="messages"/></bean>

然後在src/main/resources下建立messages.properties，用下面的格式覆蓋預設的校正資訊：

{ValidationClass}.{modelObjectName}.{field}

例如：

Size=the {0} field must be between {2} and {1} characters longSize.subscriber.name=Name must be between {2} and {1} charactersSize.subscriber.phone=Phone must be at least {2} characters Min.subscriber.age=You must be older than {1}Max.subscriber.age= Sorry, you have to be younger than {1} Email=Email address not validPast=Date must be in the past NotEmpty=Field cannot be left blankNotNull=Field cannot be left blank typeMismatch=Invalid formatmethodInvocation.myRequest.amount=Invalid format

注意下面這段話，說明了搜尋校正資訊的順序：

For example, if the age field of our “subscriber” model object fails the “NotNull” validation, the “NotNull.subscriber.age” message would be looked up. If the message isn’t found, “NotNull.subscriber” would be looked for. Finally, if not found, “NotNull” message would be looked for. If that also isn’t found, the default message (what we saw above) would be rendered. 

http://codetutr.com/2013/05/28/spring-mvc-form-validation/