Spring EL正則表達式實例

Spring EL支持正則表達式，可使用一個簡單的關鍵詞「matches」。如下實例，

@Value("#{'100' matches '\\d+' }")
private boolean isDigit;

它測試'100'是否是通過正則表達式‘\\d+‘測試過的一個有效的數字。

Spring EL以註解的形式

請參閱下面的 Spring EL 正則表達式的例子，這裏有部分摻入三元運算符，這使得 Spring EL 非常靈活，功能強大。

下面的例子應該是不言自明的。

package com.yiibai.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("customerBean")
public class Customer {

// email regular expression
String emailRegEx = "^\[\_A-Za-z0-9-\]+(\\\\.\[\_A-Za-z0-9-\]+)" +
        "\*@\[A-Za-z0-9\]+(\\\\.\[A-Za-z0-9\]+)\*(\\\\.\[A-Za-z\]{2,})$";

// if this is a digit?
@Value("#{'100' matches '\\\\d+' }")
private boolean validDigit;

// if this is a digit + ternary operator
@Value("#{ ('100' matches '\\\\d+') == true ? " +
        "'yes this is digit' : 'No this is not a digit'  }")
private String msg;

// if this emailBean.emailAddress contains a valid email address?
@Value("#{emailBean.emailAddress matches customerBean.emailRegEx}")
private boolean validEmail;

//getter and setter methods, and constructor    

}

package com.yiibai.core;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("emailBean")
public class Email {

@Value("[email protected]")
String emailAddress;

//...

}

輸出

Customer [isDigit=true, msg=yes this is digit, isValidEmail=true]

Spring EL以XML的形式

請參閱在XML文件定義bean的等效版本。

<bean id="customerBean" class="com.yiibai.core.Customer">
  <property name="validDigit" value="#{'100' matches '\\d+' }" />
  <property name="msg"
    value="#{ ('100' matches '\\d+') == true ? 'yes this is digit' : 'No this is not a digit'  }" />
  <property name="validEmail"
    value="#{emailBean.emailAddress matches '^\[\_A-Za-z0-9-\]+(\\.\[\_A-Za-z0-9-\]+)\*@\[A-Za-z0-9\]+(\\.\[A-Za-z0-9\]+)\*(\\.\[A-Za-z\]{2,})$' }" />
</bean>

<bean id="emailBean" class="com.yiibai.core.Email">
  <property name="emailAddress" value="[email protected]" />
</bean>

下載代碼 –  http://pan.baidu.com/s/1jHklXt0

參考

1. Spring EL三元運算符(if-then-else)實例