Spring EL正则表达式实例 - Spring教程

Spring EL支持正则表达式，可使用一个简单的关键词“matches”。如下实例，

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

它测试'100'是否是通过正则表达式‘\d+‘测试过的一个有效的数字。

Spring EL以注解的形式

请参阅下面的 Spring EL 正则表达式的例子，这里有部分掺入三元运算符，这使得 Spring EL 非常灵活，功能强大。下面的例子应该是不言自明的。

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;

    //...
}

输出

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

Spring EL以XML的形式

请参阅在XML文件定义bean的等效版本。

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <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>

</beans>

下载代码 – http://pan.baidu.com/s/1jHklXt0

参考

1. Spring EL三元运算符(if-then-else)实例