Spring EL运算符实例 - Spring教程

Spring EL支持大多数标准的数学，逻辑和关系运算符。 例如，

1. 关系运算符 – 等于 (==, eq), 不等于 (!=, ne), 小于 (<, lt), 小于或等于 (<= , le), 大于 (>, gt), 和大于或等于 (>=, ge).
2. 逻辑运算符 – 且, 或, 非 (!).
3. 数学运算符 – 加法(+), 减法 (-), 乘法 (*), 除法(/), 除模(%) 和指数幂 (^).

Spring EL以注解的形式

这个例子说明了如何在 SpEL 中使用运算符。

package com.yiibai.core;

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

@Component("customerBean")
public class Customer {

    //Relational operators

    @Value("#{1 == 1}") //true
    private boolean testEqual;

    @Value("#{1 != 1}") //false
    private boolean testNotEqual;

    @Value("#{1 < 1}") //false
    private boolean testLessThan;

    @Value("#{1 <= 1}") //true
    private boolean testLessThanOrEqual;

    @Value("#{1 > 1}") //false
    private boolean testGreaterThan;

    @Value("#{1 >= 1}") //true
    private boolean testGreaterThanOrEqual;

    //Logical operators , numberBean.no == 999

    @Value("#{numberBean.no == 999 and numberBean.no < 900}") //false
    private boolean testAnd;

    @Value("#{numberBean.no == 999 or numberBean.no < 900}") //true
    private boolean testOr;

    @Value("#{!(numberBean.no == 999)}") //false
    private boolean testNot;

    //Mathematical operators

    @Value("#{1 + 1}") //2.0
    private double testAdd;

    @Value("#{'1' + '@' + '1'}") //1@1
    private String testAddString;

    @Value("#{1 - 1}") //0.0
    private double testSubtraction;

    @Value("#{1 * 1}") //1.0
    private double testMultiplication;

    @Value("#{10 / 2}") //5.0
    private double testDivision;

    @Value("#{10 % 10}") //0.0
    private double testModulus ;

    @Value("#{2 ^ 2}") //4.0
    private double testExponentialPower;

    @Override
    public String toString() {
        return "Customer [testEqual=" + testEqual + ", testNotEqual="
                + testNotEqual + ", testLessThan=" + testLessThan
                + ", testLessThanOrEqual=" + testLessThanOrEqual
                + ", testGreaterThan=" + testGreaterThan
                + ", testGreaterThanOrEqual=" + testGreaterThanOrEqual
                + ", testAnd=" + testAnd + ", testOr=" + testOr + ", testNot="
                + testNot + ", testAdd=" + testAdd + ", testAddString="
                + testAddString + ", testSubtraction=" + testSubtraction
                + ", testMultiplication=" + testMultiplication
                + ", testDivision=" + testDivision + ", testModulus="
                + testModulus + ", testExponentialPower="
                + testExponentialPower + "]";
    }

}

package com.yiibai.core;

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

@Component("numberBean")
public class Number {

    @Value("999")
    private int no;

    public int getNo() {
        return no;
    }

    public void setNo(int no) {
        this.no = no;
    }

}

执行

Customer obj = (Customer) context.getBean("customerBean");
System.out.println(obj);

输出结果

Customer [testEqual=true, testNotEqual=false, testLessThan=false, testLessThanOrEqual=true, testGreaterThan=false, testGreaterThanOrEqual=true, testAnd=false, testOr=true, testNot=false, testAdd=2.0, testAddString=1@1, testSubtraction=0.0, testMultiplication=1.0, testDivision=5.0, testModulus=0.0, testExponentialPower=4.0]

Spring EL以XML形式

请参阅在XML文件定义bean的等效版本。在XML中，类似 < 小于符号不支持，应该使用下面所示文本形式，例如文本等值， ('<' = 'lt') 和 ('<=' = 'le').

<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="testEqual" value="#{1 == 1}" />
      <property name="testNotEqual" value="#{1 != 1}" />
      <property name="testLessThan" value="#{1 lt 1}" />
      <property name="testLessThanOrEqual" value="#{1 le 1}" />
      <property name="testGreaterThan" value="#{1 > 1}" />
      <property name="testGreaterThanOrEqual" value="#{1 >= 1}" />

      <property name="testAnd" value="#{numberBean.no == 999 and numberBean.no lt 900}" />
      <property name="testOr" value="#{numberBean.no == 999 or numberBean.no lt 900}" />
      <property name="testNot" value="#{!(numberBean.no == 999)}" />

      <property name="testAdd" value="#{1 + 1}" />
      <property name="testAddString" value="#{'1' + '@' + '1'}" />
      <property name="testSubtraction" value="#{1 - 1}" />
      <property name="testMultiplication" value="#{1 * 1}" />
      <property name="testDivision" value="#{10 / 2}" />
      <property name="testModulus" value="#{10 % 10}" />
      <property name="testExponentialPower" value="#{2 ^ 2}" />

    </bean>

    <bean id="numberBean" class="com.yiibai.core.Number">
        <property name="no" value="999" />
    </bean>

</beans>

下载代码 - http://pan.baidu.com/s/1MLG1w