spring expression language(SEL)

User.java

package com.test.spring.model;

public class User {
	private String username;
	private String password;

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}
}

 

测试类

SpELTest_Simple.java

package com.test.spring.spel;

import org.junit.Test;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

import com.test.spring.model.User;

public class SpELTest_Simple {
	@Test
	public void test01() {
		ExpressionParser parser = new SpelExpressionParser();
		Expression exp = parser.parseExpression("'Hello,World'");
		System.out.println((String)exp.getValue());
	}
	
	@Test
	public void test02() {
		
		User u = new User();
		u.setUsername("zhangsan");
		
		EvaluationContext context = new StandardEvaluationContext(u);
		
		ExpressionParser parser = new SpelExpressionParser();
		Expression exp = parser.parseExpression("username"); //u.getUsername()
		System.out.println((String)exp.getValue(context));
		System.out.println((String)exp.getValue(u));
	}
	
	//eval("alert('ok');");
}

 

运行结果：

Hello,World

zhangsan

zhangsan

MyBean.java

package com.test.spring.spel;

public class MyBean {
	private double randomNumber;
	private String userRegion;
	public double getRandomNumber() {
		return randomNumber;
	}
	public void setRandomNumber(double randomNumber) {
		this.randomNumber = randomNumber;
	}
	public String getUserRegion() {
		return userRegion;
	}
	public void setUserRegion(String userRegion) {
		this.userRegion = userRegion;
		//System.getProperty("user.country");
	}
	
}

 

beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd">

	<bean id="myBean" class="com.test.spring.spel.MyBean">
		<property name="randomNumber" value="#{T(java.lang.Math).random() * 100}"></property>
		<property name="userRegion" value="#{systemProperties['user.country']}"></property>
	</bean>

</beans>

 

测试类

SpELTest.java

package com.test.spring.spel;

import javax.annotation.Resource;

import org.junit.Test;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.AbstractJUnit4SpringContextTests;

@ContextConfiguration("classpath:beans.xml")
public class SpELTest extends AbstractJUnit4SpringContextTests {

	private MyBean myBean;

	public MyBean getMyBean() {
		return myBean;
	}

	@Resource(name = "myBean")
	public void setMyBean(MyBean myBean) {
		this.myBean = myBean;
	}

	@Test
	public void test01() {
		System.out.println(myBean.getRandomNumber());
		System.out.println(myBean.getUserRegion());
	}

}

 

运行结果：

89.28062809767297

CN