利用@Value注解为bean的属性赋值方法总结

@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.ANNOTATioN_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Value {
  
    String value();
}

@Value("liqb")
private String name; // 注入普通字符串

@Value("#{systemProperties['os.name']}")
private String systemPropertiesName; // 注入操作系统属性

@Value("#{ T(java.lang.Math).random() * 100.0 }")
private double randomNumber; //注入SpEL表达式结果

@Value("#{person.name}")
private String username; // 注入其他bean中属性的值，即注入person对象的name属性中的值

@Value("classpath:/config.properties")
private Resource resourceFile; // 注入文件资源

@Value("Http://www.baidu.com")
private Resource url; // 注入URL资源

person.nickName=liqb

package com.tianxia.springannotation.config;

import com.tianxia.springannotation.entity.Person;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;


@Configuration
@PropertySource(value={"classpath:/person.properties"})
public class MainConfigOfPropertyValues {

    @Bean
    public Person person() {
        return new Person();
    }
}

package com.tianxia.springannotation.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.beans.factory.annotation.Value;

import java.io.Serializable;


@Data
@NoArgsConstructor
@AllArgsConstructor
public class Person implements Serializable {

    
    private String name;

    
    private Integer age;

    
    @Value("${person.nickName}")
    private String nickName;

    public Person(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
}

server.name=server1,server2,server3
author.name=liqb

package com.tianxia.springannotation.config;

import com.tianxia.springannotation.entity.Person;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;


@Configuration
@PropertySource(value={"classpath:/person.properties"})
public class MainConfigOfPropertyValues {

    @Bean
    public Person person() {
        return new Person();
    }
}

@Value("${author.name:liqb}")
private String name;

// SpEL：调用字符串Hello World的concat方法
@Value("#{'Hello World'.concat('!')}")
private String helloWorld;

// SpEL：调用字符串的getBytes方法，然后再调用其length属性
@Value("#{'Hello World'.bytes.length}")
private String helloWorldBytes;

// SpEL：传入一个字符串，根据","切分后插入列表中， #{}和${}配合使用时，注意不能反过来${}在外面，而#{}在里面
@Value("#{'${server.name}'.split(',')}")
private List<String> severs;