Spring @Value 注解使用总结

application.properties 配置文件

answer.ftp.ip=127.0.0.1
answer.max.thread.size=10
answer.email.senders=answer_ljm@163.com,1072594307@qq.com
answer.email=answer_ljm@163.com

本地文件 config.txt

userName: AnswerAIL
password: ******
email: answer_ljm@163.com

文件位置： resources/config.txt

package com.answer.ai.common;

public interface Constant {
    int DEFAULT_VALUE = -1;
}

@Service("answerService")
public class AnswerService {
    @Getter
    @Setter
    private String authorName = "AnswerAIL";

    public int threadMaxSize() {
        return 10;
    }

    public int maxSize(int size) {
        int threadMaxSize = threadMaxSize();
        return threadMaxSize > size ? threadMaxSize : size;
    }

    public int defaultValue() {
        return Constant.DEFAULT_VALUE;
    }
}

@Component
public class ValueSummary implements InitializingBean {

    /**
     * 注入一个配置项
     */
    @Value("${answer.ftp.ip}")
    private String ftpIp;

    /**
     * 调用容器的一个bean的方法获取值
     */
    @Value("#{answerService.threadMaxSize()}")
    private int threadMaxSize;

    /**
     * 调用容器的一个bean的方法，且传入一个配置项的值作为参数
     */
    @Value("#{answerService.maxSize(${answer.max.thread.size})}")
    private int maxSize;

    /**
     * 注入其他 Bean 属性
     * */
    @Value("#{answerService.authorName}")
    private String authorName;

    /**
     * 简单的运算
     */
    @Value("#{${answer.max.thread.size} <= 0 ? ${answer.max.thread.size} : 0}")
    private int minSize;

    /**
     * 注入配置项, 默认值: {@link com.answer.ai.common.Constant#DEFAULT_VALUE}
     * `@Value("${answer.max.thread.size:#{T(com.answer.ai.common.Constant).DEFAULT_VALUE}}")`
     * */
    @Value("${answer.max.thread.size:#{answerService.defaultValue()}}")
    private int maxThreadSize;

    /**
     * 注入普通字符串
     * */
    @Value("Do Not Repeat Yourself")
    private String stringConstTxt;

    /**
     * 注入操作系统属性(与 <b>System.getProperties().getProperty("os.name")</b> 类似)
     * */
    @Value("#{systemProperties['os.name']}")
    private String systemOsName;

    /**
     * 注入操作系统属性集对象(与 <b>System.getProperties()</b> 类似)
     * */
    @Value("#{systemProperties}")
    private Properties properties;

    /**
     * 注入表达式结果(#{ } 里面写表 SpEL 达式)
     * */
    @Value("#{T(com.answer.ai.common.Constant).DEFAULT_VALUE}")
    private int defaultValueConstant;

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

    /**
     * 注入本地文件资源
     * */
    @Value("classpath:config.txt")
    private org.springframework.core.io.Resource localFileSource;

    /**
     * 注入网络 URL 资源
     * */
    @Value("http://www.baidu.com")
    private org.springframework.core.io.Resource baiduSource;

    @Value("#{'${answer.email.senders}'.split(',')}")
    private List<String> senders;

    private static String userName;
    private static String email;

    /**
     * 如果变量 answer.userName 未配置, 则设置默认值为: AnswerAIL
     * */
    @Value("${answer.userName:AnswerAIL}")
    public void setUserNameme(String userName) {
        ValueSummary.userName = userName;
    }

    /**
     * 注入静态变量
     * */
    @Value("${answer.email}")
    public void setEmail(String email) {
        ValueSummary.email = email;
    }

    /**
     * 所有配置值也可以从 environment 对象中取
     * */
    @Autowired
    private org.springframework.core.env.Environment environment;

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("answer.ftp.ip: " + ftpIp);
        System.out.println("Thread Max Size: " + threadMaxSize);
        System.out.println("Max Size: " + maxSize);
        System.out.println("Min Size: " + minSize);
        System.out.println("Author Name: " + authorName);
        System.out.println("Max Thread Size: " + maxThreadSize);
        System.out.println("stringConstTxt: " + stringConstTxt);
        System.out.println("System OS Name: " + systemOsName);
        System.out.println("System Properties Size: " + properties.size());
        System.out.println("System Properties Size: " + System.getProperties().size());
        System.out.println("Default Value Constant: " + defaultValueConstant);
        System.out.println("Random Number: " + randomNumber);

        System.out.println();
        System.out.println("Local File Source: \n" + IOUtils.toString(localFileSource.getInputStream()));
        System.out.println("Baidu Source: " + IOUtils.toString(baiduSource.getInputStream()));

        System.out.println("active profiles: " + JacksonUtil.toJsonString(environment.getActiveProfiles()));
        System.out.println("answer.email: " + environment.getProperty("answer.email"));

        System.out.println("answer.email.senders: " + senders);

        System.out.println("answer.userName: " + userName);
        System.out.println("answer.email: " + email);
    }
}

程序运行结果

answer.ftp.ip: 127.0.0.1
Thread Max Size: 10
Max Size: 10
Min Size: 0
Author Name: AnswerAIL
Max Thread Size: 10
stringConstTxt: Do Not Repeat Yourself
System OS Name: Windows 10
System Properties Size: 62
System Properties Size: 62
Default Value Constant: -1
Random Number: 11.837094128616087

Local File Source: 
userName: AnswerAIL
password: ******
email: answer_ljm@163.com

Baidu Source: ...

active profiles: ["dev"]
answer.email: answer_ljm@163.com
answer.email.senders: [answer_ljm@163.com, 1072594307@qq.com]
answer.userName: AnswerAIL
answer.email: answer_ljm@163.com

​​github 地址​​