[Java知识库]SpringBoot 官方文档示例：(8)访问应用程序参数的方法

1.创建bean,把ApplicationArguments类型的参数传递给bean的构造方法：

package cn.edu.tju.domain;

import org.springframework.boot.ApplicationArguments;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class Person {
    private String username;

    public String getUsername() {
        return username;
    }

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

    public Person(ApplicationArguments args){
        List<String> argList=args.getOptionValues("username");
        this.username=argList.get(0);
    }
}

这个实体类的Person构造方法中，args参数就可以用来获取通过命令行传递过来的参数。
2.controller中注入上述bean

package cn.edu.tju.controller;

import cn.edu.tju.domain.Person;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {
    @Autowired
    private Person person;
    @RequestMapping("getUsername")
    public String getUsername(){
        return person.getUsername();
    }
}

3.打包成jar包，完整pom如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.edu.tju</groupId>
    <artifactId>springboot266</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.6</version>
    </parent>
    <!-- Additional lines to be added here... -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
        <groupId>cglib</groupId>
        <artifactId>cglib</artifactId>
        <version>3.3.0</version>
    </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>cn.edu.tju.Start</mainClass>
                </configuration>

            </plugin>
        </plugins>
    </build>


</project>

4.带参数运行jar包：

java -jar D:\springboot266\target\springboot266-1.0-SNAPSHOT.jar --username=newton

5.运行结果，可以看出运行时输入的参数newton被成功注入到了bean中

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