SpringBoot属性注入的两种方法

@Component
@PropertySource("classpath:user.properties")
public class UserInfo {
 @Value("${user.username}")
 private String username;

 @Value("${user.password}")
 private String password;

 @Value("${user.age}")
 private Integer age;

 @Override
 public String toString() {
 return "UserInfo{" +
  "username='" + username + '\'' +
  ", password='" + password + '\'' +
  ", age=" + age +
  '}';
 }
}

user.username='admin'
user.password='123'
user.age=88

@SpringBootTest
public class UserInfoTest {
 @Autowired
 UserInfo userInfo;
 @Test
 public void user(){
 System.out.println(userInfo.toString());
 }
}

UserInfo{username=''admin'', password=''123'', age=88}

java.lang.IllegalStateException: Failed to load ApplicationContext
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userInfo': Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'user.username' in value "${user.username}"

@Component
@PropertySource("classpath:user.properties")
@ConfigurationProperties(prefix = "user")
public class UserInfo {
// @Value("${user.username}")
 private String username;

// @Value("${user.password}")
 private String password;

// @Value("${user.age}")
 private Integer age;


 public String getUsername() {
 return username;
 }

 public String getPassword() {
 return password;
 }

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

 public Integer getAge() {
 return age;
 }

 public void setAge(Integer age) {
 this.age = age;
 }

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

 @Override
 public String toString() {
 return "UserInfo{" +
  "username='" + username + '\'' +
  ", password='" + password + '\'' +
  ", age=" + age +
  '}';
 }
}