如何处理以前没有遇到过的新需求（如给用户发送邮件），需要积累解决问题的能力（实习的时候可以边问边查，做自己的项目只能自己去查，那么如何高效检索并善用AI）,并形成方法论，以便提高能力

发现 Claude 之前教的在Service Layer 中使用 @AuthenticatedPrincipal 的方法不正确，当时没有及时测试导致现在有若干地方需要修改！！！使用但不要盲目相信

idea无法热加载， 根据

Perperlexity

In IntelliJ IDEA, ensure that the project is set to build automatically. Go to File -> Settings -> Build, Execution, Deployment -> Compiler, and check the option Build project automatically. This setting allows the IDE to compile changes without needing to manually trigger a build each time

以及

Spring Boot DevTools Live Reload Not Working

两者结合解决

进度：

change user nickname

bind email

本周写论文(实验室横向)，无其他进展

to do:

query comment (recursive query, complex)

Space in application.properties value

1. Leading and trailing spaces: By default, leading and trailing spaces in property values are trimmed. If you need to preserve them, you can use quotation marks.

2. Spaces within the value: Spaces within the value are preserved normally.

3. Escaping: If you want to be explicit about including spaces, you can escape them with a backslash.

Here are some examples:

# Space in the middle (works fine)
app.name=My Application

# Preserving leading/trailing spaces with quotes
app.description="  This is a description with spaces  "

# Escaping spaces (not necessary, but valid)
app.path=C:\Program\ Files\My\ App

# Multiline values
app.multiline=This is a long \
              property value that \
              spans multiple lines

If you’re having issues with spaces in your application.properties file, you might want to double-check how you’re reading the properties in your application. Some methods of reading properties may handle spaces differently.

Store Credentials in spring boot

1. Basic approach (not recommended for production):

database.username=myuser
database.password=mypassword

2. Using environment variables: Instead of hardcoding credentials, you can reference environment variables:

database.username=${DB_USERNAME}
database.password=${DB_PASSWORD}

Then set these environment variables on your system or in your deployment environment.

3. Using Spring Boot’s config server: For more secure credential management, especially in production, consider using Spring Cloud Config Server.

4. Encryption: Spring Boot supports property encryption. You can use tools like Jasypt to encrypt sensitive properties:

database.username=ENC(encrypted_username)
database.password=ENC(encrypted_password)

5. Externalized configuration: Store sensitive data in external files and reference them:

spring.config.import=file:/path/to/secure/credentials.properties

For production environments, I recommend using a secrets management system like HashiCorp Vault, AWS Secrets Manager, or Azure Key Vault. These provide more secure ways to manage and access sensitive information.

Would you like me to elaborate on any of these approaches or provide a more detailed example of implementing one of them in a Spring Boot application?

.env in spring boot

Using environment variables in a Spring Boot application is a good practice for managing sensitive information like credentials. There are a few ways to work with environment variables, and creating a .env file is one approach, though it requires some additional setup. Let’s go through the process:

1. Using system environment variables:

   This is the most straightforward method. You set the variables in your operating system or deployment environment, and Spring Boot can access them directly.

   For example, you might set variables like this:

   export DB_USERNAME=myuser
   export DB_PASSWORD=mypassword
   

   Then in your application.properties:

   spring.datasource.username=${DB_USERNAME}
   spring.datasource.password=${DB_PASSWORD}
   

2. Using a .env file:

   While Spring Boot doesn’t natively support .env files, you can use a library like dotenv-java to load variables from a .env file. Here’s how:

   // Add this dependency to your pom.xml
   <dependency>
       <groupId>io.github.cdimascio</groupId>
       <artifactId>dotenv-java</artifactId>
       <version>2.3.1</version>
   </dependency>
   
   // In your main application class
   import io.github.cdimascio.dotenv.Dotenv;
   
   @SpringBootApplication
   public class MyApplication {
   
       public static void main(String[] args) {
           Dotenv dotenv = Dotenv.load();
           System.setProperty("DB_USERNAME", dotenv.get("DB_USERNAME"));
           System.setProperty("DB_PASSWORD", dotenv.get("DB_PASSWORD"));
   
           SpringApplication.run(MyApplication.class, args);
       }
   }
   
   // Create a .env file in your project root
   DB_USERNAME=myuser
   DB_PASSWORD=mypassword
   
   // In your application.properties
   spring.datasource.username=${DB_USERNAME}
   spring.datasource.password=${DB_PASSWORD}
   

​ Remember to add .env to your .gitignore file to prevent committing sensitive information to version control.

3. Command-line arguments:

You can also pass environment variables as command-line arguments when running your application:

java -jar myapp.jar --spring.datasource.username=myuser --spring.datasource.password=mypassword

Remember, while using a .env file can be convenient for development, it’s generally not recommended for production environments. In production, it’s better to use system environment variables, secret management systems, or cloud provider-specific solutions.

One Time Password

@PathVariable

To use path parameters with a POST mapping in Spring Boot, you can use the @PathVariable annotation along with @PostMapping. Here’s a brief example:

@RestController
@RequestMapping("/api")
public class MyController {

    @PostMapping("/users/{id}")
    public ResponseEntity<String> createUser(@PathVariable Long id, @RequestBody User user) {
        // Process the user creation with the given id
        return ResponseEntity.ok("User created with ID: " + id);
    }
}

In this example:

1. The @PostMapping annotation defines the endpoint for POST requests.
2. The {id} in the path is a path variable.
3. The @PathVariable Long id parameter in the method signature captures the value of the {id} path variable.
4. You can also include a request body using @RequestBody if needed.

To call this endpoint, you would send a POST request to a URL like /api/users/123, where 123 is the ID.

Would you like me to explain any part of this in more detail or show you how to handle multiple path variables?

References

Guide to Spring Email