Spring boot configuration

Run a Spring boot application

Usually a Spring boot application can be compile and run with Intellij IDEA or any other IDE. However, there are other ways to starting a Spring application with command line. This is especially useful if the application is on the remote server.

1. mvn spring-boot:run

2. mvn clean package, then go to the target folder, run java -jar ***-SNAPSHOT.jar

Configuration

A database configuration example:

spring.datasource.url: jdbc:mysql://127.0.0.1:3306/
spring.datasource.username: root
spring.datasource.password: root
spring.datasource.driver-class-name: com.mysql.jdbc

• Change the default port: server.port=8081
• server.servlet.context-path=/luckymoney

Then we need to go to localhost:8081/luckymoney/hello.

We can also create a new configuration file, for example, application.yml

server:
  port: 8081
  servlet:
    context-path: /luckymoney

minMoney: 1
description: At least ${minMoney} dollar

Then, in our application, we can use it in the program.

@RestController
public  class HelloController {
    @Value("${minMoney}")
    private BigDecimal minMoney;
    
    @Value("${description}")
    private String description;
    
    @GetMapping("/hello")
    public String say(){
        return "minMoney: " + minMoney + ", means " + description;
    }
}

Using configuration file, config with object

Step 1: put the values in the application.yml file inside a whole parent value.

limit:
  minMoney: 2
  maxMoney: 9999
  description: At least ${limit.minMoney} dollar

Step 2: Create a java file and @ConfigurationProperties(prefix = “***”)

@ConfigurationProperties(prefix = "limit")
@Component
public class LimitConfig {

    private BigDecimal minMoney;

    private BigDecimal maxMoney;

    private String description;

    public BigDecimal getMinMoney() {
        return minMoney;
    }

    public void setMinMoney(BigDecimal minMoney) {
        this.minMoney = minMoney;
    }

    public BigDecimal getMaxMoney() {
        return maxMoney;
    }

    public void setMaxMoney(BigDecimal maxMoney) {
        this.maxMoney = maxMoney;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

Step 3: @Autowired and use it

@RestController
public class HelloController {

    @Autowired
    private LimitConfig limitConfig;


    @GetMapping("/hello")
    public String say(){
        return "Description: " + limitConfig.getDescription();
    }
}

Separate development environment and production environment

1. Create/copy two more configuration files, application-dev.yml and application-prod.yml. Then give any configuration in each file as desired.

2. Change the original application.yml file.

spring:
  profiles:
    active: dev

1. When get to the production stage, add a parameter when running the jar file.

   • mvn clean package
   • java -jar [-Dspring.profiles.active=prod] luckymoney-0.01-SNAPSHOT.jar