springboot-获取yaml文件的3种方式

springboot-获取yaml文件的3种方式

1. 方法一

   ```java
   //获取单个.yaml数据的值
   //方法一：
   //1.在当前类里面定义属性
   //2.在属性上面使用@Value注解并在括号里面写入定义的属性名
   //3.在定义的属性名要和.yaml 文件里的属性名一致
   @Value("${lesson}")
   private String lesson;
   
    System.out.println(lesson);
   ```

2. 方法二

   ```java
   //方法二：(封装后读取)
   //1.在当前类定义一个Environment类型的属性，并在这个属性的上面加上@Autowired注解
    @Autowired
   private Environment env;
   
   System.out.println(env.getProperty("Books.id"));
   System.out.println(env.getProperty("Books.BookName"));
   System.out.println(env.getProperty("Books.BookPrice"));
   System.out.println(env.getProperty("Books.Stock"));
   System.out.println(env.getProperty("BookName"));
   ```

3. 方法三

```java
//方法三：（封装后读取）
//1.一般用于实体类的获取
//2.要在实体类中标明一个注解:比如 @Component（确定是一个bean对象）
//3.然后再配置一个@ConfigurationProperties(prefix = "books")注解
//4.@ConfigurationProperties：是.yaml文件中的属性
//5、prefix :是获取.yaml文件中的前缀(.yaml 文件的头属性)
//@ConfigurationProperties(prefix = "books")
@Autowired
private Books books;

System.out.println(books);
System.out.println(books.getId());
```

application.yaml

```yaml
#.yaml:数据序列格式化
#注重：数据
# 在冒号的后面要加上空格
#区分大小写

lesson: springboot

hello: hello SpringBoot
server:
  port: 89
logging:
  level:
    root: info


Books:
  id: 1
  BookName: SpringBoot
  BookPrice: 89.9
  Stock: 99

BookName:
  -java
  -spring5
  -mysql
  -mybatis
  -springMVC
  -SpringBoot
```

BookController.java (执行类)

```java
package com.xiao.springbootdemo.controller;

import com.xiao.springbootdemo.daoMain.Books;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Author :信仰
 * @Date :2023/2/25 8:11
 */

@RestController
@RequestMapping("/books")
public class BookController {


    //获取单个.yaml数据的值
    //方法一：
    //1.在当前类里面定义属性
    //2.在属性上面使用@Value注解并在括号里面写入定义的属性名
    //3.在定义的属性名要和.yaml 文件里的属性名一致
    @Value("${lesson}")
    private String lesson;
    @Value("${hello}")
    private String hello;


    //方法二：(封装后读取)
    //1.在当前类定义一个Environment类型的属性，并在这个属性的上面加上@Autowired注解
     @Autowired
    private Environment env;


     //方法三：（封装后读取）
    //1.一般用于实体类的获取
    //2.要在实体类中标明一个注解:比如 @Component（确定是一个bean对象）
    //3.然后再配置一个@ConfigurationProperties(prefix = "books")注解
    //4.@ConfigurationProperties：是.yaml文件中的属性
    //5、prefix :是获取.yaml文件中的前缀(.yaml 文件的头属性)
    //@ConfigurationProperties(prefix = "books")
    @Autowired
    private Books books;



    @GetMapping("/{id}")
    public String getBookId(@PathVariable Integer id){
        System.out.println("id="+id);

        //方法一的输出语句
        System.out.println(lesson);
        System.out.println(hello);


        System.out.println("==========");

        //方法二的输出语句
        System.out.println(env.getProperty("lesson"));
        System.out.println(env.getProperty("Books.id"));
        System.out.println(env.getProperty("Books.BookName"));
        System.out.println(env.getProperty("Books.BookPrice"));
        System.out.println(env.getProperty("Books.Stock"));
        System.out.println(env.getProperty("BookName"));

        System.out.println("==========");

        //方法三的输出语句
        System.out.println(books);
        System.out.println(books.getId());

        return "hello springboot!";
    }


}
```

实体类：

```java
package com.xiao.springbootdemo.daoMain;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;

/**
 * @Author :信仰
 * @Date :2023/2/25 11:35
 */


@ConfigurationProperties(prefix = "books")
@Component

public class Books {
    private Integer id;
    private String BookName;
    private Double BookPrice;
    private Integer Stock;

    public Books() {
    }

    public Books(Integer id, String bookName, Double bookPrice, Integer stock) {
        this.id = id;
        BookName = bookName;
        BookPrice = bookPrice;
        Stock = stock;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getBookName() {
        return BookName;
    }

    public void setBookName(String bookName) {
        BookName = bookName;
    }

    public Double getBookPrice() {
        return BookPrice;
    }

    public void setBookPrice(Double bookPrice) {
        BookPrice = bookPrice;
    }

    public Integer getStock() {
        return Stock;
    }

    public void setStock(Integer stock) {
        Stock = stock;
    }

    @Override
    public String toString() {
        return "Books{" +
                "id=" + id +
                ", BookName='" + BookName + '\'' +
                ", BookPrice=" + BookPrice +
                ", Stock=" + Stock +
                '}';
    }
}
```