Java 读取yaml文件-马育民老师

# 说明

Java 读取yaml文件，有以下方法：

- snakeyaml，springboot使用该库

- jackson，底层使用snakeyaml，使用 API 与 操作 JSON相同

本文讲解 snakeyaml 使用方法

# 添加依赖

```
<dependency>
  <groupId>org.yaml</groupId>
  <artifactId>snakeyaml</artifactId>
  <version>1.27</version>
</dependency>
```

# 例子1

读取 yaml 文件，并返回 `Map`

### yaml配置文件内容

在 `resources` 目录下创建 `application.yml` 配置文件，内容如下：

```
server:
  port: 8080
  servlet:
    context-path: /
spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
```

### 代码

```
LoaderOptions options = new LoaderOptions();
options.setAllowDuplicateKeys(false);
Yaml yaml = new Yaml(options);

InputStream inputStream = this.getClass()
        .getClassLoader()
        .getResourceAsStream(path);
Map<String, Object> map = yaml.load(inputStream);
```

# 例子2

将yaml文件解析成javabean

### 配置文件

```
userId: 1
username: "lisi"
password: '123456'
address:
  province: 山东
  city: "济南 : ss"
hobbyList:
  - 游泳
  - 跑步
```

### 代码

```
import java.io.InputStream;
import java.sql.Timestamp;
import java.util.List;
import java.util.Objects;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.ToString;
import org.yaml.snakeyaml.Yaml;

public class Client {

public static void main(String[] args) {
    InputStream resource = Client.class.getClassLoader().getResourceAsStream("User.yaml");
    if (Objects.nonNull(resource)) {
      Yaml yaml = new Yaml();
      User user = yaml.loadAs(resource, User.class);
      System.out.println(user.getClass());
      System.out.println(user);
    }
  }

@Setter
  @Getter
  @ToString
  @AllArgsConstructor
  @NoArgsConstructor
  public static class User {

private String userId;
    private String username;
    private String password;
    private Timestamp createDate;
    private Address address;
    private List<String> hobbyList;
  }

@Setter
  @Getter
  @ToString
  @AllArgsConstructor
  @NoArgsConstructor
  public static class Address {

private String province;
    private String city;
  }
}
```

# 三条横线将一个文件分成多个配置

### 配置文件

```
userId: 1
username: "lisi"
password: '123456'
address:
  province: 山东
  city: "济南 : ss"
hobbyList:
  - 游泳
  - 跑步
---
userId: 2
username: "lisi2"
password: '123456'
address:
  province: 河南
  city: "郑州 : ss"
hobbyList:
  - 下棋
  - 画画

...
```

- 在单一文件中，可用连续三个横线 `---` 区分多个文件。
- 还有选择性的连续三个点号 `...` 用来表示文件结尾。

```
import org.yaml.snakeyaml.Yaml;
import java.io.InputStream;
import java.util.Objects;

public class TestYaml {
    public static void main(String[] args) {
        InputStream resource = TestYaml.class.getClassLoader().getResourceAsStream("User.yaml");
        if (Objects.nonNull(resource)) {
            Yaml yaml = new Yaml();
            Iterable<Object> objects = yaml.loadAll(resource);
            for (Object object : objects) {
                System.out.println(object);
            }
        }
    }
}
```

参考：
https://www.cnblogs.com/strongmore/p/14219180.html

原文出处：http://malaoshi.top/show_1GWBgo5e3Wj.html