Java操作与解析 YAML 文件教程

<dependency>
<groupId>org.yaml</groupId>
<artifactId>snakeyaml</artifactId>
<version>{latest_version}</version>
</dependency>

server:
host: localhost
port: 8080

database:
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost/testdb
username: root
password: secret

import org.yaml.snakeyaml.Yaml;
import java.io.InputStream;
import java.util.Map;

public class YamlParser {

public static void main(String[] args) throws Exception{
InputStream input = new FileInputStream("path/to/config.yml");

// 创建Yaml实例
Yaml yaml = new Yaml();

// 加载整个文档进入内存，并转换成Map类型以便进一步访问或修改内容
Map<String, Object> data = (Map<String, Object>) yaml.load(input);

System.out.println(data.get("server"));
// 输出：{host=localhost, port=8080}

@SuppressWarnings("unchecked")
Map<String, String> serverConfig = (Map<String, String>)data.get("server");

System.out.println(serverConfig.get("port"));
// 输出：8080

// 关闭流资源
input.close();
}
}

// 假设有一个已有的JavaBean类 Server 和 Database 类用于存储相关属性
Server server = ...; // 初始化服务器相关信息
Database database = ...; // 初始化数据库相关信息

HashMap<Object, Object> configData = new HashMap<>();
configData.put("server", server.getProperties());
configData.put("database", database.getProperties());

DumperOptions options = new DumperOptions();
options.setDefaultFlowStyle(DumperOptions.FlowStyle.BLOCK);

Yaml yaml = new Yaml(options);

String output = yaml.dump(configData);

FileOutputStream outputStream = new FileOutputStream(new File("output_config.yml"));

try {
outputStream.write(output.getBytes(StandardCharsets.UTF_8));
} finally {
if (outputStream != null)
outputStream.close();
}