7

假设我有一个文件defaults.yaml

pool:
  idleConnectionTestPeriodSeconds: 30
  idleMaxAgeInMinutes: 60
  partitionCount: 4
  acquireIncrement: 5
  username: dev
  password: dev_password

和另一个文件,production.yaml

pool:
  username: prod
  password: prod_password

在运行时,我如何读取这两个文件并将它们合并为一个,以便应用程序“看到”以下内容?

pool:
  idleConnectionTestPeriodSeconds: 30
  idleMaxAgeInMinutes: 60
  partitionCount: 4
  acquireIncrement: 5
  username: prod
  password: prod_password

比如说 SnakeYAML,这可能吗?还有其他工具吗?

我知道一种选择是将多个文件作为 Maps 读取,然后自己合并它们,将合并呈现为一个临时文件,然后读取它,但这是一个重量级的解决方案。现有工具可以做到这一点吗?

4

1 回答 1

7

您可以使用 Jackson,关键是使用ObjectMapper.readerForUpdating()并使用@JsonMerge注释该字段(或下一个对象中的所有缺失字段将覆盖旧字段):

马文:

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.9</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.dataformat</groupId>
        <artifactId>jackson-dataformat-yaml</artifactId>
        <version>2.9.9</version>
    </dependency>

代码:

public class TestJackson {
    public static void main(String[] args) throws IOException {
        ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
        MyConfig myConfig = new MyConfig();
        ObjectReader objectReader = mapper.readerForUpdating(myConfig);
        objectReader.readValue(new File("misc/a.yaml"));
        objectReader.readValue(new File("misc/b.yaml"));
        System.out.println(myConfig);
    }

    @Data
    public static class MyConfig {
        @JsonMerge
        private Pool pool;
    }

    @Data
    public static class Pool {
        private Integer idleConnectionTestPeriodSeconds;
        private Integer idleMaxAgeInMinutes;
        private Integer partitionCount;
        private Integer acquireIncrement;
        private String username;
        private String password;
    }
}
于 2019-07-24T15:46:58.720 回答