本文目录导读：
我来详细讲解Java中YAML配置文件的编写方法,包含多个实际案例。
基础YAML配置案例
1 添加依赖
Maven依赖
<!-- Spring Boot项目已内置 -->
<!-- 单独使用需添加 -->
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-yaml</artifactId>
<version>2.15.2</version>
</dependency>
<dependency>
<groupId>org.yaml</groupId>
<artifactId>snakeyaml</artifactId>
<version>2.2</version>
</dependency>
2 基础配置文件（application.yml）
# 服务器配置
server:
port: 8080
servlet:
context-path: /api
# 数据库配置
database:
url: jdbc:mysql://localhost:3306/myapp
username: root
password: ${DB_PASSWORD:password123} # 支持环境变量
driver-class-name: com.mysql.cj.jdbc.Driver
pool:
initial-size: 5
max-active: 20
min-idle: 5
# 应用配置
app:
name: "My Application"
version: 1.0.0
debug: true
languages:
- zh-CN
- en-US
- ja-JP
使用@ConfigurationProperties注解
1 创建配置类
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties(prefix = "app")
public class AppConfig {
private String name;
private String version;
private boolean debug;
private List<String> languages;
private DatabaseConfig database;
// 嵌套配置类
public static class DatabaseConfig {
private String url;
private String username;
private String password;
private String driverClassName;
private PoolConfig pool;
// getters and setters
// ...
}
public static class PoolConfig {
private int initialSize;
private int maxActive;
private int minIdle;
// getters and setters
// ...
}
// getters and setters
}
2 启用配置属性
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
@SpringBootApplication
@EnableConfigurationProperties({AppConfig.class})
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
复杂YAML配置案例
1 多环境配置
application-dev.yml
server:
port: 8081
database:
url: jdbc:mysql://localhost:3306/dev_db
username: dev_user
password: dev_pass
logging:
level:
root: DEBUG
com.example: TRACE
application-prod.yml
server:
port: 8080
database:
url: jdbc:mysql://production:3306/prod_db
username: prod_user
password: ${PROD_DB_PASSWORD}
logging:
level:
root: WARN
com.example: INFO
2 集合和复杂结构
# 复杂配置案例
feature-flags:
- name: new-payment-system
enabled: true
rollout-percentage: 50
description: "新支付系统"
metadata:
team: payment-team
jira-ticket: PAY-1234
created-date: 2024-01-15
- name: dark-mode
enabled: ${DARK_MODE_ENABLED:false}
rollout-percentage: 100
description: "暗黑模式"
metadata:
team: ui-team
jira-ticket: UI-5678
created-date: 2024-02-01
# 映射配置
cache:
providers:
redis:
host: ${REDIS_HOST:localhost}
port: ${REDIS_PORT:6379}
timeout: 5000
pool:
max-total: 16
max-idle: 8
local:
max-size: 1000
ttl: 3600
读取YAML配置的多种方式
1 使用@Value注解
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
@Service
public class ConfigService {
@Value("${app.name}")
private String appName;
@Value("${database.url}")
private String databaseUrl;
@Value("${server.port:8080}") // 设置默认值
private int port;
@Value("#{'${app.languages}'.split(',')}")
private List<String> languages;
public void printConfig() {
System.out.println("App Name: " + appName);
System.out.println("Database URL: " + databaseUrl);
System.out.println("Port: " + port);
}
}
2 使用SnakeYAML直接解析
import org.yaml.snakeyaml.Yaml;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Map;
public class YamlParser {
public static Map<String, Object> parseYaml(String filePath) {
Yaml yaml = new Yaml();
try (InputStream inputStream = new FileInputStream(filePath)) {
return yaml.load(inputStream);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public static <T> T parseYaml(String filePath, Class<T> type) {
Yaml yaml = new Yaml();
try (InputStream inputStream = new FileInputStream(filePath)) {
return yaml.loadAs(inputStream, type);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
实用配置案例
1 线程池配置
thread-pool: core-size: 10 max-size: 50 keep-alive-seconds: 60 queue-capacity: 100 thread-name-prefix: "async-" rejected-execution-handler: "CallerRunsPolicy"
@Component
@ConfigurationProperties(prefix = "thread-pool")
public class ThreadPoolConfig {
private int coreSize;
private int maxSize;
private int keepAliveSeconds;
private int queueCapacity;
private String threadNamePrefix;
private String rejectedExecutionHandler;
public ExecutorService createExecutor() {
ThreadPoolExecutor executor = new ThreadPoolExecutor(
coreSize,
maxSize,
keepAliveSeconds,
TimeUnit.SECONDS,
new LinkedBlockingQueue<>(queueCapacity),
new ThreadFactoryBuilder()
.setNameFormat(threadNamePrefix + "%d")
.build(),
new ThreadPoolExecutor.CallerRunsPolicy()
);
return executor;
}
// getters and setters
}
2 邮件配置
mail:
host: smtp.gmail.com
port: 587
username: ${MAIL_USERNAME}
password: ${MAIL_PASSWORD}
properties:
mail.smtp.auth: true
mail.smtp.starttls.enable: true
mail.smtp.connectiontimeout: 5000
mail.smtp.timeout: 5000
mail.smtp.writetimeout: 5000
default-encoding: UTF-8
templates:
welcome: classpath:/templates/welcome.html
reset-password: classpath:/templates/reset-password.html
notification: classpath:/templates/notification.html
配置验证
import javax.validation.constraints.*;
import org.springframework.validation.annotation.Validated;
@Component
@ConfigurationProperties(prefix = "app")
@Validated
public class ValidatedConfig {
@NotBlank(message = "应用名称不能为空")
private String name;
@NotNull
@Pattern(regexp = "^\\d+\\.\\d+\\.\\d+$", message = "版本号格式错误")
private String version;
@Min(value = 1024, message = "端口号最小为1024")
@Max(value = 65535, message = "端口号最大为65535")
private int port;
@Email(message = "邮箱格式不正确")
private String contactEmail;
@NotEmpty(message = "语言列表不能为空")
private List<String> languages;
// getters and setters
}
动态刷新配置
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;
@Component
@RefreshScope
@ConfigurationProperties(prefix = "dynamic")
public class DynamicConfig {
private String featureFlag;
private int maxRetries;
private Map<String, String> mappings;
// getters and setters
}
最佳实践建议
- 使用降级默认值：为关键配置提供默认值
- 环境变量覆盖：支持通过环境变量覆盖配置
- 配置分组：按功能模块组织配置
- 敏感信息加密：使用加密工具处理密码等敏感信息
- 配置校验：使用@Validated进行验证
- 文档注释：在YAML中添加注释说明
这些案例覆盖了Java中YAML配置的主要使用场景,可以根据实际需求选择合适的方式。
