1. 配置文件概述
Spring Boot支持多种配置方式,提供了灵活的配置管理机制。配置文件是Spring Boot应用的核心组成部分,用于管理应用的各种参数和设置。
1.1 配置文件类型
Spring Boot支持以下配置文件格式:
- Properties文件:
application.properties - YAML文件:
application.yml或application.yaml - JSON文件:
application.json - 环境变量
- 命令行参数
1.2 配置文件优先级
Spring Boot按以下顺序加载配置(后面的会覆盖前面的):
- 命令行参数
- 系统环境变量
- JNDI属性
- 系统属性
- 配置文件(按优先级顺序)
2. Properties配置
2.1 基本语法
# 服务器配置
server.port=8080
server.servlet.context-path=/api
server.servlet.session.timeout=30m
# 数据库配置
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# JPA配置
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
# 日志配置
logging.level.root=INFO
logging.level.com.example.demo=DEBUG
logging.file.name=logs/application.log
2.2 多环境配置
application-dev.properties
# 开发环境配置
server.port=8080
spring.datasource.url=jdbc:h2:mem:devdb
spring.jpa.hibernate.ddl-auto=create-drop
logging.level.com.example.demo=DEBUG
application-test.properties
# 测试环境配置
server.port=8081
spring.datasource.url=jdbc:h2:mem:testdb
spring.jpa.hibernate.ddl-auto=create
logging.level.com.example.demo=INFO
application-prod.properties
# 生产环境配置
server.port=8080
spring.datasource.url=jdbc:mysql://prod-server:3306/proddb
spring.datasource.username=${DB_USERNAME}
spring.datasource.password=${DB_PASSWORD}
spring.jpa.hibernate.ddl-auto=validate
logging.level.root=WARN
3. YAML配置
3.1 基本语法
server:
port: 8080
servlet:
context-path: /api
session:
timeout: 30m
spring:
datasource:
url: jdbc:mysql://localhost:3306/mydb
username: root
password: 123456
driver-class-name: com.mysql.cj.jdbc.Driver
jpa:
hibernate:
ddl-auto: update
show-sql: true
properties:
hibernate:
dialect: org.hibernate.dialect.MySQL8Dialect
logging:
level:
root: INFO
com.example.demo: DEBUG
file:
name: logs/application.log
3.2 多环境YAML配置
application.yml
spring:
profiles:
active: dev
---
spring:
profiles: dev
server:
port: 8080
logging:
level:
com.example.demo: DEBUG
---
spring:
profiles: test
server:
port: 8081
logging:
level:
com.example.demo: INFO
---
spring:
profiles: prod
server:
port: 8080
logging:
level:
root: WARN
4. 配置属性绑定
4.1 @ConfigurationProperties
创建配置属性类:
package com.example.demo.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.util.List;
import java.util.Map;
@Component
@ConfigurationProperties(prefix = "app")
public class AppProperties {
private String name;
private String version;
private Database database;
private List<String> features;
private Map<String, String> settings;
// 嵌套配置类
public static class Database {
private String host;
private int port;
private String username;
private String password;
// getter和setter方法
public String getHost() { return host; }
public void setHost(String host) { this.host = host; }
public int getPort() { return port; }
public void setPort(int port) { this.port = port; }
public String getUsername() { return username; }
public void setUsername(String username) { this.username = username; }
public String getPassword() { return password; }
public void setPassword(String password) { this.password = password; }
}
// getter和setter方法
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public String getVersion() { return version; }
public void setVersion(String version) { this.version = version; }
public Database getDatabase() { return database; }
public void setDatabase(Database database) { this.database = database; }
public List<String> getFeatures() { return features; }
public void setFeatures(List<String> features) { this.features = features; }
public Map<String, String> getSettings() { return settings; }
public void setSettings(Map<String, String> settings) { this.settings = settings; }
}
对应的配置文件:
app:
name: "My Application"
version: "1.0.0"
database:
host: "localhost"
port: 3306
username: "root"
password: "123456"
features:
- "user-management"
- "file-upload"
- "email-notification"
settings:
max-file-size: "10MB"
session-timeout: "30m"
4.2 使用配置属性
package com.example.demo.service;
import com.example.demo.config.AppProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class AppService {
@Autowired
private AppProperties appProperties;
public String getAppInfo() {
return String.format("应用名称:%s,版本:%s",
appProperties.getName(),
appProperties.getVersion());
}
public String getDatabaseUrl() {
AppProperties.Database db = appProperties.getDatabase();
return String.format("jdbc:mysql://%s:%d", db.getHost(), db.getPort());
}
}
5. 环境变量配置
5.1 环境变量设置
# Windows
set SPRING_PROFILES_ACTIVE=prod
set DB_USERNAME=root
set DB_PASSWORD=123456
# Linux/Mac
export SPRING_PROFILES_ACTIVE=prod
export DB_USERNAME=root
export DB_PASSWORD=123456
5.2 在配置文件中使用环境变量
# 使用环境变量
spring.datasource.username=${DB_USERNAME:defaultuser}
spring.datasource.password=${DB_PASSWORD:defaultpass}
spring.profiles.active=${SPRING_PROFILES_ACTIVE:dev}
6. 命令行参数配置
6.1 启动时传递参数
# 设置端口
java -jar app.jar --server.port=9090
# 设置配置文件
java -jar app.jar --spring.profiles.active=prod
# 设置数据库配置
java -jar app.jar --spring.datasource.url=jdbc:mysql://localhost:3306/mydb
6.2 程序化设置参数
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
// 添加命令行参数
String[] newArgs = new String[args.length + 2];
System.arraycopy(args, 0, newArgs, 0, args.length);
newArgs[args.length] = "--server.port=8080";
newArgs[args.length + 1] = "--spring.profiles.active=dev";
SpringApplication.run(DemoApplication.class, newArgs);
}
}
7. 配置验证
7.1 使用@Validated验证
package com.example.demo.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
@Component
@ConfigurationProperties(prefix = "app")
@Validated
public class ValidatedAppProperties {
@NotBlank(message = "应用名称不能为空")
private String name;
@NotBlank(message = "版本号不能为空")
private String version;
@Min(value = 1, message = "端口号必须大于0")
@Max(value = 65535, message = "端口号不能超过65535")
private int port;
@NotNull(message = "数据库配置不能为空")
private Database database;
public static class Database {
@NotBlank(message = "数据库主机不能为空")
private String host;
@Min(value = 1, message = "数据库端口必须大于0")
@Max(value = 65535, message = "数据库端口不能超过65535")
private int port;
// getter和setter方法
public String getHost() { return host; }
public void setHost(String host) { this.host = host; }
public int getPort() { return port; }
public void setPort(int port) { this.port = port; }
}
// getter和setter方法
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public String getVersion() { return version; }
public void setVersion(String version) { this.version = version; }
public int getPort() { return port; }
public void setPort(int port) { this.port = port; }
public Database getDatabase() { return database; }
public void setDatabase(Database database) { this.database = database; }
}
7.2 自定义验证器
package com.example.demo.validator;
import javax.validation.Constraint;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.Payload;
import java.lang.annotation.*;
import java.util.regex.Pattern;
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = Email.EmailValidator.class)
public @interface Email {
String message() default "邮箱格式不正确";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
class EmailValidator implements ConstraintValidator<Email, String> {
private static final Pattern EMAIL_PATTERN =
Pattern.compile("^[A-Za-z0-9+_.-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$");
@Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if (value == null || value.isEmpty()) {
return true; // 空值由@NotBlank处理
}
return EMAIL_PATTERN.matcher(value).matches();
}
}
}
8. 配置外部化
8.1 外部配置文件
# 指定外部配置文件位置
java -jar app.jar --spring.config.location=classpath:/application.yml,file:./config/
# 指定配置文件名称
java -jar app.jar --spring.config.name=myapp
8.2 配置中心集成
package com.example.demo.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties(prefix = "app")
@RefreshScope // 支持配置热刷新
public class RefreshableAppProperties {
private String name;
private String version;
// getter和setter方法
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public String getVersion() { return version; }
public void setVersion(String version) { this.version = version; }
}
9. 配置管理最佳实践
9.1 配置分层
config/
├── application.yml # 基础配置
├── application-dev.yml # 开发环境
├── application-test.yml # 测试环境
├── application-prod.yml # 生产环境
└── application-secret.yml # 敏感配置(不提交到版本控制)
9.2 敏感信息处理
# 使用占位符
spring:
datasource:
username: ${DB_USERNAME:defaultuser}
password: ${DB_PASSWORD:defaultpass}
url: ${DB_URL:jdbc:h2:mem:testdb}
9.3 配置文档化
package com.example.demo.config;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.Description;
@Component
@ConfigurationProperties(prefix = "app")
public class DocumentedAppProperties {
@Description("应用名称")
private String name;
@Description("应用版本")
private String version;
@Description("服务器端口")
private int port = 8080;
// getter和setter方法
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public String getVersion() { return version; }
public void setVersion(String version) { this.version = version; }
public int getPort() { return port; }
public void setPort(int port) { this.port = port; }
}
10. 配置调试
10.1 配置信息端点
# 启用配置信息端点
management:
endpoints:
web:
exposure:
include: configprops,env
endpoint:
configprops:
show-values: always
访问配置信息:
- 所有配置:
GET /actuator/env - 配置属性:
GET /actuator/configprops
10.2 配置调试工具
package com.example.demo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.Map;
@RestController
public class ConfigController {
@Autowired
private Environment environment;
@GetMapping("/config")
public Map<String, Object> getConfig() {
Map<String, Object> config = new HashMap<>();
config.put("activeProfiles", environment.getActiveProfiles());
config.put("defaultProfiles", environment.getDefaultProfiles());
config.put("serverPort", environment.getProperty("server.port"));
config.put("databaseUrl", environment.getProperty("spring.datasource.url"));
return config;
}
}
11. 总结
Spring Boot的配置系统提供了强大而灵活的配置管理能力:
- 多种配置格式:支持Properties、YAML、JSON等格式
- 环境分离:支持多环境配置管理
- 属性绑定:使用@ConfigurationProperties进行类型安全的配置绑定
- 配置验证:支持JSR-303验证注解
- 外部化配置:支持外部配置文件和配置中心
- 配置调试:提供配置信息查看和调试工具
通过合理使用这些配置特性,可以构建出易于维护和部署的Spring Boot应用。
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