在springmvc或其他ssh框架中如果我们要实现一个配置参数的加载,需要使用代码实现读取properties文件等操作,或者需要使用其他属性@value(name="username")等配置操作。但是在springboot中就比较简单操作:
1)自定义配置参数绑定:通过使用@ConfigurationProperties和@Component注解自定义参数配置类,之后程序启动时将自动加载application.properties配置文件中的对应的配置项;
2)第三方组件类的配置参数绑定:需要在springboot启动类内部把该参数配置类注册为一个Bean,同时注解@ConfigurationProperties就可以实现第三方组件配置参数加载;
3)配置参数绑定启动参数:无论是上边1)还是2)参数配置除了可以在application.properties中配置外,还可以绑定启动参数。
1)自定义配置参数绑定:
a)创建自定义配置参数类:
在app下新建包config,在app.config包下创建一个MySQLConfig.java:
package app.config; import lombok.Getter; import lombok.Setter; import lombok.ToString; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.stereotype.Component; @ConfigurationProperties(prefix = "db") @Component @Getter @Setter @ToString public class MySQLConfig { private String username; private String password; private String url; private String driverClassName; }
备注:上边注解@[email protected]@ToString的依赖包是lombok,需要在pom.xml添加配置:
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency>
c)在src/resources/application.properties中添加配置:
db.username="root" db.password="123456" db.url="jdbc:mysql:///mytestdb" db.driverClassName="com.mysql.jdbc.Driver"
备注:这里边的不区分大小写:db.driverClassName
可以写成:db.driverclassname=xx
可以写成:db.driver_class_name=xx
也可以写成db_driver-class_Name=xx
d)将app.config包注解为启动入口监控的组件包:
package app; import org.springframework.boot.Banner; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.boot.builder.SpringApplicationBuilder; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.ComponentScans; import java.util.Arrays; @ComponentScans({@ComponentScan("com.dx.controller"), @ComponentScan("app.config")}) @EnableAutoConfiguration public class App { public static void main(String[] args) { System.out.println(Arrays.toString(args)); // 启动方式一: SpringApplication.run(App.class, args); // 启动方式二: // SpringApplication springApplication = new SpringApplication(App.class); // springApplication.setBannerMode(Banner.Mode.OFF); // springApplication.run(args); // 启动方式三: // new SpringApplicationBuilder(App.class) // .bannerMode(Banner.Mode.OFF) // .build() // .run(args); } }
e)新建测试接口类DataSourceTestController.java:
package com.dx.controller; import app.config.MySQLConfig; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; @Controller public class DataSourceTestController { @Autowired private MySQLConfig mySQLConfig; @RequestMapping("/dataSource") @ResponseBody public String dataSource() { System.out.println(mySQLConfig); return "dataSource"; } }
f)运行app.App.java,在浏览器中访问http://localhost:8888/dataSource回车,查看打印信息:
MySQLConfig(username="root", password="123456", url="jdbc:mysql:///mytestdb", driverClassName="com.mysql.jdbc.Driver")
2)第三方组件类的配置参数绑定:
a)假设上边自定义参数配置类app.config.MySQLConfig.java为一个第三方参数配置类:
package app.config; import lombok.Getter; import lombok.Setter; import lombok.ToString; @[email protected]@ToString public class MySQLConfig { private String username; private String password; private String url; private String driverClassName; }
b)在入口类中注册三方组件中参数配置类:
package app; import app.config.MySQLConfig; import org.springframework.boot.Banner; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.EnableAutoConfiguration; import org.springframework.boot.builder.SpringApplicationBuilder; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.ComponentScans; import java.util.Arrays; @ComponentScans({@ComponentScan("com.dx.controller")}) @EnableAutoConfiguration public class App { @Bean @ConfigurationProperties(prefix = "db") public MySQLConfig mySQLConfig() { return new MySQLConfig(); } public static void main(String[] args) { System.out.println(Arrays.toString(args)); // 启动方式一: SpringApplication.run(App.class, args); // 启动方式二: // SpringApplication springApplication = new SpringApplication(App.class); // springApplication.setBannerMode(Banner.Mode.OFF); // springApplication.run(args); // 启动方式三: // new SpringApplicationBuilder(App.class) // .bannerMode(Banner.Mode.OFF) // .build() // .run(args); } }
c)测试:运行app.config.App.java,在浏览器中访问http://localhost:8888/dataSource,回车。查看打印信息:
MySQLConfig(username="root", password="123456", url="jdbc:mysql:///mytestdb", driverClassName="com.mysql.jdbc.Driver")
3)配置参数绑定启动参数:
打包项目为jar包,进入jar包生成目录执行:
java -jar jar包名称 --db.username=root --db.password=12345678 --db.url=jdbc:mysql:///mydb --db.driver=com.mysql.jdbc.Driver
执行后,访问地址http://localhost:8888/dataSource回车。此时,查看打印信息如下:
E:\Work\springboot\springboothelloword\target>java -jar springboot-helloword-1.0-SNAPSHOT.jar --db.username=root --db.password=12345678 --db.url=jdbc:mysql:///mydb --db.driver=com.mysql.jdbc.Driver [--db.username=root, --db.password=12345678, --db.url=jdbc:mysql:///mydb, --db.driver=com.mysql.jdbc.Driver] _ooOoo_ o8888888o 88" . "88 (| -_- |) O\ = /O ____/`---‘\____ .‘ \\| |// `. / \\||| : |||// \ / _||||| -:- |||||- | | \\\ - /// | | | \_| ‘‘\---/‘‘ | | \ .-\__ `-` ___/-. / ___`. .‘ /--.--\ `. . __ ."" ‘< `.___\_<|>_/___.‘ >‘"". | | : `- \`.;`\ _ /`;.`/ - ` : | | \ \ `-. \_ __\ /__ _/ .-` / / ======`-.____`-.___\_____/___.-`____.-‘====== `=---=‘ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 佛祖保佑 永无BUG 2018-04-07 22:38:39.210 INFO 10288 --- [ main] app.App : Started App in 4.387 seconds (JVM running for 5.763) 2018-04-07 22:38:46.759 INFO 10288 --- [nio-8888-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring FrameworkServlet ‘dispatcherServlet‘ 2018-04-07 22:38:46.761 INFO 10288 --- [nio-8888-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet‘: initialization started 2018-04-07 22:38:46.805 INFO 10288 --- [nio-8888-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet ‘dispatcherServlet‘: initialization completed in 44 ms MySQLConfig(username=root, password=12345678, url=jdbc:mysql:///mydb, driverClassName="com.mysql.jdbc.Driver")
原文地址:https://www.cnblogs.com/yy3b2007com/p/8735367.html