@value注解和@ConfigurationProperties注解
@value读取默认配置
yml文件内容如下（装了STS插件以后即可直接使用，改后缀就行了）
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user: username: xiongda sex: man age: 20 school: name: xtu location: hunan |
备注：一定要注意之间要留空格，发现颜色变绿色了才是正确的格式，这个坑我刚踩
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package com.example.demo.service.impl; import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Service; import com.example.demo.service.ReadConfigService; @Service public class ReadConfigServiceImpl implements ReadConfigService { @Value (value= "${user.username}" ) private String username;
@Value (value= "${user.sex}" ) private String sex;
@Value (value= "${user.age}" ) private String age;
@Value (value= "${school.name}" ) private String name;
@Value (value= "${school.location}" ) private String location;
@Override public String getUserMessage() { return "user =" +username+ " sex =" +sex+ " age=" +age; }
@Override public String getAuthorMessage() { return "schoolname=" +name+ "location=" +location; } } |
@ConfigurationProperties读取默认配置
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package com.example.demo.config; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.stereotype.Component; @Component @ConfigurationProperties (prefix= "user" ) public class HelloConfig { private String username; private String sex; private String age; public String getUsername() { return username; }
public void setUsername(String username) { this .username = username; }
public String getSex() { return sex; }
public void setSex(String sex) { this .sex = sex; }
public String getAge() { return age; }
public void setAge(String age) { this .age = age; } } |
调用的controller层
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package com.example.demo.web; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.example.demo.config.HelloConfig; import com.example.demo.service.ReadConfigService;
@RestController @RequestMapping ( "hello" ) public class HelloController {
@Autowired ReadConfigService readConfigService;
@Autowired HelloConfig helloConfig;
@RequestMapping ( "/user" ) public String say() { return "username " +helloConfig.getUsername()+ " sex " +helloConfig.getSex()+ " age " +helloConfig.getAge(); }
@RequestMapping ( "/school" ) public String school() { return readConfigService.getAuthorMessage(); } } |
@ConfigurationProperties和@Value使用上的一点区别
@ConfigurationProperties和@Value的一个共同点就是从配置文件中读取配置项。
发现有一点区别，我项目配置中并没有配置hello.msg ，当使用第一段代码时，启动后读取到msg为null，而第二段代码则会抛出异常。
第二段代码有个好处，就是防止我们配置项遗漏，当遗漏时，启动程序肯定出错，这样避免了一些因为遗漏配置项导致的BUG.
第一段代码
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import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties ( "hello" ) public class HelloProperties { private String msg; public String getMsg() { return msg; } public void setMsg(String msg) { this .msg = msg; } } |
第二段代码
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import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; @Component public class Hello2Properties { @Value ( "${hello.msg}" ) private String msg; public String getMsg() { return msg; } public void setMsg(String msg) { this .msg = msg; } } |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
原文链接：https://blog.csdn.net/qq_29914229/article/details/81906406
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