SpringBoot 如何从配置文件读取值到对象中

SpringBoot 如何从配置文件读取值到对象中

目录一、实现方式@ConfigurationProperties 注解@Valid注解二、两者区别三、代码演示四、@PropertySource 读取指定配置文件五、@ImportResource:导入Spring配置文件六、思维导图

一、实现方式

@ConfigurationProperties 注解

（最好加上前缀prefix=“person”,标明是和配置文件中哪个开头的属性匹配）

推荐使用用在类上，从配置文件读取属性值，放到对象里面，复杂的结构也适用例如map,list，对象。支持校验:@Validated

@Valid注解

用在属性上，需要每个属性逐个绑定通过@value注解获取配置文件的值,不适合做复杂类型（map,list ,对象）值得获取不支持@Validated

二、两者区别

三、代码演示

使用@ConfigurationProperties注解

package com.wx.springboot20190911.demo.model;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.stereotype.Component;

import org.springframework.validation.annotation.Validated;

import javax.validation.constraints.Email;

import java.util.Date;

import java.util.List;

import java.util.Map;

/**

* 1.ConfigurationProperties注解 从配置文件读取属性值，放到对象里面

* 2.通过@value注解获取配置文件的值

*/

@Component//perosn 需要纳入spring ioc 容器里

@ConfigurationProperties(prefix = "person")//使用前缀标明具体的属性

@Validated

public class Person {

@Email

String email;

String hello;

String name;

int age;

boolean boss;

Date birth;

Map maps;

List list;

Dog dog;

@Override

public String toString() {

return "Person{" +

"email='" + email + '\'' +

", hello='" + hello + '\'' +

", name='" + name + '\'' +

", age=" + age +

", boss=" + boss +

", birth=" + birth +

", maps=" + maps +

", list=" + list +

", dog=" + dog +

'}';

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

public String getHello() {

return hello;

}

public void setHello(String hello) {

this.hello = hello;

}

public Dog getDog() {

return dog;

}

public void setDog(Dog dog) {

this.dog = dog;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public boolean isBoss() {

return boss;

}

public void setBoss(boolean boss) {

this.boss = boss;

}

public Date getBirth() {

return birth;

}

public void setBirth(Date birth) {

this.birth = birth;

}

public Map getMaps() {

return maps;

}

public void setMaps(Map maps) {

this.maps = maps;

}

public List getList() {

return list;

}

public void setList(List list) {

this.list = list;

}

}

package com.wx.springboot20190911.demo.model;

public class Dog {

String name;

String color;

int age;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getColor() {

return color;

}

public void setColor(String color) {

this.color = color;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

@Override

public String toString() {

return "Dog{" +

"name='" + name + '\'' +

", color='" + color + '\'' +

", age=" + age +

'}';

}

}

使用@Value注解

package com.wx.springboot20190911.demo.model;

import org.springframework.beans.factory.annotation.Value;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.stereotype.Component;

import org.springframework.validation.annotation.Validated;

import javax.validation.Valid;

import javax.validation.constraints.Email;

import java.util.Date;

import java.util.List;

import java.util.Map;

/**

* 1.ConfigurationProperties注解 从配置文件读取属性值，放到对象里面，推荐使用，复杂的结构也适用例如map,list对象,

* 支持 校验@Validated

* 2.通过@value注解获取配置文件的值,不适合做复杂类型值得获取,不支持@Validated，支持

*/

@Component//perosn 需要纳入spring ioc 容器里

//@ConfigurationProperties(prefix = "person")

@Validated

public class Person1 {

@Email

@Value("${person1.email}")

String email;

@Value("${person1.hello}")

String hello;

@Value("${person1.name}")

String name;

@Value("#{12*3}")//支持计算

int age;

@Value("${person1.boss}")

boolean boss;

@Value("${person1.birth}")

Date birth;

Map maps;

List list;

Dog dog;

public String getHello() {

return hello;

}

public void setHello(String hello) {

this.hello = hello;

}

public Dog getDog() {

return dog;

}

public void setDog(Dog dog) {

tQlNwzbnEtWhis.dog = dog;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public boolean isBoss() {

return boss;

}

public void setBoss(boolean boss) {

this.boss = boss;

}

public Date getBirth() {

return birth;

}

public void setBirth(Date birth) {

this.birth = birth;

}

public Map getMaps() {

return maps;

}

public void setMaps(Map maps) {

this.maps = maps;

}

public List getList() {

return list;

}

public void setList(List list) {

this.list = list;

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

@Override

public String toString() {

return "Person1{" +

"email='" + email + '\'' +

", hello='" + hello + '\'' +

", name='" + name + '\'' +

", age=" + age +

", boss=" + boss +

", birth=" + birth +

", maps=" + maps +

", list=" + list +

", dog=" + dog +

'}';

}

}

配置类（application.properties）代码

person.hello=luck

person.name=吴

#乱码的话 就setting设置下file encoding

person.list=ww,xx,rr

person.maps.k1=v1

person.maps.k2=v2

person.dog.name=cat

person.dog.color=red

person.dog.age=1

person.age=12

person.birth=2019/01/11

person.boss=false

person.email=www@qq.com

person1.hello=luck

person1.name=吴

#乱码的话 就setting设置下file encoding

person1.list=ww,xx,rr

person1.age=12

person1.birth=2019/01/11

person1.boss=false

person1.email=www

配置类(application.yml)代码:这种方式更加结构化

person:

name: 霞

age: 16

boss : false

birth: 2012/09/12

maps: {k1: v1,k2: v2}

list: [dog,cat ,house,rabbits]

dog:

name: ${person.hello}

age: ${random.int(10)}

color: white

hello: yula

打印结果：使用第一种方式时，如果email不是"www@qq.com"这种格式，是不能运行成功的，但是使用@Value 不会校验，如下面是"www",一样能运行成功

Person{email='www@qq.com', hello='luck', name='吴', age=12, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps={k1=v1, k2=v2}, list=[ww, xx, rr], dog=Dog{name='cat', color='red', age=1}}

Person1{email='www', hello='luck', name='吴', age=36, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps=null, list=null, dog=null}

四、@PropertySource 读取指定配置文件

package com.wx.springboot20190911.demo.model;

import org.springframework.boot.context.properties.ConfigurationProperties;

import org.springframework.context.annotation.PropertySource;

import org.springframework.stereotype.Component;

import org.springframework.validation.annotation.Validated;

import javax.validation.constraints.Email;

import java.util.Date;

import java.util.List;

import java.util.Map;

/**

* 1.ConfigurationProperties注解 从配置文件读取属性值，放到对象里面

* 2.通过@value注解获取配置文件的值

*/

@PropertySource(value={"classpath:person.properties"})//指定读取person.properties配置文件

@Component//perosn 需要纳入spring ioc 容器里

@ConfigurationProperties(prefix = "person")//使用前缀标明具体的属性

@Validated

public class Person2 {

@Email

String email;

String hello;

String name;

int age;

boolean boss;

Date birth;

Map maps;

List list;

Dog dog;

@Override

public String toString() {

return "Person{" +

"email='" + email + '\'' +

", hello='" + hello + '\'' +

", name='" + name + '\'' +

", age=" + age +

", boss=" + boss +

", birth=" + birth +

", maps=" + maps +

", list=" + list +

", dog=" + dog +

'}';

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

public String getHello() {

return hello;

}

public void setHello(String hello) {

this.hello = hello;

}

public Dog getDog() {

return dog;

}

public void setDog(Dog dog) {

this.dog = dog;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public boolean isBoss() {

return boss;

}

public void setBoss(boolean boss) {

this.boss = boss;

}

public Date getBirth() {

return birth;

}

public void setBirth(Date birth) {

this.birth = birth;

}

public Map getMaps() {

return maps;

}

public void setMaps(Map maps) {

this.maps = maps;

}

public List getList() {

return list;

}

public void setList(List list) {

this.list = list;

}

}

这里虽然指定了读取person.properties配置文件，但是由于prefix=“person”,导致还是读取了application.properties配置文件，因为application.properties权限最高，要想读取person.properties配置文件，就得改前缀名，例如改成prefix=“person2” person.properties配置文件的内容如下：

没改前缀名的结果演示：

Person{email='www@qq.com', hello='luck', name='吴', age=12, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps={k1=v1, k2=v2}, list=[ww, xx, rr], dog=Dog{name='cat', color='red', age=1}}

Person1{email='www', hello='luck', name='吴', age=36, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps=null, list=null, dog=null}

Person{email='www@qq.com', hello='luck', name='吴', age=12, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps={k1=v1, k2=v2}, list=[ww, xx, rr], dog=Dog{name='cat', color='red', age=1}}

改前缀名的代码演示：

改了前缀名的结果演示：这时候读取的就是指定的配置文件的值

Person{email='www@qq.com', hello='luck', name='吴', age=12, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps={k1=v1, k2=v2}, list=[ww, xx, rr], dog=Dog{name='cat', color='red', age=1}}

Person1{email='www', hello='luck', name='吴', age=36, boss=false, birth=Fri Jan 11 00:00:00 CST 2019, maps=null, list=null, dog=null}

Person{email='12345@qq.com', hello='springboot', name='指定读取配置文件', age=12, boss=false, birth=Wed Sep 11 00:00:00 CST 2019, maps={k2=v2, k1=v1}, list=[@Value, @PropertySource], dog=Dog{name='cat', color='red', age=1}}

注：只能读取 .properties 文件，无法读取 .yml 文件

五、@ImportResource:导入Spring配置文件

让配置文件里面的内容生效

Springboot 里没有Spring 的配置文件，我们自己编写的配置文件，也不能自动识别；

想让Spring的配置文件生效，加载进来，需使用该注解

写一个Person3 类，如图所示：

自定义一个Spring配置文件，如图所示：

在启动类上注解

测试：自定义的这个配置文件是否生效

演示结果：生效了

2019-09-11 22:15:12.247 INFO 7824 --- [ main] c.w.s.demo.DemoApplicationTests : Started DemoApplicationTests in 8.558 seconds (JVM running for 10.882)

Person{email='null', hello='null', name='null', age=0, boss=false, birth=null, maps=null, list=null, dog=null}

六、思维导图

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