springboot给类进行赋初值的四种方式

1. 使用@Value和@ConfigurationProperties

这里不加赘述了，前面我也发过，这里就放个链接吧
@Value获取值和@ConfigurationProperties获取值用法及比较（springboot）

2. 使用@PropertySource

创建Person.java

package com.example.springbootdaily2.model;import org.springframework.format.annotation.DateTimeFormat;import java.util.Date;
import java.util.List;
import java.util.Map;@Component
@PropertySource(value = "classpath:person.properties")
// 这个是前缀的意思
@ConfigurationProperties(prefix = "person2")
public class PersonX {private String name;private Character sex;@DateTimeFormat(pattern = "YYYY-MM-SS")private Date birthday;private Integer age;private String address;private Map<String, Integer> maps;private List<String> lists;private Dog dog;public String getName() {return name;}public void setName(String name) {this.name = name;}public Character getSex() {return sex;}public void setSex(Character sex) {this.sex = sex;}public Date getBirthday() {return birthday;}public void setBirthday(Date birthday) {this.birthday = birthday;}public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}public Dog getDog() {return dog;}public void setDog(Dog dog) {this.dog = dog;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Map<String, Integer> getMaps() {return maps;}public void setMaps(Map<String, Integer> maps) {this.maps = maps;}public List<String> getLists() {return lists;}public void setLists(List<String> lists) {this.lists = lists;}@Overridepublic String toString() {return "Person{" +"name='" + name + '\'' +", sex=" + sex +", birthday=" + birthday +", age=" + age +", address='" + address + '\'' +", maps=" + maps +", lists=" + lists +", dog=" + dog +'}';}
}

创建person.properties

person2.name="李四"
person2.sex=男
person2.birthday=2022-02-07
person2.age=18
person2.maps.keys1=16
person2.maps.keys2=16
person2.lists=[12,24,57]
person2.address="保定廉耻"
person2.dog.name=${random.value}

写一个测试类

package com.example.springbootdaily;
import com.example.springbootdaily.model.Dog;
import com.example.springbootdaily.model.Person;
import com.example.springbootdaily.model.Person2;
import com.example.springbootdaily.model.PersonX;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringTest {@AutowiredPersonX personX;@Testpublic void print4(){System.out.println(personX);}
}

输出结果：

Person{name='"岳轩子"', sex=M, 
birthday=Sun Dec 26 00:00:00 CST 2021, age=18, 
address='"保定武汉"', maps={keys2=16, keys1=16}, lists=[[12, 24, 57]], 
dog=Dog{name='cdab390f55c9f8a6bbb420cd15607add'}}

注：如果显示乱码，设置文件编码为utf-8
在这里插入图片描述

3. 使用@ImportResource

Student类

package com.example.springbootdaily.model;public class Student {private String name;private Integer age;public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}@Overridepublic String toString() {return "Student{" +"name='" + name + '\'' +", age=" + age +'}';}
}

创建beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="student" class="com.example.springbootdaily.model.Student"><property name="name" value="李四"/><property name="age" value="18"/></bean>
</beans>

在主类中引入

package com.example.springbootdaily;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ImportResource;@SpringBootApplication
@ImportResource(locations = "classpath:beans.xml")
public class SpringbootDailyApplication {public static void main(String[] args) {SpringApplication.run(SpringbootDailyApplication.class, args);}}

测试

package com.example.springbootdaily;import com.example.springbootdaily.model.*;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringTest {@AutowiredStudent student;@Testpublic void print5(){System.out.println(student);}
}