Java教程
注解的使用之Autowired注解的使用
本文主要是介绍注解的使用之Autowired注解的使用，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！
引用类型的注入可以使用@Autowired
@Autowired：spring框架提供的注解，实现引用类型的赋值。
spring中通过注解给引用类型赋值，使用的是自动注入原理，支持byName，byType
@Autowired：默认使用的是byType自动注入
位置：1）在属性定义的上面，无需set方法，推荐使用
2）在set方法的上面
@Autowired第一种使用方式---byType 1.在Student中先声明引用类型school，在声明school类的语句上面加入@Autowired
package com.example.ba03;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("myStudent")
public class Student {
@Value(value = "张飞")
private String name;
@Value(value = "27")
private Integer age;
/*引用类型
* @Autowired：spring框架提供的注解，实现引用类型的赋值。
* spring中通过注解给引用类型赋值，使用的是自动注入原理，支持byName，byType
* @Autowired：默认使用的是byType自动注入
*
* 位置：1）在属性定义的上面，无需set方法，推荐使用
* 2）在set方法的上面
* */
@Autowired
private School school;
public void setName(String name) {
this.name = name;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", school=" + school +
'}';
}
}
2.声明School对象，通过注解在School类上面加入@Component以及给属性的对象赋值；另外也可以通过配置文件来赋值
package com.example.ba03;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "北京大学")
private String name;
@Value(value = "北京海淀区")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="com.example.ba03"/>
<bean id="myXueXiao" class="com.example.ba03.School">
<property name="name" value="清华大学"/>
<property name="address" value="北京"/>
</bean>
</beans>
@Autowired第二种使用方式---byName
如果要使用byName方式，需要做的是： 1.在属性上面加入@Autowired 2.在属性上面加入@@Qualifier(value="bean的id")：表示使用指定名称的bean完成赋值
package com.example.ba04;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("myStudent")
public class Student {
@Value(value = "张飞")
private String name;
@Value(value = "27")
private Integer age;
/*引用类型
* @Autowired：spring框架提供的注解，实现引用类型的赋值。
* spring中通过注解给引用类型赋值，使用的是自动注入原理，支持byName，byType
* @Autowired：默认使用的是byType自动注入
*
* 位置：1）在属性定义的上面，无需set方法，推荐使用
* 2）在set方法的上面
*
* */
@Autowired
@Qualifier("mySchool")
private School school;
public void setName(String name) {
this.name = name;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", school=" + school +
'}';
}
}
声明School对象，通过注解在School类上面加入@Component以及给属性的对象赋值
package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}package com.example.ba04;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
@Component("mySchool")
public class School {
@Value(value = "中山大学")
private String name;
@Value(value = "广州")
private String address;
public void setName(String name) {
this.name = name;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "School{" +
"name='" + name + '\'' +
", address='" + address + '\'' +
'}';
}
}
这篇关于注解的使用之Autowired注解的使用的文章就介绍到这儿，希望我们推荐的文章对大家有所帮助，也希望大家多多支持为之网！
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