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一、注解基本使用介绍
注解注入各种类型的Bean。
二、环境
1.Pom
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.3.7.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.7.RELEASE</version>
</dependency>
<!--单元测试-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
三、代码实现
1.构造方法注入
（1）AnotherBean 类
package com.spring.ioc;
import org.springframework.stereotype.Component;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
public class AnotherBean {
}（2）MyBean类
package com.spring.ioc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
public class MyBean {
private AnotherBean anotherBean1;
@Autowired
public MyBean(AnotherBean anotherBean1) {
this.anotherBean1 = anotherBean1;
}
@Override
public String toString() {
return "MyBean{" +
"anotherBean1=" + anotherBean1 +
'}';
}
}
（3）MyConfiguration类（相当于之前的spring.xml文件）
package com.spring.ioc;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
}（4）测试
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
}
}结果
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@548a102f}2.Set方法注入
（1）修改MyBean类
添加属性anotherBean2以及对应set方法，同时重写toString方法
package com.spring.ioc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
public class MyBean {
//构造方法
private AnotherBean anotherBean1;
//Set方法
private AnotherBean anotherBean2;
@Autowired
public void setAnotherBean2(AnotherBean anotherBean2) {
this.anotherBean2 = anotherBean2;
}
@Autowired
public MyBean(AnotherBean anotherBean1) {
this.anotherBean1 = anotherBean1;
}
@Override
public String toString() {
return "MyBean{" +
"anotherBean1=" + anotherBean1 +
", anotherBean2=" + anotherBean2 +
'}';
}
}（2）测试代码
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
}
}结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@1a84f40f, anotherBean2=com.spring.ioc.AnotherBean@1a84f40f}3.直接属性上注解
（1）修改MyBean类
package com.spring.ioc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
//@Scope
public class MyBean {
//构造方法
private AnotherBean anotherBean1;
//Set方法
private AnotherBean anotherBean2;
//属性直接注解
@Autowired
private AnotherBean anotherBean3;
@Autowired
public void setAnotherBean2(AnotherBean anotherBean2) {
this.anotherBean2 = anotherBean2;
}
@Autowired
public MyBean(AnotherBean anotherBean1) {
this.anotherBean1 = anotherBean1;
}
@Override
public String toString() {
return "MyBean{" +
"anotherBean1=" + anotherBean1 +
", anotherBean2=" + anotherBean2 +
", anotherBean3=" + anotherBean3 +
'}';
}
}（2）测试
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
}
}
结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@258e2e41, anotherBean2=com.spring.ioc.AnotherBean@258e2e41, anotherBean3=com.spring.ioc.AnotherBean@258e2e41}4.List注入
（1）MyBean：List直接set注入
package com.spring.ioc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import java.util.List;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
//@Scope
public class MyBean {
//构造方法
private AnotherBean anotherBean1;
//Set方法
private AnotherBean anotherBean2;
//属性直接注解
@Autowired
private AnotherBean anotherBean3;
public List<String> getStringList() {
return stringList;
}
@Autowired
public void setStringList(List<String> stringList) {
this.stringList = stringList;
}
//List注入
private List<String> stringList;
@Autowired
public void setAnotherBean2(AnotherBean anotherBean2) {
this.anotherBean2 = anotherBean2;
}
@Autowired
public MyBean(AnotherBean anotherBean1) {
this.anotherBean1 = anotherBean1;
}
@Override
public String toString() {
return "MyBean{" +
"anotherBean1=" + anotherBean1 +
", anotherBean2=" + anotherBean2 +
", anotherBean3=" + anotherBean3 +
'}';
}
}
（2）MyConfiguration 类
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
}（3）测试代码
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
}
}结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@6a01e23, anotherBean2=com.spring.ioc.AnotherBean@6a01e23, anotherBean3=com.spring.ioc.AnotherBean@6a01e23}
s = aaa
s = bbb（4）第二种注入list方法：修改MyConfiguration
即：如果一个list的属性需要注入，则spring会在上下文中寻找List对应泛型的所有实例，并且注入到里面
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
// @Bean
// public List<String> stringList(){
// List<String> list=new ArrayList<String>();
// list.add("aaa");
// list.add("bbb");
// return list;
// }
@Bean
public String string1(){
return "33333";
}
@Bean
public String string2(){
return "222222";
}
}测试代码结果：
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
}
}结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@6dbb137d, anotherBean2=com.spring.ioc.AnotherBean@6dbb137d, anotherBean3=com.spring.ioc.AnotherBean@6dbb137d}
s = 33333
s = 222222（5）如果两种注入都存在，则按照第二种方法注入；如果需要第一种，则需要指定Bean的id。
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean("stringList")
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
@Bean
public String string1(){
return "33333";
}
@Bean
public String string2(){
return "222222";
}
}修改myBean，指定注入id
测试代码：
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
}
}结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@6b19b79, anotherBean2=com.spring.ioc.AnotherBean@6b19b79, anotherBean3=com.spring.ioc.AnotherBean@6b19b79}
s = aaa
s = bbb（6）控制list的元素数据的顺序
通过@Order方法注入顺序，序号越小越靠前
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean("stringList")
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
@Bean
@Order(54)
public String string1(){
return "33333";
}
@Bean
@Order(4)
public String string2(){
return "222222";
}
}MyBean类去除，注入Bean的id
测试代码
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
}
}结果：222222在前面
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@43301423, anotherBean2=com.spring.ioc.AnotherBean@43301423, anotherBean3=com.spring.ioc.AnotherBean@43301423}
s = 222222
s = 333335.Map注入
（1）MyBean类，添加map属性
（2）Config类
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean("stringList")
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
@Bean
@Order(54)
public String string1(){
return "33333";
}
@Bean
@Order(4)
public String string2(){
return "222222";
}
@Bean
public Map<String,Integer> integerMap(){
Map<String ,Integer> map =new HashMap<String, Integer>();
map.put("aaa",123456);
map.put("bbb",234567);
return map;
}
}（3）测试
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean("stringList")
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
@Bean
@Order(54)
public String string1(){
return "33333";
}
@Bean
@Order(4)
public String string2(){
return "222222";
}
//map的注入bean
@Bean
public Map<String,Integer> integerMap(){
Map<String ,Integer> map =new HashMap<String, Integer>();
map.put("aaa",123456);
map.put("bbb",234567);
return map;
}
}
（4）第二种方法注入，在MyConfiguration 类
package com.spring.ioc;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
@Configuration
@ComponentScan("com.spring.ioc")
public class MyConfiguration {
@Bean("stringList")
public List<String> stringList(){
List<String> list=new ArrayList<String>();
list.add("aaa");
list.add("bbb");
return list;
}
@Bean
@Order(54)
public String string1(){
return "33333";
}
@Bean
@Order(4)
public String string2(){
return "222222";
}
//map的注入bean
@Bean
public Map<String,Integer> integerMap(){
Map<String ,Integer> map =new HashMap<String, Integer>();
map.put("aaa",123456);
map.put("bbb",234567);
return map;
}
//map第二种方法
@Bean("ini1")
public Integer integer1(){
return 222222;
}
@Bean("int2")
public Integer integer2(){
return 333333;
}
}测试代码不变，结果默认map的key为对应Bean的id：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@51e5fc98, anotherBean2=com.spring.ioc.AnotherBean@51e5fc98, anotherBean3=com.spring.ioc.AnotherBean@51e5fc98}
s = 222222
s = 33333
entry = ini1=222222
entry = int2=333333
6.简单类型String
（1）MyBean类
package com.spring.ioc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import java.util.List;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
@Component
//@Scope
public class MyBean {
//构造方法
private AnotherBean anotherBean1;
//Set方法
private AnotherBean anotherBean2;
//属性直接注解
@Autowired
private AnotherBean anotherBean3;
public List<String> getStringList() {
return stringList;
}
@Autowired
// @Qualifier("stringList")
public void setStringList(List<String> stringList) {
this.stringList = stringList;
}
//List注入
private List<String> stringList;
//map注入
private Map<String,Integer> integerMap;
//string
private String string;
public String getString() {
return string;
}
@Value("string11111")
public void setString(String string) {
this.string = string;
}
public Map<String, Integer> getIntegerMap() {
return integerMap;
}
@Autowired
public void setIntegerMap(Map<String, Integer> integerMap) {
this.integerMap = integerMap;
}
@Autowired
public void setAnotherBean2(AnotherBean anotherBean2) {
this.anotherBean2 = anotherBean2;
}
@Autowired
public MyBean(AnotherBean anotherBean1) {
this.anotherBean1 = anotherBean1;
}
@Override
public String toString() {
return "MyBean{" +
"anotherBean1=" + anotherBean1 +
", anotherBean2=" + anotherBean2 +
", anotherBean3=" + anotherBean3 +
", stringList=" + stringList +
", integerMap=" + integerMap +
", string='" + string + '\'' +
'}';
}
}
（2）测试代码
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
//很帅气
for (Map.Entry<String, Integer> stringIntegerEntry : myBean.getIntegerMap().entrySet()) {
System.out.println("entry = "+ stringIntegerEntry);
}
//string类型
System.out.println(myBean.getString());
}
}
结果：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@48fa0f47, anotherBean2=com.spring.ioc.AnotherBean@48fa0f47, anotherBean3=com.spring.ioc.AnotherBean@48fa0f47, stringList=[222222, 33333], integerMap={ini1=222222, int2=333333}, string='string11111'}
s = 222222
s = 33333
entry = ini1=222222
entry = int2=333333
string111117.常用接口注入
（1）MyBean类
（2）测试代码
package com.spring.ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.Map;
/**
* Created by Administrator on 2019/10/26.
*/
public class testcode {
@Test
public void test(){
ApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);
MyBean myBean=context.getBean("myBean",MyBean.class);
System.out.println("myBean = " + myBean);
for (String s:myBean.getStringList()){
System.out.println("s = "+s);
}
//很帅气
for (Map.Entry<String, Integer> stringIntegerEntry : myBean.getIntegerMap().entrySet()) {
System.out.println("entry = "+ stringIntegerEntry);
}
//string类型
System.out.println(myBean.getString());
//接口测试
AnotherBean anotherBean = myBean.getContext().getBean("anotherBean", AnotherBean.class);
System.out.println("anotherBean = " + anotherBean);
}
}
结果获得anotherBean：
myBean = MyBean{anotherBean1=com.spring.ioc.AnotherBean@75329a49, anotherBean2=com.spring.ioc.AnotherBean@75329a49, anotherBean3=com.spring.ioc.AnotherBean@75329a49, stringList=[222222, 33333], integerMap={ini1=222222, int2=333333}, string='string11111'}
s = 222222
s = 33333
entry = ini1=222222
entry = int2=333333
string11111
anotherBean = com.spring.ioc.AnotherBean@75329a49
四、总结
1.@Bean和@Component区别
@Bean注解在方法上；@Component注解在类上，两者生成的实例，供spring使用。