spring框架中的对象创建策略是什么

我是spring框架的新手，只是在玩它。在这期间，我遇到了一个奇怪的输出。我试着调试。但是没有得到答案（尽管我没有深入研究框架代码）

我想做什么：我只想创建一个

User

类的实例。值

{city='Sirsa2'，i1=12}

我有以下四个代码文件：

IntTest.java

package Task4;

import org.springframework.stereotype.Service;

//Just creating an integer. Since Integer class is final so, I have to extend Number class. So I also needed to override abstract metods. 
@Service
public class IntTest extends Number {
    Integer i1;

    public Integer getI1() {
        return i1;
    }

    public void setI1(Integer i1) {
        this.i1 = i1;
    }

    public IntTest() {
        i1 = 90;
    }
    @Override
    public double doubleValue() {
        return i1.doubleValue();
    }

    @Override
    public float floatValue() {
        return i1.floatValue();
    }

    @Override
    public int intValue() {
        return i1.intValue();
    }

    @Override
    public long longValue() {
        return i1.longValue();
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class Address {
    private String city;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class User {

    Address address;
    Integer i1;

    User(Address address, IntTest t1)
    {
        this.address= address;
        i1 = t1.getI1();
        System.out.println("1. Point " + t1.getI1());
    }

    public void getInfo() {
        System.out.println(address.getCity() + " | "+i1.intValue());
    }
}

package Task4;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("Task3")
public class Config {}

package Task4;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainClass {
    public static void main(String args[]) {
        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
        context.register(Config.class);
        context.refresh();
        Address address1=(Address)context.getBean(Address.class);
        address1.setCity("Sirsa");

        Address address2=(Address)context.getBean(Address.class);
        address2.setCity("Sirsa2");

        IntTest intTest=(IntTest)context.getBean(IntTest.class);
        System.out.println("2. Point " + intTest.getI1());
        intTest.setI1(12);
        System.out.println("3. Point " + intTest.getI1());

        User user=(User) context.getBean(User.class);
        user.getInfo();
    }
}

Address.java

package Task4;

import org.springframework.stereotype.Service;

//Just creating an integer. Since Integer class is final so, I have to extend Number class. So I also needed to override abstract metods. 
@Service
public class IntTest extends Number {
    Integer i1;

    public Integer getI1() {
        return i1;
    }

    public void setI1(Integer i1) {
        this.i1 = i1;
    }

    public IntTest() {
        i1 = 90;
    }
    @Override
    public double doubleValue() {
        return i1.doubleValue();
    }

    @Override
    public float floatValue() {
        return i1.floatValue();
    }

    @Override
    public int intValue() {
        return i1.intValue();
    }

    @Override
    public long longValue() {
        return i1.longValue();
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class Address {
    private String city;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class User {

    Address address;
    Integer i1;

    User(Address address, IntTest t1)
    {
        this.address= address;
        i1 = t1.getI1();
        System.out.println("1. Point " + t1.getI1());
    }

    public void getInfo() {
        System.out.println(address.getCity() + " | "+i1.intValue());
    }
}

package Task4;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("Task3")
public class Config {}

package Task4;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainClass {
    public static void main(String args[]) {
        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
        context.register(Config.class);
        context.refresh();
        Address address1=(Address)context.getBean(Address.class);
        address1.setCity("Sirsa");

        Address address2=(Address)context.getBean(Address.class);
        address2.setCity("Sirsa2");

        IntTest intTest=(IntTest)context.getBean(IntTest.class);
        System.out.println("2. Point " + intTest.getI1());
        intTest.setI1(12);
        System.out.println("3. Point " + intTest.getI1());

        User user=(User) context.getBean(User.class);
        user.getInfo();
    }
}

User.java

package Task4;

import org.springframework.stereotype.Service;

//Just creating an integer. Since Integer class is final so, I have to extend Number class. So I also needed to override abstract metods. 
@Service
public class IntTest extends Number {
    Integer i1;

    public Integer getI1() {
        return i1;
    }

    public void setI1(Integer i1) {
        this.i1 = i1;
    }

    public IntTest() {
        i1 = 90;
    }
    @Override
    public double doubleValue() {
        return i1.doubleValue();
    }

    @Override
    public float floatValue() {
        return i1.floatValue();
    }

    @Override
    public int intValue() {
        return i1.intValue();
    }

    @Override
    public long longValue() {
        return i1.longValue();
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class Address {
    private String city;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class User {

    Address address;
    Integer i1;

    User(Address address, IntTest t1)
    {
        this.address= address;
        i1 = t1.getI1();
        System.out.println("1. Point " + t1.getI1());
    }

    public void getInfo() {
        System.out.println(address.getCity() + " | "+i1.intValue());
    }
}

package Task4;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("Task3")
public class Config {}

package Task4;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainClass {
    public static void main(String args[]) {
        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
        context.register(Config.class);
        context.refresh();
        Address address1=(Address)context.getBean(Address.class);
        address1.setCity("Sirsa");

        Address address2=(Address)context.getBean(Address.class);
        address2.setCity("Sirsa2");

        IntTest intTest=(IntTest)context.getBean(IntTest.class);
        System.out.println("2. Point " + intTest.getI1());
        intTest.setI1(12);
        System.out.println("3. Point " + intTest.getI1());

        User user=(User) context.getBean(User.class);
        user.getInfo();
    }
}

Config.java

package Task4;

import org.springframework.stereotype.Service;

//Just creating an integer. Since Integer class is final so, I have to extend Number class. So I also needed to override abstract metods. 
@Service
public class IntTest extends Number {
    Integer i1;

    public Integer getI1() {
        return i1;
    }

    public void setI1(Integer i1) {
        this.i1 = i1;
    }

    public IntTest() {
        i1 = 90;
    }
    @Override
    public double doubleValue() {
        return i1.doubleValue();
    }

    @Override
    public float floatValue() {
        return i1.floatValue();
    }

    @Override
    public int intValue() {
        return i1.intValue();
    }

    @Override
    public long longValue() {
        return i1.longValue();
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class Address {
    private String city;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class User {

    Address address;
    Integer i1;

    User(Address address, IntTest t1)
    {
        this.address= address;
        i1 = t1.getI1();
        System.out.println("1. Point " + t1.getI1());
    }

    public void getInfo() {
        System.out.println(address.getCity() + " | "+i1.intValue());
    }
}

package Task4;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("Task3")
public class Config {}

package Task4;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainClass {
    public static void main(String args[]) {
        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
        context.register(Config.class);
        context.refresh();
        Address address1=(Address)context.getBean(Address.class);
        address1.setCity("Sirsa");

        Address address2=(Address)context.getBean(Address.class);
        address2.setCity("Sirsa2");

        IntTest intTest=(IntTest)context.getBean(IntTest.class);
        System.out.println("2. Point " + intTest.getI1());
        intTest.setI1(12);
        System.out.println("3. Point " + intTest.getI1());

        User user=(User) context.getBean(User.class);
        user.getInfo();
    }
}

MainClass.java

package Task4;

import org.springframework.stereotype.Service;

//Just creating an integer. Since Integer class is final so, I have to extend Number class. So I also needed to override abstract metods. 
@Service
public class IntTest extends Number {
    Integer i1;

    public Integer getI1() {
        return i1;
    }

    public void setI1(Integer i1) {
        this.i1 = i1;
    }

    public IntTest() {
        i1 = 90;
    }
    @Override
    public double doubleValue() {
        return i1.doubleValue();
    }

    @Override
    public float floatValue() {
        return i1.floatValue();
    }

    @Override
    public int intValue() {
        return i1.intValue();
    }

    @Override
    public long longValue() {
        return i1.longValue();
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class Address {
    private String city;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }
}

package Task4;

import org.springframework.stereotype.Service;

@Service
public class User {

    Address address;
    Integer i1;

    User(Address address, IntTest t1)
    {
        this.address= address;
        i1 = t1.getI1();
        System.out.println("1. Point " + t1.getI1());
    }

    public void getInfo() {
        System.out.println(address.getCity() + " | "+i1.intValue());
    }
}

package Task4;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("Task3")
public class Config {}

package Task4;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainClass {
    public static void main(String args[]) {
        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext();
        context.register(Config.class);
        context.refresh();
        Address address1=(Address)context.getBean(Address.class);
        address1.setCity("Sirsa");

        Address address2=(Address)context.getBean(Address.class);
        address2.setCity("Sirsa2");

        IntTest intTest=(IntTest)context.getBean(IntTest.class);
        System.out.println("2. Point " + intTest.getI1());
        intTest.setI1(12);
        System.out.println("3. Point " + intTest.getI1());

        User user=(User) context.getBean(User.class);
        user.getInfo();
    }
}

当我作为JavaApplication运行

MainClass.java

时，我将获得以下输出：

1. Point 90
2. Point 90
3. Point 12
Sirsa2 | 90

但期望：

2. Point 90
3. Point 12
1. Point 12
Sirsa2 | 12

我不确定对象是如何创建的。但我认为：

• 要创建

  User

  类的对象，将调用构造函数

  User（地址，IntTest t1）

• 因为在构造函数中传递的

  Address

  类的对象是

  address1

  变量（因为它的值被打印为'Sirsa2'，而不是'Sirsa'）。所以我希望

  IntTest

  类的对象应该是

  i1

  变量
• 另外，我希望

  User

  类的构造函数应该在最后调用。但就产量而言，情况并非如此
• 当我调试它时，我知道它正在创建第

  context.refresh（）行中的对象在
  MainClass.java
  中。但它是如何将城市的值设置为
  Sirsa2
  ，而不是将
  i1
  的值设置为12的

---

我使用的是

Eclipse（Oxygen）

，

java1.8.0\u121

，

spring-framework-4.3.9。默认情况下，发布
和
commons-logging-1.2
，ApplicationContext实现急切地创建和配置所有单例bean，作为初始化过程的一部分。初始化过程在应用程序启动期间进行。之后，它将继续注入对象。默认情况下，对象是单例作用域，因此对整个应用程序都是相同的。是的，它将这样工作只有



因为
System.out.println（“1.Point”+t1.getI1（））位于用户对象的构造函数中，同时启动应用程序spring尝试为此类用户创建对象，构造函数被调用，因此打印point1

如果你想要以下行为
2.第90点
3.第12点
1.第12点
Sirsa2 | 12

在您的bean上设置lazy init=“true”
默认情况下，Spring bean是单例的，这意味着只创建了一个bean实例，可以在使用它的任何地方重用它。请参阅Spring框架文档中的。@Jesper感谢您提供此信息。但是为什么没有按照我的期望设定值呢。我知道我的例外很奇怪。但spring框架的行为也是如此；）（因为它选择的是
Address
的值，而不是
IntTest
）请注意，由于它们是单例，因此只有一个
Address
对象，而
address1
和
address2
都指向同一个对象。您可以执行
address1.setCity（“Sirsa”）但行
地址2.setCity（“Sirsa2”）将覆盖它，因为它是同一个对象。同样，只有一个
IntTest
对象。因为spring在spring容器中创建了所有对象。它们首先在应用程序启动时初始化。之后，它将继续注入对象。默认情况下，这些对象是单例作用域，因此对于整个应用程序来说都是相同的，但这并不重要。是的，您可以这样做吗是的，它只会像这样工作。