Spring框架（二）

在myEclipse上运行

1.配置好Maven的环境变量

2.创建Maven项目，在pom.xml里面编写要下载的包

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>edu.edu.edu</groupId>
  <artifactId>es</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
   <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.0.8.RELEASE</version>
</dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.0.8.RELEASE</version>
</dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.0.8.RELEASE</version>
</dependency>
  <!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
</dependency>
  </dependencies>
  
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.6</source>
          <target>1.6</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
  
</project>

3.在类路径下编写配置文件

<?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
http://www.springframework.org/schema/context/spring-context.xsd" >
 
 <!-- 找到包下的所有子包，当有Component时装入类 -->
<context:component-scan base-package="edu"></context:component-scan>
</beans>

<context:component-scan base-package="edu"></context:component-scan>是遍历该报下的所有子包里的类，当有@Component时，就配置该类，默认id为类名，name为包名加类名

4.写类

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

@Component
public class User {
	@Value("张三")
   private String name;
	@Value("12")
   private int id;
	@Value("男")
   private String sex;
public String getName() {
	return name;
}
public void setName(String name) {
	this.name = name;
}
public int getId() {
	return id;
}
public void setId(int id) {
	this.id = id;
}
public String getSex() {
	return sex;
}
public void setSex(String sex) {
	this.sex = sex;
}
  
   
}

@Value()给变量赋值

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;

//@Component("stu")
//以下三个@Component的三个衍生注解:

//@Repository("stu")  //持久层
//@Service("stu")   //业务层
@Controller("stu")   //WEB层
//以上这几种都可以
@Scope("prototype")   //重新一个类，遇到相同的类重新分配地址
public class UserDao {
	@Value("西安")   //赋值
	private String a;
	@Value("北京")
	private String d;
	@Autowired  //调用另外一个类（自动装配）
 private User user;
	public User getUser() {
	return user;
}
public void setUser(User user) {
	this.user = user;
}
public String getA() {
	return a;
}
public void setA(String a) {
	this.a = a;
}
public String getD() {
	return d;
}
public void setD(String d) {
	this.d = d;
}
	
}

4.执行配置里的类

public class Test1 {
   @Test
	public void test1(){
		ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
		UserDao u = ac.getBean(UserDao.class);
		System.out.println(u.getA()+" :"+u.getD());
		System.out.println(u.getUser().getId()+" "+u.getUser().getName()+" "+u.getUser().getSex());
		UserDao u1 = ac.getBean(UserDao.class);
		System.out.println(u==u1);
		UserDao u2 = (UserDao) ac.getBean("stu");  //@Component("stu")
		System.out.println(u==u2);
		System.out.println(u.getUser()==u1.getUser());
	}
}

如果不做任何处理，每次给相同类分配的地址相同。

但是给类前面加@Scope("prototype")则每次分配内存的地址不同

UserDao u = ac.getBean(UserDao.class);用反射调用类

UserDao u2 = (UserDao) ac.getBean("stu"); //@Component("stu") 用配置的id名来调用，或者默认的id名

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