bean的自动装配
在Spring中由三种装配方式:
-
xml中显式的配置
-
java中显式的配置
-
隐式的自动装配bean
1.环境搭建
Dog.java:
package com.kakafa.pojo;
public class Dog {
public void shout(){
System.out.println("bark!");
}
}
Cat.java:
package com.kakafa.pojo;
public class Cat {
public void shout(){
System.out.println("miao!");
}
}
People.java:
package com.kakafa.pojo;
public class People {
private Dog dog;
private Cat cat;
private String name;
public Dog getDog() {
return dog;
}
public void setDog(Dog dog) {
this.dog = dog;
}
public Cat getCat() {
return cat;
}
public void setCat(Cat cat) {
this.cat = cat;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "People{" +
"dog=" + dog +
", cat=" + cat +
", name='" + name + '\'' +
'}';
}
}
beans.xml:
<?xml version="1.0" encoding="UTF-8"?>
test:
import com.kakafa.pojo.People;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MyTest {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
People people = context.getBean("people", People.class);
people.getCat().shout();
people.getDog().shout();
}
}
2.自动装配
原来:
自动装配:
1.byName
- byName只能取到小写,大写取不到;
- 不区分大小写的说法不准确,set/get方法生成会自动将属性首字母大写,所以Spring也只是会自动把set和get后面的第一个字符变为小写。
2.byType