【Spring】set注入(掌握)

概念： spring调用类中的set方法，在set方法中可以完成属性赋值。 推荐使用。

Alt insert ---->xml 

对应包的spring配置文件：

String config = "bao1/applicationContext.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(config);

applicationContext.xml

Student.java

public class Student {
    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + ''' +
                ", age=" + age +
                '}';
    }
}

MyTest.java

@Test
public void test01(){
      String config = "bao1/applicationContext.xml";
      ApplicationContext ctx = new ClassPathXmlApplicationContext(config);
      Student student = (Student) ctx.getBean("mystudent");
      System.out.println("Studen:" + student);
}

此时没有给属性赋值：

简单类型的set注入： spring调用类的set()方法，通过set()方法完成属性赋值

 
	
    ...
 

applicationContext.xml

执行test01

在set方法中添加输出语句：

public class Student {
    private String name;
    private int age;

    public void setName(String name) {
        System.out.println("setName=="+name);
        this.name = name;
    }

    public void setAge(int age) {
        System.out.println("setAge=="+age);
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + ''' +
                ", age=" + age +
                '}';
    }
}

添加一个无参构造：

public class Student {
    private String name;
    private int age;

    public Student() {
        System.out.println("Student的无参数构造方法");
    }
    
    public void setName(String name) {
        System.out.println("setName=="+name);
        this.name = name;
    }

    public void setAge(int age) {
        System.out.println("setAge=="+age);
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + ''' +
                ", age=" + age +
                '}';
    }
}

若将set方法去掉则会报错：

set()方法里面是由自己实现的:

添加一个setEmail()方法:


给属性赋值看的是set方法,与属性名无关,与有没有属性无关,看的只是set方法,有set就是正确的

语法：

	 
	...

Student.java

public class Student {
    private String name;
    private int age;

    //引用类型
    private School school;

    public Student() {
        System.out.println("Student的无参数构造方法");
    }

    public void setName(String name) {
        System.out.println("setName=="+name);
        this.name = "Hello" + name;
    }
    
    public void setAge(int age) {
        System.out.println("setAge=="+age);
        this.age = age;
    }

    public void setSchool(School school) {
        System.out.println("setSchool==" + school);
        this.school = school;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + ''' +
                ", age=" + age +
                ", school=" + school +
                '}';
    }
}

School.java

public class School {
    private String name;
    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 + ''' +
                '}';
    }
}

用spring体现一下:

School声明在student前后的顺序无所谓(id和ref区分大小写)