Spring – 带有集合的构造函数注入

在构造函数注入中，依赖注入将在构造函数的帮助下注入。现在要将依赖注入设置为bean中的构造函数依赖注入（CDI），它是通过bean配置文件完成的。为此，要在构造函数依赖注入中设置的属性在标签下声明豆配置文件。

例子：

Java

package com.geeksforgeeks.org;
  
import com.geeksforgeeks.org.IGeek;
  
public class GFG {
  
    // The object of the interface IGeek
    IGeek geek;
  
    // Constructor to set the CDI
    GFG(IGeek geek) { this.geek = geek; }
}

在 bean-config 文件中设置 CDI：

构造函数注入与集合

Spring 框架为我们提供了通过 Spring 应用程序中的构造函数注入集合值的工具。 标签内可以使用以下集合：

• 列表
• 放
• 地图

例子：

1) 雇员。Java

创建一个员工类：

Java

package com.geeksforgeeks.org;
  
import com.geeksforgeeks.org.IGeek;
import java.util.List;
  
public class Employee {
    private String name;
    private String employeeID;
    private String department;
    private List address;
  
    public Employee(List address)
    {
        this.address = (List)address;
    }
  
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public String getemployeeID() { return employeeID; }
    public void setemployeeID(String employeeID)
    {
        this.employeeID = employeeID;
    }
    public String getdepartment() { return department; }
    public void setdepartment(String department)
    {
        this.department = department;
    }
  
    public List getAddress() { return address; }
  
    public void display()
    {
        System.out.println("Name: " + getName());
        System.out.println("Employee ID: "
                           + getEmployeeID());
        System.out.println("Department: "
                           + getDepartment());
        System.out.println("Address: " + getAddress());
    }
}

2) applicationContext.xml

要定义列表，请使用 constructor-arg 的列表元素。

XML

  
  
    
      
          
         
         
          
              
                Gurugram  
                Haryana  
                India  
              
          
      
    

3) 测试。Java

测试弹簧应用程序：

Java

package com.geeksforgeeks.org;
  
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
  
public class Test {
    public static void main(String[] args)
    {
        Resource resource = new ClassPathResource(
            "applicationContext.xml");
        BeanFactory factory = new XmlBeanFactory(resource);
  
        Employee e = (Employee)factory.getBean("employee");
        e.display();
    }
}

输出：

Name: Ram
Employee ID: 101
Department: Software testing
Address: [Gurugram, Haryana, India]