百度地图聚合示例_Java中的聚合：定义和示例

我就是我 2022-12-06 15:38 243阅读 0赞

百度地图聚合示例

*Aggregation* in Java* *is a relationship between two classes that is best described as a "has-a" and "whole/part" relationship. It is a more specialized version of the [association relationship][]. The aggregate class contains a reference to another class and is said to have ownership of that class. Each class referenced is considered to be *part-of* the aggregate class.

Java中的*聚合* * * 是两个类之间的关系，最好将其描述为“具有”和“整体/部分”关系。 它是[关联关系][association relationship]的更专业版本。 聚合类包含对另一个类的引用，并说拥有该类的所有权。 引用的每一个类被认为是*部分的*聚合类。

Ownership occurs because there can be no cyclic references in an aggregation relationship. If Class A contains a reference to Class B and Class B contains a reference to Class A then no clear ownership can be determined and the relationship is simply one of association.

发生所有权是因为聚合关系中不能存在循环引用。 如果A类包含对B类的引用，而B类包含对A类的引用，则无法确定明确的所有权，并且该关系只是关联之一。

For example, if you imagine that a Student class that stores information about individual students at a school. Now assume a Subject class that holds the details about a particular subject (e.g., history, geography). If the Student class is defined to contain a Subject object then it can be said that the Student object *has-a* Subject object. The Subject object also makes up *part-of* the Student object — after all, there is no student without a subject to study. The Student object, therefore, owns the Subject object.

例如，如果您想象一个学生类存储有关学校中各个学生的信息。 现在假定一个Subject类，其中包含有关特定主题的详细信息(例如，历史，地理)。 如果将Student类定义为包含Subject对象，则可以说Student对象*具有* \-Subject对象。 Subject对象也弥补了Student对象*部分的* \-毕竟，有没有受到研究没有学生。 因此，Student对象拥有Subject对象。

## 例子 **(** Examples **)** ##

Define an aggregation relationship between Student class and the Subject class as follows:

定义学生类和主题类之间的聚合关系，如下所示：

public class Subject {
        
    private String name;
    public void setName(String name)  {
        
    this.name = name;
    }
    public String getName()
    {
        
    return name;
    }
    }
    public class Student {
        
    private Subject[] studyAreas = new Subject[10];
    //the rest of the Stud

> 翻译自: [https://www.thoughtco.com/aggregation-2033995][https_www.thoughtco.com_aggregation-2033995]

百度地图聚合示例

[association relationship]: https://www.thoughtco.com/association-2034002
[https_www.thoughtco.com_aggregation-2033995]: https://www.thoughtco.com/aggregation-2033995