[英]Create instance of a class and set variables
在C#中,您可以创建一个类的实例并同时设置变量的值:
public class Object
{
public virtual long Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int Version { get; set; }
public long ParentId { get; set; }
}
public class Start
{
Object object= new Object()
{
Id = 1,
Name = name,
ParentId = parentId,
Description = null,
Version= 2
};
}
Java中也可能吗?如何?
创建实例时设置值的标准方法是仅具有一个构造函数:
class ExampleObject {
long id;
String name;
String description;
int version;
long parentId;
public ExampleObject(final long id, final String name, final String description, final int version, final long parentId) {
this.id = id;
this.name = name;
this.description = description;
this.version = version;
this.parentId = parentId;
}
}
然后像这样调用它:
ExampleObject exampleObject = new ExampleObject(1, name, null, 2, parentId);
可以使用与您所显示的语法类似的语法,但是它有很多缺点,您在使用它之前应该进行研究(并且您也不能在其中使用变量):
ExampleObject exampleObject = new ExampleObject() {{
id = 1;
name = "";
parentId = 2;
description = null;
version = 2;
}};
class ExampleObject {
long id;
String name;
String description;
int version;
long parentId;
}
这是用静态初始化程序块创建一个匿名类。 静态初始化程序块如下所示:
class ExampleObject {
long id;
String name;
String description;
int version;
long parentId;
{
id = 1;
name = "";
parentId = 2;
description = null;
version = 2;
}
}
您可以创建一个接受所有字段值的构造函数。 这样,您可以创建该对象的新实例并同时设置所需的值:
public class MyClass {
public long id;
public String name;
public String description;
public int version;
public long parentId;
/** Constructor **/
public MyClass(long id, String name, String description, int version, long parentId) {
this.id = id;
this.name = name;
this.description = description;
this.version = version;
this.parentId = parentId;
}
}
public static void main(String args[]) {
MyClass myClass = new MyClass(1, "name", "description", 1, 1);
}
顺便说一下,不建议(尽管可以)在Java中命名一个类Object
,因为Java也有一个具有相同名称的类,并且所有 Java类都从其扩展(可能引起混淆)。
public class Object
{
public long id;
public String name;
public String description;
public int version;
public long parentId;
public Object(long Id,string Name,string Description,int Version,long Parent_Id)
{
this.Id =Id ;
this.Name =Name ;
this.Description =Description ;
this.Version =Version ;
}
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