JAVA & .NET創建對象構造函數調用順序
JAVA
定義Person類
package models;
public class Person {
public Person() {
System.out.println("person constructor");
}
{
System.out.println("person init block");
}
static {
System.out.println("person static block");
}
}
定義Chinese類
package models;
public class Chinese extends Person {
public Chinese() {
// super();
System.out.println("chinese constructor");
}
{
System.out.println("chinese init block");
}
{
System.out.println("chinese init block2");
}
static {
System.out.println("chinese static block");
}
static {
System.out.println("chinese static block 2");
}
}
創建Chinese類實例
public class Program {
public static void main(String[] args) {
new Chinese();
}
}
輸出結果如下:
person static block
chinese static block
chinese static block 2
person init block
person constructor
chinese init block
chinese init block2
chinese constructor
執行順序爲:
基類靜態初始化塊——當前類靜態初始化塊——基類初始化塊——基類構造函數——當前類初始化塊——當前類構造函數
.NET
與JAVA相比,.NET中沒有初始化塊及靜態初始化塊
定義類型如下:
class Person
{
public Person()
{
Console.WriteLine("person constructor");
}
static Person()
{
Console.WriteLine("person static constructor");
}
}
class Chinese : Person
{
public Chinese()
{
Console.WriteLine("chinese constructor");
}
static Chinese()
{
Console.WriteLine("chinese static constructor");
}
}
創建對象:
class Program
{
static void Main(string[] args)
{
new Chinese();
}
}
輸出結果如下:
chinese static constructor
person static constructor
person constructor
chinese constructor
執行順序爲:
當前類靜態構造函數——基類靜態構造函數——基類構造函數——當前類構造函數
小結
JAVA與.NET創建對象時都是先執行靜態代碼塊後執行非靜態代碼塊;
JAVA先執行基類中的靜態及非靜態代碼塊;
.NET先執行基類中的靜態代碼塊,先執行當前類中的實例構造函數;