java中对象的初始化与构造器
2014-02-25 20:58
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例子：一个天体数据类：
还可以使用如下的构造器，调整初始化顺序：
复制构造器：
class Body
{
public long idNum;
public String name;
public Body orbits;
public static long nextID;
}可以做天体对象的创建与初始化：Body Sun = new Body(); Sun.idNum = Body.nextID++; Sun.name = "Sol"; Sun.orbits = null; Body earth = new Body(); earth.idNum = Body.nextID++; earth.name = "Earth"; earth.orbits = Sun;使用构造器：
class Body
{
public long idNum;
public String name = "<unnamed>";
public Body orbits = null;
public static long nextID = 0;
Body(){
idNum = nextID++;
}
}初试化对象代码如下：Body Sun = new Body(); Sun.name = "Sol"; Body earth = new Body(); earth.name = "Earth"; earth.orbits = Sun;Body构造器代用发生在name和orbits初始化之后
还可以使用如下的构造器，调整初始化顺序：
Body(String bodyName, Body orbitdAround) {
this();
name = bodyName;
orbits = orbitdAround;
}初始化代码如下：Body Sun = new Body("Sol", null);
Body earth = new Body("Earth", Sun);还可以将构造器的第二个参数设置为null：Body(String bodyName) {
this(bodyName, null);
}复制构造器：
Body(Body other) {
idNum = other.idNum;
name = other.name;
orbits = other.orbits;
}
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