注：参考了JIT(Java in thinking)，示例都是那里面的。
1、在一个类中，this可以表示该类的当前实例；例如：
public class Leaf {
private int i = 0;
Leaf increment() {
i++;
return this;
}
void print() {
System.out.println("i = " + i);
}
public static void main(String[] args) {
Leaf x = new Leaf();
x.increment().increment().increment().print();
}
} ///:~
2、若为一个类写了多个构造器，那么经常都需要在一个构造器里调用另一个构造器，以避免写重复的代码。这时可以使用this，例如：
//: Flower.java
// Calling constrUCtors with "this"
public class Flower {
private int petalCount = 0;
private String s = new String("null");
Flower(int petals) {
petalCount = petals;
System.out.println(
"Constructor w/ int arg only, petalCount= "
+ petalCount);
}
Flower(String ss) {
System.out.println(
"Constructor w/ String arg only, s=" + ss);
s = ss;
}
Flower(String s, int petals) {
this(petals);
//! this(s); // Can't call two!
this.s = s; // Another use of "this"
System.out.println("String & int args");
}
Flower() {
this("hi", 47);
System.out.println(
"default constructor (no args)");
}
void print() {
//! this(11); // Not inside non-constructor!
System.out.println(
"petalCount = " + petalCount + " s = "+ s);
}
public static void main(String[] args) {
Flower x = new Flower();
x.print();
}
} ///:~
而需要注重的是：在一个类A的内部类B中使用this它表示的并非是A.B的当前实例，而是A的当前实例；
