public class Test {
public static void main(String[] args) {
Collection c =new ArrayList();
c.add(new Student("zhangsan",11));
c.add(new Student("lisi",11));
c.remove(new Student("lisi",11));
System.out.println(c);
}
}
输出结果是包名,而不是"zhangsan",11
public static void main(String[] args) {
Collection c =new ArrayList();
c.add(new Student("zhangsan",11));
c.add(new Student("lisi",11));
c.remove(new Student("lisi",11));
System.out.println(c);
}
}
输出结果是包名,而不是"zhangsan",11
或者打印的时候遍历一下
public class Student
{
private String name;
private int age;
public Student(String name,int age){
this.name=name;
this.age=age;
} public String toString(){
return name+","+age;
}
public static void main(String[] args)
{
Collection c =new ArrayList();
c.add(new Student("zhangsan",11));
c.add(new Student("lisi",11));
c.remove(new Student("lisi",11));
System.out.println(c); }}
Iterator<E> it = iterator();
if (! it.hasNext())
return "[]"; StringBuilder sb = new StringBuilder();
sb.append('[');
for (;;) {
E e = it.next();
sb.append(e == this ? "(this Collection)" : e);
if (! it.hasNext())
return sb.append(']').toString();
sb.append(',').append(' ');
}
}Object的
public String toString() {
return getClass().getName() + "@" + Integer.toHexString(hashCode());
}
public String toString() {
return "Student [name=" + name + ", age=" + age + "]";
}
进入Student类
按住shift+alt+s快捷键
选择Generate ToString() 选项 (倒数第四个)
亲测有效
如果你想直接这样输出集合里面对象的东西的话
需要在对象的类中重写toString方法
c.add(new Student("zhangsan",11));
c.add(new Student("lisi",11));
c.remove(new Student("lisi",11));
应该把 new Student() 放到外边
Student a = new Student("zhangsan",11);
Student b = new Student("lisi",11);
c.add(a);
c.add(b);
c.remove(b);
就是调用AbstractCollection的toStrin(),
你可以去看看源码