集合的操作步骤：

A:创建集合对象

B:创建元素对象

C:把元素添加到集合

D:遍历集合

集合的遍历方式：

Collection:迭代器,增强for

|--List:普通for

|--Set:

字符串(随便给 hello,world,java)

自定义对象(学生类)

class Student {

private String name;

private int age;

public Student() {}

public Student(String name,int age) {

this.name = name;

this.age = age;

}

public void setName(String name) {

this.name = name;

}

public String getName() {

return name;

}

public void setAge(int age) {

this.age = age;

}

public int getAge() {

return age;

}

}

1：Collection

A:字符串

Collection<String> c = new ArrayList<String>();

c.add("hello");

c.add("world");

c.add("java");

Iterator<String> it = c.iterator();

while(it.hasNext()) {

String s = it.next();

System.out.println(s);

}

for(String s : c) {

System.out.println(s);

}

B:自定义对象

Collection<Student> c = new ArrayList<Student>();

Student s1 = new Student("李连杰",50);

Student s2 = new Student("赵文卓",40);

Student s3 = new Student("吴京",30);

c.add(s1);

c.add(s2);

c.add(s3);

Iterator<Student> it = c.iterator();

while(it.hasNext()) {

Student s = it.next();

System.out.println(s.getName()+"---"+s.getAge());

}

for(Student s : c) {

System.out.println(s.getName()+"---"+s.getAge());

}

2：List

A:字符串

List<String> list = new ArrayList<String>();

list.add("hello");

list.add("world");

list.add("java");

Iterator<String> it = list.iterator();

while(it.hasNext()) {

String s = it.next();

System.out.println(s);

}

for(String s : list) {

System.out.println(s);

}

for(int x=0; x<list.size(); x++) {

String s = list.get(x);

System.out.println(s);

}

B:自定义对象

List<Student> list = new ArrayList<Student>();

Student s1 = new Student("李连杰",50);

Student s2 = new Student("赵文卓",40);

Student s3 = new Student("吴京",30);

list.add(s1);

list.add(s2);

list.add(s3);

Iterator<Student> it = list.iterator();

while(it.hasNext()) {

Student s = it.next();

System.out.println(s.getName()+"---"+s.getAge());

}

for(Student s : list) {

System.out.println(s.getName()+"---"+s.getAge());

}

for(int x=0; x<list.size(); x++) {

Student s = list.get(x);

System.out.println(s.getName()+"---"+s.getAge());

}

3：ArrayList(掌握 自己补齐)

A:字符串

ArrayList<String> array = new ArrayList<String>();

array.add("java");

array.add("hello");

array.add("world");

//普通for循环

for(int i =0; i<array.size(); i++) {

String s = array.get(i);

System.out.println(s);

}

//增强for

for(String s : array) {

System.out.println(s);

}

//迭代器

Iterator<String> it = array.iterator();

while(it.hasNext()) {

String s = it.next();

System.out.println(s);

}

B:自定义对象

ArrayList<Student> array = new ArrayList<Student>();

Student s1 = new Student("laozi",1000);

Student s2 = new Student("kongzi",100);

Student s3 = new Student("zhuangzi",10);

array.add(s1);

array.add(s2);

array.add(s3);

//普通for循环

for (int i = 0; i<array.size(); i++) {

Student s = array.get(i);

System.out.println(s.getName()+"---"+s.getAge());

}

//增强for循环

for (Student s : array) {

System.out.println(s.getName()+"---"+s.getAge());

}

//迭代器循环

for(Iterator<Student> it = array.iterator(); it.hasNext();) {

Student s = it.next();

System.out.println(s.getName()+"---"+s.getAge());

}

4：Vector(自己补齐)

A:字符串

Vector<String> vector = new Voctor<String>();

vector.add("java");

vector.add("hello");

vector.add("world");

//普通for循环

for(int i =0; i<vector.size(); i++) {

String s = vector.get(i);

System.out.println(s);

}

//增强for

for(String s : vector) {

System.out.println(s);

}

//迭代器

Iterator<String> it = vector.iterator();

while(it.hasNext()) {

String s = it.next();

System.out.println(s);

}

B:自定义对象

vectorList<Student> array = new vectorList<Student>();

Student s1 = new Student("laozi",1000);

Student s2 = new Student("kongzi",100);

Student s3 = new Student("zhuangzi",10);

vector.add(s1);

vector.add(s2);

vector.add(s3);

//普通for循环

for (int i = 0; i<vector.size(); i++) {

Student s = vector.get(i);

System.out.println(s.getName()+"---"+s.getAge());

}

//增强for循环

for (Student s : vector) {

System.out.println(s.getName()+"---"+s.getAge());

}

//迭代器循环

for(Iterator<Student> it = vector.iterator(); it.hasNext();) {

Student s = it.next();

System.out.println(s.getName()+"---"+s.getAge());

}

5：LinkedList(掌握 自己补齐)

6：Set

A:字符串

Set<String> set = new HashSet<String>();

set.add("hello");

set.add("world");

set.add("java");

Iterator<String> it = set.iterator();

while(it.hasNext()) {

String s = it.next();

System.out.println(s);

}

for(String s : set) {

System.out.println(s);

}

B:自定义对象

Set<Student> set = new HashSet<Student>();

Student s1 = new Student("李连杰",50);

Student s2 = new Student("赵文卓",40);

Student s3 = new Student("吴京",30);

set.add(s1);

set.add(s2);

set.add(s3);

Iterator<Student> it = set.iterator();

while(it.hasNext()) {

Student s = it.next();

System.out.println(s.getName()+"---"+s.getAge());

}

for(Student s : set) {

System.out.println(s.getName()+"---"+s.getAge());

}

7：HashSet(掌握 自己补齐)

存储自定义对象的时候，如果成员变量值相同，我们就认为是同一个元素。

8：TreeSet(掌握 自己补齐)

存储自定义对象的时候，如果成员变量值相同，我们就认为是同一个元素。

首先根据年龄从小到大排序，其次在根据姓名的长度排序。