Map集合的遍历方法

StudengDemo.java实体类

package com.listSetMapCollection.practice;
	
	/**
	 * 学生类
	 * @author Administrator
	 */
public class StudentDemo implements Comparable{
	/*
	 * 学生类
	 * 属性：姓名，学号，分数
	 */
	private String stuName;//姓名
	private String stuId;//学号
	private int stuGrade;//分数
	public StudentDemo(){}
	public StudentDemo(String stuName, String stuId, int stuGrade) {
		this.stuName = stuName;
		this.stuId = stuId;
		this.stuGrade = stuGrade;
	}
	public String getStuName() {
		return stuName;
	}
	public void setStuName(String stuName) {
		this.stuName = stuName;
	}
	public String getStuId() {
		return stuId;
	}
	public void setStuId(String stuId) {
		this.stuId = stuId;
	}
	public int getStuGrade() {
		return stuGrade;
	}
	public void setStuGrade(int stuGrade) {
		this.stuGrade = stuGrade;
	}
	@Override
	public int compareTo(Object o) {
		StudentDemo stu = (StudentDemo)o;
		if (this.stuGrade == stu.stuGrade) {
			return 0;
		}else if (this.stuGrade < stu.stuGrade) {
			return 1;
		}else {
			return -1;
		}
	}
}

MapDemo.java

package com.listSetMapCollection.practice;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

	/**
	 * Map集合的使用
	 * Map：键值对key-value
	 * @author Administrator
	 *
	 */
public class MapDemo {

	public static void main(String[] args) {
		Map<Integer,StudentDemo> stuMap = new HashMap<>();
		StudentDemo student1 = new StudentDemo("宋小宝","20140163",90);
		StudentDemo student2 = new StudentDemo("赵本山","20140235",85);
		StudentDemo student3 = new StudentDemo("黄晓明","20140196",80);
		StudentDemo student4 = new StudentDemo("张一山","20140345",86);
		StudentDemo student5 = new StudentDemo("黄   磊","20140145",96);
		StudentDemo student6 = new StudentDemo("沙   溢","20140526",70);
		
		stuMap.put(1, student1);
		stuMap.put(2, student2);
		stuMap.put(3, student3);
		stuMap.put(4, student4);
		stuMap.put(5, student5);
		stuMap.put(6, student6);
		
		System.out.println("*****使用for循环遍历*******");
		for (Integer i : stuMap.keySet()) {
			System.out.println(+i+".姓名："+stuMap.get(i).getStuName()+"-学号："+stuMap.get(i).getStuId()+"-成绩："+stuMap.get(i).getStuGrade());
		}
		System.out.println("*****两种使用Iterator迭代器遍历集合*********");
		System.out.println("******1***********");
		Iterator it = stuMap.keySet().iterator();
		while (it.hasNext()) {
			Integer stuIt = (Integer)it.next();
			System.out.println(stuIt+".姓名："+stuMap.get(stuIt).getStuName()+"-学号："+stuMap.get(stuIt).getStuId()+"-成绩："+stuMap.get(stuIt).getStuGrade());
		}
		System.out.println("********2***********");
		Iterator<Map.Entry<Integer, StudentDemo>> iterator = stuMap.entrySet().iterator();
		while (iterator.hasNext()) {
			Map.Entry<Integer, StudentDemo> entry = iterator.next();
			System.out.println(entry.getKey()+".姓名："+entry.getValue().getStuName()+"-学号："+entry.getValue().getStuId()+"-成绩："+entry.getValue().getStuGrade());
		}
		System.out.println("********第三种***************");
		for (Map.Entry<Integer, StudentDemo> entry : stuMap.entrySet()) {
			System.out.println(entry.getKey()+".姓名："+entry.getValue().getStuName()+"-学号："+entry.getValue().getStuId()+"-成绩："+entry.getValue().getStuGrade());
		}
		System.out.println("***********第四种************");
		for (StudentDemo stDemo :stuMap.values()) {
			System.out.println("姓名："+stDemo.getStuName()+"-学号："+stDemo.getStuId()+"-成绩："+stDemo.getStuGrade());
		}
	}
}