Java学习记录(补充六:集合框架补充)

 
collection工具类
package day11;
//工具类:提供一些静态的方法
import java.util.ArrayList;
import java.util.Collections;

public class CollectionsDemo {
    public static void main(String[] args) {
        ArrayList<Integer> list =new ArrayList<Integer>();
        list.add(100);
        list.add(78);
        list.add(87);
        list.add(1);
        
        for(Integer n:list){
            System.out.println(n);
        }
        System.out.println("********************");
        System.out.println("asc sorted");
        //升序排列
        Collections.sort(list);
        for(Integer n1:list){
            System.out.println(n1);
        }
        
        System.out.println("*******************");
        
        //翻转排序(想要排序必须先升序)
        System.out.println("desc sorted");
        Collections.reverse(list);
        for(Integer n2:list){
            System.out.println(n2);
        }
        
        System.out.println("********************");
        
        ArrayList<String> stringSet = new ArrayList<String>();
        
        stringSet.add("Zeeb");
        stringSet.add("Tcp");
        stringSet.add("Http");
        stringSet.add("要吃饭了...");
        stringSet.add("七夕到了");
        
        for(String s:stringSet){
            System.out.println(s);
        }
        System.out.println("*******************");
        Collections.sort(stringSet);
        for(String s1:stringSet){
            System.out.println(s1);
        }
        
        
        
        
        
    }
}







公用News类
package day11;

public class News implements Comparable<News> {
    private String pubDate;
    private String title;

    public String getPubDate() {
        return pubDate;
    }

    public void setPubDate(String pubDate) {
        this.pubDate = pubDate;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public News(String pubDate, String title) {
        super();
        this.pubDate = pubDate;
        this.title = title;
    }

    public News() {
        super();
    }

    @Override
    public int compareTo(News o) {
        return this.pubDate.compareTo(o.pubDate);
    }

}






练习1(ArrayList)
package day11;

import java.util.ArrayList;
import java.util.Collections;

public class ListDemo {
    //(box)装箱:把基本数据类型转换为object类型(子类转换为父类)
    //(unBox)拆箱:把object类型转换为基本数据类型(父类转换为子类:强转)
    public static void main(String[] args) {
        ArrayList<News> newsList = new ArrayList<News>();
        News news1 = new News("2017-8-28","又到一年七夕日");
        News news2 = new News("2017-8-29","星期一,又要上课了");
        News news3 = new News("2017-8-27","开学了");
        
        newsList.add(news1);
        newsList.add(news2);
        newsList.add(news3);
        
        //newsList.add(news3);//可以重复,重复会显示
        
        Collections.sort(newsList);
        
        for(News news:newsList){
            System.out.println(news.getPubDate()+" "+news.getTitle());
        }
        System.out.println("delete first");
        
        newsList.remove(0);//索引值不能为最后一个,会报错
        
        //newsList.clear();//全部都删除
        
        for(News news:newsList){
            System.out.println(news.getPubDate()+" "+news.getTitle());
        }
        
    }
    
}




结果图:






练习2(HashSet)
package day11;

import java.util.HashSet;
import java.util.Iterator;

public class SetDemo {
     public static void main(String[] args) {
        HashSet<Topic>topics = new HashSet<Topic>();
        Topic topic1 = new Topic(1,"七夕你快乐吗?");
        Topic topic2 = new Topic(2,"上课你快乐吗?");
        Topic topic3 = new Topic(3,"写代码你快乐吗?");
        
        topics.add(topic1);
        topics.add(topic2);
        topics.add(topic3);
        topics.add(topic1);//不能重复,重复不会显示
        
        //topic1 = new Topic(1,"七夕我不快乐");
        //topics.add(topic1);//新建了一个内存空间
        
        topic1.setTitle("七夕我很快乐");
        topic1.setTopicId(6);
        topics.add(topic1);//不是根据内容来判定是否能重复,根据对象的内存地址
        
        Iterator<Topic> it = topics.iterator();
        while(it.hasNext()){
            System.out.println(it.next().getTitle());
        }
    }
}





结果图:





公用Book类
package day11;

public class Book {
    private String bookId;
    private String bookName;
    private String author;
    private String pubDate;
    public Book() {
        super();
    }
    public Book(String bookId, String bookName, String author, String pubDate) {
        super();
        this.bookId = bookId;
        this.bookName = bookName;
        this.author = author;
        this.pubDate = pubDate;
    }
    public String getBookId() {
        return bookId;
    }
    public void setBookId(String bookId) {
        this.bookId = bookId;
    }
    public String getBookName() {
        return bookName;
    }
    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
    public String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public String getPubDate() {
        return pubDate;
    }
    public void setPubDate(String pubDate) {
        this.pubDate = pubDate;
    }
    @Override
    public boolean equals(Object obj) {
        
        if(!(obj instanceof Book)){
            return false;
        }
        Book book = (Book)obj;
        
        return this.bookName.equals(book.bookName)&&
                this.author.equals(book.author)&&
                this.pubDate.equals(book.pubDate);
        //两个@Override用来判断不能重复
    }
    @Override
    public int hashCode() {
        return this.bookName.hashCode();//返回当前对象的哈希码
    }
    
    
    
    
}






package day11;

import java.util.HashSet;
import java.util.Set;

public class bookTest {

    private Set<Book> books;
    
    public bookTest(){
        books = new HashSet<Book>();
        Book book1 = new Book("b011","哈利波特","外国人","1996-10-18");
        Book book2 = new Book("b015","孔乙己","鲁迅","1937-7-7");
        Book book3 = new Book("b008","时间简史","霍金","1737-7-7");
        Book book4 = new Book("b002","死亡笔记","日本人","2007-1-7");
        books.add(book1);
        books.add(book2);
        books.add(book3);
        books.add(book4);
    }
    
    public void showBooks() {
        for(Book book:books){
            System.out.println(book.getBookId()+"	"+book.getBookName()+"	"+book.getAuthor()+"	"+book.getPubDate());
        }
    }
    
    public void addBook(Book book) {
        books.add(book);
    }
    
    public boolean contains(Book book){
        return books.contains(book);
    }
    
    public static void main(String[] args) {
        bookTest bTest = new bookTest();
        bTest.showBooks();
        
        System.out.println("-------------添加图书以后------------");
        
        Book book = new Book();
        book.setBookId("b007");
        book.setBookName("西游记");
        book.setAuthor("吴承恩");
        book.setPubDate("1592-3-3");
        
        bTest.addBook(book);
        
        Book book1 = new Book();
        book1.setBookId("b007");
        book1.setBookName("西游记");
        book1.setAuthor("吴承恩");
        book1.setPubDate("1592-3-3");
        
//        bTest.addBook(book1);
        
        boolean isContains = bTest.contains(book1);
        System.out.println(isContains);
        
        bTest.showBooks();
    }

}




结果图:







Job类
package day12homework;

public class Job implements Comparable<Job> {
    private int jobId;
    private String jobName;
    private String jobCatgory;
    private String jobPub_date;
    public Job() {
        super();
    }
    public Job(int jobId, String jobName, String jobCatgory, String jobPub_data) {
        super();
        this.jobId = jobId;
        this.jobName = jobName;
        this.jobCatgory = jobCatgory;
        this.jobPub_date = jobPub_data;
    }
    public int getJobId() {
        return jobId;
    }
    public void setJobId(int jobId) {
        this.jobId = jobId;
    }
    public String getJobName() {
        return jobName;
    }
    public void setJobName(String jobName) {
        this.jobName = jobName;
    }
    public String getJobCatgory() {
        return jobCatgory;
    }
    public void setJobCatgory(String jobCatgory) {
        this.jobCatgory = jobCatgory;
    }
    public String getJobPub_date() {
        return jobPub_date;
    }
    public void setJobPub_date(String jobPub_date) {
        this.jobPub_date = jobPub_date;
    }
    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Job)) {
            return false;
        }
        Job job = (Job)obj;
        return this.jobName.equals(job.jobName)
                &&this.jobCatgory.equals(job.jobCatgory)
                    &&this.jobPub_date.equals(job.jobPub_date);

    }
    public int hashCode() {
        return this.jobName.hashCode();
    }
    @Override
    public int compareTo(Job o) {
        if (this.jobId > o.jobId) {
            return 1;
        }else if (this.jobId == o.jobId) {
            return 0;
        }else {
            return -1;
        }
    }

}






Nmae选择器
package day12homework;

import java.text.Collator;
import java.util.Comparator;
import java.util.Locale;

public class JobComparatorByName implements Comparator<Job> {

    @Override
    public int compare(Job o1, Job o2) {
        Collator instance = Collator.getInstance(Locale.CHINA);
        return instance.compare(o1.getJobName(), o2.getJobName());
        //return o1.getJobName().compareTo(o2.getJobName());
    }

}






Pub_date选择器
package day12homework;

import java.util.Comparator;

public class JobComparatorByPub_date implements Comparator<Job> {

    @Override
    public int compare(Job o1, Job o2) {
        return o1.getJobPub_date().compareTo(o2.getJobPub_date());
    }

}






实现测试类
package day12homework;

import java.util.HashSet;

public class Test1 {
    private HashSet<Job> jobs;
    public Test1(){
        jobs=new HashSet<Job>();
        Job job1=new Job(5,"程序员","技术开发","2017-8-29");
        Job job2=new Job(15,"架构师","技术开发","2017-6-29");
        Job job3=new Job(55,"鼓励师","后勤","2017-2-25");
        Job job4=new Job(2,"保洁","后勤","2017-12-29");
        Job job5=new Job(9,"会计","财会","2016-8-29");
        jobs.add(job1);
        jobs.add(job2);
        jobs.add(job3);
        jobs.add(job4);
        jobs.add(job5);
    }
    public void showJobs(){
        for(Job job:jobs){
            System.out.println(job.getJobId()+"	"
                    +job.getJobName()+"	"
                    +job.getJobCatgory()+"	"
                    +job.getJobPub_date()+"	");
        }
    }
    
    public void addJob(Job job){
        this.jobs.add(job);
    }
    public void removeJob(Job job){
        this.jobs.remove(job);
    }
    public static void main(String[] args) {
        Test1 test1=new Test1();
        test1.showJobs();
        
        
        System.out.println("==========added===========");
        Job job1=new Job(19,"审计","审计","2016-8-19");
        test1.addJob(job1);
        test1.showJobs();
        
        System.out.println("=========deleted============");
        Job job2=new Job(19,"审计","审计","2016-8-19");
        test1.removeJob(job2);
        test1.showJobs();
    }

}




结果图:




package day12homework;

import java.util.HashMap;

public class Test3 {
    private HashMap<Job,Integer> jobs;
    public Test3(){
        jobs=new HashMap<Job,Integer>();
        Job job1=new Job(5,"程序员","技术开发","2017-8-29");
        Job job2=new Job(15,"架构师","技术开发","2017-6-29");
        Job job3=new Job(55,"鼓励师","后勤","2017-2-25");
        Job job4=new Job(2,"保洁","后勤","2017-12-29");
        Job job5=new Job(9,"会计","财会","2016-8-29");
        
        jobs.put(job1, 5);
        jobs.put(job2, 2);
        jobs.put(job3, 15);
        jobs.put(job4, 3);
        jobs.put(job5, 1);
    }
    
    public void updateNumber(Job job,int num){
        if(jobs.keySet().contains(job)){
            jobs.put(job, num);
        }
    }
    




结果图:






package day12homework;

import java.util.HashMap;

public class Test3 {
    private HashMap<Job,Integer> jobs;
    public Test3(){
        jobs=new HashMap<Job,Integer>();
        Job job1=new Job(5,"程序员","技术开发","2017-8-29");
        Job job2=new Job(15,"架构师","技术开发","2017-6-29");
        Job job3=new Job(55,"鼓励师","后勤","2017-2-25");
        Job job4=new Job(2,"保洁","后勤","2017-12-29");
        Job job5=new Job(9,"会计","财会","2016-8-29");
        
        jobs.put(job1, 5);
        jobs.put(job2, 2);
        jobs.put(job3, 15);
        jobs.put(job4, 3);
        jobs.put(job5, 1);
    }
    
    public void updateNumber(Job job,int num){
        if(jobs.keySet().contains(job)){
            jobs.put(job, num);
        }
    }
    
    public void showJobs(){
        for(Job job:jobs.keySet()){
            
            System.out.println(job.getJobId()+"	"
                    +job.getJobName()+"	"
                    +job.getJobCatgory()+"	"
                    +job.getJobPub_date()+"	"
                    +jobs.get(job).intValue());
        }
    }
    
    public static void main(String[] args) {
        Test3 test3=new Test3();
        test3.showJobs();
        
        System.out.println("=========修改数量以后============");
        //如果原集合并不存在此工作，则不修改
        Job job=new Job(55,"鼓励师1","后勤","2017-2-25");
        
        test3.updateNumber(job, 50);
        test3.showJobs();
        
    }

}




结果图:








        

	      

	    

	  

	  

	    
      
        【推广】
        免费学中医，健康全家人
      
	  

    

    

          原文地址：https://www.cnblogs.com/lizuowei/p/7444983.html