本节课程代码＋注释
来源：6-5 应用 Collections.sort() 实现 List 排序
梁XX
2016-01-31 13:02
在课后作业中，在生成字符的集合时有参考其它慕课同学的写法，借鉴了一个字符类型集合的字符添加方法，并灵活使用了参数列表，佩服。
贴出我的代码，有机会让别的童鞋看看，换位想一下，有机会一起交流。
package com.imooc.season3.CollectionDemo;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
import java.util.stream.IntStream;
/*
* 运用Collections.sort(List list)对集合中的元素进行排序
* public class Collections extends Object
* This class consists exclusively of static methods that operate on or return collections.
* ①对Integer类的list集进行排序
* ----10个随机整数，打印出排序前和排序后
*
* ②对String类的list集进行排序
* ----人手输入3个字符串，并打印出排序前和排序后
*
* ③作业，存储随机生成的String类的list集并对其进行排序
* ----创建List<String> str集合后，往其添加十条随机字符串
* ----每条字符串的长度控制为10以内的随机整数
* ----每条字符串都是随机生成的字符，字符可重复
* ----但字符串不可重复
*/
public class CollectionsDemo {
public void IntCollection(){
List<Integer> intList = new ArrayList<Integer>();
Integer tmpInt ;
for(int i=0;i<10;i++){
do{
Random randomInt =new Random();
//An instance of this class is used to generate a stream of pseudorandom numbers.
tmpInt = randomInt.nextInt(100);
//返回0-100以内的整数
System.out.println("将要添加整数"+tmpInt);
}while(intList.contains(tmpInt));
intList.add(tmpInt);
}
System.out.println(" ");
System.out.println("========排序前===========");
for(Integer tmpNo :intList){
System.out.println(tmpNo);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(intList);
//void方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(Integer tmpNo :intList){
System.out.println(tmpNo); }
}
public void StrCollection(){
List<String> strList = new ArrayList<String>();
System.out.println(" ");
System.out.println("========请输入3个字符串===========");
// quantity =input.nextInt();} //Scans the next token of the input as an int.
for(int i=1;i<=3;i++){
System.out.println("请输入第"+i+"个字符串");
Scanner input = new Scanner(System.in);
String inputStr =input.next();
if(strList.contains(inputStr)){ //如果为true
System.out.println("字符串"+inputStr+"已存在，请重新输入");
strList.remove(inputStr);
i--;
}
strList.add(inputStr);
}
System.out.println(" ");
System.out.println("========排序前===========");
for(String tmpName :strList){
System.out.println(tmpName);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(strList);
//void返回值的方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(String tmpName :strList){
System.out.println(tmpName); }
}
//生成字符表,借鉴一位慕课网童鞋的，对字符方面玩得真的很溜！！佩服
public void generateAlphabeta(List<Character> list,char st,char ed){
for(char c= st;c<=ed;c++){
list.add(c);
}
}
public void StrCollectionDemo(){
List<String> stringList = new ArrayList<String>();
List<Character> subList = new ArrayList<Character>();
generateAlphabeta(subList, 'a', 'z');//将a-z加入字符表
generateAlphabeta(subList, 'A', 'Z');//将A-Z加入字符表
generateAlphabeta(subList, '0', '9');//将0-9加入字符表
Random number = new Random();
int length;
for(int i=0;i<10;i++){
do{
length =number.nextInt(11);//规定1-10 的长度，返回一个1-10的其中一个数
}while(length ==0);
String tmpStr ="";
for(int y=0;y<length;y++){
Random index =new Random();
tmpStr =tmpStr+subList.get(index.nextInt(subList.size()));
}
stringList.add(tmpStr);
System.out.println("添加"+stringList.get(i)+"元素成功");
}
System.out.println(" ");
System.out.println("========排序前===========");
for(String tmpString :stringList){
System.out.println(tmpString);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(stringList);
//void返回值的方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(String tmpString :stringList){
System.out.println(tmpString ); }
}
public static void main(String[] args) {
// TODO Auto-generated method stub
CollectionsDemo t01 =new CollectionsDemo( );
t01.IntCollection();
//t01.StrCollection();
t01.StrCollectionDemo();
}
}
/*
* 运用Collections.sort(List list)对集合中的元素进行排序
* public class Collections extends Object
* This class consists exclusively of static methods that operate on or return collections.
* ①对Integer类的list集进行排序
* ----10个随机整数，打印出排序前和排序后
*
* ②对String类的list集进行排序
* ----人手输入3个字符串，并打印出排序前和排序后
*
* ③作业，存储随机生成的String类的list集并对其进行排序
* ----创建List<String> str集合后，往其添加十条随机字符串
* ----每条字符串的长度控制为10以内的随机整数
* ----每条字符串都是随机生成的字符，字符可重复
* ----但字符串不可重复
*/
public class CollectionsDemo {
public void IntCollection(){
List<Integer> intList = new ArrayList<Integer>();
Integer tmpInt ;
for(int i=0;i<10;i++){
do{
Random randomInt =new Random();
//An instance of this class is used to generate a stream of pseudorandom numbers.
tmpInt = randomInt.nextInt(100);
//返回0-100以内的整数
System.out.println("将要添加整数"+tmpInt);
}while(intList.contains(tmpInt));
intList.add(tmpInt);
}
System.out.println(" ");
System.out.println("========排序前===========");
for(Integer tmpNo :intList){
System.out.println(tmpNo);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(intList);
//void方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(Integer tmpNo :intList){
System.out.println(tmpNo); }
}
public void StrCollection(){
List<String> strList = new ArrayList<String>();
System.out.println(" ");
System.out.println("========请输入3个字符串===========");
// quantity =input.nextInt();} //Scans the next token of the input as an int.
for(int i=1;i<=3;i++){
System.out.println("请输入第"+i+"个字符串");
Scanner input = new Scanner(System.in);
String inputStr =input.next();
if(strList.contains(inputStr)){ //如果为true
System.out.println("字符串"+inputStr+"已存在，请重新输入");
strList.remove(inputStr);
i--;
}
strList.add(inputStr);
}
System.out.println(" ");
System.out.println("========排序前===========");
for(String tmpName :strList){
System.out.println(tmpName);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(strList);
//void返回值的方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(String tmpName :strList){
System.out.println(tmpName); }
}
//生成字符表,借鉴一位慕课网童鞋的，对字符方面玩得真的很溜！！佩服
public void generateAlphabeta(List<Character> list,char st,char ed){
for(char c= st;c<=ed;c++){
list.add(c);
}
}
public void StrCollectionDemo(){
List<String> stringList = new ArrayList<String>();
List<Character> subList = new ArrayList<Character>();
generateAlphabeta(subList, 'a', 'z');//将a-z加入字符表
generateAlphabeta(subList, 'A', 'Z');//将A-Z加入字符表
generateAlphabeta(subList, '0', '9');//将0-9加入字符表
Random number = new Random();
int length;
for(int i=0;i<10;i++){
do{
length =number.nextInt(11);//规定1-10 的长度，返回一个1-10的其中一个数
}while(length ==0);
String tmpStr ="";
for(int y=0;y<length;y++){
Random index =new Random();
tmpStr =tmpStr+subList.get(index.nextInt(subList.size()));
}
stringList.add(tmpStr);
System.out.println("添加"+stringList.get(i)+"元素成功");
}
System.out.println(" ");
System.out.println("========排序前===========");
for(String tmpString :stringList){
System.out.println(tmpString);
}
System.out.println(" ");
System.out.println("========排序后===========");
Collections.sort(stringList);
//void返回值的方法，Sorts the specified list into ascending order, according to the natural ordering of its elements.
for(String tmpString :stringList){
System.out.println(tmpString ); }
}
public static void main(String[] args) {
// TODO Auto-generated method stub
CollectionsDemo t01 =new CollectionsDemo( );
t01.IntCollection();
//t01.StrCollection();
t01.StrCollectionDemo();
}
}
////生成字符表
//public void generatorAlphabeta(List<Character> list,char st,char ed){
// for(char c= st;c<=ed;c++){
// list.add(c);
// }
// }
//
//public void testSort2(){
// List<String> stringList = new ArrayList<String>();
// List<Character> subList = new ArrayList<Character>();
//
// generatorAlphabeta(subList, 'a', 'z');//将a-z加入字符表
// generatorAlphabeta(subList, 'A', 'Z');//将A-Z加入字符表
// generatorAlphabeta(subList, '0', '9');//将0-9加入字符表
写回答
关注
1回答
-
- tzuhsin
- 2016-02-01 14:00:59
import java.util.stream.IntStream;
请问这是干嘛用的
Java入门第三季
Java中你必须懂得常用技能，不容错过的精彩，快来加入吧
409792 学习 · 4340 问题
相似问题