使用IO流写一个随机点名程序

前言

最近学习了关于IO流的一些知识点，但是应用还不够，所以今天做个简单案例：

随机创建名字导入文件中：

package ioandcollection;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Array;
import java.util.ArrayList;
import java.util.Random;

public class example02 {
    public static void main(String[] args) throws IOException{
        ArrayList<String> names = new ArrayList<>();
        String[] surnames = {"张", "王", "李", "赵", "刘", "陈", "杨", "黄", "周", "吴"};
        String[] maleNames = {"伟", "强", "磊", "军", "勇", "杰", "峰", "浩", "敏", "飞"};
        String[] femaleNames = {"芳", "娜", "婷", "秀", "霞", "敏", "莉", "红", "萍", "玲"};

        Random random = new Random();
        for (int i = 0; i < 15; i++) {
            String surname = surnames[random.nextInt(surnames.length)];
            String name;
            if (random.nextBoolean()) { // 随机选择男女
                name = maleNames[random.nextInt(maleNames.length)];
            } else {
                name = femaleNames[random.nextInt(femaleNames.length)];
            }
            names.add(surname + name);
        }
        writeName(names);
    }
    public static void writeName(ArrayList<String> names) throws IOException {
        String target = "filemould//students.txt";
        System.out.println(names);
        BufferedWriter wb = new BufferedWriter(new FileWriter(target));
        for (String name : names) {
            wb.write(name);
            wb.newLine();
            wb.flush();
        }
        wb.close();
    }
}

将名字导出存储在集合中，然后随机点名：

package ioandcollection;

import com.sun.xml.internal.ws.policy.privateutil.PolicyUtils;

import java.io.*;
import java.util.ArrayList;
import java.util.Random;

/*
* 需求：有一个文件里面存储了班级同学的姓名，每一个姓名占一行，要求通过程序实现随机点名器。
思路：
① 把文件中的数据读取到到集合中
② 使用Random产生一个随机数，获得随机索引。
③ 通过随机索引获取随机姓名
* */
public class example01 {
    public static void main(String[] args) throws IOException {
        ArrayList<String> list = new ArrayList<>();
        String content = "filemould\\students.txt";
        readFileContent(content,list);
        //产生一个随机数，获得随机索引
        Random random = new Random();
        int randomIndex = random.nextInt(list.size());

        //获取随机数姓名
        String randomName = list.get(randomIndex);
        System.out.println("被点到的同学是:" + randomName);
    }

    private static void readFileContent(String content,ArrayList<String> list) throws IOException {
        BufferedReader br = null;
        //创建文件字节缓冲输入流对象
        br = new BufferedReader(new FileReader(content));

        //一次读取一个字符
        String name;
        while((name = br.readLine())!=null){
            list.add(name);
        }
        System.out.println(list);
        br.close();
    }
}

总结：

1、wb.newLIne()可以将光标移动到下一行

2、br.readLine()可以读取下一行的内容