ArrayList---File：集合数据写到文本文件/文本数据读取到集合中

• 把ArrayLit集合中的字符数据存储到文本内

package com.Brooke05;
/*
 * 把ArrayLit集合中的字符数据存储到文本内
 */
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;

public class ArrayListToFileTest {
    public static void main(String[] args) throws IOException {
        //创建集合对象
        ArrayList<String> array = new ArrayList<String>();

        //往集合中添加元素
        array.add("hello");
        array.add("world");
        array.add("java");

        //创建输出缓冲流对象
        BufferedWriter bw = new BufferedWriter(new FileWriter("ArrayListToFileTest.txt"));

        for(int i=0;i<array.size();i++) {
            String line = array.get(i);
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        //释放资源
        bw.close();
    }
}

• 读取文本数据存到集合中并遍历集合

package com.Brooke05;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

/*
 * 读取文本数据存到集合中并遍历集合
 */
public class FileToArrayListTest {
    public static void main(String[] args) throws IOException {
        //创建集合对象
        ArrayList<String> array = new ArrayList<String>();

        //创建输入缓冲流对象
        BufferedReader br = new BufferedReader(new FileReader("ArrayListToFileTest.txt"));

        String line;
        while((line = br.readLine()) != null) {
            array.add(line);
        }

        //释放资源
        br.close();

        for(int x=0;x<array.size();x++) {
            System.out.println(array.get(x));
        }
    }

}

• 键盘录入学生信息存入集合，遍历集合把学生信息存入文本(定义分割标记)

package com.Brooke05;
/*
 * 学生类
 */
public class Student {
    private String name;
    private String age;
    private String id;
    private String address;

    public Student() {

    }

    public Student(String name, String age, String id, String address) {
        this.name = name;
        this.age = age;
        this.id = id;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }




}

package com.Brooke05;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;

/*
 * 键盘录入学生信息存入集合，遍历集合把学生信息存入文本(定义分割标记)
 */
public class StudentTest {
    public static void main(String[] args) throws IOException {
        //创建结集合对象
        ArrayList<Student> array = new ArrayList<Student>();
        for(int x=0;x<3;x++) {
            addStudent(array);
        }

        //创建输出缓冲流对象
        BufferedWriter bw = new BufferedWriter(new FileWriter("StudentTest.txt"));

        for(int x=0;x<array.size();x++) {
//          String id = array.get(x).getId();
//          bw.write(id+",");
//          String name = array.get(x).getName();
//          bw.write(name+",");
//          String age = array.get(x).getAge();
//          bw.write(age+",");
//          String address = array.get(x).getAddress();
//          bw.write(address);
//          bw.newLine();

            Student stu = array.get(x);
            //链式编程
            StringBuilder sb = new StringBuilder();
            sb.append(stu.getId()).append(",").append(stu.getName()).append(",").append(stu.getAge()).append(",").append(stu.getAddress());
            bw.write(sb.toString());
            bw.newLine();
            bw.flush();
        }

        //释放资源
        bw.close();

    }

    //添加学生
    public static void addStudent(ArrayList<Student> array) {
        Scanner sc = new Scanner(System.in);
        String id = "";
        while(true) {
            System.out.println("请输入学号：");
            id = sc.nextLine();
            boolean flag = true;
            for(int x=0;x<array.size();x++) {
                if(id.equals(array.get(x).getId())) {
                    System.out.println("您输入的学号已经被占用，请重新输入！");
                    flag = false;
                }
            }
            if(flag == true) {
                break;
            }
        }
        System.out.println("请输入姓名：");
        String name = sc.nextLine();
        System.out.println("请输入年龄：");
        String age = sc.nextLine();
        System.out.println("请输入居住地：");
        String address = sc.nextLine();

        Student stu = new Student();
        stu.setId(id);
        stu.setName(name);
        stu.setAge(age);
        stu.setAddress(address);

        array.add(stu);
    }
}

• 把文本文件中的信息读取出来存储到集合中，最后遍历集合，在控制台输出

package com.Brooke05;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

/*
 * 把文本文件中的信息读取出来存储到集合中，最后遍历集合，在控制台输出
 */
public class StudentTest1 {
    public static void main(String[] args) throws IOException {
        //创建输入缓冲流对象
        BufferedReader br = new BufferedReader(new FileReader("StudentTest.txt"));

        //创建集合对象
        ArrayList<Student> array = new ArrayList<Student>();

        String line;
        while((line = br.readLine()) != null) {
            //分割字符串,分割后的元素存储到数组中,以","为分界点
            String[] strArray = line.split(",");
            Student stu = new Student();
            stu.setId(strArray[0]);
            stu.setName(strArray[1]);
            stu.setAge(strArray[2]);
            stu.setAddress(strArray[3]);

            array.add(stu);
        }

        //释放资源
        br.close();
        System.out.println("学号\t姓名\t年龄\t居住地");
        for(int x=0;x<array.size();x++) {
            Student stu = array.get(x);
            System.out.println(stu.getId()+"\t"+stu.getName()+"\t"+stu.getAge()+"\t"+stu.getAddress());
        }
    }
}