Java 文件与流

package iostudent;
/**
 * 要求从控制台输入5条学生的信息并将这些信息写入到student.txt文件中
数据的格式：
100 tom   13456787656
101 jazz  13456787656
102 jazz  13456787656
103 jazz  13456787656
104 jazz  13456787656

发现类3：
学生类：ID  NAME  PHONE
功能类 ：writeFile() readFile() 
测试类:

使用哪些流：FileReader/FileWriter-----------结点流（效率低）
          BufferedReader/BufferedWriter-----------处理流（高效）
 */
public class Student {
	private String id;
	private String name;
	private String phone;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	
}

package iostudent;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class StudentMgr {

	public void WriteFile(List<Student> list, String fileName) {
		BufferedWriter bw = null;
		try {
			//fileName - 一个字符串，表示与系统有关的文件名。
			//true - 一个 boolean 值，如果为 true，则将数据写入文件末尾处，而不是写入文件开始处。
			bw = new BufferedWriter(new FileWriter(fileName));
			Iterator<Student> it = list.iterator();
			while (it.hasNext()) {
				//每遍历一次就会获取到一个Student对象
				Student student = it.next();
				//获取到Student对象的信息并且拼串：姓名 电话号
				String temp = student.getId()+" "+student.getName() + " " + student.getPhone();
				//将拼接好的字符串写入到bw所关联的目标文件中
				bw.write(temp);
				//换行
				bw.newLine();
			}bw.close();
		} catch (IOException e) {
			e.printStackTrace();
		} 
	}
	
	public List<Student> ReadFile(String fileName) {
		List<Student> list = new ArrayList<Student>();
		BufferedReader bd = null;
		try {
			bd = new BufferedReader(new FileReader(fileName));
			String temp;
			while ((temp = bd.readLine()) != null && temp.length() != 0) {
				String[] temp1 = temp.split(" ");
				Student s = new Student();
				s.setId(temp1[0]);
				s.setName(temp1[1]);
				s.setPhone(temp1[2]);
				list.add(s);
			}bd.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} 
		return list;
	}
}

package iostudent;


import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;

public class Test {

	public static void main(String[] args) {
		String fileName = "D:\\PhoneDirectory.txt";
		Scanner input = new Scanner(System.in);
		List<Student> list = new ArrayList<Student>();
		String temp;
		for (int i = 0; i < 3; i++) {
			Student stu = new Student();
			System.out.print("input id:");
			stu.setId(input.next());
			System.out.print("input name:");
			stu.setName(input.next());
			System.out.print("input phone:");
			stu.setPhone(input.next());
			list.add(stu);
		}

		StudentMgr mgr = new StudentMgr();
		mgr.WriteFile(list, fileName);
		List<Student> list2 = mgr.ReadFile(fileName);
		Iterator<Student> it = list2.iterator();
		while (it.hasNext()) {
			Student st = it.next();
			System.out.println(st.getId()+"\t" +st.getName() + "\t" + st.getPhone());
		}
	}
}