将学生信息保存到文件中，格式为.txt

运行成功可以直接搜索studen.txt,直接打开

代码如下

学生类

public class student  {
private String name;
private int age;
private double grade;
public student(String name,int age,double grade) {
	this.name=name;
	this.age=age;
	this.grade=grade;
}
public String getName() {
	return name;
}
public int getAge() {
	return age;
}
public double getGrade() {
	return grade;
}
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class studentclass {

	private List<student>stuList;
	private int size;
	
	public studentclass() {
		size=0;
		stuList=null;
	}
     public void createclass() {
    	 String names[]= {"张三","王五","李四","赵六","孙琦"};
    	 double grades[]= {89,90,78,85,73};
    	 int ages[]= {17,20,17,18,19};
    	 size=names.length;
    	 stuList=new ArrayList<student>();
    	 student temp;
    	 for(int i=0;i<size;i++) {
    		 temp=new student(names[i],ages[i],grades[i]);
    		 stuList.add(temp);
    	 }
     }
    
    public List<Map<String,String>>formatstudent(){
    	List fclass=new ArrayList<Map<String,String>>();
    	Map stu;
    	for(student s:stuList) {
    		stu=new HashMap<String,String>();
    		stu.put("姓名",s.getName());
    		stu.put("成绩",new Double(s.getGrade()).toString());
    		fclass.add(stu);
    	}
    	return fclass;
    }
}

import java.io.FileWriter;
import java.io.IOException;
import java.util.List;
import java.util.Map;

public class FileOperation {

		private FileWriter out;
		public FileOperation(String fileName)throws IOException{
			out=new FileWriter(fileName);
		}
		
		public void save(List<Map<String,String>>lst) throws IOException{
			for(Map<String,String>m:lst) {
				for(Map.Entry entry:m.entrySet()) {
					out.write(entry.getKey()+":"+entry.getValue()+"\t");
				}
				out.write("\r\n");
			}
		}
		public void close() throws IOException{
			out.close();
		}
	}

import java.io.IOException;
import java.util.List;
import java.util.Map;

public class test {

	public static void main(String[] args) {
		List<Map<String,String>>lst;
		
		studentclass xq=new studentclass();
		xq.createclass();
		lst=xq.formatstudent();
		try {
			FileOperation xqstudent=new FileOperation("student.txt");
			xqstudent.save(lst);
			xqstudent.close();
			System.out.println("文件保存成功！");
		}
  catch(IOException e) {
	  System.out.println("IO错误，文件保存失败！");
  }
	}
}