java读取文件的时候，一直重复读取，无法读取正确内容

Question

问题遇到的现象和发生背景

我用java写了一个结构体，存放一些数据，并用txt文件存储，但在读取的时候出现问题，一直重复读取文件最后的内容

问题相关代码，请勿粘贴截图

这是结构体代码
class shuju{
private int grade = 0;

private String leixing,lianmeng,qiudui,qiuxing;


public shuju(){}

public shuju(String leixing, String lianmeng,String qiudui,String qiuxing, int grade){

    this.leixing = leixing;

    this.lianmeng = lianmeng;
    this.qiudui = qiudui;
    this.qiuxing = qiuxing;

    this.grade = grade;

}

public void setleixing(String leixing) { this.leixing = leixing; }
public void setlianmeng(String lianmeng) { this.lianmeng = lianmeng; }
public void setqiudui(String qiudui) { this.qiudui = qiudui; }
public void setqiuxing(String qiuxing) { this.qiuxing = qiuxing; }


public void setGrade(int grade) { this.grade = grade; }

public String getleixing() { return leixing; }
public String getlianmeng() { return lianmeng; }
public String getqiudui() { return qiudui; }
public String getqiuxing() { return qiuxing; }


public int getGrade() { return grade; }

}
public class 尝试1 {
private static final int INFINITE = 1000000000;// 对于该题相当于无穷大
private static shuju[] sj ;// 保存所有平台
public static void main(String[] args) throws IOException{

    Scanner sc1 = new Scanner(System.in);
    int n;
    int zz=1;
    n = sc1.nextInt();
    //到时候如果有问题看这里
    sj=new shuju[n+1];
    shuju s =new shuju();
    s.setGrade(1);
    String filePath = "D:/a/b";
    File dir = new File(filePath);
    // 一、检查放置文件的文件夹路径是否存在，不存在则创建
    if (!dir.exists()) {
        dir.mkdirs();// mkdirs创建多级目录
    }
    File checkFile = new File(filePath + "/filename.txt");
    FileWriter writer = null;

    //读取文件的地方
    // 1.创建文件对象
    File fromFile = new File("D:/a/b/filename.txt");
    // 2.创建字符输入流
    Reader reader = null;
    try {
        reader = new FileReader(fromFile);
        // 3.循环读取（打印）
        int content = reader.read();
        int t=0;
        while (content != -1) {
            char aaa=(char)content;
            String bb ="";
            bb=bb+aaa;
            if(aaa==' ')
            {
                t++;
                bb="";
            }
            if(t==1)
            {
                while(content != -1)
                {
                    content = reader.read();
                    aaa=(char)content;
                    if(aaa==' ')
                        break;
                    bb=bb+aaa;
                }
                s.setleixing(bb);
                //System.out.println(s.getleixing());

            }
            if(t==2)
            {
                while(content != -1)
                {
                    content = reader.read();
                    aaa=(char)content;
                    if(aaa==' ')
                        break;
                    bb=bb+aaa;
                }
                s.setlianmeng(bb);
               // System.out.println(s.getlianmeng());
            }
            if(t==3)
            {
                while(content != -1)
                {
                    content = reader.read();
                    aaa=(char)content;
                    if(aaa==' ')
                        break;
                    bb=bb+aaa;
                }
                s.setqiudui(bb);
               // System.out.println(s.getqiudui());
            }
            if(t==4)
            {
                while(content != -1)
                {
                    content = reader.read();
                    aaa=(char)content;
                    if(aaa==' ')
                        break;
                    bb=bb+aaa;
                }
                s.setqiuxing(bb);
                //System.out.println(s.getqiuxing());
                t=0;
                sj[zz]=s;

                System.out.println(zz);
                System.out.println(sj[zz].getleixing());
                System.out.println(sj[zz].getlianmeng());
                System.out.println(sj[zz].getqiudui());
                System.out.println(sj[zz].getqiuxing());
                zz++;

               // System.out.println(sj[zz-1].getqiuxing());
            }
            //System.out.println(bb);
            content = reader.read();
        }

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        // 4.关闭流
        try {
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //读取数据写入结构体，就这里读取的不是我想要的内容
    for(int j=1;j<zz;j++)
    {
        System.out.println(j);
        System.out.println(sj[j].getleixing());
        System.out.println(sj[j].getlianmeng());
        System.out.println(sj[j].getqiudui());
        System.out.println(sj[j].getqiuxing());
    }

}

运行结果及报错内容

这是我文件里的内容

我的解答思路和尝试过的方法

我想要达到的结果

我想能正确读取我文件里的内容

Answer 1

用BufferedReader对象，一行一行读取。
shuju类要序列化，最好是保存到List集合，最后用ObjectOutputStream保存List集合；然后用ObjectInputStream读取List集合，循环显示即可。