1.在读取文件中的内容时出现标题错误，Elective类已经继承Serializable接口
```package elective.system;
import java.io.File;
import java.io.Serializable;
import java.util.ArrayList;
/*
选修课程类
*/
public class Elective implements Serializable {
private int class_num; //选修课程编号
private String class_nature; //课程类别
private String class_name; //选修课名称
private String class_teacher; //课程教师
private int class_credit; //课程学分
private String class_time; //课程起止周
private String class_daily_time; //课程日常上课时间
private String class_school; //课程承办的二级学院
private int class_person_num; //课程人数
private String class_note; //课程备注
//无参构造方法
public Elective() {
}
//有参构造方法
public Elective(int class_num, String class_nature, String class_name, String class_teacher, int class_credit, String class_time, String class_daily_time, String class_school, int class_person_num, String class_note) {
this.class_num = class_num;
this.class_nature = class_nature;
this.class_name = class_name;
this.class_teacher = class_teacher;
this.class_credit = class_credit;
this.class_time = class_time;
this.class_daily_time = class_daily_time;
this.class_school = class_school;
this.class_person_num = class_person_num;
this.class_note = class_note;
}
//getter和setter方法
public int getClass_person_num() {
return class_person_num;
}
public void setClass_person_num(int class_person_num) {
this.class_person_num = class_person_num;
}
public int getClass_num() {
return class_num;
}
public void setClass_num(int class_num) {
this.class_num = class_num;
}
public String getClass_name() {
return class_name;
}
public void setClass_name(String class_name) {
this.class_name = class_name;
}
public String getClass_teacher() {
return class_teacher;
}
public void setClass_teacher(String class_teacher) {
this.class_teacher = class_teacher;
}
public int getClass_credit() {
return class_credit;
}
public void setClass_credit(int class_credit) {
this.class_credit = class_credit;
}
public String getClass_time() {
return class_time;
}
public void setClass_time(String class_time) {
this.class_time = class_time;
}
public String getClass_daily_time() {
return class_daily_time;
}
public void setClass_daily_time(String class_daily_time) {
this.class_daily_time = class_daily_time;
}
public String getClass_nature() {
return class_nature;
}
public void setClass_nature(String class_nature) {
this.class_nature = class_nature;
}
public String getClass_note() {
return class_note;
}
public void setClass_note(String class_note) {
this.class_note = class_note;
}
public String getClass_school() {
return class_school;
}
public void setClass_school(String class_school) {
this.class_school = class_school;
}
//增加选修课程
public boolean add_class(Elective elective){
boolean flag = false;
File file = new File("D:\\IdeaProjects\\basic-code\\01-code\\选修课程表\\class.txt");
OperateFile operateFile = new OperateFile();
try{
operateFile.save(elective,file);
flag = true;
}catch (Exception e){
e.printStackTrace();
}
return flag;
}
//查看已有选修课程
public ArrayList<Elective> look_class(){
ArrayList<Elective> list = new ArrayList<>();
File file = new File("D:\\IdeaProjects\\basic-code\\01-code\\选修课程表\\class.txt");
OperateFile operateFile = new OperateFile();
try{
list = operateFile.load(file);
}catch (Exception e){
e.printStackTrace();
}
return list;
}
@Override
public String toString() {
return "课程编号:" + class_num +
", 课程类别:" + class_nature +
", 课程名称:" + class_name +
", 授课教师:" + class_teacher +
", 学分:" + class_credit +
", 课程起止周:" + class_time +
", 课程上课时间:" + class_daily_time +
", 课程承办学院:" + class_school+
", 课程备注:" + class_note;
}
}
这是文件保存和读取类
package elective.system;
import java.io.*;
import java.util.ArrayList;
/*
文件操作类
*/
public class OperateFile implements Serializable{
public boolean save(Object e,File file) throws Exception{ // 保存对象
boolean flag = false ; // 定义操作标志位
FileOutputStream fos = new FileOutputStream(file,true); //采用追加方式写入数据
if(file.length()<1){
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(e);
flag = true;
oos.close();
}else{
MyObjectOutputStream mos = new MyObjectOutputStream(fos);
mos.writeObject(e);
flag = true;
mos.close();
}
return flag ;
}
public ArrayList load(File file) throws Exception{ // 读取对象
ArrayList<Object> list = new ArrayList();
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
while(fis.available()>0){
Object p = ois.readObject();
list.add(p);
}
ois.close();
return list;
}
}
class MyObjectOutputStream extends ObjectOutputStream{
public MyObjectOutputStream(OutputStream out) throws IOException {
super(out);
}
public void writeStreamHeader() throws IOException{
return;
}
}
这是操作：
Elective elective = new Elective();
ArrayList list = elective.look_class();
for(Elective et : list){
System.out.println(et.toString());
}
请问各位大佬这是为什么呢？
