摘自：序列化与反序列化（1）Serializable —— Java原生态方法
作者：丶PURSUING
发布时间： 2021-05-08 19:20:21
网址：https://blog.csdn.net/weixin_44742824/article/details/116503261

//如果某个属性不需要序列化，可以添加关键字：transient
public class Student implements Serializable {private String name;private int age;private Score score;public Student(String name, int age, Score score) {this.name = name;this.age = age;this.score = score;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public Score getScore() {return score;}public void setScore(Score score) {this.score = score;}
}class Score implements Serializable{private int math;private int english;private int chinese;private String grade;public Score(int math, int english, int chinese) {this.math = math;this.english = english;this.chinese = chinese;if(math>=90 && english>=90 && chinese>=90){this.grade = "A";}else if(math>=80 && english>=80 && chinese>=80){this.grade = "B";}else {this.grade = "C";}}public int getMath() {return math;}public void setMath(int math) {this.math = math;}public int getEnglish() {return english;}public void setEnglish(int english) {this.english = english;}public int getChinese() {return chinese;}public void setChinese(int chinese) {this.chinese = chinese;}public String getGrade() {return grade;}
}
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MainActivity.java

public class MainActivity extends AppCompatActivity {EditText editTextName,editTextAge,editTextMath,editTextEnglish,editTextChinese;Button buttonSave,buttonLoad;TextView textViewGrade;//定义文件名为一个常量private static final String FILE_NAME = "myfile.data";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/*引入一个错误，观察try catch的机制int x = 5;//除以0是算数上的一个错误，应用程序会马上崩溃闪退try {x = x / 0;//  错误类型为算数错误}catch (ArithmeticException e){Log.e("calError", "onCreate: "+e);}*/editTextName = findViewById(R.id.name);editTextAge = findViewById(R.id.age);editTextMath = findViewById(R.id.math);editTextEnglish = findViewById(R.id.eng);editTextChinese = findViewById(R.id.chinese);buttonSave = findViewById(R.id.button);buttonLoad = findViewById(R.id.button2);//之前因为缺少这一句，导致对象没有实例化所以软件闪退textViewGrade = findViewById(R.id.textView);buttonSave.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {//点击保存后，创建变量，对象保存数据int math = Integer.valueOf(editTextMath.getText().toString());int english = Integer.valueOf(editTextEnglish.getText().toString());int chinese = Integer.valueOf(editTextChinese.getText().toString());Score score = new Score(math,english,chinese);String name = editTextName.getText().toString();int age = Integer.valueOf(editTextAge.getText().toString());Student student = new Student(name,age,score);try {//将对象序列化写入到文件中,借助下面这个接口，针对应用程序而言，是输出，输出到文件中//                                               第一个参数是文件的名称，第二个是读写的模式(这里选择覆盖)ObjectOutputStream objectOutputStream = new ObjectOutputStream(openFileOutput(FILE_NAME,MODE_PRIVATE));//把对象写入文件objectOutputStream.writeObject(student);objectOutputStream.flush();//清空缓冲区objectOutputStream.close();Toast.makeText(MainActivity.this,"data saved!",Toast.LENGTH_SHORT).show();//sava之后把页面数据清空用来呈现load的数据editTextChinese.getText().clear();editTextEnglish.getText().clear();editTextMath.getText().clear();editTextName.getText().clear();editTextAge.getText().clear();textViewGrade.setText("-");//抓住的错误类型为IOException}catch (IOException e){//这里不做其他处理，仅观察Log.e("IO", "IO error " , e);}}});//读取，反系列化buttonLoad.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {try {ObjectInputStream objectInputStream = new ObjectInputStream(openFileInput(FILE_NAME));//                类型强制转换为Student类Student student = (Student)objectInputStream.readObject();//对象重建显示在页面上editTextName.setText(student.getName());editTextAge.setText(String.valueOf(student.getAge()));editTextMath.setText(String.valueOf(student.getScore().getMath()));editTextEnglish.setText(String.valueOf(student.getScore().getEnglish()));editTextChinese.setText(String.valueOf(student.getScore().getChinese()));textViewGrade.setText(student.getScore().getGrade());} catch (IOException | ClassNotFoundException e) {Log.e("IO", "onClick: ", e);}}});}
}
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