序列化
Serializable
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/edt_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Name"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintBottom_toTopOf="@+id/edt_age"
app:layout_constraintEnd_toStartOf="@+id/guideline3"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/edt_math"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Math"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintBottom_toTopOf="@+id/edt_english"
app:layout_constraintEnd_toEndOf="@+id/edt_name"
app:layout_constraintTop_toBottomOf="@+id/edt_age" />
<EditText
android:id="@+id/edt_english"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="English"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintBottom_toTopOf="@+id/edt_chinese"
app:layout_constraintEnd_toEndOf="@+id/edt_name"
app:layout_constraintTop_toBottomOf="@+id/edt_math" />
<EditText
android:id="@+id/edt_chinese"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Chinese"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintBottom_toTopOf="@+id/guideline2"
app:layout_constraintEnd_toEndOf="@+id/edt_name"
app:layout_constraintTop_toBottomOf="@+id/edt_english" />
<EditText
android:id="@+id/edt_age"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Age"
android:inputType="textPersonName"
android:minHeight="48dp"
app:layout_constraintBottom_toTopOf="@+id/edt_math"
app:layout_constraintEnd_toEndOf="@+id/edt_name"
app:layout_constraintTop_toBottomOf="@+id/edt_name" />
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.5" />
<androidx.constraintlayout.widget.Guideline
android:id="@+id/guideline3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.6" />
<TextView
android:id="@+id/tv_grade"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
app:layout_constraintBottom_toTopOf="@+id/btn_save"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/guideline3"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/btn_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="save"
app:layout_constraintBottom_toTopOf="@+id/btn_load"
app:layout_constraintEnd_toEndOf="@+id/tv_grade"
app:layout_constraintStart_toStartOf="@+id/tv_grade"
app:layout_constraintTop_toBottomOf="@+id/tv_grade" />
<Button
android:id="@+id/btn_load"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="load"
app:layout_constraintBottom_toTopOf="@+id/guideline2"
app:layout_constraintStart_toStartOf="@+id/btn_save"
app:layout_constraintTop_toBottomOf="@+id/btn_save" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.myserialization;
import java.io.Serializable;
public class Student implements Serializable {
// 用ide自动生成版本号。否则，类的结构变化后，数据就没了。
private static final long serialVersionUID = -7091411988309226703L;
private String name;
// private transient int age; // 设置该属性不参加序列化
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 static final long serialVersionUID = -3142893894209501048L;
private int Math;
private int English;
private int Chinese;
private String grade;
public Score(int math, int english, int chinese) {
Math = math;
English = english;
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) {
Math = math;
}
public int getEnglish() {
return English;
}
public void setEnglish(int english) {
English = english;
}
public int getChinese() {
return Chinese;
}
public void setChinese(int chinese) {
Chinese = chinese;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
}
package com.example.myserialization;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
public class MainActivity extends AppCompatActivity {
private EditText edt_name, edt_age, edt_math, edt_english, edt_chinese;
private Button btn_save, btn_load;
private TextView tv_grade;
public static final String FILE_NAME = "myfile.data";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edt_name = findViewById(R.id.edt_name);
edt_age = findViewById(R.id.edt_age);
edt_math = findViewById(R.id.edt_math);
edt_english = findViewById(R.id.edt_english);
edt_chinese = findViewById(R.id.edt_chinese);
btn_save = findViewById(R.id.btn_save);
btn_load = findViewById(R.id.btn_load);
tv_grade = findViewById(R.id.tv_grade);
btn_save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int math = Integer.parseInt(edt_math.getText().toString());
int english = Integer.parseInt(edt_english.getText().toString());
int chinese = Integer.parseInt(edt_chinese.getText().toString());
Score score = new Score(math, english, chinese);
String name = edt_name.getText().toString();
int age = Integer.parseInt(edt_age.getText().toString());
Student student = new Student(name, age, score);
try {
// 写入对应用来说是输出，从磁盘读取是输入
ObjectOutputStream objectOutputStream = new ObjectOutputStream(openFileOutput(FILE_NAME, MODE_PRIVATE));
objectOutputStream.writeObject(student);
objectOutputStream.flush(); // 清理缓冲区
objectOutputStream.close();
Toast.makeText(MainActivity.this, "存入成功", Toast.LENGTH_SHORT).show();
edt_name.getText().clear();
edt_age.getText().clear();
edt_english.getText().clear();
edt_math.getText().clear();
edt_chinese.getText().clear();
tv_grade.setText("-");
} catch (IOException e) {
e.printStackTrace();
}
}
});
btn_load.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
ObjectInputStream objectInputStream = new ObjectInputStream(openFileInput(FILE_NAME));
Student student = (Student) objectInputStream.readObject();
edt_name.setText(String.valueOf(student.getName()));
edt_age.setText(String.valueOf(student.getAge()));
edt_math.setText(String.valueOf(student.getScore().getMath()));
edt_english.setText(String.valueOf(student.getScore().getEnglish()));
edt_chinese.setText(String.valueOf(student.getScore().getChinese()));
tv_grade.setText(String.valueOf(student.getScore().getGrade()));
} catch (IOException | ClassNotFoundException e) {
e.printStackTrace();
}
}
});
}
}
Parcelable
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/edt_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Name"
android:inputType="textPersonName"
app:layout_constraintBottom_toTopOf="@+id/edt_age"
app:layout_constraintEnd_toEndOf="@+id/edt_age"
app:layout_constraintStart_toStartOf="@+id/edt_age"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/edt_age"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Age"
android:inputType="textPersonName"
app:layout_constraintBottom_toTopOf="@+id/edt_math"
app:layout_constraintEnd_toEndOf="@+id/edt_math"
app:layout_constraintStart_toStartOf="@+id/edt_math"
app:layout_constraintTop_toBottomOf="@+id/edt_name" />
<EditText
android:id="@+id/edt_math"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Math"
android:inputType="textPersonName"
app:layout_constraintBottom_toTopOf="@+id/edt_english"
app:layout_constraintEnd_toEndOf="@+id/edt_english"
app:layout_constraintStart_toStartOf="@+id/edt_english"
app:layout_constraintTop_toBottomOf="@+id/edt_age" />
<EditText
android:id="@+id/edt_english"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="English"
android:inputType="textPersonName"
app:layout_constraintBottom_toTopOf="@+id/button"
app:layout_constraintEnd_toEndOf="@+id/button"
app:layout_constraintStart_toStartOf="@+id/button"
app:layout_constraintTop_toBottomOf="@+id/edt_math" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/edt_english" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
</data>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity2">
<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Name"
android:textSize="34sp"
app:layout_constraintBottom_toTopOf="@+id/tv_age"
app:layout_constraintEnd_toEndOf="@+id/tv_age"
app:layout_constraintStart_toStartOf="@+id/tv_age"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/tv_age"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Age"
android:textSize="34sp"
app:layout_constraintBottom_toTopOf="@+id/tv_math"
app:layout_constraintEnd_toEndOf="@+id/tv_math"
app:layout_constraintStart_toStartOf="@+id/tv_math"
app:layout_constraintTop_toBottomOf="@+id/tv_name" />
<TextView
android:id="@+id/tv_math"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Math"
android:textSize="34sp"
app:layout_constraintBottom_toTopOf="@+id/tv_english"
app:layout_constraintEnd_toEndOf="@+id/tv_english"
app:layout_constraintStart_toStartOf="@+id/tv_english"
app:layout_constraintTop_toBottomOf="@+id/tv_age" />
<TextView
android:id="@+id/tv_english"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="English"
android:textSize="34sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tv_math" />
</androidx.constraintlayout.widget.ConstraintLayout>
</layout>
<activity
android:name=".MainActivity2"
android:process=":process2"
android:exported="true" />
package com.example.myserialization2;
import android.os.Parcel;
import android.os.Parcelable;
public class Student implements Parcelable {
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;
}
protected Student(Parcel in) {
name = in.readString();
age = in.readInt();
score = in.readParcelable(Score.class.getClassLoader());
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(name);
dest.writeInt(age);
dest.writeParcelable(score, flags);
}
@Override
public int describeContents() {
return 0;
}
public static final Creator<Student> CREATOR = new Creator<Student>() {
@Override
public Student createFromParcel(Parcel in) {
return new Student(in);
}
@Override
public Student[] newArray(int size) {
return new Student[size];
}
};
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 Parcelable {
private static final long serialVersionUID = -3142893894209501048L;
private int Math;
private int English;
public Score(int math, int english) {
Math = math;
English = english;
}
protected Score(Parcel in) {
Math = in.readInt();
English = in.readInt();
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(Math);
dest.writeInt(English);
}
@Override
public int describeContents() {
return 0;
}
public static final Creator<Score> CREATOR = new Creator<Score>() {
@Override
public Score createFromParcel(Parcel in) {
return new Score(in);
}
@Override
public Score[] newArray(int size) {
return new Score[size];
}
};
public int getMath() {
return Math;
}
public void setMath(int math) {
Math = math;
}
public int getEnglish() {
return English;
}
public void setEnglish(int english) {
English = english;
}
}
package com.example.myserialization2;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import com.example.myserialization2.databinding.ActivityMainBinding;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Log.d("wmj", "onCreate: " + android.os.Process.myPid());
// Log.d("wmj", "onCreate: " + Thread.currentThread().getId());
ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String name = binding.edtName.getText().toString();
int age = Integer.valueOf(binding.edtAge.getText().toString());
int math = Integer.valueOf(binding.edtMath.getText().toString());
int english = Integer.valueOf(binding.edtEnglish.getText().toString());
Student student = new Student(name, age, new Score(math, english));
Intent intent = new Intent(MainActivity.this, MainActivity2.class);
// intent.putExtra("student", student);
Bundle bundle = new Bundle();
bundle.putParcelable("student", student);
intent.putExtra("data", bundle);
startActivity(intent);
}
});
}
}
package com.example.myserialization2;
import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;
import android.content.Intent;
import android.os.Bundle;
import com.example.myserialization2.databinding.ActivityMain2Binding;
public class MainActivity2 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityMain2Binding binding = DataBindingUtil.setContentView(this, R.layout.activity_main2);
Intent intent = getIntent();
Bundle bundle = intent.getBundleExtra("data");
Student student = bundle.getParcelable("student");
binding.tvName.setText(student.getName());
binding.tvAge.setText(String.valueOf(student.getAge()));
binding.tvMath.setText(String.valueOf(student.getScore().getMath()));
binding.tvEnglish.setText(String.valueOf(student.getScore().getEnglish()));
}
}
Gson
implementation 'com.google.code.gson:gson:2.8.8'
- 属性前加@SerializedName("student_name")自定义序列化时的名称
Gson gson = new Gson();
// 单个对象
Student student1 = new Student("Tom", 20, new Score(100, 99, 98));
String jsonStr1 = gson.toJson(student1);
String jsonStr2 = "{\"age\":22,\"name\":\"Lili\",\"score\":{\"Chinese\":80,\"English\":97,\"Math\":100}}";
Student student2 = gson.fromJson(jsonStr2, Student.class);
// List
List<Student> list = new ArrayList<>();
list.add(student1);
list.add(student2);
String jsonList = gson.toJson(list);
String jsonList2 = "[{\"age\":20,\"name\":\"Tom\",\"score\":{\"Chinese\":98,\"English\":99,\"Math\":100}},{\"age\":22,\"name\":\"Lili\",\"score\":{\"Chinese\":80,\"English\":97,\"Math\":100}}]";
Type typeStudents = new TypeToken<List<Student>>(){}.getType();
list = gson.fromJson(jsonList2, typeStudents);
// 数组
Student[] students = {student1, student2};
String jsonStudents1 = gson.toJson(students);
String jsonStudents2 = "[{\"age\":20,\"name\":\"Tom\",\"score\":{\"Chinese\":98,\"English\":99,\"Math\":100}},{\"age\":22,\"name\":\"Lili\",\"score\":{\"Chinese\":80,\"English\":97,\"Math\":100}}]";
Student[] students2 = gson.fromJson(jsonStudents2, Student[].class);
