以二进制格式保存加载java对象

• 以二进制格式保存java对象为文件
• 加载保存的二进制文件，转为需要的对象

• 年级 Grade.java

package com.xzbd.demo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import java.io.Serializable;


@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class Grade implements Serializable {
    private String name;
    private String level;
}

• 学校 School.java

package com.xzbd.demo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import java.io.Serializable;
import java.util.List;


@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class School implements Serializable {
    private String name;
    private String address;
    private List gradeList;
}

• 工具类 IOUtil.java

package com.xzbd.demo;

import java.io.*;
import java.util.Objects;


public class IOUtil {

    
    public static void saveBinaryFileFromObject(String fullPath, Object obj) {
        ByteArrayOutputStream bos = null;
        ObjectOutputStream oos = null;
        try {
            bos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(bos);
            // 读取对象并转换成二进制数据
            oos.writeObject(obj);
            oos.flush();
            File destFile = new File(fullPath);
            if(!destFile.exists()){
                destFile.createNewFile();
            }
            bos.writeTo(new FileOutputStream(destFile));
            bos.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (oos != null) {
                try {
                    oos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    
    public static  T loadModelFromFile(String fileName, Class tClazz) {
        try {
            File file = new File(fileName);
            InputStream inStream = new FileInputStream(file);
            return loadModelFromStream(inStream, tClazz);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    
    public static  T loadModelFromStream(InputStream inStream, Class tClazz) {
        ObjectInputStream ois = null;
        try {
            ois = new ObjectInputStream(inStream);
            Object obj = ois.readObject();
            if (obj.getClass() == tClazz) {
                return (T) obj;
            } else {
                System.out.println("######### 加载文件转对象失败 #########");
                System.out.println("系统加载到的文件是：" + obj.getClass() + " 对象");
                System.out.println("您希望的对象是：" + tClazz + " 对象");
            }
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            if (Objects.nonNull(ois)) {
                try {
                    ois.close();
                    inStream.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        }
    }
}

• 测试类 Test.java

package com.xzbd.demo;

import java.util.ArrayList;
import java.util.List;


public class Test {

    public static void main(String[] args) {
        Grade grade1 = new Grade("一年级","1");
        Grade grade2 = new Grade("二年级","2");
        Grade grade3 = new Grade("三年级","3");
        Grade grade4 = new Grade("四年级","4");

        List gradeList = new ArrayList<>();
        gradeList.add(grade1);
        gradeList.add(grade2);
        gradeList.add(grade3);


        List gradeList2 = new ArrayList<>();
        gradeList2.add(grade2);
        gradeList2.add(grade3);
        gradeList2.add(grade4);

        School school = new School("小学","小学的地址",gradeList);
        School school2 = new School("大学","大学的地址",gradeList2);


        String file1 = "D:\z_tmp_data/school1";
        String file2 = "D:\z_tmp_data/school2";
        IOUtil.saveBinaryFileFromObject(file1,school);
        IOUtil.saveBinaryFileFromObject(file2,school2);

        School loadModelFromFile = IOUtil.loadModelFromFile(file1, School.class);
        School loadModelFromFile2 = IOUtil.loadModelFromFile(file2, School.class);

        System.out.println(loadModelFromFile.toString());
        System.out.println(loadModelFromFile2.toString());

    }
}

• 输出的文件
  

• 加载回的数据，打印
  

• lombok