发现问题：
在测试Student类的静态字段是否可以被序列化时，如果在Test类main方法中先调用write(),再调用read()方法，静态字段schoolName可以被打印出来；但是如果先write()执行完程序，再把write（）注释掉，执行read()方法，静态字段schoolName值为null。
Student类：
package Object2;
import java.io.Serializable;
public class Student implements Serializable{
private String name;
private int age;
public static String schoolName; //学校名称
private transient String pwd; //属性的值将不再被序列化
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 String getPwd() {
return pwd;
public void setPwd(String pwd) {
this.pwd = pwd;
public Student(String name, int age, String pwd) {
super();
this.name = name;
this.age = age;
this.pwd = pwd;
public Student() {
super();
@Override
public String toString() {
return "Student[name=" + name + ", age=" + age + ", pwd=" + pwd + ",schoolName=" + schoolName + "]";
}
}
测试类：
package Object2;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class Test {
public static void main(String[] args) {
write();
read();
}
public static void write() {
ObjectOutputStream oos = null;
try {
oos = null;
oos = new ObjectOutputStream(new FileOutputStream("F:\\object2.txt"));
Student stu = new Student("hkj",19,"62536");
Student.schoolName = "中北大学";
oos.writeObject(stu);
} catch (FileNotFoundException e) {
// TODO Auto-generated
catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated
catch block
e.printStackTrace();
}finally {
if(oos!=null) {
try {
oos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public static void read() {
ObjectInputStream ois = null;
try {
ois = new ObjectInputStream(new FileInputStream("F:\\\\object2.txt"));
Student s = (Student)ois.readObject();
System.out.println(s);
} catch (FileNotFoundException e) {
// TODO Auto-generated
catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated
catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated
catch block
e.printStackTrace();
}finally {
if(ois!=null) {
try {
ois.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
问题截图：
问题原因：
1、write();read();同时执行时，先执行write() Student.schoolName = “中北大学”; 会在write()中加载Student类，并为schoolName进行赋值。而write();read();两个方法在同一线程中，再执行read();时打印出来schoolName的值并不属于被序列化的学生对象，所以会打印出具体的值。
2、先只执行一次write()，再只执行一次read(),两个方法并不属于同一个线程，在执行read()时Student stu = (Student)ois.readObject();是在read()中加载Student类，此时schoolName并未被赋值所以会是null。
修改代码：
public static void main(String[] args) {
//write();
read();
}
运行截图：
