开始有个Student的类
import java.util.*;
import java.io.*;
public class Job2Main {
static final String studentsFileName = "Student.txt";
/*
* 将List中的Student保存到Student.txt文件中
* 格式:
* 一个Student一行，行的格式如下
* 学号,姓名,年龄
* Student.txt示例
* 1,zhang3,20
* 2,Li4,20
* 3,Wang5,20
*/
void saveStudent(List<Student> students) throws Exception {
ObjectOutputStream fos=new ObjectOutputStream(new FileOutputStream(studentsFileName));
for(int i=0;i<students.size();i++){
Student s=students.get(i);
fos.writeObject(s);
}
fos.writeObject (null);
fos.close();
}
/*
* 读取Student.txt文件中的学生数据，每一行创建一个Student的对象，
* 多行数据便可以创建多个Student的对象，将这些对象保存到List中
* Student.txt示例
* 1,zhang3,20
* 2,Li4,20
* 3,Wang5,20
*/
List<Student> loadStudent() {
List<Student> stuList = new ArrayList<Student>();
studentsFileName.split(studentsFileName,stuList.size() );
int i1=Integer.parseInt(",");
if(stuList.size()>0){
for (int i = 0; i < stuList.size(); i++) {
Student s = (Student) stuList.get(i);
System.out.println(s);
}
}
else{
System.out.println("没有任何学生信息！");
}
return stuList;
} public static void main(String[] args) throws Exception {
Job2Main job2=new Job2Main();
Student s1=new Student(1, "zhang3", 20);
Student s2=new Student(2, "Li4", 20);
Student s3=new Student(3, "Wang5", 20);
List<Student> stuList=new ArrayList<Student>();
stuList.add(s1);
stuList.add(s2);
stuList.add(s3);
job2.saveStudent(stuList);
List<Student> students=job2.loadStudent();
for(Student s:students){
System.out.println(s);
}
}}
代码用两种方式写入文件,读出显式.import java.util.*;
import java.io.*;
public class Job2Main
{
static final String studentsFileName = "Student.dat"; //以对象方式写入文件。
static final String studentsTxtFileName = "Student.txt"; //文本方式写入文件。
/*
* 将List中的Student保存到Student.txt文件中
* 格式:
* 一个Student一行，行的格式如下
* 学号,姓名,年龄
* Student.txt示例
* 1,zhang3,20
* 2,Li4,20
* 3,Wang5,20
*/
//以对象方式写入文件
//
public void saveStudent(List<Student> students) throws Exception
{
ObjectOutputStream fos=new ObjectOutputStream(new FileOutputStream(studentsFileName));
for(int i=0;i<students.size();i++)
{
Student s=students.get(i);
fos.writeObject(s);
}
fos.writeObject (null);
fos.close();
}
//以文本方式写入文件
//
public void saveStudentInTxt(List<Student> students) throws Exception
{
BufferedWriter bw =new BufferedWriter(new FileWriter(studentsTxtFileName));
for(int i=0;i<students.size();i++)
{
Student s=students.get(i);
bw.write(s+"\r\n");
}
bw.flush();
bw.close();
} /*
* 读取Student.txt文件中的学生数据，每一行创建一个Student的对象，
* 多行数据便可以创建多个Student的对象，将这些对象保存到List中
* Student.txt示例
* 1,zhang3,20
* 2,Li4,20
* 3,Wang5,20
*/
//以对象方式读入
//
public List<Student> loadStudent(String file) throws Exception
{
List<Student> stuList = new ArrayList<Student>();
ObjectInputStream ois =new ObjectInputStream(new FileInputStream(file));
Student s;
while((s=(Student)ois.readObject())!=null)
{
stuList.add(s);
}
ois.close();
return stuList;
} //从文本文件读入，并放入对象，存入List.
//
public List<Student> loadStudentFromTxtFile(String file) throws Exception
{
List<Student> list =new ArrayList<Student>();
String temp=null; BufferedReader br =new BufferedReader(new FileReader(file));
while((temp=br.readLine())!=null)
{
String[] input= temp.split(",");
Student s=new Student();
s.setId(Integer.parseInt(input[0]));
s.setName(input[1]);
s.setAge(Integer.parseInt(input[2]));
list.add(s);
}
br.close();
return list;
} public static void main(String[] args) throws Exception
{
Job2Main job2=new Job2Main();
Student s1=new Student(1, "zhang3", 20);
Student s2=new Student(2, "Li4", 20);
Student s3=new Student(3, "Wang5", 20);
List<Student> stuList=new ArrayList<Student>();
stuList.add(s1);
stuList.add(s2);
stuList.add(s3);
job2.saveStudentInTxt(stuList); //以文本形式写入文件。
job2.saveStudent(stuList); //以对象的方式写入文件（不是文本文件）。 //job2.saveStudent(stuList);
//List<Student> students=job2.loadStudent();
List<Student> students= job2.loadStudentFromTxtFile(studentsTxtFileName); //以文本方式读入。
for(Student s:students)
{
System.out.println(s);
}
List<Student> students1= job2.loadStudent(studentsFileName); //以对象方式读入。
for(Student s:students1)
{
System.out.println(s);
}
}
}
class Student implements Serializable
{
private int id;
private String name;
private int age;
public Student()
{
}
public Student(int id,String name,int age)
{
this.id = id;
this.name = name;
this.age = age;
}
public void setName(String name)
{
this.name = name;
}
public String getName()
{
return name;
}
public void setId(int id)
{
this.id = id;
}
public int getId()
{
return id;
}
public void setAge(int age)
{
this.age= age;
}
public int getAge()
{
return age;
}
public boolean equals(Object o)
{
if(this==o)
{
return true;
}
if(o==null)
{
return false;
}
if(o instanceof Student)
{
Student other=(Student)o;
return this.id==other.getId() && this.name.equals(other.getName()) && this.age==other.getAge();
}
else
{
return false;
}
} public int hashCode()
{
return 13*id+17*age+name.hashCode();
} public String toString()
{
return id+","+name+","+age;
}
}