学步园

package test;<br /> import java.io.Serializable;<br /> public class User implements Serializable {<br /> private static final long serialVersionUID = 1L;<br /> private String name;<br /> private int number;<br /> public User() {<br /> }<br /> public User(String name, int number) {<br /> this.name = name;<br /> this.number = number;<br /> }<br /> public void setName(String name) {<br /> this.name = name;<br /> }<br /> public void setNumber(int number) {<br /> this.number = number;<br /> }<br /> public String getName() {<br /> return name;<br /> }<br /> public int getNumber() {<br /> return number;<br /> }<br /> } 

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package test;<br /> import java.io.*;<br /> import java.util.*;<br /> public class ObjectStreamDemo1 {<br /> public static void main(String[] args) {<br /> User[] users = { new User("cater", 101), new User("justin", 102) };<br /> // 写入新文件<br /> writeObjectsToFile(users, "D://FileStreamDemo1.txt");<br /> try {<br /> // 读取文件数据<br /> users = readObjectsFromFile("D://FileStreamDemo1.txt");<br /> // 显示读回的对象<br /> for (User user : users) {<br /> System.out.printf("%s/t%d%n", user.getName(), user.getNumber());<br /> }<br /> System.out.println();<br /> users = new User[2];<br /> users[0] = new User("momor", 103);<br /> users[1] = new User("becky", 104);<br /> // 附加新对象至文件<br /> appendObjectsToFile(users, "D://FileStreamDemo1.txt");<br /> // 读取文件数据<br /> users = readObjectsFromFile("D://FileStreamDemo1.txt");<br /> // 显示读回的对象<br /> for (User user : users) {<br /> System.out.printf("%s/t%d%n", user.getName(), user.getNumber());<br /> }<br /> }catch (ArrayIndexOutOfBoundsException e) {<br /> System.out.println("没有指定文件名!");<br /> }catch (FileNotFoundException e) {<br /> e.printStackTrace();<br /> }<br /> }<br /> // 将指定的对象写入至指定的文件<br /> public static void writeObjectsToFile(Object[] objs, String filename) {<br /> File file = new File(filename);<br /> try {<br /> ObjectOutputStream objOutputStream =<br /> new ObjectOutputStream(new FileOutputStream(file));<br /> for (Object obj : objs) {<br /> // 将对象写入文件<br /> objOutputStream.writeObject(obj);<br /> }<br /> // 关闭流<br /> objOutputStream.close();<br /> }catch (IOException e) {<br /> e.printStackTrace();<br /> }<br /> }<br /> // 将指定文件中的对象数据读回<br /> public static User[] readObjectsFromFile(String filename)<br /> throws FileNotFoundException {<br /> File file = new File(filename);<br /> // 如果文件不存在就丢出异常<br /> if (!file.exists()){<br /> throw new FileNotFoundException();<br /> }<br /> // 使用List先存储读回的对象<br /> List<User> list = new ArrayList<User>();<br /> try {<br /> FileInputStream fileInputStream = new FileInputStream(file);<br /> ObjectInputStream objInputStream = new ObjectInputStream(<br /> fileInputStream);<br /> while (fileInputStream.available() > 0) {<br /> list.add((User)objInputStream.readObject());<br /> }<br /> objInputStream.close();<br /> } catch (ClassNotFoundException e) {<br /> e.printStackTrace();<br /> } catch (IOException e) {<br /> e.printStackTrace();<br /> }<br /> User[] users = new User[list.size()];<br /> return list.toArray(users);<br /> }<br /> // 将对象附加至指定的文件之后<br /> public static void appendObjectsToFile(Object[] objs, String filename)<br /> throws FileNotFoundException {<br /> File file = new File(filename);<br /> // 如果文件不存在则丢出异常<br /> if (!file.exists())<br /> throw new FileNotFoundException();<br /> try {<br /> // 附加模式<br /> ObjectOutputStream objOutputStream = new ObjectOutputStream(<br /> new FileOutputStream(file, true)) {<br /> // 如果要附加对象至文件后<br /> // 必须重新定义这个方法<br /> protected void writeStreamHeader() throws IOException {<br /> }<br /> };<br /> for (Object obj : objs) {<br /> // 将对象写入文件<br /> objOutputStream.writeObject(obj);<br /> }<br /> objOutputStream.close();<br /> } catch (IOException e) {<br /> e.printStackTrace();<br /> }<br /> }<br /> }<br />

打印输出：

cater    101
justin    102

cater    101
justin    102
momor    103
becky    104