ObjectInputStream 和 ObjectOutputStream 的作用是，對基本數據和對象進行序列化操作支持。
創建“文件輸出流”對應的ObjectOutputStream對象，該ObjectOutputStream對象能提供對“基本數據或對象”的持久存儲；當我們需要讀取這些存儲的“基本數據或對象”時，可以創建“文件輸入流”對應的ObjectInputStream，進而讀取出這些“基本數據或對象”。
注意： 只有支持 java.io.Serializable 或 java.io.Externalizable 接口的對象才能被ObjectInputStream/ObjectOutputStream所操作！
ObjectOutputStream 函數列表
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// 構造函數ObjectOutputStream(OutputStream output)// public函數void close()void defaultWriteObject()void flush()ObjectOutputStream.PutField putFields()void reset()void useProtocolVersion(int version)void write(int value)void write(byte[] buffer, int offset, int length)void writeBoolean(boolean value)void writeByte(int value)void writeBytes(String value)void writeChar(int value)void writeChars(String value)void writeDouble(double value)void writeFields()void writeFloat(float value)void writeInt(int value)void writeLong(long value)final void writeObject(Object object)void writeShort(int value)void writeUTF(String value)void writeUnshared(Object object)ObjectInputStream 函數列表// 構造函數ObjectInputStream(InputStream input)int available()void close()void defaultReadObject()int read(byte[] buffer, int offset, int length)int read()boolean readBoolean()byte readByte()char readChar()double readDouble()ObjectInputStream.GetField readFields()float readFloat()void readFully(byte[] dst)void readFully(byte[] dst, int offset, int byteCount)int readInt()String readLine()long readLong()final Object readObject()short readShort()String readUTF()Object readUnshared()int readUnsignedByte()int readUnsignedShort()synchronized void registerValidation(ObjectInputValidation object, int priority)int skipBytes(int length) |
演示程序
源碼如下(ObjectStreamTest.java)：
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/** * ObjectInputStream 和 ObjectOutputStream 測試程序 * * 注意：通過ObjectInputStream, ObjectOutputStream操作的對象，必須是實現了Serializable或Externalizable序列化接口的類的實例。 * * */import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.Serializable; import java.util.Map;import java.util.HashMap;import java.util.Iterator;public class ObjectStreamTest { private static final String TMP_FILE = "box.tmp"; public static void main(String[] args) { testWrite(); testRead(); } /** * ObjectOutputStream 測試函數 */ private static void testWrite() { try { ObjectOutputStream out = new ObjectOutputStream( new FileOutputStream(TMP_FILE)); out.writeBoolean(true); out.writeByte((byte)65); out.writeChar('a'); out.writeInt(20131015); out.writeFloat(3.14F); out.writeDouble(1.414D); // 寫入HashMap對象 HashMap map = new HashMap(); map.put("one", "red"); map.put("two", "green"); map.put("three", "blue"); out.writeObject(map); // 寫入自定義的Box對象，Box實現了Serializable接口 Box box = new Box("desk", 80, 48); out.writeObject(box); out.close(); } catch (Exception ex) { ex.printStackTrace(); } } /** * ObjectInputStream 測試函數 */ private static void testRead() { try { ObjectInputStream in = new ObjectInputStream( new FileInputStream(TMP_FILE)); System.out.printf("boolean:%b\n" , in.readBoolean()); System.out.printf("byte:%d\n" , (in.readByte()&0xff)); System.out.printf("char:%c\n" , in.readChar()); System.out.printf("int:%d\n" , in.readInt()); System.out.printf("float:%f\n" , in.readFloat()); System.out.printf("double:%f\n" , in.readDouble()); // 讀取HashMap對象 HashMap map = (HashMap) in.readObject(); Iterator iter = map.entrySet().iterator(); while (iter.hasNext()) { Map.Entry entry = (Map.Entry)iter.next(); System.out.printf("%-6s -- %s\n" , entry.getKey(), entry.getValue()); } // 讀取Box對象，Box實現了Serializable接口 Box box = (Box) in.readObject(); System.out.println("box: " + box); in.close(); } catch (Exception e) { e.printStackTrace(); } }}class Box implements Serializable { private int width; private int height; private String name; public Box(String name, int width, int height) { this.name = name; this.width = width; this.height = height; } @Override public String toString() { return "["+name+": ("+width+", "+height+") ]"; }} |
運行結果：
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boolean:truebyte:65char:aint:20131015float:3.140000double:1.414000two -- greenone -- redthree -- bluebox: [desk: (80, 48) ] |
以上所述是小編給大家介紹的ObjectInputStream 和 ObjectOutputStream 的相關知識，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對服務器之家網站的支持！
