湖南省城乡建设厅网站,手机网站源码大全,网站建设项目招标文件,域名价格排行关于parcel#xff0c;我们先来讲讲它的“父辈” Serialize。 Serialize 是java提供的一套序列化机制。但是为什么要序列化#xff0c;怎么序列化#xff0c;序列化是怎么做到的#xff0c;我们将在本文探讨下。 一#xff1a;java 中的serialize 关于Serialize这个东东我们先来讲讲它的“父辈” Serialize。 Serialize 是java提供的一套序列化机制。但是为什么要序列化怎么序列化序列化是怎么做到的我们将在本文探讨下。 一java 中的serialize 关于Serialize这个东东think in java其实说的很详细大意如下 1.Serialize的目的 当你创建对象时你需要它一直存在但是当程序终止时它就消失了。 如果程序不运行的情况下可以保存某些信息这将非常有用。 如何我程序在下次运行的时候可以把上次运行的某些信息恢复回来. 2.Serialize的使用 使用一个嵌套的Serializable对象 package com.joyfulmath.androidstudy.bind.worm;import java.io.Serializable;public class Data implements Serializable {private int n;public Data(int n) {this.n n;}Overridepublic String toString() {return Integer.toString(n);}} package com.joyfulmath.androidstudy.bind.worm;import java.io.Serializable;
import java.util.Random;import com.joyfulmath.androidstudy.TraceLog;public class Worm implements Serializable {static Random rand new Random(47);Data[] d {new Data(rand.nextInt(10)),new Data(rand.nextInt(10)),new Data(rand.nextInt(10))};private Worm next;private char c;public Worm(int i, char x){TraceLog.i(Worm construct:i);c x;if(--i0){next new Worm(i,(char) (x1));}}public Worm(){TraceLog.i(default Worm construct);}Overridepublic String toString() {StringBuilder result new StringBuilder(:);result.append(c);result.append(();for(Data dat:d){result.append(dat );}result.append());if(next!null){result.append(next);}return result.toString();}} 验证序列化的读写 import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;import com.joyfulmath.androidstudy.TraceLog;public class WormSample {static final String path /mnt/sdcard/worm.out;public void doAction(){Worm w new Worm(6, a);TraceLog.i(\nw.toString());try {ObjectOutputStream opt new ObjectOutputStream(new FileOutputStream(path));opt.writeObject(Worm object\n);opt.writeObject(w);opt.close();ObjectInputStream in new ObjectInputStream(new FileInputStream(path));String s (String) in.readObject();Worm w2 (Worm) in.readObject();TraceLog.i(sw);} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}}
} 最后log 08-15 09:18:20.384: I/Worm(28437): init: Worm construct:6 [at (Worm.java:21)]
08-15 09:18:20.384: I/Worm(28437): init: Worm construct:5 [at (Worm.java:21)]
08-15 09:18:20.384: I/Worm(28437): init: Worm construct:4 [at (Worm.java:21)]
08-15 09:18:20.384: I/Worm(28437): init: Worm construct:3 [at (Worm.java:21)]
08-15 09:18:20.384: I/Worm(28437): init: Worm construct:2 [at (Worm.java:21)]
08-15 09:18:20.384: I/Worm(28437): init: Worm construct:1 [at (Worm.java:21)]
08-15 09:18:20.384: I/WormSample(28437): doAction:
08-15 09:18:20.384: I/WormSample(28437): :a(853):b(119):c(802):d(788):e(199):f(881) [at (WormSample.java:18)]
08-15 09:18:20.414: I/WormSample(28437): doAction: Worm object
08-15 09:18:20.414: I/WormSample(28437): :a(853):b(119):c(802):d(788):e(199):f(881) [at (WormSample.java:28)] 可以看到数据被很好的还原了包含内部的序列化对象 二parcel Serializable是java定义的一套序列化机制但是他是操作文件来执行的。或者说它的性能无法满足android上的要求 这样parcel被google发明出来用以取代Serializable。 1.Parcelable 的使用 package com.joyfulmath.androidstudy.bind.worm;import android.os.Parcel;
import android.os.Parcelable;public class DataP implements Parcelable {public int n;public DataP(int n) {this.n n;}Overridepublic int describeContents() {return 0;}Overridepublic void writeToParcel(Parcel dest, int flags) {dest.writeInt(n);}public static final Parcelable.CreatorDataP CREATOR new Parcelable.CreatorDataP() {public DataP createFromParcel(Parcel in) {return new DataP(in);}public DataP[] newArray(int size) {return new DataP[size];}};private DataP(Parcel in) {n in.readInt();}Overridepublic String toString() {return Integer.toString(n);}} package com.joyfulmath.androidstudy.bind.worm;import java.util.Random;import com.joyfulmath.androidstudy.TraceLog;import android.os.Parcel;
import android.os.Parcelable;public class WormP implements Parcelable {static Random rand new Random(47);public DataP[] d { new DataP(rand.nextInt(10)), new DataP(rand.nextInt(10)),new DataP(rand.nextInt(10)) };private WormP next;public byte c;public WormP(int i,byte x){TraceLog.i(Wormp construct:i);c x;if(--i0){next new WormP(i,(byte) (x1));}}Overridepublic int describeContents() {return 0;}Overridepublic void writeToParcel(Parcel dest, int flags) {dest.writeByte(c);dest.writeParcelableArray(d, 0);if (next ! null) {dest.writeParcelable(next, 0);}}public static final Parcelable.CreatorWormP CREATOR new Parcelable.CreatorWormP() {public WormP createFromParcel(Parcel in) {return new WormP(in);}public WormP[] newArray(int size) {return new WormP[size];}};private WormP(Parcel in) {c in.readByte();d (DataP[]) in.readParcelableArray(DataP.class.getClassLoader());}Overridepublic String toString() {StringBuilder result new StringBuilder(:);result.append(c);result.append(();for(DataP dat:d){result.append(dat );}result.append());if(next!null){result.append(next);}return result.toString();}
} parcel一般使用在intent的内容的传递所以本处做一个简单的模拟 public void doActionP(){TraceLog.i();byte a a;WormP w new WormP(6, a);TraceLog.i(w.toString());Intent intent new Intent();intent.putExtra(wormp, w);///...Intent newIntent new Intent(intent);WormP w2 newIntent.getParcelableExtra(wormp);TraceLog.i(w2.toString());TraceLog.i(end);} 08-15 10:14:11.924: I/WormSample(20183): doActionP: [at (WormSample.java:47)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:6 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:5 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:4 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:3 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:2 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormP(20183): init: Wormp construct:1 [at (WormP.java:21)]
08-15 10:14:11.934: I/WormSample(20183): doActionP: :97(8 5 3 ):98(1 1 9 ):99(8 0 2 ):100(7 8 8 ):101(1 9 9 ):102(8 8 1 ) [at (WormSample.java:50)]
08-15 10:14:11.934: I/WormSample(20183): doActionP: :97(8 5 3 ):98(1 1 9 ):99(8 0 2 ):100(7 8 8 ):101(1 9 9 ):102(8 8 1 ) [at (WormSample.java:59)]
08-15 10:14:11.934: I/WormSample(20183): doActionP: end [at (WormSample.java:61)] 可以看到结果数据完全正确。 以上就是parcel的使用方式在下一篇将探索parcel的实现方式。 参考 http://blog.csdn.net/niu_gao/article/details/6451699 转载于:https://www.cnblogs.com/deman/p/4742995.html
