android数据存储之文件存储方法

概述文件存储是Android中最基本的一种数据存储方式，它不对存储的内容进行任何的格式化处理，所有数据都是原封不动的保存到文件当中的。

文件存储是 AndroID 中最基本的一种数据存储方式，它不对存储的内容进行任何的格式化处理，所有数据都是原封不动的保存到文件当中的。

概述

文件存取的核心就是输入流和输出流。

AndroID文件的 *** 作模式

文件的相关 *** 作方法

文件读写的实现

openfileOutput和openfileinput方法

 /**   * openfileOutput,openfileinput   * 这两种方法同sp一样只能讲文件保存到手机内存固定的路径中，   * 默认为 /data/data/<packagename>/files   */  private voID save2file() {    try {      //向文件写入内容      fileOutputStream os = openfileOutput("file.txt",Context.MODE_PRIVATE);      String text = "写数据到文件";      os.write(text.getBytes("utf-8"));      //关闭流      os.close();    } catch (fileNotFoundException e) {      e.printstacktrace();    } catch (UnsupportedEnCodingException e) {      e.printstacktrace();    } catch (IOException e) {      e.printstacktrace();    }  }  /**   *   */  private voID readfile() {    try {      fileinputStream ins = openfileinput("file.txt");      byte[] buffer = new byte[100];      int byteCount = ins.read(buffer);      String text = new String(buffer,byteCount,"utf-8");      Toast.makeText(this,text,Toast.LENGTH_SHORT).show();      ins.close();    } catch (fileNotFoundException e) {      e.printstacktrace();    } catch (IOException e) {      e.printstacktrace();    }  }

文件存储位置

/data/data/<package-name>/files目录下

openfileOutput和openfileinput方法可以获得 *** 作文件的OutputStream以及inputStream对象，而且可以通过流对象处理任何文件的数据，但是这两个方法同SharedPreferences一样，只能在手机内存卡的指定目录建立文件，因此在使用上仍然有一定的局限性。

读取SD卡上的文件

main_activity.xml:

<linearLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"  xmlns:tools="http://schemas.androID.com/tools"  androID:ID="@+ID/linearLayout1"  androID:layout_wIDth="match_parent"  androID:layout_height="match_parent"  androID:orIEntation="vertical"  tools:context="com.jay.example.filedemo2.MainActivity">  <TextVIEw    androID:layout_wIDth="wrap_content"    androID:layout_height="wrap_content"    androID:text="清输入文件名" />  <EditText    androID:ID="@+ID/editTitle"    androID:layout_wIDth="match_parent"    androID:layout_height="wrap_content"    androID:hint="文件名" />  <TextVIEw    androID:layout_wIDth="wrap_content"    androID:layout_height="wrap_content"    androID:text="清输入文件内容" />  <EditText    androID:ID="@+ID/editdetail"    androID:layout_wIDth="match_parent"    androID:layout_height="wrap_content"    androID:hint="文件内容" />  <button    androID:ID="@+ID/btnsave"    androID:layout_wIDth="wrap_content"    androID:layout_height="wrap_content"    androID:text="保存到SD卡" />  <button    androID:ID="@+ID/btnclean"    androID:layout_wIDth="wrap_content"    androID:layout_height="wrap_content"    androID:text="清空" />  <button    androID:ID="@+ID/btnread"    androID:layout_wIDth="wrap_content"    androID:layout_height="wrap_content"    androID:text="读取sd卡中的文件" /></linearLayout>

接着我们来写一个SD *** 作类： SDfileHelper.Java

public class SDfileHelper {  private Context context;  public SDfileHelper() {  }  public SDfileHelper(Context context) {    super();    this.context = context;  }  //往SD卡写入文件的方法  public voID savafileToSD(String filename,String filecontent) throws Exception {    //如果手机已插入sd卡,且app具有读写sd卡的权限    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {      filename = Environment.getExternalStorageDirectory().getCanonicalPath() + "/" + filename;      //这里就不要用openfileOutput了,那个是往手机内存中写数据的      fileOutputStream output = new fileOutputStream(filename);      output.write(filecontent.getBytes());      //将String字符串以字节流的形式写入到输出流中      output.close();      //关闭输出流    } else Toast.makeText(context,"SD卡不存在或者不可读写",Toast.LENGTH_SHORT).show();  }  //读取SD卡中文件的方法  //定义读取文件的方法:  public String readFromSD(String filename) throws IOException {    StringBuilder sb = new StringBuilder("");    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {      filename = Environment.getExternalStorageDirectory().getCanonicalPath() + "/" + filename;      //打开文件输入流      fileinputStream input = new fileinputStream(filename);      byte[] temp = new byte[1024];      int len = 0;      //读取文件内容:      while ((len = input.read(temp)) > 0) {        sb.append(new String(temp,len));      }      //关闭输入流      input.close();    }    return sb.toString();  }}

接着MainActivity.java实现相关逻辑：

public class MainActivity extends AppCompatActivity implements VIEw.OnClickListener{  private EditText editname;  private EditText editdetail;  private button btnsave;  private button btnclean;  private button btnread;  private Context mContext;  @OverrIDe  protected voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentVIEw(R.layout.activity_main);    mContext = getApplicationContext();    bindVIEws();  }  private voID bindVIEws() {    editname = (EditText) findVIEwByID(R.ID.editTitle);    editdetail = (EditText) findVIEwByID(R.ID.editdetail);    btnsave = (button) findVIEwByID(R.ID.btnsave);    btnclean = (button) findVIEwByID(R.ID.btnclean);    btnread = (button) findVIEwByID(R.ID.btnread);    btnsave.setonClickListener(this);    btnclean.setonClickListener(this);    btnread.setonClickListener(this);  }  @OverrIDe  public voID onClick(VIEw v) {    switch (v.getID()){      case R.ID.btnclean:        editdetail.setText("");        editname.setText("");        break;      case R.ID.btnsave:        String filename = editname.getText().toString();        String filedetail = editdetail.getText().toString();        SDfileHelper sdHelper = new SDfileHelper(mContext);        try        {          sdHelper.savafileToSD(filename,filedetail);          Toast.makeText(getApplicationContext(),"数据写入成功",Toast.LENGTH_SHORT).show();        }        catch(Exception e){          e.printstacktrace();          Toast.makeText(getApplicationContext(),"数据写入失败",Toast.LENGTH_SHORT).show();        }        break;      case R.ID.btnread:        String detail = "";        SDfileHelper sdHelper2 = new SDfileHelper(mContext);        try        {          String filename2 = editname.getText().toString();          detail = sdHelper2.readFromSD(filename2);        }        catch(IOException e){e.printstacktrace();}        Toast.makeText(getApplicationContext(),detail,Toast.LENGTH_SHORT).show();        break;    }  }}

最后别忘记在AndroIDManifest.xml写上读写SD卡的权限哦！

<!-- 在SDCard中创建与删除文件权限 --><uses-permission androID:name="androID.permission.MOUNT_UNMOUNT_fileSYstemS"/><!-- 往SDCard写入数据权限 --><uses-permission androID:name="androID.permission.WRITE_EXTERNAL_STORAGE"/>

如何判断虚拟和物理两种SDK

在默认情况下，会将一部分存储空间分给虚拟的SD卡使用（一部分用于安装AndroID *** 作系统）

androID.os.Enviroment.isExternalStorageRemovalbe()

返回true：SD卡是物理的，反之SD卡是虚拟的。

用于适配不同型号手机，反射获取SD卡路径和状态

package com.turing.base.activity.dataStore.fileStore;import androID.content.Context;import androID.os.Environment;import androID.os.StatFs;import androID.os.storage.StorageManager;import androID.text.TextUtils;import androID.util.Log;import java.io.file;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.concurrent.ConcurrentlinkedQueue;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * 用于适配不同型号手机，反射获取SD卡路径和状态 * */public class DevMountInfo {  private final String TAG = DevMountInfo.class.getSimplename();  private static final int ERROR = -1;  // class name  private final static String CLASS_name = "androID.os.storage.StorageVolume";  //remained spare memory size  private static final int REMAINED_SPARE_IN_MB = 100;  // method name  private final static String METHOD_GET_VolUME_List = "getVolumeList";  private final static String METHOD_GET_VolUME_STATE = "getVolumeState";  private final static String METHOD_IS_REMOVABLE = "isRemovable";  private final static String METHOD_GET_PATH = "getPath";  private final static String MOUNTED = "mounted";  private static DevMountInfo INSTANCE;  private String mSDCardpath = null;  // internal file path  private ConcurrentlinkedQueue<String> mInternalPathList = new ConcurrentlinkedQueue<String>();  // external file path  private ConcurrentlinkedQueue<String> mExternalPathList = new ConcurrentlinkedQueue<String>();  private ExecutorService mExecutor = null;  private DevMountInfo() {    mExecutor = Executors.newSingleThreadExecutor();  }  public static DevMountInfo getInstance() {    synchronized (DevMountInfo.class) {      if (null == INSTANCE) {        INSTANCE = new DevMountInfo();      }      return INSTANCE;    }  }  @OverrIDe  protected voID finalize() throws Throwable {    super.finalize();    synchronized (DevMountInfo.class) {      mInternalPathList.clear();      mExternalPathList.clear();      mExecutor.shutdown();      INSTANCE = null;    }  }  public voID init(final Context context) {    mExecutor.execute(new Runnable() {      @OverrIDe      public voID run() {        executeInit(context);      }    });  }  public boolean isSDCardFull() {    return REMAINED_SPARE_IN_MB > (getSDCardAvailSpace() * 1024);  }  public boolean isSDCardAvaiable() {    return !mExternalPathList.isEmpty() || !mInternalPathList.isEmpty();  }  public String getSDCardpath() {    return mSDCardpath;  }  public long getSDCardTotalSpace() {    long totalSpace = 0;    if (!TextUtils.isEmpty(mSDCardpath)) {      StatFs sf = new StatFs(mSDCardpath);      long blockSize = sf.getBlockSize();      long total = sf.getBlockCount();      totalSpace = total * blockSize / 1024;    }    return totalSpace;  }  public long getSDCardAvailSpace() {    long availSpace = 0;    if (!TextUtils.isEmpty(mSDCardpath)) {      StatFs sf = new StatFs(mSDCardpath);      long blockSize = sf.getBlockSize();      long availCount = sf.getAvailableBlocks();      availSpace = availCount * blockSize / 1024;    }    return availSpace;  }  public String getInternalSDCardpath() {    return mInternalPathList.peek();  }  public String getExternalSDCardpath() {    return mExternalPathList.peek();  }  private voID executeInit(Context context) {    StorageManager mStorageManager = (StorageManager) context.getSystemService(Context.STORAGE_SERVICE);    if (mStorageManager != null) {      Class<?> mStorageVolume = null;      Method mGetVolumeListMethod = null;      Method mGetVolumeStateMethod = null;      Method mGetPathMethod = null;      Method mIsRemovableMethod = null;      Object[] mStorageVolumeList = null;      try {        mStorageVolume = Class.forname(CLASS_name);        mGetVolumeListMethod = mStorageManager.getClass().getmethod(METHOD_GET_VolUME_List,new Class[0]);        mGetVolumeStateMethod = mStorageManager.getClass().getmethod(METHOD_GET_VolUME_STATE,new Class[]{String.class});        mIsRemovableMethod = mStorageVolume.getmethod(METHOD_IS_REMOVABLE,new Class[0]);        mGetPathMethod = mStorageVolume.getmethod(METHOD_GET_PATH,new Class[0]);        mStorageVolumeList = (Object[]) mGetVolumeListMethod.invoke(mStorageManager,new Object[0]);        boolean mIsRemovable = false;        if (mStorageVolumeList != null && mStorageVolumeList.length > 0) {          int mStorageVolumeCount = mStorageVolumeList.length;          Log.i(TAG,"init() === > StorageVolume Count = " + mStorageVolumeCount);          mInternalPathList.clear();          mExternalPathList.clear();          for (int i = 0; i < mStorageVolumeCount; ++i) {            String mStoragePath = (String) mGetPathMethod.invoke(mStorageVolumeList[i],new Object[0]);            mIsRemovable = ((Boolean) mIsRemovableMethod.invoke(mStorageVolumeList[i],new Object[0])).booleanValue();            if (!TextUtils.isEmpty(mStoragePath)) {              String state = (String) mGetVolumeStateMethod.invoke(mStorageManager,new Object[]{mStoragePath});              if ((state != null) && (state.equals(MOUNTED))) {                if (mIsRemovable) {                  Log.i(TAG,"init() === > external storage path = (" + mStoragePath + ")");                  mExternalPathList.add(mStoragePath);                } else {                  Log.i(TAG,"init() === > internal storage path = (" + mStoragePath + ")");                  mInternalPathList.add(mStoragePath);                }              }            }          }        }      } catch (ClassNotFoundException e) {        handleInvalID();        Log.e(TAG,"init() === > Exception:ClassNotFoundException");      } catch (NoSuchMethodException e) {        handleInvalID();        Log.e(TAG,"init() === > Exception:NoSuchMethodException");      } catch (IllegalArgumentException e) {        handleInvalID();        Log.e(TAG,"init() === > Exception:IllegalArgumentException");      } catch (illegalaccessexception e) {        handleInvalID();        Log.e(TAG,"init() === > Exception:illegalaccessexception");      } catch (InvocationTargetException e) {        handleInvalID();        Log.e(TAG,"init() === > Exception:InvocationTargetException");      }    } else {      handleInvalID();      Log.e(TAG,"init() === > can't get storage manager");    }    initSDCardpath();  }  private voID handleInvalID() {    mInternalPathList.add(Environment.getExternalStorageDirectory().getPath());  }  private voID initSDCardpath() {    if (!mExternalPathList.isEmpty()) {      mSDCardpath = mExternalPathList.peek();    } else if (!mInternalPathList.isEmpty()) {      mSDCardpath = mInternalPathList.peek();    } else {      mSDCardpath = Environment.getExternalStorageDirectory().getPath();    }    Log.i(TAG,"initSDCardpath() === > SDCARD PATH = (" + mSDCardpath + ")");  }  /**   * SDCARD是否存   */  public static boolean externalMemoryAvailable() {    return androID.os.Environment.getExternalStorageState().equals(        androID.os.Environment.MEDIA_MOUNTED);  }  /**   * 获取手机内部剩余存储空间   *   * @return   */  public static long getAvailableInternalMemorySize() {    file path = Environment.getDataDirectory();    StatFs stat = new StatFs(path.getPath());    long blockSize = stat.getBlockSize();    long availableBlocks = stat.getAvailableBlocks();    return availableBlocks * blockSize;  }  /**   * 获取手机内部总的存储空间   *   * @return   */  public static long getTotalinternalMemorySize() {    file path = Environment.getDataDirectory();    StatFs stat = new StatFs(path.getPath());    long blockSize = stat.getBlockSize();    long totalBlocks = stat.getBlockCount();    return totalBlocks * blockSize;  }  /**   * 获取手机内置存储剩余存储空间   *   * @return   */  public static long getAvailableInternalSystemMemorySize() {    file path = Environment.getRootDirectory();    StatFs stat = new StatFs(path.getPath());    long blockSize = stat.getBlockSize();    long availableBlocks = stat.getAvailableBlocks();    return availableBlocks * blockSize;  }  /**   * 获取手机内置存储总的存储空间   *   * @return   */  public static long getTotalinternalSystemMemorySize() {    file path = Environment.getRootDirectory();    StatFs stat = new StatFs(path.getPath());    long blockSize = stat.getBlockSize();    long totalBlocks = stat.getBlockCount();    return totalBlocks * blockSize;  }  /**   * 获取SDCARD剩余存储空间   *   * @return   */  public static long getAvailableExternalMemorySize() {    if (externalMemoryAvailable()) {      file path = Environment.getExternalStorageDirectory();      StatFs stat = new StatFs(path.getPath());      long blockSize = stat.getBlockSize();      long availableBlocks = stat.getAvailableBlocks();      return availableBlocks * blockSize;    } else {      return ERROR;    }  }  /**   * 获取SDCARD总的存储空间   *   * @return   */  public static long getTotalExternalMemorySize() {    if (externalMemoryAvailable()) {      file path = Environment.getExternalStorageDirectory();      StatFs stat = new StatFs(path.getPath());      long blockSize = stat.getBlockSize();      long totalBlocks = stat.getBlockCount();      return totalBlocks * blockSize;    } else {      return ERROR;    }  }  public static long getAvailableMemorySize(String path) {    if (null == path)      return 0;    StatFs stat = new StatFs(path);    long blockSize = stat.getBlockSize();    long availableBlocks = stat.getAvailableBlocks();    return availableBlocks * blockSize;  }}

读取raw和assets文件夹下的文件

相信大家对两个文件夹并不陌生，如果我们不想自己的文件被编译成二进制文件的话， 我们可以把文件放到这两个目录下，而两者的区别如下：

res/raw：文件会被映射到R.java文件中，访问的时候直接通过资源ID即可访问，而且 他不能有目录结构，就是不能再创建文件夹 assets：不会映射到R.java文件中，通过AssetManager来访问，能有目录结构，即， 可以自行创建文件夹。

读取文件资源：

res/raw：

inputStream is =getResources().openRawResource(R.raw.filename); 

assets：

AssetManager am = getAssets(); inputStream is = am.open("filename");

SAX引擎读取XML文件

sax引擎读取xml文件的原理：

sax技术在处理xml文件时并不一次性把xml文件装入内存，而是一边读一般解析。

使用sax处理xml需要一个Handler对象，一般会使用org.xml.sax.helpers.DefaultHandler的子类作为Handler对象

因此,这就需要处理如下5个分析点,也可称为分析事件:

开始分析xml文件。该分析点表示sax引擎刚开始处理xml文件，还没有读取xml文件中的内容。该分析点对应于DefaultHandler类中的startdocument()事件方法，可以在该方法中做一下初始化的工作！ 开始处理每一个xml元素，也就是遇到<product>，<item>这样的起始标记，sax引擎每次扫描到新的xml元素的起始标记会触发这个分析事件，对应的事件分析方法是startElement，在该方法中可以获取当前元素的名称和元素属性的相关信息 处理完一个xml元素，也就是遇到</product>，</item>这样的结束标记，该分析点对应的事件方法是endElement，在该事件中可以获得当前处理完的元素的全部信息。 处理完xml文件。如果sax引擎将整个xml文件的内容都扫描完了，就到了这个分析点，该分析点对应的事件方法enddocument()，该事件方法可能不是必需的，如果最后有以下收尾工作，如释放一下资源，可以在该方法中完成！ 读取字符分析点。这是最重要的分析点。如果没有这个分析点，前4步的处理相当于白跑一遍，虽然读取了xml文件中的所有内容，但并未保存这些内容，而这个分析点所对应的characters事件方法的主要作用就是保存sax引擎读取的xml文件中的内容。更准确地说是保存xml元素的文本，也就是<product>abc</product>中的abc。

Code

res\raw\product.xml

<?xml version="1.0" enCoding="utf-8"?><products>  <product>    <ID>10</ID>    <name>电脑</name>    <price>2067.25</price>  </product>  <product>    <ID>20</ID>    <name>微波炉</name>    <price>520</price>  </product>  <product>    <ID>30</ID>    <name>洗衣机</name>    <price>2400</price>  </product></products>

Product.java

public class Product{  private int ID;  private String name;  private float price;  public int getID()  {    return ID;  }  public voID setID(int ID)  {    this.ID = ID;  }  public String getname()  {    return name;  }  public voID setname(String name)  {    this.name = name;  }  public float getPrice()  {    return price;  }  public voID setPrice(float price)  {    this.price = price;  }}

XML2Product.java(DefaultHandler子类)

DefaultHandler子类 ，核心类，负责处理分析点事件。

import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;import java.util.ArrayList;import java.util.List;public class XML2Product extends DefaultHandler {  private List<Product> products;  private Product product;  private StringBuffer buffer = new StringBuffer();  public List<Product> getProducts() {    return products;  }  @OverrIDe  public voID characters(char[] ch,int start,int length)      throws SAXException {    buffer.append(ch,start,length);    super.characters(ch,length);  }  @OverrIDe  public voID startdocument() throws SAXException {    // 开始分析xml文件,创建List对象用于保存分析完的Product对象    products = new ArrayList<Product>();  }  @OverrIDe  public voID startElement(String uri,String localname,String qname,Attributes attributes) throws SAXException {    if (localname.equals("product")) {      // 如果分析的是<product>标签，则创建一个Product对象      product = new Product();    }    super.startElement(uri,localname,qname,attributes);  }  @OverrIDe  public voID endElement(String uri,String qname)      throws SAXException {    if (localname.equals("product")) {      // 处理完 <product>标签后 将product对象添加到products中      products.add(product);    } else if (localname.equals("ID")) {      // 设置ID属性的值      product.setID(Integer.parseInt(buffer.toString().trim()));      // 将标签内容的缓存区清空      buffer.setLength(0);    } else if (localname.equals("name")) {      product.setname(buffer.toString().trim());      buffer.setLength(0);    } else if (localname.equals("price")) {      product.setPrice(float.parsefloat(buffer.toString().trim()));      buffer.setLength(0);    }    super.endElement(uri,qname);  }}

Xml2JavaObjectAct

import androID.app.AlertDialog;import androID.os.Bundle;import androID.support.v7.app.AppCompatActivity;import androID.util.Xml;import androID.vIEw.VIEw;import com.turing.base.R;import java.io.inputStream;import java.util.List;public class Xml2JavaObjectAct extends AppCompatActivity {  @OverrIDe  protected voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentVIEw(R.layout.activity_xml2_java_object);  }  public voID onClick_XMLToObject(VIEw vIEw) {    try {      // 打开资源文件      inputStream is = getResources().openRawResource(R.raw.products);      XML2Product xml2Product = new XML2Product();      // 开始分析prIDucts.xml文件      androID.util.Xml.parse(is,Xml.EnCoding.UTF_8,xml2Product);      // 输出转换后的java对象      List<Product> products = xml2Product.getProducts();      String msg = "共" + products.size() + "个产品\n";      for (Product product : products) {        msg += "ID:" + product.getID() + " 产品名：" + product.getname()            + " 价格：" + product.getPrice() + "\n";      }      // d出对话框      new AlertDialog.Builder(this).setTitle("产品信息").setMessage(msg)          .setPositivebutton("关闭",null).show();    } catch (Exception e) {    }  }}

效果图

Code

activity_jar_zip.xml

<?xml version="1.0" enCoding="utf-8"?><linearLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"  androID:layout_wIDth="fill_parent"  androID:layout_height="fill_parent"  androID:orIEntation="vertical" >  <button    androID:layout_wIDth="fill_parent"    androID:layout_height="wrap_content"    androID:onClick="onClick_Jar_Compress"    androID:text="用jar格式压缩文件" />  <button    androID:layout_wIDth="fill_parent"    androID:layout_height="wrap_content"    androID:onClick="onClick_Jar_Uncompress"    androID:text="解压jar格式文件" />  <button    androID:layout_wIDth="fill_parent"    androID:layout_height="wrap_content"    androID:onClick="onClick_Zip_Compress"    androID:text="用zip格式压缩文件" />  <button    androID:layout_wIDth="fill_parent"    androID:layout_height="wrap_content"    androID:onClick="onClick_Zip_Uncompress"    androID:text="解压zip格式文件" /></linearLayout>

JarZipAct

import androID.os.Bundle;import androID.support.v7.app.AppCompatActivity;import androID.vIEw.VIEw;import androID.Widget.Toast;import com.turing.base.R;import java.io.file;import java.io.fileinputStream;import java.io.fileOutputStream;import java.io.inputStream;import java.util.jar.JarEntry;import java.util.jar.JarinputStream;import java.util.jar.JarOutputStream;import java.util.zip.ZipEntry;import java.util.zip.ZipinputStream;import java.util.zip.ZipOutputStream;public class JarZipAct extends AppCompatActivity {  @OverrIDe  protected voID onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentVIEw(R.layout.activity_jar_zip);  }  public voID onClick_Jar_Compress(VIEw vIEw) {    try {      // 使用fileOutputStream对象指定一个要输出的压缩文件(file.jar)      fileOutputStream fos = new fileOutputStream(          androID.os.Environment.getExternalStorageDirectory()              + "/file.jar");      // 第一步 创建JarOutputStream对象      JarOutputStream jos = new JarOutputStream(fos);      // 第二步 创建一个JarEntry对象，并指定待压缩文件在压缩包中的文件名      JarEntry jarEntry = new JarEntry("strings.xml");      jos.putNextEntry(jarEntry);      inputStream is = getResources().getAssets().open("strings.xml");      byte[] buffer = new byte[8192];      int count = 0;      // 第四步 写入数据      while ((count = is.read(buffer)) >= 0) {        jos.write(buffer,count);      }      // 第五步 关闭当前的JarEntry等对象      is.close();      jos.closeEntry();      jos.close();      Toast.makeText(this,"成功将strings.xml文件以jar格式压缩.",Toast.LENGTH_LONG)          .show();    } catch (Exception e) {      Toast.makeText(this,e.getMessage(),Toast.LENGTH_LONG).show();    }  }  public voID onClick_Jar_Uncompress(VIEw vIEw) {    try {      // 定义要解压的文件      String filename = androID.os.Environment          .getExternalStorageDirectory() + "/file.jar";      if (!new file(filename).exists()) {        Toast.makeText(this,"压缩文件不存在.",Toast.LENGTH_LONG).show();        return;      }      // 使用fileinputStream对象指定要解压的对象      fileinputStream fis = new fileinputStream(filename);      // 1 创建JarinputStream对象来读取压缩文件（file.jar）      JarinputStream jis = new JarinputStream(fis);      // 2 调用getNextJarEntry方法打开压缩包中的第一个文件 ，如果有多个，多次调用该方法      JarEntry jarEntry = jis.getNextJarEntry();      // 3 输出已解压的文件      fileOutputStream fos = new fileOutputStream(          androID.os.Environment.getExternalStorageDirectory()              + "/" + jarEntry.getname());      byte[] buffer = new byte[8192];      int count = 0;      // 4 输出已解压的字节流      while ((count = jis.read(buffer)) >= 0) {        fos.write(buffer,count);      }      // 5 关闭      jis.closeEntry();      jis.close();      fos.close();      Toast.makeText(this,"成功解压jar格式的文件.",Toast.LENGTH_LONG).show();    } catch (Exception e) {      Toast.makeText(this,Toast.LENGTH_LONG).show();    }  }  public voID onClick_Zip_Compress(VIEw vIEw) {    try {      // 指定了2个待压缩的w文件，都在assets目录中      String[] filenames = new String[]          {"main.xml","strings.xml"};      fileOutputStream fos = new fileOutputStream(          androID.os.Environment.getExternalStorageDirectory()              + "/file.zip");      ZipOutputStream zos = new ZipOutputStream(fos);      int i = 1;      //枚举filenames中的所有待压缩文件      while (i <= filenames.length) {        // 从filenames数组中取出当前待压缩的温佳明，作为压缩后的文件名,以保持要说前后文件名称一致        ZipEntry zipEntry = new ZipEntry(filenames[i - 1]);        // 打开当前的ZipEntry对象        zos.putNextEntry(zipEntry);        inputStream is = getResources().getAssets().open(            filenames[i - 1]);        byte[] buffer = new byte[8192];        int count = 0;        // 写入数据        while ((count = is.read(buffer)) >= 0) {          zos.write(buffer,count);        }        zos.flush();        // 关闭当前的ZipEntry对象        zos.closeEntry();        is.close();        i++;      }      zos.finish();      zos.close();      Toast.makeText(this,"成功将main.xml、strings.xml文件以zip格式压缩.",Toast.LENGTH_LONG).show();    }  }  public voID onClick_Zip_Uncompress(VIEw vIEw) {    try {      // 指定待解压的文件      String filename = androID.os.Environment          .getExternalStorageDirectory() + "/file.zip";      if (!new file(filename).exists()) {        Toast.makeText(this,Toast.LENGTH_LONG).show();        return;      }      fileinputStream fis = new fileinputStream(filename);      ZipinputStream zis = new ZipinputStream(fis);      ZipEntry zipEntry = null;      // 通过不断调用getNextEntry方法来解压file.zip中所有的文件      while ((zipEntry = zis.getNextEntry()) != null) {        fileOutputStream fos = new fileOutputStream(            androID.os.Environment.getExternalStorageDirectory()                + "/" + zipEntry.getname());        byte[] buffer = new byte[8192];        int count = 0;        while ((count = zis.read(buffer)) >= 0) {          fos.write(buffer,count);        }        zis.closeEntry();        fos.close();      }      zis.close();      Toast.makeText(this,Toast.LENGTH_LONG).show();    }  }}

原文链接：http://blog.csdn.net/yangshangwei/article/details/50831269

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