概述

文件存取的核心就是輸入流和輸出流。

Android文件的操作模式

文件的相關(guān)操作方法

文件讀寫的實(shí)現(xiàn)

openFileOutput和openFileInput方法

/*** openFIleOutput ,openFileInput* 這兩種方法同sp一樣只能講文件保存到手機(jī)內(nèi)存固定的路徑中，* 默認(rèn)為 /data/data/<packageName>/files*/private void save2File() {try {//向文件寫入內(nèi)容FileOutputStream os = openFileOutput("file.txt", Context.MODE_PRIVATE);String text = "寫數(shù)據(jù)到文件";os.write(text.getBytes("utf-8"));//關(guān)閉流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,0,byteCount,"utf-8");Toast.makeText(this,text,Toast.LENGTH_SHORT).show();ins.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}

文件存儲(chǔ)位置

/data/data/<package-name>/files目錄下

openFileOutput和openFileInput方法可以獲得操作文件的OutputStream以及InputStream對(duì)象，而且可以通過(guò)流對(duì)象處理任何文件的數(shù)據(jù)，但是這兩個(gè)方法同SharedPreferences一樣，只能在手機(jī)內(nèi)存卡的指定目錄建立文件，因此在使用上仍然有一定的局限性。

讀取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"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="清輸入文件名" /><EditTextandroid:id="@+id/edittitle"android:layout_width="match_parent"android:layout_height="wrap_content"android:hint="文件名" /><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="清輸入文件內(nèi)容" /><EditTextandroid:id="@+id/editdetail"android:layout_width="match_parent"android:layout_height="wrap_content"android:hint="文件內(nèi)容" /><Buttonandroid:id="@+id/btnsave"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="保存到SD卡" /><Buttonandroid:id="@+id/btnclean"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="清空" /><Buttonandroid:id="@+id/btnread"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="讀取sd卡中的文件" /></LinearLayout>

接著我們來(lái)寫一個(gè)SD操作類： SDFileHelper.java

public class SDFileHelper {private Context context;public SDFileHelper() {}public SDFileHelper(Context context) {super();this.context = context;}//往SD卡寫入文件的方法public void savaFileToSD(String filename, String filecontent) throws Exception {//如果手機(jī)已插入sd卡,且app具有讀寫sd卡的權(quán)限if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {filename = Environment.getExternalStorageDirectory().getCanonicalPath() + "/" + filename;//這里就不要用openFileOutput了,那個(gè)是往手機(jī)內(nèi)存中寫數(shù)據(jù)的FileOutputStream output = new FileOutputStream(filename);output.write(filecontent.getBytes());//將String字符串以字節(jié)流的形式寫入到輸出流中output.close();//關(guān)閉輸出流} else Toast.makeText(context, "SD卡不存在或者不可讀寫", Toast.LENGTH_SHORT).show();}//讀取SD卡中文件的方法//定義讀取文件的方法:public String readFromSD(String filename) throws IOException {StringBuilder sb = new StringBuilder("");if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {filename = Environment.getExternalStorageDirectory().getCanonicalPath() + "/" + filename;//打開文件輸入流FileInputStream input = new FileInputStream(filename);byte[] temp = new byte[1024];int len = 0;//讀取文件內(nèi)容:while ((len = input.read(temp)) > 0) {sb.append(new String(temp, 0, len));}//關(guān)閉輸入流input.close();}return sb.toString();}}

接著MainActivity.java實(shí)現(xiàn)相關(guān)邏輯：

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;@Overrideprotected 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);}@Overridepublic 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(), "數(shù)據(jù)寫入成功", Toast.LENGTH_SHORT).show();}catch(Exception e){e.printStackTrace();Toast.makeText(getApplicationContext(), "數(shù)據(jù)寫入失敗", 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;}} }

最后別忘記在AndroidManifest.xml寫上讀寫SD卡的權(quán)限哦！

<!-- 在SDCard中創(chuàng)建與刪除文件權(quán)限 --> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <!-- 往SDCard寫入數(shù)據(jù)權(quán)限 --> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

如何判斷虛擬和物理兩種SDK

在默認(rèn)情況下，會(huì)將一部分存儲(chǔ)空間分給虛擬的SD卡使用（一部分用于安裝Android操作系統(tǒng)）

android.os.Enviroment.isExternalStorageRemovalbe()

返回true：SD卡是物理的，反之SD卡是虛擬的。

用于適配不同型號(hào)手機(jī)，反射獲取SD卡路徑和狀態(tài)

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;/*** 用于適配不同型號(hào)手機(jī)，反射獲取SD卡路徑和狀態(tài)**/ public class DevMountInfo {private final String TAG = DevMountInfo.class.getSimpleName();private static final int ERROR = -1;// class nameprivate final static String CLASS_NAME = "android.os.storage.StorageVolume";//remained spare memory sizeprivate static final int REMAINED_SPARE_IN_MB = 100;// method nameprivate 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 pathprivate ConcurrentLinkedQueue<String> mInternalPathList = new ConcurrentLinkedQueue<String>();// external file pathprivate 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;}}@Overrideprotected 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() {@Overridepublic 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);}/*** 獲取手機(jī)內(nèi)部剩余存儲(chǔ)空間** @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;}/*** 獲取手機(jī)內(nèi)部總的存儲(chǔ)空間** @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;}/*** 獲取手機(jī)內(nèi)置存儲(chǔ)剩余存儲(chǔ)空間** @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;}/*** 獲取手機(jī)內(nèi)置存儲(chǔ)總的存儲(chǔ)空間** @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;}/*** 獲取SDCARD剩余存儲(chǔ)空間** @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;}}/*** 獲取SDCARD總的存儲(chǔ)空間** @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;}}

讀取raw和assets文件夾下的文件

相信大家對(duì)兩個(gè)文件夾并不陌生，如果我們不想自己的文件被編譯成二進(jìn)制文件的話， 我們可以把文件放到這兩個(gè)目錄下，而兩者的區(qū)別如下：

• res/raw：文件會(huì)被映射到R.java文件中，訪問(wèn)的時(shí)候直接通過(guò)資源ID即可訪問(wèn)，而且 他不能有目錄結(jié)構(gòu)，就是不能再創(chuàng)建文件夾
• assets：不會(huì)映射到R.java文件中，通過(guò)AssetManager來(lái)訪問(wèn)，能有目錄結(jié)構(gòu)，即， 可以自行創(chuàng)建文件夾。

讀取文件資源：

res/raw：

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

assets：

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

SAX引擎讀取XML文件

sax引擎讀取xml文件的原理：

sax技術(shù)在處理xml文件時(shí)并不一次性把xml文件裝入內(nèi)存，而是一邊讀一般解析。

使用sax處理xml需要一個(gè)Handler對(duì)象，一般會(huì)使用org.xml.sax.helpers.DefaultHandler的子類作為Handler對(duì)象

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因此,這就需要處理如下5個(gè)分析點(diǎn),也可稱為分析事件:

開始分析xml文件。該分析點(diǎn)表示sax引擎剛開始處理xml文件，還沒(méi)有讀取xml文件中的內(nèi)容。該分析點(diǎn)對(duì)應(yīng)于DefaultHandler類中的startDocument()事件方法，可以在該方法中做一下初始化的工作！

開始處理每一個(gè)xml元素，也就是遇到<product>，<item>這樣的起始標(biāo)記，sax引擎每次掃描到新的xml元素的起始標(biāo)記會(huì)觸發(fā)這個(gè)分析事件，對(duì)應(yīng)的事件分析方法是startElement，在該方法中可以獲取當(dāng)前元素的名稱和元素屬性的相關(guān)信息

處理完一個(gè)xml元素，也就是遇到</product>，</item>這樣的結(jié)束標(biāo)記，該分析點(diǎn)對(duì)應(yīng)的事件方法是endElement，在該事件中可以獲得當(dāng)前處理完的元素的全部信息。

處理完xml文件。如果sax引擎將整個(gè)xml文件的內(nèi)容都掃描完了，就到了這個(gè)分析點(diǎn)，該分析點(diǎn)對(duì)應(yīng)的事件方法endDocument()，該事件方法可能不是必需的，如果最后有以下收尾工作，如釋放一下資源，可以在該方法中完成！

讀取字符分析點(diǎn)。這是最重要的分析點(diǎn)。如果沒(méi)有這個(gè)分析點(diǎn)，前4步的處理相當(dāng)于白跑一遍，雖然讀取了xml文件中的所有內(nèi)容，但并未保存這些內(nèi)容，而這個(gè)分析點(diǎn)所對(duì)應(yīng)的characters事件方法的主要作用就是保存sax引擎讀取的xml文件中的內(nèi)容。更準(zhǔn)確地說(shuō)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>電腦</name><price>2067.25</price></product><product><id>20</id><name>微波爐</name><price>520</price></product><product><id>30</id><name>洗衣機(jī)</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子類)

DefaultHandler子類 ，核心類，負(fù)責(zé)處理分析點(diǎn)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;}@Overridepublic void characters(char[] ch, int start, int length)throws SAXException {buffer.append(ch, start, length);super.characters(ch, start, length);}@Overridepublic void startDocument() throws SAXException {// 開始分析xml文件,創(chuàng)建List對(duì)象用于保存分析完的Product對(duì)象products = new ArrayList<Product>();}@Overridepublic void startElement(String uri, String localName, String qName,Attributes attributes) throws SAXException {if (localName.equals("product")) {// 如果分析的是<product>標(biāo)簽，則創(chuàng)建一個(gè)Product對(duì)象product = new Product();}super.startElement(uri, localName, qName, attributes);}@Overridepublic void endElement(String uri, String localName, String qName)throws SAXException {if (localName.equals("product")) {// 處理完 <product>標(biāo)簽后 將product對(duì)象添加到products中products.add(product);} else if (localName.equals("id")) {// 設(shè)置id屬性的值product.setId(Integer.parseInt(buffer.toString().trim()));// 將標(biāo)簽內(nèi)容的緩存區(qū)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, localName, 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 {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_xml2_java_object);}public void onClick_XMLToObject(View view) {try {// 打開資源文件InputStream is = getResources().openRawResource(R.raw.products);XML2Product xml2Product = new XML2Product();// 開始分析priducts.xml文件android.util.Xml.parse(is, Xml.Encoding.UTF_8, xml2Product);// 輸出轉(zhuǎn)換后的java對(duì)象List<Product> products = xml2Product.getProducts();String msg = "共" + products.size() + "個(gè)產(chǎn)品\n";for (Product product : products) {msg += "id:" + product.getId() + " 產(chǎn)品名：" + product.getName()+ " 價(jià)格：" + product.getPrice() + "\n";}// 彈出對(duì)話框new AlertDialog.Builder(this).setTitle("產(chǎn)品信息").setMessage(msg).setPositiveButton("關(guān)閉", null).show();} catch (Exception e) {}} }

效果圖

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文件的壓縮（Jar，Zip）

效果圖

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格式壓縮文件" /><Button android:layout_width="fill_parent"android:layout_height="wrap_content"android:onClick="onClick_Jar_Uncompress"android:text="解壓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格式壓縮文件" /><Button android:layout_width="fill_parent"android:layout_height="wrap_content"android:onClick="onClick_Zip_Uncompress"android:text="解壓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 {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_jar_zip);}public void onClick_Jar_Compress(View view) {try {// 使用FileOutputStream對(duì)象指定一個(gè)要輸出的壓縮文件(file.jar)FileOutputStream fos = new FileOutputStream(android.os.Environment.getExternalStorageDirectory()+ "/file.jar");// 第一步 創(chuàng)建JarOutputStream對(duì)象JarOutputStream jos = new JarOutputStream(fos);// 第二步 創(chuàng)建一個(gè)JarEntry對(duì)象，并指定待壓縮文件在壓縮包中的文件名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 寫入數(shù)據(jù)while ((count = is.read(buffer)) >= 0) {jos.write(buffer, 0, count);}// 第五步 關(guān)閉當(dāng)前的JarEntry等對(duì)象is.close();jos.closeEntry();jos.close();Toast.makeText(this, "成功將strings.xml文件以jar格式壓縮.", Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();}}public void onClick_Jar_Uncompress(View view) {try {// 定義要解壓的文件String filename = android.os.Environment.getExternalStorageDirectory() + "/file.jar";if (!new File(filename).exists()) {Toast.makeText(this, "壓縮文件不存在.", Toast.LENGTH_LONG).show();return;}// 使用FileInputStream對(duì)象指定要解壓的對(duì)象FileInputStream fis = new FileInputStream(filename);// 1 創(chuàng)建JarInputStream對(duì)象來(lái)讀取壓縮文件（file.jar）JarInputStream jis = new JarInputStream(fis);// 2 調(diào)用getNextJarEntry方法打開壓縮包中的第一個(gè)文件 ，如果有多個(gè)，多次調(diào)用該方法JarEntry jarEntry = jis.getNextJarEntry();// 3 輸出已解壓的文件FileOutputStream fos = new FileOutputStream(android.os.Environment.getExternalStorageDirectory()+ "/" + jarEntry.getName());byte[] buffer = new byte[8192];int count = 0;// 4 輸出已解壓的字節(jié)流while ((count = jis.read(buffer)) >= 0) {fos.write(buffer, 0, count);}// 5 關(guān)閉jis.closeEntry();jis.close();fos.close();Toast.makeText(this, "成功解壓jar格式的文件.", Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();}}public void onClick_Zip_Compress(View view) {try {// 指定了2個(gè)待壓縮的w文件，都在assets目錄中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;//枚舉filenames中的所有待壓縮文件while (i <= filenames.length) {// 從filenames數(shù)組中取出當(dāng)前待壓縮的溫佳明，作為壓縮后的文件名,以保持要說(shuō)前后文件名稱一致ZipEntry zipEntry = new ZipEntry(filenames[i - 1]);// 打開當(dāng)前的ZipEntry對(duì)象zos.putNextEntry(zipEntry);InputStream is = getResources().getAssets().open(filenames[i - 1]);byte[] buffer = new byte[8192];int count = 0;// 寫入數(shù)據(jù)while ((count = is.read(buffer)) >= 0) {zos.write(buffer, 0, count);}zos.flush();// 關(guān)閉當(dāng)前的ZipEntry對(duì)象zos.closeEntry();is.close();i++;}zos.finish();zos.close();Toast.makeText(this, "成功將main.xml、strings.xml文件以zip格式壓縮.",Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();}}public void onClick_Zip_Uncompress(View view) {try {// 指定待解壓的文件String filename = android.os.Environment.getExternalStorageDirectory() + "/file.zip";if (!new File(filename).exists()) {Toast.makeText(this, "壓縮文件不存在.", Toast.LENGTH_LONG).show();return;}FileInputStream fis = new FileInputStream(filename);ZipInputStream zis = new ZipInputStream(fis);ZipEntry zipEntry = null;// 通過(guò)不斷調(diào)用getNextEntry方法來(lái)解壓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, 0, count);}zis.closeEntry();fos.close();}zis.close();Toast.makeText(this, "成功解壓jar格式的文件.", Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();}} }

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