android 读取文件内容操作

在Android系统中，这些文件保存在 /data/data/PACKAGE_NAME/files 目录下。

数据读取

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public static String read(Context context, String file) {
String data = "";
try {
FileInputStream stream = context.openFileInput(file);
StringBuffer sb = new StringBuffer();
int c;
while ((c = stream.read()) != -1) {
sb.append((char) c);
}
stream.close();
data = sb.toString();

} catch (FileNotFoundException e) {
} catch (IOException e) {
}
return data;
}
public static String read(Context context, String file) {
String data = "";
try {
FileInputStream stream = context.openFileInput(file);
StringBuffer sb = new StringBuffer();
int c;
while ((c = stream.read()) != -1) {
sb.append((char) c);
}
stream.close();
data = sb.toString();

} catch (FileNotFoundException e) {
} catch (IOException e) {
}
return data;
}

从代码上，看起来唯一的不同就是文件的打开方式了： context.openFileInput(file); Android中的文件读写具有权限控制，所以使用context(Activity的父类)来打开文件，文件在相同的Package中共享。这里的 Package的概念同Preferences中所述的Package，不同于Java中的Package。

数据写入

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public static void write(Context context, String file, String msg) {
try {
FileOutputStream stream = context.openFileOutput(file,
Context.MODE_WORLD_WRITEABLE);
stream.write(msg.getBytes());
stream.flush();
stream.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}
public static void write(Context context, String file, String msg) {
try {
FileOutputStream stream = context.openFileOutput(file,
Context.MODE_WORLD_WRITEABLE);
stream.write(msg.getBytes());
stream.flush();
stream.close();
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}

在这里打开文件的时候，声明了文件打开的方式。

一般来说，直接使用文件可能不太好用，尤其是，我们想要存放一些琐碎的数据，那么要生成一些琐碎的文件，或者在同一文件中定义一下格式。其实也可以将其包装成Properties来使用：

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public static Properties load(Context context, String file) {
Properties properties = new Properties();
try {
FileInputStream stream = context.openFileInput(file);
properties.load(stream);
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
return properties;
}

public static void store(Context context, String file, Properties properties) {
try {
FileOutputStream stream = context.openFileOutput(file,
Context.MODE_WORLD_WRITEABLE);
properties.store(stream, "");
} catch (FileNotFoundException e) {
} catch (IOException e) {
}
}

android 读取文件内容操作2

读：
public String ReadSettings(Context context){
FileInputStream fIn = null;
InputStreamReader isr = null;

char[] inputBuffer = new char[255];
String data = null;

try{
fIn = openFileInput("settings.dat");
isr = new InputStreamReader(fIn);
isr.read(inputBuffer);
data = new String(inputBuffer);
Toast.makeText(context, "Settings read",Toast.LENGTH_SHORT).show();
}
catch (Exception e) {
e.printStackTrace();
Toast.makeText(context, "Settings not read",Toast.LENGTH_SHORT).show();
}
finally {
try {
isr.close();
fIn.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return data;
}

写：
public void WriteSettings(Context context, String data){
FileOutputStream fOut = null;
OutputStreamWriter osw = null;

try{
fOut = openFileOutput("settings.dat",MODE_PRIVATE);
osw = new OutputStreamWriter(fOut);
osw.write(data);
osw.flush();
Toast.makeText(context, "Settings saved",Toast.LENGTH_SHORT).show();
}
catch (Exception e) {
e.printStackTrace();
Toast.makeText(context, "Settings not saved",Toast.LENGTH_SHORT).show();
}
finally {
try {
osw.close();
fOut.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

使用方法：
WriteSettings(this,"setting0, setting1, setting2");
String data[] = ReadSettings(this).split(",");

android 读取文件内容操作

android 读取文件内容操作2

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