byte[]、bitmap、inputstream、String之间的转换

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;

public class Demo {
/**
* bitmap 转 byte[]数组
*/
public byte[] bitmap2byteArray(Bitmap bitmap){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] bytes = baos.toByteArray();
return bytes;
}

/** 
 * bitmap 转  inputstream 
 */  
public InputStream bitmap2InputStream(Bitmap bitmap){  
    ByteArrayOutputStream baos = new ByteArrayOutputStream();  
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);  
    InputStream is = new ByteArrayInputStream(baos.toByteArray());  
    return is;  
}  
  
/** 
 * byte[]数组   转   bitmap 
 */  
public Bitmap byteArray2Bitmap(byte[] bytes){  
    Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);  
    return bitmap;  
}  
  
/** 
 * inputstream  转   bitmap  
 */  
public Bitmap inputStream2Bitmap(InputStream is){  
    Bitmap bitmap = BitmapFactory.decodeStream(is);  
    return bitmap;  
}  

/** 
 * Drawable 转  bitmap 
 */  
public Bitmap drawable2Bitmap(Drawable img){  
    BitmapDrawable bd = (BitmapDrawable) img;  
    Bitmap bitmap = bd.getBitmap();  
    return bitmap;  
}  
  
/** 
 * bitmap 转  Drawable 
 */  
public Drawable bitmap2Drawable(Bitmap bitmap){  
    BitmapDrawable bd = new BitmapDrawable(bitmap);  
    Drawable img = bd;  
    return img;  
}  
  
/** 
 * String 转  byte[]数组 
 */  
public byte[] string2ByteArray(String str,String charset){  
    byte[] bytes = null;  
    if(charset == null){  
        bytes = str.getBytes();  
    }else{  
        try {  
            //如charset = "utf-8"  
            bytes = str.getBytes(charset);  
        } catch (Exception e) {  
            // TODO: handle exception  
        }  
          
    }  
    return bytes;  
}  
  
/** 
 * String 转  inputstream 
 */  
public InputStream string2InputStream(String str){  
    InputStream is = new ByteArrayInputStream(str.getBytes());  
    return is;  
}  
  
/** 
 * inputstream 转  String  方法01 
 */  
public String inputStream2String01(InputStream is) throws IOException{  
    ByteArrayOutputStream baos = new ByteArrayOutputStream();  
    int i = -1;  
    while((i=is.read()) != -1){  
        baos.write(i);  
    }  
    return baos.toString();  
}  
  
/** 
 * inputstream 转  String   方法02 
 */  
public String inputStream2String02(InputStream is) throws IOException{  
    BufferedReader br = new BufferedReader(new InputStreamReader(is));  
    StringBuilder sb = new StringBuilder();  
    String line = null;  
    while((line=br.readLine()) != null){  
        sb.append(line+"\n");  
    }  
      
    return sb.toString();  
}  
  
/** 
 * inputstream 转  String   方法03 
 */  
public String inputSteam2String03(InputStream is) throws IOException{  
    StringBuilder sb = new StringBuilder();  
    byte[] b =new byte[1024];  
    for(int n; (n=is.read(b)) != -1;){  
        String s = new String(b, 0, n);  
        sb.append(s);  
    }  
    return sb.toString();  
}  
  }