java常用流处理工具StreamTool 常见的InputStream流转字符串, 转字节数组等等

ava 常用流处理工具 StreamTool ，常见的InputStream 流转字符串, 转字节数组等等

**应用场景：

** 1. 文件上传

2. js / css / img 等文件读取输出。 转字符串输出 (js & css) , 转字节数组输出 (img .. swf etc...)

3. 抓取指定 URL 连接的资源。

例如读取 javaniu 首页的 HTML 源代码

4. 如你所见....

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * <pre>
 * Java 常用流处理工具
 * </pre>
 *
 * @project baidamei
 * @author cevencheng <cevencheng@gmail.com>
 * @create 2012-11-29 下午5:17:32
 */
public class StreamTool {

  /**
   * 将流另存为文件
   *
   * @param is
   * @param outfile
   */
  public void streamSaveAsFile(InputStream is, File outfile) {
    FileOutputStream fos = null;
    try {
      File file = outfile;
      fos = new FileOutputStream(file);
      byte[] buffer = new byte[1024];
      int len;
      while((len = is.read(buffer)) > 0){
        fos.write(buffer, 0, len);
      }

    } catch (Exception e) {
      e.printStackTrace();
      throw new RuntimeException(e);
    } finally {
      try {
        is.close();
        fos.close();
      } catch (Exception e2) {
        e2.printStackTrace();
        throw new RuntimeException(e2);
      }
    }
  }
  /**
   * Read an input stream into a string
   * @param in
   * @return
   * @throws IOException
   */
  static public String streamToString(InputStream in) throws IOException {
    StringBuffer out = new StringBuffer();
    byte[] b = new byte[4096];
    for (int n; (n = in.read(b)) != -1;) {
      out.append(new String(b, 0, n));
    }
    return out.toString();
  }
  public static byte[] stream2Byte(InputStream is) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    int len = 0;
    byte[] b = new byte[1024];
    while ((len = is.read(b, 0, b.length)) != -1) {
        baos.write(b, 0, len);
    }
    byte[] buffer =  baos.toByteArray();
    return buffer;
  }
  /**
     * @方法功能 InputStream 转为 byte
     * @param InputStream
     * @return 字节数组
     * @throws Exception
     */
    public static byte[] inputStream2Byte(InputStream inStream)
            throws Exception {
        // ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
        // byte[] buffer = new byte[1024];
        // int len = -1;
        // while ((len = inStream.read(buffer)) != -1) {
        // outSteam.write(buffer, 0, len);
        // }
        // outSteam.close();
        // inStream.close();
        // return outSteam.toByteArray();
        int count = 0;
        while (count == 0) {
            count = inStream.available();
        }
        byte[] b = new byte[count];
        inStream.read(b);
        return b;
    }  

    /**
     * @方法功能 byte 转为 InputStream
     * @param 字节数组
     * @return InputStream
     * @throws Exception
     */
    public static InputStream byte2InputStream(byte[] b) throws Exception {
        InputStream is = new ByteArrayInputStream(b);
        return is;
    }  

    /**
     * @功能 短整型与字节的转换
     * @param 短整型
     * @return 两位的字节数组
     */
    public static byte[] shortToByte(short number) {
        int temp = number;
        byte[] b = new byte[2];
        for (int i = 0; i < b.length; i++) {
            b[i] = new Integer(temp & 0xff).byteValue();// 将最低位保存在最低位
            temp = temp >> 8; // 向右移8位
        }
        return b;
    }  

    /**
     * @功能 字节的转换与短整型
     * @param 两位的字节数组
     * @return 短整型
     */
    public static short byteToShort(byte[] b) {
        short s = 0;
        short s0 = (short) (b[0] & 0xff);// 最低位
        short s1 = (short) (b[1] & 0xff);
        s1 <<= 8;
        s = (short) (s0 | s1);
        return s;
    }  

    /**
     * @方法功能 整型与字节数组的转换
     * @param 整型
     * @return 四位的字节数组
     */
    public static byte[] intToByte(int i) {
        byte[] bt = new byte[4];
        bt[0] = (byte) (0xff & i);
        bt[1] = (byte) ((0xff00 & i) >> 8);
        bt[2] = (byte) ((0xff0000 & i) >> 16);
        bt[3] = (byte) ((0xff000000 & i) >> 24);
        return bt;
    }  

    /**
     * @方法功能 字节数组和整型的转换
     * @param 字节数组
     * @return 整型
     * @author
     */
    public static int bytesToInt(byte[] bytes) {
        int num = bytes[0] & 0xFF;
        num |= ((bytes[1] << 8) & 0xFF00);
        num |= ((bytes[2] << 16) & 0xFF0000);
        num |= ((bytes[3] << 24) & 0xFF000000);
        return num;
    }  

    /**
     * @方法功能 字节数组和长整型的转换
     * @param 字节数组
     * @return 长整型
     */
    public static byte[] longToByte(long number) {
        long temp = number;
        byte[] b = new byte[8];
        for (int i = 0; i < b.length; i++) {
            b[i] = new Long(temp & 0xff).byteValue();
            // 将最低位保存在最低位
            temp = temp >> 8;
            // 向右移8位
        }
        return b;
    }  

    /**
     * @方法功能 字节数组和长整型的转换
     * @param 字节数组
     * @return 长整型
     */
    public static long byteToLong(byte[] b) {
        long s = 0;
        long s0 = b[0] & 0xff;// 最低位
        long s1 = b[1] & 0xff;
        long s2 = b[2] & 0xff;
        long s3 = b[3] & 0xff;
        long s4 = b[4] & 0xff;// 最低位
        long s5 = b[5] & 0xff;
        long s6 = b[6] & 0xff;
        long s7 = b[7] & 0xff; // s0不变
        s1 <<= 8;
        s2 <<= 16;
        s3 <<= 24;
        s4 <<= 8 * 4;
        s5 <<= 8 * 5;
        s6 <<= 8 * 6;
        s7 <<= 8 * 7;
        s = s0 | s1 | s2 | s3 | s4 | s5 | s6 | s7;
        return s;
    }
}