java中outputStream與inputStream的相互轉換

/*做一個功能驗證，要用到inputStream與outputStream的轉換，本以為很簡單的東東
搞了蠻久，從"程序員 閆帆"處取得一段代碼*/
package com.boco.test;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

public class ConvertUtil {
    //inputStream轉outputStream
    public ByteArrayOutputStream parse(InputStream in) throws Exception
    {
        ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
        int ch;
        while ((ch = in.read()) != -1) {   
            swapStream.write(ch);   
        }
        return swapStream;
    }
    //outputStream轉inputStream
    public ByteArrayInputStream parse(OutputStream out) throws Exception
    {
        ByteArrayOutputStream   baos=new   ByteArrayOutputStream();
        baos=(ByteArrayOutputStream) out;
        ByteArrayInputStream swapStream = new ByteArrayInputStream(baos.toByteArray());
        return swapStream;
    }
    //inputStream轉String
    public String parse_String(InputStream in) throws Exception
    {
        ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
        int ch;
        while ((ch = in.read()) != -1) {   
            swapStream.write(ch);   
        }
        return swapStream.toString();
    }
    //OutputStream 轉String
    public String parse_String(OutputStream out)throws Exception
    {
        ByteArrayOutputStream   baos=new   ByteArrayOutputStream();
        baos=(ByteArrayOutputStream) out;
        ByteArrayInputStream swapStream = new ByteArrayInputStream(baos.toByteArray());
        return swapStream.toString();
    }
    //String轉inputStream
    public ByteArrayInputStream parse_inputStream(String in)throws Exception
    {
        ByteArrayInputStream input=new ByteArrayInputStream(in.getBytes());
        return input;
    }
    //String 轉outputStream
    public ByteArrayOutputStream parse_outputStream(String in)throws Exception
    {
        return parse(parse_inputStream(in));
    }
}