http断点续传简单实现（java)

/* !>T.*8  
**SiteFileFetch.java .8hB <G  
*/ m`!C|?hu  
package NetFox; bj4cW\b(  
import java.io.*; _y&m4Vuu  
import java.net.*; !4cR&@[  
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public class SiteFileFetch extends Thread { Z.+-MNWV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X96>N{C*>  
long[] nStartPos; //开始位置 kD:O$8[J8  
long[] nEndPos; //结束位置 6r/NdI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 aObWd5~  
long nFileLength; //文件长度 ]YQ[ )  
boolean bFirst = true; //是否第一次取文件 >=-w2&  
boolean bStop = false; //停止标志 vwDnz/-  
File tmpFile; //文件下载的临时信息 k`Nc<nN8  
DataOutputStream output; //输出到文件的输出流 l`8S1~j
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?ihkV?;)  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'L)
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{ %E Jv!u*-  
siteInfoBean = bean; | Zx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X=)Ue  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "M5P-l$p}  
if(tmpFile.exists ()) MkZm =Sf  
{ M7{w7}B0@  
bFirst = false; 8X`iMFa.P  
read_nPos(); :U!knb"/>  
} ez_qG=J .  
else UR6.zE4=_  
{ e`ti*1]q  
nStartPos = new long[bean.getNSplitter()]; 4]O{Nko)  
nEndPos = new long[bean.getNSplitter()]; W(ITs}O  
} P.
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} }I<r=?  
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public void run() H%NIdgo}  
{ nPh5(&E  
//获得文件长度 w1B!z  
//分割文件 [YG\a5QK  
//实例FileSplitterFetch ?WE#%W7U  
//启动FileSplitterFetch线程
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//等待子线程返回 <4SY'-w  
try{ IMLk{y%6  
if(bFirst) T!e]=  
{ )$K )`uqb  
nFileLength = getFileSize(); XB,  2+  
if(nFileLength == -1) 8 hx4N  
{ ]TQ2PVN2  
System.err.println("File Length is not known!"); R=P=?U.  
} Y`jvza%  
else if(nFileLength == -2) :xISS  
{ (#GOXz  
System.err.println("File is not access!"); 7K3S\oPej  
} -b+VzVJZ  
else qeLfO  
{ >aXyi3B  
for(int i=0;i<nStartPos.length;i++) p\OUxAm  
{ h<2o5c|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x`K<z J  
} ?t++IEoP  
for(int i=0;i<nEndPos.length-1;i++) 8o43J;mA  
{ AE!DftI  
nEndPos = nStartPos[i+1]; h^R EBPe  
} zu}oeAQc$  
nEndPos[nEndPos.length-1] = nFileLength; s<VNW  
} @NlE2s6a  
} +-YMW;5  
7/QQ&7+NkS  
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//启动子线程  gSQq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6Mu_
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for(int i=0;i<nStartPos.length;i++) *YmR7g|k  
{ sFv68Ag+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qYFOHu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0dxEV]  
nStartPos,nEndPos,i); dPplZ,Y%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &}:'YK*X  
fileSplitterFetch.start(); \'Oi0qo>  
} ZHT_o\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m  "'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /H.w0fu&.S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 94 58.!3  
nEndPos = " + nFileLength); %+gYZv-  
// fileSplitterFetch[nPos.length-1].start(); =Hplg>h)  
i]&C=X  
!J`>;&  
//等待子线程结束 )
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//int count = 0; 3)\jUVuj  
//是否结束while循环 U;QTA8|!&  
boolean breakWhile = false; 9IJBK  
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while(!bStop) 6'CZfs\  
{ 2F9Gx;}t5=  
write_nPos(); xR;>n[6  
Utility.sleep(500); D^
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breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) }jHS  
{ ~I[Z2&I  
if(!fileSplitterFetch.bDownOver) "TW%-67  
{ KMC]<  
breakWhile = false; rTTde^^_  
break; 6;s.%W  
} D2N| A  
} K8[vJ7(!|  
if(breakWhile) Y,BzBUWK  
break; Y'-@O"pK  
l;{
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//count++; :/YHU3~Y  
//if(count>4) *_feD+rq  
// siteStop(); o/0cd  
} 38ac~1HjE  
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System.err.println("文件下载结束！"); |2RoDW  
} [+,%T;d;  
catch(Exception e){e.printStackTrace ();} : :;YS9e  
} y04md A6<  
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6/{V#.(  
//获得文件长度
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public long getFileSize() ."`mh&+`  
{ >]b>gc?3  
int nFileLength = -1; &CP0T:h  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); X}jWNN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]QM{aSvXA  
httpConnection.setRequestProperty("User-Agent","NetFox"); i'XW)n  
N RB>X  
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int responseCode=httpConnection.getResponseCode(); T}fH  
if(responseCode>=400) Nf@-i`  
{ ;MSdTHN"  
processErrorCode(responseCode); 72Zp%a=  
return -2; //-2 represent access is error VtM:~|v  
} )|52B;yZx  
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String sHeader; NT(gXEZ  
S
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for(int i=1;;i++) 5&Y%N(  
{ D,$!.5OA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D1xIRyc/  
//Utility.log(in.readLine()); k@}?!V*l  
sHeader=httpConnection.getHeaderFieldKey(i); dP[vXhc  
if(sHeader!=null) 0EWov~Y?  
{ AQ}(v,DOb  
if(sHeader.equals("Content-Length")) lI,lR  
{ Q4~/Tl;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !u)>XS^E
  
break; KImBQ2^Tu  
} gteG*pi  
} 8]G  
else U2hPsF4f  
break; !V%h0OE\  
} whH_<@!  
} cx+w_D9b!  
catch(IOException e){e.printStackTrace ();} tccw0  
catch(Exception e){e.printStackTrace ();} QmHj=s:x\  
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Utility.log(nFileLength); .$o0$`}  
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return nFileLength; 3EY>XS  
} 30BFwNE  
s)dL^lj;  
 !' }  
//保存下载信息（文件指针位置） b\Wlpb=QZ  
private void write_nPos() j<*  
{ c@|!0 U%j  
try{ k4HE'WY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S*aMUV&  
output.writeInt(nStartPos.length); ,Wbr; zb  
for(int i=0;i<nStartPos.length;i++) 9`a1xnL  
{ UrC>n  
// output.writeLong(nPos); N}|<P[LW  
output.writeLong(fileSplitterFetch.nStartPos); g$^:2MT"aQ  
output.writeLong(fileSplitterFetch.nEndPos); NA :_yA"  
} /m"#uC!\  
output.close(); ~]w|ULNa3|  
} _ ^2\/@  
catch(IOException e){e.printStackTrace ();} bUcEQGHcZ=  
catch(Exception e){e.printStackTrace ();} 9~rrN60Q  
} ;nSOeAF)Q  
. X:
 
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//读取保存的下载信息（文件指针位置） %pJRu-D  
private void read_nPos() q.}M^iDe  
{ +VSq[P  
try{ o[A y2"e?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {M_*hR;lL  
int nCount = input.readInt(); s^&Oh*SP*  
nStartPos = new long[nCount]; =/#+,  
nEndPos = new long[nCount]; _N @h  
for(int i=0;i<nStartPos.length;i++) c4Leh"
ry  
{ :cE6-Fv  
nStartPos = input.readLong(); <<SUIY@X  
nEndPos = input.readLong();  /#FU"  
} ,P>xpfdK  
input.close(); xj!G9x<!  
} dvc=<!"'S  
catch(IOException e){e.printStackTrace ();} #9/^)^k  
catch(Exception e){e.printStackTrace ();} Nn/f*GDvK  
} #F^0uUjq  
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private void processErrorCode(int nErrorCode) f{HjM? Mb3  
{ >N bb0T  
System.err.println("Error Code : " + nErrorCode); o5(~nQ  
} i"_@iN0N  
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K*/X{3J;  
//停止文件下载 c/'Cju W  
public void siteStop() Iq?#kV9)  
{ <Pnz$nH:e  
bStop = true; Sb|9U8h  
for(int i=0;i<nStartPos.length;i++) <E&8g[x6  
fileSplitterFetch.splitterStop(); $sxm MP  
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} x & ZW f?  
} v<AFcY  
//负责部分文件的抓取 AE@N:a  
**FileSplitterFetch.java ll^#I/  
*/ r7zS4;b  
package NetFox; n5U-D0/Q  
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import java.io.*; RG8Ek"D@  
import java.net.*; \'Z^rjB  
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public class FileSplitterFetch extends Thread { bm\Zp  
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String sURL; //File URL 8q/3}AnI  
long nStartPos; //File Snippet Start Position S)\Yc=~h  
long nEndPos; //File Snippet End Position (/[wM>q:r  
int nThreadID; //Thread's ID AdL>?SG%  
boolean bDownOver = false; //Downing is over 4Q?3gA1  
boolean bStop = false; //Stop identical ls,;ozU  
FileAccessI fileAccessI = null; //File Access interface V"u .u  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [B1h0IR  
{ '2:HBJ  
this.sURL = sURL; (WuJ9  
this.nStartPos = nStart; >"|"Gy (  
this.nEndPos = nEnd; ^fqco9^;  
nThreadID = id; y{#9&ct&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 17ol %3 M  
} HxnWM\p  
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public void run() rk)h_zN  
{ 8r\;8all  
while(nStartPos < nEndPos && !bStop) Y7GHIzX  
{ @\?QZX(H  
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try{ grZ?F~P8  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !)//b]  
httpConnection.setRequestProperty("User-Agent","NetFox"); g&?RQ  
String sProperty = "bytes="+nStartPos+"-"; !WgVk7aP`  
httpConnection.setRequestProperty("RANGE",sProperty); C#oH7o+_.  
Utility.log(sProperty); [eLU}4v{  
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InputStream input = httpConnection.getInputStream(); P^-daRb  
//logResponseHead(httpConnection); Z~Vups#+f  
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byte[] b = new byte[1024]; e .(  
int nRead; iji2gWV}h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H6V!W\:s  
{ +A
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nStartPos += fileAccessI.write(b,0,nRead); PCX X[N  
//if(nThreadID == 1) h7 c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .[:2M9Rx  
} @q++eGm\Q  
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Utility.log("Thread " + nThreadID + " is over!"); c0.? d]  
bDownOver = true; !McRtxq?~  
//nPos = fileAccessI.write (b,0,nRead); `Qxdb1>mjY  
} .?dYY;P  
catch(Exception e){e.printStackTrace ();} vcz?;lg  
} 0UN65JBuD  
} %(d0`9  
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//打印回应的头信息 me
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public void logResponseHead(HttpURLConnection con) Y<)9TU:D!  
{ rZkl0Y;n\  
for(int i=1;;i++) 5hg ^K^ZZ  
{ ,cwjieM  
String header=con.getHeaderFieldKey(i); +WfO2V.
 
if(header!=null) 1 R,?kUa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %O02xr=  
Utility.log(header+" : "+con.getHeaderField(header)); 8iXt8XY3  
else $e/[!3CASP  
break; kx6-8j3gD7  
} t<H@c9{;*  
} DEN (pA\  
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public void splitterStop() ^#p+#_*V  
{ K<~J*k<v  
bStop = true; ^/:G`'  
} 4Tn97G7  
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} ;Vlt4,s)  
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/* 7Ug^aA  
**FileAccess.java dW} m44X  
*//文件访问(定位，写) y8/+kn +  
package NetFox; g>;u} +lO  
import java.io.*; Nny#}k Bt  
=DLVWz/<  
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public class FileAccessI implements Serializable{ {/Qg4pc!  
Rpou.RrXR7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8%#pv
}  
RandomAccessFile oSavedFile; ]>H'CM4JR  
long nPos; w[hT,$n  
OTV$8{  
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public FileAccessI() throws IOException QNxY`  
{  Mcm%G#  
this("",0); L)-1( e<x  
} TV[@
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public FileAccessI(String sName,long nPos) throws IOException :7 OhplI  
{ DWmViuZmL  
oSavedFile = new RandomAccessFile(sName,"rw"); "C'T>^qw*  
this.nPos = nPos; u3])_oj=  
oSavedFile.seek(nPos); ~=i<O&nai  
} jPA^SxM  
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public synchronized int write(byte[] b,int nStart,int nLen) aZB$%#'vR  
{ o@W:PmKW  
int n = -1; T.GB*  
try{ AH'4k(-  
oSavedFile.write(b,nStart,nLen); j@C*kj;-  
n = nLen; b5t:">wC  
} )L/o|%r!  
catch(IOException e) o~tL;(sz  
{ xG~7kj3  
e.printStackTrace (); &p_V<\(%  
} Ew>lk9La(  
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=+"=|cQ  
return n; K3-Cuku  
} 8XhGo2zf  
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} L{uQ:;w1  
/ &#b*46  
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/* {~{</ g/  
**SiteInfoBean.java
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*/ P?$Iht.^
 
package NetFox; EU4j'1!&g<  
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public class SiteInfoBean { d8%sGH  
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private String sSiteURL; //Site's URL M TOZ:b  
private String sFilePath; //Saved File's Path x A"V!8C  
private String sFileName; //Saved File's Name )Oix$B!-  
private int nSplitter; //Count of Splited Downloading File D9;s%  
 LAO2Py#  
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public SiteInfoBean() bC0DzBnM;  
{//nSplitter的缺省值为5 q:-1ul  
//default value of nSplitter is 5 _&}z+(Ug  
this("","","",5); <nbc RO.  
} Dx>~^ ^<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /Q\|u:oO,  
{ #5=!ew  
sSiteURL= sURL; WN3]xw3  
sFilePath = sPath; DxJY{e9  
sFileName = sName; 0p[-M`D  
this.nSplitter = nSpiltter; 'q, L*  
!B:wzb_  
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} Rn5{s3?F~2  
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public String getSSiteURL() #S') i1;  
{ 66Bx,]"6  
return sSiteURL; h7cE"m  
} 2R>!Wj'G+o  
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public void setSSiteURL(String value) 8Y&_X0T|  
{ "d c- !  
sSiteURL = value; pu,|_N[xq8  
} uL9O_a;!  
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public String getSFilePath() ]D&\|,,(
 
{ Fd1jElt  
return sFilePath; L]#b=Y  
} <z R CT  
 #[yZP9  
4StoEgFS  
public void setSFilePath(String value) ;$/]6@bqB  
{ mWX{I2  
sFilePath = value; 8 GW0w
 
} #55_hY#  
hL}AgY@  
NZ:KJ8ea"  
public String getSFileName() iNv"!'|  
{ *TC#|5  
return sFileName; h$$2(!G4  
} H rI(uZ]  
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public void setSFileName(String value) '-M9v3itC  
{ &"mWi-Mpl  
sFileName = value; Pm==m9  
} 9Z lfY1=  
$3yn-'o'A  
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public int getNSplitter() 0q_?<v_1  
{ d0}P  
return nSplitter; :[!b";pR  
} ]Ia}H+&  
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@ *n oma  
public void setNSplitter(int nCount) ,^@z;xF  
{ cxc-|Xori  
nSplitter = nCount; @ w?,7i-S  
} !T$h?o  
} @:K={AIa  
l?:S)[:  
s>ohXISB[  
/* 
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**Utility.java 2g$;ZBHO|8  
*/ xy+hrbD)j  
package NetFox; =.2)wA"e'  
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QW= X#yrDO  
public class Utility { (
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-(  
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public Utility() cd]def[d  
{ A&L2&ofV&q  
Wh^wKF~%  
X{tfF!+iy  
} rL|9Xru  
- sL4tMP  
//线程睡眠 !;E{D  
public static void sleep(int nSecond) &Rt^G  
{ 'W*ODAz6  
try{ ~As_O6JI  
Thread.sleep(nSecond); ?v}S9z  
} w<Ot0&&  
catch(Exception e) KZ$^Q<d^  
{ ?$~5ti#\  
e.printStackTrace (); Q&8epO|J  
} k`NXYf:  
} :[?65q{  
|C}= 1  
//日志 jq(QL%)_O  
public static void log(String sMsg) wPl9%  
{ Tno 0Q +  
System.err.println(sMsg); Lv7$@|"H9  
} {)PgN  
"HtaJVp//  
.wf$]oQQ  
public static void log(int sMsg) =&#t("  
{ 5q _n6
9b  
System.err.println(sMsg); rFhi:uRV  
} Cp^`-=r+  
} #r'S@:[  
2k+u_tj>  
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/* 1-~sj)*k  
**TestMethod.java [ ]42$5eof  
*/ UAOH9*9*  
package NetFox; h7J4 p  
8XD_p);Oy  
|6 E !wW  
public class TestMethod { N7-LgP  
cS RmC  
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public TestMethod() ^ wb9n  
{ ///xx/weblogic60b2_win.exe BQL](Y"  
try{ GU7f27p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ca,U>'(y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S3gd'Bahq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a\tv,Lx  
fileFetch.start(); WP >VQZ&  
} t(Gg 1  
catch(Exception e){e.printStackTrace ();} vQmqYyOc2  
$Go)Zs-bL?  
Ti$_V_  
} XvIY=~  
Zb$P`~(%  
`!y/$7p  
public static void main(String[] args) 4q*mEV  
{ 5U6b\jxX  
new TestMethod(); Zqj EVVB  
}  >f*Zf(F  
} .svlJSx  
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