http断点续传简单实现（java)

/* %Y%r2  
**SiteFileFetch.java g%l ,a3"  
*/ |J,zU6t  
package NetFox; ?/OF=C#  
import java.io.*; /^AH/,p  
import java.net.*; O\.^H/  
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public class SiteFileFetch extends Thread { Q3tyK{JE  
n!4\w>h  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~jL%l  
long[] nStartPos; //开始位置 a$|U4Eqo  
long[] nEndPos; //结束位置 #zTy7ZS,0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w2.] 3QAZ  
long nFileLength; //文件长度 ?OFa Q  
boolean bFirst = true; //是否第一次取文件 gZ4' w`4r  
boolean bStop = false; //停止标志 u-t=M]  
File tmpFile; //文件下载的临时信息 (M$0'B
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DataOutputStream output; //输出到文件的输出流 HpEd$+Mz  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AOZ C D{  
public SiteFileFetch(SiteInfoBean bean) throws IOException M5h r0R{  
{ MvpJ0Y (  
siteInfoBean = bean; Zu,:}+niU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U`qkeNd  
if(tmpFile.exists ()) vHf)gi}O|  
{ p75o1RU  
bFirst = false; d <}'eBT'  
read_nPos(); rJ Jx8)M  
} k`m7j[A]l  
else H ni^S  
{ L*Z.T^h  
nStartPos = new long[bean.getNSplitter()]; 8X7??f1;Y  
nEndPos = new long[bean.getNSplitter()]; _/LGGt4&%  
} .2fvRN92  
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} G x[ZHpy;  
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public void run() tVRN3fJH  
{ 1Z}5ykM3  
//获得文件长度 *DPX4P  
//分割文件 [
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//实例FileSplitterFetch /A7( `l;6  
//启动FileSplitterFetch线程 O=2|'L'h!  
//等待子线程返回 LDjtkD.r  
try{ Mh7m2\fLbd  
if(bFirst) wD9K\%jIr!  
{ ln82pQD2Y~  
nFileLength = getFileSize(); XZIapT  
if(nFileLength == -1) `NW/Z/_  
{ cj[b^Wv:  
System.err.println("File Length is not known!"); %)lp]Y33  
} jA{5)-g  
else if(nFileLength == -2) }Ja-0v)Wf  
{ <K[y~9u  
System.err.println("File is not access!"); tY"eoPme  
} [KK |_  
else uE's&H  
{ +Y7M7  
for(int i=0;i<nStartPos.length;i++) 8TP$?8l  
{ =p@`bx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hObL=^F  
} {zb'Z Yz  
for(int i=0;i<nEndPos.length-1;i++) p1KhI;^  
{ -8n1y[  
nEndPos = nStartPos[i+1]; [9"
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} = 7y-o  
nEndPos[nEndPos.length-1] = nFileLength; ,sL'T[tuiU  
} _N`.1Dl%Q  
} *igmi9A  
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//启动子线程 60+zoL'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A%8 Q}s$<s  
for(int i=0;i<nStartPos.length;i++) D^[l~K  
{ & &}_[{fc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ['mpxtG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V+`kB3GV  
nStartPos,nEndPos,i); _EMI%P&s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); layxtECP(  
fileSplitterFetch.start(); c]9gf\WW  
} KR?;7*qF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *wTX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rRe5Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xTAfVN  
nEndPos = " + nFileLength); =z# tr
Q{  
// fileSplitterFetch[nPos.length-1].start(); X/4CXtX^  
JG!B3^qB  

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//等待子线程结束 [K4cxqlfk  
//int count = 0; AIHH@z   
//是否结束while循环 IO\1nB$0nb  
boolean breakWhile = false; ~}_^$l8#-Q  
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while(!bStop) e)e(f"t6Q  
{ nd'D0<%  
write_nPos(); )U\i7[k>  
Utility.sleep(500); HkD.W6A3  
breakWhile = true; )g:5}+  
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for(int i=0;i<nStartPos.length;i++) L~&S<5?  
{ v^&HZk=(  
if(!fileSplitterFetch.bDownOver) XC3)#D#HGh  
{ c^W;p2^  
breakWhile = false; (pELd(*Ga  
break; &;$uU  
} ?T/4 =  
} WDw<kX6p  
if(breakWhile) Gpu[<Z4  
break; )?
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|<{SSA  
//count++; XIIq0I  
//if(count>4) *8)?ZZMM  
// siteStop(); }%XB*pzQ  
} "r6qFxY  
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System.err.println("文件下载结束！"); a#1r'z~]}  
} 9':Ipf&x  
catch(Exception e){e.printStackTrace ();} EeYL~ORdi  
} dg|+?M^9`  
'pA%lc)  
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//获得文件长度 >9w^C1"  
public long getFileSize() JlSqTfA  
{
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int nFileLength = -1; $@VJ@JAe  
try{ <);j5)/  
URL url = new URL(siteInfoBean.getSSiteURL()); `)O9 '568  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XB'rh F8rl  
httpConnection.setRequestProperty("User-Agent","NetFox"); )nHMXZ>Td  
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int responseCode=httpConnection.getResponseCode(); S[y'{;  
if(responseCode>=400) u4lM>(3Y}  
{ (U5XB [r_P  
processErrorCode(responseCode); VsA
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return -2; //-2 represent access is error {ZUk!o>m@  
} U$D:
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String sHeader;  '0f!o&?g  
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for(int i=1;;i++)  e$  
{ FBNi (D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4=q4_ \_T  
//Utility.log(in.readLine()); oi Q3E  
sHeader=httpConnection.getHeaderFieldKey(i); uEPm[oyX  
if(sHeader!=null) Il/`#b@h  
{ !o'a]8  
if(sHeader.equals("Content-Length")) ]@SEOc@ j  
{ LZ#A`
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~DLxIe  
break; lxTqGwx  
} d>M0:  
} <mLU-'c@  
else "QfF]/:  
break; d;%~\+)x4  
} @ &c@  
} [9EL[}  
catch(IOException e){e.printStackTrace ();} #)D$\0ag  
catch(Exception e){e.printStackTrace ();} @
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Utility.log(nFileLength); aS3-A4  
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return nFileLength; "'8o8g  
} UJX5}36  
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[aC2ktI  
//保存下载信息（文件指针位置） !ImtnU}  
private void write_nPos() ~i@Z4tj7  
{ $/i;UUd  
try{ D/zp_9B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N'5!4JUI  
output.writeInt(nStartPos.length); BYDOTy/%nJ  
for(int i=0;i<nStartPos.length;i++) ! F&{I  
{ ?6^KY+ 5`C  
// output.writeLong(nPos); DOo34l6#  
output.writeLong(fileSplitterFetch.nStartPos); pzBd(d^*  
output.writeLong(fileSplitterFetch.nEndPos); 8>^O]5Wo`X  
} 0Z[8d0  
output.close(); 8J7<7Sx  
} ZYW=#df R  
catch(IOException e){e.printStackTrace ();} Jo ]8?U(^  
catch(Exception e){e.printStackTrace ();}  F_%&,"$  
} :] +D+[c)  
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Hb *&&  
//读取保存的下载信息（文件指针位置） [318Q%W&  
private void read_nPos() bxg9T(Bj
 
{ RIl+QA  
try{ q:v&wb%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Co>=<\yi  
int nCount = input.readInt(); m]U`7!  
nStartPos = new long[nCount]; $'VFb=?XrK  
nEndPos = new long[nCount]; HTCn=MZm ?  
for(int i=0;i<nStartPos.length;i++) tm}0kWx  
{ "Tm`V9  
nStartPos = input.readLong(); fL&bN[XA"$  
nEndPos = input.readLong(); y|%rW  
} viY&D  
input.close(); :AB$d~${M>  
} DPZG_{3D  
catch(IOException e){e.printStackTrace ();} m;nT ?kv  
catch(Exception e){e.printStackTrace ();} 1e#}+i!a  
} 3"hPplE  
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private void processErrorCode(int nErrorCode) #Hr>KQ5mJQ  
{ h~ =UFE%'  
System.err.println("Error Code : " + nErrorCode); _YW1Mk1  
} x;Jy-hMNl  
1yN/+Rq  
rBZ0(XSZQ  
//停止文件下载 (TV ye4Z  
public void siteStop() n_51-^*z  
{ }Z_w8+BZ  
bStop = true; F\Gi;6a  
for(int i=0;i<nStartPos.length;i++) tPHDnh^n]  
fileSplitterFetch.splitterStop(); tQ:)j^\  
>8nRP%r[5,  
/gKX%`ZF/r  
} G~I@'[ur  
} x\Bl^1&  
//负责部分文件的抓取 !e>EDYbY  
**FileSplitterFetch.java [g:ZIl4p\P  
*/ .n
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package NetFox; %_!YonRY|X  
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import java.io.*; spV/+jy{  
import java.net.*; dw8Ce8W  
eEIa=MB*  
|*Dklo9{  
public class FileSplitterFetch extends Thread { DKu4e  
R;gN^Yjk:  
}^;Tt-*k  
String sURL; //File URL 9GuG"^08  
long nStartPos; //File Snippet Start Position Q&;dXE h  
long nEndPos; //File Snippet End Position `Li3=!V[  
int nThreadID; //Thread's ID :;S]jNy}j)  
boolean bDownOver = false; //Downing is over O<Rm9tZ8  
boolean bStop = false; //Stop identical T<"Hh.h  
FileAccessI fileAccessI = null; //File Access interface gf^"sfNk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o })k@-oL  
{ p`)(  
this.sURL = sURL; PK@hf[YHe  
this.nStartPos = nStart; %l!Gt"\xm  
this.nEndPos = nEnd; G%w hOIFRq  
nThreadID = id; 8S[`(] )  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mr]IxTv  
} f\Fub
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00 Qn1  
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public void run() E`3yf9"  
{ 8r7~ >p~  
while(nStartPos < nEndPos && !bStop) j'#M'W3@  
{ Z> jk\[  
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try{ >L F y:a  
URL url = new URL(sURL); {k=H5<FV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AOhfQ:E 4  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;ZMm6o  
String sProperty = "bytes="+nStartPos+"-"; V)CS,w  
httpConnection.setRequestProperty("RANGE",sProperty); 8{aS$V"  
Utility.log(sProperty); y -j3d)T  
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InputStream input = httpConnection.getInputStream(); j^ VAA\  
//logResponseHead(httpConnection); x}t,v
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byte[] b = new byte[1024]; ;*K@8GnU  
int nRead; WZ@/
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QZ!;` ?(  
{ dGf:0xE"  
nStartPos += fileAccessI.write(b,0,nRead); Ergh]"AD6-  
//if(nThreadID == 1) EY=`/~|c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B2\R#&X.  
} +.gM"JV  
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Utility.log("Thread " + nThreadID + " is over!"); Enu/Nj 2  
bDownOver = true; -F.A1{l[.  
//nPos = fileAccessI.write (b,0,nRead); kk_$j_0  
} 0J-]  
catch(Exception e){e.printStackTrace ();} tW4|\-E"s4  
} n\8
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} nA:\G":\y  
o RT<h  
nX,2jT;@L  
//打印回应的头信息 +X
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public void logResponseHead(HttpURLConnection con) aChyl;#E  
{ oxkA+}^j8M  
for(int i=1;;i++) bqjj6bf'o  
{ /5 rWcX  
String header=con.getHeaderFieldKey(i); DA'A-C2  
if(header!=null) v0EF?$Wo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rv>K0= t0  
Utility.log(header+" : "+con.getHeaderField(header)); $FV!HD  
else @]$qJFXx  
break; |3\$\qa  
} _jkH}o '  
} N\ nr  
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public void splitterStop() gY'w=(/`  
{ OnGtIY  
bStop = true; r,^}/<*  
} HF@K$RPK  
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} @Y2"=QVt  

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^<L;"jl%  
/* ZP?k|sEH  
**FileAccess.java :LVM'c62c>  
*//文件访问(定位，写) ?w# >Cs(  
package NetFox; ^iubqtT]  
import java.io.*; K_`*ZV{r  
6u7(}K  
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public class FileAccessI implements Serializable{ .Z&OKWL  
1:7>Em<s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `#fOY$#XB  
RandomAccessFile oSavedFile; RYE::[O7  
long nPos; YO!,m<b^u  
=[{Pw8['  
g8XGZW!  
public FileAccessI() throws IOException z9HQFRbo[  
{ -f9M*7O<gf  
this("",0); /N%f78 Z  
} j)-D.bY0  
yN3Tk}{V  
<
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public FileAccessI(String sName,long nPos) throws IOException a #@Q.wL  
{ Qb|w\xT^Y  
oSavedFile = new RandomAccessFile(sName,"rw"); |B`-chK  
this.nPos = nPos; sxThz7#i)  
oSavedFile.seek(nPos); X8Sk  
} 7Wb.(` a<  

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public synchronized int write(byte[] b,int nStart,int nLen) 3]N}k|lb%  
{ (la<X<w  
int n = -1; @0 -B&w  
try{ kl
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oSavedFile.write(b,nStart,nLen); K,IOD t  
n = nLen; ~5!ukGK_  
} {t=Nnc15K  
catch(IOException e) A^K,[8VX  
{ +W;B8^imG  
e.printStackTrace (); _23sIUN c3  
} ,O[vxN1X*  
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return n; ^mJvB[ u|  
} q#p)E=$  
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} E`?BaCrG~  
hf?^#=k^  
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/* 5t<]|-i!  
**SiteInfoBean.java 3?O|X+$p
 
*/ ,gOQIS56  
package NetFox; W^Rb~b^?  
I2W2B3D` c  
aJ}sYf^  
public class SiteInfoBean { 'D/AL\1{p(  
)_Oc=/c|f  
#!5Nbe  
private String sSiteURL; //Site's URL u}:O[DG  
private String sFilePath; //Saved File's Path ^=W&p%Y(!  
private String sFileName; //Saved File's Name _bd#C  
private int nSplitter; //Count of Splited Downloading File PaDT)RrEM  
sN g"JQ  
vJCL m/}*  
public SiteInfoBean() uc<@ Fh(  
{//nSplitter的缺省值为5 gU~)(|Nu.  
//default value of nSplitter is 5 @\h(s#sn  
this("","","",5); qnS7z%H8  
} 62_$O"  
v8@dvT<  
7
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <R(2 9QN  
{ +|H'Ij$  
sSiteURL= sURL; \k,bz0  
sFilePath = sPath; i3"sArP"|  
sFileName = sName; AFFLnLA<L  
this.nSplitter = nSpiltter; \l2 s^7G_  
{DK:"ep  
3?XLHMxW  
} :L[6a>"neE  
{ &'TA  
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public String getSSiteURL() ks5'Z8X  
{ !kcg#+s91  
return sSiteURL; G8s`<:9*  
} YXtGuO\q  
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#~+#72+x7  
public void setSSiteURL(String value) ?>y-5B[K/(  
{
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sSiteURL = value; m?j!0>  
} `Z/IW  
vVW=1(QWI#  
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public String getSFilePath() 8joQPHkI\  
{ a 98  
return sFilePath; %RN-J*s]  
} X*"Kg  
kpH;D=;  
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public void setSFilePath(String value) JY2 F-0t)  
{ E(tBN]W.  
sFilePath = value; )DmiN^:  
} >, E$bm2  
Oez}C,0  
tTGK25&  
public String getSFileName() N%f!B"NQ  
{ yj~"C$s  
return sFileName; `t1$Ew
<  
} |y%].y)  
rcZ SC3  
QYgN39gp  
public void setSFileName(String value) :BX{*P  
{ 0Qp'}_  
sFileName = value; CFm1c1%Hg  
} oKi1=d+T  
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q|X4[E|{Q  
public int getNSplitter() @$P!
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{ ;p 5v3<PC  
return nSplitter; !>< %\K  
} 8 
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ox_h9=$-  
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public void setNSplitter(int nCount) ^<\} Y  
{ q#&#*6 )B  
nSplitter = nCount; cXcx_-  
} qW~R-g]  
} SMO%sZ]  
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RzRvu]]8  
/* @CU|3Qg  
**Utility.java G>,nZ/,A{  
*/ (}X?v`Y^W  
package NetFox; ;Uqx&5P}  
; eF4J  
Ccr+SR2  
public class Utility { e( o/we{  
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public Utility() };m7FO  
{ '?G[T28  
LAY)">*49H  
#* gU[9U~  
} X;6r$   
>?9 WeXG  
//线程睡眠 C6'*/wq  
public static void sleep(int nSecond) vvsNWA
 
{ HS`bto0*  
try{ k<'vP{  
Thread.sleep(nSecond); cCh5Jl@Z  
} JXY!c\,  
catch(Exception e) 22/?JWL>  
{ wEfz2Eq  
e.printStackTrace (); ]tQDk4&i  
} L.0} UXd  
} y/}VtD  
v!#`W  
//日志 e}R2J`7  
public static void log(String sMsg) 6PJJ?}P^1  
{ RC8)f8n  
System.err.println(sMsg); A:.IBctsd  
} /SCZ&  
D){"fw+b  
.hQ3A"  
public static void log(int sMsg) HhWwc#B  
{ cPx~|,)l  
System.err.println(sMsg); 7/&C;"  
} Y*kh$E%<#  
} Ql q#Zdru  
 ?+ -/';  
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/* P^b:?%  
**TestMethod.java 0r0\b*r  
*/ 8g[(nxI~  
package NetFox; #Z|%0r_~  
. QQ?w  
ez^*M:K  
public class TestMethod { k+WO &g*|  
.Yu<%  
;/?Z<[B  
public TestMethod() agU%z:M{  
{ ///xx/weblogic60b2_win.exe _'!N q  
try{  ko=aa5c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yD3bl%uZ
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GhG%>U#&a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K2x
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fileFetch.start(); OX)#F'Sl}  
} )g9)IF  
catch(Exception e){e.printStackTrace ();} :(bdI]  
!paN`Fz\a  
lL:KaQ0E  
} L _vblUDq  
KjFZ  
+=ZWau   
public static void main(String[] args) '[>\N4WD  
{ bGZhUEq  
new TestMethod(); v%
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} qhV,u;\.  
} <Jwi~I=^  
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