http断点续传简单实现（java)

/* i7
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**SiteFileFetch.java '5V#sq;Z  
*/ k2axGq  
package NetFox; dF (m!P/R  
import java.io.*; Lc0yLm  
import java.net.*; xW
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public class SiteFileFetch extends Thread { Td|x~mZv:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean qYi<GI*|@  
long[] nStartPos; //开始位置 ;R#:? r;t  
long[] nEndPos; //结束位置 
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 @-g'BvS  
long nFileLength; //文件长度 k-~HUC.A.  
boolean bFirst = true; //是否第一次取文件 |izf|*e  
boolean bStop = false; //停止标志 LEM^8G]O  
File tmpFile; //文件下载的临时信息 pt
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DataOutputStream output; //输出到文件的输出流
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h3z=tu['  
public SiteFileFetch(SiteInfoBean bean) throws IOException $hCPmiI  
{ (l~3~n  
siteInfoBean = bean; @X\2K?c(v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W;^bc*a_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XyM?Dc5,  
if(tmpFile.exists ()) *,Mg  
{ Z T5p
 
bFirst = false; :zL.dJwa  
read_nPos(); 5[1#d\QR  
} y 8./)W&/  
else Q302!N  
{ |>Xw"]b;  
nStartPos = new long[bean.getNSplitter()]; ' YONRha  
nEndPos = new long[bean.getNSplitter()]; guD?~-Q  
} VB+sl2V<h  
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} ]:Q7Gys  
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public void run() kS>'6x
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{ OoFQ@zE7%  
//获得文件长度 $=97M.E  
//分割文件 kRk=8^."By  
//实例FileSplitterFetch @QAyXwp  
//启动FileSplitterFetch线程 Wu 71q=  
//等待子线程返回 x+O}RD*G  
try{ V zx%N.  
if(bFirst) KAg<s}gQJ  
{ [xXml On!  
nFileLength = getFileSize(); 6g ,U+~  
if(nFileLength == -1) $Xlyc.8YId  
{ ,{C(<1  
System.err.println("File Length is not known!"); GXEOgf#i  
} /WDz;,X  
else if(nFileLength == -2) cZRLYOC  
{ Y[Gw<1F_  
System.err.println("File is not access!"); RRD\V3C84  
} ^"w.v' sL  
else NLJD}{8Ot  
{ n7vLw7  
for(int i=0;i<nStartPos.length;i++) /D[GXX  
{ Bx&.Tj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J3sO%4sYR  
} YkcX#>,  
for(int i=0;i<nEndPos.length-1;i++) ;3n0 bKDY  
{ }*n(RnCn  
nEndPos = nStartPos[i+1]; 5L<}u`0J  
} ?=<vC  
nEndPos[nEndPos.length-1] = nFileLength; 6(4o}Sv  
} YbC6&_  
} &DX9m4,y  
kWfNgu$xK  
t|*PC  
//启动子线程  ?4 `K8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @j$t
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for(int i=0;i<nStartPos.length;i++) [Cz.K?+#M  
{ ~Exd_c9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1Tn!.E *  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); 3zb;q@JV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y+RT[*bX5o  
fileSplitterFetch.start(); VI%879Z\e  
} /Q"nQSG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M* W=v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o'Q)V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^zGgvFf>  
nEndPos = " + nFileLength); "7!K'i  
// fileSplitterFetch[nPos.length-1].start(); ]lF'o&v]  
jlER_I]  
:^SpKe(7  
//等待子线程结束 H^Xw<Z=  
//int count = 0; ( $3j  
//是否结束while循环 'uUp1+  
boolean breakWhile = false; v@k62@;
 
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while(!bStop) )2oWoZvi9  
{ |xH"Xvp:  
write_nPos(); J`O4]XRY  
Utility.sleep(500); 1!\!3xaV  
breakWhile = true; )J_!ZpMC  
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for(int i=0;i<nStartPos.length;i++) w\;=3C`  
{ ?ZSG4La\  
if(!fileSplitterFetch.bDownOver) &a8#qv"l  
{ I TJ>[c]x  
breakWhile = false; `sN3iD!@R  
break; w2~(/RgO  
} o lNL|WJ`w  
} UTUIL D  
if(breakWhile) G=3/PYp  
break; dv%gmUUf}k  
~GfcI:Zz&  
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//count++; -3VxjycY  
//if(count>4) VzpPopD,QW  
// siteStop(); V#!ypX]AB[  
} Ii*v(`2b  
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System.err.println("文件下载结束！"); 5vYh~|  
} "h7-nwm  
catch(Exception e){e.printStackTrace ();} hC]c =$=7  
} jjvm<;lv  
.,,?[TI  
5%?La`C9[  
//获得文件长度 P,iLqat  
public long getFileSize() )X\.Xr-6q  
{ 5DyN=[b  
int nFileLength = -1; 5G){7]P+r"  
try{ *^c4q|G.-  
URL url = new URL(siteInfoBean.getSSiteURL()); v!@/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ItKwB+my  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1elcP`N1  
]qXHalHY  
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int responseCode=httpConnection.getResponseCode(); )gR14a  
if(responseCode>=400) Lj(hk@  
{ )dF(5,y)  
processErrorCode(responseCode); A>>@&c:(  
return -2; //-2 represent access is error ]02 l!"  
} 1y0.tdI(  
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String sHeader; =JO|m5z8>  
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for(int i=1;;i++) PBn(k>=+  
{ (fh:q2E#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NFLmM  
//Utility.log(in.readLine()); UUb!2sO  
sHeader=httpConnection.getHeaderFieldKey(i); <mY`<(bc  
if(sHeader!=null) 83i%3[L  
{ N>ct`a)BD/  
if(sHeader.equals("Content-Length")) 5B2x# m|8  
{ bHS2;K~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K!I]/0L  
break; `yYgL@Zt  
} dN |w;|M  
} //ZB B,[@  
else GeHDc[7  
break; >+vWtO2  
} :1Fm~'  
} B"KsYB79t  
catch(IOException e){e.printStackTrace ();} *$#r%  
catch(Exception e){e.printStackTrace ();} 9d[0i#`:q  
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Utility.log(nFileLength); <u2*(BM4  
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return nFileLength; & p_;&P_  
} ` V^#Sb  
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//保存下载信息（文件指针位置） RX2= iO"  
private void write_nPos() "bf8[D  
{ n+Ag|.,|  
try{ <*(~x esPS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p+8]H %  
output.writeInt(nStartPos.length); 7vj[ AOq3l  
for(int i=0;i<nStartPos.length;i++) f6|3| +  
{ iU%Gvf^?'5  
// output.writeLong(nPos); !+hX$_RT  
output.writeLong(fileSplitterFetch.nStartPos); VpVw:Rh>  
output.writeLong(fileSplitterFetch.nEndPos); huKz["]z[  
} p*npY"}v  
output.close(); YSa:"A  
} "BFW&<1  
catch(IOException e){e.printStackTrace ();} [tD*\\IA  
catch(Exception e){e.printStackTrace ();} iBo-ANnK9  
} Uw&+zJ  
<q[*kr  
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//读取保存的下载信息（文件指针位置） ~:t2@z4p  
private void read_nPos() p\-.DRwT`  
{ oC7#6W:@w  
try{ _ZS<zQ'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A+F-r_]}db  
int nCount = input.readInt(); yPQ{tS*t  
nStartPos = new long[nCount]; q!ZmF1sU  
nEndPos = new long[nCount]; ]#:xl}'LS  
for(int i=0;i<nStartPos.length;i++) w x,;  
{ 1|. 0]~0  
nStartPos = input.readLong(); +z[!]^H]4  
nEndPos = input.readLong(); .<NXk"\!y  
} qFs<s<]  
input.close(); =~0XdS/1  
} YD
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catch(IOException e){e.printStackTrace ();} YKx0Zs  
catch(Exception e){e.printStackTrace ();} [Thz
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} hPk+vvXtK  
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private void processErrorCode(int nErrorCode) @B^'W'&C  
{ ]yIy~V  
System.err.println("Error Code : " + nErrorCode); wlpbfO e/  
} ):|)/ZiC'  
?Jr<gn^D  
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//停止文件下载 u?J(l)gd  
public void siteStop() CD tYj  
{ \)#3S $L~  
bStop = true; &qpA<F@7  
for(int i=0;i<nStartPos.length;i++) 3
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fileSplitterFetch.splitterStop(); 8/F2V?iT  
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} $U0(%lIU  
} MnS"M[y3  
//负责部分文件的抓取 @'rO=(-b  
**FileSplitterFetch.java % (.PRRI  
*/ 3PEs$m9e  
package NetFox; }GC{~ SZ4  
#rC/y0niH  
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import java.io.*; ibAA:I,d  
import java.net.*; d{trO;%#f  
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public class FileSplitterFetch extends Thread { v6n(<0:  
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String sURL; //File URL A+l"  
long nStartPos; //File Snippet Start Position s-ou;S3s  
long nEndPos; //File Snippet End Position A^Zs?<C-  
int nThreadID; //Thread's ID &p%ctg  
boolean bDownOver = false; //Downing is over K@,VR3y /  
boolean bStop = false; //Stop identical fE:2MW!)*  
FileAccessI fileAccessI = null; //File Access interface [5 V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <>:kAT,sP  
{ Xm-63U`w5  
this.sURL = sURL; zKutx6=aj  
this.nStartPos = nStart; 51,m^veO  
this.nEndPos = nEnd; Ii8jY_  
nThreadID = id; dkLR Q   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *,p
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} h`Mf;'P  
p(8\w-6  
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public void run() 7.t$#fzi  
{ wf4Q}l2,d  
while(nStartPos < nEndPos && !bStop) F)IP~BE-k  
{ Uoe?5Of(*  
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try{ f1{ckHAY55  
URL url = new URL(sURL); DIRCP=5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <f6Oj`{f4  
httpConnection.setRequestProperty("User-Agent","NetFox"); O`=Uq0Vv  
String sProperty = "bytes="+nStartPos+"-"; )?WoLEjq  
httpConnection.setRequestProperty("RANGE",sProperty); U_~~PCi  
Utility.log(sProperty); f,#xicSB*  
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InputStream input = httpConnection.getInputStream(); )'g vaT  
//logResponseHead(httpConnection); >xjy P!bca  
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byte[] b = new byte[1024]; T,fz/5w  
int nRead; z|2liQrf+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]3C8  
{ 'FhnSNT(4=  
nStartPos += fileAccessI.write(b,0,nRead); iiTUhO )  
//if(nThreadID == 1) ]*|K8&jxl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8f.La  
} ?1uAY.~ZZB  
O2e"TH3  
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Utility.log("Thread " + nThreadID + " is over!"); _biJch  
bDownOver = true; D/WS  
//nPos = fileAccessI.write (b,0,nRead); {JgN^R<5<f  
} OOCeZ3yF(
 
catch(Exception e){e.printStackTrace ();} &}cie"\L  
} DbN'b(+  
} (AYD@  
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//打印回应的头信息 H.L@]~AyL  
public void logResponseHead(HttpURLConnection con) `{Jb{L@f  
{ 0FOf *Lz  
for(int i=1;;i++) ?MH4<7?"  
{ )YFs  
String header=con.getHeaderFieldKey(i); 1%,Z&@^j  
if(header!=null) =+p+_}C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y6/X!+3+  
Utility.log(header+" : "+con.getHeaderField(header)); CkU=0mcY  
else : [y(<TLw  
break; m"R(_E5  
} g8Z14'Ke  
} Eg*3**gTO  
 Z-@}~#E  
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public void splitterStop() >$DqG$D  
{ `cpcO  
bStop = true; ZAZCvN@5  
} +$t%L  
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} }U9jsm  
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/* dK: "  
**FileAccess.java e`r;`a&  
*//文件访问(定位，写) {P&^Erx  
package NetFox;  o2  
import java.io.*; wY#mL1dF  
d]EvC>  
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public class FileAccessI implements Serializable{
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3;NRW+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7VcVI? ?  
RandomAccessFile oSavedFile; n^N]iw{G  
long nPos; M-N2>i#  
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public FileAccessI() throws IOException (, "E9.  
{ $8k_M   
this("",0); keskD  
} NrcCUZ .:N  
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public FileAccessI(String sName,long nPos) throws IOException \BXVWE|  
{ or}*tSKX  
oSavedFile = new RandomAccessFile(sName,"rw"); de9l;zF  
this.nPos = nPos; Z@!W?Ed  
oSavedFile.seek(nPos); I&8m5F?$`  
} I})
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#~;8#!X  
AF]!wUKxy  
public synchronized int write(byte[] b,int nStart,int nLen) @88i/ Z_  
{ Ky#B'Bh}`g  
int n = -1; t[hocl/6  
try{ on?/tHys  
oSavedFile.write(b,nStart,nLen); +E|ouFI  
n = nLen; 9^ p{/Io  
} |+-i'N9  
catch(IOException e) RWCS u$  
{ &pjV4m|j<  
e.printStackTrace (); ~aAJn IO  
} Y,btL'[W  
!"%sp6Wc  
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return n; o'/C$E4W  
} I^(#\vRW  
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} ?3TV:fx"X  
?VQLY=?  
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/* 
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**SiteInfoBean.java uhB!k-ir  
*/ n~u3  
package NetFox; J+jmSK%z  
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public class SiteInfoBean { P
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1Dp@n  
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private String sSiteURL; //Site's URL ;+34g6  
private String sFilePath; //Saved File's Path ^z}lGu  
private String sFileName; //Saved File's Name u#WTh%/  
private int nSplitter; //Count of Splited Downloading File 917 0bmr  
S?\hbM]V-o  
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public SiteInfoBean() QM_X2Ho  
{//nSplitter的缺省值为5 [ 5 2zta  
//default value of nSplitter is 5 P3tG#cJ  
this("","","",5); U!?gdX  
} 5}bZs` C  
D%UZ'bHN*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [[]SkLZHg  
{  G].__]  
sSiteURL= sURL; gT&'i(c  
sFilePath = sPath; #z!Hb&Qi\  
sFileName = sName; RB7AI!'a?  
this.nSplitter = nSpiltter; yISQYvSN  
)|y2Q  
L'XdX\5  
} |F@xwfgb  
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:q64K?X  
public String getSSiteURL() rp @  
{ RF~Ofi  
return sSiteURL; ^M"z1B]  
} bk"k&.C^+  
15
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public void setSSiteURL(String value) Fiu!!M6  
{ ;=+Zw1/g  
sSiteURL = value; ,ah*!Zm.kk  
} k l!?/M  
+6hl@Fm(  
.^~l_LkA  
public String getSFilePath() u}}9j&^Xa  
{ Z%5nVsm:G  
return sFilePath; g:DTVq  
} 4s~HfxYT  
#CA%]*l
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public void setSFilePath(String value) VP%i1|XZJ  
{ %7v@n+Q  
sFilePath = value; kg: uGP9  
} Fu4EEi  
5rmlAq  
t'Eb#Nup3  
public String getSFileName() S6T!qH{6  
{ 7AO3-; l]  
return sFileName; ]oeuIRyQ  
} hB7pR"P  
^0~c7`k`V  
!/6\m!e|1R  
public void setSFileName(String value) TD{=L*{+  
{ 2:iYYRrg  
sFileName = value; inPE/Ux  
} wD6!#t k  
|O(-CDQe  
yS)-&t!;  
public int getNSplitter() w}j6.r  
{ i}`_H^  
return nSplitter; j!x<QNNX  
} J-tq8
   
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hD6JW-  
public void setNSplitter(int nCount) L$lo~7<]  
{ tS (i711  
nSplitter = nCount; 6h2x
~@  
} t{Hh&HX  
} 9^PRX  
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1Y=AT!"V  
/* ',sQ/#S  
**Utility.java xvR?~  
*/ z1f^p7$M?  
package NetFox; |^Ew<
  
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public class Utility { Ht|",1yr+  
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Gefnk!;;  
public Utility() 3}B5hht"D  
{ hdd>&?p3  
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} D3S+LV  
-9OMn}w/*  
//线程睡眠 (Qk&g"I  
public static void sleep(int nSecond) [,O`MU  
{ !Ea&]G  
try{ cBifZv*l  
Thread.sleep(nSecond); bQwdgc),s{  
} L$1K7<i.  
catch(Exception e) "xvtqi,R  
{ m~u|VgD  
e.printStackTrace (); aKv[  
} 50LHF%  
}
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)=jT_?9b   
//日志 908ayfVI  
public static void log(String sMsg) e'1 ^+*bU  
{
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System.err.println(sMsg); 3ppuQQ  
} yS[z2:!  
;/@?6T"  
g/IH|Z=A  
public static void log(int sMsg) w]};0v&\~s  
{ g4N%PV8  
System.err.println(sMsg); WP0 #i~3*  
} la'e[t7  
} Z#-k.|}  
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\F 3C=M@:  
/* M#OHY*  
**TestMethod.java /Q?~Q0{)es  
*/ =/6p#d*0  
package NetFox; M^z=1YrMd  
i?F[||O"$  
=~J
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public class TestMethod { Ovvny$  
XtCoX\da  
%_R$K#T^,  
public TestMethod() *(k%MTG  
{ ///xx/weblogic60b2_win.exe i"L}!5  
try{ QU:EY'2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pT4qPta,2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q@w{c=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1g1?zk8zO  
fileFetch.start(); 4P|$LkI  
} 6|,e%  
catch(Exception e){e.printStackTrace ();} <tFSF%vG=  
um;:fT+  
>SvDgeg_7f  
} }6).|^]\'  
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public static void main(String[] args) s=MT,  
{ -b cG[W3  
new TestMethod(); k, f)2<  
} <EtUnj:qK8  
}  ]nUR;8  
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