http断点续传简单实现（java)

/* $EdL^Q2KAy  
**SiteFileFetch.java XQOM6$~,  
*/ }:s.m8LC5n  
package NetFox; Xe\v6gbD  
import java.io.*; #Hl?R5  
import java.net.*; <|E*aR|M  
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public class SiteFileFetch extends Thread { m3(p7Z^Bq  
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SiteInfoBean siteInfoBean = null; //文件信息Bean SoFl]^l  
long[] nStartPos; //开始位置 [CAFh:o  
long[] nEndPos; //结束位置 r0pwKRE~t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0hXx31JN N  
long nFileLength; //文件长度 >I;.q|T  
boolean bFirst = true; //是否第一次取文件 SC3_S.  
boolean bStop = false; //停止标志 d<m.5ECC}  
File tmpFile; //文件下载的临时信息 SUvrOl   
DataOutputStream output; //输出到文件的输出流 yKz%-6cpSl  
S`TQWWQo;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y M-k]_  
public SiteFileFetch(SiteInfoBean bean) throws IOException CFoR!r:X  
{ r&F 6ZCw  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n7/&NiHxv/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >$a;+v  
if(tmpFile.exists ()) g<$2#c}  
{ I;UT;/E2  
bFirst = false; }YM[aq?6  
read_nPos(); m G+=0Rn^  
} CZ{7?:^f  
else ^/}&z  
{ {DUtdu[  
nStartPos = new long[bean.getNSplitter()]; u&o$2 '8  
nEndPos = new long[bean.getNSplitter()]; +A$>F@u  
} *q[;-E(fZ#  
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} bV"t;R9  
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public void run() Otf{)f  
{ s5*HS3D  
//获得文件长度 }iUpBn  
//分割文件 fILvEf4b  
//实例FileSplitterFetch Zdfh*MHMg  
//启动FileSplitterFetch线程 B;piO-hH  
//等待子线程返回 #veV {,g  
try{ &zP>pQr`#  
if(bFirst) %E [HMq<H  
{ U: )Gc  
nFileLength = getFileSize(); q_9 tbZ;  
if(nFileLength == -1) Wu$yB!  
{ V"}Jsr  
System.err.println("File Length is not known!"); )ac!@slb^7  
} +NiCt S  
else if(nFileLength == -2) |TR
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{ @:>gRD  
System.err.println("File is not access!"); qmvQd8|XR  
} N\rL ~4/  
else (I35i!F+tY  
{ 47f\  
for(int i=0;i<nStartPos.length;i++) @*|T(068&  
{ 3od16{YH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NBLjBa%eL  
} -YrMVoZl  
for(int i=0;i<nEndPos.length-1;i++) Oi-%6&}J  
{ [Q/kNK  
nEndPos = nStartPos[i+1]; XBO( *6"E  
} <num!@2D  
nEndPos[nEndPos.length-1] = nFileLength; nI1(2a1  
} :l?mNm5  
} Bx5kqHp^1  
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//启动子线程 L1y71+iqU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vobq|Rd/%  
for(int i=0;i<nStartPos.length;i++) <vD(,||  
{ ,@Kn@%?$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hk(=_[S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kJNwA8 7  
nStartPos,nEndPos,i); h@y>QhYU0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \wK4bv
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fileSplitterFetch.start(); VYt<j<ba  
} m^,VEV>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TZ!@IBu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |>.</68Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o
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nEndPos = " + nFileLength); GJs~aRiz  
// fileSplitterFetch[nPos.length-1].start(); (vvD<S*  
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//等待子线程结束  nb6Y/`G  
//int count = 0; KeXt"U  
//是否结束while循环 n1:q:qMR1  
boolean breakWhile = false; _aJKt3GQ  
#3'M>SaoH  
}d;6.~Gw  
while(!bStop) <iGW~COd  
{ jp^Sw|  
write_nPos(); l"jYY3N|h  
Utility.sleep(500); )}t't"  
breakWhile = true; L' bY,D(J>  
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for(int i=0;i<nStartPos.length;i++) Fop +xR,Z  
{ ,LxkdV  
if(!fileSplitterFetch.bDownOver) TU*EtE'
g/  
{ IOY7w"|LW  
breakWhile = false; /SQ/$`1{  
break; WIpV'F|t]`  
} %qTIT?6'  
} 6<R[hIWpZ}  
if(breakWhile) 5NH4C  
break; nj0]c`6rN@  
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//count++; 5C^@w
 
//if(count>4) I3d}DpPx%  
// siteStop(); $$"G1<EZ  
} +%u3% }  
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System.err.println("文件下载结束！"); 6 .)Xeb"  
} dM P'Vnfj  
catch(Exception e){e.printStackTrace ();} CH;U_b  
} ^w2 HF  
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//获得文件长度 Ym!e}`A\F  
public long getFileSize() Eh|,[D!E  
{ Xtz:^tg  
int nFileLength = -1; ~id:Rh>o  
try{ _L$a[zH  
URL url = new URL(siteInfoBean.getSSiteURL()); 2CneR
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i. (Af$  
httpConnection.setRequestProperty("User-Agent","NetFox"); $(]nl%<Q  
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int responseCode=httpConnection.getResponseCode(); ' VKD$q  
if(responseCode>=400) KB(W'M_D\  
{ :Jv5Flxl  
processErrorCode(responseCode); NY.*
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return -2; //-2 represent access is error ~(kqq#=s  
} o[fg:/5)A  
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String sHeader; hqmE]hwc  
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for(int i=1;;i++) .kn2M&P>=  
{ a#;;0R $  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |5O>7~Tp  
//Utility.log(in.readLine()); $~W5! m  
sHeader=httpConnection.getHeaderFieldKey(i); }u=Oi@~  
if(sHeader!=null) ^2+Vt=*  
{ .9PT)^2  
if(sHeader.equals("Content-Length")) *kg->J  
{ |iUC\F=-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a.}#nSYP  
break; {\P%J:s#9  
} 0doJF@H  
} UeLO`Ug0;  
else QuPz'Ut#  
break; i/1$uQ  
} >7%T%2N  
} yNP4Ey  
catch(IOException e){e.printStackTrace ();} nReld :#T  
catch(Exception e){e.printStackTrace ();} vZ"gCf3#?3  
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Utility.log(nFileLength); *Q/^ib9=  
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return nFileLength; t'@mUX:-A  
} G2)F<Y  
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//保存下载信息（文件指针位置） :TG;W,`.V  
private void write_nPos() k_7b0dr%F  
{ 40h$- VYT/  
try{ fs&$?mHL){  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -P/DmSS8V  
output.writeInt(nStartPos.length); Q47R`"  
for(int i=0;i<nStartPos.length;i++) h-?yed*?  
{ jqc}mI\#  
// output.writeLong(nPos); ,}gJY^X+  
output.writeLong(fileSplitterFetch.nStartPos); 6&ut r!\7  
output.writeLong(fileSplitterFetch.nEndPos); 5)lcgvp  
} 1p$(\
 
output.close(); 5P"R'/[PA_  
} kaB|+U9^  
catch(IOException e){e.printStackTrace ();} ,.>9$(s  
catch(Exception e){e.printStackTrace ();} C9sU^]#F  
} WcNQF!f  
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//读取保存的下载信息（文件指针位置） M-Efe_VRQc  
private void read_nPos() L%is"NZh  
{ >RkaFcq  
try{ 9$;5J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -oyA5Yx0  
int nCount = input.readInt(); rSJ!vQo Cb  
nStartPos = new long[nCount]; t:fz%IOe  
nEndPos = new long[nCount]; fJc(  
for(int i=0;i<nStartPos.length;i++) O8A1200  
{ f(D'qV T{  
nStartPos = input.readLong(); uH%b rbrU  
nEndPos = input.readLong(); RBn/7  
} h]ae^M  
input.close(); L,y q=%h|  
} (4/"uj5  
catch(IOException e){e.printStackTrace ();} $Z#~wsw  
catch(Exception e){e.printStackTrace ();} }%/mPbd#  
} 8:V,>PH  
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private void processErrorCode(int nErrorCode) 6dr
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{ \EVT*v=}/  
System.err.println("Error Code : " + nErrorCode); x,25ROaHY  
} jeRE(3'Q  
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//停止文件下载 >B**fZ~L  
public void siteStop() .eD&UQ  
{ )LFbz#;Y  
bStop = true; I!*P' {lh  
for(int i=0;i<nStartPos.length;i++) B]G2P`sN  
fileSplitterFetch.splitterStop(); "gM!/<~  
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} |nx3x  
} xz!0
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//负责部分文件的抓取 w)+1^eW  
**FileSplitterFetch.java xB Wl|j  
*/ <$z[pw<  
package NetFox; #C&';HB;y  
s_NY#MPz[  
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import java.io.*; '2lzMc>wvP  
import java.net.*; 9m$"B*&6G  
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public class FileSplitterFetch extends Thread { 6)uBUM;i  
<|_>r`@%l  
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String sURL; //File URL `KA==;0  
long nStartPos; //File Snippet Start Position $5 mGYF]  
long nEndPos; //File Snippet End Position u'l4=e  
int nThreadID; //Thread's ID SqPqL<,e  
boolean bDownOver = false; //Downing is over ?g+3 URpK  
boolean bStop = false; //Stop identical lz#.f,h  
FileAccessI fileAccessI = null; //File Access interface 7gf(5p5ZV  
+ m-88  
#ay/VlD@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yl~;!  
{ _D{A`z  
this.sURL = sURL; hb3:,c(  
this.nStartPos = nStart; g@>llve{  
this.nEndPos = nEnd; G|Et'k.F4  
nThreadID = id; u.X]K:Yow  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #wIWh^^ Zy  
} u>lt}0  
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public void run() z)C/U  
{ md+pS"8o;  
while(nStartPos < nEndPos && !bStop) Ct)58f2  
{ "D.<~!  
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try{ hO8xH +;  
URL url = new URL(sURL); 1<_][u@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1(BLdP3&  
httpConnection.setRequestProperty("User-Agent","NetFox"); /io06)-/n  
String sProperty = "bytes="+nStartPos+"-";  N~$>| gn  
httpConnection.setRequestProperty("RANGE",sProperty); Y`j$7!j  
Utility.log(sProperty); L'{W|Xb+  
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InputStream input = httpConnection.getInputStream(); 8C*@d_=q  
//logResponseHead(httpConnection); WBWW7
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byte[] b = new byte[1024]; p\=T#lb  
int nRead; uG7]s]Wdz;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $f3IO#N  
{ <)T| HKx  
nStartPos += fileAccessI.write(b,0,nRead); ?3BcjD0  
//if(nThreadID == 1) o@L0ET  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} #b;?:.m\=  
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Utility.log("Thread " + nThreadID + " is over!"); Mrrpm%Y  
bDownOver = true; sr;&/l#7h  
//nPos = fileAccessI.write (b,0,nRead); >ZOlSLu  
} 5m~9Vl-&  
catch(Exception e){e.printStackTrace ();} $XQgat@&]  
} \09A"fs{  
} fVn4=d6X  
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~NK $rHwi%  
//打印回应的头信息 rlKR <4H  
public void logResponseHead(HttpURLConnection con) j<(E%KN3  
{ 0V<kpC,4  
for(int i=1;;i++) kMVr[q,MEq  
{ O`y3H lc  
String header=con.getHeaderFieldKey(i); GLO3v. n;  
if(header!=null) -b^dK)wR~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >} 2C,8N  
Utility.log(header+" : "+con.getHeaderField(header)); ys=} V|  
else D?_K5a&v,  
break; "G@K(bnHn  
} eB#I-eD  
} qg#YQ'vWte  
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public void splitterStop() {BJ>x:2  
{ ir}z^+  
bStop = true;
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} &qg6^&  
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} .@)vJtH)  
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/* :L@;.s  
**FileAccess.java ~o_JZ:  
*//文件访问(定位，写) O;RBK&P  
package NetFox; j#p;XI  
import java.io.*; r&8aB85  
nBk&+SN  
rNV3-#kU  
public class FileAccessI implements Serializable{ 5c::U=  
*90dkJZ.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hdw.S`~}%  
RandomAccessFile oSavedFile; #l}Fk
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long nPos; ljK?2z>  
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public FileAccessI() throws IOException qj~=qV0p  
{ OS#aYER~/  
this("",0); >G|RVB  
} F6sQeU  
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FcM)v"bF&]  
public FileAccessI(String sName,long nPos) throws IOException 1?&|V1
vc  
{ eXKEx4rU  
oSavedFile = new RandomAccessFile(sName,"rw"); ;j1 SSHZ  
this.nPos = nPos; ;av!fK  
oSavedFile.seek(nPos); F3(SbM-  
} *>W<n1r@]  
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public synchronized int write(byte[] b,int nStart,int nLen) r =x"E$  
{ BO*)cLQ  
int n = -1;
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try{ Yd4X*Ua  
oSavedFile.write(b,nStart,nLen); =7}1NeC`  
n = nLen; iHNQxLkk{:  
} (UkDww_!  
catch(IOException e) hiVa\s  
{ ({rcH.:  
e.printStackTrace (); ]^"Lc~w8&  
} }Ecv6&G  
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return n; g "Du]_,  
} uEb:uENk'(  
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} &UH0Tw4   
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/* 2?7ID~\  
**SiteInfoBean.java K@=u F1?  
*/ pv0|6X?J"  
package NetFox; }+m4(lpl  
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public class SiteInfoBean { >/\TG8t,f  
Crc6wmp  
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private String sSiteURL; //Site's URL aR3jeB,=x  
private String sFilePath; //Saved File's Path MuWZf2C  
private String sFileName; //Saved File's Name czIEkm  
private int nSplitter; //Count of Splited Downloading File wA$?e}  
7HW:;2dL  
>8{w0hh;  
public SiteInfoBean() ~"%'(j_4  
{//nSplitter的缺省值为5 ggPGKY-b=  
//default value of nSplitter is 5 &*/= `=:C8  
this("","","",5); =b*GV6b  
} h'S0XU ;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) bp'%UgA)1  
{ =KQIrS:  
sSiteURL= sURL; SM)"vr_  
sFilePath = sPath; 69$R.  
sFileName = sName; EE]xZz>o  
this.nSplitter = nSpiltter; 1/mBp+D  
>[wxZ5))  
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} `\(co;:  
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public String getSSiteURL() }J
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{ O-7)"   
return sSiteURL; TI8\qIW  
} 5yt=~  
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j7E;\AZ^  
public void setSSiteURL(String value) vKW!;U9~P  
{ k(Xs&f `  
sSiteURL = value; ^`#7(S)a/  
} Y.I~.66s  
rr
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public String getSFilePath() .BxQF  
{ 6, j60`f)  
return sFilePath;  kVZs:  
} Qa/1*Mb  
Da)p%E>Q  
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public void setSFilePath(String value) $W}:,]hoj  
{ JcYY*p  
sFilePath = value; #QsJr_=  
} {.oz^~zs]g  
u
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public String getSFileName() 5q@s6_"{  
{ eb}XooX  
return sFileName; PdVY tK%  
} f%n ;Z}=  
;\}dQsX  
}>AA[ba"'  
public void setSFileName(String value) |8{ k,!P'K  
{ ;yqHt!N  
sFileName = value; cg^~P-i@*  
} "4xo,JUf  
.= ~2"P  
=/j!S|P  
public int getNSplitter() /Bgqf,N |  
{ ?IQDk|<%  
return nSplitter; v B~VJKD  
} !oi {8X@  
0?t;3z$n  
ye(av&Hn  
public void setNSplitter(int nCount) ;=@O.iF;H  
{ unFm~rcf  
nSplitter = nCount; C8v  
} zQO 1%g  
} bZUw^{~)D  
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dm"x?[2:  
/* f uU"  
**Utility.java l#]#_  
*/ xc-[gt6  
package NetFox; Qt\:A!'jw  
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public class Utility { ^PE|BCs  
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yz,_\{}  
public Utility() L;g2ZoqIr0  
{ ^-Arfm%dn  
)(.g~Q:  
8cvSA&l(D  
} 0iC5,  
1,zc8>M  
//线程睡眠 P()n=&XO6  
public static void sleep(int nSecond) 9MJ:]F5+  
{ @6|0H`kv  
try{ pUmT?N!  
Thread.sleep(nSecond); h5@7@w%
 
} +>eX1WoTy  
catch(Exception e) LZG(T$dI  
{ !s$1C=z5u  
e.printStackTrace (); b^<7a&  
} r91i :  
} f6SXXkO+  
zV15d91GX  
//日志 /W f.Gt9[  
public static void log(String sMsg) r$M<vo6C  
{ &xUCXj2-z  
System.err.println(sMsg); Wn=I[K&&  
} t:oq'
t  
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H
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public static void log(int sMsg) FmF[S&gFRs  
{ #~m^RoE  
System.err.println(sMsg); Exv!!0Cd^  
} iu{;|E  
} WC_U'nTu4  
AK'3N1l`  
m=COF$<  
/* 3qu?qD  
**TestMethod.java ">8oF.A^  
*/ Z/GSR$@lI  
package NetFox; dEkST[Y3  
3 %r*~#nz  
o&k,aCQC  
public class TestMethod { .*595SuF  
#ax% n  
zmuRn4Nv  
public TestMethod() hWn-[w/l_  
{ ///xx/weblogic60b2_win.exe Y>E` 7n  
try{ f
2KH&j>~r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c9nv=?/}f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )FA:
wsy~E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FW3E UC)P  
fileFetch.start(); Xfb-< Q0A  
} i8cmT+}>  
catch(Exception e){e.printStackTrace ();} 'tQp&pj  
e<A>??h^  
}43qpJe8U  
} ox.kL  
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public static void main(String[] args) >x~Qa@s;  
{ pfl^GgP#  
new TestMethod(); XfIsf9  
} #{k+^7aQ  
} cj2^wmkB  
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