http断点续传简单实现（java)

/* ,>-Q#  
**SiteFileFetch.java rTJv>Jjld  
*/ _H#l&bL@C  
package NetFox; -OLXRc=  
import java.io.*; SZ+<0Y|  
import java.net.*; }Ip"j]h  
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public class SiteFileFetch extends Thread { Bsm>^zZ`YU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean BV=L.*  
long[] nStartPos; //开始位置 k^A Yg!~  
long[] nEndPos; //结束位置 Y~=]RCg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g=?KpI-pn0  
long nFileLength; //文件长度 )3i}(h0  
boolean bFirst = true; //是否第一次取文件 r.e,!Bs
 
boolean bStop = false; //停止标志 o6e6Jw  
File tmpFile; //文件下载的临时信息 PPCZT3c=  
DataOutputStream output; //输出到文件的输出流 }`/wj  
@Yua%n6]#D  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,j~R ^j  
public SiteFileFetch(SiteInfoBean bean) throws IOException tMaJ; 4  
{ H~~I6D{8  
siteInfoBean = bean; qlUYu"`i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +NRn>1]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZIAiVq2)  
if(tmpFile.exists ()) {aq\sf;i{  
{ G+=6]0HT  
bFirst = false; 5*1wQlL  
read_nPos(); ~Z5?\a2Ld  
} NF=FbvNe  
else 1Oo^  
{ d#T8|#O"  
nStartPos = new long[bean.getNSplitter()]; pt8X.f,iA  
nEndPos = new long[bean.getNSplitter()]; r;w_B%9  
} YgaJ*%\  
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} {xt<`_R  
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public void run() @M4~,O6-  
{ ,TU!W|($  
//获得文件长度 sTqy-^e7  
//分割文件 32:,g4!~6  
//实例FileSplitterFetch bWv6gOPR3  
//启动FileSplitterFetch线程 qce#  
//等待子线程返回 l1c&a[M)  
try{ xy$FS0u  
if(bFirst) ^e8R43w:!  
{ "}K/ b  
nFileLength = getFileSize(); UA,&0.7  
if(nFileLength == -1) ?w# >Cs(  
{  wB5zp  
System.err.println("File Length is not known!"); oKt<s+r  
} UVu"meZX  
else if(nFileLength == -2) *wp'`3y}  
{ N(&FATZUW  
System.err.println("File is not access!"); 4PiNQ'*  
} T-&CAD3 ,O  
else 2xe_Q70II  
{ OJ UM Y<5  
for(int i=0;i<nStartPos.length;i++) EhB9M!Y`@  
{ G !1- 20  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }(E6:h;}~  
} ~J<bwF  
for(int i=0;i<nEndPos.length-1;i++) wt2S[:!p  
{ o9wg<LP  
nEndPos = nStartPos[i+1]; Z55,S=i  
} *BXtE8 BU  
nEndPos[nEndPos.length-1] = nFileLength; @hzQk~Gdi  
} T|.Q81.NE  
} ? |8&!F  
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//启动子线程 X""'}X|O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2Fx<QRz  
for(int i=0;i<nStartPos.length;i++) =_":Z!_  
{ Y ga}8DU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LOnh
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2)j\Lg_M  
nStartPos,nEndPos,i); 1r~lh#_8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {Y/|7Cl0  
fileSplitterFetch.start(); 3]N}k|lb%  
} c6c^9*,V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~7 `x9MUc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~|uCZ.;o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $,aU"'D  
nEndPos = " + nFileLength); fykN\b  
// fileSplitterFetch[nPos.length-1].start(); ,6M-xSDs  
g~B@=R  
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//等待子线程结束 h.?[1hT4R  
//int count = 0; /t>o -  
//是否结束while循环 UkqLLzL  
boolean breakWhile = false; LV]\{'  
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tjd"05"@:  
while(!bStop) 6\TstY3  
{ Nb];LCx  
write_nPos(); .oK7E(QJ  
Utility.sleep(500); 8PEOi  
breakWhile = true; cEqh|Q  
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for(int i=0;i<nStartPos.length;i++) x.^vWka(  
{ RChY+3,L)  
if(!fileSplitterFetch.bDownOver) 6sZRR{'  
{ 9~; Ju^b  
breakWhile = false; .|aSGvE  
break; L3GJq{t  
} GDcV1$NA  
} 6AwnmGL(;;  
if(breakWhile) }w-`J5Eq#  
break; WuNu}Ibl}m  
h7y*2:l6  
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//count++; <+$S{Z.  
//if(count>4) &*yve}su  
// siteStop(); uc<@ Fh(  
} 7 %|>7  
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System.err.println("文件下载结束！"); nB]Q^~jX  
} )KuvG:+9W  
catch(Exception e){e.printStackTrace ();} :RQ[(zD]  
} YHA[PF   
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//获得文件长度 &7W6IM  
public long getFileSize() {S}@P~H=  
{ 1CM1u+<iZ  
int nFileLength = -1; y2U:( H:l!  
try{ L[bGO|O  
URL url = new URL(siteInfoBean.getSSiteURL()); S|J8:-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wtUG2 (  
httpConnection.setRequestProperty("User-Agent","NetFox"); \nHlI=!P  
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int responseCode=httpConnection.getResponseCode(); uUe\[-~  
if(responseCode>=400) +o3g]0  
{ J50 ~B3bj`  
processErrorCode(responseCode); _tk5?9Ykn  
return -2; //-2 represent access is error U %ESuq#  
} DPwSg\*)  
TUaK:*x*  
q KM]wu0Et  
String sHeader; *X\c $=*  
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for(int i=1;;i++) (<l2 ^H  
{ 6.|~~/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _}&]`,s>  
//Utility.log(in.readLine()); nIjQLx  
sHeader=httpConnection.getHeaderFieldKey(i); p4'"Wk8  
if(sHeader!=null) !Ia"pNDf  
{ _@N)]!\MgP  
if(sHeader.equals("Content-Length")) ;}~=W!yz  
{ !_9$[Oq~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  YBD{l  
break; 8zC k9&  
} 5E!m! nBZ  
} .( h$@|Y  
else <L~xR5  
break; x+cF1N2.  
} |T_Pz&-  
} |y%].y)  
catch(IOException e){e.printStackTrace ();} rcZ SC3  
catch(Exception e){e.printStackTrace ();} 2?T:RB}  
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$ rYS  
Utility.log(nFileLength); o#xg:m_py  
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return nFileLength; Sx)Il~ x  
} kI3zYD^:  
`4H9f&8(  
6I.mc  
//保存下载信息（文件指针位置） r0deBRM  
private void write_nPos() [ 5W#1 &  
{ %^=!s  
try{ ph?
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output = new DataOutputStream(new FileOutputStream(tmpFile)); h.$__Gs  
output.writeInt(nStartPos.length); J,G9m4Z7  
for(int i=0;i<nStartPos.length;i++) +MZO%4  
{ J7ekIQgR  
// output.writeLong(nPos); `4.sy +2  
output.writeLong(fileSplitterFetch.nStartPos); AC:s4iacC  
output.writeLong(fileSplitterFetch.nEndPos); CQHp4_  
} (oitC
IV  
output.close(); U|7Qw|I7  
} ^:!(jiH  
catch(IOException e){e.printStackTrace ();} Hu9R.[u  
catch(Exception e){e.printStackTrace ();} Q 95
 
} oPu|Q^I=  
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//读取保存的下载信息（文件指针位置） /QXs-T}d  
private void read_nPos() zt)PZff/YQ  
{ s`iNbW="  
try{ xbrmPGpW$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '<D`:srV  
int nCount = input.readInt(); |5IY`;+9  
nStartPos = new long[nCount]; N9=r#![>,  
nEndPos = new long[nCount]; 8gtCY~m  
for(int i=0;i<nStartPos.length;i++) Xc2B2c  
{ Kt90mA  
nStartPos = input.readLong(); oiv2rOFu  
nEndPos = input.readLong(); 0"
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} ju^"vw  
input.close(); "26B4*  
} ;WS7.  
catch(IOException e){e.printStackTrace ();} `,-
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catch(Exception e){e.printStackTrace ();} +:"6`um|  
} %V%#y $l  
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private void processErrorCode(int nErrorCode) )YnI!v2T  
{ PF'5z#] NP  
System.err.println("Error Code : " + nErrorCode); E7yf[/it  
} SfZ=%6b7  
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n.a=K2H:V  
//停止文件下载 CFBUQMl>  
public void siteStop()  bL'#  
{ {wpMg  
bStop = true; A)RI:?+  
for(int i=0;i<nStartPos.length;i++) 6>=-/)p}  
fileSplitterFetch.splitterStop(); Z9"{f)T  
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} 8tV=fSHd  
} t*Vao  
//负责部分文件的抓取 npO@Haw  
**FileSplitterFetch.java ~Q_)>|R2  
*/ hB P$9GR  
package NetFox; E?Qz/*'zv  
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import java.io.*; yhSk"e'G  
import java.net.*; W(&Go'9e"  
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public class FileSplitterFetch extends Thread { -
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String sURL; //File URL 79{.O`v  
long nStartPos; //File Snippet Start Position K-2o9No?j`  
long nEndPos; //File Snippet End Position 0<]$v"`I  
int nThreadID; //Thread's ID )g9)IF  
boolean bDownOver = false; //Downing is over }[>RxHd  
boolean bStop = false; //Stop identical $z2xZqe  
FileAccessI fileAccessI = null; //File Access interface 6\,DnO   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qs6Nb'JvQR  
{ }mKGuCoH>  
this.sURL = sURL; ~/j$TT"  
this.nStartPos = nStart; qhV,u;\.  
this.nEndPos = nEnd; 5nMkd/  
nThreadID = id; 3)6+1Yc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ki;!WhF~  
} V*6l6-y~Ih  
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public void run() =dgo!k  
{ u iBl#J Q  
while(nStartPos < nEndPos && !bStop) 6uu^A9x  
{ Z{Vxr*9oO  
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try{ ~A^E  
URL url = new URL(sURL); zWy ,Om8P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NFB*1_m  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8K|J:[7  
String sProperty = "bytes="+nStartPos+"-"; $T"h";M)s  
httpConnection.setRequestProperty("RANGE",sProperty); &}v
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Utility.log(sProperty); C1h#x'k  
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InputStream input = httpConnection.getInputStream(); _,DO~L  
//logResponseHead(httpConnection); mbF(tSy  
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byte[] b = new byte[1024]; ,%A)"doaG  
int nRead; znt)]>f#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *%:@ cbF-M  
{ inYM+o!Ub  
nStartPos += fileAccessI.write(b,0,nRead); Z
+NF(d  
//if(nThreadID == 1) Dt W*n1Bt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Hu d|n  
} `q%U{IR  
q<n[.u1@  
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Utility.log("Thread " + nThreadID + " is over!"); (@+h5@J[`I  
bDownOver = true; vwVVBG;t  
//nPos = fileAccessI.write (b,0,nRead); %Nj #0YF]  
} NeHx2m+  
catch(Exception e){e.printStackTrace ();} #;`Oj  
} a>U6Ag<  
} I6+2>CUGo  
^pj>9%  
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//打印回应的头信息 _l<mu?"  
public void logResponseHead(HttpURLConnection con) &M[MEO`t8  
{ cQX:%Ix=  
for(int i=1;;i++) N&"QKd l  
{ flP>@i:e6  
String header=con.getHeaderFieldKey(i); mwIk^Sz]@  
if(header!=null) Axlm<3<wf"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q]TqI' o  
Utility.log(header+" : "+con.getHeaderField(header)); FqwIJ|ct  
else L?
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break; 'G8 ?'u_)  
} {SJsA)9:#  
} Rv<L#!; t  
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public void splitterStop() qEQAn/&  
{ B!}BM}r  
bStop = true; tw<P)V\h  
} -(9O6)Rs$  
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} F;P5D<  
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/* IE;\7r+h  
**FileAccess.java Ns<?b;aK  
*//文件访问(定位，写) &RW`W)
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package NetFox; =IZ[_ /@  
import java.io.*; cKjRF6w  
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public class FileAccessI implements Serializable{ XQ?fJWLU  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N*_"8LIfi_  
RandomAccessFile oSavedFile;
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long nPos; d>|;f  
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public FileAccessI() throws IOException _Yq@FOu  
{ ~}Z'0W)Q`z  
this("",0); 8sg|MWSU  
} E^wyD-ii/  
g)R1ObpZ  
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public FileAccessI(String sName,long nPos) throws IOException ~
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{ ,lm=M5b  
oSavedFile = new RandomAccessFile(sName,"rw"); $UvPo0{  
this.nPos = nPos; c}-(.eu  
oSavedFile.seek(nPos); :(,mL2[  
} $a(`ve|  
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|^( M{  
public synchronized int write(byte[] b,int nStart,int nLen) O/b+CSS1  
{ F!yV8XQ  
int n = -1; ?S ts
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try{ Sh&PNJ
-*  
oSavedFile.write(b,nStart,nLen); gXy-Mpzp  
n = nLen; U|5-0u5  
} pC(sS0J  
catch(IOException e) .=c<>/ 0  
{ 80;n|nNB  
e.printStackTrace (); vH[Pb#f-  
} (= ;N{u  
?*u*de[,  
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return n; wtH~-xSB|  
} qCPmbg  
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} 9 OT,TpA  
:/N+;- 18  
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/* s'\$t  
**SiteInfoBean.java Z(GfK0vU
 
*/ UE"GJt`I  
package NetFox; ,wAz^cK|  
o{WyQ&2N  
!L24+$  
public class SiteInfoBean { YY5!_k  
hdma=KqZ(  
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private String sSiteURL; //Site's URL ZH 6\><My  
private String sFilePath; //Saved File's Path 7h9U{4r: M  
private String sFileName; //Saved File's Name q_[G1&MC  
private int nSplitter; //Count of Splited Downloading File ('[TLHP  
# Su~`]  
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public SiteInfoBean() /)3Lnn
{W  
{//nSplitter的缺省值为5 f 2YLk  
//default value of nSplitter is 5 (eWPis[  
this("","","",5); \cJa;WM>  
} MXtkP1A`  
2?q(cpsN  
9i q""  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aHzHvl  
{ 0Q5^C!K  
sSiteURL= sURL; jM)C4ii.-$  
sFilePath = sPath; ~FU@wV^  
sFileName = sName; 1GCzy
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this.nSplitter = nSpiltter; {Qu"%h.Al  
;q>9W,jy  
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} ]; $] G-  
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public String getSSiteURL() ?/hZb"6W  
{ eGL1  
return sSiteURL; !^c@shLN4  
} ^Q<mV*~  
4'1m4Ugg  
OX]V)QHVZ  
public void setSSiteURL(String value) &DG->$&|  
{ T#@lDpO  
sSiteURL = value; I{'f|+1  
} KL,/2(  
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public String getSFilePath() jhgX{xc  
{ K6JVg$  
return sFilePath; Ga>uFb}W~  
} @&F@I3`{  
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public void setSFilePath(String value) ? 8aaD>OR$  
{ m><w0k?t  
sFilePath = value; .jw}JJ  
} Yj|eji7y  
/&#XhrT  
 +ECDD'^!  
public String getSFileName() ^jB8Q  
{ ocbB&  
return sFileName; Jq.lT(E8D  
} f"u*D,/sS  
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}T^cEfX  
public void setSFileName(String value) '7Nr8D4L  
{ lASL8O&\  
sFileName = value; J&/lx${  
} $0oO &)*  
d,vNem-Z*L  
AmPMY:1i"  
public int getNSplitter() \6?A!w~6  
{ []R? ViG  
return nSplitter; \@3Qi8u//  
} 'TC/vnM  
sbkQ71T:  
XfE?C:v  
public void setNSplitter(int nCount) `!:q;i]}  
{ &c(WE RW?-  
nSplitter = nCount; 4(neKr5\#  
} HmfG$Z  
} 02`$OTKz  
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/* OH^N" L  
**Utility.java Ok7t@l$  
*/ aSuM2  
package NetFox; [XRCLi}  
?&LZB}1R  
b `2|I {  
public class Utility { cfox7FmW  
v%k9M{  
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public Utility() &R|/t:DN  
{ YSJy`  
)15Z#`x  
I)q,kP@yY  
} ZvYLL{>}w  
2)#K+O3c  
//线程睡眠 yKXff1^M  
public static void sleep(int nSecond) }>^Q'BW;65  
{ }R3=fbe,\  
try{ )&era` e[  
Thread.sleep(nSecond); ;U1UFqZ`  
} /vY_Y3k#  
catch(Exception e) a9n^WOJ6  
{ A*./,KT  
e.printStackTrace (); lPLz@Up~  
} *5zrZ]^  
} Ngr/QL]Q  
$M_x!f'{>  
//日志 #-3=o6DCK  
public static void log(String sMsg) SVjl~U-^  
{ d=,%=@  
System.err.println(sMsg); `X,yM-(  
} r1ws1 rr=  
2&+#Vsm`V  
=n^!VXaL]]  
public static void log(int sMsg) th6+
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{ DC1'Kyk  
System.err.println(sMsg); b
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} yNm:[bOER  
} '(f/~"9B  
:Rs^0F8)c  
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/* )CX4kPj  
**TestMethod.java \#68;)+=  
*/ O62b+%~F  
package NetFox; p8
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public class TestMethod { Y(\T- bI  
0!z@2[Pe66  
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public TestMethod() 2_Wg!bq  
{ ///xx/weblogic60b2_win.exe ;['[?wk  
try{ Ro2d,'   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9Pw0m=4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {JV@"t-X3"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "O8gJ0e  
fileFetch.start(); mDh1>>K'~  
} =8gHS[  
catch(Exception e){e.printStackTrace ();} C"lJl k9g^  
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2oJb)CB  
} 1<ro7A4hK  
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public static void main(String[] args) k%y9aO  
{ mAk{"65V  
new TestMethod(); ?Qb<-~~ j1  
} kt4d;4n  
} CE15pNss  
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