http断点续传简单实现（java)

/* $VRVMY [q  
**SiteFileFetch.java yoc;`hO-  
*/ ZgD%*bH*B  
package NetFox; g{d(4=FM  
import java.io.*; 2MQ XtK  
import java.net.*; bxrT[]  
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public class SiteFileFetch extends Thread { <g4
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1O{(9nNj  
long[] nStartPos; //开始位置 8uZM%7kI6+  
long[] nEndPos; //结束位置 fKYRDGn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _b)=ERBbCo  
long nFileLength; //文件长度 *`g'*R  
boolean bFirst = true; //是否第一次取文件 !um~P  
boolean bStop = false; //停止标志 b2<((H  
File tmpFile; //文件下载的临时信息 P56B~M_  
DataOutputStream output; //输出到文件的输出流 *@1(!A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） k/;%{@G)  
public SiteFileFetch(SiteInfoBean bean) throws IOException K\3N_ztu  
{ PDi]zp9>H  
siteInfoBean = bean; xB<^ar  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q<Sb>M/
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); NZW)$c'  
if(tmpFile.exists ()) .%x%b6EI  
{ :Ou[LF.O  
bFirst = false; b:6NVHb%  
read_nPos(); f2f2&|7  
} (.Th?p%>7  
else vi1 D<  
{ )oU%++cdo  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()];  'K7m!y  
} n
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} XTro;R=#  
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public void run() hzcSKRm  
{ L%Mj{fJ>Wm  
//获得文件长度 :I!}Z
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//分割文件 CAT{)*xc  
//实例FileSplitterFetch o0}kRL  
//启动FileSplitterFetch线程 6a!b20IZh  
//等待子线程返回 V<&^zIJUR  
try{ ARd*c?Om  
if(bFirst) nd#owjB  
{ o6Jhl8  
nFileLength = getFileSize(); z55g'+Kab  
if(nFileLength == -1) AdgZau[Y6  
{ iz-B)^8.  
System.err.println("File Length is not known!"); pt_]&3\e  
} B{hV|2  
else if(nFileLength == -2) 4o69t  
{ ]]^r)&pox  
System.err.println("File is not access!"); R}E$SmFg  
} &y&pjo6v1  
else h2P&<ggqX  
{ o5;|14O  
for(int i=0;i<nStartPos.length;i++) O/b1^ Y   
{ ?[#4WH-G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m>{I>:sq  
} 1/tyne=m  
for(int i=0;i<nEndPos.length-1;i++) '(fzznRH  
{ "%
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nEndPos = nStartPos[i+1]; m88(f2Ch  
} pJo#7rxd6  
nEndPos[nEndPos.length-1] = nFileLength; [O@U@bD9  
} me YSW  
} U_C[9Z'P  
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//启动子线程 044Q>Qz,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :2*0Jh3_  
for(int i=0;i<nStartPos.length;i++) @>q4hYF  
{ -_^#7]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y;1s=B9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ql I1<Jx  
nStartPos,nEndPos,i); AvZOR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %zYTTPLZ  
fileSplitterFetch.start(); xFA+ZjBC  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R q .2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,X)/ T!ff  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E^C [G)7n  
nEndPos = " + nFileLength); `1i\8s&O6@  
// fileSplitterFetch[nPos.length-1].start(); ?`3G5at)9f  
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//等待子线程结束 wJg&OQc9  
//int count = 0; C {G647  
//是否结束while循环 ? ]H'egG6  
boolean breakWhile = false; l{8t;!2t  
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7?]wAH89  
while(!bStop) 1B`JvNtd  
{ ^%t{:\  
write_nPos(); p?' F$Wz  
Utility.sleep(500); Exz(t'  
breakWhile = true; "P!zu(h4  
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for(int i=0;i<nStartPos.length;i++) /xb37,   
{ gJg%3K~,  
if(!fileSplitterFetch.bDownOver) $xK(bc'{  
{ ,GMuq_H  
breakWhile = false; 49Hgq/uO  
break; ~
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} yHnN7&  
} 0Ci:w|J  
if(breakWhile) (G 9Ku 8Y  
break; yPks,7U  
mMtva}=*  
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//count++; $%zM Z  
//if(count>4) BWLeitS/  
// siteStop(); 7!A3PDAe  
} Q5c13g2
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System.err.println("文件下载结束！"); _Kv;hR>  
} IFkU8EK&B  
catch(Exception e){e.printStackTrace ();} _/5xtupxE  
} keS%w]87  
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//获得文件长度 r?R!/`f  
public long getFileSize() n:[LsbTk  
{ rp!>rM] s  
int nFileLength = -1; V&R_A~<T  
try{ fvM|Jb  
URL url = new URL(siteInfoBean.getSSiteURL()); vqRW^>~-B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e$4l[&kH_  
httpConnection.setRequestProperty("User-Agent","NetFox"); g.x]x#BC  
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int responseCode=httpConnection.getResponseCode(); D1~3 3;  
if(responseCode>=400) 6@
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{ e2Df@8>  
processErrorCode(responseCode); J-Wphc!m  
return -2; //-2 represent access is error ;op
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} bEl)/z*gy/  
?&"!,  
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String sHeader; }zqYn`ffD  
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[ FNA:  
for(int i=1;;i++) 6Ej@;]^^-  
{ y0cB@pWp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S<DS|qOo  
//Utility.log(in.readLine()); n##d!d|g  
sHeader=httpConnection.getHeaderFieldKey(i); `+EjmY  
if(sHeader!=null) Pt8 U0)i)  
{ S`&YY89{&  
if(sHeader.equals("Content-Length")) H8?Kgaj~vf  
{ 5mF"nY&lI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jl~?I*Gr  
break; /]"2;e-s+  
} @Xq3>KJ_)H  
} yf7$m_$C'  
else K;#9: Z^+  
break; mdPEF)-  
} jwZBWt )5  
} psZ #^@>mJ  
catch(IOException e){e.printStackTrace ();} 5b-: e? |  
catch(Exception e){e.printStackTrace ();} )]3(ue  
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Utility.log(nFileLength); cG~-OHU  
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return nFileLength; 0N19R5NN8  
} Wf>scl`s  
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#Jqa_$\.  
//保存下载信息（文件指针位置） J)leRR&  
private void write_nPos() Zjx:1c= b  
{ QSq0{  
try{ #[C=LGi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W dNOE;R  
output.writeInt(nStartPos.length); l@OY8z-_  
for(int i=0;i<nStartPos.length;i++) p\ }Ep  
{ C[xY 0<^B  
// output.writeLong(nPos); `oq][|  
output.writeLong(fileSplitterFetch.nStartPos); vRQ7=N{3  
output.writeLong(fileSplitterFetch.nEndPos); ]F4.m  
} "$Mz>]3&q  
output.close(); %2jRJ  
} OmR)W'  
catch(IOException e){e.printStackTrace ();} yxx'g+D*  
catch(Exception e){e.printStackTrace ();} \6)]!$F6:  
} e 1$<,.>  
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//读取保存的下载信息（文件指针位置） =W_Pph  
private void read_nPos() (Iz$_(  
{ Oe["4C  
try{ +-*Ww5Zti  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Jb (CH4|7  
int nCount = input.readInt(); /)<x<7FKW  
nStartPos = new long[nCount]; ym=7EY?o  
nEndPos = new long[nCount]; Y%1 94fY$
 
for(int i=0;i<nStartPos.length;i++) -0>gq$/N=^  
{ +338z<'Z!  
nStartPos = input.readLong(); 4{rqGC/  
nEndPos = input.readLong(); 'fIoN%  
} # zbAA<f  
input.close(); #@3&1}J/  
} n,_q6/!  
catch(IOException e){e.printStackTrace ();} <Cbi5DtR  
catch(Exception e){e.printStackTrace ();} NrK.DY4  
} Y*Ra!]62  
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private void processErrorCode(int nErrorCode) _*m<Z;Et  
{ l3O!{&~K  
System.err.println("Error Code : " + nErrorCode); <1%(%KdN[  
} 
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w$##GM=Tq  
//停止文件下载 A 6IrA/b  
public void siteStop() bQlvb  
{ LN0pC}F  
bStop = true; /L yoTBG  
for(int i=0;i<nStartPos.length;i++) BtA_1RO  
fileSplitterFetch.splitterStop(); Rl/5eE8  
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} 31^
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} ouE/\4'NB  
//负责部分文件的抓取 wr-/R"fX  
**FileSplitterFetch.java uSgR|b;R]  
*/ YstR T1  
package NetFox; >_J9D?3S  
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import java.io.*; .US=fWyrb  
import java.net.*; ~~\C.6c#  
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public class FileSplitterFetch extends Thread { XU y[l  
0H/)wy2ym  
{ )-8P  
String sURL; //File URL _1,hO?TK  
long nStartPos; //File Snippet Start Position &.l^>#  
long nEndPos; //File Snippet End Position [} zzG@g,J  
int nThreadID; //Thread's ID lsaA    
boolean bDownOver = false; //Downing is over D){my_ /  
boolean bStop = false; //Stop identical I
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FileAccessI fileAccessI = null; //File Access interface 2{Y~jYt{h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `y|_hb  
{ uCr :+"C  
this.sURL = sURL; GoLK 95"]  
this.nStartPos = nStart; ^6On^k[|fw  
this.nEndPos = nEnd; O joa3  
nThreadID = id; ,gpZz$Ef(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7 x'2  
} Kh$Q9$  
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[{$%9lm  
public void run() Nq%ir8hE  
{ C-@[=
 
while(nStartPos < nEndPos && !bStop) bksv2@ar  
{ Fw S>V2R  
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try{ _%[po%]  
URL url = new URL(sURL); YF)]B|I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mqj-/DN6*  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~Pj q
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String sProperty = "bytes="+nStartPos+"-"; (3"N~\9m  
httpConnection.setRequestProperty("RANGE",sProperty); %.m+6 zaF  
Utility.log(sProperty); ZTibF'
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InputStream input = httpConnection.getInputStream(); aeISb83Y|  
//logResponseHead(httpConnection); }T0O~c{$i  
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byte[] b = new byte[1024]; 9Ta0Li  
int nRead; dU#-;/}o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CLTkyS)C  
{ ;=7K*npT  
nStartPos += fileAccessI.write(b,0,nRead); V)5K/U{  
//if(nThreadID == 1) rlaeqG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W6Mq:?+D  
} '4nJ*Xa  
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Utility.log("Thread " + nThreadID + " is over!"); m8=n`XI  
bDownOver = true; ?=ffv]v|  
//nPos = fileAccessI.write (b,0,nRead); J#48c'  
} >.6|\{*sG  
catch(Exception e){e.printStackTrace ();} f~F{@),acZ  
} _1NK9dp:  
} 'zM=[#!B  
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//打印回应的头信息 HhL;64OYa  
public void logResponseHead(HttpURLConnection con) sO` oapy  
{ n>?D-)g  
for(int i=1;;i++) +SR{FF  
{ S3:
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String header=con.getHeaderFieldKey(i); Kv(R|d6Lp  
if(header!=null) }DXG;L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =gs-#\%  
Utility.log(header+" : "+con.getHeaderField(header)); (-g*U#  
else NJ)Dw`|%|)  
break; ~_-]> SI  
} jM&di  
} ;F#(:-:  
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public void splitterStop() WFiX=@SS  
{ s(nT7x+W  
bStop = true; b,^Gj]7  
} 'Y/0:)
 
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} r|=1{Nx  
fO$){(]^  
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/* v,S5C
  
**FileAccess.java 4WJY+)  
*//文件访问(定位，写) p_h/hTi  
package NetFox; QYMfxpiC  
import java.io.*; |)+ SG>-  
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public class FileAccessI implements Serializable{ ?0_<u4  
VD~5]TQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F
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RandomAccessFile oSavedFile; gLB(A\yG  
long nPos; %W"u4 NT7  
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public FileAccessI() throws IOException 4kjfYf@A  
{ %+H_V1F  
this("",0); 3l~+VBR_  
} lcie6'<  
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public FileAccessI(String sName,long nPos) throws IOException 4LKpEl.=  
{ :Ln)j%&  
oSavedFile = new RandomAccessFile(sName,"rw"); |gA@WV-%  
this.nPos = nPos; ' @RF  
oSavedFile.seek(nPos); >`\.i,X.D  
} zak\%yY`  
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z_!IA ] v  
public synchronized int write(byte[] b,int nStart,int nLen) ? `p/jA  
{ o{G*7V@H  
int n = -1; A$=ny6  
try{ :$$~$P  
oSavedFile.write(b,nStart,nLen); nbF<K?  
n = nLen; }6@E3z]AMO  
} orFwy!  
catch(IOException e) &KjMw:l  
{ #NW+t|E  
e.printStackTrace (); Jt=->  
} `qc"JB  
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,*J@ic7"  
return n; s/tLY/U/  
} XgC^-A w  
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} |%C2 cx  
XM`GK>*aC(  
?$|tT\SFV  
/* 0f6o0@  
**SiteInfoBean.java `NNP<z+\  
*/ 8Yh'/,o=L#  
package NetFox; [)Nt;|U  
J<0{3pZY  
9wYm(7M6  
public class SiteInfoBean { ~_fc=^o  
wa8jr5/k"  
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private String sSiteURL; //Site's URL N1Vj;-  
private String sFilePath; //Saved File's Path A0<g8pv  
private String sFileName; //Saved File's Name $@L;j  
private int nSplitter; //Count of Splited Downloading File k|/VNV( =0  
/oT~CB..  
ZAr6RRv ^  
public SiteInfoBean() \>6*U r  
{//nSplitter的缺省值为5 ,)1C"'  
//default value of nSplitter is 5 SE+hB  
this("","","",5); {Dpsr` &  
} V vrsf6l]  
.dU91> ~Ov  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NV* 2  
{ kG/1  
sSiteURL= sURL; @P7'MiP]K  
sFilePath = sPath; (%X *b.n=  
sFileName = sName; 1kvX#h&V  
this.nSplitter = nSpiltter; FOQ-KP\=,  
5-X$"Z|@  
gy}3ZA*F  
} cy8>M))c  
8J3#(aBm  
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public String getSSiteURL() V *@q< rQ  
{ ^*}D*=>\  
return sSiteURL; 7Mh'x:p  
} 28"1ONs3  
VZi1b0k1.  
v WXo#  
public void setSSiteURL(String value) th{f|fm62  
{ G3_7e A#;  
sSiteURL = value; =`3r'c  
} l ms^|?  
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public String getSFilePath() )Z:-qH  
{ T \/^4N`  
return sFilePath; ArtY;.cg%  
} 0eA<nK  
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public void setSFilePath(String value) ~EBaVl ({  
{ U2A-ub>7  
sFilePath = value; T
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} #`_W?-%^  
]V/5<O1  
q]="ek&_  
public String getSFileName() E:9RskI  
{ &}u_e`A  
return sFileName; w: BJ4bi=  
} ._0$#J S[  
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X?haHM#]  
public void setSFileName(String value) &>c=/]Lop  
{ 7**zb"#y  
sFileName = value; j0L%jz
 
} (')t>B1Z  
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12 )  
public int getNSplitter() rPB Ju0D"  
{ t%mi#Gh(  
return nSplitter; MEI&]qI  
} wf  ]Wm  
s>DFAu!  
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public void setNSplitter(int nCount) OkRb3}  
{ \ ERBb.  
nSplitter = nCount; <\~@l^lU  
} PlCw,=K8f  
} 2_Lu0Yrg  
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eV_",W  
/* LiEEQ  
**Utility.java <RxxGD  
*/ Nn_b  
package NetFox; t]sk[  
}D1?Z7p  
!v3d:n\W8  
public class Utility { |$tF{\  
\/dOv

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public Utility() %5L~&W}^"  
{ l%V+]skS  
."Pn[$'.  
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} -wUT@a  
=n.&N   
//线程睡眠 {U9{*e$=  
public static void sleep(int nSecond) *=md!^x`  
{ 7IUJHc?  
try{ [?6+ r  
Thread.sleep(nSecond); G9S3r3  
} *[>{9V  
catch(Exception e) ~&,S xQT  
{ m!INbIh  
e.printStackTrace (); h9d*N9!;M  
} K z^.v`  
} "'+/ax[{  
A/zAB3  
//日志 M\ wCZG  
public static void log(String sMsg) rhF2U  
{ Ozqh Jb  
System.err.println(sMsg); D{7sfkcJ  
} N/C$8D34  
#x;d+Q@  
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public static void log(int sMsg) )3F}IgD  
{ =m|<~t  
System.err.println(sMsg); 2n"-~'3\  
} dM"5obEb  
} YxnZ0MY  
DW,Z})9  
s&%r?  
/* k-4
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**TestMethod.java Yi-,Pb?   
*/ {DVMs|
5;^  
package NetFox; 5/hgWG6.t  
ga'G)d3oS  
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public class TestMethod { g6gwNC:aF  
KfK5e{yT  
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public TestMethod() /`qQWB5b  
{ ///xx/weblogic60b2_win.exe ;Gu(Yoa}y  
try{ 1q ZnyJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8&hxU@T~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OZKZv,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zl, Vj%d  
fileFetch.start(); vqF=kB"P  
} F.Bij8\  
catch(Exception e){e.printStackTrace ();} }L`Z<h*H  
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} ^c}kVQ\g3  
6 {`J I  
[$]-W$j+  
public static void main(String[] args) D7IhNWrgj  
{ B_@p@6z  
new TestMethod(); \^cXmyQ<%  
} !(S.7#-r  
} oh:.iL}j  
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