http断点续传简单实现（java)

/* [m t.2.  
**SiteFileFetch.java {|+Y;V`  
*/ E h%61/  
package NetFox; d"$8-_K  
import java.io.*; .1x04Np!  
import java.net.*; )s2] -n}W  
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public class SiteFileFetch extends Thread { c}x1-d8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KaGUpHw  
long[] nStartPos; //开始位置 $EMOz=)I#  
long[] nEndPos; //结束位置 2EY"[xK|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B*7kX&Uq  
long nFileLength; //文件长度 eE;tiX/  
boolean bFirst = true; //是否第一次取文件 #m+!<  
boolean bStop = false; //停止标志 q!c(~UVw  
File tmpFile; //文件下载的临时信息 8Of
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DataOutputStream output; //输出到文件的输出流 I0=_=aZO(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'nJF:+30ZH  
public SiteFileFetch(SiteInfoBean bean) throws IOException R+sT &d  
{ r;cDYg  
siteInfoBean = bean; MatXhP] Fi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \?:L>-&h8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GnV0~?  
if(tmpFile.exists ()) <J[le=  
{ ~m%[d. }e  
bFirst = false; :dmE/Tq  
read_nPos(); IS C.~q2  
} vNv?trw  
else *2X6;~  
{ ^s,3*cAU  
nStartPos = new long[bean.getNSplitter()]; vccWe7rh  
nEndPos = new long[bean.getNSplitter()]; wak26W>I3  
} 1I Yip\:lS  
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} y48]|%73  
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public void run() [f6uwp  
{ wNONh`b  
//获得文件长度 GqFx^d
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//分割文件 5
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//实例FileSplitterFetch ?z ,!iK`  
//启动FileSplitterFetch线程 ?7{U=1gb$  
//等待子线程返回 ];r! M0  
try{ PSrx!  
if(bFirst) ,|%K
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{ ,"qCz[aDN1  
nFileLength = getFileSize(); 3F9V,zWtTi  
if(nFileLength == -1) :XKYfc_y  
{ O5dS$[`j\p  
System.err.println("File Length is not known!"); Da^q9,|  
} `At.$3B  
else if(nFileLength == -2) lR(9;3  
{ <,.$U\W  
System.err.println("File is not access!"); l\U Q2i  
} g/?Vl2W  
else WR+j?Fcf  
{ c '|*{%<e2  
for(int i=0;i<nStartPos.length;i++) s"L&y <?)  
{ RK# 6JfC3X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w7)pBsI  
} cJKnB!iL5  
for(int i=0;i<nEndPos.length-1;i++) <J%qzt}  
{ QE]@xLz  
nEndPos = nStartPos[i+1]; = XZU9df  
} tldT(E6  
nEndPos[nEndPos.length-1] = nFileLength; fif;n[<  
} t]c<HDCK  
} }2 S.  
O7.V>7Y9H  
O[X*F2LC4  
//启动子线程 Zy0M\
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HOW<IZ^  
for(int i=0;i<nStartPos.length;i++) ;R$G.5h  
{ YSjc=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g&RpE41x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LpHGt]|D  
nStartPos,nEndPos,i); "$BkO[IS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UrniJB]  
fileSplitterFetch.start(); 8 Ku9;VEk  
} 'afW'w@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xvGYd,dlK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MmJMx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hV3]1E21"  
nEndPos = " + nFileLength); 3s\UU2yr  
// fileSplitterFetch[nPos.length-1].start(); vc#o(?g  
%<
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U$:^^Zt`B  
//等待子线程结束 F6{g{ B  
//int count = 0; EeaJ
UK]z9  
//是否结束while循环 +o+f\!  
boolean breakWhile = false; l&& i`  
&Vj@){  
sbvP1|P8%  
while(!bStop) ,~L*N*ML  
{ =i~ = |K!  
write_nPos(); 5{H)r  
Utility.sleep(500); d%EdvM|)  
breakWhile = true; \mF-L,yu  
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for(int i=0;i<nStartPos.length;i++) G>~/  
{ `n+uA~  
if(!fileSplitterFetch.bDownOver) 2d[tcn$;h]  
{ kn#?+Q  
breakWhile = false; 3P_.SF  
break; Ehy(;n)\  
} yf{\^^ i(  
} 8YSvBy  
if(breakWhile) ^;II@n i  
break; $`xpn#lz  
|E13W  
`=Mk6$%Cs  
//count++; df{?E):  
//if(count>4) O!PGZuF  
// siteStop(); Z%#e* O0  
} =K@LEZZ'/<  
(~@.9&cBD  
clDn=k<  
System.err.println("文件下载结束！"); |@d(2f8  
} ->#wDL!6  
catch(Exception e){e.printStackTrace ();} Tp;W  
} |A4B4/!  
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//获得文件长度 mq{Z Q'  
public long getFileSize() *Y1s4FXu2  
{ 3SM'vV0[  
int nFileLength = -1; YBY;$&9  
try{ v~RxtTu  
URL url = new URL(siteInfoBean.getSSiteURL()); X6sZwb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r E1ouz!D  
httpConnection.setRequestProperty("User-Agent","NetFox"); uWGp>;meO  
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int responseCode=httpConnection.getResponseCode();
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if(responseCode>=400) j %MY6"  
{ w2$ L;q  
processErrorCode(responseCode); 0r@LA|P  
return -2; //-2 represent access is error ,>g(%
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} Z$0mKw  
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String sHeader; ;8F6a:\v  
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for(int i=1;;i++) 9(&$Gwi  
{ ),<h6$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E?0RR'  
//Utility.log(in.readLine()); PHsM)V+  
sHeader=httpConnection.getHeaderFieldKey(i); o
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if(sHeader!=null) k \t6b1.M  
{ gi A(VUwI>  
if(sHeader.equals("Content-Length")) )sEAPIka  
{ /Wjf"dG}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m[5ed1+  
break; a 8jG')zg  
} bF@iO316H  
} yErvgf  
else zHj_q%A  
break; {XS2<!D  
} ku
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} 3~0Xe  
catch(IOException e){e.printStackTrace ();} *u<@_Oa  
catch(Exception e){e.printStackTrace ();} 7`X9s~B  
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Utility.log(nFileLength); 64!V8&Ay  
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return nFileLength; s&OwVQ<M  
} qo;F]v*pkK  
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}S
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//保存下载信息（文件指针位置） "2/VDB4!FG  
private void write_nPos() 7<ES&ls_  
{ gs|%3k|  
try{ 3?(||h{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hMs}r,*  
output.writeInt(nStartPos.length); 7" cgj#  
for(int i=0;i<nStartPos.length;i++) <tTn$<b  
{ BPKeG0F7  
// output.writeLong(nPos); K`1\3J)  
output.writeLong(fileSplitterFetch.nStartPos); ffyKAZ{]po  
output.writeLong(fileSplitterFetch.nEndPos); 4d3PF`,H`  
} p.1|bXY`  
output.close(); yHoj:f$$
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} |v{a5|<E  
catch(IOException e){e.printStackTrace ();} [H)p#x  
catch(Exception e){e.printStackTrace ();} nyPA
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} *$_<| g)9  
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//读取保存的下载信息（文件指针位置） sM~|}|p  
private void read_nPos() p2
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{ W#0pFofXw  
try{ te'<xfG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y6fU;  
int nCount = input.readInt(); Qo{^jDe,c*  
nStartPos = new long[nCount]; )r1Z}X(#d  
nEndPos = new long[nCount]; 88)0Xi|]KP  
for(int i=0;i<nStartPos.length;i++) :ZU  
{ fwxyZBr  
nStartPos = input.readLong(); /tP"r}l   
nEndPos = input.readLong(); ;][1_  
} l=EIbh  
input.close(); j|HOry1E&  
} -\>Bphu,y
 
catch(IOException e){e.printStackTrace ();} w},k~5U^s  
catch(Exception e){e.printStackTrace ();} 2J|Yc^b6  
} R^_/iy  
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private void processErrorCode(int nErrorCode) D 7H$!(F>  
{ t]"3vE>  
System.err.println("Error Code : " + nErrorCode); se$GE:hC1Q  
} U4zyhj  
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m[ txKj.=_  
//停止文件下载 &Cdk%@Tj]B  
public void siteStop() Y@^MU->+  
{ m]Z& .,bA  
bStop = true; tX Z5oG7  
for(int i=0;i<nStartPos.length;i++) &gcKv1a\  
fileSplitterFetch.splitterStop(); 01#a  
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} Cq/*/jBM  
} 9)T;.O  
//负责部分文件的抓取 nvsuF)%9hZ  
**FileSplitterFetch.java `2d,=.X  
*/ i v&:X3iB  
package NetFox; n>Q/XQXB  
#$X_,P|D  
3@s|tm1  
import java.io.*; Ry[V
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import java.net.*; i4v7x;m_p  
)5)S8~Oc  
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public class FileSplitterFetch extends Thread { (PE"_80Z  
+;pdG[N  
lJu2}XRiU  
String sURL; //File URL &D>e>]E|P  
long nStartPos; //File Snippet Start Position {Qg"1+hhM  
long nEndPos; //File Snippet End Position qnv9?Xh  
int nThreadID; //Thread's ID ,H1j&]E!  
boolean bDownOver = false; //Downing is over KE&Y~y8O\  
boolean bStop = false; //Stop identical ]f-< s,@  
FileAccessI fileAccessI = null; //File Access interface ^'*9,.ltd  
9]Uvy|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `8KWZi4 ]  
{ e ,k,L  
this.sURL = sURL; ,cYU
 
this.nStartPos = nStart; {SbA(a?B  
this.nEndPos = nEnd; /Rb`^n#  
nThreadID = id; "<t/*$
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 sr sDnf  
} / \!hW-+]W  
Wb68")$  
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public void run() ~:D
}L   
{ |/Am\tk#13  
while(nStartPos < nEndPos && !bStop) Se%FqI  
{ Nf%jLK~  
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88$G14aXEk  
try{ 8h78Zb&[  
URL url = new URL(sURL); H"tS33  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <}pqj3  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uz>5!_  
String sProperty = "bytes="+nStartPos+"-"; ]tanvJG}'  
httpConnection.setRequestProperty("RANGE",sProperty); h3h2 KqM'  
Utility.log(sProperty); UsNr$MO {  
E#URTt:&>  
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InputStream input = httpConnection.getInputStream(); 5-0
  
//logResponseHead(httpConnection); A5Qzj]{ba  
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byte[] b = new byte[1024]; <fCgU&  
int nRead; #9,!IW]l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {l-,Jbfi`  
{ P>z k  
nStartPos += fileAccessI.write(b,0,nRead); \_#0Z+pX  
//if(nThreadID == 1) KM*sLC#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aBj~370g  
} A=o p R  
f\!*%xS;  
7v}4 Pl,$4  
Utility.log("Thread " + nThreadID + " is over!"); pv~XZ(J.1  
bDownOver = true; ?g&6l0n`  
//nPos = fileAccessI.write (b,0,nRead); IvTtQq  
} L"rL
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catch(Exception e){e.printStackTrace ();} 9 %4Pt=v~d  
} L%ND?'@  
} s<cg&`u,<M  
@tdX=\[~  
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//打印回应的头信息 iOm~
 
public void logResponseHead(HttpURLConnection con) g+hz>^Wg  
{ c@1C|  
for(int i=1;;i++) w1F7gd  
{ `<zaxO  
String header=con.getHeaderFieldKey(i); _-H uO/  
if(header!=null) 46o3F"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (pm]U7  
Utility.log(header+" : "+con.getHeaderField(header)); v)N8vFdd  
else U5jY/e_  
break; 7=N=J<]pl  
} HNxJ`x~Z~  
} WM}:%T-  
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public void splitterStop() G'q7@d{'  
{ "Nj(0&  
bStop = true; W%hdS<b  
} J)Dw`=O0n  
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fz31di9$  
} P.$U6cq  
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/* VV)PSodb  
**FileAccess.java 6*cm  
*//文件访问(定位，写) *Af]?-|^{#  
package NetFox; SE)_
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import java.io.*; B++.tQ=X.  
+2O('}t  
e]!Vxn3  
public class FileAccessI implements Serializable{ "B*a| 'n!  
kV!0cLH!hH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s+(%N8B  
RandomAccessFile oSavedFile; M(HU^?B{'  
long nPos; /p~"?9b[ i  
jy(,^B,]  
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public FileAccessI() throws IOException J0a]Wz%  
{ 9"52b9U  
this("",0); &{9'ylv-B)  
} JiEcPii  
X5U_|XK6Y  
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public FileAccessI(String sName,long nPos) throws IOException vD D !.i  
{ m(q6Xe:Vc  
oSavedFile = new RandomAccessFile(sName,"rw"); v:B_%-GfOA  
this.nPos = nPos; >"jV8%!sM  
oSavedFile.seek(nPos); {S%)GvrT  
} ;@Ep?S@  
kFgN^v^t  
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public synchronized int write(byte[] b,int nStart,int nLen) zwR@^ 5^6  
{ Iwi>yx8  
int n = -1; "Ol;0>$  
try{ N#@xo)-H  
oSavedFile.write(b,nStart,nLen); }oYR.UH  
n = nLen; VH4P|w[YF  
} u><ax  
catch(IOException e) 'G>Ejh@t  
{ 7loCb4Hv
 
e.printStackTrace (); Ictc '#y  
} )wP0U{7?v  
8R`@edj>  
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return n; 5 usfyY]z  
} 4U<'3~RN  
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} +'>N]|Z  
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/* EhEn|%S
 
**SiteInfoBean.java |(}uagfrd  
*/ mz1Xk ]nE  
package NetFox; $}TqBBe  
mvVVPf9  
|o~FKy1'z\  
public class SiteInfoBean { [4 g5{eX  
Il2DZ5- )  
nuw90=qj!]  
private String sSiteURL; //Site's URL BT 98WR"\  
private String sFilePath; //Saved File's Path 3 C=nC  
private String sFileName; //Saved File's Name Z{chAg\
 
private int nSplitter; //Count of Splited Downloading File Z@ h<xo*r  
|?s%8c'w=  
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public SiteInfoBean() &w2
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{//nSplitter的缺省值为5 gwThhwR  
//default value of nSplitter is 5 JQ+4 SomK  
this("","","",5); X^_,`H@  
} u~LisZ&tP  
Br]VCp  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :eQ@I+  
{ $msT
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sSiteURL= sURL; LN?T$H  
sFilePath = sPath; $Y$!nPO  
sFileName = sName; |1g2\5Re  
this.nSplitter = nSpiltter; J2aA"BhdC"  
)K@ 20Q+0K  
X-Xf6&Uz  
} s=q\BmG  
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public String getSSiteURL() v&H&+:<  
{ TQ=\l*R(A  
return sSiteURL; s<:"rw`  
} DbPw)aCj  
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public void setSSiteURL(String value) SjlkKulMF  
{ t~5>PS  
sSiteURL = value; bRNE:))r_  
} >%#J8  
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public String getSFilePath() lG\lu'<C  
{ WNm,r>6m  
return sFilePath; O(&EnNm[2  
} ]d$)G4X1  
F{l,Tl"Jw  
%3xH<$Gq5  
public void setSFilePath(String value) ~JC``&6E=}  
{ _ esFx  
sFilePath = value; ,Oxdqxu7  
} D3XQ>T[*q  
"ajZ&{Z  
.WyI.Y1  
public String getSFileName() y;<jE.7>  
{ Z]9 )1&  
return sFileName; '?3Hy|}  
} O "{o (  
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public void setSFileName(String value) } k5pfz  
{ [W^6=7EO  
sFileName = value; O~qB  
} F!fxA#  
_BR>- :Jr  
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public int getNSplitter()
.Z/"L@  
{ rTmcP23]  
return nSplitter; )}paQmy#  
} c:=Z<0S;  
^GRd;v=-@  
:$P <e~z'  
public void setNSplitter(int nCount) YjHGdacs  
{ c!kbHZ<Z  
nSplitter = nCount; It]CoAo+  
} ;K:.*sAa  
} H2k>E}`  
{?5EOp~  
W:9L!+m^  
/* k)S7SbQ  
**Utility.java 2H]&3kM3X  
*/ .bpxSU%X  
package NetFox; >TL0hBaaR  
3!Bekn]  
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public class Utility { ?+5K2Zk  
8(g:i#~  
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public Utility() *a$z!Ma3h  
{ u_:" u  
p=Vm{i7  
/D~z}\k  
} RQe#X6'h  
2Db[dk( ]  
//线程睡眠 N'[^n,\(:  
public static void sleep(int nSecond) 4|Z3;;%+  
{ #]:nQ(  
try{ fmloh1{4  
Thread.sleep(nSecond); ?rr%uXQjH  
} zeR!Y yt!  
catch(Exception e) a2p<HW;)m  
{ ((t8  
e.printStackTrace (); &4BN9`|:  
} 8[zP2L!-  
} ]2Lwd@  
u^:!!Suo  
//日志 D+"5R5J",  
public static void log(String sMsg) 4'_uN$${$  
{ \mv7"TM  
System.err.println(sMsg); A u(Ngq  
} gbKms;:  
+gT?{;3[i  
<4(rY9  
public static void log(int sMsg) tR2IjvmsX  
{ w"A'uFXLc  
System.err.println(sMsg); )7J@A%u  
} _=,[5"  
} 3:);vh!  
m: w/[|_  
Oja)J-QXb  
/* oIbd+6>f  
**TestMethod.java Y_f6y9?ZE  
*/ z!t&zkAK  
package NetFox; PsLuyGR.<  
|4wVWJ7   
.cle^P  
public class TestMethod { ]36R_Dp  
~f){`ZJc  
'<8ew
U  
public TestMethod() :2  
{ ///xx/weblogic60b2_win.exe 2<Ub[R  
try{ Vk>aU3\c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .qF@ }dO
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 30[?XVI&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); W^al`lg+y  
fileFetch.start(); xae}8E  
} tQ] R@i  
catch(Exception e){e.printStackTrace ();} GQ)hZt0  
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hwkol W  
} m.S@ e8kS  
RQ9T<t42  
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public static void main(String[] args) &~^"yo#b  
{ )SUT+x(DU  
new TestMethod(); b^^Cj(  
} [4(TG<I  
} jcFh2  
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