http断点续传简单实现（java)

/* {vox x&UX  
**SiteFileFetch.java ='Fh^]*5  
*/ \kEC|O)8  
package NetFox; Y^-D'2P]P  
import java.io.*; ,ePl>m:Z  
import java.net.*; !~fy".|x  
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public class SiteFileFetch extends Thread { 82KWe=  
/4{IxQk  
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SiteInfoBean siteInfoBean = null; //文件信息Bean SmCtwcB1  
long[] nStartPos; //开始位置 >^J
  
long[] nEndPos; //结束位置 |H&&80I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,&iZ*6=X?0  
long nFileLength; //文件长度 ?F/)<r  
boolean bFirst = true; //是否第一次取文件 DT[WO_=  
boolean bStop = false; //停止标志 o|Kd\<rY  
File tmpFile; //文件下载的临时信息 ]:}x 4O#  
DataOutputStream output; //输出到文件的输出流 6oy[0hj  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Hh`HMa'q  
public SiteFileFetch(SiteInfoBean bean) throws IOException oz&RNB.K  
{ 4b 1a?  
siteInfoBean = bean; X3R:^ff\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p@[n(?duC.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h)h%y)1  
if(tmpFile.exists ()) 4MPR
  
{ EFzPt?l  
bFirst = false; RW|Xh8.O  
read_nPos(); 9"cyZO  
} $ 9 k5a  
else 3"LT''  
{ +@qIDUiF3  
nStartPos = new long[bean.getNSplitter()]; ~*hCTqHvN  
nEndPos = new long[bean.getNSplitter()]; r:--DKt  
} J!d=aGY0-  
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} YYF.0G}  
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public void run() lQ!(lPh  
{ 9{CajtN  
//获得文件长度 UY^TTRrH  
//分割文件 \:9<d@?  
//实例FileSplitterFetch $%.,=~W7  
//启动FileSplitterFetch线程 `*y%[J,I#  
//等待子线程返回 pMV?vH  
try{ *X8Pa;x  
if(bFirst) c]A @'{7  
{ 349BQ5ND  
nFileLength = getFileSize(); NfND@m{/  
if(nFileLength == -1) ', P_a,\  
{ }#phNn6  
System.err.println("File Length is not known!"); dZuPR  
} "1%\Fil  
else if(nFileLength == -2) }%`f%/  
{ .$a|&P=S  
System.err.println("File is not access!"); iM M s3  
} d"OYq
 
else F0ylJ /E  
{ hq?F81  
for(int i=0;i<nStartPos.length;i++) =kjD ]+l  
{ cv-;fd>'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fU|4^p)  
} +zZ]Txb(  
for(int i=0;i<nEndPos.length-1;i++) 5#mHWBGd7  
{ )WsR 8tk  
nEndPos = nStartPos[i+1]; -%TwtO<$']  
} e, }{$HStZ  
nEndPos[nEndPos.length-1] = nFileLength; d#|%h] 6  
} lw_@(E]E  
} uoTc c|Kc  
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lm|s
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//启动子线程 wowWq\euY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7ea%mg\  
for(int i=0;i<nStartPos.length;i++) &(h@]F!  
{ &"DD&87N%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >%A~ :  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "rHPcp"m  
nStartPos,nEndPos,i); `a5,5}7v%`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s:oj
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fileSplitterFetch.start(); /$^SiE+N  
} Z_s]2y1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >=/DCQ$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .p%V]Ka  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O)c3Lm-w  
nEndPos = " + nFileLength); UaBN
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// fileSplitterFetch[nPos.length-1].start();
L
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n^` `)"  
:PNhX2F  
//等待子线程结束 qRXHaQi@9  
//int count = 0; .F3~eas  
//是否结束while循环 VVqpzDoXG  
boolean breakWhile = false; `KUL4) g~  
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while(!bStop) zS'{F>w  
{ 7pM&))
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write_nPos(); <7o@7r'0  
Utility.sleep(500); 83F]d+n  
breakWhile = true; u.2^t:A  
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for(int i=0;i<nStartPos.length;i++) |-xKH.'n  
{ $]MOAj"LH  
if(!fileSplitterFetch.bDownOver) U04)XfO;]  
{ wsgT`M'J[  
breakWhile = false; @B9#Hrc  
break; S2?)Sb`  
} YGhHIziI  
} x$KQ*P~q  
if(breakWhile) c3*9{Il^  
break; P_(<?0l  
{6iHUK  
wrVR[
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//count++; %>t4ib_8  
//if(count>4) +1Pu29B0  
// siteStop(); zLg_0r*h1  
} pIY3ft\  
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0G3T.4I  
System.err.println("文件下载结束！"); k[\JT[M
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} Vk%W4P"l  
catch(Exception e){e.printStackTrace ();} j#${L6  
} j6Au<P  
t![972.&  
n6{nx[%7N7  
//获得文件长度 BR
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public long getFileSize() Tx(=4ALY  
{ Ox6^=D"  
int nFileLength = -1; TSj)XU {W  
try{ \3whM6tK  
URL url = new URL(siteInfoBean.getSSiteURL()); yppXecFJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4|NcWpaV7  
httpConnection.setRequestProperty("User-Agent","NetFox"); N|w;wF!3  
*-gmWATC6  
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int responseCode=httpConnection.getResponseCode(); e r"gPW  
if(responseCode>=400) ;V^I>-fnm  
{ V,eH E5C  
processErrorCode(responseCode); sNJ?Z"5k1h  
return -2; //-2 represent access is error Nrc-@ ]  
} >Vb V<ak  
D1EHT
}  
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String sHeader; s"l ^v5  
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for(int i=1;;i++) q[+V6n`Z5  
{ W |+&K0M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \p\rPfY{>  
//Utility.log(in.readLine()); (ewcj\l4*  
sHeader=httpConnection.getHeaderFieldKey(i); IXsOTBM  
if(sHeader!=null) 8\[q
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{ C12y_E8Un  
if(sHeader.equals("Content-Length")) N~B'gJJDx  
{ `;&=m, W'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =%wBC;  
break; #M92=IH  
} [bd?$qi  
} 2hTH  
else I#|ib  
break; 0
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} j{P3o<l&`  
} yJw4!A 1!  
catch(IOException e){e.printStackTrace ();} op
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catch(Exception e){e.printStackTrace ();} Do;rY\sY  
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Utility.log(nFileLength); ;T WYO  
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return nFileLength; ;sd] IZ$#  
} jce2lXMm  
%$F\o1S  
I)4NCjcCw  
//保存下载信息（文件指针位置） \fL:Ie  
private void write_nPos() VB{G%!}  
{ 2|LkCu)~,"  
try{ y#5;wb<1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^Xsl
j  
output.writeInt(nStartPos.length); RQ[6svfP  
for(int i=0;i<nStartPos.length;i++) Q3x.qz  
{ [RHji47  
// output.writeLong(nPos); mOx>p"n  
output.writeLong(fileSplitterFetch.nStartPos); ">S.~'ds  
output.writeLong(fileSplitterFetch.nEndPos); ~ph>?xuw  
} 6Q9S~YYq  
output.close(); ,T7(!)dR  
} 8 9f{8B]z  
catch(IOException e){e.printStackTrace ();} mKBPIQ+ZS  
catch(Exception e){e.printStackTrace ();} U+g<lgH1J  
} P3V}cGZ  
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//读取保存的下载信息（文件指针位置） :@+@vM;gh  
private void read_nPos() *5;#+%A  
{ j es[a  
try{ cGe-|>:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h:'wtn@l(  
int nCount = input.readInt(); yy|F6Pq3`  
nStartPos = new long[nCount]; Sc&p*G  
nEndPos = new long[nCount]; %ck/ Z  
for(int i=0;i<nStartPos.length;i++) Q GDfX_  
{ T13Jno  
nStartPos = input.readLong(); .R{P%r  
nEndPos = input.readLong(); k%lz%r  
} j0[9Cj^%c  
input.close(); C@s;0-qL  
} =k22f`8ew  
catch(IOException e){e.printStackTrace ();} > v ]-B"Y  
catch(Exception e){e.printStackTrace ();} STgYXA(  
} /h73'"SpDy  
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{ Sn J  
private void processErrorCode(int nErrorCode) d/`Q,Vl  
{ ?BnjtefIe  
System.err.println("Error Code : " + nErrorCode); 4 g^oy^~  
} X
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' fP`ET5  
0CRk&_ht  
//停止文件下载 Kzgnhgc  
public void siteStop() ?AJE*=b  
{ >pn5nn1a  
bStop = true; VtD
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for(int i=0;i<nStartPos.length;i++) 2s:$4]K D  
fileSplitterFetch.splitterStop(); >0qe*4n|M  
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9~$'?  
} 96 !e:TU  
} RP4P"m(
 
//负责部分文件的抓取 VCUEz
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**FileSplitterFetch.java u|]`
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*/ VVyms7 VN  
package NetFox; \@HsMV2+zN  
'VTLp.~G~  
IF$*6 ,v.z  
import java.io.*; =HkB>w)h  
import java.net.*; gnN"pa!&~  
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public class FileSplitterFetch extends Thread { L@HWm;aN  
n:wZL&ZV0  
s
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String sURL; //File URL J 4OgV?  
long nStartPos; //File Snippet Start Position y6S:[Z{~A  
long nEndPos; //File Snippet End Position VaRP+J}UA.  
int nThreadID; //Thread's ID N/&t)7  
boolean bDownOver = false; //Downing is over q k+(Ccl  
boolean bStop = false; //Stop identical B`SHr"k!V[  
FileAccessI fileAccessI = null; //File Access interface 6:vdo~  
Xm!;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'u{DFMB-A  
{ x<%V&<z1g  
this.sURL = sURL; IDpW5Dc  
this.nStartPos = nStart; mlD 1 o  
this.nEndPos = nEnd; v}AVIdR  
nThreadID = id; <^(g<B`>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >AT T<U=  
} yl[6b1  
`<:D.9vO "  
A(Ss:7({  
public void run() ;K9rE3  
{ oH|<(8efD  
while(nStartPos < nEndPos && !bStop) ry%Fs&V*>  
{ 1]<wZV}.  
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x#{.mN  
try{ =icynW^Fr  
URL url = new URL(sURL); z3:tSjF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T[YGQT|B  
httpConnection.setRequestProperty("User-Agent","NetFox"); +Ks! 9d*k<  
String sProperty = "bytes="+nStartPos+"-"; nmZJ%n  
httpConnection.setRequestProperty("RANGE",sProperty); (NBq!;_2,x  
Utility.log(sProperty); {b6$F[e  
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InputStream input = httpConnection.getInputStream(); M@/Hd0$  
//logResponseHead(httpConnection); KLn.v
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;{k`nv_6  
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byte[] b = new byte[1024]; E{Ux|r~  
int nRead; _v9P0W^.7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p7pJ90~E  
{ Y@Zv5
2,  
nStartPos += fileAccessI.write(b,0,nRead);  \tWFz(  
//if(nThreadID == 1) |#
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c)tG1|Og]  
} ?{ 0MF  
>$yqx1=jW  
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Utility.log("Thread " + nThreadID + " is over!"); C<.Ny,U  
bDownOver = true; >[ox|_o  
//nPos = fileAccessI.write (b,0,nRead); ?Gq|OT8  
} &~xzp^&  
catch(Exception e){e.printStackTrace ();} =R
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} sX~ `Vn&  
}  0"VL6$  
~j`;$o  
7jZ=+2  
//打印回应的头信息 4{s3S2f=  
public void logResponseHead(HttpURLConnection con) 2V1|b`b#4  
{ }op0`-Xb  
for(int i=1;;i++) [JY1|N  
{ w)hH8jx{  
String header=con.getHeaderFieldKey(i); #0WGSIht<  
if(header!=null) {iI"Lt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i@C1}o-/  
Utility.log(header+" : "+con.getHeaderField(header)); : ;nvqbd  
else U;7Cmti"  
break; K6=i\   
} VR@V3 ~  
} FKOTv2  
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public void splitterStop() 02lI-xHe  
{ k-$5H~(PZ  
bStop = true; g.3a5#t  
} KL8G2"Z  
2k}" 52  
)NoNgU\7!  
} (W~')A"hC'  
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/* 5@YrtZI  
**FileAccess.java }, < dGmkx  
*//文件访问(定位，写) Rd?8LLz  
package NetFox; |#_F  
import java.io.*; s+@+<QE  
-A?6)ggf.  
m5wfQ_}}ss  
public class FileAccessI implements Serializable{ mzh8<w?ns  
m~[4eH,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H+ P&} 3  
RandomAccessFile oSavedFile; W:s>?(6?  
long nPos;
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public FileAccessI() throws IOException C#^V<:9  
{ EpX.{B@B_[  
this("",0); 4O TuX!  
} " vW4"R6  
;i)NP X  
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public FileAccessI(String sName,long nPos) throws IOException Ihd{@6m  
{ N)kZ2|oD  
oSavedFile = new RandomAccessFile(sName,"rw"); t",=]k  
this.nPos = nPos; FZt a  
oSavedFile.seek(nPos); 6n|R<DO%\  
} B<p-
qPR K  
x1@`\r#0  
n=z=%T6  
public synchronized int write(byte[] b,int nStart,int nLen) ]^e4coC  
{ CFLWo1  
int n = -1; m-<"`:+  
try{ 'n>v}__&|  
oSavedFile.write(b,nStart,nLen); vKcZgIR  
n = nLen; 'ie+/O@G  
} T{A_]2 G  
catch(IOException e) TFQX}kr]  
{ b1*5#2rs.  
e.printStackTrace (); hT=6XO od4  
} pie,^-_.g  
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return n; Vr<eU>W  
} 3pk=c-x  
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} [z2jR(+`U  
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/* |z+K]R8_  
**SiteInfoBean.java l0v]+>1i:  
*/ f\|R<3 L  
package NetFox; F?!X<N
{  
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J"$Y`;  
public class SiteInfoBean { Z ? F*Z0y  
vNA~EV02  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path Qy!;RaA3T  
private String sFileName; //Saved File's Name  |Ok=aV7  
private int nSplitter; //Count of Splited Downloading File oIJ.Tv@N(  
A*a:#'"*N  
0dKv%X#\  
public SiteInfoBean() 7`G FtX}  
{//nSplitter的缺省值为5 `{B<|W$=  
//default value of nSplitter is 5 sN8)p%'Lg  
this("","","",5);  ds#om2)  
} 9i?Q=Vuc~<  
pR,eus;8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2," (  
{ {SOy-  
sSiteURL= sURL; Rnd.<jz+Y  
sFilePath = sPath; mC,:.d  
sFileName = sName; 2Sha&Z*CE  
this.nSplitter = nSpiltter; \G~<O071  
~\QN.a  
|/M^q{h&7s  
} b-"kcl
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mR1|8H!f  
:rdnb=n  
public String getSSiteURL() Yo^9Y@WDW  
{ C}D\^(nLu.  
return sSiteURL; z7PmyU >  
} q(nPI  
l.Y
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8ED}!;ZU  
public void setSSiteURL(String value) Es^=&2''  
{ TEEt]R-y  
sSiteURL = value; ,mY3oyu  
} rF:l
+I]  
Vgg'5o&.  
$;Nw_S@  
public String getSFilePath() 9u^yEqG`  
{ UVlXDebl  
return sFilePath; ySP%i6!au  
} Frd`u.I  
D3.$Vl,.  
G1?m}{D)  
public void setSFilePath(String value) SbX#$; ks~  
{ P6~&,a  
sFilePath = value; j3$\+<m]  
} Ae3=o8p  
8n~
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} >z
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public String getSFileName() &f_ua)cyY  
{ }u&,;]  
return sFileName; -q")qNt.  
} 1!"iN~  
dZ;rn!dg>  
'6zk>rN  
public void setSFileName(String value) 9'I$8Su  
{ $?M$^-(e  
sFileName = value; mgL{t"$c  
} V=-hqo(  

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FS^ie|8{D-  
public int getNSplitter() %&\DCAFk  
{ u[b0MNE~  
return nSplitter; .'Rz tBv  
} ELa:yIl0  
JM>4m)h#  
y-R:-K XH=  
public void setNSplitter(int nCount) b[;Zl<  
{ _2p D  
nSplitter = nCount; %YV3-W8S0  
} 3^2P7$W=   
} Y. 1dk  
j"wbq-n,7  
F0 ^kUyF|  
/* nX\Q{R2  
**Utility.java [D= KI&@&O  
*/ GGF;4  
package NetFox; EhK~S(r^  
1WJ%n;  
,mm9X\ '  
public class Utility { s3+6Z~g'B  
#1VejeTi  
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public Utility() r3mQoTvnv  
{ C#@>osC  
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} MB3 0.V/\  
IKVS7m  
//线程睡眠 ?CHFy2%Y  
public static void sleep(int nSecond) Zrm!,qs  
{ n}!D)Gx  
try{ <h[l)-86  
Thread.sleep(nSecond); u(bPdf@kz  
} O$$$1VHYo  
catch(Exception e) b]XDfe  
{ D! $4  
e.printStackTrace (); 6,:`esl  
} u8sK~1CPf  
} \r^*4P,,  
C$#X6Q!,  
//日志 bP3S{Jt-|  
public static void log(String sMsg) &Rxy]kBA  
{ ;&?l1Vu  
System.err.println(sMsg); ^iz2=}Q8  
} 9!UFLZR  
81&5g'  
r5(-c]E7  
public static void log(int sMsg) x39n7+j4  
{ l!9G  
System.err.println(sMsg); N%" /mcO  
} Mg^.~8\de  
} w$)E#|i  
8j%hxAV$  
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/* \[F4ooe  
**TestMethod.java .>bvI1  
*/ s\#eD0|  
package NetFox; nd?R|._R  
&]euL:C  
+'f38D*  
public class TestMethod { m(c5g[6nO  
e Zb8x  
*3r{s'm  
public TestMethod() a eo/4  
{ ///xx/weblogic60b2_win.exe BR[f{)a5  
try{ 6yRxb(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +ziQ]r2g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r-SQk>Y}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '@Q aeFm  
fileFetch.start(); ecl$z6'c  
} }iF"&b0n"  
catch(Exception e){e.printStackTrace ();} >xa k  
1XvB,DhJ  
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} 2 - ?  
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public static void main(String[] args) Mk"V%)1k  
{ $xU5vCwAo  
new TestMethod(); |Y42ZOK0  
} SOPQg?'n=V  
} I];Hx'/<~  
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