http断点续传简单实现（java)

/* [ME}Cv`?<E  
**SiteFileFetch.java dSOlD/c  
*/ I#|ocz  
package NetFox; .q0218l:dF  
import java.io.*; w
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import java.net.*; \4h>2y  
w=f0*$ue+w  
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public class SiteFileFetch extends Thread { @gt)P4yE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [_y9"MMwn  
long[] nStartPos; //开始位置 .UM<a Ik  
long[] nEndPos; //结束位置 "sF Xl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LXHwX*`Y  
long nFileLength; //文件长度 7"ylN"syZ
 
boolean bFirst = true; //是否第一次取文件 ,M\j%3
 
boolean bStop = false; //停止标志 J0^{,eY<  
File tmpFile; //文件下载的临时信息 cPpu  
DataOutputStream output; //输出到文件的输出流 5cD XWF  
h [nH<m  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n?'d|h  
public SiteFileFetch(SiteInfoBean bean) throws IOException &EAk z  
{ [096CK  
siteInfoBean = bean; ]>tq|R78  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;yF[2P ;
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0o=!j3RjH  
if(tmpFile.exists ()) FE/$(7rM  
{ z>4D~HX  
bFirst = false; F\>oxttS1
 
read_nPos(); ZlthYuJ  
} K!3{M!B  
else Y)$52m5rM  
{ QJx9I_  
nStartPos = new long[bean.getNSplitter()]; MV%Xhfk  
nEndPos = new long[bean.getNSplitter()]; )-=2w-ZX  
} {mNdL J  
"XCU'_k=  
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{IJ-4>  
} \% }raI;Y@  
!G7h9CF|{  
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public void run() >@^<S_KVh  
{ RnHQq'J|\  
//获得文件长度 hlX>K  
//分割文件 ($c`s8mp  
//实例FileSplitterFetch |y.zocBj  
//启动FileSplitterFetch线程 r=h8oUNEJ*  
//等待子线程返回 K!GUv{fp  
try{ Z[Wlyb0  
if(bFirst) |5W8Q|>%  
{ Yt -W1vl  
nFileLength = getFileSize(); @4;&hP2Z:  
if(nFileLength == -1) @gNpJB]V  
{ h~ $&  
System.err.println("File Length is not known!"); K} +S+ *_  
} {5>3;.  
else if(nFileLength == -2) - $%jb2  
{ r,5-XB  
System.err.println("File is not access!"); 7'Lp8  
} aC`Li^  
else Bb~5& @M|N  
{ d+tj%7  
for(int i=0;i<nStartPos.length;i++) ji}#MBac  
{ ASR-a't6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d7E7f  
} djUihcqA`  
for(int i=0;i<nEndPos.length-1;i++) *2`:VFEV  
{ ^%;"[r  
nEndPos = nStartPos[i+1]; ?4,@, ae&  
} 5? Wg%@  
nEndPos[nEndPos.length-1] = nFileLength; s}wO7Df=+  
} :AZp}  
} rsWQHHkO  
)]73S@P(=  
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//启动子线程 ^]VcxKUJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h6g:(3t6m  
for(int i=0;i<nStartPos.length;i++) L/BHexOB  
{ !}ilN 1>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P@C c]Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zhX;6= X2  
nStartPos,nEndPos,i); 0C]4~F x~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ \l HI  
fileSplitterFetch.start(); K5{{:NR$  
} QP:9%f>=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Rb#/qkk/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `$at9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mf}\s]_c  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); I]jX7.fx  
"J& (:(:  
k52QaMKa~A  
//等待子线程结束 &3I$8v|!?  
//int count = 0; usy,V"{  
//是否结束while循环 UeA2c_ 5  
boolean breakWhile = false; zj{(p Z1  
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while(!bStop) uoHqL IpQ  
{ .
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write_nPos(); eES'}[W>  
Utility.sleep(500); as(*B-_n~  
breakWhile = true; jn^fgH?  
Oxv+1Ub<Dv  
^7Lk-a7gp  
for(int i=0;i<nStartPos.length;i++) !Av1Leb9$  
{ >yKpM }6l{  
if(!fileSplitterFetch.bDownOver) EL7T'zJ$  
{ .a,(pq Jg  
breakWhile = false; F$h'p4$T  
break; &$F[/[Ds+  
} @0|nq9l1  
} !lhFKb;  
if(breakWhile) <GaT|Hhc=  
break; kon5+g9q  
>! oF0R_<  
:G}DAUFN  
//count++; 4[1k\  
//if(count>4) lUHtjr  
// siteStop(); vL$|9|W(  
}  %}h`+L  
"y$ qrN-  
9#Y2`pT  
System.err.println("文件下载结束！"); zmb
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} E?Cj/o  
catch(Exception e){e.printStackTrace ();} J)*8|E9P  
} :
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Hd0Xx}3&  
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//获得文件长度 ufPCx|x~  
public long getFileSize() H* /&A9("  
{ <Y>3  
int nFileLength = -1; ,eXFN?CB  
try{ (@q3^)I4  
URL url = new URL(siteInfoBean.getSSiteURL()); 1~@|eWr|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )~}PgbZ^  
httpConnection.setRequestProperty("User-Agent","NetFox"); +9zA^0  
nLJBq)i  
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int responseCode=httpConnection.getResponseCode(); p+[}Hxx=  
if(responseCode>=400) u s`}  
{ U Du~2%  
processErrorCode(responseCode); HN68!v}C|  
return -2; //-2 represent access is error ;&kn"b}G;  
} iNJAZ6@+  
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String sHeader; qlUzr.^-  
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$  
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for(int i=1;;i++) h<Wg
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{ ,QvYTJ{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F7T
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//Utility.log(in.readLine()); ]fE3s{y &-  
sHeader=httpConnection.getHeaderFieldKey(i); p=B?/Sqa  
if(sHeader!=null)
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{ -B9S}NPo  
if(sHeader.equals("Content-Length")) q- :4=vkn  
{ a#y{pT2 b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dB3N%pB^  
break; 8=F%+  
} SF< [FM%1  
} "PzP;Br  
else DA=1KaJ.  
break; B< hEx@  
} gxmc|  
} oZ:{@=  
catch(IOException e){e.printStackTrace ();} =}R~0|^  
catch(Exception e){e.printStackTrace ();} W:O0}  
/^2CGcT(  
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Utility.log(nFileLength); s$GF 95^  
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return nFileLength; C:GvP>  
} fxtxu?A>  
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w$>3pQ8
d  
//保存下载信息（文件指针位置） jBpVxv  
private void write_nPos() }
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{ /DO'IHC.o  
try{ Rla4L`X;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kcS6_l  
output.writeInt(nStartPos.length); 3LW[H+k  
for(int i=0;i<nStartPos.length;i++) *jF#^=  
{ U$'y_}V  
// output.writeLong(nPos); !O{z 3W  
output.writeLong(fileSplitterFetch.nStartPos); <HQ&-jx  
output.writeLong(fileSplitterFetch.nEndPos); T//S,  
} Df@/cT  
output.close(); yvxl_*Ds8  
} |scUo~  
catch(IOException e){e.printStackTrace ();} |ym%| B  
catch(Exception e){e.printStackTrace ();} H/J<Pd$p  
} U3F3((EYJ  
vg(K$o{BT  
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//读取保存的下载信息（文件指针位置） )ooWQ-%P  
private void read_nPos() "H1:0p  
{ W-D[z#)/Y  
try{ QlD6i-a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~lw<799F6  
int nCount = input.readInt(); U9#WN.noG  
nStartPos = new long[nCount]; 5AOfp2O  
nEndPos = new long[nCount]; 2OalAY6RS  
for(int i=0;i<nStartPos.length;i++) J#7y< s  
{ @!\K>G >9[  
nStartPos = input.readLong(); -0 0}if7  
nEndPos = input.readLong(); !kXeO6X@m  
} G9RP^  
input.close(); IKcKRw/O$  
} ;fGx;D  
catch(IOException e){e.printStackTrace ();} U)[ty@zyF  
catch(Exception e){e.printStackTrace ();} y
 $V[_TN  
} LC-)'Z9}5  
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private void processErrorCode(int nErrorCode) s, XM9h>P4  
{ Y8ehmz|g]J  
System.err.println("Error Code : " + nErrorCode); ez*j
jm  
} iP "EA8  
=nVmthGw  
6vp0*ww  
//停止文件下载 H?U't 09  
public void siteStop() <y>:B}9'  
{ )i!^]|$  
bStop = true; PayV,8   
for(int i=0;i<nStartPos.length;i++) 7>-yaL{  
fileSplitterFetch.splitterStop(); %j{.0H  
:'*DMW~  
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} k/lFRi-i  
} I]uhi{\C  
//负责部分文件的抓取 np6HUH  
**FileSplitterFetch.java ]}2Ztr)zZ  
*/ nY^Nbh0  
package NetFox; '[Gm8K5  
Fu)Th|5GZ  
arh@`'Q  
import java.io.*;  @E_zR  
import java.net.*; E _iO@  
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public class FileSplitterFetch extends Thread { 7GZq|M_:y  
G|9B)`S  
z{?
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String sURL; //File URL J_xG}d  
long nStartPos; //File Snippet Start Position T:!MBWYe|  
long nEndPos; //File Snippet End Position 509Q0 [k  
int nThreadID; //Thread's ID QnK
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boolean bDownOver = false; //Downing is over _Bk U+=|J  
boolean bStop = false; //Stop identical BUC,M:J+H  
FileAccessI fileAccessI = null; //File Access interface tWD|qg_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QzthTX<  
{ .>]N+:O  
this.sURL = sURL; OVswt  
this.nStartPos = nStart; R^P_{_I*"  
this.nEndPos = nEnd; 8$}OS-  
nThreadID = id; 'b[0ci:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #*
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} ^7u#30,}3~  
(5`T+pAsV  
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public void run() `WlE| G[  
{ /f3m)pT  
while(nStartPos < nEndPos && !bStop) Alz~-hqQ  
{ @{}rG8  
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try{ 'G#SLqZy  
URL url = new URL(sURL); A=`*r*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <qY5SV,  
httpConnection.setRequestProperty("User-Agent","NetFox"); crn k|o  
String sProperty = "bytes="+nStartPos+"-"; *fhX*e8y  
httpConnection.setRequestProperty("RANGE",sProperty); kO ![X^V  
Utility.log(sProperty); 8H $#+^lW  
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InputStream input = httpConnection.getInputStream(); NWKi ()nA%  
//logResponseHead(httpConnection); :ba/W&-d  
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p
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byte[] b = new byte[1024]; 8(A{;9^g  
int nRead; Q}P-$X+/ n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "#S>I8d  
{ e@jfIF0=}  
nStartPos += fileAccessI.write(b,0,nRead); _D-Riu>#J  
//if(nThreadID == 1) m6U8)!)T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s~$zWx@v  
} =`p&h}h-L  
PDC]wZd/  
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Utility.log("Thread " + nThreadID + " is over!"); %f!iHo+Z  
bDownOver = true; 7~vqf3ON4J  
//nPos = fileAccessI.write (b,0,nRead); ]!Zty[  
} f\}22}/  
catch(Exception e){e.printStackTrace ();} pFIecca w  
} 1xTTJyoq  
} YIOR$  
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//打印回应的头信息 J}@GKNm  
public void logResponseHead(HttpURLConnection con) %h+uD^^$  
{ +X^4; &  
for(int i=1;;i++) Efr&12YSS  
{ >L[lV_M_>
 
String header=con.getHeaderFieldKey(i); C1QWU5c v  
if(header!=null) ZvH{wt   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OoaY  
Utility.log(header+" : "+con.getHeaderField(header)); v~5<:0dL  
else =Ahw%`/&}]  
break; v*r9j8
 
} grbTcLSF  
} "$8w.C  
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public void splitterStop() 3qo e^e  
{ o}~3JBnT  
bStop = true; yWHne~!  
} X47Ol  
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mo9$NGM&}  
} ;0j*>fb\q7  
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/* K-4tdC3  
**FileAccess.java 0QoLS|voA/  
*//文件访问(定位，写) d@>\E/zA  
package NetFox; }ywi"k4>  
import java.io.*; ./.=Rw  
:[?!\m%
0  
rzV"Dm$'  
public class FileAccessI implements Serializable{ sqG`"O4W  
J@` 8(\(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DHzkRCM
 
RandomAccessFile oSavedFile; 7;xK
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long nPos; bi,mM,N/  
J @B4 R&V  
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public FileAccessI() throws IOException 1Z:R,\+L  
{ +/q0Y`v  
this("",0); yW>RRE;  
} J3&Sj{ o  
JS7dsO0;  
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public FileAccessI(String sName,long nPos) throws IOException O+FBQiv  
{ N84qcc  
oSavedFile = new RandomAccessFile(sName,"rw"); C BlXC7_Mi  
this.nPos = nPos; gj;@?o0  
oSavedFile.seek(nPos); wOcg4HlW  
} )E`+BH  
oKiD8':  
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public synchronized int write(byte[] b,int nStart,int nLen) !4B_$6US  
{ STB-guia5  
int n = -1; mJ$Htyr  
try{ CB]l[hM$  
oSavedFile.write(b,nStart,nLen); T*\$<-^
 
n = nLen; <[9?Rj@  
} (nz}J)T&  
catch(IOException e) :c<*%*e  
{ SG`)PW?  
e.printStackTrace (); #eLN1q&Z  
} OPiaG!3<  
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:gaETr  
return n; VN+\>j-  
} w, 7Cr  
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p1^
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} M5u_2;3  
4:`[qE3  
raHVkE{<  
/* r=0j7^B#  
**SiteInfoBean.java ,D8&
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*/ $WClpvVj  
package NetFox; * gHCy4u{  
nNs .,J)  
[`9^QEj  
public class SiteInfoBean { *;X-\6  
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private String sSiteURL; //Site's URL xFX&9^Uk  
private String sFilePath; //Saved File's Path ['t8C  
private String sFileName; //Saved File's Name 6KB^w0oA  
private int nSplitter; //Count of Splited Downloading File /f]/8b g>  
K @C4*?P  
hiIyaWU  
public SiteInfoBean() ,`"K  
{//nSplitter的缺省值为5 9'X@@6b*'  
//default value of nSplitter is 5 _XWnS9  
this("","","",5); <S{7Ro  
} e?1KbJ?.  
e&ts\0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '$*[SauAG  
{ D&f!( n  
sSiteURL= sURL; %r P !  
sFilePath = sPath; WP!il(Gr  
sFileName = sName; F-tFet  
this.nSplitter = nSpiltter; dm 2EH  
,\}k~ U99  
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} ;L$,gn5H  
d.I%k1`(  
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public String getSSiteURL() #@q1Ko!NZ  
{ 1~L
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return sSiteURL; TR?Bvy2s:g  
} FR(QFt!g  
w_!%'9m>  
/]g>#J%b  
public void setSSiteURL(String value) S%{lJYwXt  
{ UI_v3c3b  
sSiteURL = value; FNlx1U[  
} yeNvQG  
qZP:@r"  
j^{b^!4~}  
public String getSFilePath() 01o [!nT  
{ %VS 2M #f  
return sFilePath; c l9$g7  
} SlT7L||Ww  
;tXY =  
;xI0\a7  
public void setSFilePath(String value) $i -zMa  
{ df yrn%^Ia  
sFilePath = value; #XfT1  
} Yq{jEatY{/  
&rcdr+'  
s4N,^_j  
public String getSFileName() xlk5Gob*  
{ ;8uHRcdQ  
return sFileName; E;$$+rA  
} ]y}Zi/zh  
:k\}Ik  
<oQ6ZX  
public void setSFileName(String value) /0-\ek ye  
{ }\EL;sT  
sFileName = value; lZBv\JE  
} Gg}t-_M  
xmO
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1j+eD:d'  
public int getNSplitter() \:h0w;34O  
{ ?o8a_9+  
return nSplitter; 3+j^E6@  
} >ks3WMm  
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kM,@[V  
public void setNSplitter(int nCount) 0+rW;-
_(  
{ j+ I*Xw  
nSplitter = nCount; =^#0.  
} g(1"GKg3K  
} 51z/  
3#B@83C0Z  
fH; |Rm  
/* t={poQC~  
**Utility.java :)j7U3u  
*/ !#C)99L"F  
package NetFox; n00z8B1j(l  
eXc[3ceUr  
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public class Utility { f^~2^p 1te  
3|jn,?K)N  
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public Utility() .a5X*M]  
{ )Gmb?!/^  
3mybG%39  
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} w{~" ;[@  
1R*1BStc  
//线程睡眠 QP'qG@j[:  
public static void sleep(int nSecond) 9OH.&g  
{ >}mNi:6xq  
try{ dWMccn;-m  
Thread.sleep(nSecond); 3Nc'3NPQ'  
} [1e.i  
catch(Exception e) $x/J+9Ww  
{ 3Sk5I%  
e.printStackTrace (); gNG.l  
} 9GtLMpy  
} makaI0M  
U-ERhm>uk  
//日志 kja4!_d  
public static void log(String sMsg) 6V+V zDo  
{ =P1RdyP  
System.err.println(sMsg); ?U=mcdqd  
} }F~f&<GX6  
i[mC3ghM6,  
!'+\]eA  
public static void log(int sMsg) <##|311o  
{ kB
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System.err.println(sMsg); C+DG+_%V*S  
} _xa}B,H  
} ex{)mE4Cd  
F
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k>7gy?Y!K<  
/* u}^a^B$  
**TestMethod.java kx:c*3q.k  
*/ S_a :ML<  
package NetFox; 8moUK3w  
Cm99?K  
l# }As.o}  
public class TestMethod { :PHUsy  
`^?}s-H+  
)Uc$t${en  
public TestMethod() !."Izz/  
{ ///xx/weblogic60b2_win.exe ]r"31.w(  
try{ ~GAlNIv]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h<+PP]l=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -7&^jP\,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?T tQZ  
fileFetch.start(); dl7Riw-J  
} Q]yV:7  
catch(Exception e){e.printStackTrace ();} wgC??Be;ut  
lpIteZw:  
l
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} K(%dcUGDK>  
5cPSv?x^F@  
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public static void main(String[] args) p7%0hLW  
{ :(5]Z^  
new TestMethod(); er&uC4Y]a  
} :!r9 =N9  
} Bu*W1w\  
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