http断点续传简单实现（java)

/* T]De{nHu  
**SiteFileFetch.java <R7{W"QTA)  
*/ Zo<)r2|O.  
package NetFox; <a"(B*bBd  
import java.io.*; U3{<+vSR`  
import java.net.*; Z<i}XCE  
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public class SiteFileFetch extends Thread { 2R&\qZ<  

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SiteInfoBean siteInfoBean = null; //文件信息Bean r'OqG^6JFN  
long[] nStartPos; //开始位置 SUc%dpXZa  
long[] nEndPos; //结束位置 UH!(`Z\C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W~
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long nFileLength; //文件长度 W#F9Qw  
boolean bFirst = true; //是否第一次取文件 Hh1_z
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boolean bStop = false; //停止标志 XGB\rfvS  
File tmpFile; //文件下载的临时信息 =wh[D$n$~  
DataOutputStream output; //输出到文件的输出流 e_=K0fFz  
@wR3L:@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kkq1:\pZ]a  
public SiteFileFetch(SiteInfoBean bean) throws IOException ab2FK
 
{ ]bY|>q  
siteInfoBean = bean; GOc   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MT-T
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zk=,`sBC  
if(tmpFile.exists ()) iwK.*0
7+  
{ <gF]9%2E  
bFirst = false; (bb!VVA  
read_nPos(); *]]Zpa6  
} 7[1L
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else SboHo({5VA  
{ /}m)FaAi  
nStartPos = new long[bean.getNSplitter()]; sF {,n0<8  
nEndPos = new long[bean.getNSplitter()]; 0SI@`C*1o  
} 1B4Qj`:+0  
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} ,.<mj !YE  
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public void run() 1C
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{ 5s[nE\oaG  
//获得文件长度 J#(AX6  
//分割文件 ]{1{XIF  
//实例FileSplitterFetch `MU~N_  
//启动FileSplitterFetch线程 $,}jz.R@  
//等待子线程返回 'zI(OnIS  
try{ p/ ITg  
if(bFirst) "#~>q(
4^  
{ w5%Yi{  
nFileLength = getFileSize(); " @D  
if(nFileLength == -1) TPN+jK  
{ jKq*@o~}  
System.err.println("File Length is not known!"); $%~JG(  
} OD8 fn  
else if(nFileLength == -2) uN`/&_$c  
{ 8qyEHUN2q  
System.err.println("File is not access!"); UMGiJO\yH  
} 0fOhCxtL@  
else ]*=4>(F[  
{ gA2Wo+\^bq  
for(int i=0;i<nStartPos.length;i++) MKBDWLCB  
{ c2P}P* _  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JXc.?{LL  
} 3uuIISK  
for(int i=0;i<nEndPos.length-1;i++) m{Q #f\<  
{ ;xwcK-A  
nEndPos = nStartPos[i+1]; X!]v4ma`  
} 9nG^_.}|  
nEndPos[nEndPos.length-1] = nFileLength; 2o SM|  
} XO <0;9|  
} h5P_kZJ  
;XN|dq  
"8f4s|@3  
//启动子线程 P6v ANL-B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {M**a  
for(int i=0;i<nStartPos.length;i++) 1&dtq,|N  
{ E=8'!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zy,SL |6:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 83vMj$P  
nStartPos,nEndPos,i); `dvg5qQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3}|[<^$  
fileSplitterFetch.start(); ,\M77V  
} YlrN^rO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K0gQr.J53  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]X6<yzu&+l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;%e)t[5  
nEndPos = " + nFileLength); 4LTm&+(5  
// fileSplitterFetch[nPos.length-1].start(); %,T*[d&i  
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'7?Y+R@|L  
//等待子线程结束 ,:t,$A  
//int count = 0; vJ&_-CX   
//是否结束while循环 k'o[iKlu  
boolean breakWhile = false; (ghI$oH  
1B;2 ~2X  
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while(!bStop) A*OqUq/H`;  
{ -#ZLu.  
write_nPos(); *`H*@2  
Utility.sleep(500); ,6>3aD1w~q  
breakWhile = true; =z'(FP5!0  
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for(int i=0;i<nStartPos.length;i++) TE Z%|5(]  
{ F vkyp"W3  
if(!fileSplitterFetch.bDownOver) wKM9fs  
{ =|?`5!A  
breakWhile = false; P73GH  
break; qX@e+&4P0  
} /PwiZA3sA  
} %/A>'p,~  
if(breakWhile) 16L YVvmW  
break; O(-p md,  
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5MnP6(3$  
//count++; -.h)CM@L  
//if(count>4)  vD#U+  
// siteStop(); (=!At)
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} leC!Yj  
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System.err.println("文件下载结束！"); ,j_js8r  
} lx|Aw@C3~  
catch(Exception e){e.printStackTrace ();} R%jOgZG  
} z x-[@G  
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>?@5>wF  
//获得文件长度 NW[K/`-CTH  
public long getFileSize() 0"R>:f}  
{ jYVs\h6  
int nFileLength = -1; H7+"BWc  
try{ bWo  
URL url = new URL(siteInfoBean.getSSiteURL()); M_E,pg=rWI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3'z$@;Ev+  
httpConnection.setRequestProperty("User-Agent","NetFox"); ogFo/TKM  
&Sd5]r@+  
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int responseCode=httpConnection.getResponseCode(); vqeH<$WHvy  
if(responseCode>=400) *p(_="J,  
{ $}&a*c>  
processErrorCode(responseCode); bLg!LZ|S0s  
return -2; //-2 represent access is error U"r*kO%  
} _WZx].|A=  
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String sHeader; Jinh#iar  
!{-W%=Kf  
.
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for(int i=1;;i++) in1rDN%Vi  
{ D)-LZbPa  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jt[ug26  
//Utility.log(in.readLine()); |?88EG@05  
sHeader=httpConnection.getHeaderFieldKey(i); Ge2Klyi  
if(sHeader!=null) 0S5xmEzop  
{ 1?.CXqK  
if(sHeader.equals("Content-Length")) *HD(\;i-$  
{ M`&t=0D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -PPwX~;!  
break; Z,)H f  
} }eLApFHEDg  
} GKoYT{6  
else |XB<vj07G  
break; *F( qg%1+  
} 'UX^]  
} ~<_#%R!  
catch(IOException e){e.printStackTrace ();} S>dHBR#AD  
catch(Exception e){e.printStackTrace ();} V48_aL  
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Utility.log(nFileLength); pb97S^K[  
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return nFileLength; lR %#R  
} A$wC!P|;  
Y!M0JSaM  
%G!!0V!  
//保存下载信息（文件指针位置） 3P0z$jh"H  
private void write_nPos() \aJ>?   
{ Pn9".  
try{ Vo"G@W)lZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r-T1^u  
output.writeInt(nStartPos.length); `<tRfl}qs  
for(int i=0;i<nStartPos.length;i++) kqeEm{I  
{ c^w^'<  
// output.writeLong(nPos); 4pL'c@'  
output.writeLong(fileSplitterFetch.nStartPos); vl/!w2  
output.writeLong(fileSplitterFetch.nEndPos); }[eUAGhDU  
} Zz} o t  
output.close(); PY.HZ/#d  
} Kl.*Q  
catch(IOException e){e.printStackTrace ();} G `|7NL   
catch(Exception e){e.printStackTrace ();} t`6]eRR  
} $ #!oejLD  
;}Jv4Z  
{gzQ/|}#z-  
//读取保存的下载信息（文件指针位置） Q9cSrU[$  
private void read_nPos() ,[ 2N3iH  
{ cpk\;1&t  
try{ =Z.0-C>W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Sd6O?&(  
int nCount = input.readInt(); 7Q!ksp  
nStartPos = new long[nCount]; %i?  
nEndPos = new long[nCount]; Py*WHHO  
for(int i=0;i<nStartPos.length;i++) bg|$1ue  
{ j*QdD\)  
nStartPos = input.readLong(); S
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nEndPos = input.readLong(); )L&y@dy)  
} H{=]94  
input.close(); q&:7R .Ci  
} fExFpR,`  
catch(IOException e){e.printStackTrace ();} &~eCDlX/  
catch(Exception e){e.printStackTrace ();} [lIX&!T"  
} d>Tv?'o`q  
<7y/)b@  
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private void processErrorCode(int nErrorCode) V~PGmn[V  
{ E#P#{_BR^  
System.err.println("Error Code : " + nErrorCode); ;C-ds  
} }h1BAKg  
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!Mw/j`*  
//停止文件下载 ,xU#uyB  
public void siteStop() S(3h{Y"#  
{ E0qJ.v  
bStop = true; 3sV$#l P  
for(int i=0;i<nStartPos.length;i++) &7'=t6  
fileSplitterFetch.splitterStop(); F+Kju2  
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7s%D(;W_Mo  
} uyEk1)HC  
} QV."ZhL5=  
//负责部分文件的抓取 7y^)n<'co  
**FileSplitterFetch.java npeL1zO-$  
*/ O$z"`'&j#  
package NetFox; d%}?%VH  
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"6]oi*_8  
import java.io.*; C+\z$/q  
import java.net.*; MY{Kq;FvRP  
->qRGUW  
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public class FileSplitterFetch extends Thread { +_ehzo97  
JAHmmNlW  
k|xmZA*  
String sURL; //File URL y:\<FLR}j  
long nStartPos; //File Snippet Start Position T}\
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long nEndPos; //File Snippet End Position !=30
s;-  
int nThreadID; //Thread's ID ~98q1HgS]D  
boolean bDownOver = false; //Downing is over #U0| j?!D  
boolean bStop = false; //Stop identical BUZ74  
FileAccessI fileAccessI = null; //File Access interface [e,xC!2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7VfXE/  
{ H`<u2fo|p  
this.sURL = sURL; 1<h@^s;  
this.nStartPos = nStart; /7B3z}rd  
this.nEndPos = nEnd; +Q"s!\5  
nThreadID = id; &K!0yR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _&(Wz0  
} 7/&taw%i  
#l>r9Z71  
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public void run() <O) if^  
{ ;xq
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while(nStartPos < nEndPos && !bStop) @<P;F  
{ )j]f ]8  
9Cd=^Im5  
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try{ E>@]"O)=M,  
URL url = new URL(sURL); tM@%EO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KdiJ'K.  
httpConnection.setRequestProperty("User-Agent","NetFox"); a%y*e+oM  
String sProperty = "bytes="+nStartPos+"-"; NjS<DzKhK  
httpConnection.setRequestProperty("RANGE",sProperty); /  !h<+  
Utility.log(sProperty); pV<K=;:x>  
?`vGpi~  
860y9wzU  
InputStream input = httpConnection.getInputStream(); =Q;dYx%I5  
//logResponseHead(httpConnection); 3I'7+?@@l  
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byte[] b = new byte[1024]; xN
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int nRead; |1kA6/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @6_w{6:b  
{ CZy!nR!  
nStartPos += fileAccessI.write(b,0,nRead); [)X(Qtk  
//if(nThreadID == 1) DM6(8df(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y2g)*T!m  
} rU>l(O'b  
_ y'g11 \  
;|=5)KE  
Utility.log("Thread " + nThreadID + " is over!"); O&CY9 2)Lk  
bDownOver = true; REc90v2"  
//nPos = fileAccessI.write (b,0,nRead); =H-BsX?P  
} /5KY6XxR  
catch(Exception e){e.printStackTrace ();} oeVI 6-_S  
} 0<-A2O),  
} |p/[sD+M  
9-#=xE9'U  
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//打印回应的头信息 }q_Iep  
public void logResponseHead(HttpURLConnection con) @B)5Ho  
{ v*y,PY1*  
for(int i=1;;i++) 6X2w)cO  
{ 9;gy38.3  
String header=con.getHeaderFieldKey(i); 5[6{
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if(header!=null) 4M$"0}O;[h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hm 0
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Utility.log(header+" : "+con.getHeaderField(header)); K_j*9@  
else L.9@rwfI  
break; \Vj7%ph  
} nKwOSGPQt  
} _B&;z $  
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!y1qd  
public void splitterStop() EwfL.z  
{ w$qdV,s 7  
bStop = true; u~t%GIg  
} [*vR&4mk  
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} P`CQ)o  
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/* VyIM ,glu  
**FileAccess.java bT:;^eG"  
*//文件访问(定位，写) c~Y g(  
package NetFox; KWVl7Kw#e  
import java.io.*; -<\hcV`&  
^x >R #.R  
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public class FileAccessI implements Serializable{ #FGj)pu  
MR":aT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CTB qX  
RandomAccessFile oSavedFile; 30cb+)h(  
long nPos; "f!H[F1~  
zM%2h:*+{  
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public FileAccessI() throws IOException r*Z p-}  
{ pr\OjpvD  
this("",0); 78'3&,+si  
}  N,ihQB5  
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public FileAccessI(String sName,long nPos) throws IOException `g'9)Xf4KT  
{ TwZmZE ?!  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; p?<T _9e  
oSavedFile.seek(nPos); ;:~-=\  
} VPDd*32HC  
G/Yqvu,2!  
# i|pi'Ij  
public synchronized int write(byte[] b,int nStart,int nLen) 2,6|l.WFpE  
{ CVgVyy^  
int n = -1; OYIH**?  
try{ H3|x  
oSavedFile.write(b,nStart,nLen); w2]]##J  
n = nLen; Kb#
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} ^,fMs:  
catch(IOException e) u3vw[k  
{ mm`yu$9gbP  
e.printStackTrace (); ESY\!X:|  
} *edhJUT  
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return n; u85Uy yN  
} &(X-b"2  
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} qJJ~#W)  
&Ht5!zuW,  
vy5SBiK  
/* lT-LOu|  
**SiteInfoBean.java !-|{B3"6  
*/ fJOA5(  
package NetFox; &n2dL->*#  
R`>z>!)  
}woNI  
public class SiteInfoBean { 5PT*b}g@  
5cSqo{|En  
5ma(~5  
private String sSiteURL; //Site's URL g5hMZPOmP  
private String sFilePath; //Saved File's Path ~
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private String sFileName; //Saved File's Name `^CIOCK%  
private int nSplitter; //Count of Splited Downloading File N._&\fHY  
b~EA&dc
 
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public SiteInfoBean() mT#ebeBaf  
{//nSplitter的缺省值为5 >}!})]Xw9  
//default value of nSplitter is 5 D"GQlR  
this("","","",5); ,wH]|`w  
}  5wy3C  
\9jvQV/y  
uY$BZEuAZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t8z=R6zX  
{ (Q][d+} /  
sSiteURL= sURL; 6nHyd<o  
sFilePath = sPath; -@G,Ry-\t  
sFileName = sName; `RLn)a  
this.nSplitter = nSpiltter; !:<n]-U  
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]^DNzqu=@h  
} ~V!gHJ5M  
lX|d:HFtP  
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public String getSSiteURL() ^q)s  
{ l]__!X  
return sSiteURL; u
+,  
} z+qrsT/?L  
_(J/$D  
)Vnqz lI5  
public void setSSiteURL(String value) v?qU/  
{ "~ eF%}.  
sSiteURL = value; `\#J&N  
} !6:
X]  
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&! MV!9$  
public String getSFilePath() ).9m6.%Uk  
{ -jQ
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return sFilePath; 72{Ce7J4  
} DmpG35Jk  
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public void setSFilePath(String value) w>Y!5RnO  
{ &Uu8wFbIJ  
sFilePath = value; :7jDgqn^|i  
} `
oGL==  

h}cR>  
=^S1+B MY-  
public String getSFileName() w{5v*SHl}`  
{ %XAF"J  
return sFileName;  Oa/#2C~  
} jK9#. 0  
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kB $?A8Olu  
public void setSFileName(String value) &3%V%_  
{ MY"8!  
sFileName = value; eg Zb)pP  
} 4vb
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G [$u`mxV^  
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public int getNSplitter() /r@~"Rx'  
{ h;?H4j  
return nSplitter; 1/%g VB8  
} `c%{M4bF\  
;<)<4N"  
)$7-CNWr~  
public void setNSplitter(int nCount) Emx`+9  
{ KBkS>0;X  
nSplitter = nCount; Cqc5jx0)  
} >,)tRQS  
} N=@Nn)  
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q}0xQjpo  
/* Q/<?v!h{  
**Utility.java XpU%09K  
*/ q7ubRak  
package NetFox; oVYW'~OID  
, UiA?7k  
#Z>EX?VS:  
public class Utility { 5x/LHsr=m  
WXX)_L$2  
/7[X_)OG  
public Utility() KR sY `[Y  
{ qxW^\u!<  
"0]s|ys6<  
\:@yfI@  
} HH3Ln+AWg_  
7ajkp+E6  
//线程睡眠 .`Rju|l  
public static void sleep(int nSecond) nYbI =_-  
{ A4`3yy{0-  
try{ z)&ZoSXWc  
Thread.sleep(nSecond); ^7>k:|7-t  
} IMtfi(Y%F  
catch(Exception e) "D1u2>(  
{ ?3|jB?:k  
e.printStackTrace (); 0; BX  
} X[r\ Qa  
} '|^<|S_+K  
nht?58  
//日志 2~(\d\k  
public static void log(String sMsg) E[2>je  
{ $++SF)G1]_  
System.err.println(sMsg); uA~T.b\  
}
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6< O|,7=_  
0JS#{EDh+  
public static void log(int sMsg) O{w'i|  
{ gyf9D]W  
System.err.println(sMsg); ?vr9l7VOi  
} hX&Jq%{oa  
} UK!PMkX  
Ti!<{>  
g6p:1;Evf  
/* n0rAO
kW  
**TestMethod.java '&42E[0P  
*/ K! I]0!:  
package NetFox; `D
~wY^q{  
 "yA=Tw  
7ts`uI<E@7  
public class TestMethod { ,wPvv(b]a  
ywj'S7~A  
5,Hj$v7fe  
public TestMethod() >IFqwh7b  
{ ///xx/weblogic60b2_win.exe :7Jpt3  
try{ D,sb{N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k^C^.[?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?4A$9H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z(g6$Y{  
fileFetch.start(); ~H1ZQ[  
} MR
`lF-|a|  
catch(Exception e){e.printStackTrace ();} 5%1a!MM M  
}I>h<O  
b^q8s4(  
} i}E&mv'  
3Eu;_u_  
$l+DkR+  
public static void main(String[] args) +\/1V`  
{ Wt 1]9{$  
new TestMethod(); #[$zbZ(I>:  
} dJ&f +  
} Ka+N5 T.f  
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