http断点续传简单实现（java)

/* &ntBU]<q  
**SiteFileFetch.java 4aZCFdc  
*/ ~!%0Z9>ap  
package NetFox; xSpC'"   
import java.io.*; k7_I$<YDj  
import java.net.*; Z#`0txCF  
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public class SiteFileFetch extends Thread { 9CUimZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean  *2u E  
long[] nStartPos; //开始位置 8dT'xuch  
long[] nEndPos; //结束位置 :s8A:mx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }\v^+scD  
long nFileLength; //文件长度 5IMSNGS  
boolean bFirst = true; //是否第一次取文件 {g/wY%u=  
boolean bStop = false; //停止标志 hN
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File tmpFile; //文件下载的临时信息 Pn TZ/|  
DataOutputStream output; //输出到文件的输出流 jeN1eM8WI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &J"YsY  
public SiteFileFetch(SiteInfoBean bean) throws IOException h\,5/ )Y  
{ VlW9UF-W  
siteInfoBean = bean; 2]jPv0u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >L2*CV3p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <D/al9  
if(tmpFile.exists ()) D#sf i,O  
{ ].DY"  
bFirst = false; 4 9w=kzo  
read_nPos(); Oo%!>!Lt,  
} % m
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else rb_Z5T  
{ 3_qdJ<,  
nStartPos = new long[bean.getNSplitter()]; 9n}
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nEndPos = new long[bean.getNSplitter()]; }(i(Ar-  
} ;?6>mh(`  
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} 5ouQQ)vA  
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public void run() `ENP=kL(+  
{ ./maY1>T  
//获得文件长度 9EgP9up{6!  
//分割文件 {Qtq7q.  
//实例FileSplitterFetch jW5iqU"{*  
//启动FileSplitterFetch线程 +BB0wY  
//等待子线程返回 eYP=T+  
try{ ]UUI~sFE  
if(bFirst)
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{ (-(*XNC  
nFileLength = getFileSize(); CV^0.  
if(nFileLength == -1) ]xq::a{Oy  
{ ko[TDh$T5  
System.err.println("File Length is not known!"); cb+y9wA  
} QaMDGD  
else if(nFileLength == -2) z}5<$K_U  
{ QP\yaPE  
System.err.println("File is not access!"); \.>.c g  
} g37q/nEv  
else G*\sdBW!k  
{ \REc8nsLy  
for(int i=0;i<nStartPos.length;i++) ^pcRW44K  
{ 9y+[o
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NiTJ}1 l  
} )1_(>|@oi  
for(int i=0;i<nEndPos.length-1;i++) nUqy1(  
{ )Xno|$b5Eo  
nEndPos = nStartPos[i+1]; '0Zm#g  
} k}BDA|\s  
nEndPos[nEndPos.length-1] = nFileLength; ]bfqcmh<  
} N$'>XtO  
} hPPB45^  
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//启动子线程 aYj%w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; XM!M%.0WS  
for(int i=0;i<nStartPos.length;i++) b?k4InXh  
{ a%n'%*0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PPgW ^gj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >ITEd  
nStartPos,nEndPos,i); nO_!:6o".  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }N|\   
fileSplitterFetch.start(); 5Bd(>'ig_  
} 6^ik|k|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DQ5W6W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <3Fz>}V32  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q [:<S/w  
nEndPos = " + nFileLength); R9=K(pOT  
// fileSplitterFetch[nPos.length-1].start(); e`ex]py<C  
!w=,p.?V=  
.Cfp'u%\;  
//等待子线程结束 #11RLvDQd  
//int count = 0; \1{_lynD  
//是否结束while循环 k#jm7 +  
boolean breakWhile = false; 7sguGwg)_  
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while(!bStop) ~>w:;M=sV8  
{ BK*UR+,  
write_nPos(); >t,
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Utility.sleep(500); YE
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breakWhile = true; 1)Eq&ASB  
{_Np<r;j<  
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for(int i=0;i<nStartPos.length;i++) [)iN)$Mv  
{ KT=a(QL  
if(!fileSplitterFetch.bDownOver) y^YVo^3  
{ 2$DSBQEx  
breakWhile = false; BJIFl!w  
break; f\=6I3z  
} 7?"9J`*  
} ]0YDb~UB  
if(breakWhile) AgCs;k&IG  
break; >.@MR<H#5  
/xf.\Z7<  
YR8QO-7 .)  
//count++; D{3fhPNU<b  
//if(count>4) P|v ?
 
// siteStop(); %\l0-RA@<  
} &&*wmnWCS{  
[[$Mh_MD  
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System.err.println("文件下载结束！"); Hq-v@@0 *  
} Uk|9@Auav  
catch(Exception e){e.printStackTrace ();} hvL6zCi  
} :^.u-bHI  
b8e*Pv/  
CL )%p"[x  
//获得文件长度 _UaPwJ  
public long getFileSize() r.Lx%LZ\^  
{ sHF%=Vu  
int nFileLength = -1; '1lx{UzD  
try{ ) _#T c  
URL url = new URL(siteInfoBean.getSSiteURL()); |/t K-c6J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rSbQ}O4V  
httpConnection.setRequestProperty("User-Agent","NetFox"); >["Kd.ye  
Y& m<lnB  

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int responseCode=httpConnection.getResponseCode(); x;*VCs
 
if(responseCode>=400) h4hd<,  
{ ~(M*6b  
processErrorCode(responseCode); L% zuI& q  
return -2; //-2 represent access is error .GtINh
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} 6eOxF8  
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String sHeader; NrW[Q3E$  
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for(int i=1;;i++) br10ptEx  
{ pM,#wYL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J (=4  
//Utility.log(in.readLine()); ayN*fiV]  
sHeader=httpConnection.getHeaderFieldKey(i); 2pw>B%1WP)  
if(sHeader!=null) Aw5K3@Ltz  
{ QZz&1n  
if(sHeader.equals("Content-Length")) hg!x_Eq|  
{ 2Sv>C `FMU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5'),)  
break; p+!f(H  
} +I?Qg  
} E:%>0FE  
else t<8z08  
break; +)% ,G@-`  
} _%XbxP6rH  
} +~@7" |d  
catch(IOException e){e.printStackTrace ();} tYF$#Nor#k  
catch(Exception e){e.printStackTrace ();} K T%i,T  
}`?7\\6  
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Utility.log(nFileLength); #V,LNX)  
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return nFileLength; u87=q^$  
} q=J9LQ  
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@^BS#  
//保存下载信息（文件指针位置） 2J1B$.3'  
private void write_nPos()  `NTM%# w  
{ 3KB|NS  
try{ 4,o %e,z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `e4o1*  
output.writeInt(nStartPos.length); ZE{aS4c  
for(int i=0;i<nStartPos.length;i++) dVij <! Lu  
{ r{bg
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// output.writeLong(nPos); /vMQF+  
output.writeLong(fileSplitterFetch.nStartPos); jo]m12ps  
output.writeLong(fileSplitterFetch.nEndPos); )j$b
9ZBk  
} &IIJKn|_  
output.close(); D:+)uX}MOf  
} S5zpUF=  
catch(IOException e){e.printStackTrace ();} CD*f4I#d  
catch(Exception e){e.printStackTrace ();} tj`tLYOZ@-  
} ]:[)KZ~  
))8Emk^Q{  
vQ?MM&6  
//读取保存的下载信息（文件指针位置） h2im sjf  
private void read_nPos() +d|:s  
{ 3Pw%[q=g  
try{ };4pZceV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~5x4?2  
int nCount = input.readInt(); ~NTDG  
nStartPos = new long[nCount]; {Q}!NkF1  
nEndPos = new long[nCount]; "FD<^  
for(int i=0;i<nStartPos.length;i++) _Ac/ir[,:  
{ Krt$=:m|1  
nStartPos = input.readLong(); f>.`xC{  
nEndPos = input.readLong(); v)wY  
} FF5tPHB  
input.close(); 6:e}v'q{  
} nL "g23  
catch(IOException e){e.printStackTrace ();} kxt\{iy4  
catch(Exception e){e.printStackTrace ();} ]Om'naD  
} ~R
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private void processErrorCode(int nErrorCode) N` @W%  
{ =*@MQ  
System.err.println("Error Code : " + nErrorCode); $%N;d>[U,  
} 3sd{AkD^  
9Ba%=  
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//停止文件下载 [,.[gWA  
public void siteStop() a>-}\GXTA  
{ n23%[#,r  
bStop = true; ^K1~eb*K  
for(int i=0;i<nStartPos.length;i++) :HQ8M*o  
fileSplitterFetch.splitterStop(); C}dKbs^g|  
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} #"3[f@|e  
} T%
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//负责部分文件的抓取 +xoyKP!  
**FileSplitterFetch.java A52LH,  
*/ c+)36/; X  
package NetFox; kMfc"JXF  
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import java.io.*; o(v"?Y6  
import java.net.*; 4eDmLC"Y *  
=!I8vQ>  
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public class FileSplitterFetch extends Thread { (r#
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String sURL; //File URL LLXg  
long nStartPos; //File Snippet Start Position I{*.htt{  
long nEndPos; //File Snippet End Position tkm~KLWV&7  
int nThreadID; //Thread's ID +R{A'Yl[(  
boolean bDownOver = false; //Downing is over yH0yO*RZ  
boolean bStop = false; //Stop identical vu !j{%GO  
FileAccessI fileAccessI = null; //File Access interface XZUB*P}]D  
/h}wM6pg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {Oc?C:aI=  
{ T_5*iwI  
this.sURL = sURL; ~#IWM+I  
this.nStartPos = nStart; "Gi+zkVm  
this.nEndPos = nEnd; |g: '')>[  
nThreadID = id; X-*KQ+?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &"~,V6,q  
} .&* ({UM  
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public void run() p3,(*eZ  
{ n;S0fg  
while(nStartPos < nEndPos && !bStop) L:k@BCQM  
{ 7>W+Uq  
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try{ FEm1^X#]  
URL url = new URL(sURL); >h/)r6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h^[ppc{Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); <.?^LT  
String sProperty = "bytes="+nStartPos+"-"; z Et6  
httpConnection.setRequestProperty("RANGE",sProperty); F| ,Vw{  
Utility.log(sProperty); ;ZE<6;#3IP  
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InputStream input = httpConnection.getInputStream(); $@ T6g  
//logResponseHead(httpConnection); qw Kh,[]  
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byte[] b = new byte[1024]; ?=|)n%  
int nRead; fxtYo,;$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m\}\RnZu  
{ =oKPMmpCZ  
nStartPos += fileAccessI.write(b,0,nRead); Bcd0  
//if(nThreadID == 1) Hm8EYPrJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;k63RNT,M&  
} ] fwTi(4y  
6U,U[MWJ  
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Utility.log("Thread " + nThreadID + " is over!"); f4aD0.K.g|  
bDownOver = true; +"N<-  
//nPos = fileAccessI.write (b,0,nRead); =w;xaxjL  
} ,pGCgOG#}c  
catch(Exception e){e.printStackTrace ();} u1pYlu9IW  
} VW<"c 5|  
} NZw[.s>n  
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//打印回应的头信息 HpjIp.  
public void logResponseHead(HttpURLConnection con) DY+8m8!4H  
{ e) /u>I  
for(int i=1;;i++) !z4Hj{A_  
{ -c<1H)W  
String header=con.getHeaderFieldKey(i); rTH[?mkf4  
if(header!=null) ?XTg%U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |]2eGrGj4  
Utility.log(header+" : "+con.getHeaderField(header)); 3Oig/KZ  
else Yf2+@E  
break; |Z^c#R  
} )lngef /D_  
} WSpg(\Cs  
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public void splitterStop() Q+%m+ /Zq  
{ ~1wdAq`'a  
bStop = true; >FMT#x t  
} J?,!1V=  
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} NId~|&\  
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/* `$x#_-Hn  
**FileAccess.java o._#=7|(  
*//文件访问(定位，写) qeO6}A"^|  
package NetFox; %Cbc@=k  
import java.io.*; uK&wS#uY  
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public class FileAccessI implements Serializable{ |{|r?3  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :Ro" 0/d  
RandomAccessFile oSavedFile; F#37Qv  
long nPos; *mhw5Z=!  
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public FileAccessI() throws IOException 'r?HL;,q  
{ lt(-,md  
this("",0); kk\zZC <  
} 9
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public FileAccessI(String sName,long nPos) throws IOException Z_4H2HseL  
{ uRq#pYn
@  
oSavedFile = new RandomAccessFile(sName,"rw"); Er+3S@sfq,  
this.nPos = nPos; s?\9i6  
oSavedFile.seek(nPos); fOjt` ~ToI  
} d\<aJOi+-  
#/sE{jm  
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public synchronized int write(byte[] b,int nStart,int nLen) M0IqQM57N  
{ X|n[9h:%  
int n = -1; kFZu/HRI  
try{ >zx50e)  
oSavedFile.write(b,nStart,nLen); u.K'"-xt4K  
n = nLen; 'FA)LuAok  
} TboHP/  
catch(IOException e) eRqexqO!  
{ ,["|wqM  
e.printStackTrace (); d~1"{WPSn  
} 'N,NG$G2  
{4jSj0W  
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return n; %m\G'hY2  
} LVcy.kU@]  
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} k49n9EX  
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/* -bb7Y  
**SiteInfoBean.java @_:?N(%(  
*/ v&/-&(+  
package NetFox; zSv
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public class SiteInfoBean { Fu$Gl$qV?%  
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private String sSiteURL; //Site's URL ump:dL5{  
private String sFilePath; //Saved File's Path f7AJSHe  
private String sFileName; //Saved File's Name R#^pNJN  
private int nSplitter; //Count of Splited Downloading File $A0]v!P~i-  
yT9RNo/w  
GN"LU
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public SiteInfoBean() GQAg ex)D  
{//nSplitter的缺省值为5 FHPZQC8  
//default value of nSplitter is 5 M]zNW{Xt  
this("","","",5); qf&
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} 8[P6c;\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~5qZs"ks  
{ f6A['<%o  
sSiteURL= sURL; F"?
*@
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sFilePath = sPath; ?BZ`mrH^  
sFileName = sName; X1QZEl  
this.nSplitter = nSpiltter; k#G7`dJl  
48*pKbbM4  
QL!+.y%  
} ;xC~{O  
HQj4h]O#
 
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public String getSSiteURL() +uXnFf d^  
{ ~
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return sSiteURL; B9Tztg  
} \B+SzW  
`fh_8%m]*  
gM[ J'DMW  
public void setSSiteURL(String value) _@?Jx/`;bk  
{ 03\8e?$  
sSiteURL = value; 5Kxk9{\8  
} rSCX$ @@F  
`%:(IGxz  
Yzx0[_'u  
public String getSFilePath() >V=@[B(0  
{ ^u&Khc~ y  
return sFilePath; W
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} jmVy4* P_  
\(t>(4s_~  
iz5wUyeg  
public void setSFilePath(String value) W%QtJB1)  
{ j@\/]oL^We  
sFilePath = value; '
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} Eu~wbU"%  
JU+'UK630  
KftM4SFbK  
public String getSFileName() Pu*UZcXY  
{ |W];v@b\y  
return sFileName; eV}Tx;1|}  
} LMj'?SuH  
nECf2>Yp v  
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public void setSFileName(String value) \`# 0,pLr  
{ HBGA lZ  
sFileName = value; %+J*oFwQu  
} S*@0%|Q4r  
U MIZ:*j  
T<
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public int getNSplitter() 7OHw/-j\  
{ V2skr_1  
return nSplitter; [)c|o
h%  
} 84cH|j`w  
4u7>NQUDu  
RL8wSK  
public void setNSplitter(int nCount) ?saVk7Z[|5  
{ Ka2tr]+s  
nSplitter = nCount; SXF_)1QO\W  
} aBLb i  
} L#bQ`t  
ay[*b_f  
M&-/&>n!  
/* "A3xX&9-q  
**Utility.java l_EI7mJ  
*/ A2S9h,t  
package NetFox; S*:w\nXP~  
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public class Utility { Rj=Om  
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public Utility() 5nb6k,+E  
{ 6[7k}9`alz  
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F'*4:WD7  
} ,Yz+?SmSZ&  
=1Jo-!{{  
//线程睡眠 VHNiTp  
public static void sleep(int nSecond) "V2$g  
{ C>ZeG Vq  
try{ pdqh'+5  
Thread.sleep(nSecond); mr.DP~O:9p  
} rNp#5[e  
catch(Exception e) Xpwom'  
{ 5)6%D  
e.printStackTrace (); EV$n>.  
} gu&oCT  
} ij5YV3  
OSk9Eb4ld  
//日志 L\DaZ(Y  
public static void log(String sMsg) gp2)35  
{ {*Pp^r  
System.err.println(sMsg); ![%,pip2/&  
} m"]ys#  
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t68RWzqiG[  
public static void log(int sMsg) &.B6P|N'  
{ IrC=9%pd$R  
System.err.println(sMsg); L;`t%1  
} 5Bo)j_Qo  
} Z]d]RL&r  
9f`Pi:*+/  
q#Vf2U55m  
/* O!tD1^O!1}  
**TestMethod.java :_ox8xS4  
*/ lsCh K  
package NetFox; gZv<_0N  
*Cw2h  
SGm?"esEt  
public class TestMethod { 9_{!nQC.g  
[DwB7l)O(  
g(k|"g`*  
public TestMethod() RUKSGj_NJ  
{ ///xx/weblogic60b2_win.exe ^EOjq  
try{ -&}E:zoe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); OFv} jT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _!zY(9%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3FN? CN] O  
fileFetch.start(); 3LREue7Gr  
} vKf=t&gqr  
catch(Exception e){e.printStackTrace ();} g=Di2j{A  
-f=hL7NW  
/jD'o>  
} KG$2u:n  
9j`-fs
@:  
|{T2|iJI  
public static void main(String[] args) }__+[-  
{ A$cbH.  
new TestMethod(); h;->i]  
} -yeT$P&|  
} "Cb<~Dy  
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