http断点续传简单实现（java)

/* "NEKz  
**SiteFileFetch.java EronNtu8i  
*/ X=Y(,ZR(&  
package NetFox; o8A8fHl  
import java.io.*; ::GW  
import java.net.*; -IDhK}C&T  
B'O1dRj&6  
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public class SiteFileFetch extends Thread { 7)>L#(N  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8{%&P%vf  
long[] nStartPos; //开始位置 E+ XR[p  
long[] nEndPos; //结束位置 7bVKH[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u^
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long nFileLength; //文件长度 :.{d,)G  
boolean bFirst = true; //是否第一次取文件 Du-Q~I6  
boolean bStop = false; //停止标志 ]|IeE!6  
File tmpFile; //文件下载的临时信息 hr&UD|E=  
DataOutputStream output; //输出到文件的输出流 "cOBEhn%l  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ulEtZ#O{_  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3+C;zDKa  
{ VVuNU"-  
siteInfoBean = bean; +,i_G?eX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QD-Bt=S7l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {q&`B  
if(tmpFile.exists ()) r'|ei,  
{ ,>kXn1 ,  
bFirst = false; ]g%HU%R-m  
read_nPos(); >*|Eyv_  
} *Hv d  
else DU5rB\!.~  
{ ^|!\IzDp  
nStartPos = new long[bean.getNSplitter()]; _?$')P|  
nEndPos = new long[bean.getNSplitter()]; z,!A4ws  
} t`Xx\  
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} sAK&^g  
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public void run() QdD@[  
{ nAsc^Yh  
//获得文件长度 Fvnf;']q  
//分割文件 |^w&dj\,  
//实例FileSplitterFetch ,6A/| K-  
//启动FileSplitterFetch线程 '1G0YfG}n  
//等待子线程返回 hig t(u  
try{ 27F:-C~.9  
if(bFirst) J3r':I}\  
{ 6Tq2WZ}<'  
nFileLength = getFileSize(); Pi%-bD/w  
if(nFileLength == -1) V Kc`mE  
{ k?Zcv*[)D+  
System.err.println("File Length is not known!"); l`:-B'WM  
} 1P BnGQYM  
else if(nFileLength == -2) F=UW[zy/[  
{ COH.`Tv{*  
System.err.println("File is not access!"); 09iD| $~  
} [eDRghK  
else dVJ9cJ9^  
{ Lk)T
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for(int i=0;i<nStartPos.length;i++) 1"1ElH  
{ 1aUu:#c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #yCnM]cEn  
} |g\CS4$  
for(int i=0;i<nEndPos.length-1;i++) |c2;`T#`o  
{ V* ,u;*  
nEndPos = nStartPos[i+1]; 6fT^t!<i  
} I(9+F  
nEndPos[nEndPos.length-1] = nFileLength; ^w*vux|F  
} s21)*d  
} 2%pe.stQ  
#vR5a}BAk  
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//启动子线程 A.!3{pAb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?CpM.{{s  
for(int i=0;i<nStartPos.length;i++) NL"w#kTc()  
{ `_{,4oi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ggHl{cl)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !U1V('   
nStartPos,nEndPos,i); J=#9eW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^$8WV&5q>  
fileSplitterFetch.start(); HDhG1B"NL  
} EOGz;:b&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y8|}bd<Sr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iz`ys.Fu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Lo9 \[4FP  
nEndPos = " + nFileLength); j2#B l  
// fileSplitterFetch[nPos.length-1].start(); bWB&8&p  
7{[i)  
.R@euIva
 
//等待子线程结束 FJB /tg  
//int count = 0; ~HBx5Cpi  
//是否结束while循环 )U2%kmt  
boolean breakWhile = false; Z1DF)  
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9:Z|Z?>?  
while(!bStop) aS+i`A:a  
{ *jy"g64j  
write_nPos(); j)jt&Gg'  
Utility.sleep(500); ,\PTn7_  
breakWhile = true; K$ |!IXs  
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for(int i=0;i<nStartPos.length;i++) y)`q% J&  
{ pf_`{2.\uO  
if(!fileSplitterFetch.bDownOver) \j vS`+  
{ XP@&I[J3sI  
breakWhile = false; i]zTY\gw8M  
break; uU8L93  
} p;vrPS  
} c=IjR3F  
if(breakWhile) liH1r1M  
break; p/jAr+XM  
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//count++; /.m}y$@GV  
//if(count>4)
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// siteStop(); StMvz~  
} YZ5[#E@l  
6IL-S%EGK1  

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System.err.println("文件下载结束！"); 'i8?]` T  
} 4"V6k4i5  
catch(Exception e){e.printStackTrace ();} J2$=H1-  
} I,?!NzB  
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//获得文件长度 O}[){*GG=  
public long getFileSize() _jk+$`[9PL  
{ ~*G}+Ur$2  
int nFileLength = -1; vg[zRWh8  
try{ O u{|o0  
URL url = new URL(siteInfoBean.getSSiteURL()); j(Tk6S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); toC|vn&P  
httpConnection.setRequestProperty("User-Agent","NetFox"); $b"Ex>  
8"x\kSMb  
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int responseCode=httpConnection.getResponseCode(); H~ =;yy  
if(responseCode>=400) 4' <y  
{ VD2o#.7*eu  
processErrorCode(responseCode); RS Vt

 
return -2; //-2 represent access is error uulzJb
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} O>arCr=H  
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S >\\n^SbT  
String sHeader; a(+u"Kr z  
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for(int i=1;;i++) _v=zFpR  
{ \1#!%I=.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &d[%  
//Utility.log(in.readLine()); 3+:
uV  
sHeader=httpConnection.getHeaderFieldKey(i); 3_c4+u"6  
if(sHeader!=null) [[8h*[:  
{ ig:z[k?  
if(sHeader.equals("Content-Length")) \&%y4=y<sE  
{ x!9bvQT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ut9R]01:  
break; ' ui`EL%  
} &ETPYf%#  
} v1Jg8L=  
else SCD;(I~4  
break; C~VyM1inD  
} 6
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} ZY> u4v.  
catch(IOException e){e.printStackTrace ();} ;F>I+l_X  
catch(Exception e){e.printStackTrace ();}  2dBjc{  
)N]%cO(^  
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Utility.log(nFileLength); [r=U-  
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return nFileLength; M%FKg/  
} Zq"wq[GC
N  
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//保存下载信息（文件指针位置） xT3l>9i  
private void write_nPos() Dlu]4n[LB  
{ 7#iT
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try{ C)qP9uW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eqWb>$  
output.writeInt(nStartPos.length); |:d:uj/  
for(int i=0;i<nStartPos.length;i++) ` oXL  
{ jh.e&6  
// output.writeLong(nPos); >oc&hT  
output.writeLong(fileSplitterFetch.nStartPos); v`u>;S_  
output.writeLong(fileSplitterFetch.nEndPos); 7)v`l1  
} Zl`sY5{1  
output.close(); Jl^THoEL  
} JB\BP$ap  
catch(IOException e){e.printStackTrace ();} FuZLE%gP  
catch(Exception e){e.printStackTrace ();} ( 0Z3Ksfj1  
} G@]|/kN1y  
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!  
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//读取保存的下载信息（文件指针位置） t%>x}b"2T  
private void read_nPos() U})Z4>[bvt  
{ o[CjRQY]P  
try{ I~I$/j]e`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O\qY?)  
int nCount = input.readInt(); <\5Y~!)  
nStartPos = new long[nCount]; vH9Gf  
nEndPos = new long[nCount]; t>>\U X  
for(int i=0;i<nStartPos.length;i++) wKs-<b%;  
{ Yo#F;s7  
nStartPos = input.readLong(); (Qys`D   
nEndPos = input.readLong(); }X*.Vv A  
} fTc,"{  
input.close(); H)&pay  
} Z8Il3b*)  
catch(IOException e){e.printStackTrace ();} T~'9p`IW  
catch(Exception e){e.printStackTrace ();} lEv<n6:_  
} wC[Bh^]  
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private void processErrorCode(int nErrorCode) BHBMMjY5  
{ *]_GFixi  
System.err.println("Error Code : " + nErrorCode); 4FgY!k  
} E$84c+  
/!Kl  
7Y(ySW  
//停止文件下载 L]HYk}oD.  
public void siteStop() tqo!WuZAj  
{ kaj6C_k|  
bStop = true; ?*8HZ1m#  
for(int i=0;i<nStartPos.length;i++) 5Pl~du  
fileSplitterFetch.splitterStop(); O6pL )6d  
n
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F DCHB~D  
} c;e2= A  
} Bswd20(w  
//负责部分文件的抓取 J]|lCwF  
**FileSplitterFetch.java \dag~b<  
*/ <\cH9D`dE  
package NetFox; Z"fnjH
 
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import java.io.*; s GP}>w-JZ  
import java.net.*; 1y5$  
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public class FileSplitterFetch extends Thread { /8` S}g+  
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String sURL; //File URL e r;3TG~  
long nStartPos; //File Snippet Start Position h}U\2$5  
long nEndPos; //File Snippet End Position xBC:%kG~#  
int nThreadID; //Thread's ID #}A >B  
boolean bDownOver = false; //Downing is over ep<2u x  
boolean bStop = false; //Stop identical x@]pUA1  
FileAccessI fileAccessI = null; //File Access interface Ng} AEAFp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AT{ewb  
{ g{cHh(S  
this.sURL = sURL; cKX6pG  
this.nStartPos = nStart; 1Bz'$u;  
this.nEndPos = nEnd; FT* o;&_QS  
nThreadID = id; F W# S.<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :oH"  
} GBZx@B[TY  
=R^V[zTn_  
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public void run() 0F<O \  
{ w^&TG3m1~  
while(nStartPos < nEndPos && !bStop) 4{\h53j$  
{ ?)cNe:KY  
$[Fh|%\  
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try{ F=hfbCF5x  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o"x&F  
httpConnection.setRequestProperty("User-Agent","NetFox"); [D H@>:"dd  
String sProperty = "bytes="+nStartPos+"-"; {O,Cc$_  
httpConnection.setRequestProperty("RANGE",sProperty); ]AGJPuX  
Utility.log(sProperty); N+?kFob  
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InputStream input = httpConnection.getInputStream(); +*Cg2`  
//logResponseHead(httpConnection); 8<t?o'9I  
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eb)S<%R/  
byte[] b = new byte[1024]; QH%{r4  
int nRead; OwQ 9y<v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3 SQ_9{  
{ OX?9 3AlG  
nStartPos += fileAccessI.write(b,0,nRead); >29eu^~nh  
//if(nThreadID == 1) Z<|caT]Q(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P$)9osr  
} -9U'yL90B  
|Js96>B:  
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Utility.log("Thread " + nThreadID + " is over!"); (iK0T.  
bDownOver = true; ,FJ9C3  
//nPos = fileAccessI.write (b,0,nRead); X./4at`  
} >:s.`jV<  
catch(Exception e){e.printStackTrace ();} VYhZ0;' '  
} flLC\  
} J680|\ER  
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//打印回应的头信息 UJ)\E ^Hp  
public void logResponseHead(HttpURLConnection con) t9PS5O ;  
{ %+G/oF|  
for(int i=1;;i++) hSD)|  
{  { Lt\4h  
String header=con.getHeaderFieldKey(i); -{ZTp8P>  
if(header!=null) AdB5D_ Ir  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .l*]W!L]  
Utility.log(header+" : "+con.getHeaderField(header)); j~"X`:=  
else f
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break; H#G~b""mY  
} 11 .RG *  
} HqU"iY>b  
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}_M.-Xm  
public void splitterStop() A{;b^IK  
{ 3u7E?*{sH  
bStop = true; ?S0VtHQ  
} ;2}0Hr'|  
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} tGD$cBE  
;'pEzz?k"  
~?6V-m{>#  
/* tZ=BK:39\  
**FileAccess.java 0sq/_S  
*//文件访问(定位，写) &^4W+I{H  
package NetFox; /,= wP)  
import java.io.*; sj`9O-?49  
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public class FileAccessI implements Serializable{ KL0u:I(lWU  
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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 m5zP|s1`['  
RandomAccessFile oSavedFile; 89@89-_mC  
long nPos; 'oEFN
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public FileAccessI() throws IOException ~@bCSOIy  
{ ?i(Tc
!  
this("",0); pp#Kb 2*  
} 42Vy#t/HC  
*s?&)][  
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public FileAccessI(String sName,long nPos) throws IOException : Ot\l  
{ h.4;-&
 
oSavedFile = new RandomAccessFile(sName,"rw"); oRy?Dx+H  
this.nPos = nPos; & HphE2 h  
oSavedFile.seek(nPos); dlK#V)  
} %o#D"  
$}OU~d1q  
0c7&J?"wE  
public synchronized int write(byte[] b,int nStart,int nLen) &N*S   
{ 0wZLkU_(  
int n = -1; DZ ~|yH  
try{ 5HL JkOV5  
oSavedFile.write(b,nStart,nLen); h:#  
n = nLen; .rG Rdb  
} Ua V9T:)x  
catch(IOException e) Nf0b?jn-  
{ o|l)oc6{  
e.printStackTrace (); n1uJQt  
} v2EM| Q xp  
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return n; V>A@Sw  
} zmf5!77  
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} N iNZh;  
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/* ?8! 4!P%n  
**SiteInfoBean.java '/;#{("  
*/ *-_` xe  
package NetFox; ):LJ {.0R  
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public class SiteInfoBean { ?*,N ?s(U  
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private String sSiteURL; //Site's URL wxo(  
private String sFilePath; //Saved File's Path l%fnGe` _  
private String sFileName; //Saved File's Name s.C-II?e  
private int nSplitter; //Count of Splited Downloading File !S%XIq}FX  
_4zlEo-.gU  
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public SiteInfoBean() }[D~#Z!k  
{//nSplitter的缺省值为5 3$l'>v+5{  
//default value of nSplitter is 5 / )5B  
this("","","",5); >0@X^o  
} "H%TOk7l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z~o%U&DO}  
{ _=q)lt-UY  
sSiteURL= sURL; }#EiL !Pv  
sFilePath = sPath; c4L5"_#`x-  
sFileName = sName; X"iy.@7  
this.nSplitter = nSpiltter; X-oou'4<  
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} X@af[J[cQ  
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public String getSSiteURL() kfm8F8sxl  
{ L-@j9hU{  
return sSiteURL; 6n%^ U2H/-  
} "M_X9n_  
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public void setSSiteURL(String value) oc\rQ?  
{ }4_izKS  
sSiteURL = value; 7i334iQZ  
} 4y 582u6^  
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public String getSFilePath() nF A7@hsm  
{ \e'>$8%T  
return sFilePath; SAThY$)6  
} f} }Bb8  
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public void setSFilePath(String value) 8"8sI  
{ x*BfRj  
sFilePath = value; 1K^/@^  
} y<)Lr}gP  
JkQ4'$:  
! ~&X1,l1*  
public String getSFileName() IO^O9IEx,  
{ JO+ hD4L  
return sFileName; b LL!iz?  
} {*jkx,|  
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public void setSFileName(String value) [u)^QgP  
{ -k$rkKHZ(  
sFileName = value; H[]j
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} ]C)PZZI='  
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B Sb!{|]  
public int getNSplitter() O_F<VV*MFQ  
{ ?>RJ8\Sj  
return nSplitter; wAkoX  
} TKRu^KH9  
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public void setNSplitter(int nCount) 2!]':(8mR  
{ !WVF{L,/I  
nSplitter = nCount; q3scz  
} pN*>A^  
} AU-/-h=Mr  
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/* \zj8| +  
**Utility.java qMI%=@=  
*/ J#:%| F%  
package NetFox; x:sTE u@  
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|!57Z4X  
public class Utility { !8l4H
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public Utility() 4!/{CGP  
{ A`X$jpAn&  
]MUuz'<
 
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} 3ufUB^@4v  
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//线程睡眠 M5Pvc  
public static void sleep(int nSecond) X*%KR4`
 
{ jw(v08u >  
try{ Rfa1v*(  
Thread.sleep(nSecond); S1&6P)X.Za  
} dLQ!hKD~  
catch(Exception e) $[FO(w@f  
{ J tYnBg?[E  
e.printStackTrace (); #@y4/JS&2  
} ^
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} p(U'c}@2
 
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//日志 z4{|?0=C  
public static void log(String sMsg) Eer rIV  
{ (MNbABZQ  
System.err.println(sMsg);
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} 7*@qd&  
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public static void log(int sMsg) QabF(}61  
{ K-p1v!IC  
System.err.println(sMsg); bS* "C,b~s  
} %G\rL.H|  
} zbi[r  
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->K*r\T  
/* 4V<s"  
**TestMethod.java `+]4C+w  
*/ rC/m}`b  
package NetFox; FeSe^^dW  
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public class TestMethod { g<}K^)x  
uWi+F)GS^K  
:[\}Hn=  
public TestMethod() c5]^jUB6  
{ ///xx/weblogic60b2_win.exe OU0\xx1/  
try{ aSKI%<?xN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mNcTO0p&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Jqjb@'i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j<wg>O:s%r  
fileFetch.start(); ` [@ F3x  
} MH!'g7iK8  
catch(Exception e){e.printStackTrace ();} d;;]+%  
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} /lAt&0  
r+v*(Tu  
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public static void main(String[] args) ]hL 1qS  
{ "'II~/9  
new TestMethod(); KQQR"[z&V  
} 1 ljgq]($  
} vpOzF>O  
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