http断点续传简单实现（java)

/* #ZIV>(Q\H  
**SiteFileFetch.java j=)%
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*/ kRgyvA,*;  
package NetFox; {sy#&m(el  
import java.io.*; g S;p::  
import java.net.*; u pf7:gk +  
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public class SiteFileFetch extends Thread { ^sq3@*hCw  
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SiteInfoBean siteInfoBean = null; //文件信息Bean IPcAE!h6zN  
long[] nStartPos; //开始位置 k6~k  
long[] nEndPos; //结束位置 @ -JD`2z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q<}5KY  
long nFileLength; //文件长度 ^Y xqJy  
boolean bFirst = true; //是否第一次取文件 ?Z]}G  
boolean bStop = false; //停止标志 \1RQ),5 %]  
File tmpFile; //文件下载的临时信息 cW),Y|8  
DataOutputStream output; //输出到文件的输出流  !+IxPn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y[;Pl$  
public SiteFileFetch(SiteInfoBean bean) throws IOException )%C482GO-  
{ pM\)f  
siteInfoBean = bean; B4&@PX"'>,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r{kV*^\E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tqrvcnQr^  
if(tmpFile.exists ()) T}P|uP  
{ /'G'GQrr  
bFirst = false; N7Z&_$Bx  
read_nPos(); [*?P2.bf  
} #l-,2C~  
else ']f]:X;6w  
{ T~%5^+[h  
nStartPos = new long[bean.getNSplitter()]; 7F3Hkvd[k  
nEndPos = new long[bean.getNSplitter()]; ]k{cPK  
} ZzI^*Nyg  
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} ekP=/;T#S  
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public void run() " %|CD"
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{ 8ne'x!1 D  
//获得文件长度 _Ux>BJmP  
//分割文件 AUoi$DF(@  
//实例FileSplitterFetch M.d{:&@`%  
//启动FileSplitterFetch线程 622mNY  
//等待子线程返回 ms ;RJT2O'  
try{ 3Du&KZ  
if(bFirst) u!nt0hS  
{ "SyyOD )WA  
nFileLength = getFileSize(); nH% /  
if(nFileLength == -1) y~1UU3k5  
{ Ft`#]=IS  
System.err.println("File Length is not known!"); pWps-e  
} e7/J:n$  
else if(nFileLength == -2) GG;M/}E9  
{ .6$ST Ksr  
System.err.println("File is not access!"); 9A3Q&@,  
} &)fPz-s  
else X~G"TT$)  
{ x`%;Q@G  
for(int i=0;i<nStartPos.length;i++) tq@<8?  
{ DfV_0
8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wGISb\rr  
} ffm19B=  
for(int i=0;i<nEndPos.length-1;i++) 3=dGz^Zdv:  
{ RPaB4>  
nEndPos = nStartPos[i+1]; m^T$H_*;  
} 6Om-[^  
nEndPos[nEndPos.length-1] = nFileLength; Ko''G5+  
} FPFt3XL  
} 9z_Gf]J~  
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//启动子线程 A1%V<im@Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kf-ZE$S4  
for(int i=0;i<nStartPos.length;i++) N4fuV?E`  
{ ENJ]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wqE ]o= k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P). @o.xl  
nStartPos,nEndPos,i); )CdglPK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O:lD>A4{  
fileSplitterFetch.start(); f 21w`Uk48  
} 1 ,D2][  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [(ty{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Di-"y,[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8CA4gnh  
nEndPos = " + nFileLength); #wM0p:<  
// fileSplitterFetch[nPos.length-1].start(); .D4D!!  
$!obpZ~}  
v l{hE~  
//等待子线程结束 o{UwUMw5`  
//int count = 0; 3O#7OL68v  
//是否结束while循环 4sZ^:h,1  
boolean breakWhile = false; >454Yir0Mk  
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while(!bStop) <hy>NM@$  
{ zG& N5t96X  
write_nPos(); 8
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Utility.sleep(500); sSD(mO<(  
breakWhile = true; IUc!nxF#  
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for(int i=0;i<nStartPos.length;i++) @4$F%[g h  
{ G =< KAJ  
if(!fileSplitterFetch.bDownOver) SC|cCK hqi  
{ M9f*7{c  
breakWhile = false; u%}vTCg*p  
break; )[nzmL*w  
} t'9E~_!C  
}
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if(breakWhile) Ujj2A^  
break; tanuP@O  
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9sE>K)  
//count++; 7*`ldao~  
//if(count>4) O=mGL  
// siteStop(); I}k!i+Yl  
} B[$KnQM9Y  
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})!n1kt  
System.err.println("文件下载结束！"); ARU
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} e2B~j3-?z  
catch(Exception e){e.printStackTrace ();} j./bVmd.  
} >Q+EqT  
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k+i}U9c"  
//获得文件长度 NqF-[G<  
public long getFileSize() mup3ua]!  
{ h{PLyWH  
int nFileLength = -1; 4El{2cfA  
try{ x!YfZ*  
URL url = new URL(siteInfoBean.getSSiteURL()); **s:H'Mw_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^?J:eB!  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1km=9[;w'  
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int responseCode=httpConnection.getResponseCode(); !J2Lp  
if(responseCode>=400) slQKkx \Dn  
{ Kw?,A   
processErrorCode(responseCode); W%h<@@c4,  
return -2; //-2 represent access is error E-"Jgq\aC  
} MESQAsx%  
}W|CIgF*  
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String sHeader; 1m![;Pg3  
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for(int i=1;;i++) {UPIdQ'g  
{ 5 !NPqka}.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^NnZYr.  
//Utility.log(in.readLine()); KR522YW  
sHeader=httpConnection.getHeaderFieldKey(i); uNRGbDMA=  
if(sHeader!=null) 3(PU=  
{ qmL!"ZRLF  
if(sHeader.equals("Content-Length")) ^ul`b  
{ 5SKu\H\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S3oU7*OZ  
break; 2qn~A0r  
} _`D_0v(X  
} KM\`,1?x92  
else f%|g7[  
break; ~;`i&s  
} BM3)`40[]  
} Jhut>8  
catch(IOException e){e.printStackTrace ();} XM=`(e o  
catch(Exception e){e.printStackTrace ();} nwkhGQ  
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Utility.log(nFileLength); 6U""TR!   
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return nFileLength; T[;{AXLeI  
} $==hr^H  
hi ]+D= S  
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//保存下载信息（文件指针位置） };KmMpBn  
private void write_nPos() S%T1na^x  
{ 4a646jg)  
try{ [%h^qJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }5S2v+zE  
output.writeInt(nStartPos.length); 4Fz^[L}[  
for(int i=0;i<nStartPos.length;i++) )O+9v}2  
{ 5GRN1Aov<  
// output.writeLong(nPos); nC*/?y*9  
output.writeLong(fileSplitterFetch.nStartPos); Ugs<WVp$  
output.writeLong(fileSplitterFetch.nEndPos); @'U4-x  
} TZ*ib~  
output.close(); P.fgt>v]  
} f~U|flL^  
catch(IOException e){e.printStackTrace ();} ~O|0.)71]  
catch(Exception e){e.printStackTrace ();} gT+/CVj R  
} +_ G'FD  
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//读取保存的下载信息（文件指针位置） woR)E0'qx  
private void read_nPos() 4%]{46YnK  
{ jBB<{VV|  
try{ ~_oTEXT^O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }Jtaq[y\r  
int nCount = input.readInt(); `
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nStartPos = new long[nCount]; U$J]^-AS  
nEndPos = new long[nCount]; |zUDu\MZ{  
for(int i=0;i<nStartPos.length;i++) xFvSQ`sp  
{ |Y99s)2&N  
nStartPos = input.readLong();  v EX <9  
nEndPos = input.readLong(); VEpQT Qp  
} 6D+k[oHZm  
input.close(); # K-Q/*  
} r94BEC 2  
catch(IOException e){e.printStackTrace ();} /2U.,vw  
catch(Exception e){e.printStackTrace ();} !eO?75/  
}  m$cM+  
}@#eD
 
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private void processErrorCode(int nErrorCode) >/n/n{{  
{ w5|"cD#8A  
System.err.println("Error Code : " + nErrorCode); vTP_vsdeG  
} )a6i8b3  
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//停止文件下载 kjmF-\  
public void siteStop() m|y]j4  
{ *X>rvAd3  
bStop = true; [v&_MQ  
for(int i=0;i<nStartPos.length;i++) *%8us~w5/  
fileSplitterFetch.splitterStop(); iVl"H@m
/  
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} !hc7i=V
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} - Z|1@s&  
//负责部分文件的抓取 fXqe7[  
**FileSplitterFetch.java 4 I~,B[|  
*/ LRI_s>7  
package NetFox; yw
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import java.io.*; OGVhb>LO1  
import java.net.*; T]my
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public class FileSplitterFetch extends Thread { /U`"|3  
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String sURL; //File URL ;F:(5GBi  
long nStartPos; //File Snippet Start Position y>o#Hq&qM  
long nEndPos; //File Snippet End Position *oPSkEA{  
int nThreadID; //Thread's ID eu4x{NmQ  
boolean bDownOver = false; //Downing is over hN}X11  
boolean bStop = false; //Stop identical vrbS-Z<S9  
FileAccessI fileAccessI = null; //File Access interface wx1uduT)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9}\T?6?8pX  
{ 6lhVwgy3A  
this.sURL = sURL; [DE8s[i-  
this.nStartPos = nStart; +:t1PV;l  
this.nEndPos = nEnd; hb_Ia]b  
nThreadID = id; RWoiV10  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x O)nS _I  
} 7}#vANm  
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public void run() eMF%!qUr  
{ `b2I)xC#  
while(nStartPos < nEndPos && !bStop) ALG #)$|  
{ (I+-wki"e  
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try{ =:2V4H(F  
URL url = new URL(sURL); 3)xV-Y9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -{w&ya4X  
httpConnection.setRequestProperty("User-Agent","NetFox"); k-89(  
String sProperty = "bytes="+nStartPos+"-"; Uarb [4OZ  
httpConnection.setRequestProperty("RANGE",sProperty); WFB2Ub7  
Utility.log(sProperty); *0iP*j/]  
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InputStream input = httpConnection.getInputStream(); $""[( d?0  
//logResponseHead(httpConnection); 7!%cKZCY  
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byte[] b = new byte[1024]; A ssf f;  
int nRead; |hpm|eZG"h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NBeGmC|  
{ o1Xk\R{  
nStartPos += fileAccessI.write(b,0,nRead); m$o|s1t  
//if(nThreadID == 1) hsl8@=_ B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ 9k^Hd[L$  
} W$3p,VTMmB  
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6^zv:C%  
Utility.log("Thread " + nThreadID + " is over!"); LJiMtqg  
bDownOver = true; )O}x&@
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//nPos = fileAccessI.write (b,0,nRead); Gzs x0%`)  
} '`RCNk5l  
catch(Exception e){e.printStackTrace ();} E`X+fJx  
} EfyF]cYL  
} dRu@5 :BP  
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//打印回应的头信息 "#9WF}  
public void logResponseHead(HttpURLConnection con) WOwIJrP  
{ lfGiw^  
for(int i=1;;i++) 3!d|K%J  
{ uM\~*@
  
String header=con.getHeaderFieldKey(i); x=H*"L=  
if(header!=null) c)lK{DC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p#?1l/f"  
Utility.log(header+" : "+con.getHeaderField(header)); Zj},VB*T  
else X{ Nif G  
break; 7' 6m;b~F  
} D~1nh%x_  
} MLR3A s  
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public void splitterStop() $<yb~z7J  
{ auO^v;s  
bStop = true; G,XFS8{%  
} 1 t#Tp$  
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}
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/* BBp
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**FileAccess.java dJ|]W|q<  
*//文件访问(定位，写) wRuJein#  
package NetFox; vI+PL(T@  
import java.io.*; 0nl)0|?Az  
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public class FileAccessI implements Serializable{ b'ew Od=  
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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 C ]#R7G  
RandomAccessFile oSavedFile; nmgW>U0jZh  
long nPos; YZoH{p9f  
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public FileAccessI() throws IOException doe[f_\  
{ bg$e80  
this("",0); ^&,{  
} XjX<?W  
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public FileAccessI(String sName,long nPos) throws IOException uxR_(~8  
{ e0hT  
oSavedFile = new RandomAccessFile(sName,"rw"); mG2}JWA  
this.nPos = nPos; +)V6"XY-(  
oSavedFile.seek(nPos); 3w0m:~KS6V  
} G q:7d]c~T  
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public synchronized int write(byte[] b,int nStart,int nLen) (C. 1'<]  
{ #cApk  
int n = -1; *{tJ3<t(1  
try{ K|s+5>]W/[  
oSavedFile.write(b,nStart,nLen); lxxK6;r~>  
n = nLen; 'Oq}BVR&  
} )JZfC&,  
catch(IOException e) 
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{ fCTjTlh  
e.printStackTrace (); D}_\oE/n  
} bhg"<I  
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return n; +C+3DwN  
} "#p)Z{v"!  
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} d$>1 2>>  
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/* r_o2d8  
**SiteInfoBean.java {^N=hI  
*/ GHoPv-#  
package NetFox; lk+)-J-lj'  
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public class SiteInfoBean { , X|oCD  
3"<{YEj8U  
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private String sSiteURL; //Site's URL LtNG<n)_BH  
private String sFilePath; //Saved File's Path ^91k@MC  
private String sFileName; //Saved File's Name L6',s4  
private int nSplitter; //Count of Splited Downloading File 1*=[% d7  
Q}1PPi,  
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public SiteInfoBean() <;acWT?(  
{//nSplitter的缺省值为5 2Gx&ECa,  
//default value of nSplitter is 5 WLizgVM  
this("","","",5); 4S9AXE6  
} ` a@NYi6  
6v.*%E*P  
{9)LHX7dN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B\4SB  
{ @jjp\~  
sSiteURL= sURL; wCkkfTO  
sFilePath = sPath; &yYK%~}t[  
sFileName = sName; id*UTY Tg  
this.nSplitter = nSpiltter; )+ S"`  
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} IoA"e@~t  
) I@gy  
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public String getSSiteURL() !5[?n3  
{ E|ZY2&J`4  
return sSiteURL; eyy&JjVs  
} gBrI
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public void setSSiteURL(String value) (z"Cwa@e  
{ >yT:eG  
sSiteURL = value; .'SM|r$  
} {U&Mo97rzX  
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N>@AsI  
public String getSFilePath() F-2HE><+  
{ Oa*/jZjr  
return sFilePath; KaO8rwzDN  
} zQ7SiRt7*  
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public void setSFilePath(String value) Inr ~9hz  
{ v6iV#yz3(  
sFilePath = value; D<nTo&m_  
} >j\zj] -"  
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public String getSFileName() 0
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{ d~YDg{H  
return sFileName; Kf(% aDYq  
} )M}bc1 _  
` R^[s56wp  
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public void setSFileName(String value) B<6*Ktc  
{ KJSN)yn\  
sFileName = value; As78yfK  
} pcL02W|J  
G!%1<SLi.  
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public int getNSplitter() 9;q@;)'5  
{ u\>Ed
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return nSplitter; wGw}a[
a  
} 011 _(v  
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public void setNSplitter(int nCount) g_.BJ>Uv  
{ hC~lH eH  
nSplitter = nCount; {Uu7@1@n  
} tpA7"JD  
} u5%.T0 P  
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1jQz%^~  
/* X%39
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**Utility.java Hn:%(Rg=aW  
*/ ]xV7)/b5G  
package NetFox; ,7tN&R_  
RYmk6w!w  
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public class Utility { B*,9{g0m/  
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public Utility() ^D/*Hp _  
{ 5GC{)#4  
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} 82>zu}  
~pwp B2
c  
//线程睡眠 yS lN|8d  
public static void sleep(int nSecond) 8(&C0_yD  
{ b\H~Ot[i  
try{ Zj!S('hSY  
Thread.sleep(nSecond); &eyFApM[Z  
} K*p^Gs,  
catch(Exception e) [+>$'Du  
{ v;{s@CM m  
e.printStackTrace (); oZP:}= F  
} HL
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} CEZ*a 0}=  
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//日志 aY8>#t?  
public static void log(String sMsg) Gz$Ds
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{ eH79,!=2  
System.err.println(sMsg); %xkq
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} P4ot,Q4  
Y{um1
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public static void log(int sMsg) a&4>xZU #  
{ rOH8W  
System.err.println(sMsg); O*!+D-  
} Q]7r?nEEhW  
} e-\J!E'1F  
,,b_x@y*  
980[]&(  
/* $UO7AHk  
**TestMethod.java - C8h$P  
*/ (F~eknJ  
package NetFox; T?NwSxGo  
Y!CZ?c)@  
)vhHlZ *+  
public class TestMethod { w/>k  
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;./Tv84I^  
public TestMethod() nBZqhtr  
{ ///xx/weblogic60b2_win.exe _9""3O  
try{ '<$(*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N2xgyKy~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !9OAMHa*9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); My Af~&Y+  
fileFetch.start(); ,7k)cNstW  
}
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catch(Exception e){e.printStackTrace ();} NuW9.6$Jrf  
2}'&38wMT  
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} LKftNSkg"  
!#g`R?:g  
{_KuztJGA  
public static void main(String[] args) 3-~_F*%ST  
{ ]:Ocu--  
new TestMethod(); J1P82=$,  
} 9akCvY#Q  
} );7csh%  
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