http断点续传简单实现（java)

/* ~

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**SiteFileFetch.java }ABHGr5[  
*/ xiQ;lE   
package NetFox; tNCKL.yU  
import java.io.*; i- r y5x  
import java.net.*; jVdB- y/r  
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public class SiteFileFetch extends Thread { r$-]NYPi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "_e/O&-cH  
long[] nStartPos; //开始位置 ,?s:s&4  
long[] nEndPos; //结束位置 M \3Zj(E/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `Yc>I!iN  
long nFileLength; //文件长度 X !l#1  
boolean bFirst = true; //是否第一次取文件 -j"2rIl4#  
boolean bStop = false; //停止标志 5}2XnM2  
File tmpFile; //文件下载的临时信息 aD8r:S\  
DataOutputStream output; //输出到文件的输出流 x)o`w"]al  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {siIRl2&  
public SiteFileFetch(SiteInfoBean bean) throws IOException C@s;0-qL  
{ d<4q%y'X{  
siteInfoBean = bean; nD;8)VI'I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fHwr6"DJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \}mn"y  
if(tmpFile.exists ()) #me'1/z  
{ p*(]8pDC  
bFirst = false; V .VV:`S  
read_nPos(); 5*7 \Yjk?  
} qct:xviH<|  
else a,*~wmg  
{ 1]Gp\P}  
nStartPos = new long[bean.getNSplitter()]; UI.>BZ6}  
nEndPos = new long[bean.getNSplitter()]; uSK<{UT~3  
} $WK~|+"{>  
3
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} rui]_Fn]I  
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public void run() .[4Dvt|>6  
{ F^|4nBd*ub  
//获得文件长度 6)~J5Fb  
//分割文件 \)n'Ywr  
//实例FileSplitterFetch >0qe*4n|M  
//启动FileSplitterFetch线程 G8_|w6  
//等待子线程返回 . 'rC'FT  
try{ SV96eYT<  
if(bFirst) O<?z\yBtS^  
{ -|~tZuf  
nFileLength = getFileSize(); ,BG L|5?3z  
if(nFileLength == -1) 9N]V F'  
{ 2DTBL:?`  
System.err.println("File Length is not known!"); ,,[pc  
} :IlJQ{=W  
else if(nFileLength == -2) )S6"I  
{ ^J Y]w^u  
System.err.println("File is not access!"); 73OYHp_j  
} (Cjw^P|Y@  
else uKocEWB=/F  
{ H '(Ky  
for(int i=0;i<nStartPos.length;i++) Bys_8x}  
{ @fxDe[J:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CERT`W%o  
} ;v^1V+1:z  
for(int i=0;i<nEndPos.length-1;i++) J 4OgV?  
{ ,a/<t"  
nEndPos = nStartPos[i+1]; Cn>RUGoUsI  
} D#G(&<Q  
nEndPos[nEndPos.length-1] = nFileLength; Lcpz(W^  
} Y^@Nvt$<K  
} 1WW`%  
R s)Nz< d  
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//启动子线程 9!sR}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ki:.^  
for(int i=0;i<nStartPos.length;i++) ,HE +|y#  
{ IDpW5Dc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _Q1[t9P"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MKN],l N  
nStartPos,nEndPos,i); 9xm'0 '  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d2e4=/A%  
fileSplitterFetch.start(); Zr.6J*&!  
} `upxM0gc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <..|:0Q&~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1v^eXvY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \E<t'\>@X  
nEndPos = " + nFileLength); [10;Mg  
// fileSplitterFetch[nPos.length-1].start(); UI>?"b6 L  
1]<wZV}.  

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//等待子线程结束 gP?uLnzvi  
//int count = 0; )W& $FU4JK  
//是否结束while循环  1ZF>e`t8  
boolean breakWhile = false; %IbG@}54  
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while(!bStop) mt(2HBNoz  
{ ?yq1\G)]  
write_nPos(); .s!qf!{V`  
Utility.sleep(500); eBW=bK~[VP  
breakWhile = true; !w9w{dtW=  
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for(int i=0;i<nStartPos.length;i++) 3M[b)At V.  
{ BcvCm+.S:  
if(!fileSplitterFetch.bDownOver) <x|P}  
{ _#8OHG.x  
breakWhile = false; AGdFJ>/  
break; cKKl\g@}  
} \%FEQa0u  
} +w]KK6  
if(breakWhile) 9 ZD4Gv   
break; Lh(`9(tX  
1/H9(2{L  
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//count++; Do&/+Ssnu  
//if(count>4) PnKgUJoa0  
// siteStop(); _26<}&]b*  
} =R
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System.err.println("文件下载结束！"); LZB=vc|3/  
} O*ql!9}E{  
catch(Exception e){e.printStackTrace ();} x(Us O}  
} 0Lo)Ni^"  
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//获得文件长度 8JU9Qb]L'I  
public long getFileSize() ?<iinx   
{ 0;kp`hB  
int nFileLength = -1; $#/-+>  
try{ |9F^"7Q~C  
URL url = new URL(siteInfoBean.getSSiteURL()); w<ol$2&B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); / ao|v  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2V1|b`b#4  
BSGC.>$s  
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int responseCode=httpConnection.getResponseCode(); tC,R^${#  
if(responseCode>=400) 5Cp6$V|/kv  
{ !Cpy )D(  
processErrorCode(responseCode); x
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return -2; //-2 represent access is error k
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} (0=e ,1 n  
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String sHeader; ugwZAC  
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FKOTv2  
for(int i=1;;i++) 12yr_   
{ SGd[cA Ko  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z|o7k;raH  
//Utility.log(in.readLine()); fU )@Lj1Wo  
sHeader=httpConnection.getHeaderFieldKey(i); #]iSh(|8  
if(sHeader!=null) 6Ch [!=p{  
{ DO#!ce  
if(sHeader.equals("Content-Length")) D[7+xAwS  
{ )NoNgU\7!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R3;,EL{H&  
break; FG^Jh5  
} fR&;E  
} 6,707h  
else '9+JaB  
break; }J~ d6m  
} R<J1bH1n3  
} p6M
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catch(IOException e){e.printStackTrace ();} c/G4@D>  
catch(Exception e){e.printStackTrace ();} 7Z#r9Vr  
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Utility.log(nFileLength); vnNX)$f  
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return nFileLength; {
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} 6z6\-45  
a,GOS:?O5  
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//保存下载信息（文件指针位置） (V:z7  
private void write_nPos()  =V- ^  
{ 8gQg#^,(t  
try{ [O"9OW'2!B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k//l~A9m  
output.writeInt(nStartPos.length); X7cqAi  
for(int i=0;i<nStartPos.length;i++) |4J ;s7us  
{ 3KyIBrdi?  
// output.writeLong(nPos); +:a#+]g  
output.writeLong(fileSplitterFetch.nStartPos); =i4%KF9x  
output.writeLong(fileSplitterFetch.nEndPos); >tmv3_<=  
} S~~G0GiW  
output.close(); "~1{|lj|)  
} Y ,Iv<Hg  
catch(IOException e){e.printStackTrace ();} \F$Vm'f_  
catch(Exception e){e.printStackTrace ();} r9nyEzk  
} r~K5jL%z9  
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//读取保存的下载信息（文件指针位置） BwLggo  
private void read_nPos() i#&iT P`  
{ r%craf  
try{ *LaL('.>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g[D(]t\#x  
int nCount = input.readInt(); Y<4
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nStartPos = new long[nCount]; -x~4@~  
nEndPos = new long[nCount]; WE-cq1)  
for(int i=0;i<nStartPos.length;i++) s?fO)7ly  
{ +f}u.T_#  
nStartPos = input.readLong(); k10g %K4g  
nEndPos = input.readLong(); ~rUcko8  
} 5^,"Ve|  
input.close(); +N|}6e  
} &V`~ z e  
catch(IOException e){e.printStackTrace ();} I@$cw
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catch(Exception e){e.printStackTrace ();} '7oW
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} yHXQCWY{8;  
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private void processErrorCode(int nErrorCode) %4=
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{ U<YP
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System.err.println("Error Code : " + nErrorCode); \aEarIX#*  
} AHo4% 5  
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//停止文件下载 _d[4EY  
public void siteStop() -4%{Jb-1  
{ g< F7UA  
bStop = true; &>@  
for(int i=0;i<nStartPos.length;i++) hT=6XO od4  
fileSplitterFetch.splitterStop(); #nD]G#>e  
#FZoi:'Q  
4x2 ;@Pd  
} !08\w
@  
} >FR;Ux~a  
//负责部分文件的抓取 A-&'/IHR"B  
**FileSplitterFetch.java )YtdU(^J$  
*/ ~7G@S&<PK(  
package NetFox; e5s=@-[  
W$>AK_Y}  
wN+3OPM  
import java.io.*; tL#]G?0d  
import java.net.*; pV^(8!+  
&OMe'P  
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public class FileSplitterFetch extends Thread { <o aVI?  
Vx~N`|yY  
#:)yh]MP  
String sURL; //File URL pX/42W  
long nStartPos; //File Snippet Start Position )y .1}R2[  
long nEndPos; //File Snippet End Position CJ~gE"  
int nThreadID; //Thread's ID URo#0fV4C  
boolean bDownOver = false; //Downing is over Xi:y35q  
boolean bStop = false; //Stop identical -4=\uvYh  
FileAccessI fileAccessI = null; //File Access interface Dcep^8'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zv"qA  
{ =o+js;3  
this.sURL = sURL; Qy!;RaA3T  
this.nStartPos = nStart; s|O4>LsG  
this.nEndPos = nEnd; (2l?~CaK  
nThreadID = id; wn&5Ul9Elb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A7hWAq  
} >T)#KQ1t  
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public void run() {SOy-  
{ n a3st*3V_  
while(nStartPos < nEndPos && !bStop) K!A;C#b!  
{ {+
@M!  

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try{ bQBYzvd  
URL url = new URL(sURL); a$2WL g,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VcpN PU6  
httpConnection.setRequestProperty("User-Agent","NetFox"); LP:U6 Z  
String sProperty = "bytes="+nStartPos+"-"; Ew$-,KC[  
httpConnection.setRequestProperty("RANGE",sProperty); bG&vCH;}%  
Utility.log(sProperty); c8}jO=/5+  
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InputStream input = httpConnection.getInputStream(); 0?/vcsO  
//logResponseHead(httpConnection); dePI&z:  
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byte[] b = new byte[1024]; =!P  
int nRead; }$D{YHF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eczS(KoL4  
{ OJTEvb6nPg  
nStartPos += fileAccessI.write(b,0,nRead); t#sw{RO  
//if(nThreadID == 1) .p?kAf`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |p"4cG?)  
} ; +%|!~  
]~J.YX9ST  
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Utility.log("Thread " + nThreadID + " is over!"); }\wTV*n`X  
bDownOver = true; n&;-rj^qq  
//nPos = fileAccessI.write (b,0,nRead); Qe;j_ BH  
} q@8j[15  
catch(Exception e){e.printStackTrace ();} avwhGys#  
} <'l;j"&lp  
} xGVL|/?8  
]CZ&JL  
.BqSE  
//打印回应的头信息 x"xtILrI  
public void logResponseHead(HttpURLConnection con) o^b4l'&o  
{ qwmZOR#  
for(int i=1;;i++) mIUpAOC`"Z  
{ &]euL:C  
String header=con.getHeaderFieldKey(i); \5=fC9*G  
if(header!=null) '@ C\,E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pGhA  
Utility.log(header+" : "+con.getHeaderField(header)); 3t^r;b  
else L?~-<k  
break; Kl)PF),  
} gt= _;KZ  
} fsVQZ$h73  
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public void splitterStop() q9mYhT/Im  
{ p/GYfa dU  
bStop = true; AroXf#.  
} xs ^$fn\  
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} q9`!T4,  
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/* P0N%77p>"  
**FileAccess.java 2~BId&]  
*//文件访问(定位，写) 3cztMi  
package NetFox; ?]bZ
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import java.io.*; I%q&4L7pj  
rBUdHd9  
#Kp/AN5YC  
public class FileAccessI implements Serializable{ oztfr<cUH  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WF{rrU:  
RandomAccessFile oSavedFile; Gj}P6V_  
long nPos; BHW8zY=F  
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public FileAccessI() throws IOException hiN6]jL|O  
{ -{A!zTw1w  
this("",0); 9G'Q3? z  
} D{!NTr  
"77 j(Vs9  
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public FileAccessI(String sName,long nPos) throws IOException R;*3";+v|:  
{ N>$Nw<wV  
oSavedFile = new RandomAccessFile(sName,"rw"); t6)wR  
this.nPos = nPos; ,Uh7Q-vd  
oSavedFile.seek(nPos); 1Lf:TQB  
} =os%22*  
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9V%
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public synchronized int write(byte[] b,int nStart,int nLen) Ba],ONM4k  
{ *CH lg1  
int n = -1; <Eo;CaaF/  
try{ _e;$Y#`EO  
oSavedFile.write(b,nStart,nLen); z$d/Vz,a  
n = nLen; ,\FJVS;NeJ  
} Y M_\ ZK:  
catch(IOException e) i-b++R/WN  
{ 7xOrG],E  
e.printStackTrace (); wER>a (  
} '14 G0<;yL  
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return n; 45hjN6   
} Bk~lE]Q3c7  
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} Vc!;O9dP  
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/* w6fVZY4  
**SiteInfoBean.java ( *(#;|m  
*/ ^fLePsmd  
package NetFox; IQS:tL/  
T>&d/$;]  
wnL\.%Y^  
public class SiteInfoBean { =-`}(b2N  
*:q3<\y{  
pN)9GO5  
private String sSiteURL; //Site's URL @eRR#
S  
private String sFilePath; //Saved File's Path i'5Q.uX  
private String sFileName; //Saved File's Name _U.D*f<3)  
private int nSplitter; //Count of Splited Downloading File n+M:0{Y|  
.O{2]e$  
1Z +3=$P  
public SiteInfoBean() [=Y@Ul  
{//nSplitter的缺省值为5 1}C|Javkn  
//default value of nSplitter is 5 /3!
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this("","","",5); 8Vkw vc  
} gsn3]^X  
O;9'0-F ?  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?*
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{ bUf2uWy7  
sSiteURL= sURL; [<Wo7G1s  
sFilePath = sPath; l
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sFileName = sName; y#:_K(A" k  
this.nSplitter = nSpiltter; 8'Z#sM^E  
FY [WdZDZ  
,%#FK|  
} L\Uf+d:&}G  
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public String getSSiteURL() *.0}3  
{ ')w:`8Tl  
return sSiteURL; m]8rljo  
} K14e"w%6rs  
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public void setSSiteURL(String value) 05mjV6j7m  
{ >(s)S[\  
sSiteURL = value; 31\l0Jg  
} t<M^/xe2  
V,<3uQD9a  
#1i&!et&/  
public String getSFilePath() C9[Jr)QX  
{ hPa:>e  
return sFilePath; ^uIP   
} tCAh?nR  
6eqxwj{S[  
<(dHh9$~  
public void setSFilePath(String value) }>I|\Z0I  
{ )<bgZ, v  
sFilePath = value; 5o 4\Jwt  
} =m.Lw  
v/{LC
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public String getSFileName() kw&,<V77~  
{ =X[]0.I%  
return sFileName; )mw#MTv<[  
} !63
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tLXwszR0r  
public void setSFileName(String value) #T1py@b0zA  
{ YIv!\`^ \  
sFileName = value; 3-z
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} ]zEatY  
1*\JqCR  
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public int getNSplitter() fvn`$  
{ DD`Bl1)  
return nSplitter; &~of]A  
} Q>Rjv.1  
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u`I&&  
public void setNSplitter(int nCount) ]n9o=^q/  
{ o!W 71  
nSplitter = nCount; ol QT r  
} fYrC;&n  
} @X@?jj&  
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{"T$jV:GB  
/* $VOSd<87  
**Utility.java HriY-=ji>a  
*/ :.wR*E  
package NetFox; .J0s_[  
bBwQ1,c$  
iV#sMJN9  
public class Utility { %M8m 8 )  
7kX;|NA1  
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public Utility() XpWcf ([  
{ >yk@t&j,  
coa+@g,w7#  
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} L?_'OwaY  
1t&LNIc|^  
//线程睡眠 a6\0XVU  
public static void sleep(int nSecond) ~6YTm6o  
{ cu{c:z~  
try{ m'{gO9V  
Thread.sleep(nSecond); jeb]3i=pw  
} e ]-fb{oVH  
catch(Exception e) |q0F*\z3  
{ X{cFqW7  
e.printStackTrace (); D6X0(pU0  
} D%[yAr;r  
} mX8k4$z  
^n Gj 7b  
//日志 Hw"LoVh  
public static void log(String sMsg) r<< ]41  
{ t&5N{C:  
System.err.println(sMsg); O5X@'.#rU  
} 8EbJ5wu/%S  
?|4Y(0N  
%gBulvg
 
public static void log(int sMsg) w[ )97d  
{ ,#n$YT7  
System.err.println(sMsg); N@}5Fnk-  
} (*qMs)~]B  
} >\f'QQ  
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/* jEK{QOq0  
**TestMethod.java b
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*/ KZea
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package NetFox; ^w|D^F=o  
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K=Q<G:+&V  
public class TestMethod { \%],pZsA~  
{Xr|L  
$TU:iv1Fm  
public TestMethod() b*5Yy/U  
{ ///xx/weblogic60b2_win.exe 0c{-$K}  
try{ LIah'6qR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qqm$Jl!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #_(t46  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4hl`~&yDf  
fileFetch.start(); +"yt/9AO  
} n]nb+_-97  
catch(Exception e){e.printStackTrace ();} F7!q18ew  
|$^a"Yd`9  
:"Gx  
} $u"*n\k>  
+cXdF  
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public static void main(String[] args) I_.Jo `lK~  
{ n0 q$/Y.  
new TestMethod(); S+*%u/;l  
} 6}/m~m  
} ]ykMh  
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