http断点续传简单实现（java)

/* 1$H*E~  
**SiteFileFetch.java ]hRCB=G  
*/ qXcHf6  
package NetFox; Jsde+G,N  
import java.io.*; -pvF~P?8U  
import java.net.*; :+06M@  
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public class SiteFileFetch extends Thread { 7b7@"Zw*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7,X5]U&A<x  
long[] nStartPos; //开始位置 D<%/:
M  
long[] nEndPos; //结束位置 Wb4+U;C^!'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .'aW~WR  
long nFileLength; //文件长度 hj[&.w  
boolean bFirst = true; //是否第一次取文件 u 6A!Sw  
boolean bStop = false; //停止标志 Xy0*1$IS]  
File tmpFile; //文件下载的临时信息 SHWD@WLE4  
DataOutputStream output; //输出到文件的输出流 g$+ $@~  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [TRHcz n  
public SiteFileFetch(SiteInfoBean bean) throws IOException |L wn<y  
{ ?> )(;Ir9  
siteInfoBean = bean; kyR=U`OW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Mwm9{1{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ())
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{ 6_}& WjU'  
bFirst = false; PaIE=Q4gJ  
read_nPos(); O(pa;&"  
} U~H]w,^  
else |}$ZOwc  
{ $IUe](a{d  
nStartPos = new long[bean.getNSplitter()]; FK ?g  
nEndPos = new long[bean.getNSplitter()]; \+3amkBe  
} v@n0ma=  
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} )/Z% HBn  
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public void run() jxeZ,w o  
{ *{TB<^ *  
//获得文件长度 9\f%+?p  
//分割文件 f~a]og5|G  
//实例FileSplitterFetch iTUOJ3V7i  
//启动FileSplitterFetch线程 ZE393FnE  
//等待子线程返回 ,Kl6vw8Htg  
try{ xWR<>Og.  
if(bFirst) A-S!Z2m\  
{ ):<9j"Z;At  
nFileLength = getFileSize(); 'TwvkU"  
if(nFileLength == -1) r" 4u)H>  
{ *M^(A}+O  
System.err.println("File Length is not known!"); <gfkbDP2  
} Lfr>y_i;F  
else if(nFileLength == -2) i?^lEqy[  
{ ?OD43y1rzd  
System.err.println("File is not access!"); $e#V^dph  
} _98 %?0  
else +T!7jC(O Q  
{ ip)gI&kN`z  
for(int i=0;i<nStartPos.length;i++) HnlCEW,^o  
{ #cGn5c}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S29k IJ  
} jq_E{Dq1  
for(int i=0;i<nEndPos.length-1;i++) X7."hGu@  
{ i`st'\I  
nEndPos = nStartPos[i+1]; dAba'|Y  
} $-4 Zi  
nEndPos[nEndPos.length-1] = nFileLength; 1[4 2f#  
} e]5 n4"]D)  
} OUM^u*  
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nA1059B  
//启动子线程 6O@/Y;5i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DWXxB  
for(int i=0;i<nStartPos.length;i++) @a~GHG[x  
{ QtSJ9;eP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), glL.CkJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (,P6cWt}"  
nStartPos,nEndPos,i); _-6IB>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5yl[#>qt  
fileSplitterFetch.start(); I_"KhBM  
} "~+?xke5z  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )Up'W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |K(jXZ)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fg?4/]*T6  
nEndPos = " + nFileLength); <13').F  
// fileSplitterFetch[nPos.length-1].start(); e^%>_U  
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//等待子线程结束 DuvI2ZWP]  
//int count = 0; (?W[#.=7  
//是否结束while循环 oj$^87KX  
boolean breakWhile = false; A(2!.Y 2?*  
3q}fDM(@J  
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while(!bStop) zt3y5'Nk  
{ 4).i4]%LH  
write_nPos(); 7c8A|E0\mF  
Utility.sleep(500); rfH'&k  
breakWhile = true; .e Jt]K  
#)BbW40f6  
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for(int i=0;i<nStartPos.length;i++) S!oG|%VuB#  
{ \""sf{S9  
if(!fileSplitterFetch.bDownOver) :i};]pR  
{ u6#FG9W7  
breakWhile = false; $>*TO1gb+  
break; kZU v/]Y.  
} ud`!X#e~  
} 99/`23YL  
if(breakWhile) 9*&RvsrX  
break; ]/cVlpZ{f  
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//count++; ;;{!wA+"D  
//if(count>4) azKiXr#_
(  
// siteStop(); j-}WA"  
} oU
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System.err.println("文件下载结束！"); z4B-fS]  
} /9wmc2  
catch(Exception e){e.printStackTrace ();} 0Z,a3)jcc  
} )}|b6{{<  
vw5f|Q92  
}<7S%?TY  
//获得文件长度 GYJ lX  
public long getFileSize() +r<d z  
{ I}hY @  
int nFileLength = -1; OA?pBA  
try{ 2leTEs5aK`  
URL url = new URL(siteInfoBean.getSSiteURL()); lKT<aYX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); 9*b(\Z)N  
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int responseCode=httpConnection.getResponseCode(); NpLO_-  
if(responseCode>=400) H4Lvw8G  
{ gq|]t<'  
processErrorCode(responseCode); H="E#AC%8/  
return -2; //-2 represent access is error ^6kE tTO*  
} WJ[ybzVj  
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String sHeader; ]Te,m}E  
8x/]H(J  
"> ]{t[Ib  
for(int i=1;;i++) xC}9W6  
{ ?BA~$|lfxu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @)< 3Z  
//Utility.log(in.readLine()); ?P>3~3 B  
sHeader=httpConnection.getHeaderFieldKey(i); eY'< UO  
if(sHeader!=null) u301xc,N<z  
{ -+)06BqF}  
if(sHeader.equals("Content-Length")) |
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{ tA{B~>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8}_M1w6v  
break; 58>C,+  
} [19QpK WM  
} Yn+d!w<3:  
else /t
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break; X:kqX[\>  
} q37d:Hp  
} |%~Zo:Q<$>  
catch(IOException e){e.printStackTrace ();} l'm\*=3  
catch(Exception e){e.printStackTrace ();} 1Ax{Y#<  
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Utility.log(nFileLength); 24b?6^8~k  
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return nFileLength; p?idl`?^3  
} d(!g9H  
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{I^@BW-  
//保存下载信息（文件指针位置） ,B8u?{O  
private void write_nPos() n=1_-)  
{ 8{)j"rghah  
try{ V X"!a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _i@4R<  
output.writeInt(nStartPos.length); sO$X5S C9
 
for(int i=0;i<nStartPos.length;i++) )z=L^ot  
{ EH~t<  
// output.writeLong(nPos); WT_4YM\bz  
output.writeLong(fileSplitterFetch.nStartPos); mR3-+dB/  
output.writeLong(fileSplitterFetch.nEndPos); 5!V%0EQqw  
} C;jV)hr6P  
output.close(); S( Vssi|y  
} ^X\SwgD2w  
catch(IOException e){e.printStackTrace ();} ve&"x Nz<  
catch(Exception e){e.printStackTrace ();} 5u=$m^@{  
} Ax{C ^u  
7%)KB4(\_
 
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//读取保存的下载信息（文件指针位置） u!@(u!Qz  
private void read_nPos() NR9=V  
{ l)K8.(2  
try{ O+ghw1/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <4%cKW0  
int nCount = input.readInt(); .d;|iwl  
nStartPos = new long[nCount]; }P*x/z~  
nEndPos = new long[nCount]; 'J1
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for(int i=0;i<nStartPos.length;i++) )1iqM]~;B  
{ mnm7{?#[  
nStartPos = input.readLong(); IDn$w^"  
nEndPos = input.readLong(); +JlPQ~5  
} ~/m=
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input.close(); dW#T1mB  
} Mo4k6@ht_  
catch(IOException e){e.printStackTrace ();} D@?Tq,
= [  
catch(Exception e){e.printStackTrace ();} ApSzkPv*  
} ^jB17z[  
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private void processErrorCode(int nErrorCode) kT12  
{ p"tCMB  
System.err.println("Error Code : " + nErrorCode); Wz&[cj  
} _/[}PQC6G  
,qu7XFYrY  
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//停止文件下载 d]r?mnN W  
public void siteStop() MiN|u  
{ C.N#y`g  
bStop = true; LCMZw6p  
for(int i=0;i<nStartPos.length;i++) <Gw>}/-^  
fileSplitterFetch.splitterStop(); reI4!,x  
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} |y.^F3PE  
} U-:"Wx%G  
//负责部分文件的抓取 \m%Z;xKG  
**FileSplitterFetch.java %n)H(QPW  
*/ 5KgAY;|  
package NetFox; {YMO8  
,vs#(d6G  
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import java.io.*; (U([T-H  
import java.net.*; {'NXJ!I;t  
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public class FileSplitterFetch extends Thread { ##5e:<c&[  
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String sURL; //File URL vf0 fa46  
long nStartPos; //File Snippet Start Position |*>s%nF|  
long nEndPos; //File Snippet End Position #I}w$j i  
int nThreadID; //Thread's ID b"pN;v  
boolean bDownOver = false; //Downing is over /C6$B)w_*{  
boolean bStop = false; //Stop identical 34:Y_*  
FileAccessI fileAccessI = null; //File Access interface 2OZ<t@\OY  
L#MgoBXr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1TlMB  
{ vWVQ8S.  
this.sURL = sURL; +HkEbR'G0  
this.nStartPos = nStart; 0WQd#l  
this.nEndPos = nEnd; 7 0Wy]8<P  
nThreadID = id; 5
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 z`:tl7  
} (q}{;  
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public void run() 7-("ppYX=  
{ AB=Wj*fr  
while(nStartPos < nEndPos && !bStop) RgSB?  
{ 2Kz407|'  
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try{ &xE+PfX  
URL url = new URL(sURL); s8+{##"1 q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EYR%u'&7'  
httpConnection.setRequestProperty("User-Agent","NetFox"); jZR2Nx}16  
String sProperty = "bytes="+nStartPos+"-"; k2:mIp\  
httpConnection.setRequestProperty("RANGE",sProperty); XM~eocn  
Utility.log(sProperty); iLk"lcX  
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InputStream input = httpConnection.getInputStream(); FV\$M6 _  
//logResponseHead(httpConnection); q'KXn0IY#  
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byte[] b = new byte[1024]; F0KNkL>&g  
int nRead; icN#8\E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R47tg&k6[  
{ TXbnK"XQ  
nStartPos += fileAccessI.write(b,0,nRead); g`I$U%a_2  
//if(nThreadID == 1) C
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 51'{Jx8  
} 9E2OCLWrE  
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Utility.log("Thread " + nThreadID + " is over!"); Sh(XF
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bDownOver = true; {nH*Wu*^  
//nPos = fileAccessI.write (b,0,nRead); .6A{   
} oH1]-Nl$  
catch(Exception e){e.printStackTrace ();} n0b{Jg *  
} M9QxF  
} 3\j3vcuy  
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l 9bg  
//打印回应的头信息 4\y>pXML-U  
public void logResponseHead(HttpURLConnection con) DAQozhP8  
{ [E;~Y_l  
for(int i=1;;i++) ;Swj`'7  
{ g-<[* nF  
String header=con.getHeaderFieldKey(i); 5@EX,$h  
if(header!=null) wpa^]l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VWW(=j  
Utility.log(header+" : "+con.getHeaderField(header)); u"-."_  
else ,B$e'KQ  
break; 1i}p?sU  
} (|sqN8SbA  
} V"5LNtf  
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public void splitterStop() xbsX-F  
{ 7l3
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bStop = true; D)bR-a_^  
} ZU.f)94u  
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} :tp{(MF  
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85ND 3F6q4  
/* ,8+Jt@L  
**FileAccess.java #Kt5+"+7  
*//文件访问(定位，写) v7mg8'  
package NetFox; 9ZG__R3B1\  
import java.io.*; m`#UV-$J  
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public class FileAccessI implements Serializable{ 4_w{
~  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J-W8wCq`  
RandomAccessFile oSavedFile; T^H`$;\  
long nPos; *wV`7\@  
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public FileAccessI() throws IOException ~i=5NUE  
{ X@Yl<9|i  
this("",0); !==C@cH<N  
} zqm/<]A*l  
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public FileAccessI(String sName,long nPos) throws IOException 8[d6 s  
{ q@}tv=}  
oSavedFile = new RandomAccessFile(sName,"rw"); GtkZ%<KF9  
this.nPos = nPos; ;xjw'%n,  
oSavedFile.seek(nPos); =EUi|T4:  
} g42f*~l  
uEdeA'*^  
/^b=| +Do  
public synchronized int write(byte[] b,int nStart,int nLen)
y])z,#%ED  
{ U_AmRiy  
int n = -1; :{x   
try{ o&kgRv[  
oSavedFile.write(b,nStart,nLen); Rs53R$PIR  
n = nLen; +6\1 d5  
} 9`5qVM1O{  
catch(IOException e) qWw{c&{Q],  
{ O],]\M{GL  
e.printStackTrace (); 7-[^0qS  
} U&L?IT=x  
UE 
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return n; ThYHVJ[;  
} CChCxB  
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} hlBqcOpkKg  
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cfUG)-]P~  
/* FWuk@t[<O  
**SiteInfoBean.java i`EG80\[Z  
*/ qh/}/Sl;  
package NetFox; H6i;MQ  
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public class SiteInfoBean { wj|[a,(r  
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private String sSiteURL; //Site's URL H1a<&7  
private String sFilePath; //Saved File's Path Rx.dM_S  
private String sFileName; //Saved File's Name |gM@}!DL  
private int nSplitter; //Count of Splited Downloading File ]VHO'z\m  
}y
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public SiteInfoBean() 8?&!@3n  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 h0Ilxa   
this("","","",5); PVX23y;  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nVv=smVOt  
{ KmaMS(A(3  
sSiteURL= sURL; _kJW/3eE  
sFilePath = sPath; SD=9fh0l  
sFileName = sName; w$[ck=  
this.nSplitter = nSpiltter; .dl4f"k  
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} cA2
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!&@
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public String getSSiteURL() 46M?Gfd,X  
{ bs\7 juHt  
return sSiteURL; D7OPFN7`  
} !F~*Q2PZ9  
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public void setSSiteURL(String value) 9xIz[`)i.  
{ ("ulL5  
sSiteURL = value; ff.;6R\  
} i8>^{GODR  
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public String getSFilePath() }pL#C  
{ 0ZjinWkR[  
return sFilePath; SKrkB~%z  
} wEMg~Hh  
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public void setSFilePath(String value) @/0-`Y@?  
{ ^{w]r5d  
sFilePath = value; ;_?RPWZ;MO  
} o+ 0"@B  
H?W8_XiN  
hF7#i_UN<  
public String getSFileName() 4/M~#  
{ 2N[S*#~*e  
return sFileName; I,wgu:}P#  
} <-K'9ut,  
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public void setSFileName(String value) LFT)_DG7(  
{ ;PF!=8dW  
sFileName = value; KI~M.2pk  
} n0<I  
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public int getNSplitter() .Pi8c[  
{ k\`~v$R3  
return nSplitter; YQ#o3sjs  
} sQ>L3F;A`  
~
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F)^:WWVc#  
public void setNSplitter(int nCount) ~Bs=[TNd[  
{ lgaE2`0 [3  
nSplitter = nCount; y{]iwO;  
} V [KFZSA  
} 6N {|;R@2  
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/* ibIo1i//[  
**Utility.java Aq:1  
*/ `UDB9Ca  
package NetFox; D4e!A@LJ  
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public class Utility { )Me$BK>  
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public Utility() R@K

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{ 2%*mL98WK  
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} U";8zplU  
,ThN/GkSC  
//线程睡眠 ;u "BCW  
public static void sleep(int nSecond) )S2GPn7  
{ 0281"a
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try{ L5
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Thread.sleep(nSecond); l'0fRQc  
}  YD|;xuh  
catch(Exception e) Nn]|#lLP  
{ <W<>=vDzyE  
e.printStackTrace (); Wz]ny3K[.  
} 896oz>  
} N(@B3%H2/J  
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//日志 WY 'Qhi
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public static void log(String sMsg) lZ![?t}2`  
{ c.;}e:)s  
System.err.println(sMsg); wz{]CQ7"  
} ?z
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IGC:zZ~z  
O${B)C,  
public static void log(int sMsg) N,M[Opm  
{ LWp#i8,  
System.err.println(sMsg); 0v/}W(  
} z1R_a=7  
} PH]/*LEj  
0M_~@E*&  
3!:?OUhx  
/* EiP#xjn?c  
**TestMethod.java ;('(Yn7~  
*/ \sZT[42  
package NetFox; +M^+qt;]V  
{i09e1  
R%\K<#^\  
public class TestMethod { ^< o"3?  
z;#]xCV  
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public TestMethod() Hk8pKpn3  
{ ///xx/weblogic60b2_win.exe `C+>PCO  
try{ n?=d)[]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B{ptP4As-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); aUTXg60l*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ta'{S=^j  
fileFetch.start(); 'W2B**}  
} ?7]UbtW[  
catch(Exception e){e.printStackTrace ();} / 80Q  
@P@j9yR  
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} aIXN wnq  
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public static void main(String[] args) 9nrmz>es|-  
{ td"D&1eQ@  
new TestMethod();
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} 8,DY0PGP  
} 9J $"Qt5;6  
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