http断点续传简单实现（java)

/* =xRxr@  
**SiteFileFetch.java }!@X(S!do  
*/ R1C2d+L  
package NetFox; -SKcS#IF  
import java.io.*; f}{Oj-:"CC  
import java.net.*; <x\I*%(  
<(B: "wI  
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public class SiteFileFetch extends Thread { }R)A%FKi@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean psB9~EU&Q  
long[] nStartPos; //开始位置 Tg/rV5@ka  
long[] nEndPos; //结束位置 VMV~K7%0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6cbIs_g  
long nFileLength; //文件长度 @-Ln* 3n  
boolean bFirst = true; //是否第一次取文件 gclw>((5  
boolean bStop = false; //停止标志 yMBFw:/o  
File tmpFile; //文件下载的临时信息 #{|
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DataOutputStream output; //输出到文件的输出流 BxHfL8$1[$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FHbw&  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6%2\bI.#  
{ Dv-ubki  
siteInfoBean = bean; 'EsdYx5C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,)P6fa/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j!hdi-aTU  
if(tmpFile.exists ()) cO/.(KBF  
{ AX2On}&bf  
bFirst = false; 6'QlC+E  
read_nPos(); rklK=W z  
} 7s.vJdA]6  
else iV8O<en&i  
{ S`Wau/7t  
nStartPos = new long[bean.getNSplitter()]; 7="I;  
nEndPos = new long[bean.getNSplitter()]; `KzNBH,W  
} t/0h)mL}  
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} !:w&eFC6  
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public void run() Ncle8=8  
{ ctWH?b/ua  
//获得文件长度 M8iI e:{ c  
//分割文件 !ie'}|c  
//实例FileSplitterFetch ejI nJ  
//启动FileSplitterFetch线程 CXfPC[o  
//等待子线程返回 EHY}gG)  
try{ n8vteGQ  
if(bFirst) T*8rR"  
{ <zE~N~;  
nFileLength = getFileSize(); &Eqa y'  
if(nFileLength == -1) WnZn$N.  
{ CPS1b  
System.err.println("File Length is not known!"); b\H !\A  
} dqo&3^px  
else if(nFileLength == -2) biw2f~V  
{ NA9N#;  
System.err.println("File is not access!"); j[y,Jch  
} p{k^)5CR/  
else [_SV$Jz  
{ *{e?%!Q  
for(int i=0;i<nStartPos.length;i++) gm}[`GMU  
{ &H<n76G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Fi!XaO  
} pswEIa  
for(int i=0;i<nEndPos.length-1;i++) bEc @"^)  
{ /WX 0}mWu  
nEndPos = nStartPos[i+1]; x9{&rldC  
} GVlTW?5  
nEndPos[nEndPos.length-1] = nFileLength; #>/stU-  
} c (Gl3^  
} >4N=
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//启动子线程 q VcZF7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4RXF.kJ3=  
for(int i=0;i<nStartPos.length;i++) ~'aK[3  
{ ;YK{[$F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]fgYO+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =
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nStartPos,nEndPos,i); $NG|z0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (#"iZv,  
fileSplitterFetch.start(); |zaYIVE[  
} +,BJ4``*k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F;,LY:s|Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GE0,d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c6 tB9b  
nEndPos = " + nFileLength); 3+v+_I>%k  
// fileSplitterFetch[nPos.length-1].start(); l~v BA$,  
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Q|`sYm'.  
//等待子线程结束 ,9:0T LLR  
//int count = 0; %G%D[ i]  
//是否结束while循环 u(`,7 o "  
boolean breakWhile = false; EhBYmc"&  
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while(!bStop) Z} 8
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{ NpIx\\d  
write_nPos(); HAi'0%"  
Utility.sleep(500); H)
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breakWhile = true; ys3&$G  
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for(int i=0;i<nStartPos.length;i++) k^ZcgHHgb  
{ '#fwNbD  
if(!fileSplitterFetch.bDownOver) gZ^NdDBO  
{ o1"-x  
breakWhile = false; '*PJ-=G  
break; O\(0{qu  
} eI 6G  
} UUF;Q0X  
if(breakWhile) V+M=@Pvp9  
break; #z*-  
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//count++; }4; \sY  
//if(count>4) v$H]=y  
// siteStop(); v/Z!Wp1LV  
} b\U p(]  
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System.err.println("文件下载结束！"); l9%oKJ;  
} wjr1?c  
catch(Exception e){e.printStackTrace ();} GV5hmDzRs  
} W+'|zhn  
#_, l7q8U  
pV3o\bk!  
//获得文件长度 Lb'HM-d  
public long getFileSize() tWNz:V  
{ fh1rmet&Ts  
int nFileLength = -1; DKjkO5R\  
try{ >|Hd*pg))  
URL url = new URL(siteInfoBean.getSSiteURL()); d`z),A=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J(\]39y  
httpConnection.setRequestProperty("User-Agent","NetFox"); N*C"+2  
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int responseCode=httpConnection.getResponseCode(); )_bR"!Z  
if(responseCode>=400) oM=Ltxv}  
{ B/(]AWi+  
processErrorCode(responseCode); @q?zh'@;  
return -2; //-2 represent access is error <fJ*{$[p  
} DL^}?Ve  
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String sHeader; vKzq7E  
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for(int i=1;;i++) ;xnJ+$//U  
{ ::\7s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L{hP&8$k  
//Utility.log(in.readLine()); H+]>*^'8  
sHeader=httpConnection.getHeaderFieldKey(i); !,mv 7Yj  
if(sHeader!=null) (f^K\7HM  
{ D(MolsKc?  
if(sHeader.equals("Content-Length")) 7*e7P[LQU  
{ Zd/ACZ[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pU4B6
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break; IH;+pN  
} 0L "+,  
} V@0Z\&  
else ~aK@M4  
break; s2*^ PG  
} FbMX?T"yH  
} SBnwlM"AN  
catch(IOException e){e.printStackTrace ();} 6.z8!4fpl  
catch(Exception e){e.printStackTrace ();} `ySm
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:%M[|Fj  
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Utility.log(nFileLength); `%lgT+~T  
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return nFileLength; 26fbBt8nP  
} ^^[MDjNy@  
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:I(-@2?{  
//保存下载信息（文件指针位置） \;w+_<zE5{  
private void write_nPos() D2$"!7O1H  
{ 3YyB0BMW  
try{ CwKo'PAJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S ^?&a5{o  
output.writeInt(nStartPos.length); (>
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for(int i=0;i<nStartPos.length;i++) f n9[Li  
{ :eQ?gM!,  
// output.writeLong(nPos); V 0Ul`  
output.writeLong(fileSplitterFetch.nStartPos); 4qtjP8Zv[  
output.writeLong(fileSplitterFetch.nEndPos); "]}+QK_  
} 
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output.close(); Py$*c  
} OO.. Y  
catch(IOException e){e.printStackTrace ();} 9QaEUy*,  
catch(Exception e){e.printStackTrace ();} >|jSd2_p  
} ?MevPy`H  
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//读取保存的下载信息（文件指针位置） ,bRvj8"M  
private void read_nPos() C'C'@?]  
{ C<CE!|sfr  
try{ Sr)rKc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /esSM~*H  
int nCount = input.readInt(); 0r=:l/Pz  
nStartPos = new long[nCount]; =T$-idx1l  
nEndPos = new long[nCount]; f $MVgX  
for(int i=0;i<nStartPos.length;i++) MF/359r)Et  
{ ^|DI9G(Bs  
nStartPos = input.readLong(); ^\kv>WBE  
nEndPos = input.readLong(); hv 18V>8  
} 
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input.close(); *V(TNLIh;  
} "J(#|v0  
catch(IOException e){e.printStackTrace ();} 1bb~u/j
U  
catch(Exception e){e.printStackTrace ();} 'ypJGm  
} is`Eqcj`dr  
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private void processErrorCode(int nErrorCode) h
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{ ckRWVw   
System.err.println("Error Code : " + nErrorCode); 0IoS|P}6a  
} /X)fWO S6  
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//停止文件下载 $aT
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public void siteStop() RO,  
{ C,:3z  
bStop = true; |S#)[83*3  
for(int i=0;i<nStartPos.length;i++) 1lu_<?O  
fileSplitterFetch.splitterStop(); 0%.l|~CE&  
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} f,z_|e  
} CZg$I&x  
//负责部分文件的抓取 }ex2tkz  
**FileSplitterFetch.java O$+J{@  
*/ rWI6L3,i+  
package NetFox; $d.UF!s  
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import java.io.*; 3=V79&  
import java.net.*; h_L-M}{OG  
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public class FileSplitterFetch extends Thread { 75}BI&t3k  

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String sURL; //File URL !Q
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long nStartPos; //File Snippet Start Position /,A:HM>B  
long nEndPos; //File Snippet End Position <<K GS  
int nThreadID; //Thread's ID ve_TpP  
boolean bDownOver = false; //Downing is over "<x%kD  
boolean bStop = false; //Stop identical d(zBd=;  
FileAccessI fileAccessI = null; //File Access interface n%? bMDS  
d4F3!*@(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Lh0Pvq0C  
{ ax&,  
this.sURL = sURL; DE:FWD<}  
this.nStartPos = nStart; 0|n1O)>J
 
this.nEndPos = nEnd; OF'y]W&  
nThreadID = id; E\&~S+:Xp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z/(^E8F  
} q-O=Em<*  
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public void run() <rV3(qb#]J  
{ ,[&@?  
while(nStartPos < nEndPos && !bStop) <eKF  
{ 9mfqr$3  
}stc]L{79  
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try{ JSCe86a7<E  
URL url = new URL(sURL); 0L1NZY^!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kf#9-.}?  
httpConnection.setRequestProperty("User-Agent","NetFox"); d-w#\ ^  
String sProperty = "bytes="+nStartPos+"-"; AdDlS~\?  
httpConnection.setRequestProperty("RANGE",sProperty); $Kn{x!,"(  
Utility.log(sProperty); Lgl%fO/<t  
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InputStream input = httpConnection.getInputStream(); ]wCg'EUB  
//logResponseHead(httpConnection); 1:5jUUL8  
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byte[] b = new byte[1024]; GF[onfQY7  
int nRead; dq[X:3i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JJ_77i  
{ `MtI>x c  
nStartPos += fileAccessI.write(b,0,nRead); A7,TM&  
//if(nThreadID == 1) ^\:"o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gOaL4tu  
} 0w[#`  
@%mJw u  
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Utility.log("Thread " + nThreadID + " is over!"); Obwj=_+upd  
bDownOver = true; CqGi 2<2  
//nPos = fileAccessI.write (b,0,nRead); f&x7g.I  
} >.^/Z/[.L  
catch(Exception e){e.printStackTrace ();} 4,kdP)Md$  
} @X\-c2=  
} $A"C1)d;  
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//打印回应的头信息 M{:}.H<a  
public void logResponseHead(HttpURLConnection con) rbfP6t:c3  
{ >;I$&  
for(int i=1;;i++) 8bT]NvCA  
{ 08*bYJu  
String header=con.getHeaderFieldKey(i); kOi@QLdN  
if(header!=null) >S\D+1PV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); imGg3'  
Utility.log(header+" : "+con.getHeaderField(header)); tB-0wD=PR  
else "SGq$3D  
break; mOm_a9ML  
} R0|dKKzS  
} !>gi9z,  
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public void splitterStop() w<}kY|A"=-  
{ \C<|yD  
bStop = true; ?4p\ujc  
} 1?k{jt~  
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} &z'NQ!uV  
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/* :zN{>,sC  
**FileAccess.java ,ddoI
I  
*//文件访问(定位，写) L-J 7z+{  
package NetFox; $Sz@u"ig%  
import java.io.*; ~cC=DeX  
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*2nQZ^c.  
public class FileAccessI implements Serializable{ LmCr[9/  
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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 !'yCB9]O  
RandomAccessFile oSavedFile; X*4iNyIs_  
long nPos; $q}zW%  
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public FileAccessI() throws IOException .X2fu/}  
{ j.}@9  
this("",0); tsGt,]O30  
} ~f:y^`+Q[  
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public FileAccessI(String sName,long nPos) throws IOException No
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{ nYA@t=t0  
oSavedFile = new RandomAccessFile(sName,"rw"); B4uJT~,7>  
this.nPos = nPos; PIo8mf/  
oSavedFile.seek(nPos); c;RL<83:  
} [Un~]E.'J  
F},#%_4  
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public synchronized int write(byte[] b,int nStart,int nLen) 7IEG%FY T  
{ 9V]{q  
int n = -1; yX`5x^wVw  
try{ 
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oSavedFile.write(b,nStart,nLen); 6!QY)H^j9,  
n = nLen; 9i^dQV.U=  
} 8ch^e[U`  
catch(IOException e) "W"
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{ Ne!0`^`~  
e.printStackTrace (); 0`=>/Wr39  
} s|cL mL[  
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return n; "A4.2  
} f+WN=-F\  
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} ktEdbALK  
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^KlW"2:  
/* 5LYzX+a)  
**SiteInfoBean.java QDHTP|2e  
*/ _MmSi4]yd  
package NetFox; 6Fe$'TP  
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public class SiteInfoBean { bE6:pGr  
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private String sSiteURL; //Site's URL h!zev~u1)`  
private String sFilePath; //Saved File's Path o<\uH
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private String sFileName; //Saved File's Name }w|a^=HAp  
private int nSplitter; //Count of Splited Downloading File G+SMH`h  
57S!X|CE  
C1M @;  
public SiteInfoBean() >[qoNy;  
{//nSplitter的缺省值为5 GKg&lM!O$  
//default value of nSplitter is 5 xIb"8,N  
this("","","",5); "<=HmE-;  
} qOD:+b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "<Q,|
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{ i^Ip+J+[  
sSiteURL= sURL; 4UISuYg'  
sFilePath = sPath; t/KH`  
sFileName = sName; '[zy%<2sL  
this.nSplitter = nSpiltter; "0sk(kT  
0)0,&@])7  
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} 9l&4mt;+&<  
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public String getSSiteURL() ?]/"AWUX  
{ IPa)+ ZQ  
return sSiteURL; 8w\ZY>d  
} wticA#mb  
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public void setSSiteURL(String value) 3qVDHDQ?ZV  
{ ?Mj@;O9>'  
sSiteURL = value; S uo  
} ^- H  
,+U,(P5>s  
d
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public String getSFilePath() )oCb9K:km  
{ 3j}@}2D  
return sFilePath; _I<LB0kgf.  
} FI=]K8  
wxW\L!@  
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public void setSFilePath(String value) Z%9_vpWc  
{ eW/sPQ-  
sFilePath = value; 4lsg%b6_%,  
} E%np-is{1  
K)_DaTmi)  
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public String getSFileName() >21f
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{ xwe^_7  
return sFileName; N799@:.  
} N[j*Q 8X_  
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public void setSFileName(String value) |4?O4QN
 
{ xu(N'l.7&  
sFileName = value; o3kVcX^  
} qpZR-O  
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public int getNSplitter() Ow f:Kife  
{ )a0%62  
return nSplitter; x2@W,?oPm  
} (n
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public void setNSplitter(int nCount) &vHfuM`  
{ '~;vp  
nSplitter = nCount; e%K oecq  
} ZgH(,g,TU  
} ~uRL+<.c  
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C)v*L#{%  
/* ML-?#jNa<  
**Utility.java de$0DfK  
*/ *@SZ0   
package NetFox; vAH`tPi>  
#!RO,{FT  
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public class Utility { Z`{ZV5  
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public Utility() d@IV@'Q7u  
{ rUOl+p_47  
~ u',Way  
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} H(,D5y`k1  
s?pd&_kOv3  
//线程睡眠 A[6D40o  
public static void sleep(int nSecond) 1$1[6 \3v  
{ E whCX'Vaj  
try{ Qqn9nO9  
Thread.sleep(nSecond); =}^J6+TVL  
} zEN3Nn.8  
catch(Exception e) y L|'K}  
{ |z%:{  
e.printStackTrace (); t~(|2nTO5  
} yK"T5^o  
} b<1+q{0r  
#cdrobJ  
//日志 6L4<c+v_  
public static void log(String sMsg) p81Vt  
{ `Eq~W@';Q0  
System.err.println(sMsg); /@qnEP%  
} =/zb$d cz  
wM aqR"%  
M*n@djL$\~  
public static void log(int sMsg) rwh,RI) )g  
{ hiBZZ+^[  
System.err.println(sMsg);  tQSJ"Q  
} 8AgKK=C=  
} Lw_s'QNWR  
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/* uS}qy-8J  
**TestMethod.java 7ea<2va,  
*/ %f'mW2  
package NetFox; p^>_VE[S  
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public class TestMethod { & cV$`L  
n4%ZR~9WH  
RF$2p4=[  
public TestMethod() <g3)!VR^q  
{ ///xx/weblogic60b2_win.exe tkjQSz  
try{ E8LA+dKN:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JVxGS{Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |fIIfYE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;%W]b  
fileFetch.start(); IMcuoQ5  
} '^10sf`"
 
catch(Exception e){e.printStackTrace ();} mi]bS  
]/ffA|"U`  
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} `G0GWh)`x  
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7H!/et?S,  
public static void main(String[] args) l.nd Wv  
{ w 8BSY  
new TestMethod(); {a9(
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} J1UG},-h  
} 9Rd&Jq^  
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