http断点续传简单实现（java)

/* ,Z_aZD4  
**SiteFileFetch.java `=}w(V8pc  
*/ p=fj1*  
package NetFox; O{P@fv%~(o  
import java.io.*; 1u9*)w  
import java.net.*; =x_~7 Xc{  
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 Rix|LKk{  
public class SiteFileFetch extends Thread { (SH<]@s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \E}YtN#  
long[] nStartPos; //开始位置 lMn1e6~K  
long[] nEndPos; //结束位置 F\K&$
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 6jDHA3  
long nFileLength; //文件长度 k'(d$;Jgr  
boolean bFirst = true; //是否第一次取文件 w# iezo. 0  
boolean bStop = false; //停止标志 V"A*k^}  
File tmpFile; //文件下载的临时信息 47/14rY 2  
DataOutputStream output; //输出到文件的输出流 +VE] .*T  
{/u}  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q;h6F{i  
public SiteFileFetch(SiteInfoBean bean) throws IOException vV
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{ }=7? & b  
siteInfoBean = bean; T
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SJ
 ay  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t_Q\uo}  
if(tmpFile.exists ()) G(Ky7SZ  
{ !0}SZ  
bFirst = false; %U<1
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read_nPos(); &/\Q6$a  
} l-mt{2  
else F{'lF^Dc  
{ NKX,[o1  
nStartPos = new long[bean.getNSplitter()]; be->ofUYgs  
nEndPos = new long[bean.getNSplitter()]; $FJf8u`  
} ]c
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} .)Wqo7/Gx  
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public void run() 3hD
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{ 9w"kxAN  
//获得文件长度 Cih~cwE  
//分割文件 ge[hAI2I  
//实例FileSplitterFetch 9f|+LN##  
//启动FileSplitterFetch线程 %fF0<c^-U  
//等待子线程返回 LBw$K0  
try{ }w|a^=HAp  
if(bFirst) DwNEqHi  
{ S.! n35  
nFileLength = getFileSize(); # fe%E.  
if(nFileLength == -1) ^U8^P]{R|  
{ Mhwuh`v%  
System.err.println("File Length is not known!"); 5ltrr(MeD  
} wk@S+Q  
else if(nFileLength == -2) 23iMG]J&  
{ q+J;^u"E  
System.err.println("File is not access!"); JtbwY@R  
} <rbzsn"a  
else \'>ZU-V  
{ @
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for(int i=0;i<nStartPos.length;i++) qOD:+b  
{ R2Y.s^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -~rZ| W~v  
} 5 A2u|UU  
for(int i=0;i<nEndPos.length-1;i++) sI OT6L^7  
{ X$0&tmum  
nEndPos = nStartPos[i+1]; [AA*B  
} i^Ip+J+[  
nEndPos[nEndPos.length-1] = nFileLength; kp=wz0#  
} ?]]7PEee*  
} 9e _8Z@|  
 Qk)E:  
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//启动子线程 ,| Zkpn8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |ZmWhkOX  
for(int i=0;i<nStartPos.length;i++) !zR1CM  
{ R[bI4|t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #*zl;h1(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b
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nStartPos,nEndPos,i); 9l&4mt;+&<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;3P~eeQR  
fileSplitterFetch.start(); SKdh!*G  
} c*N>7IF,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XPfheV G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ')82a49eA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J};=)xLX;  
nEndPos = " + nFileLength); Fs 95^T  
// fileSplitterFetch[nPos.length-1].start(); d#>iFD+  
(DTXc2)c  
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//等待子线程结束 lWRRB&8  
//int count = 0; p OO4fc  
//是否结束while循环  C4.g}q  
boolean breakWhile = false; sqE? U*8.-  
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while(!bStop) ~}@cSv'(1  
{ [:"7B&&A  
write_nPos(); S uo  
Utility.sleep(500); XR@C^d  
breakWhile = true; {IG5qi?/E)  
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for(int i=0;i<nStartPos.length;i++) (O`2$~mIM  
{ ZmKxs^5S  
if(!fileSplitterFetch.bDownOver) O
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{ '.5_
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breakWhile = false; 7dq*e4z)  
break; gQ;1SY!  
} v$]eCj'  
} 0NFYFd-50  
if(breakWhile) UgC{  
break; gBPYGci2F  
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//count++; 2J1YrHj3  
//if(count>4) /xh/M@G3  
// siteStop(); 1 [D,Mu%E  
} NB#-W4NA  
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System.err.println("文件下载结束！"); Dqg~g|(Q<  
} G\ m`{jv  
catch(Exception e){e.printStackTrace ();} i8+[-mh  
} tO8<N'TD  
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//获得文件长度 *)82iD  
public long getFileSize() >u/ T`$  
{ <xO" E%t  
int nFileLength = -1; N~0~1 WQn  
try{ N[j*Q 8X_  
URL url = new URL(siteInfoBean.getSSiteURL()); a%N
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pe@j`Sm:Ej  
httpConnection.setRequestProperty("User-Agent","NetFox"); G Z~W#*|V  
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int responseCode=httpConnection.getResponseCode(); 3 6-Sw  
if(responseCode>=400) Fo$'*(i  
{ d"~-D;  
processErrorCode(responseCode); {~a+dEz  
return -2; //-2 represent access is error 4O1[D?)`x  
} #*)X+*  
:}{,u6\  
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String sHeader; /AhN$)(
O  
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for(int i=1;;i++) T/Fj0'  
{ {6Qd,CX
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! 1wf/C;=  
//Utility.log(in.readLine()); I]vCra  
sHeader=httpConnection.getHeaderFieldKey(i); 0k):OVfm=  
if(sHeader!=null) :o=a@Rqx  
{ TW)~&;1
l  
if(sHeader.equals("Content-Length")) j _p|>f<}  
{ 2PVtyV3;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2|:xb9#  
break; e0cVg  
} T(4OPiKu  
} aA3KJa  
else C'oNGOEd  
break; ,3p$Z  
} #24eogo~  
} ;:#g\|(<+  
catch(IOException e){e.printStackTrace ();} % >
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catch(Exception e){e.printStackTrace ();} \$[; d:9j  
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Utility.log(nFileLength); TL*8h7.(  
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return nFileLength; 'pQ\BH  
} wD|I^y;  
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{- Y.C
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//保存下载信息（文件指针位置） o{I]c#W  
private void write_nPos() HI%#S&d  
{ VyWPg7}e  
try{ dSq3V#Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .Mz'h9@  
output.writeInt(nStartPos.length); Kh,zp{  
for(int i=0;i<nStartPos.length;i++) 1?hx/02  
{ -er8(snDQ  
// output.writeLong(nPos); Yj/[I\I"m  
output.writeLong(fileSplitterFetch.nStartPos); d@IV@'Q7u  
output.writeLong(fileSplitterFetch.nEndPos); 4y|%Oj  
} hQPNxpe  
output.close(); Ks_B%d  
} REc+@;B  
catch(IOException e){e.printStackTrace ();} A$;"9F@  
catch(Exception e){e.printStackTrace ();} F!pgec%]'  
} v>oWk:iJP  
6 ~LCj"  
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//读取保存的下载信息（文件指针位置） 7,:$, bL  
private void read_nPos() pxgVYr.  
{ NR|t~C+  
try{ O=2SDuBZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sBV})8]KM  
int nCount = input.readInt(); JrgpDZ  
nStartPos = new long[nCount]; @24)*d^1  
nEndPos = new long[nCount]; Ir\f_>7  
for(int i=0;i<nStartPos.length;i++) RhQ[hI  
{ P{ HYZg  
nStartPos = input.readLong(); [zMnlO  
nEndPos = input.readLong(); 1SO!a R#g  
} K]s*rPT/,  
input.close(); ,"U_oa3  
} oasEG6OI8  
catch(IOException e){e.printStackTrace ();} Eu)(@,]we  
catch(Exception e){e.printStackTrace ();} ?X5Y8n]y\h  
} }=T=Z#OgH  
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private void processErrorCode(int nErrorCode) nlsif  
{ )ZqY`by!  
System.err.println("Error Code : " + nErrorCode); gtVnn]Jh  
} 6tKCY(#oO+  
8{ooLdpX7  
6(as.U>K  
//停止文件下载 ?Ja&LNI9S  
public void siteStop() gSn9L)k(O  
{ =/zb$d cz  
bStop = true; &w"1VOV<  
for(int i=0;i<nStartPos.length;i++) lwj,8  
fileSplitterFetch.splitterStop(); 0<'Q;'2* L  
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} Vq>$ZlvS  
} I`-N]sf^  
//负责部分文件的抓取 '7;b+Vbl#  
**FileSplitterFetch.java ?Q
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*/ Q-7C'|  
package NetFox; j,@@[{tu  
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1  
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import java.io.*; Fh0cOp(  
import java.net.*; U\~9YX8  
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public class FileSplitterFetch extends Thread { 7 S6@[-E
 
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String sURL; //File URL /t"FZ#  
long nStartPos; //File Snippet Start Position ~8l(,N0  
long nEndPos; //File Snippet End Position vn"+x_  
int nThreadID; //Thread's ID p^>_VE[S  
boolean bDownOver = false; //Downing is over m?)REE  
boolean bStop = false; //Stop identical {>rGe#Vu  
FileAccessI fileAccessI = null; //File Access interface 6G0Y,B7&  
{$H-7-O$  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yDe6f(D  
{ r)xkpa5  
this.sURL = sURL; O~~
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this.nStartPos = nStart; RF$2p4=[  
this.nEndPos = nEnd; |X6/Y@N  
nThreadID = id; .,+TpPkc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %!X9>i>  
} 4M,Q{G
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public void run() 0tb%h[%,M  
{ +0Z,#b  
while(nStartPos < nEndPos && !bStop) |fIIfYE  
{ t]14bf$*Q  
IF~E;  
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try{ sDXD>upO  
URL url = new URL(sURL); vnr{Ek
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Q/t+  
httpConnection.setRequestProperty("User-Agent","NetFox"); x,81#=m^h  
String sProperty = "bytes="+nStartPos+"-"; ::`#qa4!  
httpConnection.setRequestProperty("RANGE",sProperty); $LkTu  
Utility.log(sProperty); K*id 1YY  
|^k&6QO5  
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InputStream input = httpConnection.getInputStream(); }"x#uG  
//logResponseHead(httpConnection); ]:_
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byte[] b = new byte[1024]; PXrv2q[5?  
int nRead; /9@[gv A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !> 2kH  
{ E>I\m!ue  
nStartPos += fileAccessI.write(b,0,nRead); 0*^>/*  
//if(nThreadID == 1) EJ@&vuDd$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J1UG},-h  
} -g\;B  
s{9G//  
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Utility.log("Thread " + nThreadID + " is over!"); >h3m/aeNC  
bDownOver = true; ZULnS*V;5  
//nPos = fileAccessI.write (b,0,nRead); iO@UzD#v  
} RzOcz=A}  
catch(Exception e){e.printStackTrace ();} tN1xZW:  
} fPBJ%SZ  
} Uu_Es{@  
!YVGT <  
-~] q?k?  
//打印回应的头信息 A~)#  
public void logResponseHead(HttpURLConnection con) AC&)FY
  
{ mxEniy  
for(int i=1;;i++) M~eXC  
{ aM7=>  
String header=con.getHeaderFieldKey(i); e%_J O7  
if(header!=null) AEd]nVV Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d+o.J",E  
Utility.log(header+" : "+con.getHeaderField(header)); {|{;:_.>  
else ;_p$5GVR|  
break; c4V%
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} iu.v8I;<  
} LE}V{%)xD  
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public void splitterStop() 8_Nyy/K#F  
{ wQ9?Z.-$  
bStop = true; SceK$  
} 363KU@`  
/*2)|2w  
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} ["^? vhv  
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=6'Fm$R  
/* yu>)[|-  
**FileAccess.java g{^~g  
*//文件访问(定位，写) `0, G'F  
package NetFox; WZM  
import java.io.*; =Hbf()cN)  
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> JC"YB  
public class FileAccessI implements Serializable{ hVIv->  
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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 !oa/\p  
RandomAccessFile oSavedFile; kvG.?^ v  
long nPos; -}u1ZEND  
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2]]}
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public FileAccessI() throws IOException ,N1pww?  
{ A0,h7<i  
this("",0); V|G*9^Y  
} ,T*\9'Q  
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public FileAccessI(String sName,long nPos) throws IOException M`n0 qy  
{ 2H1 [oD[  
oSavedFile = new RandomAccessFile(sName,"rw"); } m"':f  
this.nPos = nPos; @/,0()*dL  
oSavedFile.seek(nPos); {n&GZG"f  
} 85
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public synchronized int write(byte[] b,int nStart,int nLen) 7K ~)7U  
{ pk`5RDBu  
int n = -1; zm8k,e +5-  
try{ ;d<O/y,:4  
oSavedFile.write(b,nStart,nLen); 5=\^DeM@ H  
n = nLen; KZO[>qC"R  
} eLLOE)x  
catch(IOException e) ;l^'g}dQ^  
{ 4V c``Um  
e.printStackTrace (); hBaF^AWW  
} j\"d/{7Q  
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return n; 1BgHkDW  
} 3?D{iMRM  
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} 3x
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~^'WHuzPy  
/* <*+[E!oi  
**SiteInfoBean.java 3,EtyJ3[Bh  
*/ LcT;7yv  
package NetFox; 2I|lY>Z  
'y5H%I
!  
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public class SiteInfoBean { XD" 4t4~>  
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private String sSiteURL; //Site's URL ZuZCIqN  
private String sFilePath; //Saved File's Path D^a(|L3;  
private String sFileName; //Saved File's Name :wEy""*N0  
private int nSplitter; //Count of Splited Downloading File q&}+O  
i9V,  
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public SiteInfoBean() mN>(n+ly  
{//nSplitter的缺省值为5 Q+/P>5O/  
//default value of nSplitter is 5 x0%yz+i{:  
this("","","",5); $d,/(*Y#-  
} pFV~1W:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,B /b>i  
{ 8Q"1I7U  
sSiteURL= sURL; UkXa mGoy3  
sFilePath = sPath; ktRGl>J  
sFileName = sName; I0><IaFy  
this.nSplitter = nSpiltter; M`8c|*G   
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x8x-b>|$&<  
} 1|AY&u%fiP  
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:`lP+y?a1  
public String getSSiteURL() \j-:5M#m  
{ Sx (E'?]  
return sSiteURL; |qwx3 hQ?  
} f@$kK?c?  
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public void setSSiteURL(String value) m
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{ 6!USSipn  
sSiteURL = value; gzy|K%K  
} ]vPdj"7  
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public String getSFilePath() Gd'_X D  
{ Kr<UPr  
return sFilePath; us8HXvvp{  
} d{7)_Sbky  
0P!Fci/t  
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public void setSFilePath(String value) /{
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{ !N_eZPU.v  
sFilePath = value; rQ6>*0xL_  
} Pp_? z0M  
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rZ)7(0BBs  
public String getSFileName()
)D)4=LJ  
{ {t.S_|IE  
return sFileName; RTDplv; ]  
} A0,e3gb  
_ b</ ::Tp  
XX "3.zW  
public void setSFileName(String value) Sqyju3Yp  
{ Eau V
  
sFileName = value; +?[s"(  
} xP
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CN}0( 2n  
?A24h!7  
public int getNSplitter() F\GNLi  
{ -N6ek`  
return nSplitter; :XoR~syT  
} IS`ADDU[S  
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=P_*.SgR  
public void setNSplitter(int nCount) Sfp-ns32%A  
{ y+V>,W)r7  
nSplitter = nCount; _^ic@h3'X~  
} rY&#g%B6Fp  
} (ip3{d{CT]  
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3`RI[%AN~  
/* G )`gn  
**Utility.java 3+ 2&9mm  
*/ wehiX7y  
package NetFox; Ts|;5ya5m  
<OJqeUo+*\  
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public class Utility { }_mMQg2>=  
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L/%{,7l<^?  
public Utility() -^;,m=4{3  
{ Uz[#ye  
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} Bn=YGEvz  
?'"BX  
//线程睡眠 .3@Pz]\M#>  
public static void sleep(int nSecond) 4d}
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{ '<*%<J{(  
try{ :_nGh]%  
Thread.sleep(nSecond); ~"4Cz27  
} wuXH'  
catch(Exception e) %nE%^Enw  
{ <]|!quY<*  
e.printStackTrace (); fA[T5<66  
} :Z_abKt  
} '?fGI
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(v:8p!QN  
//日志 C7}iwklcsa  
public static void log(String sMsg) (?lT @RY/  
{ yJlRW!@&:  
System.err.println(sMsg); RyM29uD  
} '"ze Im~  
5B8fz;l= B  
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public static void log(int sMsg) P3Ah1X7W"C  
{ v |pHbX  
System.err.println(sMsg); aSJD'u4w.a  
} D$rn?@&g  
} /^I!)|At  
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/* F[F NtZ  
**TestMethod.java oR7f3';?6  
*/  Bs>S2]  
package NetFox; PlgpH'z4$  
5LU7}v~/  
sqjDh  
public class TestMethod { dldS7Q  
nLPd]%78>  
322-'S3<  
public TestMethod() w vI v+Q9  
{ ///xx/weblogic60b2_win.exe 1!E}A!;  
try{ ]=/?Ooh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tn(uH17  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /+. m.TF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0 N0< 4b  
fileFetch.start(); NqFfz9G)  
} v:>sS_^  
catch(Exception e){e.printStackTrace ();} J9y}rGO  
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} LcNI$g;}Yf  
R?N+./{  
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public static void main(String[] args) a"Ly9ovW  
{ O0bOv S  
new TestMethod(); ra_TN;(  
} <;jg/  
} t#-4edB,  
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