http断点续传简单实现（java)

/* X
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**SiteFileFetch.java OYd !v`<  
*/ TNth  
package NetFox; ..qCPlK;  
import java.io.*; YMgNzu  
import java.net.*; G?ZXWu.  
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public class SiteFileFetch extends Thread { uS-|wYE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "#]$r  
long[] nStartPos; //开始位置 :0ep(<|;  
long[] nEndPos; //结束位置 +H.`MZ=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]A"h&`Cvt  
long nFileLength; //文件长度 ;]iRk  
boolean bFirst = true; //是否第一次取文件 -%~4W?  
boolean bStop = false; //停止标志 M{\I8oOg  
File tmpFile; //文件下载的临时信息 q@&6#B  
DataOutputStream output; //输出到文件的输出流 J1vR5wbu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R2;  
public SiteFileFetch(SiteInfoBean bean) throws IOException rZF*q2?  
{ y^k$Us  
siteInfoBean = bean; KP"+e:a%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Rv=YFo[B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vj-h;rB0z  
if(tmpFile.exists ()) Th%zn2R B  
{ >V937  
bFirst = false; yuVs YV@"  
read_nPos(); GmG5[?)  
} U(Zq= M  
else 9z0p5)]n>  
{ Z.WW(C.  
nStartPos = new long[bean.getNSplitter()]; S 5U;#H  
nEndPos = new long[bean.getNSplitter()]; _&x%^&{  
} C}X\|J  
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} C+]I@Go'Tk  
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public void run() So;<6~  
{ .6> w'F{>  
//获得文件长度 R/_&m$ZB  
//分割文件 %C0Dw\A*:  
//实例FileSplitterFetch B[}6-2<>?C  
//启动FileSplitterFetch线程 H.;Q+A,8^  
//等待子线程返回 \!(zrfP
{(  
try{ ZC?Xqp  
if(bFirst) LscGTs,  
{ GB^Br6  
nFileLength = getFileSize(); 9$Y=orpWxr  
if(nFileLength == -1) 83m3OD_y  
{ ~>G^=0LT  
System.err.println("File Length is not known!"); pdMc}=K  
} [?gP;,  
else if(nFileLength == -2) RNL9>7xV  
{ D=$)n_F  
System.err.println("File is not access!"); #z(]xI)"  
} xoL\us`A  
else +mPx8P&%  
{ -/4P3SG/
 
for(int i=0;i<nStartPos.length;i++) Kq!3wb;  
{ }b}m3i1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jCY%|  
} :]"V-1#}  
for(int i=0;i<nEndPos.length-1;i++) gIfh3D=yX  
{ uO**E-`  
nEndPos = nStartPos[i+1]; DH=hH&[e(d  
} FwK]$4*  
nEndPos[nEndPos.length-1] = nFileLength; NHt\ U9l'  
} rjP/l6 ~'  
} f^e)O$N9]  
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//启动子线程 QPx^_jA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t-AmX)$  
for(int i=0;i<nStartPos.length;i++) rOYx b }1  
{ m~|40)   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;"I^ZFYX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cNrg#Asen&  
nStartPos,nEndPos,i); /QQ*8o8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pCDmXB  
fileSplitterFetch.start(); @W<m4fi  
} ^OdP4m( >>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }vuARZ>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K"6vXv4QO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iscz}E,Y  
nEndPos = " + nFileLength); #Z#-Ht  
// fileSplitterFetch[nPos.length-1].start(); X2_=agEP  

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//等待子线程结束 Iv *<La  
//int count = 0; \['Cj*ek  
//是否结束while循环 /FII07V  
boolean breakWhile = false; :s,Z<^5a)g  
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while(!bStop) zA 3_Lx!  
{ kM6 Qp  
write_nPos(); NbobliC=  
Utility.sleep(500); e.>P8C<&  
breakWhile = true; #E[0ys1O  
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for(int i=0;i<nStartPos.length;i++) .`lCWeHN  
{ 6863xOv{T  
if(!fileSplitterFetch.bDownOver) 1oS/`)  
{ h8P)%p  
breakWhile = false; M}a6Vu9  
break; 3]>| i  
} 0sqFF[i  
} >z03{=sAN  
if(breakWhile) ]]mJ']l  
break; qM`}{ /i  
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//count++; QZs!{sZ  
//if(count>4) 4Ig;3 ^%71  
// siteStop(); 7/H)Az@i45  
} uH]OEz\H'  
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System.err.println("文件下载结束！"); Wzh
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} 1x)J[fyId  
catch(Exception e){e.printStackTrace ();} sx%[=g+<2(  
} D-c4EV  
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//获得文件长度 xAr\gu  
public long getFileSize() 8mMQ[#0:}  
{ Ulyue  
int nFileLength = -1; =&]L00u.  
try{ ^c<Ve'-
 
URL url = new URL(siteInfoBean.getSSiteURL()); 2HdC |$_+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /(cPfZZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); !Ee:o"jG{  
A<{{iBEI`  
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int responseCode=httpConnection.getResponseCode(); ?}0,o.  
if(responseCode>=400) |N2#I
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{ Za9qjBH   
processErrorCode(responseCode); tYS06P^<  
return -2; //-2 represent access is error KHme&yMq  
} ]`K2N  
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String sHeader; m@c)Xci  
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for(int i=1;;i++) %Zi} MPx  
{ $I
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nKY6[|!#  
//Utility.log(in.readLine()); xEI%D|)<  
sHeader=httpConnection.getHeaderFieldKey(i); fex@,I&  
if(sHeader!=null) 3n _htgcv  
{ siI;"?  
if(sHeader.equals("Content-Length")) {.yB'.k?  
{ {mg2pfhB!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M >u_4AY  
break; QV!up^Zso  
} 2ESo2  
} >A= f1DF  
else r;{.%s7  
break; aOp\91  
} #mF"1QW  
} K-4PI+qQ\  
catch(IOException e){e.printStackTrace ();} _b 0&!l<  
catch(Exception e){e.printStackTrace ();} n S=W1zf  
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Utility.log(nFileLength); Da|z"I x  
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return nFileLength; d0D]Q  
} ^!d3=}:
0  
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//保存下载信息（文件指针位置） Ac@VGT:9  
private void write_nPos() *w&e\i|7  
{ x:Y1P:  
try{ 4dlGxat  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9w"*y#_  
output.writeInt(nStartPos.length); *wearCPeJ  
for(int i=0;i<nStartPos.length;i++) dN q$}  
{ h{Y",7]!  
// output.writeLong(nPos); N7"W{"3D  
output.writeLong(fileSplitterFetch.nStartPos); gdc<ZYcM  
output.writeLong(fileSplitterFetch.nEndPos); 7#Ft|5$~q  
} tw;}jh  
output.close();
1Mzmg[L8  
} 'L'R9&o<X  
catch(IOException e){e.printStackTrace ();} 5! {D!  
catch(Exception e){e.printStackTrace ();} dd;~K&_Q/i  
} ?9/G[[(  
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//读取保存的下载信息（文件指针位置） th_oJcS  
private void read_nPos() sC'`~}C  
{ jA1+x:Wq  
try{ -n 1v3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P:c w|Q  
int nCount = input.readInt(); M3\AY30L  
nStartPos = new long[nCount]; 54T`OE =  
nEndPos = new long[nCount]; iS^QTuk3%  
for(int i=0;i<nStartPos.length;i++) uRvP hkqm  
{ ,+k\p5P  
nStartPos = input.readLong(); [y(MCf19  
nEndPos = input.readLong(); )nkY_'BV  
} 4(+PD&_J  
input.close(); y(#e}z:  
} Et$2Y-L.  
catch(IOException e){e.printStackTrace ();} ^8WRqQdx  
catch(Exception e){e.printStackTrace ();} t.<i:#rj>l  
} 4?kcv59  
^#pEPVkY  
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private void processErrorCode(int nErrorCode) XFl6M~ c  
{ }bxs]?OW>  
System.err.println("Error Code : " + nErrorCode); c 9Mz]1@f  
} {: /}NpA$  
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//停止文件下载 Dt@SqX:~Ee  
public void siteStop() Nn6%9PX_)  
{ kiEa<-]  
bStop = true; w)f#V s  
for(int i=0;i<nStartPos.length;i++) 2y4bwi  
fileSplitterFetch.splitterStop(); *dQSw)R  
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} z{ dEC %  
} &C}*w2]0S  
//负责部分文件的抓取 =_CzH(=f#  
**FileSplitterFetch.java 3o*YzwRt  
*/ -).C  
package NetFox; )0
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import java.io.*; &oNAv-m^GD  
import java.net.*; Rq-ZL{LR7  
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public class FileSplitterFetch extends Thread {  mh%VrAq  
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String sURL; //File URL KI.unP%  
long nStartPos; //File Snippet Start Position *. t^MP  
long nEndPos; //File Snippet End Position NEs:},)o  
int nThreadID; //Thread's ID l
1I#QB@5n  
boolean bDownOver = false; //Downing is over WJi]t93  
boolean bStop = false; //Stop identical kh<2BOV  
FileAccessI fileAccessI = null; //File Access interface I%):1\)  
4euO1=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vN $s|R'@  
{  7GGUV  
this.sURL = sURL; (Ldi|jL  
this.nStartPos = nStart; I
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this.nEndPos = nEnd; )J |6-C  
nThreadID = id; TeQV?ZQ#}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xdPx{"C 3  
} DU^loB+  
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public void run() _1^'(5f$  
{ u*R_\*j@  
while(nStartPos < nEndPos && !bStop) c-w)|-ac.  
{ z:O8Ls^\T  
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}H2R3icE  
try{ qs6aB0ln  
URL url = new URL(sURL); iZ%yd-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %<5'=t'|-U  
httpConnection.setRequestProperty("User-Agent","NetFox"); |Tw~@kT@  
String sProperty = "bytes="+nStartPos+"-"; xw%0>K[  
httpConnection.setRequestProperty("RANGE",sProperty); 7)m9"InDI  
Utility.log(sProperty); 1C.VnzRnJ  
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InputStream input = httpConnection.getInputStream(); Bvj0^fSm  
//logResponseHead(httpConnection); #ob/p#k  
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}]TxlSp!;  
byte[] b = new byte[1024]; I fir ,8  
int nRead; INf&4!&h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =Qq+4F)MD  
{ =a!=2VN9y  
nStartPos += fileAccessI.write(b,0,nRead); & kIFcd@  
//if(nThreadID == 1) :&Nbw  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^Cmyx
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} $>gFf}#C  
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Utility.log("Thread " + nThreadID + " is over!"); POW>~Tof1  
bDownOver = true; QJNFA}*>  
//nPos = fileAccessI.write (b,0,nRead); mOSv9w#,  
} 4Hg9N}  
catch(Exception e){e.printStackTrace ();} X]=t>
 
} ;<5q]/IHK  
} R]dg_Da  
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//打印回应的头信息 0YzpZW"+  
public void logResponseHead(HttpURLConnection con) fM}#ON>Z  
{ +p^u^a  
for(int i=1;;i++) v=k$A  
{ $M#>9QHhc  
String header=con.getHeaderFieldKey(i); b
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if(header!=null) !wNO8;(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l2d{ 73h  
Utility.log(header+" : "+con.getHeaderField(header)); ToQ"Iy?  
else u-TUuP  
break; wzaV;ac4K  
} j|n R"!  
} E4!Fupkpf  
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public void splitterStop() *
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-  
{ X8|EHb<  
bStop = true; +V+a4lU14  
} z2c6T.1M  
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} -N@|QK>  
]9XDS[<2`  
_
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/* VX/#1StC  
**FileAccess.java r/sNrB1U"y  
*//文件访问(定位，写) 7KPwQ?SjT  
package NetFox; 9cgUT@a  
import java.io.*; {[(h[MW#  
s(^mZ -i  
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public class FileAccessI implements Serializable{ $|@ r!/W  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]{kPrey  
RandomAccessFile oSavedFile; i&k7-<  
long nPos; \f)#>+X-  
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r
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public FileAccessI() throws IOException Mq8L0%j  
{ B;WCTMy}  
this("",0); , dp0;nkr  
} ap~^Ty<>  
|%v^W3  
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public FileAccessI(String sName,long nPos) throws IOException b[7]F  
{ 1U\z5$V  
oSavedFile = new RandomAccessFile(sName,"rw"); &[SC|=U'M  
this.nPos = nPos; Kg$Mx  
oSavedFile.seek(nPos); o14cwb  
} fAmz4  
pNIf=lA  
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public synchronized int write(byte[] b,int nStart,int nLen) d[35d J7F  
{ 05k0n E  
int n = -1; n(|^SH4$b  
try{ L6LZC2N+2  
oSavedFile.write(b,nStart,nLen); v}x&?fU `  
n = nLen; LK"69Qx?5q  
} 7)k\{&+P  
catch(IOException e) 1QJL .  
{ gdoLyxQ  
e.printStackTrace (); ]tDDq=+v  
} HKr Mim-  
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{_Gs*<.  
return n; hzRYec(  
} Gbw2E&a  
$\! 7 {6a  
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} J")#I91  
 ][]  
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/* ##o#eZq:"  
**SiteInfoBean.java ow#1="G,=  
*/ 42{:G8  
package NetFox; ; Hd7*`$  
,1##p77.  
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public class SiteInfoBean { +@:x!q|^  
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private String sSiteURL; //Site's URL 3{h_&Gbo'D  
private String sFilePath; //Saved File's Path !L8#@BjU  
private String sFileName; //Saved File's Name 2"S}bfrX  
private int nSplitter; //Count of Splited Downloading File N&V`K0FU  
g>9kXP+  
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public SiteInfoBean() w'3iY,_ufC  
{//nSplitter的缺省值为5 -S+zmo8  
//default value of nSplitter is 5 {u9}bx'<  
this("","","",5); D1mfm.9_r^  
} 2T TdH)  
BRYHX.}h\A  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Rx|;=-8zg  
{ *cnNuT  
sSiteURL= sURL; {91nL'-'  
sFilePath = sPath; kE(mVyLQ  
sFileName = sName; 0<B$#8  
this.nSplitter = nSpiltter; tdaL/rRe  
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e NafpK  
} $DUZ!zaH!  
s|B3~Q]  
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public String getSSiteURL() &(mR> mT  
{ -FCe:iY! A  
return sSiteURL; \_6/vZ%-B  
} -7(@1@1  
I,'
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public void setSSiteURL(String value) UEVG0q
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{ 63~ E#Dt4  
sSiteURL = value; 9?3&?i2-  
} <V6VMYXY4  
wsVV$I[2
 
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public String getSFilePath() Ji 0 tQV  
{ F
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return sFilePath; 1~QPG\cdIX  
} .q3/_*  
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public void setSFilePath(String value) 7 ^mL_SMj  
{ FtC^5{V+V  
sFilePath = value; g2/8~cn8z  
} {T Ug.%u  
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public String getSFileName() &q|K!5[k  
{ }XM(:|8J,  
return sFileName; x7x\Y(@  
} 'anG:=  
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public void setSFileName(String value) r_;N
t  
{ =6|&Jt  
sFileName = value; g^ i&gNDx  
} ; p{[1  
 xLZG:^(I  
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public int getNSplitter() _M5|Y@XN-  
{ 3K/MvNI>  
return nSplitter; ^_5r<{7/ :  
} gH3vk $WS  
{LQ#y/H?  
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public void setNSplitter(int nCount) usL* x
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{ f[^Aw(o  
nSplitter = nCount; 84pFc;<  
} 2oRg 2R}  
} B\:%ufd ~  
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/* ""QP%  
**Utility.java 'xg Lt(  
*/ :e%Pvk  
package NetFox; 1!T1Y,w  
=-lb)Z"d  
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public class Utility { P0PWJ^+,+  
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public Utility() tWa)_y  
{ :s6o"VkW  
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} EJ:%}HhA  
nl,uuc*;  
//线程睡眠 s)Cjc.Qs  
public static void sleep(int nSecond) BC<^a )D=  
{ |(L
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try{ qF-@V25P  
Thread.sleep(nSecond); VsE9H]v   
}
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catch(Exception e) 25[I=ZdS  
{ rOOT8nkR#  
e.printStackTrace (); }\:NuTf  
} "#oHYz3D  
} bPt!
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:'l^kSP_*C  
//日志 C-MjJ6D<  
public static void log(String sMsg) doy`C)xI  
{ scou%K  
System.err.println(sMsg); TS9|a{j3!  
} ^y1j.M@q  
c>Xs&_  
C$D-Pt"+  
public static void log(int sMsg) es&vMY  
{ c>RFdc:U  
System.err.println(sMsg); ZR?yDgL  
} )PuFuf(wz  
} kB|B  
 &NK,VB;  
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/* &*G#H~\  
**TestMethod.java >kp?vK;'B  
*/ Y M\ K%rk  
package NetFox; zhRB,1iG  
8a'.ZdqC?  
( _)jkI \  
public class TestMethod { ^o1*a&~J@  
@u]rWVy;\[  
\$e)*9)  
public TestMethod() a\E:sPM'>  
{ ///xx/weblogic60b2_win.exe |>27B  
try{ Z}l3l`h!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 
$?<Z!*x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D\sWZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V(6Z3g  
fileFetch.start(); /1Q(b  
} \6<=$vD  
catch(Exception e){e.printStackTrace ();} #( jw!d&  
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} !0@Yplj  
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public static void main(String[] args) 4?7W+/~<&  
{ ytoo~n  
new TestMethod(); ,Pjew%  
} *q".-u!D[  
} <|+Ex  
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