http断点续传简单实现（java)

/* q$Zh@  
**SiteFileFetch.java
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*/ KyYMfC  
package NetFox; gM u"2I5  
import java.io.*; t!W(_8j  
import java.net.*; CUBEW~X}M  
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public class SiteFileFetch extends Thread { e478U$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~obqG!2m  
long[] nStartPos; //开始位置 "$+Jnc!!  
long[] nEndPos; //结束位置 lm-dW'7&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |Mup8(gCk  
long nFileLength; //文件长度 [B#R94  
boolean bFirst = true; //是否第一次取文件 'MUv5Th  
boolean bStop = false; //停止标志 m.# VYN`+A  
File tmpFile; //文件下载的临时信息 bYpntV  
DataOutputStream output; //输出到文件的输出流 t^R][Ay&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'g=  
public SiteFileFetch(SiteInfoBean bean) throws IOException ODNM+#}`  
{ pN:Kdi  
siteInfoBean = bean; bpJ(XN}E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [q
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ln')QN  
if(tmpFile.exists ()) t{^*6XOcJ  
{ |ef7bKU8  
bFirst = false; eTI%^d|  
read_nPos(); [!HEQ8 2g  
} \r^qL^  
else }Gz~nf%  
{ B}Z63|/N  
nStartPos = new long[bean.getNSplitter()]; A}G7l?V&  
nEndPos = new long[bean.getNSplitter()]; dMf:h"7  
}
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} Vd,jlt.t  
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public void run() +%T\`6  
{ 8=B|C'>  
//获得文件长度 `#F{Waww'  
//分割文件 Neq+16*u  
//实例FileSplitterFetch TJ_$vI  
//启动FileSplitterFetch线程 X^}I-M%{m  
//等待子线程返回 ,<n}W
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try{ bH7X'%r  
if(bFirst) jVv0ST*z  
{ ieDk;  
nFileLength = getFileSize(); m[?E  
if(nFileLength == -1) |oH,   
{ #%
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System.err.println("File Length is not known!"); N..yQ-6x?  
} &zl|87M  
else if(nFileLength == -2) 5{|7$VqPF  
{ gf#{k2r  
System.err.println("File is not access!"); BgurzS4-  
} dA@]!  
else `18qbot  
{ [;4g  
for(int i=0;i<nStartPos.length;i++) m,*QP*  
{ nt 81Bk=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?*[N_'2W+  
} NPhhD&W_  
for(int i=0;i<nEndPos.length-1;i++) eJF5n#  
{ 8p^bD}lN7  
nEndPos = nStartPos[i+1]; cv-PRH#  
} ?]|\4]zV  
nEndPos[nEndPos.length-1] = nFileLength; {@H6HqD  
} yzbx .  
} CJ/X}hi,  
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9_
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//启动子线程 7`-Zuf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; J`peX0Stl  
for(int i=0;i<nStartPos.length;i++) %+@O#P  
{ ypbe!Y<i]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m!|kW{B#A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nW PF6V>  
nStartPos,nEndPos,i); _GXk0Ia3`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j~2{lCT  
fileSplitterFetch.start(); 5gb|w\N>  
} v~f HYa>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YZLkL26[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .f*4T4eR-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _Z
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nEndPos = " + nFileLength); n
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// fileSplitterFetch[nPos.length-1].start(); 1t:Q_j0Ym  
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*;l]8.  
//等待子线程结束 H7z,j}l  
//int count = 0; <":;+Ng+  
//是否结束while循环 dbwe?ksh  
boolean breakWhile = false; :8L8q<U  
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while(!bStop) ?x$
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{ i2@VB6]?  
write_nPos(); }\
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Utility.sleep(500); nGpXI\K  
breakWhile = true; T}Km?d  
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for(int i=0;i<nStartPos.length;i++) ZOft.P O  
{ sd,J3  
if(!fileSplitterFetch.bDownOver) $h2){*5E{  
{ `>gd&u  
breakWhile = false; K$&s=Hm  
break; k52/w)Ro,$  
} zcel|oz)  
} NaPt"G  
if(breakWhile) ;9[fonk  
break; <LmIK  
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//count++; Uddr~2%(  
//if(count>4) q4R5<LW"  
// siteStop(); VvvRRP^q  
} 4E;VM{  
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System.err.println("文件下载结束！"); qIVx9jNN  
} -l`f)0{  
catch(Exception e){e.printStackTrace ();} %b%-Ogz;4  
} vL|SY_:4  
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//获得文件长度 TlXI|3Ip  
public long getFileSize() =+/
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{ &Lt}=3G  
int nFileLength = -1; =@m &s^R  
try{ j.C`U(n}`  
URL url = new URL(siteInfoBean.getSSiteURL()); :9O#ObFR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iWRH{mK  
httpConnection.setRequestProperty("User-Agent","NetFox"); $h5xH9x ;  
I CZ4A{I  
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int responseCode=httpConnection.getResponseCode(); qS403+Su1=  
if(responseCode>=400) dq7x3v^"ZG  
{ yL%K4$z  
processErrorCode(responseCode); y-T| #  
return -2; //-2 represent access is error NhfJ30~  
} rx $mk  
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String sHeader; O*eby*%h  
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for(int i=1;;i++) "JVkVp[5D+  
{ ks3`3q 7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?i)f^O  
//Utility.log(in.readLine()); l,R/Gl  
sHeader=httpConnection.getHeaderFieldKey(i); 0)%YNaskj  
if(sHeader!=null) P<PJ)>  
{ Ager$uC  
if(sHeader.equals("Content-Length")) E4gYemuN  
{ ~Fe${2
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )i~cr2Hk  
break; +1Vjw'P  
} CAWA3fcQp  
} *meZ8DV2DH  
else c;%_EN%  
break; `sUZuWL_  
} 7Ilm{@b=  
} 3Vsc 9B"w  
catch(IOException e){e.printStackTrace ();} #hW;Ju73  
catch(Exception e){e.printStackTrace ();} nIAx2dh?  
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Utility.log(nFileLength); 6Se?sHC>  
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return nFileLength; _]04lGx27  
} Mx6@$tQ%  
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//保存下载信息（文件指针位置） ;6gDV`Twy  
private void write_nPos() 5j:0Yt  
{ w<C#Bka  
try{ h"Xg;(K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W@T~ly;e*  
output.writeInt(nStartPos.length); 9!f/aI  
for(int i=0;i<nStartPos.length;i++) $iI]MV%
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{ QBtnx[  
// output.writeLong(nPos); #%`|~%`{:  
output.writeLong(fileSplitterFetch.nStartPos); unshH<  
output.writeLong(fileSplitterFetch.nEndPos); FjK3 .>'  
} 0T@Zb={  
output.close(); [r3!\HI7x  
} D5$wTI  
catch(IOException e){e.printStackTrace ();} Q<z_/j9  
catch(Exception e){e.printStackTrace ();} 5 elw~u  
} E_Im^a  
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//读取保存的下载信息（文件指针位置） @WJgWJm  
private void read_nPos() /nyUG^5#{  
{ /4tj3B,  
try{ uJOJ-5}yt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (H)2s Y  
int nCount = input.readInt(); 0rh]]kj  
nStartPos = new long[nCount]; |w_7_J2
 
nEndPos = new long[nCount]; x6(~;J  
for(int i=0;i<nStartPos.length;i++) t]>Lh>G  
{ L/wD7/ODr  
nStartPos = input.readLong(); e@c0WlWa  
nEndPos = input.readLong(); \x)n>{3C  
} c#a@n 4  
input.close(); M54j@_81pX  
} H:!7:  
catch(IOException e){e.printStackTrace ();} ;ToKJ6hN|*  
catch(Exception e){e.printStackTrace ();} HuB<k3#sPy  
} 0%,!jW{`  
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private void processErrorCode(int nErrorCode) Tg!i%v(-t  
{ xG}(5Tt  
System.err.println("Error Code : " + nErrorCode); !O-T0O   
} I'PeN0T f  
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//停止文件下载 UjaK&K+M?  
public void siteStop() 6Pnk5ps }h  
{ =jSb'Vu|  
bStop = true; =jlt5 z  
for(int i=0;i<nStartPos.length;i++) ]x\-$~E  
fileSplitterFetch.splitterStop(); eK.e|z|  
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} cj+ FRG~u  
} i%ZW3MrY~  
//负责部分文件的抓取 9&upujVS  
**FileSplitterFetch.java iOwx0GD.n  
*/ n.wF&f'D]  
package NetFox; HOw-]JSP2  
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import java.io.*; q2. XoCf  
import java.net.*; ?z}=B  
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public class FileSplitterFetch extends Thread { ELBa}h;  
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String sURL; //File URL , FhekaA  
long nStartPos; //File Snippet Start Position '6Ay&A3N]  
long nEndPos; //File Snippet End Position {S,l_d+(  
int nThreadID; //Thread's ID qP{/[uj[K  
boolean bDownOver = false; //Downing is over 7nHF@Y|*"  
boolean bStop = false; //Stop identical hJwC~HG5  
FileAccessI fileAccessI = null; //File Access interface D
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cs T2B[f9D  
{  $rz=6h  
this.sURL = sURL; ^\\Tx*#i  
this.nStartPos = nStart; GKvN* SU=  
this.nEndPos = nEnd; @kk4]:,w  
nThreadID = id;  -QOw8vm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {LX.iH9}l  
} VUVaaOm
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public void run() `VKf3&|<A  
{ ,Vh.T&X5  
while(nStartPos < nEndPos && !bStop) bA\<.d  
{ (WK
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try{ Vl_:c75"  
URL url = new URL(sURL); vJ\pR~?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4AG\[f 8q  
httpConnection.setRequestProperty("User-Agent","NetFox"); 43={Xy   
String sProperty = "bytes="+nStartPos+"-"; .u:81I=w(  
httpConnection.setRequestProperty("RANGE",sProperty); r) $+  
Utility.log(sProperty); *NkA8PC  
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InputStream input = httpConnection.getInputStream(); SG
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//logResponseHead(httpConnection); }:u~K;O87  
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byte[] b = new byte[1024]; \"CZI<=TB  
int nRead; v-yde>(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _@ *+~9%8p  
{ wNQ*t-K  
nStartPos += fileAccessI.write(b,0,nRead); }b=}uiR#  
//if(nThreadID == 1) XK|R8rhg8`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); si&S%4(  
} f 1w~!O9  
 emK$`9  
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Utility.log("Thread " + nThreadID + " is over!"); kGdt1N[  
bDownOver = true; 66.5QD0  
//nPos = fileAccessI.write (b,0,nRead); JNkwEZhHyg  
} K$M^gh0  
catch(Exception e){e.printStackTrace ();} qw@puw@D  
} UNPezHaz  
} 2zVJ
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1AG=%F|.  
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//打印回应的头信息 AZa6Cw  
public void logResponseHead(HttpURLConnection con) Kv.>Vf.T}_  
{ .so[I
 
for(int i=1;;i++) jy giG&H  
{ Qtbbb3m;  
String header=con.getHeaderFieldKey(i); Ku\Y'ub  
if(header!=null) 0A,]$Fzt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +n<k)E@>J  
Utility.log(header+" : "+con.getHeaderField(header)); ]%BWIqbr  
else dxZ
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break; S,<EEtXQ  
} )RO<o O  
} ^ <Pq,u%k  
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public void splitterStop() L=q+|j1>  
{ p98~&
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bStop = true; $BFvF ,n  
} ?t+5s]  
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} 6B@CurgB  
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/* Zs}5Smjl;%  
**FileAccess.java SB5&A_tr  
*//文件访问(定位，写) td4[[ /  
package NetFox; abJ" [  
import java.io.*; AJSx%?h:6  
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public class FileAccessI implements Serializable{ 1gmt2>#v%  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x_c7R;C  
RandomAccessFile oSavedFile; %I-+Ead0i  
long nPos; F B?UZ  
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public FileAccessI() throws IOException 8F:e|\SB#  
{ HcedE3Rg  
this("",0); ]S(%[|  
} 6I!7c^]t  
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public FileAccessI(String sName,long nPos) throws IOException KN?6;G{  
{ ;zYqsS  
oSavedFile = new RandomAccessFile(sName,"rw"); LwhyE:1  
this.nPos = nPos; )13dn]o=2  
oSavedFile.seek(nPos); DK=cVpN%s  
} .\8X[%K9nc  
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public synchronized int write(byte[] b,int nStart,int nLen) Pfm_@'8  
{ ^Ve<>b  
int n = -1; esHQoIhd  
try{ ?{U m  
oSavedFile.write(b,nStart,nLen); 0H0-U'l  
n = nLen; Gg~QAsks   
} >[Ye  
catch(IOException e) &BtK($  
{ N.
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e.printStackTrace (); vjQb%/LWl  
} ?Q-h n:F)  
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return n; m!W3Cwz\&  
} PH*\AZJCl  
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} lj{VL}R  
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/* "H&"(=  
**SiteInfoBean.java j:}DBk  
*/ t\RF=BbJJ  
package NetFox; B%KG3]  
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public class SiteInfoBean { kl
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@JvPx0  
private String sSiteURL; //Site's URL @h*fFiY&{  
private String sFilePath; //Saved File's Path HLBkR>e  
private String sFileName; //Saved File's Name ?%VI{[y#>  
private int nSplitter; //Count of Splited Downloading File Ov#=]t5  
I+!:K|^
  
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public SiteInfoBean() >yXN,5d[  
{//nSplitter的缺省值为5 2P]L9'N{Y  
//default value of nSplitter is 5 CH fVQ|!\  
this("","","",5); :>aQ~1f>]  
} #-8\JEn  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gJ;_$`  
{ L:(1ZS  
sSiteURL= sURL; .<z!3O&L  
sFilePath = sPath; dgDy5{_  
sFileName = sName; xl"HotsX-x  
this.nSplitter = nSpiltter; (YY~{W$w(  
>(y<0   
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} >Bs#Xb_B]  
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public String getSSiteURL() G[8in  
{  49d@!  
return sSiteURL; K_ lVISBQ  
} LGc&o]k  
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public void setSSiteURL(String value) _BFOc>0  
{ Dw7vv]+ S  
sSiteURL = value; yQ3OL#  
} &QG6!`fK}3  
VdP`a(Yd;  
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public String getSFilePath() 6YuY|JD  
{ l<Q>N|1#k%  
return sFilePath; |oub!fG4  
} d*oUf
iW  
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public void setSFilePath(String value) a=XW[TY1  
{ hk/! 'd  
sFilePath = value; 1xU3#b&2tC  
} 6{,HiY  
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public String getSFileName() vA)O{W\o  
{ k8,?hX:  
return sFileName; s/:Fwr4q#a  
} p'sc0@}_O  
@$"L:1_  
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public void setSFileName(String value)
v|ox!0:#  
{ ;f,c't@w  
sFileName = value; JbO ~n )%x  
} ]#/4Y_d  
}tPk@$  
m^_6:Q0F!8  
public int getNSplitter() '!P"xBVAu  
{ YUQtMf9  
return nSplitter; mR8W]'gl.L  
} N$TL;T>  
;pD)m/$h`  
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public void setNSplitter(int nCount) s4%(>Q  
{ rdnRBFt  
nSplitter = nCount; CSV;+,Vv  
} +,50qN:%[  
} {B*W\[ns  
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/* F?m?UQS'u  
**Utility.java zq1mmFIO  
*/ hh~n#7w~IR  
package NetFox; FuX 8v  
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public class Utility { ;NV'W]  
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public Utility() *2}O-e  
{ ;eigOU]  
|3K)$.6~  
.$", *d  
} x'Pi5NRE  
JaWv]@9*  
//线程睡眠 hJ5z/5aE;  
public static void sleep(int nSecond) 3`HnLD/  
{ w(1Gi$Z(Q)  
try{ p.fF}B  
Thread.sleep(nSecond); ED$DSz)x  
} ;Qi }{;+  
catch(Exception e) ~#}Dx :HH  
{ <DH*~tLp2  
e.printStackTrace (); i`)!X:
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} tvX>{-
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} Fv?=Z-wk  
[oc~iDx%W  
//日志 <B /5J:o<  
public static void log(String sMsg) # x>ga  
{ Rq~t4sA:  
System.err.println(sMsg); xx*2?i  
} 4z:#I;  
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6@tvRDeaDW  
public static void log(int sMsg) Ni*Wz*o  
{ .BO<  
System.err.println(sMsg); 4c~>ci,N?(  
} IGFGa@C  
} !C:rb  
:f'&z47  
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/* kE;O7sN   
**TestMethod.java ID1?PM  
*/ vMSW$Bx ;  
package NetFox; K:yr-#(P/  
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public class TestMethod { (I{ $kB"p  
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,6
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public TestMethod() (}!C4S3#  
{ ///xx/weblogic60b2_win.exe (#(Or  
try{ lS{r=y_0.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kv
sA]tK.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v7trr W}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {bF1\S]2  
fileFetch.start(); 0)uYizJce  
} }xn_
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catch(Exception e){e.printStackTrace ();} vxN0,l  
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} K2'O]#  
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public static void main(String[] args) PfW|77  
{ S+x_c4 T  
new TestMethod(); <o:@dS  
} [JTto!Ih$  
} U;xF#e  
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