http断点续传简单实现（java)

/* (9''MlGd%  
**SiteFileFetch.java DU0zez I9  
*/ }|0^EWL  
package NetFox; 2J7:\pR^  
import java.io.*; d[@X%  
import java.net.*; {j.bC@hWw  
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public class SiteFileFetch extends Thread { *v;2PP[^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9&-dTayIz  
long[] nStartPos; //开始位置 Sq>dt[7  
long[] nEndPos; //结束位置 DrKP%BnS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "%`1]Fr  
long nFileLength; //文件长度 dU&a{$ku[  
boolean bFirst = true; //是否第一次取文件 <Th6r.#?  
boolean bStop = false; //停止标志 yZ0-wI  
File tmpFile; //文件下载的临时信息 g!g#]9j  
DataOutputStream output; //输出到文件的输出流 ,?J!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?&8^&brwG  
public SiteFileFetch(SiteInfoBean bean) throws IOException {fPy=,>Nb  
{ C)[,4wt,  
siteInfoBean = bean; @E&J_un  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NW~N}5T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); so,t  
if(tmpFile.exists ()) NO*u9YH?  
{ @6Y?\Wx$w  
bFirst = false; v [wb~uw\  
read_nPos(); :}He\V  
} 9P1OP Xv*p  
else (!ux+K  
{ nHM
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nStartPos = new long[bean.getNSplitter()]; :(/~:^!  
nEndPos = new long[bean.getNSplitter()]; LdYB7T,  
} h9t$Uz^N  
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} {3|t;ZHk  
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public void run() HZ aV7dOZ8  
{ 1T"`vtR  
//获得文件长度 F|'>NL-=  
//分割文件 &p'Y^zL-  
//实例FileSplitterFetch hr#M-K  
//启动FileSplitterFetch线程 {BP{C=p  
//等待子线程返回 "M<8UE\n  
try{ d`QN^)F0#  
if(bFirst) iFd+2S%  
{ 6hno)kd{=  
nFileLength = getFileSize(); H`*LBqDk  
if(nFileLength == -1) EEEh~6?-e  
{ =2`[&  
System.err.println("File Length is not known!"); vNyf64)  
} D>`xzt'.6  
else if(nFileLength == -2) iowTLq!?  
{ Gj1&tjK  
System.err.println("File is not access!"); 0\X\izQ5  
} d6Ht2  
else "|x^|n8i  
{ %v=*Wb\3|  
for(int i=0;i<nStartPos.length;i++) =ElO?9&  
{ Y4J3-wK5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); j_qbAP  
} 4V{:uuI;f  
for(int i=0;i<nEndPos.length-1;i++) ~uj#4>3T  
{ $
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nEndPos = nStartPos[i+1]; ]Z>}6!  
} ;@mS^ik")$  
nEndPos[nEndPos.length-1] = nFileLength; /MIe(,>Uh  
} QJZK|*  
} |tKsgj  
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R4[N:~Z$|  
//启动子线程 oI?3<M^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S(k3 `;K  
for(int i=0;i<nStartPos.length;i++) ^%d\qd`   
{ YX!{P=Ua  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n7zm>&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R"-mKT}  
nStartPos,nEndPos,i); %41m~Wh2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mer/G2#&  
fileSplitterFetch.start(); $[Sc0dzJ  
} +cJL7=V&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8+~ >E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wy<\Tg^J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b(,M1.[qt  
nEndPos = " + nFileLength); 
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// fileSplitterFetch[nPos.length-1].start(); ?j'7l=94A  
;!>rnxB?4  
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//等待子线程结束 I&fozO   
//int count = 0; U&g@.,Y#  
//是否结束while循环 $POu\TO  
boolean breakWhile = false; Q0)#8Rc
m  
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while(!bStop) yks__ylrl(  
{ q}b dx
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write_nPos(); Yz'K]M_Dq  
Utility.sleep(500); y8d]9sX{  
breakWhile = true; [meO[otb  
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for(int i=0;i<nStartPos.length;i++) ;(b9#b.  
{ U#0Q)  
if(!fileSplitterFetch.bDownOver) 46}g7skD  
{ .ODU
 
breakWhile = false; y;4OY  
break; OsTc5K.U~  
} (j%~u&+-  
} MS nG3]{z  
if(breakWhile) %2}-2}[>  
break; ADz ^\  
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//count++; VRVO-Sk  
//if(count>4) M f}~{+  
// siteStop(); c_
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} ~G)S   
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;d@#XIS&-(  
System.err.println("文件下载结束！"); 'S20\hwt-  
} <kfnpB=  
catch(Exception e){e.printStackTrace ();} C+*d8_L  
} B~?*?Z'  
kS%Ydy#:'  
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//获得文件长度 k6;?)~.  
public long getFileSize() aH yx_B  
{ Hf%@3X  
int nFileLength = -1; k)i3   
try{ W6^5YH%  
URL url = new URL(siteInfoBean.getSSiteURL()); jqz ux[6{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pD8+ 4;A  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~jWn4 \  
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int responseCode=httpConnection.getResponseCode(); t DO=P c  
if(responseCode>=400) <h!_>:2L  
{ =R^%(Py  
processErrorCode(responseCode); O24m;oHM  
return -2; //-2 represent access is error 99]R$eT8  
} 'HO$C,1]  
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String sHeader; #?RU;1)Cw  
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for(int i=1;;i++) xn?a. 3b'  
{ m1j*mtu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QpF;:YX^3  
//Utility.log(in.readLine()); vXev$x=w-  
sHeader=httpConnection.getHeaderFieldKey(i); 2d
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if(sHeader!=null) H(H<z,$}T  
{ Oylf<&knF\  
if(sHeader.equals("Content-Length")) M#ZcY  
{ #9=Vg  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '%>=ZhO  
break; W4t;{b  
} 2_)\a(.Qu  
} {WJm  
else G5{T5#  
break; xv46r=>  
} O8f?; ]  
} m\;R2"H%  
catch(IOException e){e.printStackTrace ();} M+-*QyCFK  
catch(Exception e){e.printStackTrace ();} &C:IX\  
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Utility.log(nFileLength); ?K1/ <PE+  
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return nFileLength; mR!1DQ.\<  
} M|VyV(f  
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//保存下载信息（文件指针位置） 1}"++Z73P  
private void write_nPos() a a<8,;  
{ 0`Kj25  
try{ )z>|4@,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qo>b*Ku;  
output.writeInt(nStartPos.length); @<,X0S  
for(int i=0;i<nStartPos.length;i++) x-XD.qh7Hr  
{ Z~GL5]S  
// output.writeLong(nPos); -7SAK1c$  
output.writeLong(fileSplitterFetch.nStartPos); 1eA
7>$w}[  
output.writeLong(fileSplitterFetch.nEndPos); QemyCCP+  
} j*d yp  
output.close(); :{{F *FM;  
} 97Lte5c6r  
catch(IOException e){e.printStackTrace ();} Cwr~HY  
catch(Exception e){e.printStackTrace ();} ^0Zf,40  
} N1}c9}  
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//读取保存的下载信息（文件指针位置） |U~<3.:m:  
private void read_nPos() lVd^ ^T*fh  
{ 84$nT>c  
try{ ?xA:@:l/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XFg9P}"  
int nCount = input.readInt(); 'Jiw@t<o3`  
nStartPos = new long[nCount]; v0ujdp,B  
nEndPos = new long[nCount];  vx\r!]  
for(int i=0;i<nStartPos.length;i++) # q~e^A b  
{ xg30xC[  
nStartPos = input.readLong(); Gw=B:kGk  
nEndPos = input.readLong(); ?yZ+D z\  
} j 7fL7:,T  
input.close(); $yN{-T"  
} K'55O&2  
catch(IOException e){e.printStackTrace ();} #:jHp44J  
catch(Exception e){e.printStackTrace ();} V4hiGO[  
}  Fiv3 {.  

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private void processErrorCode(int nErrorCode) ``V" D  
{ WJ$bf(X*  
System.err.println("Error Code : " + nErrorCode); i1UiNJh86  
} Ha(c'\T(\  
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j >Ht@Wi  
//停止文件下载 Hfv7LM  
public void siteStop() yUeCc"Vf  
{ ()2I#  
bStop = true; 4hO!\5-w:  
for(int i=0;i<nStartPos.length;i++) V08?-Iz$  
fileSplitterFetch.splitterStop(); ]99|KQ<s  
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} H  >j  
} +j#+8Ze  
//负责部分文件的抓取 u&^b~#T  
**FileSplitterFetch.java UG'Q]S#!  
*/ i% w3/m  
package NetFox; 8k2?
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import java.io.*; # Nk;4
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import java.net.*; *7:>EP  
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public class FileSplitterFetch extends Thread { PZ2;v<  
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String sURL; //File URL [\'%?BH(^  
long nStartPos; //File Snippet Start Position B%
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long nEndPos; //File Snippet End Position eds o2  
int nThreadID; //Thread's ID cq5jPZ}  
boolean bDownOver = false; //Downing is over 3Ko/{f  
boolean bStop = false; //Stop identical -mAUo;O  
FileAccessI fileAccessI = null; //File Access interface NYyh|X:m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %;cddLQ\xY  
{ ,
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this.sURL = sURL; Y}x>t* I  
this.nStartPos = nStart; ;l4[%xld  
this.nEndPos = nEnd; 
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nThreadID = id; hwu]Er.g
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 4 kn|^  
} %9w::hav  
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public void run() rEv@YD   
{ x%}^hiO<q  
while(nStartPos < nEndPos && !bStop) ,">]`|?  
{ 7_%"BVb"  
{`J)j6;  

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try{ `lQ3C{}  
URL url = new URL(sURL); $Oq^jUJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5)FJ:1-  
httpConnection.setRequestProperty("User-Agent","NetFox"); i;]"n;>+/  
String sProperty = "bytes="+nStartPos+"-"; {,3>"  
httpConnection.setRequestProperty("RANGE",sProperty); T3~k>"W  
Utility.log(sProperty); 11TL~xFh  
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InputStream input = httpConnection.getInputStream(); ~KHVY)@P  
//logResponseHead(httpConnection); *$yR*}A  
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byte[] b = new byte[1024]; %Qc La//  
int nRead; Hcl(3>Jn2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K$>%e36Cc  
{ ->sm+H-*  
nStartPos += fileAccessI.write(b,0,nRead); {F3xJ[  
//if(nThreadID == 1) prYs $j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oT^{b\XN  
} LISMngQ.  
./,/
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Utility.log("Thread " + nThreadID + " is over!"); qo p^;~  
bDownOver = true; B$-R-S6  
//nPos = fileAccessI.write (b,0,nRead); &7<TAo;O  
} 5Eg1Q YVt  
catch(Exception e){e.printStackTrace ();} 1|RANy  
} =5Q]m6-SgV  
} 2-7IJ\  
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//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) }M1`di4e  
{ '3_]Gu-D  
for(int i=1;;i++) Ge2q%  
{ s1=X>'q  
String header=con.getHeaderFieldKey(i); :QpuO1Gu  
if(header!=null) ^?U!pq-`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q ]M+/sl  
Utility.log(header+" : "+con.getHeaderField(header)); i'4B3  
else w,w{/T+B  
break; j:5=s%S  
} }3o|EXx=  
} W"zab
 
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public void splitterStop()  UmNa[s  
{ )T';qm0w  
bStop = true; RMK"o?  
} eb.O#Y  
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} !+1<E*NQ S  
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/* #z&&M"*a|  
**FileAccess.java 4xk|F'
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*//文件访问(定位，写) uv=.2U46  
package NetFox; }
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import java.io.*; .Si,dc\  
*FC=X)_&W  
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public class FileAccessI implements Serializable{ k40* e\  
bvS(@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 afv~r>q(-  
RandomAccessFile oSavedFile; OZx W?wnd  
long nPos; )>.&N[
v  
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public FileAccessI() throws IOException {XNREjhm  
{ hJn%mdx~w|  
this("",0); crqpV F]1]  
} V=zi >o`   
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public FileAccessI(String sName,long nPos) throws IOException &{>cZh}\  
{ ~p1j`r;  
oSavedFile = new RandomAccessFile(sName,"rw"); ]%|GmtqZs,  
this.nPos = nPos; #bMuvaP~  
oSavedFile.seek(nPos); WOQP$D9  
} Pf|siC^;s~  
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public synchronized int write(byte[] b,int nStart,int nLen) >H'4{|  
{ {7$c8i  
int n = -1; WKT4D}{1  
try{ `wus\&
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oSavedFile.write(b,nStart,nLen); 3D`YZ#M  
n = nLen; l%?T2Fm3>  
} @\0Eu212  
catch(IOException e) 99}(~B  
{ ?0)&U  
e.printStackTrace (); F">
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} ? i( %  
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return n; q8^^H$<Db  
} %F!1  
#>%X_o-o23  
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} BDq%'~/^  
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/* aemc2b*  
**SiteInfoBean.java :Qumb  
*/ >iD )eB  
package NetFox; pV20oSJNt  
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public class SiteInfoBean { %1O;fQL  
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private String sSiteURL; //Site's URL ;cPy1  
private String sFilePath; //Saved File's Path T2SP W@#Z3  
private String sFileName; //Saved File's Name Z2TL#@  
private int nSplitter; //Count of Splited Downloading File BB~OqZIP  
D&}3$ 7>  
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public SiteInfoBean() {) Q@c)'  
{//nSplitter的缺省值为5 R,F[XI+=N  
//default value of nSplitter is 5 q>mE< (-M  
this("","","",5); W6"v)Jc>_  
} 3 |hHR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IG|X!l  
{ o3I Tr';  
sSiteURL= sURL; fRtUvC-#H  
sFilePath = sPath; O)ME"@r@:  
sFileName = sName; 'h^0HE\~p  
this.nSplitter = nSpiltter; `FYv3w2  
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} tZ^Ou89:rG  
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public String getSSiteURL() 4g :>[q  
{ 5e$~)
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return sSiteURL; $: ]o]a  
} e XfZ5(na  
4$*%gL;f^  
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public void setSSiteURL(String value) g>dA$h%  
{ *M$0J'-B
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sSiteURL = value; gF$V$cU  
} A
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public String getSFilePath() <^z
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{ ~$p2#AqX  
return sFilePath; o(S{VGi,  
} B x (uRj  
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public void setSFilePath(String value) \T<$9aNb  
{ 2I&o69x?  
sFilePath = value; Kj<^zo%w  
}  ^}:#  
3'^k$;^  
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public String getSFileName() tQH+)*  
{ %*&UJpbA  
return sFileName; o>7ts&rk  
} iK12pw  
S(uf(q|{  
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public void setSFileName(String value) wg0 \_@3  
{ ,4ei2`wV  
sFileName = value; s
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} L2, 1Kt7  
z.Y$7bf)  
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public int getNSplitter() QF&W`c  
{ !zPa_`P  
return nSplitter; Db6om7N  
} |\U5),m  
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public void setNSplitter(int nCount) h=(DX5:A  
{ F0:A]`|  
nSplitter = nCount; ^_
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} 4H|(c[K;  
} xj[(P$,P  
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ap{
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/* O9g{+e`  
**Utility.java :%sXO  
*/ FI
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package NetFox; t 0-(U\  
F$^
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public class Utility { L5qwWvbT  
-.T&(&>^  
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public Utility() j%y$_9a7  
{ h+aS
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}J7zTj~{  
<
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} Tp0b
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//线程睡眠 VMCLHpSfW  
public static void sleep(int nSecond) dlG=Vq&Y  
{ KID,|K  
try{ S6fL>'uQ  
Thread.sleep(nSecond); ak:ibV  
} Qu7T[<  
catch(Exception e) >P/][MT  
{ xY$iz)^0&  
e.printStackTrace (); @"o@}9=d  
} kWNV%RlSx  
} &[At`Nw71  
1?| flK  
//日志 SL,p36N  
public static void log(String sMsg) 2e|N@j &  
{ ^qC;Nh4F  
System.err.println(sMsg); Ton94:9bZ  
} 3;8!rNN  
ZvUC
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Y& F=t/U2  
public static void log(int sMsg) HU9Sl*/  
{ 4[BG#  
System.err.println(sMsg); gl]E_%tH  
} cetvQAGXY  
} #^4,GLIM  
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P)uDLFp]  
/* 8o/}}=m$  
**TestMethod.java 5r?m&28X  
*/ NuYkz"O]  
package NetFox; 1Jj Y!  
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public class TestMethod { fPR$kch  
tw(JZDc  
[2dn\z28  
public TestMethod() (E,Yo  
{ ///xx/weblogic60b2_win.exe Raw)9tUt  
try{ z.6$W^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Gdg)9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H
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SiteFileFetch fileFetch = new SiteFileFetch(bean); b]7GmRekl  
fileFetch.start(); /RyR>G!  
} ?h0X,fl3  
catch(Exception e){e.printStackTrace ();} !=y]Sv~h  
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} Dk='+\  
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public static void main(String[] args) o=RM-tR`v  
{ T2D<UhP  
new TestMethod(); w ~dk#=  
} 2>\v*adG  
} }/,HM9Ke  
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