http断点续传简单实现（java)

/* f4]N0  
**SiteFileFetch.java 9R9__w;  
*/ D(y+1^>  
package NetFox; )y9;OA  
import java.io.*; Y/.AUN Z  
import java.net.*; NH7`5mF$  
A/q2g7My  
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public class SiteFileFetch extends Thread { $4Z+F#mx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s|Z:}W?{  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 )PR3s1S^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9n1ZVP.a
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long nFileLength; //文件长度 "(s6aqO$  
boolean bFirst = true; //是否第一次取文件 K&=D-50%  
boolean bStop = false; //停止标志 kOw=c Gt  
File tmpFile; //文件下载的临时信息 ^_v[QV  
DataOutputStream output; //输出到文件的输出流 AY#wVy  
t)YUPDQ@J  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <fN; xIB  
public SiteFileFetch(SiteInfoBean bean) throws IOException *)u?~r(F  
{ 5L8&/EN9-  
siteInfoBean = bean; ^:`oP"%-T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~12_D'8D[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "`pNH'  
if(tmpFile.exists ()) S]}}A  
{ tAF]2VV(e  
bFirst = false; \tY"BC4.  
read_nPos(); i+g~ Uj}h  
} ,V,f2W 4  
else
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{ 93j{.0]X  
nStartPos = new long[bean.getNSplitter()]; M\Se_  
nEndPos = new long[bean.getNSplitter()]; I%oRvg|q  
} eP"`,<  
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} j~bAbOX12  
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public void run() r'/\HWNP  
{ Hkdf$$
\  
//获得文件长度 B`
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//分割文件 2nv[1@M  
//实例FileSplitterFetch 5F2_xH$5  
//启动FileSplitterFetch线程 *ZaaO^!  
//等待子线程返回 GcT;e5D  
try{ SxJ$
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if(bFirst) l3.  
{ iv*V#J>  
nFileLength = getFileSize(); .}q]`<]ze  
if(nFileLength == -1) ;f:gX`"\  
{ ^i+[m  
System.err.println("File Length is not known!"); }Z\wH*s`  
} K UKACUL  
else if(nFileLength == -2) En(7(qP6}  
{ B{C_hy-fw  
System.err.println("File is not access!"); ^T:gb]i'Qa  
} ?]c+j1i  
else 8V9[a*9  
{ \q "N/$5{f  
for(int i=0;i<nStartPos.length;i++) ef=K_, _  
{ <:&de8bT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >{C\H.N  
} t6+YXjXK  
for(int i=0;i<nEndPos.length-1;i++) B:< ]Hl$  
{ y`yZR _  
nEndPos = nStartPos[i+1]; kbYeV_OwM  
} Bq@zaMv  
nEndPos[nEndPos.length-1] = nFileLength; i
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} LvcuZZ`1a  
} P ZxFZvE  
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//启动子线程 Tkw;pb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; LH2PTW\b!6  
for(int i=0;i<nStartPos.length;i++) }u%"$[I}  
{ sYqgXE.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y500Xs[c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i0:>Nk  
nStartPos,nEndPos,i); :]PM_V|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KVkMU?6  
fileSplitterFetch.start(); $d/&k`  
} (&[[46  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +H_MV=A^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )55\4<ty  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2#vv$YD  
nEndPos = " + nFileLength); =wG+Ao  
// fileSplitterFetch[nPos.length-1].start(); <P_ea/5:|  
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//等待子线程结束 /*$hx@ih  
//int count = 0; fuUm}N7  
//是否结束while循环 @*>Sw>oet  
boolean breakWhile = false; C$d>_r  
t{dSX?<nt  
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while(!bStop) }fZ`IOf  
{ h5"Ov,K3[  
write_nPos(); ibpzeuUl  
Utility.sleep(500); Pf<[|yu4?  
breakWhile = true; oH#v6{y  
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for(int i=0;i<nStartPos.length;i++) }7s>B24J  
{ HfB@vw^  
if(!fileSplitterFetch.bDownOver) HN6}R|IH  
{ El- ? %  
breakWhile = false; e5?PkFV^a1  
break; a.@qGsIH  
} ~Rpm-^  
} ~+G#n"Pn  
if(breakWhile) WC,+Cn e  
break; ?wb+L  
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//count++; pI.+"Hz  
//if(count>4) =IU*}>#  
// siteStop(); \.uc06  
} e`K)_>^n#  
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System.err.println("文件下载结束！"); 1LnyWZ  
} dRi5hC$  
catch(Exception e){e.printStackTrace ();} B@y(.  
} <7_KeOLJ  
::5E8919  
!#2=\LUC  
//获得文件长度 ?GA&f2]a  
public long getFileSize() L<V3KS2y  
{ +7V{ABfGl  
int nFileLength = -1; zYY$
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try{ *sw7niw  
URL url = new URL(siteInfoBean.getSSiteURL()); O#a6+W
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (X[CsaXt  
httpConnection.setRequestProperty("User-Agent","NetFox"); N K]B?  
V9wI\0  
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int responseCode=httpConnection.getResponseCode(); \x{;U#B[3>  
if(responseCode>=400) l_rn++  
{ Z8#Gwyinx  
processErrorCode(responseCode); S8d8%R~1=h  
return -2; //-2 represent access is error 5kypMHJm  
} nmU_N:Y  
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String sHeader; A3N]8?D  
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for(int i=1;;i++) H( jXI  
{ 4mjgt<`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y-mK+12  
//Utility.log(in.readLine()); LhXUm  
sHeader=httpConnection.getHeaderFieldKey(i); WLa!.v>  
if(sHeader!=null) H9)m^*  
{ "syh=BC v  
if(sHeader.equals("Content-Length"))  p?D2)(  
{ <*!i$(gn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U9y|>P\)T  
break; JA)?p{j  
} tR0pH8?e"  
} V r(J+1@  
else ?~"bR%  
break; GNf482  
} fWc|gq  
} ;22l"-F  
catch(IOException e){e.printStackTrace ();} CT9   
catch(Exception e){e.printStackTrace ();} s=6}%%q6  
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Utility.log(nFileLength); T<3BT  
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return nFileLength; FWue;pw3  
} \!vN  
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//保存下载信息（文件指针位置） n79QJl/  
private void write_nPos() Hs?e0Z=N  
{ w=]Ks'C]  
try{ Pg9hW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pLa[}=  
output.writeInt(nStartPos.length); 7cAXd#sI  
for(int i=0;i<nStartPos.length;i++) fDE%R={!n5  
{ ]5~s"fnG  
// output.writeLong(nPos); e^4 p%  
output.writeLong(fileSplitterFetch.nStartPos); =S'%`]f?  
output.writeLong(fileSplitterFetch.nEndPos);
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} iovfo2!hD  
output.close(); Uz cx6sw  
} 2%*MW"Q  
catch(IOException e){e.printStackTrace ();} ] Z8Vj7~  
catch(Exception e){e.printStackTrace ();} E$9Y
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} t?o,RN:  
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//读取保存的下载信息（文件指针位置） -9RDr\&`(  
private void read_nPos() g%F"l2M  
{ g(VNy@  
try{ RLlU" sw+{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1im^17X  
int nCount = input.readInt(); Go,N>HN  
nStartPos = new long[nCount]; y;mj^/SxK  
nEndPos = new long[nCount]; 5@*'2rO&!  
for(int i=0;i<nStartPos.length;i++) ]E  =Iu  
{ K{n{KB&_&  
nStartPos = input.readLong(); %r&-gWTQ,  
nEndPos = input.readLong(); p!]6ll^  
} gtUUsQ%y.  
input.close(); J=.`wZQkS  
} nJPyM/p  
catch(IOException e){e.printStackTrace ();} b:qY gg  
catch(Exception e){e.printStackTrace ();} dKl^jsd  
} S'oGt&Z<  
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private void processErrorCode(int nErrorCode) QwhRNnE=  
{ 0]D0{6x8  
System.err.println("Error Code : " + nErrorCode); VMoSLFp^R  
} BpX6aAx  
#:T-hRu  
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//停止文件下载 VqL.iZ-  
public void siteStop() 6}FO[  
{ .>z][2oz  
bStop = true; ng:Q1Q
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for(int i=0;i<nStartPos.length;i++) lL]y~u  
fileSplitterFetch.splitterStop(); + [Hh,I7  
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} iH^z:%dP  
} =^ T\Xs;GK  
//负责部分文件的抓取 rJ KZ)N{  
**FileSplitterFetch.java (E]!Z vE  
*/ p4p@^@<>X  
package NetFox; 0Z{j>=$  
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import java.io.*; 8w({\=
 
import java.net.*; }w4QP+ x  
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public class FileSplitterFetch extends Thread {  |W<+U  
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String sURL; //File URL `K,1K  
long nStartPos; //File Snippet Start Position YJ(*wByM  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID 'l,V*5L  
boolean bDownOver = false; //Downing is over u{["50~  
boolean bStop = false; //Stop identical Q]p(u\*  
FileAccessI fileAccessI = null; //File Access interface y\{%\$  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v9T_
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{ Z4IgBn(Z_}  
this.sURL = sURL; HYmn:?H  
this.nStartPos = nStart; :kfp_o+J  
this.nEndPos = nEnd; pKi&[  
nThreadID = id; (rg;IXAq%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i1RiGS
 
} vX]Gf4,  
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public void run() %u;~kP|S%  
{ _ 84ut  
while(nStartPos < nEndPos && !bStop) U4G`ZKv(!  
{ ,-z9 #t  
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try{ ;NRF=d>  
URL url = new URL(sURL); c&L"N!4z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ao/ jt<  
httpConnection.setRequestProperty("User-Agent","NetFox"); *}8t{ F@k  
String sProperty = "bytes="+nStartPos+"-"; T9s2bC.z55  
httpConnection.setRequestProperty("RANGE",sProperty); c_elShK8#  
Utility.log(sProperty); 8zMu7,E  
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InputStream input = httpConnection.getInputStream(); *YlV-C<}W"  
//logResponseHead(httpConnection); V%Sy"IG  
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byte[] b = new byte[1024]; dXnl'pFS  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v%ioj
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{ ~/*MY  
nStartPos += fileAccessI.write(b,0,nRead); a+Ac[>  
//if(nThreadID == 1) Y/7 $1
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4Fm90O  
} ZI=v.wa  
*E{2J:`  
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Utility.log("Thread " + nThreadID + " is over!"); 5<w g8y  
bDownOver = true; ?Ae ven  
//nPos = fileAccessI.write (b,0,nRead); HbW0wuI  
} >KJ+-QuO&  
catch(Exception e){e.printStackTrace ();} \<g*8?yFs  
} M|Rb&6O  
} .?l\g-;=  
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//打印回应的头信息 4t)/  
public void logResponseHead(HttpURLConnection con) f!JS= N?3  
{ KVJ_E
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for(int i=1;;i++) QqU!Najf  
{ AA7C$;Z15~  
String header=con.getHeaderFieldKey(i); S9
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if(header!=null) )6aAB|  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  s~Te  
Utility.log(header+" : "+con.getHeaderField(header)); zE_i*c"`  
else 4#lo$#  
break; mWvl38  
} Q@HopiC  
} JeE;V![  
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public void splitterStop() 9th,VnD0  
{ qo|WXwP2  
bStop = true; .p(T^ m2A*  
} 9B9(8PVG  
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} j?+X\PtQ  
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/* q*>&^V$M  
**FileAccess.java RVQh2'w  
*//文件访问(定位，写) J_4!
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package NetFox; FIsyiSY<j  
import java.io.*; kbe-1 <72  
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public class FileAccessI implements Serializable{ ^RI?ybDd  
:n-]>Q>5=k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s']Bx=  
RandomAccessFile oSavedFile; $A-J,_:T<  
long nPos; 
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public FileAccessI() throws IOException uwy:t!(j  
{ <Pi|J-Y  
this("",0); Ug<#
en  
} LBZ+GB  
!/]WrGqbS  
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public FileAccessI(String sName,long nPos) throws IOException =UfsL%  
{ XSyHk"g`  
oSavedFile = new RandomAccessFile(sName,"rw"); m+T;O/lG0{  
this.nPos = nPos; e0,|Wm  
oSavedFile.seek(nPos); q}?4f*WC  
} ys
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public synchronized int write(byte[] b,int nStart,int nLen) WL"^>[Vq  
{ TtTj28k7  
int n = -1; j=r P:#  
try{ @pRlxkvV  
oSavedFile.write(b,nStart,nLen); tu66'z  
n = nLen; *(T:,PY  
} /$p6'1P8  
catch(IOException e) [UWdW  
{ #;2n;.a  
e.printStackTrace (); )O@]uY  
} |}di&y@-JI  
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return n; LAS'u"c|  
} 2so!  
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} J`].:IOh  
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/* cmU1!2.1E  
**SiteInfoBean.java 1oWED*B  
*/ heC/\@B  
package NetFox; $m-2HhqZ  
(Hb:?(  
9 %I?).5  
public class SiteInfoBean { r w2arx  
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private String sSiteURL; //Site's URL VoWNW  
private String sFilePath; //Saved File's Path jk[1{I/  
private String sFileName; //Saved File's Name _n50C"X=&(  
private int nSplitter; //Count of Splited Downloading File l:,'j@%  
?!d&E?9\  
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public SiteInfoBean() '
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{//nSplitter的缺省值为5 !C3MFm{B  
//default value of nSplitter is 5 B][U4WJ)  
this("","","",5); #(N+(():  
} D"2&P^-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YSic-6z0Ms  
{ lJ}_G>GJ  
sSiteURL= sURL; q=Sgk>NA  
sFilePath = sPath; %Q fO8P  
sFileName = sName; e]$}-i@#  
this.nSplitter = nSpiltter; 1Vrh4g.l  
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} qzKdQ&vO  
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public String getSSiteURL() U4C 9<h&  
{ 2a`o &S  
return sSiteURL; L\xk:j1[  
} Ez fN&8E  
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public void setSSiteURL(String value) t!W(_8j  
{ CUBEW~X}M  
sSiteURL = value;
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} KWowN;  
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public String getSFilePath() `(ue63AZ  
{ ~obqG!2m  
return sFilePath; "$+Jnc!!  
} lm-dW'7&  
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public void setSFilePath(String value) 'MUv5Th  
{ 4ew" %Cs*  
sFilePath = value; N~goI#4  
} (_mnB W  
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public String getSFileName() cdl&9-}  
{ Zw5Ni Xj  
return sFileName; bpJ(XN}E  
} ;g5m0l5  
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public void setSFileName(String value) Z'`gJ&6n  
{ Xqg@ e:g  
sFileName = value; Ce9|=Jx!  
} "GMBjT8  
P;=n9hgHI  
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public int getNSplitter() SPX$U5&  
{ |:q=T ~x  
return nSplitter; 7~^GA.92  
} I7|Pi[e  
)t0$qd ]  
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public void setNSplitter(int nCount) rzhWw-GY  
{ J%v=yBC2  
nSplitter = nCount; +%T\`6  
}  Ch&a/S}  
} U\4g#!qj  
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[842&5Pd?  
/* VRWAm>u  
**Utility.java fHE<(  
*/ a oD`=I*<  
package NetFox; z1PBM
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public class Utility { !"HO]3-o  
(6?9BlH~  
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public Utility() .zA^)qgL  
{ twL3\ }N/B  
<keVrCR  
2h|MXI\g  
} b
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@| M|+k3  
//线程睡眠 @Lpq~ 1eZB  
public static void sleep(int nSecond) \\PjKAsh  
{  $UMFNjL  
try{ [w>$QR  
Thread.sleep(nSecond); s:>VaGC  
} ~("5yG  
catch(Exception e) 1->dMm}G[  
{ jqWu  
e.printStackTrace (); \f]k 
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} <C1H36p  
} C]O(T2l{l  
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//日志 oX#Q<2z*  
public static void log(String sMsg) `slL%j
^"  
{ Yl4^AR&  
System.err.println(sMsg); M>wYD\oeg  
} D"Bl:W'?j  
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public static void log(int sMsg) s>B5l2Q4  
{ j`JMeCG=Ee  
System.err.println(sMsg); )
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} iZ#!O*>  
} ]{)a,c NG  
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9=vMgW  
/* WKts[Z  
**TestMethod.java A_XY'z1  
*/ mC4zactv  
package NetFox; e}D3d=6`  
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K,Ef9c/+K  
public class TestMethod { :8L8q<U  
<6EeD5{*  
:By?O"LQ  
public TestMethod() L6t+zIUc-~  
{ ///xx/weblogic60b2_win.exe Vi>,kF.fV  
try{ y~Bh  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8;d:-C
p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W3]_m8,Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8qk?E6  
fileFetch.start(); .GsV>H  
} 6bomh2  
catch(Exception e){e.printStackTrace ();} X@$f$=  
j2Cks_$:  
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} > A Khf  
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public static void main(String[] args) .R)D3NZp  
{ j|4<i9^}  
new TestMethod(); m4TE5q%3
 
} R}G4rO-J  
} ebm])~ZL  
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