http断点续传简单实现（java)

/* Zw(*q?9\  
**SiteFileFetch.java e6s-;
 
*/ 
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package NetFox; $-""=O|"  
import java.io.*; .S/W_R  
import java.net.*; dP0!?J Y  
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public class SiteFileFetch extends Thread { >W2Z]V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9TGjcZ1S'  
long[] nStartPos; //开始位置 Qxj &IX  
long[] nEndPos; //结束位置 ,sPsL9]$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rtcY(5Q  
long nFileLength; //文件长度 *au&ODa  
boolean bFirst = true; //是否第一次取文件 =8OPjcX.V  
boolean bStop = false; //停止标志 7NG^X"N{Ul  
File tmpFile; //文件下载的临时信息 )mO|
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DataOutputStream output; //输出到文件的输出流 b{H&%Jx)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =!3G,qV  
public SiteFileFetch(SiteInfoBean bean) throws IOException GCul6,w  
{ Q7]:vs)%  
siteInfoBean = bean; $?p^ m`t_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N>;"r]Rl"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $x;wnXXXM  
if(tmpFile.exists ()) btb-MSkO  
{ C`OdMM>D  
bFirst = false; TL@_m^SM  
read_nPos(); GIQ/gM?Pv  
} j
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else d|Wpub  
{ cw#p!mOi~  
nStartPos = new long[bean.getNSplitter()]; Mj5=
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nEndPos = new long[bean.getNSplitter()]; N(mhg
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} 2#'{
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} vvw6 GB,M  
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public void run() 1vQf=t%lw  
{ !$hrK6o  
//获得文件长度 y|V/xm+Fp  
//分割文件 ]od]S8$5  
//实例FileSplitterFetch S:{hgi,T*  
//启动FileSplitterFetch线程 ch,<4E/c[R  
//等待子线程返回 +g ovnx  
try{ 7~TE=t  
if(bFirst)  ~d_Z?Z  
{ n5"rSgUtE  
nFileLength = getFileSize(); JE,R[` &  
if(nFileLength == -1) =3lUr<Ze  
{ 7}(LO^,A  
System.err.println("File Length is not known!"); 6grJoim|  
} x, a[ p\1  
else if(nFileLength == -2) x-) D@dw<  
{ 0iqa]Am  
System.err.println("File is not access!"); yd5r]6ej  
} ftF?T.dx  
else /ow/)\/}  
{ .z7
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for(int i=0;i<nStartPos.length;i++) !cT#G  
{ N8}R<3/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K,%H*1YKK  
} j#y_#  
for(int i=0;i<nEndPos.length-1;i++) $bh2zKB)  
{ gE(QVbh(  
nEndPos = nStartPos[i+1]; O:Bfbna  
} [ivz/r(Rj  
nEndPos[nEndPos.length-1] = nFileLength; ja70w:ja  
} g"
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} 3G8BYP  
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//启动子线程 l/[@1(F  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =|S8.|r+  
for(int i=0;i<nStartPos.length;i++) xZPSoxu  
{ _ZIaEJjH/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), akgXI^K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (qlIQC  
nStartPos,nEndPos,i); ~-lIOQ.v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zC!]bWsD  
fileSplitterFetch.start(); Pk[f_%0  
} $1.iMHb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lF5;Kc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &1893#V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W"AWhi{h  
nEndPos = " + nFileLength); n99:2r_  
// fileSplitterFetch[nPos.length-1].start(); 's@v'u3  
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//等待子线程结束 9fMg?  
//int count = 0; jpZX5_o  
//是否结束while循环 9z\q_0&i  
boolean breakWhile = false; !Qjpj KRy  
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while(!bStop) M:6H%6eT  
{ "w=p@/C  
write_nPos(); DUEA"m h  
Utility.sleep(500); U# Y?'3:  
breakWhile = true; ?*K;+@EH  
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{}N*e"<O  
for(int i=0;i<nStartPos.length;i++) wJ1qJ!s@  
{ lg&"=VXx51  
if(!fileSplitterFetch.bDownOver) %;^[WT`,  
{ Thn-8DT  
breakWhile = false; LPb43  
break; k7>*fQ89@  
} f|WNPFQ$x  
} m/=,O_  
if(breakWhile) x
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break; hz<kR@k}  
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i' %V}2  
//count++; RZjTUMAz4  
//if(count>4) :m_0WT  
// siteStop(); %<O'\&!,  
} {3yzC  
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System.err.println("文件下载结束！"); ^USj9HTK  
} Ko\m8\3?fK  
catch(Exception e){e.printStackTrace ();} {Mp>+e@xx  
} Ag }hyIl  
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//获得文件长度 LDBxw  
public long getFileSize() xVuGeanCv  
{ o ]2=5;)  
int nFileLength = -1; ppR~e*rv-  
try{ S-gL]r3G8  
URL url = new URL(siteInfoBean.getSSiteURL()); fxI>FhU_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  h#^I
T  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dgj`_yd  
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)6PZ.s/F6p  
int responseCode=httpConnection.getResponseCode(); zc'!a"  
if(responseCode>=400) 4FQU$f  
{ NAZxM9  
processErrorCode(responseCode); _T6WA&;8  
return -2; //-2 represent access is error 7Nh6 `  
} [ k^6#TQcn  
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String sHeader; A{: a kK  
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for(int i=1;;i++) ;s3"j~5m)  
{ <#7}'@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~YlbS-  
//Utility.log(in.readLine()); UB|Nx(V s  
sHeader=httpConnection.getHeaderFieldKey(i); y,DK@X  
if(sHeader!=null) @+syD  
{ j()_ VoB1  
if(sHeader.equals("Content-Length")) M< *5Y43  
{ >9esZ
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1zGEf&rv:  
break; (toGU  
} |C=^:@}ri?  
} C&NoEtL>s  
else 59$mfW o>  
break; 7_E+y$i=  
} 6^mO<nB   
} HMgZ&
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catch(IOException e){e.printStackTrace ();} Q6MDhv,  
catch(Exception e){e.printStackTrace ();} _R8)%<E  
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Utility.log(nFileLength); QP7EPaW  
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return nFileLength; H 
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} >pv~$  
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//保存下载信息（文件指针位置） `;hsOfo  
private void write_nPos() oE"!  
{ n1y#gC  
try{ r7C m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yHCQY4/  
output.writeInt(nStartPos.length); Fu )V2[TY  
for(int i=0;i<nStartPos.length;i++) ZA1?'  
{ iq5h[  
// output.writeLong(nPos); +m:U9K(\h  
output.writeLong(fileSplitterFetch.nStartPos); !b rN)b)f  
output.writeLong(fileSplitterFetch.nEndPos); =XQ3sk6U  
} n6O1\}YB  
output.close(); UG Fx  
} 9D(M>'Bh  
catch(IOException e){e.printStackTrace ();} L;,Nh  
catch(Exception e){e.printStackTrace ();} ^-~.L: }q  
} q_OIzZ@  
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//读取保存的下载信息（文件指针位置） qnrf%rS  
private void read_nPos() +z>*m`}F  
{ 5}*aP  
try{ 9C|T/+R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9 ?MOeOV8  
int nCount = input.readInt(); u<!!%C~+=  
nStartPos = new long[nCount]; <C+:hsS=  
nEndPos = new long[nCount]; {8@?9Z9R{  
for(int i=0;i<nStartPos.length;i++) .Z8 x!!Q*  
{ udp&U+L  
nStartPos = input.readLong(); un W{ZfEC  
nEndPos = input.readLong(); p tv  
} 6:-qL}  
input.close(); @r+ErFI  
} P6i4Dr  
catch(IOException e){e.printStackTrace ();} KbMgat
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catch(Exception e){e.printStackTrace ();} X[j4V<4O  
} gBYL.^H^l  
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private void processErrorCode(int nErrorCode) C(?>l.QGw  
{ ;)0vxcMB  
System.err.println("Error Code : " + nErrorCode); kQ.atr`?e  
} EVgn^,  
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//停止文件下载 rU<  H7U  
public void siteStop() r$k *:A$%  
{ o$d;
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bStop = true; y\5V(Q\  
for(int i=0;i<nStartPos.length;i++) S,G=MI"  
fileSplitterFetch.splitterStop(); +_:Ih,-   
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} r5lp<md  
} DXSZ#^,S[W  
//负责部分文件的抓取 ;NLL?6~  
**FileSplitterFetch.java L9fhe,en  
*/ H!Uy4L~>  
package NetFox; r.-NfK4  
=c-j4xna>  
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import java.io.*; 7<IrN\@U  
import java.net.*; e<~uU9 lg1  
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public class FileSplitterFetch extends Thread { Vfg144FG'  
;lW0p8  
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String sURL; //File URL TQE3/IL  
long nStartPos; //File Snippet Start Position \{{B57/Isq  
long nEndPos; //File Snippet End Position o6xl,T%  
int nThreadID; //Thread's ID [g=yuVXNZZ  
boolean bDownOver = false; //Downing is over }4cLU
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boolean bStop = false; //Stop identical U g]6i+rp  
FileAccessI fileAccessI = null; //File Access interface cFGP3Q4{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g@MTKqs  
{ Y_Ej-u+>{  
this.sURL = sURL; J%j#gyTU  
this.nStartPos = nStart; +c}fDrr)  
this.nEndPos = nEnd; {-Yp~HQF  
nThreadID = id; |;OM,U2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #jA|
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} 3<m"z9$  
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public void run() +r4US or  
{ 2x$\vL0  
while(nStartPos < nEndPos && !bStop) Sh2q#7hf  
{ jY87NHg  
lNqXx{!k  

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try{ @iC
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URL url = new URL(sURL); =J0FT2 d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); isWB)$q  
httpConnection.setRequestProperty("User-Agent","NetFox"); >@h0@N  
String sProperty = "bytes="+nStartPos+"-"; | 2p\M?@  
httpConnection.setRequestProperty("RANGE",sProperty); rIW`(IG_  
Utility.log(sProperty); Tk.MtIs)V}  
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InputStream input = httpConnection.getInputStream(); =*"Amd,  
//logResponseHead(httpConnection); 6tzZ j:yq  
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byte[] b = new byte[1024]; jqb,^T|j;m  
int nRead; ou,W|<%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @_N -> l  
{ 0e:KiUr  
nStartPos += fileAccessI.write(b,0,nRead); k(%RX_]C  
//if(nThreadID == 1) N;r,B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lm-}W "7  
} <0v'IHlZ8  
4zJ9bF4  
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Utility.log("Thread " + nThreadID + " is over!"); 2kCJqyWy
 
bDownOver = true; C[gSiL  
//nPos = fileAccessI.write (b,0,nRead); =k3QymA  
} _or$^.='  
catch(Exception e){e.printStackTrace ();} FCqs'  
} {'>X6:  
} GN=F-*2  
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//打印回应的头信息 Y$oBsg\v  
public void logResponseHead(HttpURLConnection con) _IT,>#ba  
{ ELY$ ]^T  
for(int i=1;;i++) [>C^ 0\Z~  
{ &(Xp_3PO  
String header=con.getHeaderFieldKey(i); [}P|OCW  
if(header!=null) 1(On.Y=   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r~t&;yRv  
Utility.log(header+" : "+con.getHeaderField(header)); 4~Lw:o1a  
else p)TH^87  
break; `pII-dSC%  
} 6"ZQN)7  
} Zh3]bg5  
b!7"drge:  
8&dmH&  
public void splitterStop() %pTbJaM\U  
{ ?;^_%XSQ*  
bStop = true; '|WMt g  
} 3 5|5|ma  
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} W]6Y buP:  
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/* %9Ulgs8=  
**FileAccess.java atl0#FBd  
*//文件访问(定位，写) T(ponLh  
package NetFox; p(f)u]1`  
import java.io.*; Vfc9+
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public class FileAccessI implements Serializable{ kw=+"U  
$lV0TCgba8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 siyJjE)}w  
RandomAccessFile oSavedFile; }\l5|Ft[!  
long nPos; `[o^w(l:5@  
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public FileAccessI() throws IOException <(
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{ |q5\1}@:
  
this("",0); EZBk;*=B  
} m"+9[d_u  
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}.`ycLW'  
public FileAccessI(String sName,long nPos) throws IOException c*1B*_08  
{ oSy[/Y44a  
oSavedFile = new RandomAccessFile(sName,"rw"); 6aMqU?-
 
this.nPos = nPos; vK2L"e  
oSavedFile.seek(nPos); 5^P)='0*  
} Oo=}j  
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s "*Cb*  
public synchronized int write(byte[] b,int nStart,int nLen) ULQ*cW&;?  
{ `wk#5[Y_  
int n = -1; C/ ;f)k<  
try{ H;IG\k6C  
oSavedFile.write(b,nStart,nLen); Ij{{Z;o3  
n = nLen; H!oP!rzEo  
} uCUQxFp  
catch(IOException e) X "1q$xwc  
{ Q1s`d?P/`  
e.printStackTrace (); H#wn3O  
} E!3W_:Bs  
}bix+/]  
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return n; $IB@|n  
} 1 ht4LRFi  
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} d!w32Y,.  
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/ ^!(rHf  
/* }$m_):t@@  
**SiteInfoBean.java VbA#D4;  
*/ _|H]X+|  
package NetFox; C{Aeud #5  
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public class SiteInfoBean { Ct #hl8b:  
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private String sSiteURL; //Site's URL T[ky7\  
private String sFilePath; //Saved File's Path Q"QrbU  
private String sFileName; //Saved File's Name <lv:mqV  
private int nSplitter; //Count of Splited Downloading File 8
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public SiteInfoBean() ?uh7m2l0D  
{//nSplitter的缺省值为5 5+,&9;'Y^  
//default value of nSplitter is 5 s
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this("","","",5); %;ny  
} E%/E%9-7\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Lqwc:%Y:_  
{ ?t?!)#X  
sSiteURL= sURL; &wLI:x5  
sFilePath = sPath; }ZR3  
sFileName = sName; gqGl>=.m  
this.nSplitter = nSpiltter; GT#iY*  
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} 97<Y. 0  
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public String getSSiteURL() h9SS o0]F  
{ ;~xkT'  
return sSiteURL; oh,
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} >/evL /  
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public void setSSiteURL(String value) 2nOQ48haT  
{ i[WTp??Uv  
sSiteURL = value; [Zgy,j\\  
} \XmtSfFC  
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public String getSFilePath() ,!u^E|24  
{ vhKeW(z  
return sFilePath; &/Tx@j^.C  
} e|]g?!  
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public void setSFilePath(String value) o$Hc5W([Z  
{ zg|yW6l)9  
sFilePath = value; N!Kd VDdT|  
} jZ.+b j >  
x{RTI#a.  
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public String getSFileName() q;Qpd]H  
{ y\)bx

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return sFileName; $F\&?B1.  
} b]CJf8'u  
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9$S2:2(G  
public void setSFileName(String value) )pJ}o&J  
{ d|DIqT~{W  
sFileName = value; [y>Q3UqN  
} ]FQ4v.7  
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public int getNSplitter() uCmdNY  
{ 2c9@n9Vx3a  
return nSplitter; 0-FwHDxw  
} j:U>V7Kn3~  
f~W.i]  
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public void setNSplitter(int nCount) C:gE   
{ 
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nSplitter = nCount; x-Xb4?{  
} 5nf|CQH6?  
} XwlUkw"q  
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/* w)DO"Z7  
**Utility.java ?;uzx7@F  
*/ /?2yo{Fg  
package NetFox; }qbz&%R  
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public class Utility { 0Dh a1[=  
$Q]`+:g*}  
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public Utility() ub.pJJlC  
{ sM~CP zMa  
hRc\&+#/  
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} )t)tk=R9N  
a$9UUH-|  
//线程睡眠 Td8'z'  
public static void sleep(int nSecond) -pX/Tt6  
{  ocL  
try{ Wy4v~]xd%  
Thread.sleep(nSecond); QC ]z--wu  
} mHw1n=B  
catch(Exception e) T 0^U ]C  
{ wl(}F^:/`  
e.printStackTrace (); 4b7}Sr=`  
}
}8x[  
} U76:F?MH  
X*FK6,Y|(  
//日志 I`5MAvP  
public static void log(String sMsg) *?\2Ohp  
{ Blaj07K  
System.err.println(sMsg); zRf]SZ(tO  
} /dWuHS  
;{HxY98Q  
+86\&y)
 
public static void log(int sMsg) (y(V,kXwa8  
{ #2u-L~n  
System.err.println(sMsg); *sL'6"#Cre  
}  NPf,9c;  
} ,[cWG)-  
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/* &;%+Hduc  
**TestMethod.java %f:'A%'Qb  
*/ u6B (f;  
package NetFox; ZE}m\|$  
'# (lq5 c  
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public class TestMethod { b<:s{f"t,  
xn6E f"  
[a+?z6qI\}  
public TestMethod() B /Dj2  
{ ///xx/weblogic60b2_win.exe `_<AZ{&&  
try{ ;q$<]X_S)}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L;BYPZR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Odbjl[>k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YjdH7.js  
fileFetch.start(); UejG$JyHP  
} gHox{*hb[  
catch(Exception e){e.printStackTrace ();} _@"Y3Lqi  
`w~ 9/sty  
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} 2\s-4H| q  
*[vf47)r!  
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public static void main(String[] args) c4; `3  
{ hs/nM"V  
new TestMethod(); H;$w^Tr  
} Z2 t0l%  
} $@K+yOq+u  
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