http断点续传简单实现（java)

/* sINQ?4_8T  
**SiteFileFetch.java T9nb ~P[  
*/ 5XKTb  
package NetFox; \,#$,dUXD  
import java.io.*; l\UjvG  
import java.net.*;  mwAN9<o  
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public class SiteFileFetch extends Thread { b>-DX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean QG5WsuT  
long[] nStartPos; //开始位置 <*(Z}p  
long[] nEndPos; //结束位置 Kip&YB%rk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 luoQ#1F?sl  
long nFileLength; //文件长度 Aw#<:6-  
boolean bFirst = true; //是否第一次取文件 _uIS[%4g  
boolean bStop = false; //停止标志 FZi@h  
File tmpFile; //文件下载的临时信息 Sm'Tz&!  
DataOutputStream output; //输出到文件的输出流 vIV|y>;g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException $bTtD<a  
{ [IYVrT&C'  
siteInfoBean = bean; 2"ax*MQH<^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +z;*r8d<X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _T\~%  
if(tmpFile.exists ()) (nqry[g&  
{ *ID=X!v  
bFirst = false; UoT`/.  
read_nPos(); ]\pi!oa  
} rFXdxRP;M  
else ^')8-aF .  
{ rW?WdEg  
nStartPos = new long[bean.getNSplitter()]; j9 nw,x
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nEndPos = new long[bean.getNSplitter()]; <%)vl P#@  
} L
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} m{q'RAw  
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public void run() n>
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{ eRMN=qP.q  
//获得文件长度 ^j}C]cq{Xg  
//分割文件 F-m%d@P&X  
//实例FileSplitterFetch !rnjmc  
//启动FileSplitterFetch线程 YmV/[{  
//等待子线程返回 Hx.|5n,5  
try{ 9X*Nk~}Y  
if(bFirst) hr vTFJ  
{ &=@{`2&  
nFileLength = getFileSize(); zD{]3pg  
if(nFileLength == -1) 4(Lmjue]?  
{ si0}b~t  
System.err.println("File Length is not known!"); wps/{h,  
}
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else if(nFileLength == -2) x3O%W?5  
{ *6}M.`.-  
System.err.println("File is not access!"); rS1gFGrj  
} ('&lAn  
else bn*:Bn1  
{ gVG^R02#<k  
for(int i=0;i<nStartPos.length;i++) -`L`kL<  
{ l(>6Yq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a{8a[z  
} "| '~y}v_  
for(int i=0;i<nEndPos.length-1;i++) dseI~}  
{ ZLQmEF[>  
nEndPos = nStartPos[i+1]; 3&-rOc
 
} ^to*ET{0  
nEndPos[nEndPos.length-1] = nFileLength; PxKBcx4o`  
} aT0~C.vT  
} 2C S9v  
un "I  
LK'(OZ  
//启动子线程 H{}&|;0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E*'YxI  
for(int i=0;i<nStartPos.length;i++)  Zmu  
{ B}"R@;N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i%i~qTN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), opa/
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nStartPos,nEndPos,i); yy3rh(ea  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I!/32* s1t  
fileSplitterFetch.start(); YmljHQP  
} O nXo0PV/(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )LP'
4*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", j7!u;K^c  
nEndPos = " + nFileLength); A]bb*a1  
// fileSplitterFetch[nPos.length-1].start(); 8qe[x\,"8  
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//等待子线程结束 5EtR>Pc  
//int count = 0; =3(v4E':5  
//是否结束while循环 .tRm1&Qi  
boolean breakWhile = false; xkSXKR  
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while(!bStop) kK5&?)3Y:  
{ fN2Sio:  
write_nPos(); 4?pb
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Utility.sleep(500); Jh+;+"  
breakWhile = true; 24wDnDyh  
pm O9mWq   
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for(int i=0;i<nStartPos.length;i++) vQ< ~-E  
{
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if(!fileSplitterFetch.bDownOver) 'o&d!  
{ S*l/ Sa@  
breakWhile = false; lT[,w9$  
break; ;@;aeu  
} ^wy  
} QSaDa@OV  
if(breakWhile) 75\ZD-{T:  
break; y[McdlH m  
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2$JZ(qnN  
//count++; hj];a,Br&  
//if(count>4) A"*=K;u/|m  
// siteStop(); >Tf}aI+  
} G2`YZ\  
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System.err.println("文件下载结束！"); ykQb;ZP8jh  
} `}Y)l:G*g  
catch(Exception e){e.printStackTrace ();} AE~zmtW  
} )WvKRp r  
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//获得文件长度 )?{<Tt@  
public long getFileSize()
J`g5Qn@S  
{ xOkdu
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int nFileLength = -1; D5"5`w=C  
try{ &[yC M!  
URL url = new URL(siteInfoBean.getSSiteURL()); :'DX M{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IJf%OA>v  
httpConnection.setRequestProperty("User-Agent","NetFox"); &r[f ;|o  
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int responseCode=httpConnection.getResponseCode(); rl.K{Uad  
if(responseCode>=400) | V(sCF  
{ M8H hjoo  
processErrorCode(responseCode); ]I*RuDv}  
return -2; //-2 represent access is error k_t|) J  
} aQoB1qd8  
72$S'O%,0  
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String sHeader; fDr$Wcd~  
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hT^&*}G  
for(int i=1;;i++) C2<TR PT  
{ .qE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7c_2.T@4  
//Utility.log(in.readLine()); r2:{r`ocM  
sHeader=httpConnection.getHeaderFieldKey(i); 8YZ9  
if(sHeader!=null) cK|Uwzifd  
{ 1tbA-+  
if(sHeader.equals("Content-Length")) pCkMm)2g!  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0=,Nz  
break; QYH#WrIVx  
} { {?-& yA  
} B-g uz  
else SB%D%Zx6'%  
break; X!g
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} 4lPO*:/  
} e,Cc.T\o  
catch(IOException e){e.printStackTrace ();} /@ emE0  
catch(Exception e){e.printStackTrace ();} 3^KR{N p  
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Utility.log(nFileLength); [%^0L~:  
((Av3{05H&  
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return nFileLength; wHbmK  
} $mK;{9Z  
6}Y==GPt  
*& w/*h$!  
//保存下载信息（文件指针位置） e<+)IW:  
private void write_nPos() nHF66,7t  
{ RQ0^ 1 R  
try{ A*BN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QcWg  
output.writeInt(nStartPos.length); @@@}FV&  
for(int i=0;i<nStartPos.length;i++) !{,2uQXe  
{ 7x.j:{2  
// output.writeLong(nPos); yVVyWte,  
output.writeLong(fileSplitterFetch.nStartPos); 0(o2<d7  
output.writeLong(fileSplitterFetch.nEndPos); $<nD-4p  
} O!>#q4&]  
output.close(); xVsI#`<a  
} h% >ZN-K)  
catch(IOException e){e.printStackTrace ();} #Ey_.4S  
catch(Exception e){e.printStackTrace ();} LawE3CD  
} tJ\v>s-f  
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//读取保存的下载信息（文件指针位置） Wlg1t~1=  
private void read_nPos() zvGncjMkC  
{ #e=E  
try{ 7 2i&-`&4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1 jLQij  
int nCount = input.readInt(); L_T+KaQCH  
nStartPos = new long[nCount]; |;:Kn*0/]  
nEndPos = new long[nCount]; :CqR1_n%  
for(int i=0;i<nStartPos.length;i++) "%Ief4  
{ w15a~\Qu  
nStartPos = input.readLong(); J:)ml  
nEndPos = input.readLong(); i<$?rB!i<1  
} t"9r`0>  
input.close(); +9]t]Vrw  
} ?*UWg[  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} kbvF 9#  
} -+i7T^@|  
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private void processErrorCode(int nErrorCode) HoX={^aG%  
{ S -,$ (  
System.err.println("Error Code : " + nErrorCode); djoP`r  
} 'w1ll9O  
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A|PZ<WAY  
//停止文件下载 %qqCpg4  
public void siteStop() ts@w9|  
{ V:t{mu5j  
bStop = true; 8LF=l1=~  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); [OPF3W3z  
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} )l(DtU!E  
} nm_ta
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//负责部分文件的抓取 g`Q!5WK*  
**FileSplitterFetch.java 89KFZ[.}]  
*/ 3A0Qjj=  
package NetFox; g0QYBrp  
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import java.io.*; d~6UJ
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import java.net.*; N/
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public class FileSplitterFetch extends Thread {  6shN%  
;P}007;  
} gwfe H
 
String sURL; //File URL JoG(Nk
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long nStartPos; //File Snippet Start Position yW*,Llb5  
long nEndPos; //File Snippet End Position vV=rBO0a?  
int nThreadID; //Thread's ID Piw i  
boolean bDownOver = false; //Downing is over GBBp1i  
boolean bStop = false; //Stop identical sUQ Q/F6  
FileAccessI fileAccessI = null; //File Access interface ,*\s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V@y&n1?6  
{ 6~>h;wC  
this.sURL = sURL;
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this.nStartPos = nStart; .F%jbnKd_  
this.nEndPos = nEnd; Hj1?c,mo4  
nThreadID = id; A|4 3W=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eNH9`Aa  
} #}Xsi&:XU  
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public void run() ]R!YRu  
{ u] G  
while(nStartPos < nEndPos && !bStop) `SZ-o{  
{ wi%ls8
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try{ Wwr  
URL url = new URL(sURL); A42!%>PB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ']sjW'~  
httpConnection.setRequestProperty("User-Agent","NetFox"); r}(mjC"o  
String sProperty = "bytes="+nStartPos+"-"; e%)MIAS0  
httpConnection.setRequestProperty("RANGE",sProperty); 6#qt%t%?D  
Utility.log(sProperty); B\aVE|~PB  
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InputStream input = httpConnection.getInputStream(); F|'u0JQ)$  
//logResponseHead(httpConnection); {,(iL8,^  
b>#=7;  
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byte[] b = new byte[1024]; De{ZQg)  
int nRead; C7AD1rl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {6
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{  8}AWU  
nStartPos += fileAccessI.write(b,0,nRead); ~>_UTI  
//if(nThreadID == 1) Brd9"M|d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zTPNQ0=|  
} .r-Zz3  
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Utility.log("Thread " + nThreadID + " is over!"); SjF(;0kC  
bDownOver = true; }7xcHVO8-  
//nPos = fileAccessI.write (b,0,nRead); H?ug-7k/  
} YRv96|c,  
catch(Exception e){e.printStackTrace ();} W|E %  
} 'mm>
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} #_K<-m%9  
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//打印回应的头信息 RED@|[Qh  
public void logResponseHead(HttpURLConnection con) H4T~Kv  
{ #,1)@[  
for(int i=1;;i++) <u],R.S)  
{ Bva2f:)K|  
String header=con.getHeaderFieldKey(i); sO(4F8cpU  
if(header!=null) <5#2^
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); nz#eJ  
Utility.log(header+" : "+con.getHeaderField(header));  T-+ uQ3  
else 'n\PS,[1R  
break; Hr7pcz/#l  
} L(k`1E  
} =:6B`,~C  
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public void splitterStop() >vYb'%02  
{ Bc-/s(/Eq  
bStop = true; kkMChe};5  
} f#7=N
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} ,Jn` qvmi  
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/* F~7TE91C  
**FileAccess.java 5DkEJk7a  
*//文件访问(定位，写) "3a}~J<g  
package NetFox; ?| 6sTu!  
import java.io.*; -okq=9  
F!4V!VWA}  
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public class FileAccessI implements Serializable{ $A/?evJi8R  
d%nX;w,   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1A#/70Mo  
RandomAccessFile oSavedFile; OQKc_z'"  
long nPos; wa`c3PQGu  
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public FileAccessI() throws IOException k\dPF@~Hvl  
{ :qAX9T'{t  
this("",0); % -+7=x  
} O?"uM>r  
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public FileAccessI(String sName,long nPos) throws IOException .Y8P6_  
{ cq3Z}Cp  
oSavedFile = new RandomAccessFile(sName,"rw"); S;D]
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this.nPos = nPos; TiG?r$6v%  
oSavedFile.seek(nPos); L 8;H_:~_'  
} a'n17d&  
d+ZXi'  
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public synchronized int write(byte[] b,int nStart,int nLen) 9Nx%Sdu  
{ I_N:j,Mx  
int n = -1; R?2H
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try{ 4PkKL/E  
oSavedFile.write(b,nStart,nLen); Q 8;JvCz  
n = nLen; Dfc% jWbA  
} x ju*zmu  
catch(IOException e) gX(Xj@=(&  
{ 0M&~;`W}  
e.printStackTrace (); 19
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} .5s^a.e'O  
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return n; Hi/[  
} V\e1NS  
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} PX2b(fR8_O  
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/* oR,zr  
**SiteInfoBean.java 5ug|crX  
*/ ;volBfv  
package NetFox; }; M@JMu,  
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public class SiteInfoBean { !y>up+cRjl  
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private String sSiteURL; //Site's URL XZ3fWcw[  
private String sFilePath; //Saved File's Path 6%:~.ZfN  
private String sFileName; //Saved File's Name ?$uF(>LD  
private int nSplitter; //Count of Splited Downloading File _Ex<VF u  
w:iMrQeJg  
r ?<kWR?w  
public SiteInfoBean() Gr)G-zE  
{//nSplitter的缺省值为5 \&ZEIAe  
//default value of nSplitter is 5 ka ;=%*7T  
this("","","",5); !
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} U /~uu  
q8;MPXSG3  
4`fV_H.8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4sRg+mMI  
{ }m%&|:PH  
sSiteURL= sURL; $/5\Hg1  
sFilePath = sPath; F< 5kcu#iL  
sFileName = sName; ;T8(byH ?  
this.nSplitter = nSpiltter; S#HeOPRL  
@'GPZpbvZ  
F?6Q(mRl  
} ~x+'-2A46  
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public String getSSiteURL() oSf`F1;)HQ  
{ ],~[^0  
return sSiteURL; -1NR]#P'  
} @g+v2(f2v  
iQT0%WaHl  
}~ N\A  
public void setSSiteURL(String value) Ea'jAIFPpO  
{ \/gf_R_GN  
sSiteURL = value; bb\XZ~)F  
} 3 |LRb/|  
84reyA  
.3XiL=^~Qp  
public String getSFilePath() rnp; R  
{ /0Qo(  
return sFilePath; *O@Zn  
} 4,h)<(d{  
,Shzew+  
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public void setSFilePath(String value) f8=qnY2j  
{ G(Hr*T%  
sFilePath = value; v.vkQQ0[9  
} m .(\u?J  
1OMaY5F  
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public String getSFileName() 3O1Lv2)_  
{ 2EN}"Du]mj  
return sFileName; Ui9;rh$1eU  
} I.|b:c xN  
;L#RFdh  
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public void setSFileName(String value) a}|<*!4zUQ  
{ 9IrCu?n9b  
sFileName = value; iC^G^~V+H  
} YGs'[On8  
%6^nb'l'C  
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public int getNSplitter() hNkv lk'Ui  
{ PVdN)tG5  
return nSplitter; ~)>.%`v&  
} ZGI<L  
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V>E7!LIn.  
public void setNSplitter(int nCount) c&wiTvRV  
{ w9RBT(u  
nSplitter = nCount; &+ PVY>q  
} %H&WihQ  
} =_g#I  
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/* 
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**Utility.java tl7:L>  
*/ ^;( dF<?'r  
package NetFox; 4b`Fi@J\  
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public class Utility { AcH!KbYf  
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n_ ?+QF  
public Utility() ,O-_Pv  
{ .m>Qlh  
 6GVAR  
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} M.Tp)ig\#  
DTo"{!  
//线程睡眠 wL>*WLfR  
public static void sleep(int nSecond) #2:?N8vz*  
{ Lp@Al#X55  
try{ !TY0;is  
Thread.sleep(nSecond); *b0z/6  
} z j#<X  
catch(Exception e) S Te8*=w  
{ F0zaA  
e.printStackTrace (); YPq:z"`-y4  
} .V0fbHYTJ  
} G?\eO&QG{"  
Ex*{iJ;\  
//日志 {}iS5[H]  
public static void log(String sMsg) u8|CeA  
{ I?%q`GyP5  
System.err.println(sMsg); Qy4Pw\  
} !v9`oL26  
$^czqA-&  
][V`ym-e  
public static void log(int sMsg) 0c!^=(  
{ KD+&5=Y  
System.err.println(sMsg); Bj><0 cNF  
} O\Z!7UQ$  
} B^zg#x#8  
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P_8!Gp  
/* Z02EE-
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**TestMethod.java xw_$1 S  
*/ SK@ p0:  
package NetFox; F:jtzy"  
9xw"NcL  
dBovcc  
public class TestMethod { 7^M$u\a)U  
r)Zk-!1  
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public TestMethod() %{:pBt:Z  
{ ///xx/weblogic60b2_win.exe h<$%y(lP  
try{ opN4@a7l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QLHEzEvf{/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <n~.X<6V'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P0hr=/h4  
fileFetch.start(); *kTp(*K/7`  
} BBV>QL  
catch(Exception e){e.printStackTrace ();} w,R6:*p5  
F9%+7Op^  
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} 2|B@s3a  
8<C@I/  
$MNJsc^n  
public static void main(String[] args) )Td{}vbIh  
{ .v'`TD).6  
new TestMethod(); NYG!\u\Rm  
} :5T=y @  
} ^*B@=  
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