http断点续传简单实现（java)

/* FT6CKsM"  
**SiteFileFetch.java 6U8esPs,  
*/ sj/k';#
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package NetFox; k -R"e  
import java.io.*;  C&qo$C  
import java.net.*; mUP!jTF  
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public class SiteFileFetch extends Thread { .,qh,m\Fo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4l*cX1!  
long[] nStartPos; //开始位置 )ej1)RU"  
long[] nEndPos; //结束位置 H"w;~;h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;Qt/(/  
long nFileLength; //文件长度 Oj%5FUP~[%  
boolean bFirst = true; //是否第一次取文件 'Y ,2CN  
boolean bStop = false; //停止标志 hVB(*WA^D  
File tmpFile; //文件下载的临时信息 ,Il) tH  
DataOutputStream output; //输出到文件的输出流 QwG_-  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
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public SiteFileFetch(SiteInfoBean bean) throws IOException )mN/e+/Lu  
{ +(:Qf+:  
siteInfoBean = bean; =EYgck;)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y{dX[^[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7n8
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if(tmpFile.exists ()) 4,:I{P_>6B  
{ kGnT4R*E  
bFirst = false; q#8\BOTP |  
read_nPos(); *u|1Z%XO  
} PPG+~.7  
else |n;);T(  
{ a;; Es  
nStartPos = new long[bean.getNSplitter()]; 9\Ff z&  
nEndPos = new long[bean.getNSplitter()]; ~QUNR?h  
} 4*f+np  
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} Io
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public void run() (m Yi  
{ *rxYal4ad  
//获得文件长度 g.62XZF@  
//分割文件 qk^/&j  
//实例FileSplitterFetch fsEQ4xN'  
//启动FileSplitterFetch线程 E6xdPjoWy  
//等待子线程返回 hfbu+w):  
try{ SfY 5Xgp  
if(bFirst) G,<d;:  
{
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nFileLength = getFileSize(); 5/U{b5  
if(nFileLength == -1) [8Z#HjhQ  
{ c}S<<LR  
System.err.println("File Length is not known!"); +C7W2!I[G2  
} vY.VFEP/  
else if(nFileLength == -2) dJrUcZBr  
{ CflyK@  
System.err.println("File is not access!"); ^uw]/H3?L  
} bnvY2-O6  
else s"$K2k;J  
{ F"M/gy  
for(int i=0;i<nStartPos.length;i++) jp4-w(  
{ hop| xtai;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XGe;v~L  
} @C=gMn.E  
for(int i=0;i<nEndPos.length-1;i++) &k
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{ AH'3 5Kf)  
nEndPos = nStartPos[i+1]; byt$Wqdl  
} o>+mw|{  
nEndPos[nEndPos.length-1] = nFileLength; FY)]yz  
} 3]}RjOTU  
} M?('VOy)  
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//启动子线程 4DL2 A;T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a0A=R5_  
for(int i=0;i<nStartPos.length;i++) * Z)j"i  
{ SQ+r'g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1VG]|6f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >;j&]]-&  
nStartPos,nEndPos,i); W79.Nj2`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |${ImP  
fileSplitterFetch.start(); `?l /HUw  
} yXEI%2~)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <f.Eog  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {gu3KV  
nEndPos = " + nFileLength); w9"~NK8xzM  
// fileSplitterFetch[nPos.length-1].start(); ;{R;lF,  
ZO<\rX (  
OA}; pQ9QN  
//等待子线程结束 Ke:EL;*8k  
//int count = 0; dOaCdnd~  
//是否结束while循环 sL\ {.ad5  
boolean breakWhile = false; 6v%ePFul  
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while(!bStop) %B1TN#KoT  
{ <0~1  
write_nPos(); [x=(:soEqC  
Utility.sleep(500); sHPeAa22  
breakWhile = true; d>MDC . j  
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for(int i=0;i<nStartPos.length;i++) \=|=(kt)  
{ vQ2{+5!|  
if(!fileSplitterFetch.bDownOver) Rq?t=7fX)  
{ /d"@$+  
breakWhile = false; g$Vr9MH  
break; V)5,E>;EN  
} SEi\H$!  
} Q*'OY~  
if(breakWhile) ;0 +Dx~  
break; 0/!0W%f[}  
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//count++; p9\*n5{  
//if(count>4) IW@phKz  
// siteStop(); {w"Cr0F,  
} }$uwAevP{y  
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System.err.println("文件下载结束！"); \WdSj  
} x\:KfYr4Y;  
catch(Exception e){e.printStackTrace ();} v,~fG
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} +`mI\+y,  
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//获得文件长度 fJk'5kv  
public long getFileSize() Sj/v:  
{ F9las#\J  
int nFileLength = -1; s?9Y3]&+&M  
try{ #k>A,  
URL url = new URL(siteInfoBean.getSSiteURL()); Bzt:9hr6BO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qJonzFp7  
httpConnection.setRequestProperty("User-Agent","NetFox");  ZpBP#Y*  
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int responseCode=httpConnection.getResponseCode(); Q]K$yo  
if(responseCode>=400) Ayn$,  
{ eFA,xzp  
processErrorCode(responseCode); ./'d^9{  
return -2; //-2 represent access is error 5X5UUdTM  
} @y * TVy  
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String sHeader; !SnLvW89Z  
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for(int i=1;;i++) 4 540Lw'A  
{ ${wp}<u_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =_@) KWeX$  
//Utility.log(in.readLine()); ug;\`.nT^  
sHeader=httpConnection.getHeaderFieldKey(i); ;
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if(sHeader!=null) -^7 $HD  
{ 8uW%
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if(sHeader.equals("Content-Length")) W*(- *\1[  
{ 9OY ao  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q j9q  
break; 61gyx6v  
} &^ s8V]^  
} K@Q%NK,  
else *O[/- p&7  
break; @8A[HP  
} O%F*i2I:+k  
} ouFKqRs;  
catch(IOException e){e.printStackTrace ();} <1*\ ~CX  
catch(Exception e){e.printStackTrace ();} R4k+.hR  
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Utility.log(nFileLength); :mf&,?  
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return nFileLength; 3qH1\  
} `/!FZh<  
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//保存下载信息（文件指针位置） utC^wA5U~  
private void write_nPos() 7&%#bMnw  
{ l2dj GZk  
try{ cF
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output = new DataOutputStream(new FileOutputStream(tmpFile)); C6@*l~j  
output.writeInt(nStartPos.length); ^mC,Z+!  
for(int i=0;i<nStartPos.length;i++) L8NZU*"  
{ FDGG$z?>m  
// output.writeLong(nPos); !g=b=YK  
output.writeLong(fileSplitterFetch.nStartPos); s&$e}yxVO  
output.writeLong(fileSplitterFetch.nEndPos); = 8y,7u)  
} jWh)bsqI!  
output.close(); YH^@8   
} Q0x?OL]A  
catch(IOException e){e.printStackTrace ();} dI
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catch(Exception e){e.printStackTrace ();} F`{O  
} 0,.|-OZ  
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//读取保存的下载信息（文件指针位置） 2*Pk1vrI  
private void read_nPos() !u  .n  
{ Iij$ce`nx  
try{ O2="'w'kR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :7dc;WdM  
int nCount = input.readInt(); '}bmDb*  
nStartPos = new long[nCount]; + DE/DR:  
nEndPos = new long[nCount]; 8xhx*A  
for(int i=0;i<nStartPos.length;i++) H/;AlN|!  
{ <$25kb R5K  
nStartPos = input.readLong(); Xrpvq(]  
nEndPos = input.readLong(); j*4:4B%  
} 5tLb o  
input.close(); @>J(1{m=Gy  
} 3/]FT#l]i  
catch(IOException e){e.printStackTrace ();} y"U)&1 c%  
catch(Exception e){e.printStackTrace ();} b^ [ z'  
} $MfRw
  
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private void processErrorCode(int nErrorCode) 5dD8s-;^T  
{ /<(-lbq,  
System.err.println("Error Code : " + nErrorCode); KHJ wCv  
} h/8p2Mrqi  
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//停止文件下载 K~S*<
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public void siteStop() ]fU&?z#  
{ H~>8q~o]  
bStop = true; PCV#O63[  
for(int i=0;i<nStartPos.length;i++) Q&^\YgkCf  
fileSplitterFetch.splitterStop(); (pd~ 2!;C  
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} {Ja(+NQ  
} e+4Eiv  
//负责部分文件的抓取 p0]\QM l1  
**FileSplitterFetch.java EYCZuJxv  
*/ EVw{G<  
package NetFox; D<<q5gG  
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import java.io.*; V7p hD3Y  
import java.net.*; <8Nr;96
IA  
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public class FileSplitterFetch extends Thread { ;c DMcKKIA  
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String sURL; //File URL &rPAW V'v  
long nStartPos; //File Snippet Start Position 6
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long nEndPos; //File Snippet End Position _9p79S<+  
int nThreadID; //Thread's ID d"Wuu1tEY  
boolean bDownOver = false; //Downing is over NuUiW*|`7  
boolean bStop = false; //Stop identical Q6e7Z-8  
FileAccessI fileAccessI = null; //File Access interface Cg`lQYU  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException - _6`0  
{ F[!%,-*  
this.sURL = sURL; tm2
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this.nStartPos = nStart; ,Oy$q~.  
this.nEndPos = nEnd; EBz4k)@m  
nThreadID = id; k)X\z@I'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S7#dyAX8  
} j|N<6GSke  
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public void run() ~UNha/nt  
{ bqp^\yu-E  
while(nStartPos < nEndPos && !bStop) $8AW  
{ }Q]-Y :  
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try{ ,9_O4O%  
URL url = new URL(sURL); wAX;)PLg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <p/2hHfiD  
httpConnection.setRequestProperty("User-Agent","NetFox");  .P")S|  
String sProperty = "bytes="+nStartPos+"-"; YhfQpe  
httpConnection.setRequestProperty("RANGE",sProperty); 4dLnX3 v  
Utility.log(sProperty); /`DKX }  
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InputStream input = httpConnection.getInputStream(); K9p<PL
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//logResponseHead(httpConnection); -zqpjxU:  
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byte[] b = new byte[1024]; BnGoB`n  
int nRead; ]vn*eqd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SE6(3f$  
{ 1TR+p? "  
nStartPos += fileAccessI.write(b,0,nRead); /~f[>#  
//if(nThreadID == 1) lBs-u h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X"r.*fb;N  
} YZSQOLN{  
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Utility.log("Thread " + nThreadID + " is over!"); _od /)#  
bDownOver = true; _;Xlw{FN^  
//nPos = fileAccessI.write (b,0,nRead); )z18:C3  
} @U1|?~M%s  
catch(Exception e){e.printStackTrace ();} r=vY-p  
} 5$HG#2"Kb#  
} L%Rw]=v}v  
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//打印回应的头信息 I9>vm]  
public void logResponseHead(HttpURLConnection con) &0%Zb~ts  
{ F --b,,  
for(int i=1;;i++) j%-Ems*H  
{ ~ho,bwJM[T  
String header=con.getHeaderFieldKey(i); F8{gJaP x  
if(header!=null) {Bk` Zlki  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3\ Mt+!1{  
Utility.log(header+" : "+con.getHeaderField(header)); <HN+pi  
else yI#qkl-  
break; jl(D;JnF  
} E QU@';~8  
} fDplYn#  
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public void splitterStop() }5(_gYr  
{ Cb? !+U  
bStop = true; ,Ww}xmq1H  
} <PuY"-`/Oc  
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} lnyq%T[^  
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/* ?hc=w2Ci  
**FileAccess.java )V[j~uOU)]  
*//文件访问(定位，写) ;nW;M 4{  
package NetFox; 7qO
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import java.io.*; Y,Z$U| U  
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public class FileAccessI implements Serializable{  ~,&8)1  
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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 Ib{l$#  
RandomAccessFile oSavedFile; gL&w:_  
long nPos; 3))R91I  
/4pYhJ8S  
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public FileAccessI() throws IOException H+Bon=$cE!  
{ Ji9o0YR  
this("",0); V'W*'wo  
} S}U_uZ$b  
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public FileAccessI(String sName,long nPos) throws IOException ciml:"nQ  
{ wdBBx\FP  
oSavedFile = new RandomAccessFile(sName,"rw"); 2ns,q0I A  
this.nPos = nPos; BV>9U5  
oSavedFile.seek(nPos); ~zac.:a8  
} i*mU<:t  
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),B/NZ/-  
public synchronized int write(byte[] b,int nStart,int nLen) ^[m-PS(
 
{ \M@IKE  
int n = -1; '*rS,y  
try{ K g#Bg##  
oSavedFile.write(b,nStart,nLen); Aqf9
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n = nLen; 8WP"~Js!  
} ^K1mh9O  
catch(IOException e) xPUukmG:B  
{ NJr)f  
e.printStackTrace (); S>
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} 
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return n; Wc+(xk  
} :KX*j$5U  
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} ,z#D[5
  
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/* 5p!{#r6m  
**SiteInfoBean.java NwYQ6VEA  
*/ DeF`#a0E  
package NetFox; Mpw]dYM  
WK*tXc_[b  

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public class SiteInfoBean { ,#,K_oz  
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private String sSiteURL; //Site's URL J0R{|]W8  
private String sFilePath; //Saved File's Path 8w[O%  
private String sFileName; //Saved File's Name >@bU8}rT  
private int nSplitter; //Count of Splited Downloading File +<xQ
F  
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public SiteInfoBean() e> 9X  
{//nSplitter的缺省值为5 7lwI]/ZH*  
//default value of nSplitter is 5 ti9e(Jt!O  
this("","","",5); DIQ30(MS  
} DU"Gz!X]Jd  
2RNee@!JJP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <#M1I!R  
{ Y&=DjKoVh  
sSiteURL= sURL; R||$Rfe  
sFilePath = sPath; M61Nl)|mx&  
sFileName = sName; lc5(^~  
this.nSplitter = nSpiltter; $X)|`$#pL#  
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]JGq{I>%+6  
} jsgDJ}  
R#~l
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*.wj3'wV  
public String getSSiteURL() :EHk]Hkz  
{ DpmAB.  
return sSiteURL; oO?+2pTQV  
} Q!IqvmO  
l
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public void setSSiteURL(String value) ,|\\C6s  
{ `g1?Q4h  
sSiteURL = value; BRu}"29  
} H'!OEZ  
'*Dp2Y{7  
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public String getSFilePath() *(r9c(xa  
{ ERK{smL  
return sFilePath; UJL'4 t/  
} 5D7 L)>  
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7#UJ444b~  
public void setSFilePath(String value) r 56~s5A  
{ kkHK~(>G  
sFilePath = value; [vb#W!M&|  
} &${| o@  
o?M;f\Fy  
TeZu*c  
public String getSFileName() h2mHbe43  
{ \oxf_4X  
return sFileName; ShV_8F z  
} Lhg  
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public void setSFileName(String value) (HeSL),1  
{ Pr%KcR ;  
sFileName = value; w0$+v/  
} Gb[J3:.  
#G
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public int getNSplitter() pl,XS6mB  
{ j&S.k  
return nSplitter; SbL7e#!!  
} TK'y-5W  
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public void setNSplitter(int nCount) *tpS6{4=#7  
{ A9ld9R  
nSplitter = nCount; 9{SzE /[  
} c1_Z
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} @zw&-b:qI  
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/* ,s}&|+ '"  
**Utility.java uInI{>  
*/ (?,jnnub  
package NetFox; ESIJ QM-[+  
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public class Utility { 2'W#x  
q%A>q;l:  
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public Utility() Rd;t}E$  
{ PW"?*~&  
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} &l-d_dh  
HtE^7i*_  
//线程睡眠 438r]f?0|{  
public static void sleep(int nSecond) DrBkR`a?  
{ jc>B^mqx  
try{ nHXPEbq-g  
Thread.sleep(nSecond); /:\27n  
} dKDCJt]t  
catch(Exception e) W>{&" 5  
{ >N`, 3;Z  
e.printStackTrace (); 0%\fm W j  
} }4c$_  
} 0?I  
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//日志 # E8?2]  
public static void log(String sMsg) +W-b3R:1>  
{ "=40%j0  
System.err.println(sMsg); 5mudww`  
} 0$yHO2 f  
2.{<C.BK{  
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public static void log(int sMsg) 6oq^n s-  
{ l_2l/ff9  
System.err.println(sMsg); L4u.cHJ}0  
} -s0J8b  
} b=WkRj  
kwS[,Qy\  
[CV0sYEA  
/* |D'!.$7%  
**TestMethod.java F$:mGyl5_  
*/ 7n;a_Z0s$  
package NetFox; wc}x [cS  
}+[!h=Bx  
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public class TestMethod { l:#'i`;  
slr>6o%W`  
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public TestMethod() chuJj IY  
{ ///xx/weblogic60b2_win.exe %.uN|o&n  
try{ 1T,Bd!g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %>O}bdSf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !HXsxNe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iztF  
fileFetch.start(); %2G3+T8*x  
} %md9ou`  
catch(Exception e){e.printStackTrace ();} % 1<@p%y/  
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]8cD,NS  
} F?y C=  
r|3u]rt  
VWCC(YRU|$  
public static void main(String[] args) bhZ5-wo4%  
{ |NjyO>@Pa  
new TestMethod(); wlP% U  
} e6T?2`5P  
} =7-kD3  
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