http断点续传简单实现（java)

/* ]#*S. r]  
**SiteFileFetch.java +91j 1?  
*/ <*'%Xgm  
package NetFox; HZDeQx`*s  
import java.io.*; vz1yH%~E  
import java.net.*; -fm1T|>#  
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public class SiteFileFetch extends Thread { N">4I)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]QbT%0  
long[] nStartPos; //开始位置 d[7B,l:RN  
long[] nEndPos; //结束位置 NZW)$c'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :Ou[LF.O  
long nFileLength; //文件长度 ,^K}_z\9f  
boolean bFirst = true; //是否第一次取文件 h%*@82DKK  
boolean bStop = false; //停止标志 %&[=%zc  
File tmpFile; //文件下载的临时信息 I)YUGA5  
DataOutputStream output; //输出到文件的输出流 cKM#0dq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )nM<qaI{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZCC T  
{ ;.'\8!j  
siteInfoBean = bean; H,q-*Kk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FMNT0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Svl;Ul  
if(tmpFile.exists ()) h
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{ /a7N:Z_Bz  
bFirst = false; E gD$A!6N8  
read_nPos(); r>;(\_@  
} Q*54!^l+_r  
else #9e2+5s  
{ [fZhfZ)<  
nStartPos = new long[bean.getNSplitter()]; #Y%(CI  
nEndPos = new long[bean.getNSplitter()]; ]]eI80u[  
} Tf{lH9ca$  
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} `P/87=h  
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public void run() ,~G:>q$ad  
{ Ov~vK\  
//获得文件长度 W!R7D%nX  
//分割文件 k!0vpps
 
//实例FileSplitterFetch !%/2^  
//启动FileSplitterFetch线程 AK//]   
//等待子线程返回 A)80qx:  
try{ 9WT{~PGj  
if(bFirst) Xk?Y  
{ r*kz`cJ  
nFileLength = getFileSize(); qS/ 'Kyp_  
if(nFileLength == -1) hH]oJ}H \  
{ <~hx ~"c  
System.err.println("File Length is not known!"); 5 D[`nU}  
} wJg&OQc9  
else if(nFileLength == -2) Zfc{}ius  
{ l{8t;!2t  
System.err.println("File is not access!"); z0 J:"M  
} *(o^w'5  
else tpQ
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{ <Q@{6  
for(int i=0;i<nStartPos.length;i++) gg&Dej2{  
{ G7k.YtW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Eyh(257  
} LM*m>n*  
for(int i=0;i<nEndPos.length-1;i++) 50^CILKo7  
{ 5|g#>sx>`q  
nEndPos = nStartPos[i+1]; 0Ci:w|J  
} g+QNIM>  
nEndPos[nEndPos.length-1] = nFileLength; 1>
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} (AT)w/  
} b4CXif  
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//启动子线程 oR}'I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q]DE\*@  
for(int i=0;i<nStartPos.length;i++) BFPy~5W  
{ )%bY2 pk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eo<=Q|nI&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @O| lA  
nStartPos,nEndPos,i); /H$/s=YU\U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *?!A  
fileSplitterFetch.start(); g.x]x#BC  
} 24I~{Qy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fYzZW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7Yly^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2rqYm6  
nEndPos = " + nFileLength); h"(HDnq  
// fileSplitterFetch[nPos.length-1].start(); TN.&FDqC9  
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//等待子线程结束 e2Df@8>  
//int count = 0; J-Wphc!m  
//是否结束while循环 QO3QR/Ww  
boolean breakWhile = false; S*a_  
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u =
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while(!bStop) > 72qi*0  
{ bS*oFm@u  
write_nPos(); u|8yV.=R  
Utility.sleep(500); [(/IV+  
breakWhile = true; "hXB_73)V  
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for(int i=0;i<nStartPos.length;i++) ^ ,yh38
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{ Hbi2amfBu  
if(!fileSplitterFetch.bDownOver) @(s"5
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{ 'E~[I"0  
breakWhile = false; 5E}~iC&  
break; 9 e0Oj3!B  
} +)-`$N  
} CD
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if(breakWhile) /]"2;e-s+  
break; \F8*HPM=*  
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//count++; |\S p IFH1  
//if(count>4) mLL?n)   
// siteStop(); pTk1iGfB  
} H| 1O>p&  
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\  
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System.err.println("文件下载结束！"); BjIKs~CT  
} 9?#L/  
catch(Exception e){e.printStackTrace ();} \t 04-  
} 6zJfsKf$  
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//获得文件长度 5cE
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public long getFileSize() JJ$q*  
{ uGMmS9v$ J  
int nFileLength = -1; W
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try{ )Y}8)/Pud  
URL url = new URL(siteInfoBean.getSSiteURL()); x)Ls(Xh+g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z/hgr|&}  
httpConnection.setRequestProperty("User-Agent","NetFox"); { |[n>k   
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int responseCode=httpConnection.getResponseCode(); wc#E:GJcK  
if(responseCode>=400) q2C._{ 0'  
{ Xv'5%o^i*  
processErrorCode(responseCode); o0'!u  
return -2; //-2 represent access is error yq2pg8%  
} H~Fb=.h]U  
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String sHeader; :v>Nz7SB  
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for(int i=1;;i++) w`$M}oX(  
{  F6\Hqv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GnzKDDH '  
//Utility.log(in.readLine()); ,_(AiQK  
sHeader=httpConnection.getHeaderFieldKey(i); o6[aP[~F  
if(sHeader!=null) ;9rS[$^$O  
{ 2)zAX"#
/  
if(sHeader.equals("Content-Length")) [R~`6  
{ .!pr0/9B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y:R!E *.L'  
break; awic9uMH  
} ~d072qUos  
} Lm{qFu  
else g VPtd[r  
break; y]e[fZ`L  
} (L3Etan4RE  
} rV0X*[]J>  
catch(IOException e){e.printStackTrace ();} W1T% Q88  
catch(Exception e){e.printStackTrace ();} 2`;&Uwt  
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Utility.log(nFileLength); +-*Ww5Zti  
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return nFileLength; t3// U#  
} +338z<'Z!  
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//保存下载信息（文件指针位置） CVy\']  
private void write_nPos() (/a#1Pd&  
{ +\
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try{ '=X)0
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output = new DataOutputStream(new FileOutputStream(tmpFile)); -/'_XR@1  
output.writeInt(nStartPos.length); L]kd.JJvy  
for(int i=0;i<nStartPos.length;i++) iX|K4.Pz{  
{ \~!!h.xR  
// output.writeLong(nPos); fR$_=WWN>h  
output.writeLong(fileSplitterFetch.nStartPos); z*FCd6X  
output.writeLong(fileSplitterFetch.nEndPos); ``?79MJ5  
} R ~ZcTY[8  
output.close(); l{o,"P"  
} Rl/5eE8  
catch(IOException e){e.printStackTrace ();} p.^qB]%  
catch(Exception e){e.printStackTrace ();} 2t,N9@u=UN  
} <c77GimD?  
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//读取保存的下载信息（文件指针位置） |8q:sr_  
private void read_nPos() j"F?^0aR,Q  
{ H-&T)  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {U'\2Ge<m  
int nCount = input.readInt(); 5(=5GkE)>  
nStartPos = new long[nCount]; bt{b%r  
nEndPos = new long[nCount]; 7M/v[dwL  
for(int i=0;i<nStartPos.length;i++) d@XXqCR<  
{ 9?XQB%44  
nStartPos = input.readLong(); ]?6Pt:N2  
nEndPos = input.readLong(); [eO^C  
} FMi:2.E  
input.close(); `+m:@0&L  
} 4`GOBX1b.y  
catch(IOException e){e.printStackTrace ();} N<PDQ  
catch(Exception e){e.printStackTrace ();} @xXVJWEU:  
} ;=p3L<~c`K  
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private void processErrorCode(int nErrorCode) ~ \]?5 nj  
{ w*M&@+3I  
System.err.println("Error Code : " + nErrorCode); (Z0_e&=*  
} V,h}l"  
~].?8C.>*  
)_YB8jUR-X  
//停止文件下载 4`B3Kt`o  
public void siteStop() T-LX>*  
{ @y'0_Y0-B  
bStop = true; lvsj4cT  
for(int i=0;i<nStartPos.length;i++) Q+oV? S3{  
fileSplitterFetch.splitterStop(); 16
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} njc-=o  
} bksv2@ar  
//负责部分文件的抓取 ,$} xPC  
**FileSplitterFetch.java %tMx48'N  
*/ :sQ>oNnz  
package NetFox; -.Blj<2ah  
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import java.io.*; 5Xf]j=_  
import java.net.*; $nb.[si\  
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public class FileSplitterFetch extends Thread { r'`7}@H*  
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String sURL; //File URL j^7A}fz  
long nStartPos; //File Snippet Start Position ;=7K*npT  
long nEndPos; //File Snippet End Position a'-u(Bw  
int nThreadID; //Thread's ID |UlG@Mn  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical 64mg:ed&  
FileAccessI fileAccessI = null; //File Access interface L R\LC6kM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $&=xw _  
{ l>MDCqV  
this.sURL = sURL; .L+XV y  
this.nStartPos = nStart; n>?D-)g  
this.nEndPos = nEnd; 4EHrd;|  
nThreadID = id; |mP};&b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z)S6f79`Q  
} 'f!U[Qatg  
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public void run() Kp6 @?  
{ R0}1:1}$Sn  
while(nStartPos < nEndPos && !bStop) 'w27Lt'V  
{ b,^Gj]7  
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try{ JwB'B  
URL url = new URL(sURL); dYwk
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6q\*{_CPB  
httpConnection.setRequestProperty("User-Agent","NetFox"); UWF \Vx*)b  
String sProperty = "bytes="+nStartPos+"-"; "bIb?e2h9G  
httpConnection.setRequestProperty("RANGE",sProperty); t&xoi7!$  
Utility.log(sProperty); %\v8FCb  
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InputStream input = httpConnection.getInputStream(); H; NV?CD  
//logResponseHead(httpConnection); uMEM7$o  
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byte[] b = new byte[1024]; cvaG[NF  
int nRead; 3l~+VBR_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y>8Q
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{ ${MzOi  
nStartPos += fileAccessI.write(b,0,nRead); wX0D^)NtF  
//if(nThreadID == 1) (T_-`N|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l!f_ +lv  
} `*3A7y  
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Utility.log("Thread " + nThreadID + " is over!");  E.h  
bDownOver = true; nbF<K?  
//nPos = fileAccessI.write (b,0,nRead); V 9Qt;]mQ  
} &KjMw:l  
catch(Exception e){e.printStackTrace ();} ]~aj  
} #4JMb#q0E  
} nzC *mPX8  
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//打印回应的头信息 hOwb   
public void logResponseHead(HttpURLConnection con) +@QrGY  
{ hzsQK_;S  
for(int i=1;;i++) `NNP<z+\  
{ MY,~leP&  
String header=con.getHeaderFieldKey(i); J<0{3pZY  
if(header!=null) s<zN`&t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -qc'J<*^4  
Utility.log(header+" : "+con.getHeaderField(header)); M0w Uis:`
 
else EB}B75)x  
break; Wx:v~/r  
} H~Uf2A)C  
} ]lwf6'  
9^
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public void splitterStop() 8\rca:cF   
{ wH ,PA:  
bStop = true; /x??J4r0  
} ^ 8}P_  
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} @D;K&:~|N  
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/* e3ZRL91c  
**FileAccess.java \6wltTW]#  
*//文件访问(定位，写) k*C69  
package NetFox; N|yA]dg[  
import java.io.*; lwQ!sH[M  
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public class FileAccessI implements Serializable{ g=\(%zfsxr  
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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 2H`r:x<Z-  
RandomAccessFile oSavedFile; b$'%)\('g  
long nPos; zeMV_rW~  
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public FileAccessI() throws IOException E:9RskI  
{ f!+d*9  
this("",0); -U2Su|:\N8  
} spA|[\Nl  
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public FileAccessI(String sName,long nPos) throws IOException aG7Lm2{c"  
{ 12 )  
oSavedFile = new RandomAccessFile(sName,"rw"); 'gN[LERT  
this.nPos = nPos; #X)DFAtb  
oSavedFile.seek(nPos); {Vu
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} z"<S$sDh  
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public synchronized int write(byte[] b,int nStart,int nLen) c\.)vH  
{ $~8gh>`]  
int n = -1; )P7oL.)  
try{ ?.,F3@W "  
oSavedFile.write(b,nStart,nLen); bzG vnaTt  
n = nLen; NkUY_rKPb  
} e[fld,s  
catch(IOException e) yHY2 SXm  
{ z/j*zU `  
e.printStackTrace (); @^0}wk  
} #IppjaPl8  
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return n; C,ldi"|  
} .P8m%$'N  
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} V~Guw[RA  
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/* yu#m6K  
**SiteInfoBean.java Zp/P/97p  
*/ #+i5'p(4  
package NetFox; cm!vuoB~~  
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public class SiteInfoBean { W<#Kam:8e  
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private String sSiteURL; //Site's URL 2n"-~'3\  
private String sFilePath; //Saved File's Path XcbEh  
private String sFileName; //Saved File's Name e0C_ NFS+  
private int nSplitter; //Count of Splited Downloading File {
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public SiteInfoBean() ,*[N_[  
{//nSplitter的缺省值为5 .Z`xNp  
//default value of nSplitter is 5 &/Gf@

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this("","","",5); {h|kx/4{m  
} 7#HSe#0J  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {Zs EYUP  
{ ;5|d[r}k3  
sSiteURL= sURL; ]:#W$9,WL  
sFilePath = sPath; uC]c`Ue  
sFileName = sName; nBd(pOe  
this.nSplitter = nSpiltter; TPj,
4&|  
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} \^cXmyQ<%  
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public String getSSiteURL() Q*f0YjH!  
{ dF&@q,  
return sSiteURL; G[d]t$f=  
} &[|Z
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public void setSSiteURL(String value) l?X)]1  
{ z2A,*|I  
sSiteURL = value;
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} !6 kn>447Y  
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public String getSFilePath() V_4=
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{ qP9`p4c8i  
return sFilePath; Fbw.Y6  
} a0k/R<4  
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public void setSFilePath(String value) qnU`Q{  
{ LmKY$~5P  
sFilePath = value; H:q;IYE+a  
} 2%-/}'G*  
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public String getSFileName() ,W$&OD  
{ ~'Korxa  
return sFileName; F\<{:wu   
} OL.{lKJ3DV  
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public void setSFileName(String value) ] $F%  
{ \O*W/9 +  
sFileName = value; z|<?=c2P  
} %y+v0.aWH+  
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public int getNSplitter() !^aJS'aq  
{ e=ry_@7  
return nSplitter; g]?QV2bX6  
} !3ji]q;uF  
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4@jX{{^6%  
public void setNSplitter(int nCount) 0>3Sn\gZ(  
{ :TP\pH7E  
nSplitter = nCount; 5[`f(;  
} i&L!?6 5-f  
} [n$6T  
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/* !dwa. lZ&X  
**Utility.java }4q1"iMlO  
*/ 76cT}l&.h8  
package NetFox; u y13SkW  
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public class Utility { 2zkOs:  
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public Utility() r
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{ N@I=X-7nh|  
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} OyIIJ!(  
be HEAQ  
//线程睡眠 zCmx1Djz  
public static void sleep(int nSecond) ;esOe\zjE  
{ (JT 273  
try{ V=H:`n3k  
Thread.sleep(nSecond); FlT5R*m  
} Fzy5k?R  
catch(Exception e) ;eW\41w  
{ se29IhS!e  
e.printStackTrace (); r"`7ezun:  
} QVkrhwp  
} $-paY
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G|z%T`!U1;  
//日志 @jKB[S;JSn  
public static void log(String sMsg) a:
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{ /])P{"v$^  
System.err.println(sMsg); BCh|^Pk  
} )Cd.1X8  
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public static void log(int sMsg) rbrh;\<jM  
{ ~re~Ys  
System.err.println(sMsg); #g<6ISuf  
} _Sl3)  
} Yw_!40`  
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/* dj{~!}  
**TestMethod.java KCnm_4  
*/ rl]K:8*  
package NetFox; ~nApRC)0  
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public class TestMethod { y2=yh30L0E  
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public TestMethod() aa{+,(  
{ ///xx/weblogic60b2_win.exe t8`wO+4@  
try{ `4g}(-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Zpz3?VM(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K|I<kA~!H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P~%+K
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fileFetch.start(); ABcB-V4  
} 2+ywl}9  
catch(Exception e){e.printStackTrace ();} }b/P\1#z  
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} JfmYr47Pv  
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public static void main(String[] args) ,
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{ ?:G 3U\M  
new TestMethod(); $m A2AI  
} r-.>3J  
} /aIGq/;Y+a  
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