http断点续传简单实现（java)

/* P%.9g  
**SiteFileFetch.java D
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*/ #~nI^ ggW  
package NetFox; =yk#z84<  
import java.io.*; .] 5&\  
import java.net.*; ))u$j4V  
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public class SiteFileFetch extends Thread { :x= ZvAvo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean RDk{;VED{  
long[] nStartPos; //开始位置 !dGy"-i$h  
long[] nEndPos; //结束位置 H`m|R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  Ws}u4t  
long nFileLength; //文件长度 =v1s@5;~  
boolean bFirst = true; //是否第一次取文件 Z5_MSPm  
boolean bStop = false; //停止标志 Kq{9:G  
File tmpFile; //文件下载的临时信息 BwrMRMq"  
DataOutputStream output; //输出到文件的输出流 /
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4d[:{/+Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException SbrBlP:G  
{ PJ9JRG7j  
siteInfoBean = bean; mbSJ}3c"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rQ.j$U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GXJJOy1"!  
if(tmpFile.exists ()) 6d`6=D:  
{ dorZ O2Uc  
bFirst = false; :!J!l u  
read_nPos(); '9H]SEw  
} |Ax~zk;  
else ,]1K^UeZ  
{ N
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nStartPos = new long[bean.getNSplitter()]; "P'
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nEndPos = new long[bean.getNSplitter()]; Jc:*X4-'  
} Q_qc_IcM y  
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} sf@g $  
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public void run() YjoN:z`b  
{ kMf]~EZ?  
//获得文件长度 /|P&{!  
//分割文件 $yI!YX&  
//实例FileSplitterFetch ZSU;>&>%v  
//启动FileSplitterFetch线程 n<y!@p^X  
//等待子线程返回 XM>ByfD{  
try{ pkM_ @K  
if(bFirst) sq\oatMw[  
{ 0ppZ~}&  
nFileLength = getFileSize(); LezM=om.  
if(nFileLength == -1) v.c2(w/P  
{ X+ h|s
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System.err.println("File Length is not known!"); iKs/8n  
} hd8:|_  
else if(nFileLength == -2) khyn4   
{ q;InFV3rv  
System.err.println("File is not access!"); vB#&XK.aW  
} /`Yp]l  
else 1#&*xF"  
{ NUX0=(k  
for(int i=0;i<nStartPos.length;i++) ?6; +.h\  
{ a)`b;]+9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K\`L>B. 1  
} }2|>Y[v2j  
for(int i=0;i<nEndPos.length-1;i++) =O<Ul~JRK  
{ F9^
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nEndPos = nStartPos[i+1]; %
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} w<|^i*  
nEndPos[nEndPos.length-1] = nFileLength; "nf.kj:>  
} {]n5h#c 5*  
} "Rf8#\Y/<  
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//启动子线程 
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3tMs613  
for(int i=0;i<nStartPos.length;i++) i<YatW~Pu  
{ zC\ pd#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .nJErC##  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IX7<  
nStartPos,nEndPos,i); NX4!G>v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L 5J=+k,  
fileSplitterFetch.start(); KDhr.P.~
  
} %fGS< W;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  yS_,lS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2M3.xUS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vd c k  
nEndPos = " + nFileLength); 7?:7}xb-  
// fileSplitterFetch[nPos.length-1].start(); 5P9hm[  
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//等待子线程结束 *Em 9R  
//int count = 0; u.YPb@  
//是否结束while循环 n_Px=s!1p@  
boolean breakWhile = false; qsk8#  
f^@`[MJj1C  
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while(!bStop) Z"<aS&GH  
{ US A!N  
write_nPos(); aL$m  
Utility.sleep(500); ;Oh4W<hH}  
breakWhile = true; WHk/Rg%<  
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for(int i=0;i<nStartPos.length;i++) 2cY7sE068  
{ 8aQ\Yx  
if(!fileSplitterFetch.bDownOver) {|c <8  
{ RbKAB8  
breakWhile = false; =PWh,lWS  
break; }\k"azQ`  
} FVNxjMm,  
} &2C6q04b  
if(breakWhile) B- =*"H?q  
break; Wu(6FQ`H  
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//count++; jU |0!]  
//if(count>4) 1A"h!;0  
// siteStop(); %p6"Sg*  
} ;A7
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System.err.println("文件下载结束！"); c-.t8X,5(~  
} "PK\;#[W|  
catch(Exception e){e.printStackTrace ();} teH $hd-q  
} Bh$hgf.C  
t"k6wv;Tq  
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//获得文件长度 7t=e"|^  
public long getFileSize() v*`$is+  
{ dmI,+hHtL  
int nFileLength = -1; W8+Daw1Nr  
try{ Se7NF@>9_  
URL url = new URL(siteInfoBean.getSSiteURL()); RO"c+|Py  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (~}IoQp>  
httpConnection.setRequestProperty("User-Agent","NetFox"); T8+A`z=tSb  
6KC.l}Y*  
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int responseCode=httpConnection.getResponseCode(); 8##-fv]  
if(responseCode>=400) LDqq'}qK6  
{ N
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processErrorCode(responseCode); f(~xdR))eh  
return -2; //-2 represent access is error EEFM1asJf  
} -02cI}e  
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String sHeader; :#W40rUb  
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 *X- 6]C  
for(int i=1;;i++) S~fURn  
{ 'lNy&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^*(*tS|M  
//Utility.log(in.readLine()); YCZl1ry:V=  
sHeader=httpConnection.getHeaderFieldKey(i); (PAkKY}  
if(sHeader!=null) 2>BWu  
{ ))f%3_H  
if(sHeader.equals("Content-Length")) d#E]>:w
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{ (8DJ
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m`luMt9  
break; =>nrU8x  
} 1sp>UBG  
} HnU; N S3J  
else &5>R>rnB  
break; [r,a0s  
} C-!!1-Eq?:  
} tSX<^VER7  
catch(IOException e){e.printStackTrace ();} Pf&\2_H3s9  
catch(Exception e){e.printStackTrace ();} %xZYIYKf  
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Utility.log(nFileLength); ( HCB\!g  
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return nFileLength; qgREkb0  
} V5w00s5?%  
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//保存下载信息（文件指针位置） gzfs9e  
private void write_nPos() EC(,-sz\Z  
{ On x[}x  
try{ So>P)d$8+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A9Cq(L_H  
output.writeInt(nStartPos.length); sf{rs*bgp  
for(int i=0;i<nStartPos.length;i++) gc``z9@Xg
 
{ Co[fq3iX#  
// output.writeLong(nPos); $n_'#m2LE  
output.writeLong(fileSplitterFetch.nStartPos); WJH-~,u  
output.writeLong(fileSplitterFetch.nEndPos); J2A+x\{<  
} XaT9`L<  
output.close(); hBb&-/  
} Ln6\Iis  
catch(IOException e){e.printStackTrace ();} fik*-$V`  
catch(Exception e){e.printStackTrace ();} eeKErpj8A  
} DmDsn  
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//读取保存的下载信息（文件指针位置） /^_~NF#  
private void read_nPos() UcaLi&  
{ X!=E1TL  
try{ b4NUx)%ln  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wp2b*B=-  
int nCount = input.readInt(); -+vA9,pI  
nStartPos = new long[nCount]; :[icd2JCw]  
nEndPos = new long[nCount]; fTQ_miAlP  
for(int i=0;i<nStartPos.length;i++) ;. jnRPo";  
{ Ns?qLSN  
nStartPos = input.readLong(); zadn`B#2  
nEndPos = input.readLong(); dnRS$$9#  
} K)NB{8 _  
input.close(); M0Eq 7:Ba  
} )6K Q"*  
catch(IOException e){e.printStackTrace ();} P .I<.e  
catch(Exception e){e.printStackTrace ();} _i@{:v  
} w[`2t{^j  
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private void processErrorCode(int nErrorCode) SePPI.n  
{ [!^Q_O  
System.err.println("Error Code : " + nErrorCode); Af*e:}}  
} ii0{$}eoh  
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//停止文件下载 ZkbaUIQ  
public void siteStop() >j5,Z]  
{ lrn3yDkR?  
bStop = true; q. i2BoOd  
for(int i=0;i<nStartPos.length;i++) DV={bcQ  
fileSplitterFetch.splitterStop(); x#wkODLqi  
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} E;$;
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} I+qg'mo  
//负责部分文件的抓取 /(/Z~J[  
**FileSplitterFetch.java ,`4chD  
*/ pKSn 3-A  
package NetFox; 2Fi~GY_  
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import java.io.*; Y|'0bujr  
import java.net.*; bfjC:"!H  
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public class FileSplitterFetch extends Thread { U;o$=,_p  
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String sURL; //File URL 79DzrLu  
long nStartPos; //File Snippet Start Position o'oA.'ul  
long nEndPos; //File Snippet End Position E_fH,YJ?9  
int nThreadID; //Thread's ID h8nJt>h  
boolean bDownOver = false; //Downing is over _*tU.x|DP  
boolean bStop = false; //Stop identical ]lT8Z-h@  
FileAccessI fileAccessI = null; //File Access interface {}sF?wZf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4tQ~Z6Jn;  
{ JJIlR{WY_  
this.sURL = sURL; Q9i&]V[`  
this.nStartPos = nStart; .Y
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this.nEndPos = nEnd; d4#CZv[g/  
nThreadID = id; &d
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 p`dH4y]D  
} 3"*tP+H  
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public void run() $ \yZ;Z:  
{ uwL^Tq}Yh  
while(nStartPos < nEndPos && !bStop) mp!S<m  
{ S7B7'[ru  
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try{ d@0p<at>~  
URL url = new URL(sURL); ?Iin/<y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3R}O3#l
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httpConnection.setRequestProperty("User-Agent","NetFox"); |;(95  
String sProperty = "bytes="+nStartPos+"-"; J1s~w`,  
httpConnection.setRequestProperty("RANGE",sProperty); 6YHQ/#'G~  
Utility.log(sProperty); 2l4*6rYa(  
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InputStream input = httpConnection.getInputStream(); [$Dzf<0  
//logResponseHead(httpConnection); 8t)?$j$  
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|3bCq(ZR\P  
byte[] b = new byte[1024]; %W(/W9B$/F  
int nRead; M+L8~BD@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ? PI2X.6  
{ A_4.>g  
nStartPos += fileAccessI.write(b,0,nRead); n9%&HDl4  
//if(nThreadID == 1) {!L25  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yrF"`/zv6|  
} 6CV9ewr  
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Utility.log("Thread " + nThreadID + " is over!"); sQXj?5!  
bDownOver = true; @2`$ XWD  
//nPos = fileAccessI.write (b,0,nRead); ~Z>!SMXp<  
} -cONC9=  
catch(Exception e){e.printStackTrace ();} mm:g9j  
} 8#{DBWU  
} +V
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//打印回应的头信息 7C>5XyyJ  
public void logResponseHead(HttpURLConnection con) &cSZ?0R  
{ PC<[$~  
for(int i=1;;i++) VR XK/dZ  
{ ^2a63_  
String header=con.getHeaderFieldKey(i); X-<l+WP  
if(header!=null) =L]GQ=d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BW
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Utility.log(header+" : "+con.getHeaderField(header)); d=DQS>Nz  
else h0aK}`/a  
break; pGdFeEkB/  
} [vTk*#Cl4  
} };;k5z I%  
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public void splitterStop() f 0r?cZ  
{ G -V~
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bStop = true; z=6zc-$y 9  
} K"/3/`T  
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} X.GK5Phd  
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f;=<$Y>i  
/* "O/ 6SV  
**FileAccess.java
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*//文件访问(定位，写) (b8ZADI*  
package NetFox; }0}=-g&  
import java.io.*; V [Wo9Y\  
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public class FileAccessI implements Serializable{ )?{jD  
=`ECM7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E1D0un  
RandomAccessFile oSavedFile; <!q_C5>XJ  
long nPos; !LJ4 S  
$'n?V=4  
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public FileAccessI() throws IOException "i,ZG$S#E  
{ x c|1?AFj  
this("",0); ^#!\VGnL  
} %.WW-S3  
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public FileAccessI(String sName,long nPos) throws IOException ]Q#k"Je  
{ 5KTPlqm0qF  
oSavedFile = new RandomAccessFile(sName,"rw"); 8RT<?I^5  
this.nPos = nPos; Z~]G+(  
oSavedFile.seek(nPos); |RL\2j|  
} @RHG@{x{K  
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public synchronized int write(byte[] b,int nStart,int nLen) &Qmb?{S0  
{
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int n = -1; <
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try{ *|ef#-|D  
oSavedFile.write(b,nStart,nLen); bwI"V
&*  
n = nLen; X>%li$9J.  
} gwbV$[.X  
catch(IOException e) Xp9] 9H.  
{ =
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e.printStackTrace (); ~gaWZQXyu  
} 1\J9QZX0  
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return n; 1DlXsup&?#  
} &3Lh
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} = |E8z u%  
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/* `I8ep=VZ  
**SiteInfoBean.java k2(k0HFR  
*/ .Rt~d^D@  
package NetFox; UW1i%u k  
jOd+LXPJ  
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public class SiteInfoBean { 86>@.:d  
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private String sSiteURL; //Site's URL %K,cGgp^)  
private String sFilePath; //Saved File's Path P)Rq\1:  
private String sFileName; //Saved File's Name 2O- 4x  
private int nSplitter; //Count of Splited Downloading File -hq^';,  
N)PkE>%X  
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public SiteInfoBean() zK>m4+)~  
{//nSplitter的缺省值为5 %{rPA3Xoy  
//default value of nSplitter is 5 wp83E,  
this("","","",5); ky&wv+7  
}
^
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vz)R84  
{ 9GsG*$-I  
sSiteURL= sURL; 1CR\!?  
sFilePath = sPath; K4]#X"  
sFileName = sName; =[zP
 
this.nSplitter = nSpiltter; 2%pU'D:  
u8t|!pMF8  
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} oW(EV4J"  
#;5Qd'  
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public String getSSiteURL() "ZPgl 8  
{ HAo=t  
return sSiteURL; Jd?qvE>Pp  
} a5aHv/W#P  
 ?!<Q8=  
U#bmMH  
public void setSSiteURL(String value) `%^w-'  
{ &['L7  
sSiteURL = value; A
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}  NEPK  
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fUfd5W1"  
public String getSFilePath() ]Yf^O @<<>  
{ gK(G1  
return sFilePath; }p-/R'  
} t: oQHhO?  
8'_MCx(  
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public void setSFilePath(String value) +'+Nr<  
{ V#|/\-@  
sFilePath = value; Q2)(tB= )  
} /9,'.  
dh.{lvlX|  
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public String getSFileName() p~Cz6n  
{ mXS"nd30bD  
return sFileName; XA(.O|VZ  
} $CJf 0[|  
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public void setSFileName(String value) C9!FnvH
 
{ ,grx'to(X  
sFileName = value; $tI<MZ&Z  
} sDR Av%w  
]~VuY:abH  
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public int getNSplitter() S8+l!$7  
{ Z!Z{Gm3  
return nSplitter; DU)q]'[u  
} m#G,m  
<#;5)!gr{  
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public void setNSplitter(int nCount) #_`p 0wY  
{ 8a]g>g  
nSplitter = nCount; -q[x"Ha%  
} `sIm&.d  
} akPd#mf  
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/* I<,~>'cq.  
**Utility.java PC+Soh*  
*/ %Tu(>vnuj  
package NetFox; {O).!  
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public class Utility { z
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v _:KqdmO]  
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public Utility() (UhJ Pco"  
{ ]dl.~;3~~  
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} ^'du@XCf}  
>?)_, KL  
//线程睡眠 _Gt;=  
public static void sleep(int nSecond) [\ Sd*-  
{ {oF;ZM'r  
try{ ]q4LNo  
Thread.sleep(nSecond); R.l
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} d0|{/4IWw;  
catch(Exception e) 0-aaLC~Z>  
{ |+JO]J#bc  
e.printStackTrace (); N?#L{Yt  
} T][c^K*  
} OC-d5P  
^_V0irv  
//日志 -|s%5p|  
public static void log(String sMsg) q[W@.[2y)  
{ y!
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System.err.println(sMsg); \I/"W#\SJo  
} |; mET  
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xaB#GdD  
public static void log(int sMsg) fhRu-  
{ $G}k'[4C  
System.err.println(sMsg);  P s|[  
} H8B.c%_|U  
} 'qo(GGC M  
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K.&6c,P]  
/* |HJ`uGN<b  
**TestMethod.java Au/'|%2#(  
*/ bO6cv{>x  
package NetFox; WLh!L='{BK  
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QkTU@T6>o  
public class TestMethod { 9^C6ZgNS  
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X MF
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public TestMethod() 4\ )WMP  
{ ///xx/weblogic60b2_win.exe $:-C9N29  
try{ .{bT9S
c5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tBwPB#:W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N>P" $  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [Q6$$z92Q  
fileFetch.start(); BtJF1#f  
} Kuk@x.~0m  
catch(Exception e){e.printStackTrace ();} ~j!|(a7
  
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} &#~U1: 0  
:,/ \E  
|qf9-36  
public static void main(String[] args) 9NU-1vd~  
{ -A:'D8o#f  
new TestMethod(); ~+RrL,t#  
} Tn38]UL  
} s <$*A;t  
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