http断点续传简单实现（java)

/* %fv)7 CRM  
**SiteFileFetch.java >!}`%pk(  
*/ ,d|vP)SS  
package NetFox; %,|ztH/ Q  
import java.io.*; t^.'>RwW|  
import java.net.*; )Pli})  
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public class SiteFileFetch extends Thread { 5
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SiteInfoBean siteInfoBean = null; //文件信息Bean Sj)}qM-y#  
long[] nStartPos; //开始位置 [Uli>/%JB  
long[] nEndPos; //结束位置 TFy7HX
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 fYBH
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long nFileLength; //文件长度 YUscz!rM  
boolean bFirst = true; //是否第一次取文件 2zK"*7b?  
boolean bStop = false; //停止标志 55-D\n<  
File tmpFile; //文件下载的临时信息 9cQ_mgch  
DataOutputStream output; //输出到文件的输出流 G;TsMq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） : ,p||_G&  
public SiteFileFetch(SiteInfoBean bean) throws IOException bC~~5Cm  
{ Fc8E Y*  
siteInfoBean = bean; JDv-O&]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B,_`btJ
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ''S&e  
if(tmpFile.exists ())   \&a.}t  
{ . uR M{Bs  
bFirst = false; <tbZj=*O/o  
read_nPos(); i"HgvBHx  
} 9cd8=][  
else aV>aiR=  
{ .0|
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nStartPos = new long[bean.getNSplitter()]; RH(V^09[o  
nEndPos = new long[bean.getNSplitter()]; [;KmT{I9  
} st/n"HQ  
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} vG Vd  
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public void run() >fzwFNdo  
{ sG,+  
//获得文件长度 Y)XvlfJ,h?  
//分割文件 >t3'_cBC!  
//实例FileSplitterFetch _8><| 3d  
//启动FileSplitterFetch线程 )NT5yF,m  
//等待子线程返回 n.hElgkUOr  
try{ W#XG;  
if(bFirst) \M(*=5  
{ u@=?#a$$  
nFileLength = getFileSize(); 9vI]LfP  
if(nFileLength == -1) ^bUxLa[.  
{ *Oo &}oAj  
System.err.println("File Length is not known!"); }nud  
} NQ9Ojj{#  
else if(nFileLength == -2) GK{{7B  
{ RY=1H  
System.err.println("File is not access!"); Pxhz@":[  
} z^W$%G  
else }+RB=#~o  
{ 6)e5zKW!?  
for(int i=0;i<nStartPos.length;i++) wAYB RY[  
{ C+%K6/J(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lIf(6nm@  
} zgKY4R{V  
for(int i=0;i<nEndPos.length-1;i++) R$m`Z+/@  
{ iOqk*EL_r\  
nEndPos = nStartPos[i+1]; I^3:YVR&  
} $h28(K%  
nEndPos[nEndPos.length-1] = nFileLength;  "0&N}  
} G'x 
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} E\{<;S  
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//启动子线程 H4<Nnd\   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C!%:o/  
for(int i=0;i<nStartPos.length;i++) h`5)2n+P  
{ XU-m"_t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K:r\{#9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8`v$liH  
nStartPos,nEndPos,i); H?yE3w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q:Mh
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fileSplitterFetch.start(); i0pU!`0  
} *'ZN:5%H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jx|I6y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); HIf{Z* mb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^O6*e]C$  
nEndPos = " + nFileLength); [-w@.^:]X  
// fileSplitterFetch[nPos.length-1].start(); RT*5d;l0  
>V;,#5F_  
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//等待子线程结束 {CUk1+  
//int count = 0; .T.5TMiOSq  
//是否结束while循环 Xl%0/o  
boolean breakWhile = false; 9E1W|KE  
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while(!bStop) Qv#]81i(1  
{ eN-au/kN  
write_nPos(); E9 Y\X  
Utility.sleep(500); HJhH-\{@  
breakWhile = true; S>_27r{  
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for(int i=0;i<nStartPos.length;i++) :q+N&j'3  
{ $=aI"(3&  
if(!fileSplitterFetch.bDownOver) (P@Y36j>N  
{ or?%-)  
breakWhile = false; 85]SC$  
break; ;IZ
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} p25Fn`
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} 3/goCg  
if(breakWhile) >3D7tK(  
break; ?m"|QS!!K  
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//count++; &M"ouy Zo9  
//if(count>4) py<_HyJ  
// siteStop(); "="O >  
} n:#TOU1ix<  
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System.err.println("文件下载结束！"); P-Su5F  
} %3=J*wj>D  
catch(Exception e){e.printStackTrace ();} NHaMo*xQ  
} K"{HseN{  
(> "QVxr  
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//获得文件长度 ZX.TqvK/r  
public long getFileSize() {aj/HFLNY  
{ %c/^_.  
int nFileLength = -1; Un@\kAY  
try{ "{BqtU*.  
URL url = new URL(siteInfoBean.getSSiteURL()); xJ(:m<z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pyB~M9Bp/  
httpConnection.setRequestProperty("User-Agent","NetFox"); SGcBmjP  
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int responseCode=httpConnection.getResponseCode(); ;;&F1@3tBa  
if(responseCode>=400) y?z\L
 
{ l";'6;g  
processErrorCode(responseCode); L-h$Z
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return -2; //-2 represent access is error  <!'M} s  
} x:z0EYL  
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String sHeader; HFtf  
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for(int i=1;;i++) *^XbDg9  
{ -|_ir-j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DJ;g|b  
//Utility.log(in.readLine()); pR$6,Vi  
sHeader=httpConnection.getHeaderFieldKey(i); "S!3m9_#  
if(sHeader!=null) <Gb %uny  
{ }GZbo kWg.  
if(sHeader.equals("Content-Length")) #MgvG,  
{ kDsIp=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Tj`5L6N;8  
break; ;+_8&wbqW  
} JdNF-64ky  
} bI ITPxz  
else _ Jc2&(;  
break; <n0{7#PDqw  
} ;5S}~+j  
} \C|cp|A*&  
catch(IOException e){e.printStackTrace ();} lpC @I^:  
catch(Exception e){e.printStackTrace ();} +1`t}hO  
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Utility.log(nFileLength); #G;X' BN  
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return nFileLength; n9UKcN-  
} < K%j  
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//保存下载信息（文件指针位置） <@#PF$!  
private void write_nPos() 2C "=!'  
{ b-<HXn_Fd  
try{ l(kr'x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }C#3O{5  
output.writeInt(nStartPos.length); oyeG$mpg  
for(int i=0;i<nStartPos.length;i++) 8tc*.H{^+  
{ %'ZN`XftG  
// output.writeLong(nPos); < oI8-f  
output.writeLong(fileSplitterFetch.nStartPos); ;A#~`P  
output.writeLong(fileSplitterFetch.nEndPos); :)c80`-E  
} Ot9V< D6h  
output.close(); f(:1yl\a  
} 3N4.$#>#9@  
catch(IOException e){e.printStackTrace ();} Y E1Hpeb  
catch(Exception e){e.printStackTrace ();} 9){  
} 3Sh+u>w  
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//读取保存的下载信息（文件指针位置） l5O=V
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private void read_nPos() o/p-!  
{ FC>d_=V  
try{ #gv4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +;gsRhWk  
int nCount = input.readInt(); ?pwE
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nStartPos = new long[nCount]; @.$MzPQQI  
nEndPos = new long[nCount]; );JJ2Jlkd  
for(int i=0;i<nStartPos.length;i++) TSto9$}*  
{ .[j%sGdKl  
nStartPos = input.readLong(); Mq\~`8V  
nEndPos = input.readLong(); []p"3i  
} r6Nm!Bq7  
input.close(); 5Pke8K  
} 32>x^>G=>  
catch(IOException e){e.printStackTrace ();} XAD3Z?  
catch(Exception e){e.printStackTrace ();} la, h  
} 9([6d.`~  
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private void processErrorCode(int nErrorCode) %e=!nRc  
{ T\sNtdF`:  
System.err.println("Error Code : " + nErrorCode); t4K56H.L?  
} C0m\SNR  
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\ TL82H@D  
//停止文件下载 .Ff_s  
public void siteStop() 1f//wk|  
{ ->oz#   
bStop = true; m,6he
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for(int i=0;i<nStartPos.length;i++) e}"wL g]  
fileSplitterFetch.splitterStop(); tOg=zXm  
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} .6T4z7I  
} 8pe0$r`b  
//负责部分文件的抓取 uxDLDA$;  
**FileSplitterFetch.java a$}6:E  
*/ "tR}j,=S:D  
package NetFox; 9k>uRV6  
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import java.io.*; F`&>NQb  
import java.net.*; J(9=T<%T  
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public class FileSplitterFetch extends Thread { {ymb\$f  
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String sURL; //File URL U[fSQ`&D  
long nStartPos; //File Snippet Start Position O),
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long nEndPos; //File Snippet End Position _*`q(dYcf  
int nThreadID; //Thread's ID >q9{  
boolean bDownOver = false; //Downing is over W_J
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boolean bStop = false; //Stop identical z,+m[x=/N  
FileAccessI fileAccessI = null; //File Access interface r)
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8=4^Lm  
{ fM:80bnL+  
this.sURL = sURL; 2OCdG  
this.nStartPos = nStart; ^5x4q  
this.nEndPos = nEnd; n\>.T[$"  
nThreadID = id; 2"M
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 .^H1\p];Lw  
} 0/Q5d,'Y[2  
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public void run() [V5-%w^  
{ Z;J`5=TS  
while(nStartPos < nEndPos && !bStop) /v$]X4 S`  
{ 9 z*(8d  
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try{ L>:FGNf^H  
URL url = new URL(sURL); jt%WPkY:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "1%*'B^}bw  
httpConnection.setRequestProperty("User-Agent","NetFox"); U_Y;fSl>  
String sProperty = "bytes="+nStartPos+"-"; n/-N;'2J  
httpConnection.setRequestProperty("RANGE",sProperty); {6tx,;r(F  
Utility.log(sProperty); W-XN4:,qI  
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InputStream input = httpConnection.getInputStream(); V"g~q?@F  
//logResponseHead(httpConnection); R
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byte[] b = new byte[1024]; rgn|24x  
int nRead; {~1M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?,V;f2c  
{ Z@nmjji  
nStartPos += fileAccessI.write(b,0,nRead); n}5x-SxS0  
//if(nThreadID == 1) buc*rtHfA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |wJ),h8/  
} 6#-Z@fz%  
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Utility.log("Thread " + nThreadID + " is over!"); U]mO7HK  
bDownOver = true; ,s8&#1rJ-  
//nPos = fileAccessI.write (b,0,nRead); :|fl?{E  
} ~,+[M-  
catch(Exception e){e.printStackTrace ();} QvNi8TB  
} 1Kc{#+a^  
} q8tug=c  
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//打印回应的头信息 T-!|l7V~f  
public void logResponseHead(HttpURLConnection con) pfNThMf  
{ 1W7 iip,  
for(int i=1;;i++) Qv=Bq{N  
{ ?e2Y`0  
String header=con.getHeaderFieldKey(i); 7t+]z)  
if(header!=null) lDH_ Y]bM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /gF]s_
 
Utility.log(header+" : "+con.getHeaderField(header)); BDnBBbBrz  
else EyPy*_A  
break; 5?)}F/x  
} -KA4Inn]5  
} fl!1AKSn@N  
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public void splitterStop() 0=gF6U  
{
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bStop = true; m(h/:JZ\  
} B=^2g}mgK  
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} uvNnW}G4  
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W *|OOa'  
/* Mof)2Hbd:  
**FileAccess.java 9EjjkJ%)q  
*//文件访问(定位，写) ^M"HSewo  
package NetFox; b^;N>zx  
import java.io.*; }v,W-gA  

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public class FileAccessI implements Serializable{ $o
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Sk!v,gx  
RandomAccessFile oSavedFile; =/M$ <+  
long nPos; z
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public FileAccessI() throws IOException  |UABar b  
{ i:AjWC@]  
this("",0); ~4}*D
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} ?%_]rr9  
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public FileAccessI(String sName,long nPos) throws IOException wV]sGHuF}  
{ s=3EBh  
oSavedFile = new RandomAccessFile(sName,"rw"); alWx=+d  
this.nPos = nPos; \E>%W  
oSavedFile.seek(nPos); Fwg#d[:u  
} vK[v eFH  
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public synchronized int write(byte[] b,int nStart,int nLen) a-SB1-5jf  
{ {^2({A#&  
int n = -1; 4UkP:Vz:  
try{ ?Aj\1y4L1  
oSavedFile.write(b,nStart,nLen); ]JGKL5~p  
n = nLen; IiYuUN1D  
} j&o/X7I=  
catch(IOException e) =<Zwv\U  
{ >MBn2(\B;  
e.printStackTrace ();
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} 7H/!rx  
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return n; !W(/Y9g#  
} "E4i >g  
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} l{B<"+8  
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/* /zDSlj<c  
**SiteInfoBean.java YA1{-7'Q  
*/ ]JhDRJ\  
package NetFox; 7%~VOB  
Bh.6:9{  
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public class SiteInfoBean { 64IeCAMVo  
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private String sSiteURL; //Site's URL #8WR{  
private String sFilePath; //Saved File's Path a78;\{&L'  
private String sFileName; //Saved File's Name &@
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private int nSplitter; //Count of Splited Downloading File 3P=Eb!qtdD  
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public SiteInfoBean() qHcY 2LV  
{//nSplitter的缺省值为5 q?gQ  
//default value of nSplitter is 5 *NX*/(Q  
this("","","",5); *$*nY [/5  
} iq[2H$  
o} bj!h]N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q=j/s4~  
{ SWe!9Y$  
sSiteURL= sURL; 7,&3=R<
 
sFilePath = sPath; z}Mb4{d1  
sFileName = sName; ocDVCCkxg  
this.nSplitter = nSpiltter; !X#3
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} %te'J G<  
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public String getSSiteURL() 7J)Hwl  
{ %\s#e  
return sSiteURL; tjc5>T[Es8  
} k(w9vt0?  
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public void setSSiteURL(String value) ?><   
{ $`+~QR!h  
sSiteURL = value; F".IB^}$  
} joSr,'x  
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public String getSFilePath() IhFw{=2*  
{ NnSI)*%'  
return sFilePath; "S:NU.
c?  
} *+1"S ]YF  
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public void setSFilePath(String value) t]YLt ,  
{ XDv7#Tv_wv  
sFilePath = value; C[/
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} =kZwB*7  
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public String getSFileName() tMs|UC  
{  +T8XX@#  
return sFileName; #Z3I%bkw H  
} IWbp^l+!t  
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public void setSFileName(String value) c)P%O  
{ SBB bniK-  
sFileName = value; 2l}FgD  
} 4s+J-l  
?28G6T]/?d  
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public int getNSplitter() ^9m]KEucd7  
{ Ee?K|_\${  
return nSplitter; 'E6gEJ  
} xhoLQD  
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public void setNSplitter(int nCount) 5)
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{ '| Q*~Lh  
nSplitter = nCount; 5a/ A_..+I  
} AFF>r#e  
} }5c'ui!3H  
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/* VL,?91qwe  
**Utility.java nr9#3Lb  
*/ ObHz+qRG  
package NetFox; = ,E(!Sp  
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public class Utility { zdQu%q  
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public Utility() l8 2uK"M  
{ /3:IE%o  
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} Y_iF$m/R  
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//线程睡眠 fw~%^*  
public static void sleep(int nSecond) |$*9j""u  
{ 6"c!tJc7j  
try{ ^eT>R,aB  
Thread.sleep(nSecond); ,Z\,IRn  
} 4lo}-@j  
catch(Exception e) -,CndRKx  
{ {]^%?]e  
e.printStackTrace (); v lnUN  
} $;j6*,H  
} ,i((;/O6  
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//日志 ng)yCa_Ny  
public static void log(String sMsg) [g 68O*  
{ K#pt8Q  
System.err.println(sMsg); %!/liS  
} $TW+LWb   
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public static void log(int sMsg) b(rBha|  
{ *g
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System.err.println(sMsg); j`-y"6)  
} |^9ig_k`  
} !urd $Ta  
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/* tf}Q%)`f  
**TestMethod.java :zy'hu;  
*/ thboHPml{  
package NetFox; ~w}[ ._'#M  
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public class TestMethod { `pS)qx.a  
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public TestMethod() z_0lMX`  
{ ///xx/weblogic60b2_win.exe T%#P??k  
try{ V<I${i$]0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L|Gk}n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;,hoX6D$
 
SiteFileFetch fileFetch = new SiteFileFetch(bean); tg`!svL!  
fileFetch.start(); 2Mi;}J1C{  
} z:,!yU c  
catch(Exception e){e.printStackTrace ();} ><[.  
r
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} |(8h:g  
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public static void main(String[] args) w)>z3Lm  
{ ?)<XuMh  
new TestMethod(); b4OR`dd*J  
} 31\^9w__8  
} gMMd=  
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