http断点续传简单实现（java)

/* 91H0mP>ki  
**SiteFileFetch.java $)Yog]}  
*/ a[n$qPm}  
package NetFox; `?JgHk  
import java.io.*; ~7pjk  
import java.net.*; kA__*b}8UK  
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vC:b?0s#(  
public class SiteFileFetch extends Thread { 4Umsc>yfK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean M"^Vf{X^  
long[] nStartPos; //开始位置 5vft}f  
long[] nEndPos; //结束位置 @@83PJFid  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _wNPA1q0J  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 gvNZrp>e!  
boolean bStop = false; //停止标志 -j_I_  
File tmpFile; //文件下载的临时信息 :(>9u.>l?5  
DataOutputStream output; //输出到文件的输出流 -l H>8+  
| ",[C3Jg  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >&QH{!(  
public SiteFileFetch(SiteInfoBean bean) throws IOException Rt^<xXX$  
{ {~fCqP.2  
siteInfoBean = bean; 4q13xX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *O>aqu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UglG!1L  
if(tmpFile.exists ()) A&c@8  
{ ]^9* t,{9  
bFirst = false; y?n2`l7f  
read_nPos();
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} ]"Y%M'  
else kQVDC,d  
{ ~9r!m5ws  
nStartPos = new long[bean.getNSplitter()]; QaWHz   
nEndPos = new long[bean.getNSplitter()]; $-Pqs ^g  
} >}b6
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} 6@q[tN7_^  
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public void run() Jh4&Qh|t  
{ 3;MjO*-  
//获得文件长度 0^_
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//分割文件 EB5_;  
//实例FileSplitterFetch Hpi%9SAM  
//启动FileSplitterFetch线程 ny(GTKoUz  
//等待子线程返回 eQFb$C]R}y  
try{ 7TkxvSL X  
if(bFirst) vM
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{ Y#&0x_Z  
nFileLength = getFileSize(); U`8|9v  
if(nFileLength == -1) G4Kmt98I  
{ D2</^]3Su  
System.err.println("File Length is not known!"); +Y)#yGUn  
} i*CQor6|z  
else if(nFileLength == -2) Tz[?gF.Do  
{ =6L*!JP<  
System.err.println("File is not access!"); eR-=<0Iw;  
} wD],{y  
else nS+FX&_  
{ #M?F^u[  
for(int i=0;i<nStartPos.length;i++) Ah>gC!F^  
{ o}
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sf&?3a+f  
} jD/7/G*  
for(int i=0;i<nEndPos.length-1;i++) XDkS ^9  
{ M6
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nEndPos = nStartPos[i+1]; 6W;?8Z_1  
} {(Og/
[  
nEndPos[nEndPos.length-1] = nFileLength; %,,`N I{  
} ;wXY3|@  
} 3XwU6M$5g  
^'&iYV  
=r@gJw:B  
//启动子线程 a1G9wC:e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *i?rJH  
for(int i=0;i<nStartPos.length;i++) |vfujzRZ  
{ +z|UpI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jefNiEE[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), - LiPHHX<  
nStartPos,nEndPos,i); LMFK3
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >H}jR[H'  
fileSplitterFetch.start(); Ty3CBR{6  
} SgpZ;\_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .6#cDrK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /z1p/RiX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `M?v!]o  
nEndPos = " + nFileLength); e)HhnN@  
// fileSplitterFetch[nPos.length-1].start(); m\/,cc@,  
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//等待子线程结束 1Sg|3T8bGT  
//int count = 0; f4'El2>-86  
//是否结束while循环 v`S2M  
boolean breakWhile = false; .QXG"R  
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while(!bStop) Rkpr8MS  
{ w dGpt_  
write_nPos(); \[hn]@@  
Utility.sleep(500); 9DOkQnnc  
breakWhile = true; -c+>j  
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for(int i=0;i<nStartPos.length;i++) V(;55ycr  
{  ofMu3$Q  
if(!fileSplitterFetch.bDownOver) W?qpnPW  
{ x0\e<x9s  
breakWhile = false; -uA3Y  
break; Z}8k[*.  
} ]By0Xifew  
} |*^8~u3J"  
if(breakWhile) `]`=]*d  
break; URYZV8=B~  
q.=^iz&m  
=oE_.ux\  
//count++; 5LQk8NPh  
//if(count>4) JFkN=YR8  
// siteStop(); WI1T?.Gc   
} :7p9t.R<$h  
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System.err.println("文件下载结束！"); bz{^h'  
} j)jCu ;`  
catch(Exception e){e.printStackTrace ();} <nDNiM#  
} +I|Rk&  
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//获得文件长度 o]Z _@VI  
public long getFileSize() Hf VHI1f  
{ z)4UMR#b&  
int nFileLength = -1; ;>NP.pnA
)  
try{ _*s~`jn{H  
URL url = new URL(siteInfoBean.getSSiteURL()); P+Wm9xR2d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zlH28V  
httpConnection.setRequestProperty("User-Agent","NetFox"); SQ}S4r  
5;W\2yj
 
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int responseCode=httpConnection.getResponseCode(); HSNOL  
if(responseCode>=400) m6b$Xyq[  
{ Ri|k<io  
processErrorCode(responseCode); M_k`%o  
return -2; //-2 represent access is error 8 AFMn[{  
} JC=dYP}  
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String sHeader; B@-|b  
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for(int i=1;;i++) Le*`r2  
{ 0|g[o:;fl_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WtIMvk  
//Utility.log(in.readLine()); }N?g|  
sHeader=httpConnection.getHeaderFieldKey(i); wHx}U M"  
if(sHeader!=null) :^n*V6.4  
{ YWEYHr;%^?  
if(sHeader.equals("Content-Length")) 6`acg'sk>  
{ o`idg[l.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (Aorx #z  
break; P{?;T5ap6  
} G'u|Q mb1  
} 'e F%  
else `M&P[.9Pz  
break; 5J  ySFG3  
} Ua %UbAt  
} .}o~VT:!?Y  
catch(IOException e){e.printStackTrace ();}  Nj+a2[  
catch(Exception e){e.printStackTrace ();} ;_}~%-_ ~  
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Utility.log(nFileLength); iC\%_5/_  
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return nFileLength; :vpl+)n  
} tZbFvk2  
6,X+1EXY  
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//保存下载信息（文件指针位置） V\0E=M*P  
private void write_nPos() GWhE8EDT  
{ ?=<~^Lk  
try{ JnY$fs*"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1B 5:s,Oyj  
output.writeInt(nStartPos.length); Xh?4mKgu  
for(int i=0;i<nStartPos.length;i++) vDsF-
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{ C8ZL*9U  
// output.writeLong(nPos); SAR= {/  
output.writeLong(fileSplitterFetch.nStartPos); C0QM#"[  
output.writeLong(fileSplitterFetch.nEndPos); oe9lF*$/  
} &:<, c12  
output.close(); "tUwo(K[  
} `{[RjM`  
catch(IOException e){e.printStackTrace ();} UbO4%YHt  
catch(Exception e){e.printStackTrace ();} h h"h j  
} vwmBUix  
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{=67XrWN1  
//读取保存的下载信息（文件指针位置） 8f|98T"  
private void read_nPos() j C)-`_  
{ 5MR,UgT  
try{ qw<HY$3=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /&r|ec5  
int nCount = input.readInt(); M*w'1fT  
nStartPos = new long[nCount]; h$`#YNd'  
nEndPos = new long[nCount]; <`)iA-Df;9  
for(int i=0;i<nStartPos.length;i++) \9`#]#1bx5  
{ 8#w)X/  
nStartPos = input.readLong(); ]W/>Ldv  
nEndPos = input.readLong(); 4jX3lq|  
} ~Wei|,w'<  
input.close(); 0mTr-`s  
} xR?V,uV'$&  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} %Ds+GM-  
} Ab2Q \+,  
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private void processErrorCode(int nErrorCode) BEUK}T K4  
{ >&Y-u%}U  
System.err.println("Error Code : " + nErrorCode); U<^F4*G  
} U\zD,<I9  
o:~LF6A-  
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//停止文件下载 j/KO|iNL2  
public void siteStop() po7>IQS]  
{ B$XwTJ>  
bStop = true; Ji?#.r`"n  
for(int i=0;i<nStartPos.length;i++) wMWW=$h#\  
fileSplitterFetch.splitterStop(); d|lpec  
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} A%XX5*  
} rS7)6h7(7  
//负责部分文件的抓取 v-Qmx-N  
**FileSplitterFetch.java wNY
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*/ X!>eiYK)  
package NetFox; w!&~??&=}  
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import java.io.*; l
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import java.net.*; BUsV|e\  
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public class FileSplitterFetch extends Thread { nB5zNyY4  
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String sURL; //File URL fuMJdAuY7d  
long nStartPos; //File Snippet Start Position Pw[g  
long nEndPos; //File Snippet End Position !)pdamdA  
int nThreadID; //Thread's ID O9"/ kmB  
boolean bDownOver = false; //Downing is over k~.&j"K  
boolean bStop = false; //Stop identical [{ ~TcT  
FileAccessI fileAccessI = null; //File Access interface t9cl"
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .iHn5SGA  
{ >V$ Gx>I  
this.sURL = sURL; ])}]/Qw  
this.nStartPos = nStart; Qk976  
this.nEndPos = nEnd; }H"kU2l  
nThreadID = id; eE@&ze>X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }4//@J?:  
} g(|{')8?d  
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public void run() #oni:]E!m  
{ 3W_PE+:Kr  
while(nStartPos < nEndPos && !bStop) jE\Sm2G9  
{ om h{0jA0  
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try{ ,yd=e}lQx  
URL url = new URL(sURL); _zWfI.o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T0zn,ej  
httpConnection.setRequestProperty("User-Agent","NetFox"); \S~Vx!9w  
String sProperty = "bytes="+nStartPos+"-"; F4L;BjnJ  
httpConnection.setRequestProperty("RANGE",sProperty); \Ae9\Jp8M  
Utility.log(sProperty); YXo|~p;=Y  
Z\}K{#   
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InputStream input = httpConnection.getInputStream(); Av'GB  
//logResponseHead(httpConnection); CQh,~  
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byte[] b = new byte[1024]; ^BQrbY  
int nRead; P [Uy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9ZXlR?GA  
{ uocHa5J  
nStartPos += fileAccessI.write(b,0,nRead); }a AH  
//if(nThreadID == 1) 6/V3.UP-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <FI-zca  
} ma'FRt  
!V2/A1?  
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Utility.log("Thread " + nThreadID + " is over!"); 6Htg5o|W  
bDownOver = true; F# T 07<  
//nPos = fileAccessI.write (b,0,nRead); 9d[5{"2j  
} D,qu-k[jMI  
catch(Exception e){e.printStackTrace ();} b` Hz$8  
} O3DmNq$dz  
} a2Pf/D]n  
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G)v #+4  
//打印回应的头信息 W6H,6v  
public void logResponseHead(HttpURLConnection con) 10!wqyj&  
{ ,<BbpIQ2o  
for(int i=1;;i++) *}k;L74|  
{ ^sN (
  
String header=con.getHeaderFieldKey(i); 8{`?=&%6  
if(header!=null) 1$qh`<\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,1OyN]
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Utility.log(header+" : "+con.getHeaderField(header)); b2b?hA'k  
else <Rh6r}f  
break; r}[7x]sP  
} Wjhvxk  
} &nBa
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public void splitterStop() _4^R9Bt  
{ l2N]a9bq@  
bStop = true; iY"l
}.7)  
} \%^%wXfp  
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} "BX!  
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P) 3mX.(}  
/* .`>y@p!  
**FileAccess.java [
q !TIq  
*//文件访问(定位，写) "HE^v_p  
package NetFox; \+aC"#+0  
import java.io.*; 5onm]V]  
2^i(gaXUQ  
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public class FileAccessI implements Serializable{ q.,JVGMS  
23~Sjr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Xy5e5K  
RandomAccessFile oSavedFile; 8Q_SRwN  
long nPos; R<OI1,..r  
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public FileAccessI() throws IOException J9~g|5  
{ {e|[%reSkg  
this("",0); Z+@2"%W  
} S)DnPjN{  
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public FileAccessI(String sName,long nPos) throws IOException Q-1vw6d  
{ r Tz$^a}/  
oSavedFile = new RandomAccessFile(sName,"rw"); OpHsob~  
this.nPos = nPos; yn#X;ja-  
oSavedFile.seek(nPos); 0jEL<TgC  
} =:~R=/ZXk  
~6p[El#tS  
&
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public synchronized int write(byte[] b,int nStart,int nLen) `]%|f  
{ /~3r;M  
int n = -1; rS;Dmm  
try{ yj\Nk
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oSavedFile.write(b,nStart,nLen); M3q|l7|9  
n = nLen; '3g[]M@M  
} ?!+MM&c-n  
catch(IOException e) DY`kx2e!  
{ <~WsD)=$  
e.printStackTrace (); =zz~kon9  
} S_Wrw z  
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return n; xoN3  
} 1u:< 25  
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}9FSO9*&}  
} ;XBI{CW  
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/* P(f0R8BE  
**SiteInfoBean.java 6}!#;@D~
 
*/ $6
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package NetFox; H*r)Z90  
N'GeHByIT  
()6wvu}  
public class SiteInfoBean { }F#okU  
!*7vFl  
VT\F]Oa#  
private String sSiteURL; //Site's URL N$U$5;r~`  
private String sFilePath; //Saved File's Path %yv<y+yP~  
private String sFileName; //Saved File's Name Tu).K.p:  
private int nSplitter; //Count of Splited Downloading File =ACVE;L?  
f}9zgWU  
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public SiteInfoBean() Gz,i~XX  
{//nSplitter的缺省值为5 '/^qJ7eb  
//default value of nSplitter is 5 sTn<#l6  
this("","","",5); KbA?7^zo`  
} NTYg[VTr  
n(;|q&3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I|^;B8[  
{ 7/I,HxXp!  
sSiteURL= sURL; HTX?,C_  
sFilePath = sPath; 9_Be0xgJ3^  
sFileName = sName; tMf}   
this.nSplitter = nSpiltter; H9YW  
A#EDkU,  
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} x!5'`A!W%  
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8%A#`)fb  
public String getSSiteURL() `d5%.N  
{ l]Ax:Z  
return sSiteURL; +BETF;0D  
} TO]@ Zu1  
_m5uDF?[  
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public void setSSiteURL(String value)  zv0l,-o  
{ 2$+bJJM  
sSiteURL = value; itBwCIjG  
} D$ dfNiCH  
6jE|  
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public String getSFilePath() MQ5R O;RY  
{ ;oW6 NJ  
return sFilePath; e7Xeo+/  
} Dfg2`l  
[uC]*G]  
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public void setSFilePath(String value) 3!XjtVhK?I  
{ *W,]>v0%T  
sFilePath = value; ?Y-%'J(  
} ($au
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public String getSFileName() 5na~@-9p  
{ Q sZx) bO  
return sFileName; 0^I|ut4  
} JjPKR?[>  
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public void setSFileName(String value) Tl(^  
{ IHam4$~-  
sFileName = value; ;X?}x%$  
} nKPYOY8^  
0 HGM4[)=  
7X0Lq}G@  
public int getNSplitter() Sg&UagBj  
{ !\nBh  
return nSplitter; z:8eEq3w  
} FQu8vwV6>  
V
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public void setNSplitter(int nCount) zL$@`Eh-KP  
{ sD{Wxv  
nSplitter = nCount; e<3K;Q  
} *W.C7=  
} [B+yyBtx  
QQ%D8$k"  
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/* o<|cA5f\  
**Utility.java E(O74/2c8  
*/ ykl .1(  
package NetFox; .z]Wyx&/U  
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%-)H^i~]%  
public class Utility { AJh w  
&~8oQC-eF  
+AR5W(&  
public Utility() AP68V  
{ #*QO3y~ZM  
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.:@Ykdm4I  
} C`$n[kCJ  
!k6K?xt  
//线程睡眠 dYT%  
public static void sleep(int nSecond) ^Y=\#-Dd  
{ "3Uv]F  
try{ GC>e26\:  
Thread.sleep(nSecond); tX5"UQA  
} d6'{rje(  
catch(Exception e) ~<O7$~  
{ OBMTgZHxv  
e.printStackTrace (); 0rOfrTNOz%  
} rX4j*u2u  
} RX
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//日志 ~ DBcIy?  
public static void log(String sMsg) 419x+3>}  
{ Q3 u8bx|E  
System.err.println(sMsg); T^Y([23  
} 
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=8t]\Y?  
!B\R''J5  
public static void log(int sMsg) W{5#@_pL  
{ lhYe;b(  
System.err.println(sMsg); {{B%f.  
} !zkZQ2{Wn  
} '_GrD>P)-  
qCljo5Tq'  
Yn@lr6s  
/* 6%t1bM a  
**TestMethod.java byLft1  
*/ E;Y;z  
package NetFox; M@`;JjtSA  
&^#VN%{  
-&3hEv5  
public class TestMethod { =-8bsV/l  
P+s!|7'  
X'd9[).  
public TestMethod() i>D.!x  
{ ///xx/weblogic60b2_win.exe U&Wt%U{  
try{ t; 4]cg:_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _I)U%?V+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =h0,?]z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Jth[DUH8H  
fileFetch.start(); y0#u9t"Z;  
} E7.2T^o;M  
catch(Exception e){e.printStackTrace ();} !ePr5On  
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} 9fhsIe  
VHCK2}ps  
4kBaB  
public static void main(String[] args) *~t6(
v?  
{ vRs,zL$W  
new TestMethod(); K('hC)1  
} g;2?F[8Th  
} ~$)2s7 O  
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