http断点续传简单实现（java)

/* B<)c{kj  
**SiteFileFetch.java /58]{MfrJ  
*/ GJlkEWs  
package NetFox; k&Z3v.  
import java.io.*; o)w8 ]H/  
import java.net.*; `LD#fg*  
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public class SiteFileFetch extends Thread { SCbN(OBN!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean LR:Qb]|"  
long[] nStartPos; //开始位置  XL@Y!  
long[] nEndPos; //结束位置 f"^G\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?_
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long nFileLength; //文件长度 _Ju@<V$  
boolean bFirst = true; //是否第一次取文件 Vs>/q
:I  
boolean bStop = false; //停止标志 ]-  
File tmpFile; //文件下载的临时信息 5p9zl=mT  
DataOutputStream output; //输出到文件的输出流 hD OEJ  
{/f\lS.5g  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q)"L8v v  
public SiteFileFetch(SiteInfoBean bean) throws IOException B o@B9/ABv  
{ "BN-Jvb7q  
siteInfoBean = bean; ?QzA;8H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4[@`j{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); " oWiQ{\IP  
if(tmpFile.exists ()) 6.]x@=Wm  
{ k_A.aYe  
bFirst = false; yc|j]?  
read_nPos(); OKDBzl  
} l}|KkW\y  
else gHU/yi!T  
{ 3Q-i%7l  
nStartPos = new long[bean.getNSplitter()]; B?}ZAw>  
nEndPos = new long[bean.getNSplitter()]; vIk;x
  
} .gmNE$d  
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} C^uH]WO  
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public void run() fX)C8J^=G  
{ XwlAW7lU=  
//获得文件长度 }Qj
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//分割文件 {fsU(Jj\  
//实例FileSplitterFetch IvLo&6swW  
//启动FileSplitterFetch线程 .]_Ye.}  
//等待子线程返回 igNZe."V  
try{ -7_`6U2"  
if(bFirst) Aj`zT
'  
{ _sU|<1  
nFileLength = getFileSize(); } $:uN  
if(nFileLength == -1) FU-YI"  
{ a}
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System.err.println("File Length is not known!"); ]lj,GD)c  
} JX_hLy@`  
else if(nFileLength == -2) =*Z=My}3~  
{ S"FIQ&n  
System.err.println("File is not access!"); B7"/K]dR:  
} L%,tc~)A  
else Y)@mL~){  
{ :[#g_*G@p  
for(int i=0;i<nStartPos.length;i++) +dWx?$n  
{ VV/6~jy0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0i}4T:J@`  
} 4_3O?IY  
for(int i=0;i<nEndPos.length-1;i++) vJ*IUy  
{ R["2kEF  
nEndPos = nStartPos[i+1]; (17%/80-J  
} 2mS3gk  
nEndPos[nEndPos.length-1] = nFileLength; +hdD*}qauC  
} -^=sxi,V  
} Kg0Vbzvb  
Kp") %p#  
[uxhdR`T  
//启动子线程 4^1B'>I  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *@'4 A :A  
for(int i=0;i<nStartPos.length;i++) O!+LM{> F  
{ YDBQ6X  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T:+%3+;a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nenYP0  
nStartPos,nEndPos,i); y=y=W5#;77  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ui6f>0?  
fileSplitterFetch.start(); M/GQQG;  
} Sfc0 ~1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0raVC=[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '| Enc"U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ND[u$N+5x"  
nEndPos = " + nFileLength); '0g1v7Gx  
// fileSplitterFetch[nPos.length-1].start(); loVUB'OSv  
K @3 yS8F  
Y%9S4be  
//等待子线程结束 -|^}~yOx0=  
//int count = 0; a~YFJAkg9  
//是否结束while循环 ,)mqd2)+"  
boolean breakWhile = false; R }M'D15  
X%"
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while(!bStop) *OU>s;"$  
{ 0wZ_;FN*-  
write_nPos(); hNB;29r~  
Utility.sleep(500); i:`ur  
breakWhile = true; <{@?c  
?(GMe>  
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for(int i=0;i<nStartPos.length;i++) iMRb` \KH  
{ 03?TT,y$  
if(!fileSplitterFetch.bDownOver) pq[RH-{  
{ R?Y#>K  
breakWhile = false; 
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break; \KfngYD]W  
} U#G[#sd> K  
} V-a/%
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if(breakWhile) D+{h@^C9Z  
break; ~[XDK`B
  
xkR--/f  
cSCO7L2E18  
//count++; DZ~w8v7V  
//if(count>4) }h<\qvCcU  
// siteStop(); "UVqkw,vt  
} "!<Kmh5  
";B.^pBv@;  
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System.err.println("文件下载结束！"); 3F2> &p|7  
} kXS_:f;M  
catch(Exception e){e.printStackTrace ();} flTK  
} PETrMu<  
kRNr`yfN  
&,+G}  
//获得文件长度 #(3w6l2  
public long getFileSize() zsA6(?)u  
{ jPYed@[+  
int nFileLength = -1; V1Dwh@iS  
try{ >FPE%X0+  
URL url = new URL(siteInfoBean.getSSiteURL()); !q~s-~d^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x|*v(,7b]!  
httpConnection.setRequestProperty("User-Agent","NetFox"); G T#hqt'1x  
pI7\]e  
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int responseCode=httpConnection.getResponseCode(); aWek<Y~+  
if(responseCode>=400) b!SGQv(^M  
{ N( E\  
processErrorCode(responseCode); WwbExn<  
return -2; //-2 represent access is error wl^bvHG  
} t,= ta{ a  
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String sHeader; 4q[C' J  
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1  
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for(int i=1;;i++) DbJ:KQ!*  
{ &0SGAJlec  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %1SA!1>j  
//Utility.log(in.readLine()); G40,KCa  
sHeader=httpConnection.getHeaderFieldKey(i); <`5>;Xn=  
if(sHeader!=null) zkn K2e,$  
{ 2<>n8K  
if(sHeader.equals("Content-Length")) & S_gNa  
{ 1;3oGuHj8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); PXm{GLXRS;  
break; ]B=B@UO@.  
} ^DXERt&3  
} %!%3jo0t
 
else </tiNc  
break; QE84l  
} Dk|
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} 85$MHod}[,  
catch(IOException e){e.printStackTrace ();} \c/jp5=}  
catch(Exception e){e.printStackTrace ();} i0{pm q  
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xr?=gY3E;  
Utility.log(nFileLength); ['R2$z  
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return nFileLength; 2/=CrK  
} hD{+V!{  
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I!9u](\0  
//保存下载信息（文件指针位置） W*;~(hDz  
private void write_nPos() $EW31R5h<s  
{ 3ag*dBbs  
try{ v3[Z]+ ]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QW6F24  
output.writeInt(nStartPos.length); g[*+R9'  
for(int i=0;i<nStartPos.length;i++) VF!?B>  
{ %\\l/{`eW  
// output.writeLong(nPos); dMw7Lp&  
output.writeLong(fileSplitterFetch.nStartPos); ] M"{=z  
output.writeLong(fileSplitterFetch.nEndPos); zCL/^^#  
} Namw[TgJ  
output.close(); k6ERGQ9|I  
} X/lLM`  
catch(IOException e){e.printStackTrace ();} .
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catch(Exception e){e.printStackTrace ();} K6@QZc5.!  
} );}k@w fw)  
\MsAdYR  
+ htTrHjt  
//读取保存的下载信息（文件指针位置） gZ   
private void read_nPos() /tc*jXB  
{ TU$/3fp*  
try{ "^ydoRZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ( Z\OqG  
int nCount = input.readInt(); n*CH,fih:  
nStartPos = new long[nCount]; !e&ZhtTuC  
nEndPos = new long[nCount]; &fdH HN  
for(int i=0;i<nStartPos.length;i++) 4} 'Xrg  
{ W)1)zOD  
nStartPos = input.readLong(); (WR&Vt4Rh  
nEndPos = input.readLong(); djS?$WBpU  
} I.Co8is  
input.close(); /'QNlP[L;  
} *;Dd:D9  
catch(IOException e){e.printStackTrace ();} )W:`Q&/G  
catch(Exception e){e.printStackTrace ();} ,]i ^/fT  
} '$ ~.x|  
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private void processErrorCode(int nErrorCode) <wFR%Y/j  
{ ElZ'/l*\  
System.err.println("Error Code : " + nErrorCode); Op,Ce4A  
} R/waWz\D  
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//停止文件下载 _J}ce  
public void siteStop() -?!|W-}@G=  
{ iH#~eg  
bStop = true; ^uW](2  
for(int i=0;i<nStartPos.length;i++) Z=sy~6m+v  
fileSplitterFetch.splitterStop(); 7fLLV2  
miCt)Qd  
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} Nb>|9nu O  
} T3[\;ib}  
//负责部分文件的抓取 )pjd*+V  
**FileSplitterFetch.java fa=#S  
*/ Mlb=,l  
package NetFox; &0K;Vr~D  
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import java.io.*; r42[pi]F  
import java.net.*; ?1xBhKq  
! W$u~z  
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public class FileSplitterFetch extends Thread { SIKy8?Fn  
)F0_V 4  
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String sURL; //File URL X"(!\{ySI;  
long nStartPos; //File Snippet Start Position $|C%G6!s?@  
long nEndPos; //File Snippet End Position aa_&WHXkt  
int nThreadID; //Thread's ID Q nDymVF  
boolean bDownOver = false; //Downing is over ZFOYYht  
boolean bStop = false; //Stop identical ]}<.Y[!S  
FileAccessI fileAccessI = null; //File Access interface &vj+3<2  
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9BR  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xp7,0'(;  
{ S6$S%$  
this.sURL = sURL; ":"QsS#*"#  
this.nStartPos = nStart; m`g%\o^6i  
this.nEndPos = nEnd; nUQcoSY#  
nThreadID = id; X9/V;!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?Gp~i]  
} V3$!`T}g4  
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public void run() m1gJ"k6 `j  
{ ci+Pg9sS  
while(nStartPos < nEndPos && !bStop) MKJ9PcVi  
{ doFp53NhV  
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try{ en=Z[ZIPO  
URL url = new URL(sURL); BgA\l+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BtBo%t&  
httpConnection.setRequestProperty("User-Agent","NetFox"); .Ap[C? mV  
String sProperty = "bytes="+nStartPos+"-"; L(PJ9wjkD  
httpConnection.setRequestProperty("RANGE",sProperty); *na7/ysT<  
Utility.log(sProperty); $sU?VA'h  
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InputStream input = httpConnection.getInputStream(); !#rZeDmw  
//logResponseHead(httpConnection); <.l5>mgkCw  
)P[B!  
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byte[] b = new byte[1024]; |E53 [:p  
int nRead; 8hQ"rrj+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L FHyiIO  
{ [dk|lkj@u\  
nStartPos += fileAccessI.write(b,0,nRead); -gu)d5b  
//if(nThreadID == 1) '&?47+W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,T|iA/c
 
} nkS6A}i3o  
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Utility.log("Thread " + nThreadID + " is over!"); x)BG%{h  
bDownOver = true; -3wg9uZ&  
//nPos = fileAccessI.write (b,0,nRead); T(a*d7  
} qI<*Cze  
catch(Exception e){e.printStackTrace ();} 5iG|C ~  
} 2YuaPq/  
} S&_ZQLiQ$  
? @h  
5Lum$C c}  
//打印回应的头信息 XwX1i!'54  
public void logResponseHead(HttpURLConnection con) Kl(}s{YFn.  
{ 8}xU]N#EV  
for(int i=1;;i++) {4}Sl^kn*  
{ |g8 ]WFc  
String header=con.getHeaderFieldKey(i); .a;-7|x  
if(header!=null) {EW}Wd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fN0D\Mu!)b  
Utility.log(header+" : "+con.getHeaderField(header)); #xYkG5`lm  
else qbqJ1^!6R  
break; lDMYDy{<  
} eFsku8$<  
} <u4GIi <sm  
/I[cj3}{+f  
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public void splitterStop() tHJ1MDw'  
{ rp=?4^(u  
bStop = true; #n2GW^x  
} :JW~$4  
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} >f`}CLsY  
eHqf3f   
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/* "_?^uymw  
**FileAccess.java 3vrQY9H>  
*//文件访问(定位，写) S1$\D!|1  
package NetFox; Hsp|<;Yg  
import java.io.*; Sn0?_vH4  
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public class FileAccessI implements Serializable{ Ir0er~f+z  
_fMooI)U1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^.-P]I]  
RandomAccessFile oSavedFile; l#Qf8*0  
long nPos; AiO,zjM=  
_10#rucr  
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public FileAccessI() throws IOException !knYD}Rxd  
{ ?d_<S0j-)  
this("",0); *&5G+d2
 
} L G=Q  
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o  
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public FileAccessI(String sName,long nPos) throws IOException 
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{ iqOd]H]v  
oSavedFile = new RandomAccessFile(sName,"rw"); CdEJ/G:  
this.nPos = nPos; 'i`;Frmg  
oSavedFile.seek(nPos); @``!P&h  
} !).D  
DtZkrj)D/  
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public synchronized int write(byte[] b,int nStart,int nLen) X7n~Ws&s@  
{ z6Mf>q  
int n = -1; qbT].,?!U  
try{ VBd.5YW  
oSavedFile.write(b,nStart,nLen); &}P62&  
n = nLen; nR ,j1IUF  
} xQ$*K]VP  
catch(IOException e) x$A5Ved  
{ Llg[YBJ7>  
e.printStackTrace (); W=G[hT5L{  
} nQ/El&{  
.|o7YTcR
:  
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return n; y~W6DL}  
} A\ LTAp(I  
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} }l_) d  
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))k^7g9M`  
/* B)Gm"bLCOZ  
**SiteInfoBean.java kOkgsQQ  
*/ 1Z*-@%RX  
package NetFox; WE
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o&X!75^G>  
{)-%u8J\`N  
public class SiteInfoBean { `Y$LXF~,Om  
!d"J,.)  
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private String sSiteURL; //Site's URL E8)C_[QJ`  
private String sFilePath; //Saved File's Path pU}>}  
private String sFileName; //Saved File's Name >.zk-`>-  
private int nSplitter; //Count of Splited Downloading File 8)M .W  
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public SiteInfoBean() dD!} P$
 
{//nSplitter的缺省值为5 GyT{p#l  
//default value of nSplitter is 5 L,\ Yj  
this("","","",5); 9 ?h)U|J?G  
} P\w.:.2  
~|fd=E%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZW*"Kok  
{ O/0m|~`iY  
sSiteURL= sURL; fMhMB |W.  
sFilePath = sPath; [x,_0-_  
sFileName = sName; ud!iy  
this.nSplitter = nSpiltter; ^[d)Hk}L  
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{3`9A
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} Qm ;ip E  
m#DC;(Pn  
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public String getSSiteURL() K4A=lD+  
{ -/KVZ  
return sSiteURL; }1Q]C
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} fWF\V[  
4,TS1H  
D4;V8(w=#  
public void setSSiteURL(String value) 4l>/6LNMF  
{ kS3wa3bT  
sSiteURL = value; |o=eS&)  
} (CO8t~J=  
e9"<.:&  
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public String getSFilePath() [%z~0\lu8  
{ p@>_1A}qh_  
return sFilePath; "4}{Z)&R2  
} El]Rrku  
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public void setSFilePath(String value) ]J:?@}\^  
{ vsHY;[  
sFilePath = value; Gl`Yyw@84  
} kcM9 ,bG  
~vBmW_j  
t&H):P  
public String getSFileName() 8X[G)J;  
{ ZrXvR`bsw  
return sFileName; }3 RqaIY}  
} w/E4wp  
jZ7#xRt5w  
1k3wBc5<  
public void setSFileName(String value) \oLRNr[F  
{ oq(um:m  
sFileName = value; fQ'P2$  
} T&X*[kP  
 3
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P ;PS+S9  
public int getNSplitter() <eI7xifD  
{ v-2.OS<o  
return nSplitter; 2< w/GX.  
} _:?)2NV  
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public void setNSplitter(int nCount) ?_(0cVi  
{ G6]M~:<i  
nSplitter = nCount; q --NLm@;  
} &5)Kg%r  
} uhbo/7d'7  
`BdZqXKG  
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/* e(O"V3wq*6  
**Utility.java Jou~>0,/j  
*/ ,a~- (@  
package NetFox; ,3!l'|0jJ  
2_ <  
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public class Utility { @{j'Pf'  
{~.h;'m  
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public Utility() xbxU`2/  
{ v1 d]  
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} .zAB)rNc |  
h?p&9[e`  
//线程睡眠 A?06fo,  
public static void sleep(int nSecond) b6 &`]O;%  
{ w[qWr@
  
try{ wwF]+w%lOw  
Thread.sleep(nSecond); -e3m!h  
} \Se>u4~L  
catch(Exception e) MW &iNioX  
{ Ia*eb%HG  
e.printStackTrace (); rg]eSP3W  
} .ZJt  
} WJ9Jj69  
O~.A}  
//日志 M~t S *
 
public static void log(String sMsg) .Vj;[p8  
{ a*0gd-e0@  
System.err.println(sMsg); M\
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} B5hk]=Ud  
RAxAy{  
4E}]>  
public static void log(int sMsg) a.L ?J  
{ B9`nV.a  
System.err.println(sMsg); Cp7EJr~  
} dW Y0  
} RcitW;{|Kg  
-z)I;R  
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/* ~v$gk  
**TestMethod.java /Li?;H  
*/ *`YR-+0  
package NetFox; Lj6$?(x}  
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:PuJF`k  
public class TestMethod { BX;Z t9"*  
/!rH DcR  
=ltT6of@o  
public TestMethod() \b?z\bC56  
{ ///xx/weblogic60b2_win.exe 8q{ %n   
try{ *aT3L#0(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -bd
F=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lPFT)>(+@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z.Z+cFi  
fileFetch.start(); 2JwR?<n{  
} # kl?ww U  
catch(Exception e){e.printStackTrace ();} xG@zy4  
y((I2g1rv  
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} H]K(`)y}4  
2uu"0Rm%  
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public static void main(String[] args) N '2
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{ avrf]raM|  
new TestMethod(); i9+(gX(t  
} ,E2Tw-%  
} gf7%vyMo$  
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