http断点续传简单实现（java)

/* 7lV.[&aKW  
**SiteFileFetch.java >NYW{(j  
*/ s\!>"J bAQ  
package NetFox; #$1Z
 
import java.io.*; k:jSbbQ  
import java.net.*; 4}+/F}TbJ5  
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public class SiteFileFetch extends Thread { HY)-/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZKHG!`X0  
long[] nStartPos; //开始位置 pRkP~ZISU  
long[] nEndPos; //结束位置 @)o^uU T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fU=B4V4@  
long nFileLength; //文件长度 RuII!
}*  
boolean bFirst = true; //是否第一次取文件 cufH?Xg<  
boolean bStop = false; //停止标志 UMAgA!s  
File tmpFile; //文件下载的临时信息 Zm6{n'  
DataOutputStream output; //输出到文件的输出流 p w8 s8?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9IX/wm"  
public SiteFileFetch(SiteInfoBean bean) throws IOException lXcx@
#~  
{ 3EJt%}V$k  
siteInfoBean = bean; :VTTh |E%#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ns6(cJ^a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xJ#d1[kzo  
if(tmpFile.exists ()) J8mdoVt  
{ SkmT`*v@  
bFirst = false; dFKM 8_jH  
read_nPos(); ^0/j0]O  
} 0$,SF3K  
else ZK>WW  
{ 15o9 .   
nStartPos = new long[bean.getNSplitter()]; 0PlO(",a  
nEndPos = new long[bean.getNSplitter()]; B95B|tU>.  
} /!c${W!sY  
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} #O+),,WS  
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public void run() yu;P +G  
{ xg3:}LQ  
//获得文件长度
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//分割文件 Oil?JI Hq  
//实例FileSplitterFetch ZIQ [bE7  
//启动FileSplitterFetch线程 hEp(A8g)bQ  
//等待子线程返回 uD^cxD  
try{ yU9DSY\m{  
if(bFirst) Z<vKQ4G  
{ tCdqh- 
 
nFileLength = getFileSize(); ZpnxecJUJ  
if(nFileLength == -1) 1fpQLaT  
{ H'  
System.err.println("File Length is not known!"); UEguF&  
} ljb7oA3cP4  
else if(nFileLength == -2) =>_\fNy  
{ m6w].-D8  
System.err.println("File is not access!"); u fw]=h)  
} 9Gnc9_]I;W  
else \SBc;  
{ b:TLV`>/&  
for(int i=0;i<nStartPos.length;i++) N<XNTf  
{ E"5*Ei)^3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U H*r5o3  
} d~i+ I5  
for(int i=0;i<nEndPos.length-1;i++) NfjE`  
{ [5SD_dN  
nEndPos = nStartPos[i+1]; >Z'NXha  
} R=QZgpR  
nEndPos[nEndPos.length-1] = nFileLength; hpD!2 K3>  
} 'h,VR=e<  
} `Tv[DIVW  
"$YJX1u3  
|>dI/_'  
//启动子线程 =w{Z@S(ukz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?`PvL!'  
for(int i=0;i<nStartPos.length;i++) lE4HM$p
 
{ $w`=z<2yo1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =`H@%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NU5.o$  
nStartPos,nEndPos,i); OG>}M$Ora  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,,q10iF  
fileSplitterFetch.start(); toBHkiuD  
} &7K?
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8ap%?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7_inJ$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v@ lM3_rbO  
nEndPos = " + nFileLength); -#N.X_F  
// fileSplitterFetch[nPos.length-1].start(); VgZsB$Ori  
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@eKec1<  
//等待子线程结束 ddJe=PUb  
//int count = 0; ! t?iXZ  
//是否结束while循环 :%,:"  
boolean breakWhile = false; Ezd_`_@R  
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wNpTM8rfU#  
while(!bStop) Y,^@P  
{ CDK5  
write_nPos(); !xo{-@@wS  
Utility.sleep(500); /}b03  
breakWhile = true; rrik,qyv6  
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for(int i=0;i<nStartPos.length;i++) c7x~{V8  
{ 4R1<nZ"e~  
if(!fileSplitterFetch.bDownOver) j i7[nY  
{ Lr~=^{  
breakWhile = false; ix)M`F%P3  
break; $QN"wL||  
} 4NheWM6  
} svcK?^ HTe  
if(breakWhile) 5YeM%%-S  
break; BBwy,\o#  
 3KlbP  
128EPK  
//count++; Whm,F^  
//if(count>4) ) l:[^$=,  
// siteStop(); uKUiV%p!  
} g| I6'K!<  
$
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System.err.println("文件下载结束！"); N"Zt47(  
} 0"  
catch(Exception e){e.printStackTrace ();} $_"'&zQ'  
} 7q?, ?  
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//获得文件长度 hKL4cpK4  
public long getFileSize() 1\ o59
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{ Yg%I?  
int nFileLength = -1; sBvzAVBL  
try{ ;-~B)M_S`  
URL url = new URL(siteInfoBean.getSSiteURL()); tE<H|_{L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3no%E03p  
httpConnection.setRequestProperty("User-Agent","NetFox"); `T@i.'X  
Lt?lv2k=L  
gmw|H?]  
int responseCode=httpConnection.getResponseCode(); cQCSe,$ W  
if(responseCode>=400) G|!Tj X7s  
{ |"ls\ 7  
processErrorCode(responseCode); qouhuH_WtJ  
return -2; //-2 represent access is error Z'`<5A%;  
} 0l)~i''  
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String sHeader; zy/@ WFPE  
A5c%SCq;
 
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for(int i=1;;i++) +Vb.lH[av  
{ LDgrR[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rr&h!YMb  
//Utility.log(in.readLine()); JjtNP)We  
sHeader=httpConnection.getHeaderFieldKey(i); ,<(}|go  
if(sHeader!=null) :}'=`wa  
{ >%}C^gu)  
if(sHeader.equals("Content-Length")) 6m*QX+  
{ 3]}D`Qs6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %?0:vn  
break; %9KldcQ}~  
} N7b8m?!  
} {f3YsM;]C  
else 3%#3iZ=_  
break; X5zDpi|Dq  
} I8
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} Aza /6OL  
catch(IOException e){e.printStackTrace ();} dk[!V1x4\  
catch(Exception e){e.printStackTrace ();} yj 3cyLXw  
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Utility.log(nFileLength); oK6tTK  
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return nFileLength; xgVeN["  
} aL+ o /  
<=zQ NBtx  
n\Z!ff/  
//保存下载信息（文件指针位置） ,>bh$|  
private void write_nPos() SA&Rep^  
{ kJ'
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try{ :;t:H] f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^me-[ 5  
output.writeInt(nStartPos.length); 0fb2;&pUa  
for(int i=0;i<nStartPos.length;i++) sEp"D+f  
{ b[r8e  
// output.writeLong(nPos); PCHu#5j_a  
output.writeLong(fileSplitterFetch.nStartPos); w1Nm&}V  
output.writeLong(fileSplitterFetch.nEndPos); g0xuxK;9c  
} "h{q#~s  
output.close(); hO\<%0F  
} .F4>p=r  
catch(IOException e){e.printStackTrace ();} 1F5XvQl  
catch(Exception e){e.printStackTrace ();} cM(:xv  
} OcR$zlgs[v  
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//读取保存的下载信息（文件指针位置） x[FJgI'r  
private void read_nPos() ~Z\8UsVN  
{ c,np2myd  
try{ u@Ih GME  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :
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int nCount = input.readInt(); I:R[;TB?y  
nStartPos = new long[nCount];  ~^NtO  
nEndPos = new long[nCount]; u1J0$  
for(int i=0;i<nStartPos.length;i++) w$3,A$8  
{ .0zY}`  
nStartPos = input.readLong(); z`.<U{5  
nEndPos = input.readLong(); pNG:0  
} $t$Sh
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)  
input.close(); y;35WtDVb  
} .[]r}[lU  
catch(IOException e){e.printStackTrace ();} X&tF;<m^  
catch(Exception e){e.printStackTrace ();} Z;ht  
} Q- cFtu-w  
((YMVe  
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private void processErrorCode(int nErrorCode) :}He\V  
{ 9P1OP Xv*p  
System.err.println("Error Code : " + nErrorCode); +SP{hHa^  
} nHM
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//停止文件下载 (ZS}G8  
public void siteStop() ]FJjgu<  
{ 2,DXc30I  
bStop = true; lp.ldajN  
for(int i=0;i<nStartPos.length;i++) K^ vIUZ>  
fileSplitterFetch.splitterStop(); Kfbb)?  
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} C8J[Up  
} 1T"`vtR  
//负责部分文件的抓取 F|'>NL-=  
**FileSplitterFetch.java $njUXSQ;  
*/ S3q&rqarC%  
package NetFox; XQY#716)  
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import java.io.*; %^?fMeI|Y  
import java.net.*;
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public class FileSplitterFetch extends Thread { a!zz6/
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String sURL; //File URL Zd3S:),&  
long nStartPos; //File Snippet Start Position 2Z+Wu3#  
long nEndPos; //File Snippet End Position |6.l7u?d  
int nThreadID; //Thread's ID p2hB8zL  
boolean bDownOver = false; //Downing is over RVZ")Z(  
boolean bStop = false; //Stop identical $h+1u$po  
FileAccessI fileAccessI = null; //File Access interface J4k=A7^N  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GB23\
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{ >@U*~Nz  
this.sURL = sURL; 6|gCuT4  
this.nStartPos = nStart; 6LvW?z(J  
this.nEndPos = nEnd; 8EZ$g<}  
nThreadID = id; 0CZ:Bo[3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g{7.r-uu  
} Xc=Y  
MU($|hwiL  
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public void run() qEyyT[:  
{ %vn|k[nD  
while(nStartPos < nEndPos && !bStop) 'f#{{KA  
{ ts,ZvY]  
3OrczJ=[UF  
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try{ G0CW}e@)  
URL url = new URL(sURL); +>8'mf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xipU8'ac/  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jz\%%C  
String sProperty = "bytes="+nStartPos+"-"; 6gL#C&  
httpConnection.setRequestProperty("RANGE",sProperty); C(eTR1  
Utility.log(sProperty); 5Y.)("1f}f  
4R#chQ  
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InputStream input = httpConnection.getInputStream(); D
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//logResponseHead(httpConnection); BnX0G1|#  
Z-$[\le  
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byte[] b = new byte[1024]; )cW#Rwu_A4  
int nRead; gt\E`HB8E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uFX#`^r`  
{ yks__ylrl(  
nStartPos += fileAccessI.write(b,0,nRead); _mj,u64  
//if(nThreadID == 1) Yz'K]M_Dq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WQx?[tW(U  
} TtK[nP  
~Zun&b)S  
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Utility.log("Thread " + nThreadID + " is over!"); ;nI] !g:  
bDownOver = true; F3y9@dA]  
//nPos = fileAccessI.write (b,0,nRead); /,BD#|  
} zUt'QH7E.  
catch(Exception e){e.printStackTrace ();} h8x MI  
} AgWa{.`f:  
} 2A']yD  
+=>,Pto<  
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//打印回应的头信息 gI&#o@Pm  
public void logResponseHead(HttpURLConnection con) e+=y*OmQ  
{ d8DV[{^  
for(int i=1;;i++) f- K+]aZ)  
{ @#l `iK  
String header=con.getHeaderFieldKey(i); w_aknt T  
if(header!=null) \q>bs|2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DRSr%d  
Utility.log(header+" : "+con.getHeaderField(header)); RaO-H  
else =
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break; t0(A4E  
} MH =%-S   
} FDv<\2+ c  
6{@w="VT  
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public void splitterStop() 1;JEc9#h  
{ l94b^W}1)W  
bStop = true; 2VPdw@"~}  
} 55G+;  
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} I~[F|d>  
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H/"-Z;0{  
/* vRznw&^E
 
**FileAccess.java q?H|o(  
*//文件访问(定位，写) Ve8=b0&Y#j  
package NetFox; 2pZXZ  
import java.io.*; R &nPj~  
DKH-Q(M56  
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public class FileAccessI implements Serializable{ d.[8c=$  
#?RU;1)Cw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 b\ X@gq  
RandomAccessFile oSavedFile; ~]nRV *^  
long nPos; ;p.v]0]is  
\|n- O=}=2  
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public FileAccessI() throws IOException *~2,/D  
{ XP`Nf)3{Yd  
this("",0); _Mi5g_  
} j9m_jv  
~Q*%DRd&Z-  
7( #:GD  
public FileAccessI(String sName,long nPos) throws IOException T*I{WW  
{ ]q\b,)4 e  
oSavedFile = new RandomAccessFile(sName,"rw"); <c*FCblv  
this.nPos = nPos; 4aug{}h("  
oSavedFile.seek(nPos); [Hx0`Nc K  
} 0}<|7?  
3t.l5m Rg5  
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public synchronized int write(byte[] b,int nStart,int nLen) #^#PP
O  
{ CVDV)#JA  
int n = -1; 36.Z0Z1'F>  
try{ ke!?BZx  
oSavedFile.write(b,nStart,nLen); 'Oxy$U   
n = nLen; MO[2~`,Q!  
} q~rEq%tk  
catch(IOException e) ]yV!  
{ )"qa kT  
e.printStackTrace (); c& <Fr[AK  
} *$#W]bO  
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return n; "x%Htq@  
} _qU4Fadgm  
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} zlyS}x@p  
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( B!uy`  
/* <xup'n^7C  
**SiteInfoBean.java "WlZ)wyF%  
*/ ~cWAl,(B<F  
package NetFox; %Celc#v  
Ii6<b6-  
AWcLUe{  
public class SiteInfoBean { p}&#jE  
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P)"noG_'i  
private String sSiteURL; //Site's URL C^s^D:   
private String sFilePath; //Saved File's Path {baq+  
private String sFileName; //Saved File's Name =NpYFKmMhV  
private int nSplitter; //Count of Splited Downloading File FW.7'7G@n  
z Eq GD2"  
57aXQ8u{  
public SiteInfoBean() XFg9P}"  
{//nSplitter的缺省值为5 m)8BgCy  
//default value of nSplitter is 5 v0ujdp,B  
this("","","",5);  vx\r!]  
} # q~e^A b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?yZ+D z\  
{ N%kt3vmQ_  
sSiteURL= sURL; zofa-7'Bn  
sFilePath = sPath; toLV4BtIG  
sFileName = sName; hZdoc<  
this.nSplitter = nSpiltter; :v0U|\j8/V  
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f0A{W/0n  
} 'SO %)B  
:8I9\eet3  
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public String getSSiteURL() P|^f0Rw3.  
{ 09|K>UC)v  
return sSiteURL; i
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} #TeG-sFJg@  
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public void setSSiteURL(String value) w2;eh]k  
{ AmvEf  
sSiteURL = value; }\hVy(\c  
} x`U^OLV  
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t

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public String getSFilePath() .>q8W  
{ .rO]M:UY  
return sFilePath; S3F;(PDzy  
} r~E=4oB7  
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#[,IsEpDO1  
public void setSFilePath(String value) >c1!p]&V  
{ I*o
()  
sFilePath = value; z[LNf.)}  
} 5rwu!Y;7*  
"C}
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public String getSFileName() 0[
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{ ;"KJ7p  
return sFileName; mkMq  
} yu;+o3WlK  
t!*?dr  
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public void setSFileName(String value) cT<1V!L4  
{ %huRsQ%}  
sFileName = value; +Um( h-;  
} *e<[SZzYZ  
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public int getNSplitter() t,QyfN  
{ bT\1>  
return nSplitter; ]}*R|1  
} IW>T}@ |  
;t'5},(FP  
7zA'ri3w  
public void setNSplitter(int nCount) 8R2QZXJb-  
{ Jy^u?  
nSplitter = nCount; cU RkP`  
} "/)#O
~  
} 
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2!0c4a^z  
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/* M:XSQ["6>V  
**Utility.java U [*FCD!~  
*/ VE#Wb7  
package NetFox; c(J!~7  
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public class Utility { c$ao:nP)D  
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public Utility() FFV `P  
{ U}&
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1j
CLO}  
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} $Oq^jUJ  
5)FJ:1-  
//线程睡眠 j`oy`78O  
public static void sleep(int nSecond) tU4s'J  
{ 3XL#0\im?s  
try{ Qr1"Tk7s  
Thread.sleep(nSecond); mIurA?&7!  
} ^]7}YF2|  
catch(Exception e) (^s>m,h  
{ H+1-]'g`  
e.printStackTrace (); ,X#2\r<|  
} 9G9fDG#F\I  
} "k/;[ Wt]  
`q?8A3A  
//日志 BZ:H`M`n  
public static void log(String sMsg) --PtZ]Z  
{ %4ePc-  
System.err.println(sMsg); gMY1ts}Z  
} Lilr0|U+  
l%[EXZ  
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public static void log(int sMsg) lU
@]@_<  
{ Xp >7iX!:  
System.err.println(sMsg); u&`XB|~  
} I2TaT(e\  
} `JOOnTenQ  
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/* @$lG@I,[  
**TestMethod.java <Pap
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*/ 8s"%u )  
package NetFox; Q(lo{AFc  
uZM{BgXXD  
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public class TestMethod { fhar&\
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>Nvjl~o5  
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public TestMethod() :QpuO1Gu  
{ ///xx/weblogic60b2_win.exe ^?U!pq-`  
try{ s8wmCzB~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i'4B3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w,w{/T+B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j:5=s%S  
fileFetch.start(); :ZTc7}  
} :axRoRg  
catch(Exception e){e.printStackTrace ();} xGu r  
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} !;0U,!WI  
9 TvV=  
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public static void main(String[] args) Rec6c&5_  
{ }vZ+A
 
new TestMethod(); 1KMLG=  
} y&Mr=5:y  
} W{%TlN  
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