http断点续传简单实现（java)

/* v4<W57oH  
**SiteFileFetch.java hr;^.a^
  
*/ ;plBo%EBV  
package NetFox; ![;={d0  
import java.io.*; M6mgJonN|  
import java.net.*; 1RJFPv  
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public class SiteFileFetch extends Thread { Q
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SiteInfoBean siteInfoBean = null; //文件信息Bean <o/!M6^:  
long[] nStartPos; //开始位置 b{qN7X~>  
long[] nEndPos; //结束位置 "I66@d?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~P#mvQE)  
long nFileLength; //文件长度 0N^+d,Xt.  
boolean bFirst = true; //是否第一次取文件 %cLS*=MO  
boolean bStop = false; //停止标志 jYi,oE  
File tmpFile; //文件下载的临时信息 C7ug\_,s  
DataOutputStream output; //输出到文件的输出流 $2\8Rn6'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hs[x\:
})/  
public SiteFileFetch(SiteInfoBean bean) throws IOException -nXP<v=V  
{ (P`=9+  
siteInfoBean = bean; V:w%5'^3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?TeozhUY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b3EGtC}^  
if(tmpFile.exists ()) vof8bQ{&  
{ -=nk,cYn  
bFirst = false; Ie(i1?`A8  
read_nPos(); &nDXn|  
} a
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else u8T@W}FX  
{ uLa
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nStartPos = new long[bean.getNSplitter()]; w%.hALN5-C  
nEndPos = new long[bean.getNSplitter()]; X8VBs#tLE  
} /i3JP}  
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} a;t}'GQGk  
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public void run() 3l%Qd<  
{ Ux7LN@4og  
//获得文件长度 Ez;Qo8  
//分割文件 JD#x+~pb,8  
//实例FileSplitterFetch [EDX@Kdq)  
//启动FileSplitterFetch线程 h<e  
//等待子线程返回 k?Z:=.YW  
try{ K_;vqi^1^&  
if(bFirst) tsAV46S  
{ H0;Iv#S!  
nFileLength = getFileSize(); 7Y9#y{v1  
if(nFileLength == -1) H}$7c`;q  
{ =}0Uw4ub(u  
System.err.println("File Length is not known!"); _;BwP  
} 1(-!TJ{  
else if(nFileLength == -2) pASX-
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{ 9a=Ll]=\  
System.err.println("File is not access!"); !\X9$4po@  
} x=t
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else qtExd~E  
{ C< 9x\JY%  
for(int i=0;i<nStartPos.length;i++) 2 ^m}5:0  
{ 6@s!J8!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f^FFn32u  
} 7pm'b,J<  
for(int i=0;i<nEndPos.length-1;i++) r }lGcG)  
{ N[po)}hp  
nEndPos = nStartPos[i+1]; k5I;Y:~`  
} d.FU))lmD  
nEndPos[nEndPos.length-1] = nFileLength; $AZYY\1  
} -g@!\{  
} m<h%BDSzr{  
/?eVWCR  
iM@$uD$_Q2  
//启动子线程 q#tUDxf(|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5p (zhfuG  
for(int i=0;i<nStartPos.length;i++) _K o#36.S  
{ C`hdj/!A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eR$@Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LH5Z@*0#  
nStartPos,nEndPos,i); }T@=I&g;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &eHRn_st5b  
fileSplitterFetch.start(); H)Btm  
} E`.xu>Yyj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5EFt0?G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2#>;cn\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hZx&j{  
nEndPos = " + nFileLength); |}z)>E  
// fileSplitterFetch[nPos.length-1].start(); )A\ ZS<@Z7  
wXKtQ#o}  
hq 3n&/  
//等待子线程结束 =]%JTGdp(  
//int count = 0; vN Bg&m  
//是否结束while循环 |NuMDVd+s  
boolean breakWhile = false; ~[HzGm%
  
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while(!bStop) ij ?7MP  
{ r{;NGQYs  
write_nPos(); yp#!$+a}  
Utility.sleep(500); PMfW;%I.  
breakWhile = true; 4yyw:"  
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for(int i=0;i<nStartPos.length;i++)  k,:W]KD  
{ )2&3D"V  
if(!fileSplitterFetch.bDownOver) tm+*ik=x|  
{ pey=zR!  
breakWhile = false; h} `v0E  
break; l=E86"m  
} 'JOUx_@z  
} ;7'O=%  
if(breakWhile) $Zu?Gd?  
break; +V4)><  
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//count++; l7|z]v-  
//if(count>4) qX,q*hr-  
// siteStop(); fz(YP=@ZnP  
} #EH=tJgO|J  
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System.err.println("文件下载结束！"); ON,[!pc  
} i#'K7XM2  
catch(Exception e){e.printStackTrace ();} MgeC-XQM  
} MgXZN{  
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//获得文件长度 MTu\T  
public long getFileSize() Sq5,}oT_{j  
{ '(.5!7?Qc  
int nFileLength = -1; h.edb6  
try{ TTXF r  
URL url = new URL(siteInfoBean.getSSiteURL()); w?ugZYwX*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NM{)liP ;8  
httpConnection.setRequestProperty("User-Agent","NetFox"); -8 uS#  
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int responseCode=httpConnection.getResponseCode(); Xdn&%5rI  
if(responseCode>=400) B4y_{V  
{ ZC?~RXL(  
processErrorCode(responseCode); t<45[~[  
return -2; //-2 represent access is error (Ceruo S  
} i!a!qE.1  
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String sHeader; )]fsl_Yq  
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U
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for(int i=1;;i++) |{#St-!-7  
{ Ok!P~2J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L]=]/>jQ6  
//Utility.log(in.readLine()); tx09B)0  
sHeader=httpConnection.getHeaderFieldKey(i); ji/`OS-iq  
if(sHeader!=null) }F>RIjj  
{ v3DK0MW  
if(sHeader.equals("Content-Length")) 2u]G]:ml  
{ ``/L18  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); % !@E)%d0  
break; jj{:=lZB  
} o<nM-"yWb  
} tK3$,9+  
else > "hP  
break; \l/(L5gY  
} d:'{h"M6  
} *$A`+D9  
catch(IOException e){e.printStackTrace ();} hkPMu@BI  
catch(Exception e){e.printStackTrace ();} hi(b\ABx  
5iw\F!op:  
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Utility.log(nFileLength); sX"L\v  
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return nFileLength; ~cm4e>o  
} $n<1D -0!r  
-b!?9T?}  
WO>,=^zPJ  
//保存下载信息（文件指针位置） gt8dFcm|s  
private void write_nPos() f#l9rV"@g  
{ ^&;,n.X5Z  
try{ K@p9_K8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^]o H}lwO  
output.writeInt(nStartPos.length); n/v.U,f&l@  
for(int i=0;i<nStartPos.length;i++) cxR.:LD}  
{ .rBU"Rbo  
// output.writeLong(nPos); 0Z2XVq~T$  
output.writeLong(fileSplitterFetch.nStartPos); ;-3&yQ7N)  
output.writeLong(fileSplitterFetch.nEndPos); X5o*8Bg4M  
} q7CLxv &QG  
output.close(); pLu5x<  
} aVR!~hvFs  
catch(IOException e){e.printStackTrace ();} "~VKUvDu  
catch(Exception e){e.printStackTrace ();} T={!/y+
 
} k~)CJ6}
 
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//读取保存的下载信息（文件指针位置） X@kgc&`0  
private void read_nPos() 1tY
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{ 6$OmOCA%  
try{ g%J\YRo  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9,8/DW.K  
int nCount = input.readInt(); FRxR/3&  
nStartPos = new long[nCount]; d./R;Z- I{  
nEndPos = new long[nCount]; jGouwta  
for(int i=0;i<nStartPos.length;i++) Jj)J5S /  
{ b}(c'W*z%  
nStartPos = input.readLong(); ;gL{*gR]S  
nEndPos = input.readLong(); mX>N1zAz  
} fgqCX:SWz  
input.close(); }k.yLcXM  
} 6"_pCkn;c<  
catch(IOException e){e.printStackTrace ();} 1L`V{\_0s  
catch(Exception e){e.printStackTrace ();} ,hf W2}  
} 6D| F1UFU  
f%PLR9Nh5@  
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private void processErrorCode(int nErrorCode) 3D6&0xTq  
{ B*:I-5  
System.err.println("Error Code : " + nErrorCode); &B5&:ib1D  
} d%I7OBBx@
 
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qUfoEpW2=6  
//停止文件下载 GLIY!BU<C  
public void siteStop() )&E]  
{  3*Q=)}  
bStop = true; </kuJh\  
for(int i=0;i<nStartPos.length;i++) 8GBKFNR8  
fileSplitterFetch.splitterStop();  j=pg5T  
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} vw>(JCR  
} ktPM66`b  
//负责部分文件的抓取 z4 =OR@ h  
**FileSplitterFetch.java }J?,?>Z  
*/ >-V632(/{o  
package NetFox; z 8M\(<  
E-^(VZ_Xj  
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import java.io.*; Ytc[ kp  
import java.net.*; 48z%dBmTT*  
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public class FileSplitterFetch extends Thread { uhj]le!  
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String sURL; //File URL 7:g_
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long nStartPos; //File Snippet Start Position [*u\S  
long nEndPos; //File Snippet End Position LL);Ym9d  
int nThreadID; //Thread's ID lV:feX  
boolean bDownOver = false; //Downing is over '+Jy//5?  
boolean bStop = false; //Stop identical v5@4|u3ds  
FileAccessI fileAccessI = null; //File Access interface 0Sk~m4fj(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;07$G+['  
{ Xl1%c7r.1  
this.sURL = sURL; kIa16m  
this.nStartPos = nStart; 9:g A0Z  
this.nEndPos = nEnd; _1RvK? ;.{  
nThreadID = id; E5A"sB   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3f$n8>mq  
} D5xQ  
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public void run() 5s\;7>  
{ |X*y-d77W  
while(nStartPos < nEndPos && !bStop) VMF?qT3Nd  
{ ]@21KO  
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try{ #
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URL url = new URL(sURL); vCej( ))  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 59$PWfi-\  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?7pn%_S  
String sProperty = "bytes="+nStartPos+"-"; > dVhIbG  
httpConnection.setRequestProperty("RANGE",sProperty); tq,^!RSbZ  
Utility.log(sProperty); #/Ob_~-?j  
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InputStream input = httpConnection.getInputStream(); >`3F`@1L0  
//logResponseHead(httpConnection); PSv 5tQhm  
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byte[] b = new byte[1024];  z9&j  
int nRead; Ax\d{0/oL2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t$,G%micj  
{ LmyaC2  
nStartPos += fileAccessI.write(b,0,nRead); Uc_}="  
//if(nThreadID == 1) g$2#TWW5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [;aM8N  
} /2d>nj  
1P"{TMd?  
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Utility.log("Thread " + nThreadID + " is over!"); ";`jS&"=  
bDownOver = true; \
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//nPos = fileAccessI.write (b,0,nRead); &Jb$YKt  
} IhK SwT  
catch(Exception e){e.printStackTrace ();} h}'Hst  
} Q=%W-  
} $bKXP(  
E@otV6Wk[@  
|AE{rvP{@  
//打印回应的头信息 @D*PO-s9  
public void logResponseHead(HttpURLConnection con) ud(0}[  
{ w%TrL+v  
for(int i=1;;i++) sZ&6g<8#y  
{ ts
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String header=con.getHeaderFieldKey(i); 2o9B >f&g  
if(header!=null) SJX9oVJeZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `-CN\  
Utility.log(header+" : "+con.getHeaderField(header)); {HM[ )t0  
else Jlb{1B$7  
break; <z%**gP~G  
} &-o5lrq  
} lb9?Uc@  
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f U=P$s  
public void splitterStop() AfhJ6cSIE  
{ aaf}AIL.  
bStop = true; f*"T]AX0  
} M`q|GY  
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} Dz$w6d  
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/* ZY7-.  
**FileAccess.java oB!Y)f6H1  
*//文件访问(定位，写) UkD\ma  
package NetFox; [O^/"Qk  
import java.io.*; d])ctxB  

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public class FileAccessI implements Serializable{ mzM95yQ^Z  
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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 T#!% Uzz  
RandomAccessFile oSavedFile; x ~)~v?>T  
long nPos; 4yqYs>  
XP!m]\E&I  
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public FileAccessI() throws IOException oDD"h,Z  
{ ><IWF#kUA  
this("",0); Opf)TAl{  
} 5*A5Y E-  
M0C)SU5"  
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public FileAccessI(String sName,long nPos) throws IOException re%XaL  
{ *szs"mQ/  
oSavedFile = new RandomAccessFile(sName,"rw"); 4P)#\$d:  
this.nPos = nPos; Sn'!Nq>  
oSavedFile.seek(nPos); j3%Wrt  
} A)!W VT&2A  
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RuVk>(?WK%  
public synchronized int write(byte[] b,int nStart,int nLen) "8ZV%%elp  
{ [~|k;\2 +  
int n = -1; >oyf i:  
try{ iNl<<0a  
oSavedFile.write(b,nStart,nLen); Z R=[@Oi  
n = nLen; 2uT6M%OC  
} UE5,Ml~X  
catch(IOException e) ";&PtLe  
{ YwY?tOxBe  
e.printStackTrace (); 0e#PN@  
} ; \co{_&D  
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return n; u=s,bt,"5  
} a""
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} Yz[Rl ^  
_8K8Ai-~.>  
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/* uA =%EEZ  
**SiteInfoBean.java ]Z\W%'q+  
*/ l}-k>fug  
package NetFox; ziO(`"v  
fX,O9d$  
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public class SiteInfoBean { A_ &IK;-go  
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[3S17tTc3  
private String sSiteURL; //Site's URL yp=sL' E  
private String sFilePath; //Saved File's Path h7K,q S  
private String sFileName; //Saved File's Name x4g6Qze  
private int nSplitter; //Count of Splited Downloading File or;VmU8$zb  
3j$,L(  
hmLI9TUe6  
public SiteInfoBean() Kc^ctAk7;  
{//nSplitter的缺省值为5 P%yL{  
//default value of nSplitter is 5 N GnE  
this("","","",5); bvZD@F`2  
} Zp_j\B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E>*b,^J7g  
{ n2AoEbd  
sSiteURL= sURL; KgD$P(J:[  
sFilePath = sPath; H*0g*(  
sFileName = sName; +RpCh!KP  
this.nSplitter = nSpiltter; zCA8}](C^  
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\,p?pL<'  
} )q4n
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1z2v[S&pk  
public String getSSiteURL() IN1n^f$:  
{ #2Q%sE?  
return sSiteURL; %j17QD8  
} |SMigSu r`  
#>_fYj
T  
}2BNy9q@  
public void setSSiteURL(String value) .
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{ s/~[/2[bnf  
sSiteURL = value; ? B|i  
} im:[ViR {  
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public String getSFilePath() KdHkX+-R  
{ g9g ]X  
return sFilePath; !(Y|Vm'  
} :u=y7[I  
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public void setSFilePath(String value) Fv/{)H<:y  
{ (qc<'$o  
sFilePath = value; oliVaavj  
} d^IX(y*$  
v\!Cq+lFML  
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public String getSFileName() {nA
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{ ~KGE(o4p  
return sFileName; "k [$euV  
} $[cB6  
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IWN18
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public void setSFileName(String value) S$wC{7?f  
{ VOATza`  
sFileName = value; ]NWcd~"b!Z  
} KU+u.J  
l&] %APL  
MB>4Y]rtU  
public int getNSplitter() Z *l&<q>#  
{ ~]W @+\l  
return nSplitter; u5U^}<}y}  
} d@Bd*iI<  
\Z%_dT}  
}Sh@.3*  
public void setNSplitter(int nCount) }\N ~%?6D  
{ {}" <  
nSplitter = nCount; qIzv|Nte  
} eK3d_bF+  
} 4T)`%Oo<}  
+['1~5  
8r,0Qic2K  
/* OaN"6Ge#  
**Utility.java ^eRbp?H*T  
*/ t?weD{O  
package NetFox; ]4*E:  
e*D,2>o  
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public class Utility { Pa|*Jcr  
>K%+h)%kI  
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public Utility() a{ByU%  
{ 9a1R"%Z  
\)MzUOZn  
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} V5jy,Qi)  
b|k(:b-G&.  
//线程睡眠 a[!:`o1U  
public static void sleep(int nSecond)  V2 ;?  
{ pnv)D}"  
try{ ESS1 L$y  
Thread.sleep(nSecond); +H? XqSC  
} ##] `  
catch(Exception e) KmD#I
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{ 9I1`*0A  
e.printStackTrace (); j{ri]?p  
} RSjcOQ8&.w  
} v]q"{c/  
O6q5qA  
//日志 VF<VyWFC0`  
public static void log(String sMsg) R\6dvd  
{ #N97  
System.err.println(sMsg); ^v3J ld  
} !.|A}8nK  
te>Op 1R  
x+Ly,9nc$  
public static void log(int sMsg) q?0&0  
{ 1yc$b+TH  
System.err.println(sMsg); [A;0IjKam  
} U:aaa  
} e&<=+\ul  
h)r=+Q\'(S  
QT"o"B  
/* .36]>8  
**TestMethod.java Ob|tA  
*/ xCu\jc)2  
package NetFox; ~!Rf5QA85  
b|.<rV'BTt  
B-$ps=G+z  
public class TestMethod { }qhND-9#@  
_#<7s`i  
ZZeF1y[q  
public TestMethod() f_.0 uM  
{ ///xx/weblogic60b2_win.exe [&p/7  
try{ |L <  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #J$z0%P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j  W-K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~\O,#j`_  
fileFetch.start(); 'L%)B-,n  
} [hiV#  
catch(Exception e){e.printStackTrace ();} - l0X]&Ex  
<Um5w1  
cw~-%%/  
} Ige*tOv2  
RE;)#t?K  
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public static void main(String[] args) m]VOw)mBF  
{
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new TestMethod(); *W4~.peoE  
} V67<Ky>  
} pvM`j86 _  
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