http断点续传简单实现（java)

/* 8J>s|MZ  
**SiteFileFetch.java tewC *%3V  
*/ e}Db-7B_~  
package NetFox; +4@EJRC  
import java.io.*; a|OX
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import java.net.*; 1|Fukx<@J<  
? 1_*ct=g9  
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public class SiteFileFetch extends Thread { 0uj3kr?cv  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k6$.pCH6  
long[] nStartPos; //开始位置 ;ASlsUE\)  
long[] nEndPos; //结束位置 OpiN,>;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 **oN/5  
long nFileLength; //文件长度 "EA%!P:d,  
boolean bFirst = true; //是否第一次取文件 d^,u"Z9P  
boolean bStop = false; //停止标志 _RAPXU~ 6-  
File tmpFile; //文件下载的临时信息 b2ZKhS8  
DataOutputStream output; //输出到文件的输出流 VRT| OUq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4Sw)IU~K(  
public SiteFileFetch(SiteInfoBean bean) throws IOException ['{mW4i  
{ 0Pbv7)=XL  
siteInfoBean = bean; 6)Kg!.n%f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _57i[U r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }2G'3msx  
if(tmpFile.exists ()) ?*Jv&f#  
{ &,bJ]J)8O  
bFirst = false; !x&/M*nBE  
read_nPos(); B1\}'g8%f  
} Yz[^?M%(D  
else 3>-^/  
{ +$P0&YaQ  
nStartPos = new long[bean.getNSplitter()]; n)[{nkS6[  
nEndPos = new long[bean.getNSplitter()]; )f,iey\-  
} }+,;wj~  
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} 
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public void run() `n$pR8TZ_  
{ LKTIwb>  
//获得文件长度 ss.wX~I  
//分割文件 ^Qq_|{vynf  
//实例FileSplitterFetch IL&Mf9m  
//启动FileSplitterFetch线程 YGN
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//等待子线程返回 4OC^IS  
try{ jsjH.O  
if(bFirst) *i&ks>4N  
{ +Y6=;*j$  
nFileLength = getFileSize(); 7]62=p2R  
if(nFileLength == -1) ]w"r4HlCx  
{ 0)+F}SyyD  
System.err.println("File Length is not known!"); 0]fzjiaGt  
} 3+0$=ef  
else if(nFileLength == -2) ~CQsv`
 
{ /n&w|b%  
System.err.println("File is not access!"); +q6/'ErN]m  
} ]haZT\  
else &KmVtj  
{ }[\l$sS  
for(int i=0;i<nStartPos.length;i++) xZwG@+U=X  
{ o^}K]ML!t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0p)#!$  
} $@s&qi_&R  
for(int i=0;i<nEndPos.length-1;i++) 2ntL7F<ow  
{ 9-5H~<}fF  
nEndPos = nStartPos[i+1]; 4v_<<l  
} &Y4S[-   
nEndPos[nEndPos.length-1] = nFileLength; %`?IY<  
} **N{XxdN  
} krFuEaO  
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//启动子线程 [RoOc)u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W9+H/T7!  
for(int i=0;i<nStartPos.length;i++) >^=upf/  
{ 'pa[z5{k+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;p)RMRMg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3rBSwgRl  
nStartPos,nEndPos,i); gY|f[M|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \!x~FVA  
fileSplitterFetch.start(); oSq?.*w<  
} ~=67#&(R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bnIl@0Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yS'W ss  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K&3,J
7&&  
nEndPos = " + nFileLength); ^ ~'&K e  
// fileSplitterFetch[nPos.length-1].start(); '1+s^Q'pc  
 d|;S4m`  
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//等待子线程结束 L7VDZCV  
//int count = 0; $KHw=<:)/  
//是否结束while循环 >"5f B  
boolean breakWhile = false; qQ6rF nA  
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while(!bStop) `ECY:3"$KA  
{ {%Cb0Zh  
write_nPos(); 41Ga-0p  
Utility.sleep(500); w`KqB(36  
breakWhile = true; 2@~.FBby7@  
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for(int i=0;i<nStartPos.length;i++) kD;1+lNz  
{ wIQ~a  
if(!fileSplitterFetch.bDownOver) Cw$0XyO  
{ n/9.;9b$I  
breakWhile = false; 1*U)\vK~  
break; UI2TW)^
2  
} 08czP-)OZ  
} MD|T4PPz,}  
if(breakWhile) Z uFk}R"x  
break; *uW l 804  
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//count++; w.X MyHj  
//if(count>4) 1V ,Mk#_  
// siteStop(); 7M8oI.?C|  
} yzyBr1s  
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N> 7sG(!'"  
System.err.println("文件下载结束！"); A#7/,1h\  
} vbBNXy/  
catch(Exception e){e.printStackTrace ();} ahICx{hK  
} NVnId p  
L!;"73,&(8  
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//获得文件长度 05>mRqVL  
public long getFileSize() YN]xI  
{ 'Dn\.x^]1  
int nFileLength = -1; [J!jp&o  
try{ ~F"<Nq  
URL url = new URL(siteInfoBean.getSSiteURL()); @6lw_E_5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *qa.hqas  
httpConnection.setRequestProperty("User-Agent","NetFox"); r{cmw`WA/P  
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int responseCode=httpConnection.getResponseCode(); I4XnJ[N%  
if(responseCode>=400) baQORU=X  
{ /Fk]>|*  
processErrorCode(responseCode); ~%chF/H
 
return -2; //-2 represent access is error _"%hcCMw  
} d4~;!#<  
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String sHeader; \+)aYP2Hu  
+$}3=n34)  
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for(int i=1;;i++) |`|#-xu  
{ %?`O .W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z)&!ZlM  
//Utility.log(in.readLine()); ='vD4}"j  
sHeader=httpConnection.getHeaderFieldKey(i); Ko|m<;LX  
if(sHeader!=null) .} O@<t  
{ 8$F"!dc _  
if(sHeader.equals("Content-Length")) ty8>(N(~  
{ w!dgIS$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d88Dyzz  
break; +0ALO%G;G"  
} _`I}"`2H  
} v!`:{)2C  
else &HQ_e$1  
break; $PstE
L  
} TMsc5E  
} %lk^(@+ T  
catch(IOException e){e.printStackTrace ();} DFkDlx  
catch(Exception e){e.printStackTrace ();} I A%ZCdA;  
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Utility.log(nFileLength); skm~~JM^  
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return nFileLength; GaCRo7  
} $Ge0<6/  
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//保存下载信息（文件指针位置） <z#.J]  
private void write_nPos() a<0q%Ax  
{ a&Qr7tTY"  
try{ /3#h]5Y"T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0GlQWRa  
output.writeInt(nStartPos.length); sWmqx$  
for(int i=0;i<nStartPos.length;i++) aUF{57,<  
{ eQz.N<f"  
// output.writeLong(nPos); c/7}5#Rs  
output.writeLong(fileSplitterFetch.nStartPos); gR+P!Eow  
output.writeLong(fileSplitterFetch.nEndPos); Mkh/+f4  
} [_eT{v2B4  
output.close(); )&DsRA7v  
} {,!!jeOO  
catch(IOException e){e.printStackTrace ();} 0bpGPG's&  
catch(Exception e){e.printStackTrace ();} #<~oR5ddlb  
} *>/w,E]  
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//读取保存的下载信息（文件指针位置） <0VC`+p<)  
private void read_nPos() ihJ!]#Fbm  
{ ch2m Ei(  
try{ +DG-MM%\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w\mTug  
int nCount = input.readInt(); mGDy3R90  
nStartPos = new long[nCount]; E-%$1=;  
nEndPos = new long[nCount]; R$!]z(  
for(int i=0;i<nStartPos.length;i++) 2Wg:eh  
{ <BIQc,)2}  
nStartPos = input.readLong(); ;m7~!m)  
nEndPos = input.readLong(); {qGXv@ I6  
} rd>>=~vx=/  
input.close(); :t9
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} ?V}ub>J/=  
catch(IOException e){e.printStackTrace ();} o|u4C{j  
catch(Exception e){e.printStackTrace ();} 'qUM38s  
} 9M^5<8:  
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private void processErrorCode(int nErrorCode) JMk2OK{0  
{ 8[.&ca/[  
System.err.println("Error Code : " + nErrorCode); QLU <%w:B  
} 2ql)]Skg6  
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);T&pm:C>  
//停止文件下载 TMD\=8Na  
public void siteStop() <"K2t Tg.  
{ n=)LB& m  
bStop = true; zB`J+r;LU  
for(int i=0;i<nStartPos.length;i++) pP#D*hiP-g  
fileSplitterFetch.splitterStop(); mU(v9Jpf7  
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} 7O8 @T-f+2  
} $}IG+,L  
//负责部分文件的抓取 $vK,Gugcx  
**FileSplitterFetch.java  _X  
*/ .Tm.M7  
package NetFox; rg;4INs#  
\[qxOZ{  
%y\5L#T!>  
import java.io.*; uF|Up]Z G  
import java.net.*; AFM+`{Cq  
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public class FileSplitterFetch extends Thread { }z#M!~  
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String sURL; //File URL FA>.1EI  
long nStartPos; //File Snippet Start Position n&o"RE 0~0  
long nEndPos; //File Snippet End Position t*; KxQ+'?  
int nThreadID; //Thread's ID &^K(9"  
boolean bDownOver = false; //Downing is over :Tv>)N  
boolean bStop = false; //Stop identical R:(i}g<3  
FileAccessI fileAccessI = null; //File Access interface .N>*+U>>P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o=#ym4hJ%  
{ Z"'*A\r2  
this.sURL = sURL; S(U9Dlyarg  
this.nStartPos = nStart; #>HY+
;  
this.nEndPos = nEnd; d2NFdBoI  
nThreadID = id; j/Y]3RSMp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `mW~{)x  
} @U3z@v]s(h  
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public void run() pouXt-%2X  
{ q.
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while(nStartPos < nEndPos && !bStop) /P-#y@I  
{ l.]wBH#RS  
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try{ r7].48D  
URL url = new URL(sURL); 5!S#}=f=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +}1zw<  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,\X!
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String sProperty = "bytes="+nStartPos+"-"; 2z"<m2a  
httpConnection.setRequestProperty("RANGE",sProperty); q5S_B]|  
Utility.log(sProperty);  Q
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InputStream input = httpConnection.getInputStream(); %WKBd\O  
//logResponseHead(httpConnection); y$bY 8L  
(J.Z+s$:2  
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byte[] b = new byte[1024]; L1I1SFG  
int nRead; YlUh|sK7m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !q,7@W3i  
{ }apno|W&  
nStartPos += fileAccessI.write(b,0,nRead); k H<C9z2=  
//if(nThreadID == 1) XN6$TNsD$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1<Mb@t  
} < qab\M0W  
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Utility.log("Thread " + nThreadID + " is over!"); Y3~z#<  
bDownOver = true; K?[Vz[-Fc  
//nPos = fileAccessI.write (b,0,nRead); }y+Qj6dP  
} ZA. SX|m  
catch(Exception e){e.printStackTrace ();} 1ig*Xp[  
} 
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} `L 1+j  
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//打印回应的头信息 ykJ+LS{+  
public void logResponseHead(HttpURLConnection con) JNXzZ4U  
{ %7 yQ0'P  
for(int i=1;;i++) ,u^{zYoW  
{ rv(N0p/  
String header=con.getHeaderFieldKey(i); aem gGw<  
if(header!=null) R`DzVBLl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kr~n5WiAZ  
Utility.log(header+" : "+con.getHeaderField(header)); boCi*]  
else R4VX*qkB  
break; 5@r6'Z  
} u-y?i`  
} K> 4w
 
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public void splitterStop() X<.l(9$  
{ $0K@=7ms  
bStop = true; %XeN_ V  
} <uS/8MP{  
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} G/FDD{y  
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/* WkE="E}  
**FileAccess.java Li|~%E1  
*//文件访问(定位，写) ZzgzeT+bv  
package NetFox; YkMFU'?[  
import java.io.*; 0Fon`3(^\  
2)}*'_
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public class FileAccessI implements Serializable{ mRC3w(W  
-6I*k |%8T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EVZ1Z  
RandomAccessFile oSavedFile; `pCy:J?d>l  
long nPos; LTzdg >\oJ  
@v@F%JCZ  
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public FileAccessI() throws IOException hKN ;tq,  
{ C P&u  
this("",0); lEwQj[ k  
} `:~Wu/Ogr  
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public FileAccessI(String sName,long nPos) throws IOException M&hNkJK*G  
{ 'R'hRMD9o  
oSavedFile = new RandomAccessFile(sName,"rw"); d7G@Z|R3p  
this.nPos = nPos; f42F@M(:  
oSavedFile.seek(nPos); R_g(6l"3R^  
} UP)<(3YA  
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public synchronized int write(byte[] b,int nStart,int nLen) Ri`6X_xU  
{ Mb[4_D
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int n = -1; @$^4Av-  
try{ $.
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oSavedFile.write(b,nStart,nLen); 5EVypw?]x  
n = nLen; hZ>m:es  
} }ri
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catch(IOException e) 6@/k|t>OT  
{ 7- LjBlH  
e.printStackTrace (); MG.c`t/w  
} l#T%N@
X  
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Or?c21un  
return n; )V>OND  
} |hi,]D^Kc  
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} T-STM"~%  
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/* z8"1*V  
**SiteInfoBean.java ?t6wozib2  
*/ e~(e&4pb  
package NetFox; [o(!/38"@=  
\6/Gy!0h-  
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public class SiteInfoBean { 2bw), W  
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private String sSiteURL; //Site's URL h x5M)8#+  
private String sFilePath; //Saved File's Path "\}h  
private String sFileName; //Saved File's Name /{[<J<(8  
private int nSplitter; //Count of Splited Downloading File `S-l.zSZ4B  
-V~Fj~b#  
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public SiteInfoBean() P/[RH e  
{//nSplitter的缺省值为5 N;-%:nC  
//default value of nSplitter is 5 M6Xzyt|  
this("","","",5); F7b% x7b  
} H{N},B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xr8fmJtg'  
{ ackeq#  
sSiteURL= sURL; ]ke9ipj]:  
sFilePath = sPath; Ths~8{dMb  
sFileName = sName; dwUDhQt3Q  
this.nSplitter = nSpiltter; pT~3< ,  
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} jLMy27Cn  
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public String getSSiteURL() rf
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{ xgkCN$zQ`  
return sSiteURL; VKYljY0#  
} J[Mj8ee#  
f2o6GC_  
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public void setSSiteURL(String value) I9xu3izAmR  
{ F[jqJzCz  
sSiteURL = value; p8-$MF]]6  
} [!3cWJCt  
3!sZA?q  
+I
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public String getSFilePath() c C) <Y#1  
{ 8|\ -(:v  
return sFilePath; jP}Ry=V/  
} h
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kiyKL:6D|  
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public void setSFilePath(String value) >+;}"J
 
{ H$^9#{  
sFilePath = value; `#!>}/m  
} IaRwPDj6  
%1#|>^  
.+?]"1>]  
public String getSFileName() ac@\\2srV  
{ Lh-Y5(c o  
return sFileName; %qeNC\6N  
} #"TYk@whWf  
Wql=PqF  
jp~Tlomp  
public void setSFileName(String value) N`H`\+  
{ ZvC?F=tH  
sFileName = value; P<[) qq@;  
} /5epDDP-t5  
]xb2W~  
p(4B"[!S  
public int getNSplitter() Vx5fQ mx  
{ ? ][/hL@[  
return nSplitter; lF46W  
} vg X7B4  
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A4d3hF~l`  
public void setNSplitter(int nCount) n++

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{ b"td]H3h  
nSplitter = nCount; h?4EVOx+  
} MZX@Gi<S[  
} N(J#<;!yb  
>OjK0jiPf  
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/* =\i%,YY  
**Utility.java x2b t^!t.  
*/ D]'8BS3  
package NetFox; Y37qjV  
c;yp}k]\  
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public class Utility { ) R5[aO  
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%|R]nB  
public Utility() A+\rGVNH'S  
{ M[iWWCX  
C\bJ_vl;'  
J=O_nup6C  
} 4/S3hH  
HG5E,^1n  
//线程睡眠 fL'Ci;.;+  
public static void sleep(int nSecond) Ib/e\+H\  
{ mv$gL  
try{ Fy6Lz.baB  
Thread.sleep(nSecond); j/ARTaO1]"  
} -B7X;{  
catch(Exception e) R"F:(  
{ l u{6  
e.printStackTrace (); Q;m8 drU  
} &RHx8zScP  
} vr kj4Jf  
00Ye ]j_  
//日志 /kO%aN  
public static void log(String sMsg) ^p%3@)&  
{ ej(< Le\  
System.err.println(sMsg); mD?={*7%  
} o6:]Hvqjr  
w(y 9y9r]  
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public static void log(int sMsg) fLkC

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{ m^tf=O<  
System.err.println(sMsg); 99~-TiU  
} u*7>0o|H:  
} 7Mh!@Rd_V  
]<_v;Q<t  
`Q>qmf_Fi  
/* wu}Z
u  
**TestMethod.java k/Ao?R=@gI  
*/ S09Xe_q  
package NetFox; oPF n`8dQ  
@< 0c  
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public class TestMethod { ^|cax|
>  
^/$U(4  
=u5( zaBe  
public TestMethod() fQ2U|  
{ ///xx/weblogic60b2_win.exe CL!s #w1I\  
try{ R\u5!M$::  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qcBamf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L^ U.h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z{U^j:A
 
fileFetch.start(); 1#vi]CX  
} ;xu&%n[6@  
catch(Exception e){e.printStackTrace ();} u$(XZ;Jg  
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a#/~rNRY  
} d!4:nvKx  
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*
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public static void main(String[] args) Gmmh&Uj  
{ U~8, N[  
new TestMethod(); qoC<qn{.a  
}  ByjgM`
 
} rJCu6  
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