http断点续传简单实现（java)

/* Y1yXB).AH8  
**SiteFileFetch.java lNh=>DPu  
*/ ]*g ss'N  
package NetFox; A| gs Uh  
import java.io.*; !8  wid&  
import java.net.*; K{=r.W  
[I++>4  
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public class SiteFileFetch extends Thread { iO?gF  
c+E//X|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Y uw E 0  
long[] nStartPos; //开始位置 (}*\ {  
long[] nEndPos; //结束位置 F;?TR[4!k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (EOec5qXU  
long nFileLength; //文件长度 Lt;.Nw  
boolean bFirst = true; //是否第一次取文件 ~4=]%XYz  
boolean bStop = false; //停止标志 ,<;l"v(  
File tmpFile; //文件下载的临时信息 M5T=Fj86  
DataOutputStream output; //输出到文件的输出流 :\1rQT  
2\nB
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uGP[l`f|FQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException X|-v0 f  
{ (5Z8zNH`3  
siteInfoBean = bean; 8g# c%eZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mJGO)u&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V(lK`dY  
if(tmpFile.exists ()) GG@I!2,_  
{ gfdPx:7^  
bFirst = false; t3  uB  
read_nPos(); e-%7F]e  
} k lP{yxU'n  
else xI`Uk8-8  
{ |iwM9oO%  
nStartPos = new long[bean.getNSplitter()]; %S >xSqX  
nEndPos = new long[bean.getNSplitter()]; jlRl2 #"  
} ,yHzo  
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8
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} 7GBZA=J  
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public void run() d$"G1u~%  
{ jpYw#]Q  
//获得文件长度 B%%.@[o,  
//分割文件 <?>I\  
//实例FileSplitterFetch 3D?IG\3  
//启动FileSplitterFetch线程 :Bx+WW&P.i  
//等待子线程返回 dDv
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try{ O:`GL1{ve?  
if(bFirst) RQj`9F  
{ E(aX4^]g  
nFileLength = getFileSize(); ";-{~  
if(nFileLength == -1) */%$6s~  
{ $I)Tk`=  
System.err.println("File Length is not known!"); V!pq,!C$v  
} sW]yuu!/  
else if(nFileLength == -2) vF.?] u  
{ wE,=%?"  
System.err.println("File is not access!"); I<D&,LFH*w  
} 2cs?("8e%  
else aJK-O"0/  
{ c{'$=lR "  
for(int i=0;i<nStartPos.length;i++) ys&"r":I  
{ g^
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ht`<XbQ>  
} 7.7Cluh5,  
for(int i=0;i<nEndPos.length-1;i++) '|YtNhWZ?  
{ ILkjz^  
nEndPos = nStartPos[i+1]; } D/+<  
} ')AByD}Hi]  
nEndPos[nEndPos.length-1] = nFileLength; _%A/ )  
} D:YN_J"kV  
} l1-4n*fU  
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$:%*gY4~76  
//启动子线程 5z9r S<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T!m42EvIvE  
for(int i=0;i<nStartPos.length;i++) $\0cJCQ3  
{ |Q5H9<*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D 7Gd
%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f0-RhR  
nStartPos,nEndPos,i); $Qn&jI38  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9O),/SH;:  
fileSplitterFetch.start(); g>6:CG"  
} HO266M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 89*S?C1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bh=
\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J>f /u:.  
nEndPos = " + nFileLength); 3q'K5} _  
// fileSplitterFetch[nPos.length-1].start(); +O|_P`HBoI  
]}nu9z<  
v t^r1j  
//等待子线程结束 tpv?`(DDU  
//int count = 0; QT`fix{  
//是否结束while循环 _Ct}%-,4  
boolean breakWhile = false; Y;fuh[#  
C#A@)>  
&E.OyqGZV  
while(!bStop) `y1BTe&  
{ umJay
/>  
write_nPos(); +V2C}NQ5R  
Utility.sleep(500); 5T!&r  
breakWhile = true; Nawp t%  
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for(int i=0;i<nStartPos.length;i++) bZxv/\
  
{ 5/Ydv RB67  
if(!fileSplitterFetch.bDownOver) * zd.  
{ {&u Rd?(  
breakWhile = false; u=(H#o<#  
break; WEno+Z~=1'  
} ; qO@A1Hq  
} n(Qj||:  
if(breakWhile) jIKBgsiF/  
break; w+Ad$4Pf
"  
Us1@\|]  
x2Ha&  
//count++; ]a8eDy  
//if(count>4) 4;?1Kb#  
// siteStop(); 1oB$MQoc  
} ym
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System.err.println("文件下载结束！"); ZQ@3P7T  
} 7TP$  
catch(Exception e){e.printStackTrace ();} A3xbT\xdg  
} [`q.A`Fd  
Gj6<s./  
Lt>?y&CcQ  
//获得文件长度 "K8nxnq  
public long getFileSize() P<8LAc$T  
{ yxqTm%?y  
int nFileLength = -1; HS7R lU^  
try{ MY&<)|v\  
URL url = new URL(siteInfoBean.getSSiteURL()); TV<Aj"xw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pH^ z  
httpConnection.setRequestProperty("User-Agent","NetFox"); c qv.dC  
L%f
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int responseCode=httpConnection.getResponseCode(); y*_K=}pk  
if(responseCode>=400) %?@x]B9Y8E  
{ =1O?jrl~q  
processErrorCode(responseCode); AD(xaQ&T  
return -2; //-2 represent access is error O)l%OOv   
} l+oDq'[q"  
)#C_mB$-#  
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String sHeader; 61
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-H4PRCDH  
{d8^@UL  
for(int i=1;;i++) k@
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{ !!9{U%s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); miPmpu!  
//Utility.log(in.readLine()); 8`a,D5U:  
sHeader=httpConnection.getHeaderFieldKey(i); YRXK@'[=  
if(sHeader!=null) L+Eu d  
{ AYt*'Zeg!s  
if(sHeader.equals("Content-Length")) #0(fOHPQ  
{ :sFo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &
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break; 0"4J"q]&  
} 5H~@^!7t  
} >;m{{nj  
else (:JjQ`i  
break; )q^(T1  
} 0Qt~K#mr/  
} R!9qQn?  
catch(IOException e){e.printStackTrace ();} 3zbXAR*  
catch(Exception e){e.printStackTrace ();} v C^>p5F  
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Utility.log(nFileLength); jBS'g{y-!  
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return nFileLength; Bf/|{@  
} Rw/Ciw2@?  
nVNs][  
_$!`VA%  
//保存下载信息（文件指针位置） pVY4q0@  
private void write_nPos() SGQDro=l  
{ Jlz9E|*qV  
try{ <W?WUF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7O"hiDQ  
output.writeInt(nStartPos.length); ("b*? : B  
for(int i=0;i<nStartPos.length;i++) _OLI%o  
{ yk`)
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// output.writeLong(nPos); s_TD4~ $  
output.writeLong(fileSplitterFetch.nStartPos); XYMxG:  
output.writeLong(fileSplitterFetch.nEndPos); FQ1arUOFW,  
} C]M7GHe1q  
output.close(); &"xQ~05  
} SijS5irfk  
catch(IOException e){e.printStackTrace ();} $ND90my  
catch(Exception e){e.printStackTrace ();} |g+!
  
} <;aJ#qT  
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//读取保存的下载信息（文件指针位置） .izf#r:<  
private void read_nPos() b22LT52  
{ pcNSL'u+  
try{ db'K!M)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y>)MAzz~\  
int nCount = input.readInt(); eJW[ ]!  
nStartPos = new long[nCount]; }{A?PHV5  
nEndPos = new long[nCount]; j"i#R1T  
for(int i=0;i<nStartPos.length;i++) ?@>;/@  
{ *CzCUu:%t  
nStartPos = input.readLong(); zx7#)*  
nEndPos = input.readLong(); xvdY 8%S  
} 8sH50jeP  
input.close(); BO]=vH  
} *
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:  
catch(IOException e){e.printStackTrace ();} l!/!?^8|f  
catch(Exception e){e.printStackTrace ();} (m/aV  
} 4 ]sCr+
 
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private void processErrorCode(int nErrorCode) svqvG7  
{ Vli3>K&  
System.err.println("Error Code : " + nErrorCode); k},>^qE  
} lYP~3wp99  
I.-v?1>,  
!:dL~n  
//停止文件下载 !
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public void siteStop() $M39 #a  
{ :,47rN,qa  
bStop = true; Hk~k@Wft  
for(int i=0;i<nStartPos.length;i++) aTG[=)xL  
fileSplitterFetch.splitterStop(); _=?2 3
 
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]
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} V8tghw  
} EDtCNqBS~2  
//负责部分文件的抓取 viJJ e'\2  
**FileSplitterFetch.java z(rK^RT  
*/ h07eEg  
package NetFox; l^
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import java.io.*; .$P|^Zx,  
import java.net.*; b[yE~EQxr  
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public class FileSplitterFetch extends Thread { l=xt;c!  
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String sURL; //File URL :PUK6,"5]O  
long nStartPos; //File Snippet Start Position 6e<^oH  
long nEndPos; //File Snippet End Position Gnk|^i;t  
int nThreadID; //Thread's ID Co[n--@C  
boolean bDownOver = false; //Downing is over Tt%}4{"  
boolean bStop = false; //Stop identical -,|ha>r  
FileAccessI fileAccessI = null; //File Access interface -Uri|^t  
7=vYO|a/4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Qm; BUG]  
{ 7OE[RX8!f  
this.sURL = sURL; wA631kr  
this.nStartPos = nStart; SOs,)  
this.nEndPos = nEnd; rd">JEK;
;  
nThreadID = id; /K@$#x_{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .yX>.>"T|  
} |AC6sfA+  
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public void run() &wb9_?ir-  
{ !)nD xM`p  
while(nStartPos < nEndPos && !bStop) [Y$V\h=V  
{ d
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aHC%19UN  
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try{ f1J%]g!  
URL url = new URL(sURL); r6MB"4xd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <6R"h-u"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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String sProperty = "bytes="+nStartPos+"-"; GG+5/hU  
httpConnection.setRequestProperty("RANGE",sProperty); xDUaHE1co  
Utility.log(sProperty); P5Dk63z]  
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InputStream input = httpConnection.getInputStream(); 79wLT\&  
//logResponseHead(httpConnection); _ eiF@G  
8%-%AWF]  
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byte[] b = new byte[1024]; lLMPw}r<  
int nRead; #%8 w
  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ nP;;MX:B  
nStartPos += fileAccessI.write(b,0,nRead); "wINBya'M  
//if(nThreadID == 1) L+t[&1cW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S>#R_H<(  
} k}U JVH21k  
`kPc!I7Y  
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Utility.log("Thread " + nThreadID + " is over!"); YZ**;"<G  
bDownOver = true; :u-.T.zZl  
//nPos = fileAccessI.write (b,0,nRead); ) $#(ZL^m  
} N Bz%(?\  
catch(Exception e){e.printStackTrace ();} cix36MR_  
} f
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} (u9Zk~)F  
:XYy7xz<  
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//打印回应的头信息 B9^R8|V  
public void logResponseHead(HttpURLConnection con) jA<T p}$!  
{ CV3DMA  
for(int i=1;;i++) lhxdx   
{ S(w\ZC  
String header=con.getHeaderFieldKey(i); !W~<q{VTs  
if(header!=null) sOz sY7z3Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I7zn>^0}  
Utility.log(header+" : "+con.getHeaderField(header)); JiA'BEJN  
else 3e 73l  
break; uy9!qk  
} ]Uh1l.O  
} ="dDA/,$VS  
!^L-T?y.2  
8&."uEOOU  
public void splitterStop() Dft%ip2  
{ uw"*zBxl  
bStop = true; k!owl+a   
} Ia7D F'  
c{4R*|^  
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} u(2BQO7  
]7vf#1i<  
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/* ?(D}5`Nfu  
**FileAccess.java agT7=hX].  
*//文件访问(定位，写) SQE` U  
package NetFox; N"1QX6  
import java.io.*; W_}/O'l{  
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public class FileAccessI implements Serializable{ ]! )xr  
"i%jQL'.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LS6ry,D"7  
RandomAccessFile oSavedFile;
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long nPos; d.cCbr:  
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public FileAccessI() throws IOException |^iA6)Q  
{ y\z > /q  
this("",0); 6#|qg*OS  
} >qpqQ; bm  
8Zw]f-5x\  
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public FileAccessI(String sName,long nPos) throws IOException Ay%:@j(E  
{ wv^b_DR  
oSavedFile = new RandomAccessFile(sName,"rw"); (Oq
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this.nPos = nPos; 4swKjN &  
oSavedFile.seek(nPos); afUTAP@  
} (Fqa][0  
}# Xi`<{  
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public synchronized int write(byte[] b,int nStart,int nLen) b{pg!/N4  
{ Hg whe=P  
int n = -1; jb3.W  
try{ Spo+@G  
oSavedFile.write(b,nStart,nLen); L|J~9FM  
n = nLen; 9wMEvX70  
} EneAX&SG  
catch(IOException e) q,@+^aZ  
{ @\PpA9ebg%  
e.printStackTrace (); )Mi'(C;  
} ` FxtLG,F  
U`1l8'W}:#  
4+Ti7p06&\  
return n; blp=Hk  
} VVLIeJ(*XT  
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} ?K<ZkYw?  
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fYn{QS?  
/* QS;F+cmTh  
**SiteInfoBean.java B{PLIis
c  
*/ :~33U)?{T  
package NetFox;  f`J|>Vk  
g}r^Xzd;  
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public class SiteInfoBean { +6376$dC  
@/(@/*+"  
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private String sSiteURL; //Site's URL
$iHoOYx]<  
private String sFilePath; //Saved File's Path ZqP7@fO_%  
private String sFileName; //Saved File's Name \xeVDKJH+n  
private int nSplitter; //Count of Splited Downloading File k/bque  
6w!e?B2/%  
L=m:/qQL  
public SiteInfoBean() a2X h>{  
{//nSplitter的缺省值为5 ]#5^&w)'  
//default value of nSplitter is 5 5[<F_"x  
this("","","",5); OpqNEo\  
} N8 M'0i?  
*%?d\8d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Mciq-c)  
{ Y}/c N\  
sSiteURL= sURL; gVA; `<  
sFilePath = sPath; =)*JbwQ   
sFileName = sName; .+vd6Uc5a  
this.nSplitter = nSpiltter; ]>vf9]  
6ZOAmH fs  
T<M?PlED  
} 9gR.RwR X  
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public String getSSiteURL() A
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{ 
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return sSiteURL; n$ dw<y  
} 7V'Le2T'  
zp
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B.6`cM^  
public void setSSiteURL(String value) h~fWE  
{ @?d?e+B  
sSiteURL = value; x;mJvfX  
} _NT[ ~M_Q  
~lk@6{`l|1  
48k7/w\  
public String getSFilePath()
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{ pw;r 25   
return sFilePath; f8#*mQ  
} $`v+4]  
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public void setSFilePath(String value) y7La_FPrl  
{ t\|J&4!Y  
sFilePath = value; uOFnCy 4  
} ArL-rJ{}  
*`1bc'umM;  
9t}J|09i  
public String getSFileName() A!4VjE>  
{ *;P2+cE>H3  
return sFileName; /.2qWQH  
} 9fMSAB+c%  
.?Auh2nr  
.<dOED{v  
public void setSFileName(String value) /sV?JV[t  
{ @`Wt4<  
sFileName = value; 6W:1>,xS  
} #!L%J<MX  
Q ]0r:i= .  
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public int getNSplitter() eK*W=c#@  
{ kXMP=j8  
return nSplitter; B5 &YL  
} Br&^09S  
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sxk*$jO[]  
public void setNSplitter(int nCount) uR
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{ ;le0QA Pf  
nSplitter = nCount; c(E,&{+E  
} /:KQAM0  
} @ge LW!  
]/[0O+B?  
{!y<<u1  
/* Tm\OYYyk  
**Utility.java "]UIz_^'`U  
*/ ?^F5(B[+Y  
package NetFox; AygvJeM_W  
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public class Utility { VAg68EbnF  
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public Utility() V $>"f(  
{ ]Ly8s#<g]N  
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} %b9fW  
A'`P2Am  
//线程睡眠 &8afl"_~  
public static void sleep(int nSecond) s_v}=C^  
{ Oi
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try{ RJL
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Thread.sleep(nSecond); A-;^~I  
} ^F&A6{9f/h  
catch(Exception e) 3@'lIV ?,q  
{ ve~C`2=;  
e.printStackTrace (); 8lpzSJP4k  
}  qJURPK  
} ^H-QYuz:T0  
Qj:{p5H'  
//日志 .X^43 q  
public static void log(String sMsg) ]Cr]Pvab{  
{ %pqL-G  
System.err.println(sMsg); /xJY7yF  
} pKnIQa[c  
l:x_j\  
| 4 `.#4  
public static void log(int sMsg) g/!Otgfu  
{ UFL0K  
System.err.println(sMsg); c<>y!^g  
} ~n8F7  
} VD9J
}bgJ  
cT I,1U  
/XN*)m  
/* n-W?Z'H{r  
**TestMethod.java [{?;c+[  
*/ 4V1|jy3  
package NetFox; K: 4P;ApI  
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public class TestMethod { ;}f6Y['z  
jKYm/}d  
kv/(rKLp*  
public TestMethod() 0T=jR{j!o  
{ ///xx/weblogic60b2_win.exe uV!MW=
)  
try{ O4n8MM|`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C5cFw/',  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ')rD?Z9 ^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b6]e4DL:R  
fileFetch.start(); )S#j.8P'B  
} coSTZ&0  
catch(Exception e){e.printStackTrace ();} (5>{?dR)|  
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} A xRl*B  
sBbL~ce50?  
FDl,Ey^r/  
public static void main(String[] args) A7.JFf>  
{ f x%z|K  
new TestMethod(); EmF]W+!z%  
} FW/)uf3I  
} {rs6"X^  
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