http断点续传简单实现（java)

/* UNY O P{  
**SiteFileFetch.java L6<.>\^Z"  
*/ }w&W\g+E$  
package NetFox; w=JO$7  
import java.io.*; icS%])3LF  
import java.net.*; ?V&#nA  
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V7DMn@Ckw  
public class SiteFileFetch extends Thread { =[5F~--Tf  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q#D-}R_RN  
long[] nStartPos; //开始位置 BRSIg]  
long[] nEndPos; //结束位置 inQ1$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {+Zj}3o  
long nFileLength; //文件长度 ]"q9~  
boolean bFirst = true; //是否第一次取文件 V?t56n Y}  
boolean bStop = false; //停止标志 i=3~ h Zl  
File tmpFile; //文件下载的临时信息 c6-~PKJL  
DataOutputStream output; //输出到文件的输出流 9 n0?0mk  
?$$Xg3w_#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -,:^dxE'  
public SiteFileFetch(SiteInfoBean bean) throws IOException }ZqnsLu[)  
{ b,h@.s  
siteInfoBean = bean; }jdMo83  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @qUgp
*+{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +-2W{lX  
if(tmpFile.exists ()) '<=77yDg  
{ )>"|<h.2]  
bFirst = false; tW-wO[2  
read_nPos(); -8zdkm8k  
} tEuVn5  
else uE &/:+  
{ Y' FB {  
nStartPos = new long[bean.getNSplitter()]; zy'e|92aO  
nEndPos = new long[bean.getNSplitter()]; E5iNuJj=f  
} -sqd?L.p  
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} @js`$  
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public void run() zQ~N(Jj?h  
{ _~Id~b  
//获得文件长度 GHWt3K:*w  
//分割文件 mE"(d*fe'  
//实例FileSplitterFetch :@@aIFRv  
//启动FileSplitterFetch线程 *q-VY[2  
//等待子线程返回 (l+0*o,(  
try{ D]=V6l=  
if(bFirst) b9R0"w!ml  
{ 3D}Pa  
nFileLength = getFileSize(); w<LV5w+  
if(nFileLength == -1) h~pQ  
{ FFtB#  
System.err.println("File Length is not known!"); ZHM NG~!  
} )k[{re  
else if(nFileLength == -2) Xl,707  
{ %`bn=~T^  
System.err.println("File is not access!"); \RS0mb  
} )tm%0z7R  
else O$ARk+  
{ }vxRjO,  
for(int i=0;i<nStartPos.length;i++) gySl.cxt  
{ @rP#ktz]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f = 'AI  
} Z'~/=a)7  
for(int i=0;i<nEndPos.length-1;i++) V}h <,E9  
{ \_)[FC@  
nEndPos = nStartPos[i+1]; M{t/B-'4  
} XUVBD;"f!  
nEndPos[nEndPos.length-1] = nFileLength; v%muno,  
}  CH$K_\  
} gq~K(Q<O<  
b5)1\ANq  
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//启动子线程 1\aV
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K BlJJH`z{  
for(int i=0;i<nStartPos.length;i++) /$d#9Uv  
{ PDpuHHB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GYrUB59  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ly`\TnC  
nStartPos,nEndPos,i); cTja<*W^xv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KFBBqP  
fileSplitterFetch.start(); *X!+wK-+  
} Gvl,M\c9-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4axuE]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t>vr3)W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G0u H6x?  
nEndPos = " + nFileLength); *|OUd7P:hU  
// fileSplitterFetch[nPos.length-1].start(); Bs
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*+%$OH,  
|RH^|2:x9Q  
//等待子线程结束 ,f~)CXNT?  
//int count = 0; kl|m @Nxp
 
//是否结束while循环 KwY6pF*  
boolean breakWhile = false; 8/@*6J  
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6{  
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while(!bStop) *XI- nH  
{ iU|X/>k?  
write_nPos(); x<5;#  
Utility.sleep(500); 4D[(X=FSU  
breakWhile = true;  c`}YL4  
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4}t$Lf_  
for(int i=0;i<nStartPos.length;i++) 79 \SbB  
{ ]P2Wa   
if(!fileSplitterFetch.bDownOver) F8J\#PW  
{ [+!~RV_  
breakWhile = false; !jg< S>S5  
break; -n:;/ere7-  
} g*WY kv  
} *|
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if(breakWhile) lQL/I[}  
break; B$G9#G6pZ  
4|hfzCjMI  
7g4IAsoD  
//count++; ?NxaJ^  
//if(count>4) |[@v+koq  
// siteStop(); 0?''v>%  
} >CYz6G j  
**]=!W  
_4LDzVjNRe  
System.err.println("文件下载结束！"); ?]\v%[ho  
} v<atic  
catch(Exception e){e.printStackTrace ();} nFjaV`6`@  
} 2UMX%+ "J  
>&JS-jFg  
^V"
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//获得文件长度 2E.D0E Cu  
public long getFileSize() r@CbhD  
{ qhmA)AWG>  
int nFileLength = -1; #TI
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try{ s,j=Kym%  
URL url = new URL(siteInfoBean.getSSiteURL()); L-|u=c-6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E8.1jCL>{"  
httpConnection.setRequestProperty("User-Agent","NetFox"); o;v
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-+Z&O?pSH  
EdCcnl?R6  
int responseCode=httpConnection.getResponseCode(); SpMHq_MLM  
if(responseCode>=400) (/|f6_9!  
{ *X2dS {  
processErrorCode(responseCode); RaA7 U   
return -2; //-2 represent access is error H284 ]i  
} AQs_(L
R  
]eI|_O^u  
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String sHeader; |iVw7M:  
+L pMNnl6  
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for(int i=1;;i++) 5r^u7k  
{ 2SYV2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nC\LDeKc  
//Utility.log(in.readLine()); N#^o,/  
sHeader=httpConnection.getHeaderFieldKey(i); 1ifPc5j}  
if(sHeader!=null)  ?d
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{ S^)xioKsJ  
if(sHeader.equals("Content-Length")) \; zix(N[5  
{ %`j2?rn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N lB%Qu  
break; b|U3\Fmc  
} b(_PV#@$  
} 5xc-MkIRL  
else `IK3e9QpcA  
break; eSSv8[u  
} 0*:4@go0}i  
} XtIY8wsP  
catch(IOException e){e.printStackTrace ();} ^oZD44$  
catch(Exception e){e.printStackTrace ();} KCfcEz  
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 gX]'RBTb  
Utility.log(nFileLength); Lu~M=Fh  
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return nFileLength; 7;NvR4P%  
} (L"G,l  
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xcN >L  
//保存下载信息（文件指针位置） ]dHV^!  
private void write_nPos() WC 5v#*Jd  
{ y_Nn%(j  
try{ $c24lJ#/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3qq6X?y*  
output.writeInt(nStartPos.length); d<v)ovQJ]  
for(int i=0;i<nStartPos.length;i++) oB
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{ d+g+{p>?  
// output.writeLong(nPos); _"sFLe{  
output.writeLong(fileSplitterFetch.nStartPos); !,N),xG}~  
output.writeLong(fileSplitterFetch.nEndPos); si|b>R&Z  
} cz$q~)I$  
output.close(); Sv03="&  
} }'Yk#Q  
catch(IOException e){e.printStackTrace ();} N,u~ZEI  
catch(Exception e){e.printStackTrace ();} f"A?\w@  
} ,7izrf8  
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//读取保存的下载信息（文件指针位置） ]}jY] l  
private void read_nPos() fAV=O%^  
{ T\o!^|8
 
try{ YGr^uTQb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uM9RlI5  
int nCount = input.readInt(); /,2${$c!  
nStartPos = new long[nCount]; {;ur~KE  
nEndPos = new long[nCount]; ;PhX[y^*  
for(int i=0;i<nStartPos.length;i++) L51uC ,QF  
{ }&Jml%F4uR  
nStartPos = input.readLong(); `K\(I#z  
nEndPos = input.readLong(); H He~OxWg  
} oj~0zJI  
input.close(); Y7 `i~K;  
} 9oJ=:E~CP  
catch(IOException e){e.printStackTrace ();} U/bQ(,3
}  
catch(Exception e){e.printStackTrace ();} _sp/RU,J-3  
} s1NRUV2E  
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private void processErrorCode(int nErrorCode) gDjs:]/YR  
{ cakb.Q  
System.err.println("Error Code : " + nErrorCode); ,-{2ai_  
} $@:z4S(  
7nL3+Pq  
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//停止文件下载 /=2  
public void siteStop() Qd$!?h  
{ j{u!/FD  
bStop = true; rocG;$[  
for(int i=0;i<nStartPos.length;i++) :$>TeCm  
fileSplitterFetch.splitterStop(); Rw\S-z/  
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} 2u|}gZts  
} GwaU7[6  
//负责部分文件的抓取 y!?l;xMS  
**FileSplitterFetch.java DEkFmmw   
*/ pn6!QpV5  
package NetFox; ~wsDg[  
P2;I0 !  
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import java.io.*; *PJg~F%  
import java.net.*; 4#BoS9d2I<  
'Nbae-pf  
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public class FileSplitterFetch extends Thread { ;n,@[v  
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String sURL; //File URL p
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long nStartPos; //File Snippet Start Position "' hc)58y  
long nEndPos; //File Snippet End Position |_J[n!~f7  
int nThreadID; //Thread's ID idr,s\$>  
boolean bDownOver = false; //Downing is over `Vqpo/  
boolean bStop = false; //Stop identical @fWmz,Ngl  
FileAccessI fileAccessI = null; //File Access interface DdL0MGwX  
RjS&^uaP  
n(#159pZ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -S"$S16D  
{ N{<=s]I%x  
this.sURL = sURL; s]
=s|  
this.nStartPos = nStart; ;h"?h*}m!\  
this.nEndPos = nEnd; ,HFoy-Yq  
nThreadID = id; duKR;5:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 YkKq}DXj  
} <([1(SY2e  
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public void run() RqIic\aD  
{ /f7Fv*z/  
while(nStartPos < nEndPos && !bStop) .Qp5wCkM  
{ %:eepG|  
|*im$[g=-  
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try{ FN&.PdRT  
URL url = new URL(sURL); Q4_+3-g<7L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0 pHqNlb  
httpConnection.setRequestProperty("User-Agent","NetFox"); 12
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String sProperty = "bytes="+nStartPos+"-"; q
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httpConnection.setRequestProperty("RANGE",sProperty); z6K"}C%  
Utility.log(sProperty); qdB@P  
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InputStream input = httpConnection.getInputStream(); MT,LO<.  
//logResponseHead(httpConnection); /2&jId  
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byte[] b = new byte[1024]; s wdW70  
int nRead; ,?+rM ;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "mnWqRpX  
{ F(8>"(C  
nStartPos += fileAccessI.write(b,0,nRead); mACj>0Z'  
//if(nThreadID == 1) Y)>GwFK$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Q`GA<ikv  
} J>P{8Aw  
n:GK0wu.s  
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Utility.log("Thread " + nThreadID + " is over!"); PF-7AIxs"  
bDownOver = true; 4425,AR  
//nPos = fileAccessI.write (b,0,nRead); i51
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} &P%3'c}G  
catch(Exception e){e.printStackTrace ();} vv  _I o  
} 1FS Jqa
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} \k1psqw^O  
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//打印回应的头信息 H[guJ)4#@  
public void logResponseHead(HttpURLConnection con) i6zfr|`@  
{ )g:\N8AZK  
for(int i=1;;i++) ;$G.?r  
{ 9}FWO&LiB  
String header=con.getHeaderFieldKey(i); 3y%B&W,sm  
if(header!=null) c,1Yxg]|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?Ovl(4VG  
Utility.log(header+" : "+con.getHeaderField(header)); cbl2D5s+i]  
else 1pC!F ;9Oo  
break; FrO)31z  
} Vt:]D?\3  
} e g#.f`  
u0^: XwZ!  
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public void splitterStop() &,xN$  
{ u{'bd;.7  
bStop = true; 5tg  
} 1O1/P,u+  
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"z\T$/  
} }+0{opY4R  
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cs7TAX  
/* 7z"xjA  
**FileAccess.java {T Z7>k  
*//文件访问(定位，写) V+X>t7.Q  
package NetFox; 2JZf@x+}  
import java.io.*; ;}{%|UAsx  
V?v,q'? $  
}\`MXh's
 
public class FileAccessI implements Serializable{ w} *;^n  
P=eVp(/x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p6]4YGw*^  
RandomAccessFile oSavedFile; :04sB]H  
long nPos;  4G&E?  
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public FileAccessI() throws IOException A1:<-TF6^p  
{ , gk49z9  
this("",0); 7_taqcj  
} QF(.fq8, U  
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public FileAccessI(String sName,long nPos) throws IOException 3hr&p{/  
{ {%xwoMVc+  
oSavedFile = new RandomAccessFile(sName,"rw"); _e$15qW+  
this.nPos = nPos; A^_BK(EY  
oSavedFile.seek(nPos); Mf%0Cx `  
} ^!-*xH.dK  
.oYUA}  
Fd-PjW/E8  
public synchronized int write(byte[] b,int nStart,int nLen) v2:A 4Pd:+  
{ zR(}X8fP  
int n = -1; (7q!Z!2  
try{ ;wIpche  
oSavedFile.write(b,nStart,nLen); y]aV7 `]  
n = nLen; q-gN0"z^6$  
} bR6.Xdt.n  
catch(IOException e) @Hj5ZJ 3  
{ 1+RG@
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e.printStackTrace (); LY[XPV]t  
} 7.$0LN/a!Z  
pw*<tXH!  
V} Y %9V  
return n; 7y:%^sl  
} [f}YXQ0N)  
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} VS<E?JnbFV  
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/* 6wx;grt'Z  
**SiteInfoBean.java *|ez|*-  
*/ ~;k-/Z"  
package NetFox; m'k.R j  
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public class SiteInfoBean { @dQIl#  
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private String sSiteURL; //Site's URL XtVx H4q  
private String sFilePath; //Saved File's Path l=U@j T  
private String sFileName; //Saved File's Name Enn7p9&  
private int nSplitter; //Count of Splited Downloading File IlJ6&9  
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= ;#?CAa:  
public SiteInfoBean() DVt;I$  
{//nSplitter的缺省值为5 An!1>`8r  
//default value of nSplitter is 5 2Jl6Xc8  
this("","","",5); J`a$"G B.  
} Aa-L<wZVPt  
fOCLN$x^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yB\}e'J^  
{ MW8GM}Ho[  
sSiteURL= sURL; H=[eO  
sFilePath = sPath; #
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sFileName = sName; >&3M #s(w  
this.nSplitter = nSpiltter; T1jAY^^I  
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} Yo3my>N&g  
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public String getSSiteURL() 4;'o`K~*  
{ <QFT>#@T  
return sSiteURL; }.ZX.qYX  
} &2[OH}4  
}#5Vt  
.
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public void setSSiteURL(String value) 9`Bmop  
{ nI.K|hU:P  
sSiteURL = value; ;QkUW<(  
} "n3r,  
HpY-7QTPJ~  
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public String getSFilePath() ^.)oQo SE  
{ F8mS5oB|^  
return sFilePath; p;cNmMm  
} /MYl:>e>  
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public void setSFilePath(String value) >Q#h,x~vu  
{ T#kPn#|  
sFilePath = value; 0w9)#e+JS  
} TELN4*  
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public String getSFileName() p&dpDJ?d:=  
{ VWf&F`^B(  
return sFileName; 9`  
} NQ~keN  
5e=9~].7  
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public void setSFileName(String value) 7pf]h$2  
{ /W\@
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sFileName = value; 4FUY1p  
} }-QFMPXhG  
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public int getNSplitter() jez=q  
{ mh&wvT<:{  
return nSplitter; 6BK-(>c(6  
} 8AL`<8$  
/vC|_G|{  
=y+gS%o$  
public void setNSplitter(int nCount) sI\v}$(~  
{ OZ>w.$ue  
nSplitter = nCount; _wMxKM  
} e>z  
} B!{vSBq  
,9;RP/"7  
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/* E;m]RtvH  
**Utility.java VRden>vKN  
*/ CqK&J /8  
package NetFox; Kz>bfq7  
0?c2=Y  
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public class Utility {  *-Y`7=^$  
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public Utility() \%&BK.t  
{
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} A#NJ8_  
_mSDz=!Z3  
//线程睡眠 n!Hj4~T0  
public static void sleep(int nSecond) M~'4>h}  
{ s4V-brCM$|  
try{ yC#%fgQ r  
Thread.sleep(nSecond); _yx~t  
} o>4mkh[3  
catch(Exception e) 0QJ :  
{ DpD19)ouy  
e.printStackTrace (); RHO|g0  
} |T`ZK?B+u  
} c,@&Z#IZ`  
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//日志 YA+jLy6ZL  
public static void log(String sMsg) 9ZXkuP9vm  
{ arVu`pD*n  
System.err.println(sMsg); ki|KtKAu_9  
}
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f6/<lSoW  
public static void log(int sMsg) BQWhTS7  
{ yV"k:_O{  
System.err.println(sMsg); d `MTc  
} 8M6 Xd]{%  
} B'NtG84  
{"v~1W)  
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/* |ty?Ah,vb  
**TestMethod.java y~ 2C2'7  
*/ %_P[ C}4  
package NetFox; 8U8%XIEJ  
E5;6ks)  
mYUR(*[  
public class TestMethod { ]u5B]ZQnA  
1`sLbPW  
gWk?g^KJL  
public TestMethod() 0Y>5&  
{ ///xx/weblogic60b2_win.exe pseN!7+or  
try{ bm>N~DC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {UeS_O>(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lIhP\:;S&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g49G7sk  
fileFetch.start(); !l6Ez_'  
} P^3`znq{  
catch(Exception e){e.printStackTrace ();} 9-/u _$  
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|lDxk
[  
} b#%$
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-s3q(SH  
&u`]Zn  
public static void main(String[] args) $.+_f,tU  
{ kuq&8f~!  
new TestMethod(); 42oW]b%P{;  
} B}(r>8?dm  
} ~:JoKm`vU  
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