http断点续传简单实现（java)

/* 2aUE<@RU[  
**SiteFileFetch.java OZ<fQf.Gh}  
*/ QT(]S>--n  
package NetFox; !]z4'*)W  
import java.io.*; Fj&8wZ)v)  
import java.net.*; [bBPs&7u  
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public class SiteFileFetch extends Thread { `cRRdD:dA  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &?9~e>.OS  
long[] nStartPos; //开始位置 BGO pUy  
long[] nEndPos; //结束位置 Gs*X> D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "@jYZm8  
long nFileLength; //文件长度 ~yRKNH*M  
boolean bFirst = true; //是否第一次取文件 _G^4KwYp  
boolean bStop = false; //停止标志 TSRl@QVy  
File tmpFile; //文件下载的临时信息 RAxp2uif  
DataOutputStream output; //输出到文件的输出流 CL!s #w1I\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） reNUIDt/c  
public SiteFileFetch(SiteInfoBean bean) throws IOException z&.F YGq}  
{ 7wbpQ&1_  
siteInfoBean = bean; aSfAu!j)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Nqbm,s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #BI Z|  
if(tmpFile.exists ()) >H]|R }h  
{ <7MxI@\  
bFirst = false; :*tFW~<*b  
read_nPos(); :l {%H^;1  
} <;!#+|L/  
else *i,A(f'e4X  
{ j3'SM#X  
nStartPos = new long[bean.getNSplitter()]; CEI.*Iywu  
nEndPos = new long[bean.getNSplitter()]; MeO2 cy!5q  
} Lhxg5cd  
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} ^^[A\'  
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public void run() !<0 `c  
{ ,GF(pCZzG  
//获得文件长度 )JR&  
//分割文件 =$< .:b  
//实例FileSplitterFetch }I~)o!N%7  
//启动FileSplitterFetch线程 R'B-$:u  
//等待子线程返回 $69d9g8-(!  
try{ p!`S]\XEB  
if(bFirst) D+4$l+\u  
{ |u^~Z-.  
nFileLength = getFileSize(); :LTjV"f  
if(nFileLength == -1) #nS crs@  
{ #8B4*gAM  
System.err.println("File Length is not known!"); +!-U+W  
} !<5Wi)*  
else if(nFileLength == -2) 4 :M}Vz-  
{ )H*BTfmt  
System.err.println("File is not access!"); G;^,T/q47  
} N9PEn[t@  
else ]l=iKl  
{ F%:o6mT  
for(int i=0;i<nStartPos.length;i++)
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{ ])Z p|?Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W!b'nRkq  
} |k/;1.b!9(  
for(int i=0;i<nEndPos.length-1;i++) -^$IjK-N  
{ <
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nEndPos = nStartPos[i+1]; \|R
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} k6|/ik9C  
nEndPos[nEndPos.length-1] = nFileLength; 7,R ~2ss5z  
} cg}lF9;d  
} zw%1a 3!  
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b}m@2DR'|m  
//启动子线程 VP6_}9:9   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -b'/}zz  
for(int i=0;i<nStartPos.length;i++) H:`H4S}  
{ ?H21Ru>:*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0@}:`OynX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F Xp_`9.zH  
nStartPos,nEndPos,i); idY Xv)R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zy^ wS1io  
fileSplitterFetch.start(); OCWyp  
} d'e\
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oSkvTK$&i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G8Zl[8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~4`
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nEndPos = " + nFileLength); bHioM{S  
// fileSplitterFetch[nPos.length-1].start(); RWXN  
C=P}@|K  
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//等待子线程结束 g,\O}jT\'  
//int count = 0; W,[iRmxn  
//是否结束while循环 6G>loNM^  
boolean breakWhile = false; I\$?'q>  
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while(!bStop) ;% l0Ml>  
{ _?;74VWA  
write_nPos(); fI-f Gx  
Utility.sleep(500); <
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breakWhile = true; C&RZdh,$  
pw=o
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for(int i=0;i<nStartPos.length;i++) o(oD8Ni  
{ Md>9Daa~  
if(!fileSplitterFetch.bDownOver) 4-W~1  
{ Ew&|!d  
breakWhile = false; @eN,m {b  
break; ~Da-|FKa>  
} QT[4\)  
} G$6mtw6[M  
if(breakWhile) kC/An@J^#  
break; RtF!(gd  
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//count++; } v3w-  
//if(count>4) F
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// siteStop(); w)"F=33}5  
} 6MelN^\[7  
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System.err.println("文件下载结束！"); w9CX5Fg  
} xgZ<.r  
catch(Exception e){e.printStackTrace ();} [lE^0_+  
} ]1|OQYG  
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9Q&]5|x  
//获得文件长度 6'jgjWEe3&  
public long getFileSize() %H=^U
8WB  
{ M8f[ck  
int nFileLength = -1; TZa LB}4  
try{ t7,**
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URL url = new URL(siteInfoBean.getSSiteURL()); k~=P0";  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _ IlRZ}
f  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9oj0X>| 1  
G PL^!_  
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int responseCode=httpConnection.getResponseCode(); !r9~K^EI
 
if(responseCode>=400) *!`bC@E  
{ y+$a}=c
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processErrorCode(responseCode); @4P_Yfn  
return -2; //-2 represent access is error +D M,+{}  
} !1`f84
d  
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String sHeader; {5JYu  
){4$oXQ  
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for(int i=1;;i++) c"NGE  
{ )wk9(|[o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \1#~]1~ s  
//Utility.log(in.readLine()); FES0lw{G#  
sHeader=httpConnection.getHeaderFieldKey(i); r-&* `Jh  
if(sHeader!=null) kjO
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{ xm> y3WC  
if(sHeader.equals("Content-Length")) E4xybVo@  
{ MG3xX;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); - *xn`DH  
break; VaTA|=[;  
} A2I\T,Z  
} pm:#@sl  
else +"PME1  
break; A1x   
} N7Kk
z /  
} NtQ#su$  
catch(IOException e){e.printStackTrace ();} /!W',9ua6  
catch(Exception e){e.printStackTrace ();} L}>ts(!q&  
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?7w7Y;FuR  
Utility.log(nFileLength); &8hW~G>(m  
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return nFileLength; 3+V.9TL'a  
} W(PNw2  
A
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-9$.&D|  
//保存下载信息（文件指针位置） *ub"!}$st  
private void write_nPos() c1g'l.XL 3  
{ 8!7`F.BX  
try{ Wfh+D[^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mxTuwx   
output.writeInt(nStartPos.length); >S:+&VN`M  
for(int i=0;i<nStartPos.length;i++) TR!7@Mu3  
{ RHuc#b0  
// output.writeLong(nPos); lt#3&@<v  
output.writeLong(fileSplitterFetch.nStartPos); cd)}a_9  
output.writeLong(fileSplitterFetch.nEndPos); ^PowL:  
} }*vO&J@z  
output.close(); g
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} i[Pk
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catch(IOException e){e.printStackTrace ();} 1"U.-I@  
catch(Exception e){e.printStackTrace ();} nT@FSt  
} q=+wQ[a<  
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M|qJZ#{4>  
//读取保存的下载信息（文件指针位置） Zu/1:8x  
private void read_nPos() >C}KSyV;  
{ ]!cLFXa  
try{ d>x(Bj6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T@Th?  
int nCount = input.readInt(); BU=Ta$#BZ  
nStartPos = new long[nCount]; qino:_g  
nEndPos = new long[nCount]; i^V3u  
for(int i=0;i<nStartPos.length;i++) IUQYoKz4}A  
{ 9HD5A$  
nStartPos = input.readLong(); #;<dtw  
nEndPos = input.readLong(); S5wkBdr{  
} ZnD(RM  
input.close(); i{k v$ir!  
} 1f0maN  
catch(IOException e){e.printStackTrace ();} XF9
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catch(Exception e){e.printStackTrace ();} UsdUMt!u  
} l"9$lF}
 
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private void processErrorCode(int nErrorCode) : W0;U  
{ [)nU?l  
System.err.println("Error Code : " + nErrorCode); 64f6D"."
 
} rqhRrG{L|&  
2yA+zJ 46B  
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//停止文件下载 N-}|!pqb  
public void siteStop() .<-~k@ P  
{ x$6FvgP(  
bStop = true; cDh\$7'b  
for(int i=0;i<nStartPos.length;i++) ` NWmwmWB"  
fileSplitterFetch.splitterStop(); H:X(><J  
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} /4,U@s)"/  
} n$ZxN"q <  
//负责部分文件的抓取 Xh`Oin}<  
**FileSplitterFetch.java :A`jRe.  
*/ =}[m_rp&  
package NetFox; l7uEUMV  
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n$3w=9EX*  
import java.io.*; 8PvO_Gz5  
import java.net.*; B[[1=  
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public class FileSplitterFetch extends Thread { j4Y] 8  
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String sURL; //File URL mH!\]fmR~  
long nStartPos; //File Snippet Start Position )|<g\>/  
long nEndPos; //File Snippet End Position 10$:^  
int nThreadID; //Thread's ID BHZSc(-o  
boolean bDownOver = false; //Downing is over I7jIA>ZZi  
boolean bStop = false; //Stop identical ^tl&FWF  
FileAccessI fileAccessI = null; //File Access interface 1:Xg&4s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A9M/n^61  
{ GlaZZ,   
this.sURL = sURL; #oEq)Vq>g|  
this.nStartPos = nStart; (eO_]<wmky  
this.nEndPos = nEnd; q4ej7T8  
nThreadID = id; H]>7IhJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e[t1V/ah  
} EtA,ow  
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public void run() $EPDa?$*  
{ /G#W/Q  
while(nStartPos < nEndPos && !bStop) rvBKJ!b0  
{ -(|}:J  
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+)*aS+  
try{ %)j^>W5  
URL url = new URL(sURL); dhI+_z   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mbZg2TTy  
httpConnection.setRequestProperty("User-Agent","NetFox"); f9J]-#Iif  
String sProperty = "bytes="+nStartPos+"-"; l[{Ci|4  
httpConnection.setRequestProperty("RANGE",sProperty); o)Nm5g  
Utility.log(sProperty); {aWfD XB1  
~Ec@hz]js  
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InputStream input = httpConnection.getInputStream(); Ui;PmwQc&  
//logResponseHead(httpConnection); ,\E5et4  
{;?bC'  
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byte[] b = new byte[1024]; 1Yy*G-7}  
int nRead; dF0:'y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Kw,l
n<)2  
{ }#9 |au`  
nStartPos += fileAccessI.write(b,0,nRead); `pYL/[5  
//if(nThreadID == 1) 3Tr}t.mt  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?=\_U  
} v$bR&bCT  
u
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Utility.log("Thread " + nThreadID + " is over!"); Fs1ms)  
bDownOver = true; Gm'Ch}E  
//nPos = fileAccessI.write (b,0,nRead); 9Q*zf@w  
} Pna2IB+  
catch(Exception e){e.printStackTrace ();} DqlspT  
} yy$7{9!  
} [:-o;K\.-a  
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//打印回应的头信息 LQ=Fck~[r  
public void logResponseHead(HttpURLConnection con) i+B
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{ -xc'P,`  
for(int i=1;;i++) Q4&<RWbT^  
{ ^W
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String header=con.getHeaderFieldKey(i); |Xa|%f  
if(header!=null) K6z-brvw"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b. oA}XP  
Utility.log(header+" : "+con.getHeaderField(header)); 9A1w5|X  
else O,!4 W\s  
break; 6'vt '9  
} 2[$` ]{U  
} <t4l5nr#  
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public void splitterStop() Ue]GHJ2  
{ f=*xdOB3  
bStop = true; h5R5FzY0&  
} H1g"09?h6o  
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} OgBZoTT  
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/* Z )dz  
**FileAccess.java ZVmgQ7m  
*//文件访问(定位，写) OQZ\/~o 5  
package NetFox; ](H vx  
import java.io.*; B%d2tsDw  
7U{g'<  
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public class FileAccessI implements Serializable{ Gn%gSH/  
[sH[bmLR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 JK9}Kb};  
RandomAccessFile oSavedFile; YKs^aQm#  
long nPos; :ift{XR'  
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public FileAccessI() throws IOException (~FLG I  
{ j(maj  
this("",0); +R?d6IjH  
} _K"X  
Dx<CO1%z-  
:X;AmLf`2u  
public FileAccessI(String sName,long nPos) throws IOException }];_ug* "  
{ ^04|tda  
oSavedFile = new RandomAccessFile(sName,"rw"); B?tO&$s  
this.nPos = nPos; )#l,RJ(  
oSavedFile.seek(nPos); >O&:[CgEF  
} y}bE'Od  
*T'>-nm]  
s8<)lO<SV.  
public synchronized int write(byte[] b,int nStart,int nLen) x=(cQmQ  
{ .\>I-  
int n = -1; e.IKmH]z  
try{ 8L7ZWw d  
oSavedFile.write(b,nStart,nLen); #7A_p8  
n = nLen; hup<U+p  
} zbDM+;  
catch(IOException e) ' Z}/3 dp  
{ Dj9).lgc  
e.printStackTrace (); q={\|j$X  
} ]}&f
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r%/*,lLO  
return n; H]7;OM/g  
} 3yfq*\_uXw  
a jCx"J  
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} c{u~=24;%#  
4F+n`{~  
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/* kt;| $  
**SiteInfoBean.java R)w|bpW  
*/ B^SD5  
package NetFox; ]7, mo  
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public class SiteInfoBean { p ft6 @'q  
|[VtYV _{  
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private String sSiteURL; //Site's URL bstc|8<  
private String sFilePath; //Saved File's Path 6h|@Bz/A  
private String sFileName; //Saved File's Name r%g?.4o*b  
private int nSplitter; //Count of Splited Downloading File +0Rr5^8u  
0/."R;  
;_lEu" -  
public SiteInfoBean() x_oL~~@  
{//nSplitter的缺省值为5 t4H@ZvAH0  
//default value of nSplitter is 5 0}UJP   
this("","","",5); {<HL}m@kQ  
} 6"Km E}  
_ s]=g  
0NB6S&lI^k  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lr[a~ca\  
{ btK| U  
sSiteURL= sURL; ;y7V-sf  
sFilePath = sPath; _Z|s!~wdz  
sFileName = sName; PL#
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this.nSplitter = nSpiltter; \1[I(u  
Xp=Y<`dX  
:A,V<Es}I"  
} (c<Krc h  
2@ >04]
 
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public String getSSiteURL() /]Fs3uf  
{ #cBt@SEL'  
return sSiteURL; -BNlZgk-^  
} QJ`#&QRp  
\:8eN}B  
9K@>{69WQ  
public void setSSiteURL(String value) FBM 73D@`  
{ T{={uzQeJJ  
sSiteURL = value; u":D{+wC|  
} Ey77]\  
g< cR/  
,*2%6t`N?  
public String getSFilePath() UlHRA[SCv  
{ zv]-(<B  
return sFilePath; iAX\F`  
} j w)Lofn  
dUtxG ~9  
YWSo:)LY  
public void setSFilePath(String value) pC
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{ "msCiqF{z  
sFilePath = value; x=yU }lsV  
} x-0IxWD%  
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public String getSFileName() aXyu%<@k  
{ EOrWax@k$}  
return sFileName; ~(tZW  
} K h9$  
:z^ps0  
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public void setSFileName(String value) 2,O-/A;tW*  
{ %Yg;s'F>#q  
sFileName = value; C|Bk'<MI  
} 2B_6un];W  
;^:9huN  
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public int getNSplitter() Jp.Sow  
{ />XfK,c-  
return nSplitter; Z&=K+P  
} BBw`8!  
L`YnrDZK  
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public void setNSplitter(int nCount) I]>-~_  
{ YH^_d3A;  
nSplitter = nCount; d3T|N\(DL  
} (|Am  
}
}$V]00 X  
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/* k0?4vA  
**Utility.java [UquI "  
*/ j3VM!/  
package NetFox; Q;{yIa$ $  
!o*BRR*  
6)P~3C'  
public class Utility { fcb:LPk;  
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@QtJ/("&WC  
public Utility() }1w[G;$  
{ A6}M F  
*Xt#04_  
Ly\$?3h  
} RMDs~  
m?xzx^xs/  
//线程睡眠 !,Wd$UK  
public static void sleep(int nSecond) 7|T<dfQk  
{ je.jui"  
try{ (`4^|_gw  
Thread.sleep(nSecond); -:m;ePK  
} kmM_Af&
 
catch(Exception e) +H_Jr'/  
{ 6}IOUWLB@  
e.printStackTrace (); 8iD_md_[  
} @y->4`N  
} q^Lj)zmnK  
9x&,`95O  
//日志 8nQlmWpJ  
public static void log(String sMsg) a9"x_IVU  
{ OnF+  
System.err.println(sMsg); @\Sa)  
} KU3lAjzN  
RX>kOp29  
M
{zzXE[@  
public static void log(int sMsg) A) p}AEBc  
{ \,[Qg#W$u  
System.err.println(sMsg); 'Y6{89y  
} Kom$i<O?48  
} TF|GGYi  
)rz
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{LJwW*?  
/* 9+9}^B5@A  
**TestMethod.java '/b,3:  
*/ $WnK  
package NetFox; #@Zz Bf  
B[C2uVEX:  
zrU0Y
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public class TestMethod { q+dY&4&u  
H]"Z_n_  
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public TestMethod() -n!.PsGO>  
{ ///xx/weblogic60b2_win.exe I o7pp(  
try{ 9fvy)kX;s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;38DBo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _+wou(1y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @= 6}w_  
fileFetch.start(); 3w ?)H  
} c>!>D7:7  
catch(Exception e){e.printStackTrace ();} >t'/(y  
]0xbvJ8oK  
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} @8|-
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9Z6] ];8E  
rYeFYPS  
public static void main(String[] args) bL!NT}y`  
{ f'aUo|^?  
new TestMethod(); DuZ51[3_L  
} /81Ux@,(e  
} /Y:_qsO1  
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