http断点续传简单实现（java)

/* !X5o7b)  
**SiteFileFetch.java n0rerI[R  
*/ B>~k).M&,  
package NetFox; 
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import java.io.*; ./"mn3U  
import java.net.*; +(;8@"u  
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public class SiteFileFetch extends Thread { !Oeq G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [ 3$.*   
long[] nStartPos; //开始位置 t{_!Z(Rt5)  
long[] nEndPos; //结束位置 2Ryp@c&r^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N=>- Q)  
long nFileLength; //文件长度 Y.DwtfE  
boolean bFirst = true; //是否第一次取文件 n=f`AmF;  
boolean bStop = false; //停止标志 yJnPD/i  
File tmpFile; //文件下载的临时信息 X3P&"}a  
DataOutputStream output; //输出到文件的输出流 ^Vag1(hdq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7<^'DOs  
public SiteFileFetch(SiteInfoBean bean) throws IOException q&u$0XmV  
{ W;^N8ap%  
siteInfoBean = bean; `Jn,IDq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OZ
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?sV[MsOsC  
if(tmpFile.exists ()) {J{1`@  
{ [!^cd%l  
bFirst = false; ;xL67e%?  
read_nPos(); gzor%)C  
} Y;8 >=0ye  
else P?uf?{  
{ #-,g&)`]  
nStartPos = new long[bean.getNSplitter()]; !]yQ1@)*'  
nEndPos = new long[bean.getNSplitter()]; ;U |NmC+  
} =KV@&Y^x4  
M /"gf;)q>  
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} ])C>\@c6Gm  
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public void run() |Td_S|:d  
{ kg:l:C)Tq  
//获得文件长度 ^b=XV&{q  
//分割文件 0Su_#".-*  
//实例FileSplitterFetch q'.;W@m  
//启动FileSplitterFetch线程 2sUbiDe-  
//等待子线程返回 3)y{n%
3L  
try{ KCD5*xH  
if(bFirst) j$+gq*I&E  
{ A]j}'  
nFileLength = getFileSize(); 3x![8 x  
if(nFileLength == -1) 57U%`  
{ i-,'.w  
System.err.println("File Length is not known!"); r ^MiRa  
} ~Yl<S(/4  
else if(nFileLength == -2) >{QdMn  
{ wk@yTTnb  
System.err.println("File is not access!"); i *B:El1  
} %lV@:"G  
else rhIGOk1k  
{ LP,9<&"<  
for(int i=0;i<nStartPos.length;i++) M\dO({o  
{ p'80d:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AVv#\JrRW  
} -?5$ PH  
for(int i=0;i<nEndPos.length-1;i++) %@P``  
{ ywEDy|Wn$~  
nEndPos = nStartPos[i+1]; x<@kjfm5  
} -AC`q/bCD  
nEndPos[nEndPos.length-1] = nFileLength; O~6Q;qP  
} *0~M
 
} x{Sd P$  
-E]Sk&4Gj  
V!xwb:J  
//启动子线程 ESIzGaM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xg} ug[  
for(int i=0;i<nStartPos.length;i++) "J!}3)n  
{ YDFCGA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /[iG5~G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f^?uY8<  
nStartPos,nEndPos,i); /l6\^Xf{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KmL$M  
fileSplitterFetch.start(); IA2GUnUhu  
} cOb4c*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [O_^MA,z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5B{k\H;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U CRAw3=  
nEndPos = " + nFileLength); sAYV)w3u"  
// fileSplitterFetch[nPos.length-1].start(); hiwIWd:H  
m?;$;x~Dj  
` 8UWE {  
//等待子线程结束 %b=p< h'(  
//int count = 0; VFSz-<L  
//是否结束while循环 ue6d~8&  
boolean breakWhile = false; {6O0.}q]&  
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{  
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while(!bStop) BS7J#8cu  
{ 94{)"w]  
write_nPos(); .oR3Q/|k]  
Utility.sleep(500); 2]2H++  
breakWhile = true; :6lwO%=F  
/K|:9Q$K6  
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for(int i=0;i<nStartPos.length;i++) `c(\i$1JY)  
{ eg3L:rk_  
if(!fileSplitterFetch.bDownOver) qS.)UaA  
{ 2*u.3,aW  
breakWhile = false; yN\e{;z`  
break; U-EhPAB@  
} bRPO:lAy  
} 6peyh_  
if(breakWhile) ]1sNmi$T  
break; O?ktWHUx  
wqy^8N[K]  
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//count++; q4ipumy*  
//if(count>4) Rri`dmH   
// siteStop(); vT7g<  
} JE!("]&  
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-$YJfQE6G  
System.err.println("文件下载结束！"); |0 !I5|<k  
} )acV-+{  
catch(Exception e){e.printStackTrace ();} 6E|S  
} IU!Ht>  
6>DLp}d  
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//获得文件长度 #?&0D>E?k  
public long getFileSize() (oaYF+T  
{ s[AA7>]3  
int nFileLength = -1; Rj6|Y"gq9  
try{ o8z)nOTO;  
URL url = new URL(siteInfoBean.getSSiteURL()); KcXpH]>!9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6G_<2bO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ue0s&WF|  
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int responseCode=httpConnection.getResponseCode(); {1~T]5  
if(responseCode>=400) <KQ(c`KW7  
{ &[j]Bp?  
processErrorCode(responseCode); ndi+xaQtG  
return -2; //-2 represent access is error n%$ &=-Fk  
} NL!9U,h5|  
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String sHeader; yA;W/I4  
#H5=a6E+q  
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for(int i=1;;i++) tu}>:mk  
{ U<bYFuS"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _H\<[-l  
//Utility.log(in.readLine()); Zdn!qyR`  
sHeader=httpConnection.getHeaderFieldKey(i); dGkgaC+  
if(sHeader!=null) JP'= UZ'  
{ >Ko[Xb-8^_  
if(sHeader.equals("Content-Length")) 9_huI'"p  
{ J(iV0LAZb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g7V_[R(6  
break; bQQVj?8jp  
} A6p`ma $L  
} ;pZ[|  
else P(ZQDTbM :  
break; edpW8eND  
} ~UPZ<  
} 'Q|c@
t  
catch(IOException e){e.printStackTrace ();} FFzH!=7T?  
catch(Exception e){e.printStackTrace ();} u#jC#u^M  
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Utility.log(nFileLength); `X -<$x  
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return nFileLength; #n7Yr,|Z  
} FvXqggfGv  
2`Gv5}LfyR  
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//保存下载信息（文件指针位置） nSS=%,?  
private void write_nPos() m<@z}%v-  
{ /A07s[L  
try{ bFGDgwe z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @ 4UxRp6+  
output.writeInt(nStartPos.length); 2{oThef[O  
for(int i=0;i<nStartPos.length;i++) @Icq1zb] y  
{ 3S"] u}  
// output.writeLong(nPos); d3^7ag%  
output.writeLong(fileSplitterFetch.nStartPos); sb.J bE8  
output.writeLong(fileSplitterFetch.nEndPos); jP=Hf=:$  
}  (^: p  
output.close(); BIMKsF Zt  
} \}dyS8  
catch(IOException e){e.printStackTrace ();} ~W{-
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catch(Exception e){e.printStackTrace ();} Ge \["`;i  
} 3W&S.$l  
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//读取保存的下载信息（文件指针位置） @;)PSp*j  
private void read_nPos() k1}hIAk3u  
{ f8n V=AQ  
try{ HW6.O|3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
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int nCount = input.readInt(); %oof}=MxCL  
nStartPos = new long[nCount]; `f`TS#V  
nEndPos = new long[nCount]; q``wt  
for(int i=0;i<nStartPos.length;i++) 5<R%H{3j  
{ q=5l4|1  
nStartPos = input.readLong(); %1}6q`:w  
nEndPos = input.readLong(); Qn+:/zA;  
} 63&^BW  
input.close(); Qc"'8kt  
} ^[q /Mw  
catch(IOException e){e.printStackTrace ();} g>j| ]6  
catch(Exception e){e.printStackTrace ();} NiSO'=y$n  
} Xe1P- 60  
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private void processErrorCode(int nErrorCode) #h'@5 l  
{ Sc$UZ/qPT  
System.err.println("Error Code : " + nErrorCode); ";NRzY  
} ]z ==  
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d7Ro}>lp  
//停止文件下载 Xu}U{x>  
public void siteStop() GjT#%GBF  
{ FN87^.^2S  
bStop = true; *@S@x{{s  
for(int i=0;i<nStartPos.length;i++) ^vni&sJ  
fileSplitterFetch.splitterStop(); wEEn?  
0^l%j8/  
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} +t!S'|C  
} 0kDBE3i#  
//负责部分文件的抓取 QU5Sy oL[  
**FileSplitterFetch.java >fs2kha  
*/ dE(tFZx  
package NetFox; H[WQ=){  
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import java.io.*; ?dq#e9  
import java.net.*; &t}?2>:  
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public class FileSplitterFetch extends Thread { 2U$"=:Cf  
j,-C{ K  
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String sURL; //File URL }*wLEa  
long nStartPos; //File Snippet Start Position {^ec(EsO#  
long nEndPos; //File Snippet End Position k$7Z^~?Fz  
int nThreadID; //Thread's ID *dsX#Iz  
boolean bDownOver = false; //Downing is over 1y5Ex:JVZT  
boolean bStop = false; //Stop identical ,T5u
'";  
FileAccessI fileAccessI = null; //File Access interface I0Ia6w9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S\ ,mR4:  
{ )e%}b-I'r  
this.sURL = sURL; !]koSw}  
this.nStartPos = nStart; MQTdk*L_]  
this.nEndPos = nEnd; {7"0,2 Hb?  
nThreadID = id; t#wmAOW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N$I03m  
} 6d|q+]x_n  
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public void run() R= 5**  
{ -j2 (R?a  
while(nStartPos < nEndPos && !bStop) -K%5(Eg  
{ \Owp
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try{ 2&LQg=O  
URL url = new URL(sURL); aMuVqZw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }SfbCa)UO  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7[#xOZT  
String sProperty = "bytes="+nStartPos+"-"; ERMa# L  
httpConnection.setRequestProperty("RANGE",sProperty); l]LxL  
Utility.log(sProperty); 4ne5=YY*  
9<1F[SS<s9  
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InputStream input = httpConnection.getInputStream(); X`r*ob  
//logResponseHead(httpConnection); :}}%#/nd  
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byte[] b = new byte[1024]; UE0$ o?  
int nRead; |zsbW9 W*m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7=}F{U  
{ [3>GGX[Ic  
nStartPos += fileAccessI.write(b,0,nRead); [0;buVU.  
//if(nThreadID == 1) /R8p]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yt0,^*t_  
} V2d,ksKwn  
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+Wn&,?3^  
Utility.log("Thread " + nThreadID + " is over!"); %:9oDK  
bDownOver = true; DC4C$AyW r  
//nPos = fileAccessI.write (b,0,nRead); ^4Uw8-/9  
} &l2TeC@;  
catch(Exception e){e.printStackTrace ();} .TB"eUy  
} \_]En43mg  
} H=c`&N7E  
L=!of{4Z(}  
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//打印回应的头信息 vp)Vb^K>  
public void logResponseHead(HttpURLConnection con) /YKMKtE  
{
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for(int i=1;;i++) Z=z%$l  
{ J>0b1  
String header=con.getHeaderFieldKey(i); 9q[;u
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if(header!=null) W[''Cc.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !7p}C-RZp  
Utility.log(header+" : "+con.getHeaderField(header)); vsyWm.E  
else |F$BvCg  
break; ,_v|#g@{  
} n.6
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} iAn'aW\TF  
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public void splitterStop() db72W x0>  
{ a$11PBi[9  
bStop = true; 0HeD{TH\  
} \.{AAj^qD  
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} Tenf:Hm/k  
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/* XFwLz  
**FileAccess.java ub:ly0;t  
*//文件访问(定位，写) f'En#-?O  
package NetFox; aEVsU|  
import java.io.*; <O~WB  
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public class FileAccessI implements Serializable{ -%c<IX>z9  
W#w.h33)#6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Do7=#|bAM  
RandomAccessFile oSavedFile; Vzlh+R>c  
long nPos; uBnoQ~Qd[z  
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public FileAccessI() throws IOException w!^~<{Kz  
{ G7LIdn=  
this("",0); Q\Kx"Y3i  
} Td\o9
 
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public FileAccessI(String sName,long nPos) throws IOException 0$.m_0H  
{ |Bo .4lX  
oSavedFile = new RandomAccessFile(sName,"rw"); _s.;eHp,  
this.nPos = nPos;  \[:/CxP  
oSavedFile.seek(nPos); n| !@1sd  
} !vD{Df>  
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public synchronized int write(byte[] b,int nStart,int nLen) {r85l\u)Q\  
{ xG2+(f#C1  
int n = -1; _D7]-3uC!  
try{ m#e3%150{  
oSavedFile.write(b,nStart,nLen); {D&9UZ
m  
n = nLen; _~'+Qe_o$5  
} VaONd0Z I  
catch(IOException e) +_l^ #?o,  
{ 9nSWE W  
e.printStackTrace (); wBk@F5\<
 
} }YhtUWz].  
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return n; ~ Hy,7  
} 5II(mSg8  
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} 
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/* {No L  
**SiteInfoBean.java a`Qot  
*/ d@C&+#QDF  
package NetFox;  )v4b  
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public class SiteInfoBean { ~p0c3*  
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nKr9#JebRC  
private String sSiteURL; //Site's URL Fm_y&7._  
private String sFilePath; //Saved File's Path FCj{AD  
private String sFileName; //Saved File's Name Q _iO(qu 6  
private int nSplitter; //Count of Splited Downloading File ti5HrKIw  
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public SiteInfoBean() [4&
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{//nSplitter的缺省值为5 !5@_j,lW(  
//default value of nSplitter is 5 Os%n{_#8  
this("","","",5); qml2XJ>  
} BQ</g* $;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G2{O9  
{ SzDKByi  
sSiteURL= sURL;
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sFilePath = sPath; #EGA#SKo
q  
sFileName = sName; ,B}I?vN.  
this.nSplitter = nSpiltter; MTGiAFE  
"L&'Fd@ZU  
:wqC8&V  
} )jrT6x^IB  
t+r:"bb  
v
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public String getSSiteURL() Q?t^@  
{ ?']h%'Q  
return sSiteURL; F1%vtk;2?  
} P>Euq'ajX  
S"mcUU}}  
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public void setSSiteURL(String value) c?2MBtnu  
{ J<gJc*Q  
sSiteURL = value; h&3YGCl  
} Z
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9Mp$8-=>7  
%#L]]-%  
public String getSFilePath() 2?C`4AR[2H  
{ 3VnQnd E  
return sFilePath; |%a4`
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} /Ss7"*JLe  
%h"z0@+  
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public void setSFilePath(String value) w@\vHH.;V  
{ (UCK;k  
sFilePath = value; @Y,7'0U  
} hJz):d>Im  
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public String getSFileName() AGP("U'u  
{ e(F42;$$  
return sFileName; 4F3x@H'  
} 'uDjFQX  
l&YKD,H};  
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public void setSFileName(String value) )&{K~i;:  
{ 8x{B~_~  
sFileName = value; D<i[LZd  
} i|)Su
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Q^K"8 ;  
public int getNSplitter() ]{~NO{0@Y  
{ [[~w0G~1  
return nSplitter; g42)7  
} `cQo0{xK  
kU-t7'?4  
\o-&f:
 
public void setNSplitter(int nCount) ZR v"h/~  
{ + 1IQYa|  
nSplitter = nCount; /"H`.LD.?  
} w=h1pwY  
} f~OU*P>V@  
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/* {K{EOB_u  
**Utility.java {j{+0V  
*/ Rd7_~.Bo  
package NetFox; d%I"/8-J  
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public class Utility { ,B&fFis  
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public Utility() l&VjUPz_  
{ GsbAlNP  
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} e7fiGl  
'evj,zFhW  
//线程睡眠 H
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public static void sleep(int nSecond) @UBjq%z  
{ wfL-oi'5  
try{ 8E&XbqP+  
Thread.sleep(nSecond); uJR%0E7!  
} U`Jy!x2m  
catch(Exception e)
.O*bILU  
{ )4?x5#  
e.printStackTrace (); !}\4utHY  
}
/<CSVJ_r  
} @\oz4^  
v]%WH~>  
//日志 dLsn\m>  
public static void log(String sMsg) xCzebG["  
{ _ 7PMmW@  
System.err.println(sMsg); >StO.Q99  
} 5G0
$  

kY,U8a3!  
1CPjil*eb  
public static void log(int sMsg) Iq+>qX  
{ D47R  
System.err.println(sMsg); dt[k\ !-v  
} e}@)z3Q<l  
} `6y{.$ z  
P X;Ed*y  

;n=. {[,  
/* ~
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**TestMethod.java Uw-p758dD  
*/ hqk}akXt  
package NetFox; LAx4Xp/  
1iL'V-y  
0w'j+  
public class TestMethod { Et"?8\"n7  
zJM S=r  
58%'UwKn  
public TestMethod() ?6c-7QV  
{ ///xx/weblogic60b2_win.exe j7FN\ cz  
try{ G5dO 3lwq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5!C_X5M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e&MC|US=\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (qn2xrV  
fileFetch.start(); ;v17K  
} wd
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catch(Exception e){e.printStackTrace ();} k{tMzx]F__  
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bW#@OrsS  
} wiOgyMdx  
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public static void main(String[] args) iDl;!b&V.  
{ AeIrr*~]B  
new TestMethod(); &)i|$J 2.  
} &Gm$:T'~  
} +,:^5{9{  
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