http断点续传简单实现（java)

/* 6/%dD 
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**SiteFileFetch.java H'Oy._,]t  
*/ /e2CB"c  
package NetFox;  ^n5rUwS>  
import java.io.*; nE2w?  
import java.net.*; O;34~k   
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public class SiteFileFetch extends Thread { Skbd'j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u%o]r9xl'  
long[] nStartPos; //开始位置 d;4LHQ0yU  
long[] nEndPos; //结束位置 tRl01&0S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g+X .8>=  
long nFileLength; //文件长度 2ncD,@ij  
boolean bFirst = true; //是否第一次取文件 ~yGD("X  
boolean bStop = false; //停止标志 #cnh ~O  
File tmpFile; //文件下载的临时信息 ($h`Y;4  
DataOutputStream output; //输出到文件的输出流 2@A%;f0Q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yGxAur=dE  
public SiteFileFetch(SiteInfoBean bean) throws IOException (R9{wGV [  
{ l"{1v~I  
siteInfoBean = bean; V!{}%;f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fj7\MTy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vhEqHjR:  
if(tmpFile.exists ()) 2`Ojw_$W7  
{ =ObI  
bFirst = false; 3Uy48ue  
read_nPos(); 8p;|&7  
} >8*0"Q  
else U '$W$()p  
{ HGwSso
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nStartPos = new long[bean.getNSplitter()]; Q{:5gh  
nEndPos = new long[bean.getNSplitter()]; c*k%r2'  
} ]T?Py)  
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} XK";-7TZt  
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public void run() ?xRx|_}e  
{ jDV;tEY#^  
//获得文件长度 c)b/"  
//分割文件 tF/)DZ.to  
//实例FileSplitterFetch !:GlxmtoW?  
//启动FileSplitterFetch线程 -J06H&/k  
//等待子线程返回 X0}+X'3  
try{ 6dNW2_  
if(bFirst) 6H#4iMeh  
{ |h7 d#V>  
nFileLength = getFileSize(); 0E<xzYo  
if(nFileLength == -1) MzRliH8e  
{ `hVi!Q]*P  
System.err.println("File Length is not known!"); @{X<|,W9w  
} J[k,S(Y  
else if(nFileLength == -2) G0izZWc  
{ ?_@_NV MY  
System.err.println("File is not access!"); BM vG
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} z>6hK:27  
else 4GN  
{ #hQ#_7  
for(int i=0;i<nStartPos.length;i++) NKSK+ll2  
{ ;UAi>//#   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qvx[F:#Tk  
} P4VMGP  
for(int i=0;i<nEndPos.length-1;i++) YcmLc)a7  
{ 
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nEndPos = nStartPos[i+1]; F?Fs x)2k  
} 4#D<#!]^  
nEndPos[nEndPos.length-1] = nFileLength; (v)/h>vS  
} w<P$)~6  
}
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//启动子线程 MB!_G[R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jY+uOH  
for(int i=0;i<nStartPos.length;i++) V#P`FX  
{ 8k0f&Cak=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r3BQo[ 't  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TOx >Z  
nStartPos,nEndPos,i); <NYf!bx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !P"@oJ/Yy_  
fileSplitterFetch.start(); XzD+#+By  
} Q`BK R]/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mWP1mc:M(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uE]Z,`e
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *
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nEndPos = " + nFileLength); AhCqQ.O71  
// fileSplitterFetch[nPos.length-1].start(); >* )fmfY  
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ZYexW=@  
//等待子线程结束 .*k$abb  
//int count = 0; ~x-v%x6  
//是否结束while循环 I"hlLP  
boolean breakWhile = false; yW)&jZb"(  
I)AbH<G{  
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while(!bStop) Ds<~JfVl  
{ +I>V9%%vW_  
write_nPos(); $[xS>iuD  
Utility.sleep(500); r1A<XP|1?I  
breakWhile = true; 49Q tfk  
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for(int i=0;i<nStartPos.length;i++) 51Q m2,P1^  
{ Q|7$SS6$  
if(!fileSplitterFetch.bDownOver) ?lPyapA]  
{ {u(( y D  
breakWhile = false; TCLXO0  
break; Pea2ENe3  
} @km@\w  
} 1va~.;/rG  
if(breakWhile) :AYhBhitC  
break; h0oe'Xov  
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//count++; oO4hBM([  
//if(count>4) :?P>))vT%  
// siteStop(); [q!/YL3%  
} q\n,/#'i~  
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System.err.println("文件下载结束！"); n|N?[)^k  
} o FS2*u  
catch(Exception e){e.printStackTrace ();} M/J?$j  
} L:_GpZ_  
)jPIBzMys  
: =f!>_r+  
//获得文件长度 i1 >oRT{Z  
public long getFileSize() rT"3^,,  
{ kQw%Wpuq[/  
int nFileLength = -1; V~ q b2$  
try{ [aF"5G
  
URL url = new URL(siteInfoBean.getSSiteURL()); %5ovW<E:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WS6;ad;|  
httpConnection.setRequestProperty("User-Agent","NetFox"); BS|$-i5L  
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int responseCode=httpConnection.getResponseCode(); ;u*I#)7  
if(responseCode>=400) %:!ILN  
{ <;lwvO  
processErrorCode(responseCode); .
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return -2; //-2 represent access is error +:kMYL3  
} Y.b?.)u&  
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String sHeader; {l9g
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for(int i=1;;i++) '>k1h.i  
{ yXT.]%)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }B ?_>0  
//Utility.log(in.readLine()); M)"'Q6ck=  
sHeader=httpConnection.getHeaderFieldKey(i); @gnLY  
if(sHeader!=null) jR2^n`D  
{ odTa2$O  
if(sHeader.equals("Content-Length")) .G-L/*&%  
{ <)a7Nrc\T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SajasjE!^1  
break; +n>
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} ix
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} "9X1T]  
else #+Y%Bxf  
break; 6&;h+;h  
} &Lbh?C  
} *|as-!${k  
catch(IOException e){e.printStackTrace ();} <8ih >s(C  
catch(Exception e){e.printStackTrace ();} U'LPaf$O  
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Utility.log(nFileLength); ~~3*o  
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return nFileLength; UCo`l~K)qg  
} Z]XjN@j"  
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//保存下载信息（文件指针位置） &N*l?7(  
private void write_nPos() i8A-h6E  
{ ;]l`Q,*OXb  
try{ K SJ Ko  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YQ>O6:%  
output.writeInt(nStartPos.length); H6hhU'Kxf8  
for(int i=0;i<nStartPos.length;i++) E>N[  
{ >mj WC) U  
// output.writeLong(nPos); aMJJ|iiU  
output.writeLong(fileSplitterFetch.nStartPos); vDIsawbHD  
output.writeLong(fileSplitterFetch.nEndPos); QIfP%,LT  
} `$MO;Fv,G  
output.close(); uT>"(wnJ|  
} ?_d3
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catch(IOException e){e.printStackTrace ();} hd W7Qck"  
catch(Exception e){e.printStackTrace ();} 6a704l%#hb  
}
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//读取保存的下载信息（文件指针位置） v0(_4U]/  
private void read_nPos() K7t_Q8  
{ aF[#(PF  
try{ 7AF6aog  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =@D H hg  
int nCount = input.readInt(); )"J1ET,z  
nStartPos = new long[nCount]; u
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nEndPos = new long[nCount]; !p Q*m`Xo  
for(int i=0;i<nStartPos.length;i++) 9&zQ5L>  
{ sJMpF8   
nStartPos = input.readLong(); Wf~PP;  
nEndPos = input.readLong(); VAp 1{  
} YIF|8b\  
input.close(); ]*D~>q"#\  
} 3G'cDemc  
catch(IOException e){e.printStackTrace ();} ^iWJqpLe  
catch(Exception e){e.printStackTrace ();} 81!gp7c  
} +LlAGg]Z  
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private void processErrorCode(int nErrorCode) p!EG:B4  
{ Z= =c3~  
System.err.println("Error Code : " + nErrorCode); |Yv,zEY)  
} l=L(pS3 ~  
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//停止文件下载 .hjN*4RY  
public void siteStop() K1w:JA6(  
{ L) UCVm  
bStop = true; 2t?Vl%<  
for(int i=0;i<nStartPos.length;i++) =7EkN% V:{  
fileSplitterFetch.splitterStop(); )6%a9&~H  
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} /4}y2JVv)  
} cUO$IR)yL  
//负责部分文件的抓取 vGOO"r(xL  
**FileSplitterFetch.java X<H{  
*/ DT
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package NetFox; @+a}O  
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import java.io.*; u $B24Cy.  
import java.net.*; ^O}J',Fm%f  
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public class FileSplitterFetch extends Thread { 2cwJ);Eg2  
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String sURL; //File URL gGx<k3W^  
long nStartPos; //File Snippet Start Position ND/oKM+?  
long nEndPos; //File Snippet End Position h gu\~}kD  
int nThreadID; //Thread's ID 6!8uZ>u%Vg  
boolean bDownOver = false; //Downing is over )@<HG$#  
boolean bStop = false; //Stop identical |{RCvm  
FileAccessI fileAccessI = null; //File Access interface !}sF#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
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{ w_DaldK*  
this.sURL = sURL; s<oT,SPt  
this.nStartPos = nStart; P.jy7:dB,  
this.nEndPos = nEnd; %/BBl$~ji  
nThreadID = id; 221}xhn5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b;nqhO[f}  
} o6:@j#b  
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public void run() vQj{yJ\l1  
{ TmK8z  
while(nStartPos < nEndPos && !bStop) ?A04qk  
{ )\7Cp-E-W  
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try{ orbz`IQc  
URL url = new URL(sURL); -:~z,F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hLVgP&/E  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,1]VY/  
String sProperty = "bytes="+nStartPos+"-"; \FF|b"E_=  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); @Fzw_qr M  
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InputStream input = httpConnection.getInputStream(); Z-yoJZi  
//logResponseHead(httpConnection); PZ#aq~>w
 
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byte[] b = new byte[1024]; 4G hg~0  
int nRead; L">m2/ HG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) er2;1TW3E  
{ EfkBo5@Qi  
nStartPos += fileAccessI.write(b,0,nRead); P@x@5
uC2  
//if(nThreadID == 1) K)}Vr8,V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); # %'%LY=  
} )\kNufP  
~#)9Kl7<X  
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Utility.log("Thread " + nThreadID + " is over!"); 1lJ^$U  
bDownOver = true; k(v &+v  
//nPos = fileAccessI.write (b,0,nRead); Do5{t'm3  
} i[w&!mn%  
catch(Exception e){e.printStackTrace ();} B9,  
} 7[i&EPN
 
} kBY#=e).  
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//打印回应的头信息 88 ca  
public void logResponseHead(HttpURLConnection con) L(
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{ BqdGU-Q  
for(int i=1;;i++) 9;rZ)QD  
{ Q5u3~Q'e  
String header=con.getHeaderFieldKey(i); O2fFh_\  
if(header!=null) Zu>CR_C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v[R_6  
Utility.log(header+" : "+con.getHeaderField(header)); 5HTY ~&C  
else F=f9##Y?7M  
break; )i\foSbB`V  
} SRU#Y8Xv|  
} 1v<uA9A%[  
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public void splitterStop() 1^[]#N-Bu  
{ NxB/U_j  
bStop = true; ;=@?( n  
} ?%/*F<UVQ  
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} ha9 dz  
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/* NH1ak(zHW  
**FileAccess.java y5Fgf3P@ju  
*//文件访问(定位，写) LmUR@ /VQ  
package NetFox; ,S~A]uH'  
import java.io.*; 4 XGEw9`3  
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public class FileAccessI implements Serializable{ 2d<`dQY{l3  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D2io3Lo$ov  
RandomAccessFile oSavedFile; }/g1  
long nPos; v[a4d&P  
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public FileAccessI() throws IOException akwS;|SZ  
{ h(^[WSa  
this("",0); maV*+!\  
} "c![s%  
9Z3Vf[n5\  
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public FileAccessI(String sName,long nPos) throws IOException WckWX]};S  
{ pwF])uf*{\  
oSavedFile = new RandomAccessFile(sName,"rw"); Hq,NOP  
this.nPos = nPos; eEeK ]8@  
oSavedFile.seek(nPos); gV'=uz v  
} 7'@~TM  
wB<cW>6  
{P%\& \{F  
public synchronized int write(byte[] b,int nStart,int nLen) t~Ic{%bdA  
{ ZKi?;ta=  
int n = -1; Yof]  
try{
AZ
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oSavedFile.write(b,nStart,nLen); "<"s&ws;k  
n = nLen; 4X0ku]  
} b'RBel;W  
catch(IOException e) j'UWgwB  
{ 7qdB  
e.printStackTrace (); }c#W"y5l_  
} "2T* w~V&y  
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return n; AO8%!+"_  
} T3-/+4$0v  
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} (]5gYi
 
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/* e^hI[LbNC  
**SiteInfoBean.java I3Ad+]v  
*/ p >nKNd_aQ  
package NetFox; \r&(l1R  
'tVe#oI  
Wa%p+(\<uB  
public class SiteInfoBean { X C'|  
GEki34 n0  
i\RB KF  
private String sSiteURL; //Site's URL Ul:M=8nE%  
private String sFilePath; //Saved File's Path &VVvZ@X;  
private String sFileName; //Saved File's Name [kI[qByf  
private int nSplitter; //Count of Splited Downloading File quFNPdP  
q]y{ 4"=5  
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public SiteInfoBean() eW[](lGWM  
{//nSplitter的缺省值为5 )U{IQE;T#  
//default value of nSplitter is 5 \Zn~y--Z  
this("","","",5); w X.]O!^X~  
} `V?NS,@$  
")W5`9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Oq95zo  
{ r
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sSiteURL= sURL; pAcu{5#7  
sFilePath = sPath; ~B`H5#  
sFileName = sName; *,wW-8  
this.nSplitter = nSpiltter; UR[UZ4G  
=AeOkie  
No]#RvEd3  
} oCB#i~|>a  
w5a;ts_x  
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public String getSSiteURL()
h9+76  
{ Ia>~ph#]{`  
return sSiteURL; :) T#.(mR  
} wgZ6|)!0  
IZZ $p{  
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public void setSSiteURL(String value) 7nbaR~ZV  
{ 4TaHS!9  
sSiteURL = value; szy2"~hm  
} Kp/l2?J"  
'Y>@t6E4  
,^qHl+'  
public String getSFilePath() N\zUQ J  
{ SdJkno  
return sFilePath; t},71Ry  
} D*)"?LG  
7:OF>**  
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public void setSFilePath(String value) jft@ 'W53  
{ Q7?[@2HN  
sFilePath = value; -M`+hVs?  
} }
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/Fp@j/50  
public String getSFileName() +<c(;Ucl?  
{ 7T=:dv  
return sFileName; g|)yM^Vqr6  
} ?;p45y~n%  
wUmcA~3D  
xc$jG?83#  
public void setSFileName(String value) wmit>69S  
{ +\MGlsMK@.  
sFileName = value; YHo*IX')C?  
} =|q@Q`DB  
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public int getNSplitter() \xOv9(  
{ l`*R !\  
return nSplitter; Mog!pmc{  
} Y!_e,]GW  

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79ZYRm2;  
public void setNSplitter(int nCount)  lmB+S  
{ O)}5`0@L  
nSplitter = nCount; =2, iNn  
} -2y>X`1Y  
} B%KfB VC  
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h7
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/* ~0
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**Utility.java (Bu-o((N@0  
*/ i8`0-  
package NetFox; stlkt>9  
DX8pd5U  
);ZxKGjc4  
public class Utility { RMBPm*H  
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public Utility() }&IOBYHVDo  
{ Uj>bWa`  
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} {us"=JJVN  
Lz}mz-N  
//线程睡眠 N uq/y=  
public static void sleep(int nSecond) wnbKUlb  
{ ~ ^)4*@i6  
try{ 0uf)6(f  
Thread.sleep(nSecond); 0-zIohSJdQ  
} xX{gm'3UYa  
catch(Exception e) P}mn2Hs  
{ N(L?F):fT  
e.printStackTrace (); c=~FXV!  
} Vw b6QIs  
} /}RW~ax  
(T2\   
//日志 M`.v/UQn  
public static void log(String sMsg) |1^ !rHg  
{ kY`L[1G$  
System.err.println(sMsg); _0qp!-l}  
} DsF<P@O6  
@(LEuYq}  
8hm|9  
public static void log(int sMsg) 5j-?Uf  
{ bupDnTF  
System.err.println(sMsg); :LBRyBV  
} aak[U;rx  
} tD\%SiTg=b  
%P-z3 0FHp  
d@_|  
/* 63y&MaqSJ  
**TestMethod.java ma(E}s  
*/ GJ4R f%  
package NetFox; OO`-{HKt  
haIH `SY  
1A-ess\  
public class TestMethod { R3gg{hQ  
8iwqy0<  
(uskVK>L  
public TestMethod() @If ^5s;z  
{ ///xx/weblogic60b2_win.exe Y+UM>  
try{ SFx|9$hXm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )%]`uj>*[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zQ~8(E]Rf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qx<h rC0Z&  
fileFetch.start(); O%?d0K  
} <hSrx7o  
catch(Exception e){e.printStackTrace ();} ~
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%(y0,?*  
Z 361ko}  
} /4PV<[ :_  
BX=YS)  
*FrlzIAom  
public static void main(String[] args) ]Sgc42hk  
{ 0413K_  
new TestMethod(); *P}v82C N  
} Y]gb`z$?  
} 9>na3ISh  
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