http断点续传简单实现（java)

/* ;Xr|['\'  
**SiteFileFetch.java $2
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*/ 8kRqF?rbj  
package NetFox; G/)]aGr  
import java.io.*; lTR/o  
import java.net.*; i&di}x  
[(O*W  
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public class SiteFileFetch extends Thread { ((AsZ$[S  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j,Vir"-)  
long[] nStartPos; //开始位置 [_X.Equ  
long[] nEndPos; //结束位置 ([#4H3uO-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n>o0PtGxC  
long nFileLength; //文件长度 l&2pUv=  
boolean bFirst = true; //是否第一次取文件 4b
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boolean bStop = false; //停止标志 YCBcyE}p  
File tmpFile; //文件下载的临时信息 (rT1wup  
DataOutputStream output; //输出到文件的输出流 Rf4}4ixkj  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d1{%z\u a  
public SiteFileFetch(SiteInfoBean bean) throws IOException ExW3LM9(  
{ Vz\?a8qQ<  
siteInfoBean = bean; +\ZaVi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P.t0o~hoK;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o-ee3j.  
if(tmpFile.exists ()) B*-A erdH  
{ g,O3\jjQ  
bFirst = false; jTh^#Q  
read_nPos(); g.:b\JE`  
} C]f`  
else |'SgGg=E  
{ b]oPx8*'  
nStartPos = new long[bean.getNSplitter()]; r.vezsH  
nEndPos = new long[bean.getNSplitter()]; *ak"}s  
} d^:(-2l-  
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} ~]l T>|X  
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public void run() abczW[\  
{ RHj<t");  
//获得文件长度 &f"kWOe$X  
//分割文件 rP<S =eb  
//实例FileSplitterFetch TPi=!*$&  
//启动FileSplitterFetch线程 -udKGrT+  
//等待子线程返回 Gc0/*8u/  
try{ j-n-2:Q  
if(bFirst) B4/\RC2  
{ Z]\IQDC  
nFileLength = getFileSize(); )2
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if(nFileLength == -1) })TXX7[h  
{ s6HfN'  
System.err.println("File Length is not known!"); h;RKF\U:"  
} E!6Nf[  
else if(nFileLength == -2) M!Wjfq ^~  
{ a(|,KWHn  
System.err.println("File is not access!"); 92pl#Igt  
} qCUn. mI  
else F
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{ rd0[(-  
for(int i=0;i<nStartPos.length;i++) t)n}S;iD  
{ [Fo"MeH?R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5a^b{=#Y  
} --'!5)U  
for(int i=0;i<nEndPos.length-1;i++) 24L =v  
{ kfQi}D'a  
nEndPos = nStartPos[i+1]; x/]]~@:  
} qs 0'}>  
nEndPos[nEndPos.length-1] = nFileLength; WVkJ=r0Ny  
} "<^]d~a_  
} AriW&E  
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//启动子线程 W:TF8Onw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KU5|~1t 4  
for(int i=0;i<nStartPos.length;i++) dZi?Z  
{ 9+"\7MHw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ge@KopZ&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zZ})$Ny(  
nStartPos,nEndPos,i); G&f~A;'7k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WY`hNT6M  
fileSplitterFetch.start(); qR>"r"Fq  
} \Bg?QhA_D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ztG!NZL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -<RG'I~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 50VH>b_  
nEndPos = " + nFileLength); *5Aq\g,n  
// fileSplitterFetch[nPos.length-1].start(); DAHQ7#qfQC  
Lr;PESV  
.V'=z|   
//等待子线程结束 GJB=5nE  
//int count = 0; "JBTsQDj!  
//是否结束while循环 P3u,)P&  
boolean breakWhile = false;  b :J$  
c=Y8R/G<  
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while(!bStop) Ad'b{C%  
{ %I>-_el  
write_nPos(); :Tu%0="ye  
Utility.sleep(500); ),#hBB`ZA  
breakWhile = true; V/@?KC0B5  
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@w]z"UCwV@  
for(int i=0;i<nStartPos.length;i++) Dw-i!dq  
{ n>-"\cjV  
if(!fileSplitterFetch.bDownOver) FY(C<fDRo{  
{ I'$}n$UvZ  
breakWhile = false; #'?gMVSk  
break; wn-{Vkpm  
} <xpHlLc  
} xO nW~Z  
if(breakWhile) ( /):  
break; ``j8T[g  
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z')zVoW,  
//count++; /H m),9NN  
//if(count>4) v?S~ =$.  
// siteStop(); xM6v0Ua  
} #{]Yw}m  
UvPD/qu$8D  
3Q-[)Z )  
System.err.println("文件下载结束！"); 28rC>*+z  
} |DZ3=eWZ  
catch(Exception e){e.printStackTrace ();} w6w'Jx  
} cHO8%xu`  
|'bRVqJ  
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//获得文件长度 MlBw=Nr  
public long getFileSize() !`VC4o  
{ tq^d1b(j4  
int nFileLength = -1; wWU5]v  
try{ o"5[~$O  
URL url = new URL(siteInfoBean.getSSiteURL()); oF9c>^s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Lq{_Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^%<t^sE  
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int responseCode=httpConnection.getResponseCode(); ])YGeY(V0+  
if(responseCode>=400) YEB@p.  
{  :Ky *AI  
processErrorCode(responseCode); eJm7}\/6`  
return -2; //-2 represent access is error Q'mLwD3>  
} _=\=oC  
[=xJh?*P  
on=I*?+R  
String sHeader; QaMB=wV
r  
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for(int i=1;;i++) &D[pX|!  
{ h
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P4~=_Hh  
//Utility.log(in.readLine()); ggR--`D[  
sHeader=httpConnection.getHeaderFieldKey(i); .{@aQwN  
if(sHeader!=null) xWa96U[  
{ Qn*a#]p  
if(sHeader.equals("Content-Length"))  p@se 5~  
{ ra'h\m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m<cvx3e  
break; I )LO@  
} +[sZE X  
} @/m|T]'8  
else ctzaqsr  
break; +.RC{o,  
} jD eNCJ  
} %%w/;o!c  
catch(IOException e){e.printStackTrace ();} jW G=k#WN  
catch(Exception e){e.printStackTrace ();} /W,K% s]  
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Utility.log(nFileLength); {MaFv  
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return nFileLength; <R?_Yjsw  
} (Wm4JmX%  
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//保存下载信息（文件指针位置） t#0/_tD  
private void write_nPos() dK45&JHoW^  
{ HcrI3v|6  
try{ 8] BOq:
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); 71h?t`N  
output.writeInt(nStartPos.length); N{(Q,+ ~  
for(int i=0;i<nStartPos.length;i++) f~3_Rv!  
{ E|aPkq]  
// output.writeLong(nPos); 1M4I7*r  
output.writeLong(fileSplitterFetch.nStartPos); ]757oAXl  
output.writeLong(fileSplitterFetch.nEndPos); nv9kl Q@  
} +cw;a]o^>  
output.close(); )/hb9+S  
}  ThLnp@  
catch(IOException e){e.printStackTrace ();} <Y
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catch(Exception e){e.printStackTrace ();} V|h/a\P  
} t1I` n(]n  
>9S@:?^&q>  
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//读取保存的下载信息（文件指针位置） 73C  
private void read_nPos() AV0C9a/td  
{ 1f"LAs`%  
try{ ZXf^HK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $1CAfSgKw  
int nCount = input.readInt(); -cjwa-9 ~  
nStartPos = new long[nCount]; Ikkv <uY  
nEndPos = new long[nCount]; Y68T&swD  
for(int i=0;i<nStartPos.length;i++) =DhzV D  
{ '5ZtB<  
nStartPos = input.readLong(); D&xbtJd  
nEndPos = input.readLong(); u'?yc"d>#  
} U
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input.close(); f&\v+'[p  
} -}Jf4k#G  
catch(IOException e){e.printStackTrace ();} 6tE<`"P!  
catch(Exception e){e.printStackTrace ();} =/k*w#j  
} O!b >  
l+>&-lX'  
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private void processErrorCode(int nErrorCode) l"\W]'T:r  
{ \gh`PS-B  
System.err.println("Error Code : " + nErrorCode); WrR97]7t  
} @+v;B:  
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s^/<6kwO  
//停止文件下载 y<G@7?  
public void siteStop() EcA@bZ0  
{ 
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bStop = true; *CA7 {2CX  
for(int i=0;i<nStartPos.length;i++) Ba$Ibq,r/  
fileSplitterFetch.splitterStop(); #K3A{ jb,  
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} .Qpqbp 8  
} y:0j$%^  
//负责部分文件的抓取 V4RtH  
**FileSplitterFetch.java 2Et7o/\<  
*/ k-LB %\p  
package NetFox; Tm8c:S^uq)  
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import java.io.*; X5'QYZ6kv  
import java.net.*; }ST9&wi~  
M'=27!D^  
*3hqz<p4:  
public class FileSplitterFetch extends Thread { 3f`+-&|M  
UGy~Ecv  
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String sURL; //File URL g+ik`q(ge  
long nStartPos; //File Snippet Start Position y[*Bw)F\N  
long nEndPos; //File Snippet End Position zS*X9|p  
int nThreadID; //Thread's ID Z#wmEc.}C  
boolean bDownOver = false; //Downing is over ^/Id!Y7  
boolean bStop = false; //Stop identical eD0Rv0BV^  
FileAccessI fileAccessI = null; //File Access interface lO-:[@  
*pMgjr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :@TfhQV_=Q  
{ t@Qs&DZ7k  
this.sURL = sURL; G[YbgG=9Y  
this.nStartPos = nStart; &)Fp  
this.nEndPos = nEnd; Oj#nF@U  
nThreadID = id; Z2Bl
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;as4EqiK  
} m8Q6ESg<*u  
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public void run() y ?FKou'  
{ ellj/u61bj  
while(nStartPos < nEndPos && !bStop) V4GcW|P4y  
{ eKlh }v  
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try{ 6]dK,  
URL url = new URL(sURL); 8X`Gm!)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c <[?Z7y  
httpConnection.setRequestProperty("User-Agent","NetFox"); @Z.s:FV[  
String sProperty = "bytes="+nStartPos+"-"; |IqQ%;H  
httpConnection.setRequestProperty("RANGE",sProperty); K9FtFd  
Utility.log(sProperty); n&x#_
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InputStream input = httpConnection.getInputStream(); -Cxk#-sb#  
//logResponseHead(httpConnection); n&=3Knbd@d  
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byte[] b = new byte[1024]; NZ`( d  
int nRead; d%Zt]
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7d?'~}j  
{ #/ 1  
nStartPos += fileAccessI.write(b,0,nRead); 5
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//if(nThreadID == 1) pHlw&8(f"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nhv~f0  
} 7p&%0'BO1z  
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Utility.log("Thread " + nThreadID + " is over!"); DCv~^  
bDownOver = true; m!s/L,iJJ  
//nPos = fileAccessI.write (b,0,nRead); $-m`LF@  
} 6elmLDMni\  
catch(Exception e){e.printStackTrace ();} *5iNw_&  
} B98&JoS  
} g]9!Pi8jn  
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=&~*r  
//打印回应的头信息 o'@VDGS`  
public void logResponseHead(HttpURLConnection con) vV:eU-a  
{ 2HBYReQ  
for(int i=1;;i++) UBp0;)-  
{ Bry\"V"'g  
String header=con.getHeaderFieldKey(i); +(VHnxNQs  
if(header!=null) eN@V?G26K  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); F{\MIuoy  
else -.:[a3c?  
break; -"iGcVV  
} 5QU7!jbI  
} 2E^zQ>;01  
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m]J
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public void splitterStop() t%<nS=u  
{ [^B04
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bStop = true; _ 97  
} w?A&XB+  
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} MV5'&" ,oB  
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/* FA?xp1E  
**FileAccess.java r*<)QP^B~  
*//文件访问(定位，写) ]?tsYXU j  
package NetFox; <l(6$~(-u  
import java.io.*; RuDn1h#u{  
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public class FileAccessI implements Serializable{ $Ml/=\EHOg  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r'M|mQ$s>  
RandomAccessFile oSavedFile; FMB\$(g  
long nPos; wxpE5v+f|  
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public FileAccessI() throws IOException L,0HX   
{ hHF YAh   
this("",0); g?!vRid@S  
} 3!&lio+<  
;=1]h&S  
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public FileAccessI(String sName,long nPos) throws IOException <#JJS}TLk  
{ DoAK]zyJA  
oSavedFile = new RandomAccessFile(sName,"rw"); e!
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this.nPos = nPos; 1SeDrzLA  
oSavedFile.seek(nPos); (UPkb$Qc  
}  3}}~(  
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2`/
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public synchronized int write(byte[] b,int nStart,int nLen) wy"^a45h  
{ 0PD]#.
+  
int n = -1; R| t"(6  
try{ |U%
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oSavedFile.write(b,nStart,nLen); O/$pT%D1x  
n = nLen; Oz!#);v  
} ,T?8??bZ  
catch(IOException e) "40Jxqt  
{ .P.TqT@)r  
e.printStackTrace (); _|rrl
 
} ]kx)/n-K  
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return n; :<4:h.gO8  
} d9h"Q  
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} *_}|EuY  
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/* bvzeUn  
**SiteInfoBean.java h"cLZM:6  
*/ :ak D
 
package NetFox; NJSzOL_  
sF
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public class SiteInfoBean { O{rgx~lLJt  
[R-4e; SRh  
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private String sSiteURL; //Site's URL ww82)m8  
private String sFilePath; //Saved File's Path t=J\zyX!  
private String sFileName; //Saved File's Name 2KMLpO&De  
private int nSplitter; //Count of Splited Downloading File |5S/h{gq  
a@Tn_yX  
l j*ELy  
public SiteInfoBean() <n< @ O5  
{//nSplitter的缺省值为5 fRC(Yyx  
//default value of nSplitter is 5 gsd9QW  
this("","","",5); Au &NQ+  
} Ffk$8"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T1m'+^?"  
{ t QkEJ pj  
sSiteURL= sURL; $>1 'pV  
sFilePath = sPath; )nU%}Z  
sFileName = sName; Fv=7~6~  
this.nSplitter = nSpiltter; bs$x%CR  
jC>l<d_  
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} [,)yc/{*  
De,4r(5  
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public String getSSiteURL() e|u|
b  
{ b}4k-hZL  
return sSiteURL;  Hi#'h  
} ysD@yM,  
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68?oV)fE  
public void setSSiteURL(String value) h"/FqO  
{ mcAg,~"HB  
sSiteURL = value; w V&{w7  
} GCCmUR9d  
w_|R.T\7  
2P`QS@v0a=  
public String getSFilePath() =\.Oc+p4  
{ 'jWd7w~(  
return sFilePath; c0jdZ#H  
} [b-27\b  
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e_s9E{(  
public void setSFilePath(String value) *f|9A/*B3  
{ T">-%-t  
sFilePath = value; 2T/C!^iJ)  
} +N1oOcPC>C  
=ZM#_uW  
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public String getSFileName() '(A)^K>+  
{ T0n=nC}<  
return sFileName; %\#s@8=2u  
} J&UFP{)  
bA\TuB  
Q/r0p>  
public void setSFileName(String value) }ny,Nl  
{ L'=2Uk#.D  
sFileName = value; ?P4@U9i  
} -IhFPjQ  
+%(iGI{  
c7T9kV8hS  
public int getNSplitter() Gb+cT  
{ %J4]T35^2  
return nSplitter; 3`_jNPV1  
} bf2R15|t5`  
xExy?5H7  
-dbD&8  
public void setNSplitter(int nCount) [tDUR  
{ % INRds  
nSplitter = nCount; B%!z7AT  
} 2zR*`9$  
} J7X-=E D  
1 Y_e1tgmm  
RbX!^v<0f6  
/* .{ ^4I  
**Utility.java S W(h%`U  
*/ 0-cqux2U  
package NetFox; CBdSgHA3>  
7onMKMktM%  
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public class Utility { 6ae  
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public Utility() F4X/ )$Dk  
{ 'TpW-r:  
F^bC!;~x  
{V%ZOdg9  
} Ib.`2@o&  
'JY*K:-  
//线程睡眠 Zzr+p.  
public static void sleep(int nSecond) w] LN(o:  
{ Frn#?n)S9  
try{ 9PhdoREb  
Thread.sleep(nSecond); @<Au|l`  
} Ls#
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catch(Exception e) i.2O~30ST  
{ ~LGkc t  
e.printStackTrace (); ElAJR4'{*i  
} adtK$@Yeg  
} 6"Q/Y[y  
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//日志 %Q"zU9  
public static void log(String sMsg) , M$*c  
{ x-+[gNc 6  
System.err.println(sMsg); pWH
8ex+  
} lGqwB,K$z4  
f ^mxj/%L  
|o~<Ti6]  
public static void log(int sMsg) B#o(21s  
{ K !8+~[  
System.err.println(sMsg); yAtM|:qq  
} f|Kd{ $VO  
} (u85$
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A$ %5l  
/* m s\:^a  
**TestMethod.java iQ*JU2;7t  
*/ l;U9dO}/[  
package NetFox; Pgf$GXE  
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o1"U'y-9V  
public class TestMethod { @I}:HiF  
LfyycC2E  
tp$NT.z  
public TestMethod() &J^@TgqL^  
{ ///xx/weblogic60b2_win.exe R6dw#;6{I  
try{ |tz1'YOB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R?1;'pvpa[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
x(3E#7>1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); W-=~Afy  
fileFetch.start(); U jVo "K  
} rS/Q  
catch(Exception e){e.printStackTrace ();} lW'6rat  
s2g}
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D9e"E1f+"  
} hU5[k/ q  
}txHuq1Q.  
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public static void main(String[] args) N::_JH?^=  
{ h3aHCr E  
new TestMethod(); KQ?E]}rZ  
} ?nrd$,
 
} kJy<vb~   
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