http断点续传简单实现（java)

/* q<xCb%#Jl  
**SiteFileFetch.java |7'df&CA  
*/ *v;2PP[^  
package NetFox; -u6bAQ  
import java.io.*; $O&b``  
import java.net.*; 9&-dTayIz  
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cvn@/qBq*t  
public class SiteFileFetch extends Thread { "%`1]Fr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d~9A+m3b_  
long[] nStartPos; //开始位置 zGb|)A~,  
long[] nEndPos; //结束位置 F+YZE[h%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e(]!GA  
long nFileLength; //文件长度 \j@OZ  
boolean bFirst = true; //是否第一次取文件 1!xQ=DU"  
boolean bStop = false; //停止标志 ,Xu-@br{  
File tmpFile; //文件下载的临时信息 ne>pOK<vZ  
DataOutputStream output; //输出到文件的输出流 Nyku4r0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )Kc<j!8-[  
public SiteFileFetch(SiteInfoBean bean) throws IOException $SlIr<'*"  
{ %f&/E"M  
siteInfoBean = bean; Z^bQ^zk-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,;EIh}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D$w6V  
if(tmpFile.exists ()) v,FU
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{ 3
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bFirst = false; ? ^0:3$La  
read_nPos(); Z)I+@2  
} [g7L&`f9  
else g;H=6JeG/  
{ ^h(ew1:  
nStartPos = new long[bean.getNSplitter()]; t|w_i-&b,  
nEndPos = new long[bean.getNSplitter()]; `l\7+0W  
} m(r,Acy6  
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} )X1{  
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public void run() %R}qg6dL  
{ , Rk9N  
//获得文件长度 OV1_|##LC  
//分割文件 0z`a1 %U  
//实例FileSplitterFetch \ ZgE  
//启动FileSplitterFetch线程 /Wi[OT14  
//等待子线程返回 I:=S0&%)  
try{ +^` I?1\UF  
if(bFirst) QE^$=\l0  
{ Gw}%{=D9  
nFileLength = getFileSize(); n<Z({\9&H  
if(nFileLength == -1) y*4=c_Z  
{ :vmH]{R  
System.err.println("File Length is not known!"); {j{u6i  
} 8o3E0k1  
else if(nFileLength == -2) NxkGOAOE  
{ ..IfP@  
System.err.println("File is not access!"); d2*fLEsF  
} X:A^<L ~  
else j_qbAP  
{ 4V{:uuI;f  
for(int i=0;i<nStartPos.length;i++) ~uj#4>3T  
{ ,1y@Z 5wy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {kA0z2Fe
 
} !44/sr'  
for(int i=0;i<nEndPos.length-1;i++) 6LvW?z(J  
{ Q)~aiI0  
nEndPos = nStartPos[i+1]; b:U$x20n$  
} .iYJr;9`d  
nEndPos[nEndPos.length-1] = nFileLength; @KXV%a'  
} BGvre'67  
} FI)17i$  
Uf1!qP/H?  
[zH:1Zhl&  
//启动子线程 ncZ+gzK|"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3OrczJ=[UF  
for(int i=0;i<nStartPos.length;i++) F8nYV  
{ >"??!|XG^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xipU8'ac/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Jz\%%C  
nStartPos,nEndPos,i); '*Z1tDFS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C(eTR1  
fileSplitterFetch.start(); a4mn*,  
} 4R#chQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?fQ'^agq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @bi}W`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BnX0G1|#  
nEndPos = " + nFileLength); S4Pxc ]!  
// fileSplitterFetch[nPos.length-1].start(); TYy?KG>:'  
eVEV}`X  
gt\E`HB8E  
//等待子线程结束 3$9s\<j  
//int count = 0; yks__ylrl(  
//是否结束while循环 q}b dx
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boolean breakWhile = false; "0V.V>-p  
y8d]9sX{  
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while(!bStop) )Oq|amvC  
{ 7LfAaj  
write_nPos(); 2Sle#nw3  
Utility.sleep(500); sZ3KT&  
breakWhile = true; S50k>_a;  
s,"]aew  
EB0TTJR?#  
for(int i=0;i<nStartPos.length;i++) ]RZ|u*l=x  
{ _F4Ii-6  
if(!fileSplitterFetch.bDownOver) Wjo[ENHM  
{ vt/x ,Y  
breakWhile = false; ZFiee|,q  
break; ](Xb_xMf  
} %@<8<6&q  
}
t*=CZE-  
if(breakWhile) EH-sZAv  
break; `jDTzhO~  
0
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%p Ynnfr  
//count++; RaO-H  
//if(count>4) MOQ6
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// siteStop(); ZFA`s qT  
} *2ZjE!A  
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9#23FK  
System.err.println("文件下载结束！"); Yc`o5Q\>  
} Fh)IgzFj  
catch(Exception e){e.printStackTrace ();} 0XOp3  
} -$t{>gO#Y  
^gN6/>]qrY  

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//获得文件长度 *zaQx+L  
public long getFileSize() $CRm3#+ ~  
{ <KJ/<0l  
int nFileLength = -1; ;/bewivNJ  
try{ ; 8_{e3s  
URL url = new URL(siteInfoBean.getSSiteURL()); LHyB3V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G?9"Y%  
httpConnection.setRequestProperty("User-Agent","NetFox"); _Ym]Mj' ln  
##q2mm:a9P  
q?Cnav`DY  
int responseCode=httpConnection.getResponseCode(); $5>e  
if(responseCode>=400) -<6\1J  
{ } j<)L,  
processErrorCode(responseCode); __uA}fZp  
return -2; //-2 represent access is error _,
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} /pm]BC  
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String sHeader; ?}qttj  
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for(int i=1;;i++) .nTwPrG  
{ \-L&5x"x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u^&A W$  
//Utility.log(in.readLine()); vjLJinJ/  
sHeader=httpConnection.getHeaderFieldKey(i); vp1941P  
if(sHeader!=null) Mc@
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{ 8."]//V  
if(sHeader.equals("Content-Length")) xP_cQwm`1  
{ a@8v^
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `Nv=B1  
break; w}L]X1#sF  
} Y2|#V#  
} 3s5z UT;  
else R
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break; C,wL0Yj[  
} 0;hqIJcE:\  
} >f^r^P  
catch(IOException e){e.printStackTrace ();} Y1L[;)Hn  
catch(Exception e){e.printStackTrace ();} Uq[>_"}  
uyO/55;HO  
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Utility.log(nFileLength); ``V" D  
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i1UiNJh86  
return nFileLength; Ha(c'\T(\  
} dW_KU}  
j >Ht@Wi  
Hfv7LM  
//保存下载信息（文件指针位置） Wfu(*  
private void write_nPos() =MSr/O2  
{ ]5mnew  
try{ Jlri*q"hE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'g6\CZw(#  
output.writeInt(nStartPos.length); t

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for(int i=0;i<nStartPos.length;i++) ,ly\Ka?zO  
{ =FlDb 5t{  
// output.writeLong(nPos); Z|%_&M  
output.writeLong(fileSplitterFetch.nStartPos); r~E=4oB7  
output.writeLong(fileSplitterFetch.nEndPos); Az9?Ra;U  
} Gp1?iX?ml  
output.close(); >c1!p]&V  
} R"4Vtww  
catch(IOException e){e.printStackTrace ();} 1=r#d-\tR  
catch(Exception e){e.printStackTrace ();} j@=%_^:i  
} R}
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 R(!s  
@V(*65b2  
//读取保存的下载信息（文件指针位置） B+Rm>^CBm  
private void read_nPos() y.anl  
{ I+BHstF5um  
try{ Bu#E9hJFvA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^({})T0wu  
int nCount = input.readInt(); %
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nStartPos = new long[nCount]; 3e #p@sB  
nEndPos = new long[nCount]; +:8fC$vVfC  
for(int i=0;i<nStartPos.length;i++) -mAUo;O  
{ >x/z7v?^I  
nStartPos = input.readLong(); Bs13^^hu
 
nEndPos = input.readLong(); SlgN&{Bk  
} l-fi%Z7C  
input.close(); 5k!g%sZ  
} *
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catch(IOException e){e.printStackTrace ();} 1uG"f<TsR  
catch(Exception e){e.printStackTrace ();} "&%I)e
^  
} 0+iu(VbF  
Y}x>t* I  
4^:\0UF  
private void processErrorCode(int nErrorCode) 00'%EYO  
{ :X0k]p  
System.err.println("Error Code : " + nErrorCode); %WSo b@f8  
} s&A} h  
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@"hb) 8ng  
//停止文件下载 (gEBOol  
public void siteStop() N<|@ymi  
{ kEJj=wx  
bStop = true; Mxe}B'  
for(int i=0;i<nStartPos.length;i++) 5
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fileSplitterFetch.splitterStop(); S-P/+K6  
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5}:-h>  
} 1j
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} /rMI"khB  
//负责部分文件的抓取 t'?.8}?)I&  
**FileSplitterFetch.java PjZvQ\Z  
*/ tU4s'J  
package NetFox; 3XL#0\im?s  
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import java.io.*; ^]7}YF2|  
import java.net.*; AZ0;3<FfLp  
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,X#2\r<|  
public class FileSplitterFetch extends Thread { 9G9fDG#F\I  
<nE>XAI_7  
`q?8A3A  
String sURL; //File URL j!_;1++q  
long nStartPos; //File Snippet Start Position H#NCi~M>3  
long nEndPos; //File Snippet End Position %4ePc-  
int nThreadID; //Thread's ID _  <WJ7  
boolean bDownOver = false; //Downing is over 2#P*,  
boolean bStop = false; //Stop identical 3wOZ4<B  
FileAccessI fileAccessI = null; //File Access interface Jzj1w}?H  
M1 :uJkO.  
b8~Bazk  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C3*gn}[  
{ \
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this.sURL = sURL; >[MX:Yh  
this.nStartPos = nStart; H
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this.nEndPos = nEnd; <%($7VMev  
nThreadID = id; "|Xk2U  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 os,* 3WO  
} }#.L7SIJ<J  
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kB3H="3[[  
public void run() m4aB*6<lq  
{ ~$ng^D  
while(nStartPos < nEndPos && !bStop) *vflscgt  
{ :QpuO1Gu  
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try{ ]gmexa=(i  
URL url = new URL(sURL); xgbJ2Mh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {kp
"nl$<  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9)}[7Mg:C  
String sProperty = "bytes="+nStartPos+"-"; pi /g H  
httpConnection.setRequestProperty("RANGE",sProperty); ]4~lYuI4  
Utility.log(sProperty); K#E
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InputStream input = httpConnection.getInputStream(); =G]1LTI  
//logResponseHead(httpConnection); FB
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_(Sa4Vb=Q6  
byte[] b = new byte[1024]; H
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int nRead; >*]Hq.&8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) WP?TX b`5  
{ M4zm,>?K  
nStartPos += fileAccessI.write(b,0,nRead); #,7e NM"  
//if(nThreadID == 1) #1`-*.u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >xF/Pl  
} #N#
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q  
v\!Be[ ?  
Utility.log("Thread " + nThreadID + " is over!"); Y]NSN-t  
bDownOver = true; \]&#%6|V  
//nPos = fileAccessI.write (b,0,nRead); qDv93  
} 4#ug]X4Y')  
catch(Exception e){e.printStackTrace ();} 8)O[Aq::  
} bu |a0h7e  
} ERpnuMb  
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T.@aep\"  
//打印回应的头信息 fG}tMSI  
public void logResponseHead(HttpURLConnection con) '$|[R98  
{ *+-}P|S:  
for(int i=1;;i++) X*&[u7No  
{ E_k$W5  
String header=con.getHeaderFieldKey(i); 'SCidN(n  
if(header!=null) ~Q?a|mV,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WOQP$D9  
Utility.log(header+" : "+con.getHeaderField(header)); Pf|siC^;s~  
else QrfG^GID  
break; 'qjeXqGH$  
} p89wNSMl[  
} {7$c8i  
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public void splitterStop() 3D`YZ#M  
{ zN!ZyI$nqP  
bStop = true; Q,p}:e  
} Db)?i?o}t  
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} ? i( %  
]Bm/eRy"  

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/* "iU}]e0  
**FileAccess.java >;L6xt3  
*//文件访问(定位，写) Gs9:6  
package NetFox; CPP` qt%f  
import java.io.*; nyBJb(5"B  
c/zJv*}x?  
kD*2~Z?;  
public class FileAccessI implements Serializable{ 5#> 8MU?&  
pV20oSJNt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T'4z=Z]w  
RandomAccessFile oSavedFile; *8#i$w11M  
long nPos; %1O;fQL  
p$
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_h X]%  
public FileAccessI() throws IOException ;cPy1  
{ @$LWWTr;  
this("",0); 5D_fXfx_|  
} ;\lW5ZX  
et,f_fd7v  
sYjpU  
public FileAccessI(String sName,long nPos) throws IOException iTag+G4*  
{ "kMguK}c  
oSavedFile = new RandomAccessFile(sName,"rw"); wm)#[x #  
this.nPos = nPos; b
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oSavedFile.seek(nPos); &K/ya7  
} qxFB%KqU  
TQx.KM>y  
IG|X!l  
public synchronized int write(byte[] b,int nStart,int nLen) o3I Tr';  
{ fRtUvC-#H  
int n = -1; O)ME"@r@:  
try{ 'h^0HE\~p  
oSavedFile.write(b,nStart,nLen); `FYv3w2  
n = nLen; XVKfl3'%  
} 5]HS^II"  
catch(IOException e) tZ^Ou89:rG  
{ @1DX  
e.printStackTrace (); 7PANtCFb&  
} 4g :>[q  
5e$~)
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return n; dl~%MWAVb  
} ?gJy3@D  
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} <Wp QbQM  
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/* `e(vH`VZ  
**SiteInfoBean.java Xlb0/T<g!  
*/ .Fnwm}  
package NetFox; mnmP<<8C,  
=$nB/K,8AX  
.G+Pe'4a  
public class SiteInfoBean { M@?xa/E64  
p;W.lcO`0  
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private String sSiteURL; //Site's URL kAu+zX>S+  
private String sFilePath; //Saved File's Path T}"6wywM  
private String sFileName; //Saved File's Name b@S Cn9  
private int nSplitter; //Count of Splited Downloading File
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mml<
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6(G?MW.  
public SiteInfoBean() %*&UJpbA  
{//nSplitter的缺省值为5 :{oZ~<  
//default value of nSplitter is 5 *e-A6Sh  
this("","","",5); emdoA:w+   
} IRn2|  
m< 3Ao^I+  
r8,romE$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nWMmna.5  
{ Kt"BE j  
sSiteURL= sURL; /\H>y  
sFilePath = sPath; LE*h9((  
sFileName = sName; aj?a^}X  
this.nSplitter = nSpiltter; 'JNElXqrv  
{W]=~*w  
]79:yMD~ba  
} Sp}tD<V  
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x-?{E
  
public String getSSiteURL() :PtF+{N>  
{ pp
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return sSiteURL; tUgEeh6  
} 2Sh  
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vP!{",>  
public void setSSiteURL(String value) ~M\I;8ne  
{ 7DIIx}
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sSiteURL = value; jLpc Zb,  
} de>v  
"R3d+p  
kI:}| _  
public String getSFilePath() qQ0cJIISb\  
{ \mV'mZ9>  
return sFilePath; 4E+hRKuo,  
} Op>%?W8/UF  
*P#WDXRwd  
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public void setSFilePath(String value) ^|TG$`M(w
 
{ xCYE B}o9r  
sFilePath = value; Gkp<o  
} dlG=Vq&Y  
jS]><rm  
=IUUeFv +r  
public String getSFileName() _>v<(7  
{ !>>f(t4  
return sFileName; .VkbYK  
} Dgx8\~(E'  
J]q%gcM  
8,atX+tc  
public void setSFileName(String value) r" K':O6y  
{ +]:2\TTGI  
sFileName = value; QO{y/{
 
} -V %gVI[  
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w>xV  
public int getNSplitter() ]+DI.%   
{ .w6eJ4]  
return nSplitter; O)R(==P26P  
} rC[6lIP  
:`vP}I ^  
 6qo^2  
public void setNSplitter(int nCount) >cL{Ya}Rz  
{ DZ ^1s~  
nSplitter = nCount; s]27l3)B  
} HjWq[[Nz  
} =wi*Nd7L  
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/* mT*{-n_Zs  
**Utility.java 4\ /*jA  
*/ G&eP5'B4i  
package NetFox; qu6DQ@ ~YC  
$trAC@3O@  
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public class Utility { w-N1.^  
@LD6:gy  
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public Utility() >n.z)ZJ  
{ m:Go-tk  
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(3,.3)%`  
} > ^[z3T  
|-2}j2'  
//线程睡眠 IF k  
public static void sleep(int nSecond) &217l2X /  
{ u3tZ[Y2 c  
try{ (9fdljl],:  
Thread.sleep(nSecond); a?cn9i)#  
} $<?X7n^  
catch(Exception e) VFD%h }  
{ KT*:F(4`  
e.printStackTrace (); X}4}&  
} nw'-`*'rj  
} CidM(  
eo#^L}  
//日志 #$'"cfRxc  
public static void log(String sMsg) j;P+_Hfe/E  
{
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System.err.println(sMsg); ^gro=Bp(  
} h=RDO  
nX%AeDBAT  
5a8>g [2U  
public static void log(int sMsg) \Xg?Ug*9w  
{ )+Or  
System.err.println(sMsg); Il~01|3+m  
} ('o&Q_  
} 2O""4_G  
M7y|EB))  
)xl6,bq3  
/* f!GHEhQ9  
**TestMethod.java F#q&(  
*/ "4}wnu6/  
package NetFox; zDBD.5R;  
:pKG\A  
o#i ]"  
public class TestMethod { nf%4sIQ*x  
|DG@ht  
]gd/}m)1  
public TestMethod() @] .VQ<X|0  
{ ///xx/weblogic60b2_win.exe -]"T^wib  
try{ 9fVj 8G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =q CF%~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D,W\ gP/h%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hFb fNB3  
fileFetch.start(); Z(!pYhLq  
} s^C;>  
catch(Exception e){e.printStackTrace ();} c]m! G'L_/  
F$6?t.@J  
eO4)|tW  
} !ng\` |8?  
j]> uZalr  
!;}2F
-  
public static void main(String[] args) P\B3 y+)  
{ LdTIR]  
new TestMethod(); ,?b78_,2  
} /mbCP>bcG  
} 5j[#'3TSU  
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