http断点续传简单实现（java)

/* c813NHW  
**SiteFileFetch.java ozl!vf# kv  
*/ R(cg`8  
package NetFox; .c__T{<)[  
import java.io.*; 5ddfdIp  
import java.net.*; S'NLj(  
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public class SiteFileFetch extends Thread { V d]7v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?.lo[X<,*  
long[] nStartPos; //开始位置 DBLM0*B  
long[] nEndPos; //结束位置 IXR'JZ?f
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 'RzO`-dr  
long nFileLength; //文件长度 u=vBjaN2_w  
boolean bFirst = true; //是否第一次取文件 bQwG"N  
boolean bStop = false; //停止标志 E'(nJ  
File tmpFile; //文件下载的临时信息 BF;}9QebmS  
DataOutputStream output; //输出到文件的输出流 /;1O9HJa  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） SBDGms  
public SiteFileFetch(SiteInfoBean bean) throws IOException FH$q,BI!R  
{ U|\ .)h=  
siteInfoBean = bean; 6KXW]a `  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i?uX'apk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B I3fk  
if(tmpFile.exists ()) <hTHY
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{ #M+_Lk3  
bFirst = false; PB5h5eX  
read_nPos(); .]JIo&>5  
} H270)Cwn+  
else k*\)z\f  
{ 4gNN "  
nStartPos = new long[bean.getNSplitter()]; J]{<Z?%  
nEndPos = new long[bean.getNSplitter()]; :M f8q!Q'  
} -o{ x ;:4  
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} hiA\~}sl n  
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public void run() ED" fi$  
{ XuHR  
//获得文件长度 I.T?A9Z  
//分割文件 v-q-CI?B#  
//实例FileSplitterFetch 6akI5\b  
//启动FileSplitterFetch线程 "19#{yX4  
//等待子线程返回 *FZav2]-  
try{ lz36;Fp  
if(bFirst) 8~s0%%{,M  
{ |0}7/^  
nFileLength = getFileSize(); WVOj;c  
if(nFileLength == -1) d!Gy#<H  
{ ]7yxXg  
System.err.println("File Length is not known!"); 3(,m(+J[S  
} tY!l}:E[  
else if(nFileLength == -2) udBIEW,`  
{ J[hmY=,  
System.err.println("File is not access!"); 'g'RXC}D>  
} c_M[>#`  
else jWi~Q o+  
{ BmccSC;o4  
for(int i=0;i<nStartPos.length;i++) : xg
go  
{ x|dP-E41\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qBh@^GxY),  
} o$+R
  
for(int i=0;i<nEndPos.length-1;i++) -1v9  
{ &ni#(  
nEndPos = nStartPos[i+1]; 6DK).|@$r  
} ^,AE;ZT7  
nEndPos[nEndPos.length-1] = nFileLength; Q@>1z*'I  
} Iz.

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} cg17e  
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?~t5>PEonv  
//启动子线程 <g;,or#$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e!gNd>b {  
for(int i=0;i<nStartPos.length;i++) {f)aFGp  
{ Kl%[fjI)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wCR! bZ w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), SOM? 0.  
nStartPos,nEndPos,i); T#E$sZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YGLq
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fileSplitterFetch.start(); k3@d =k  
} i$@xb_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D6&P9e_5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jl(D;JnF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E QU@';~8  
nEndPos = " + nFileLength); UXdc'i g  
// fileSplitterFetch[nPos.length-1].start(); Qj_)^3`e  
x>TIx[x  
L[Z^4l_!  
//等待子线程结束 c$2kR:  
//int count = 0; .ve_If-Hg  
//是否结束while循环 ]w _&%mB  
boolean breakWhile = false; I]+ zG  
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while(!bStop) W)/f5[L  
{ 8~R.iqLoX  
write_nPos(); e@0|fB%2  
Utility.sleep(500); Q[K$f%>  
breakWhile = true; :f39)g5>  
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for(int i=0;i<nStartPos.length;i++) .d^8?vo  
{ 7qO
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if(!fileSplitterFetch.bDownOver) _BerHoQd  
{ g|?}a]G  
breakWhile = false; %%?}db1n  
break; 0|tyKP|J  
} |UWIV  
} eZ]r"_?  
if(breakWhile) ]1d)jWG  
break; _BJ:GDz>  
% R25, V  
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//count++; P![ZO6`:W'  
//if(count>4) gL&w:_  
// siteStop(); Tc||96%2^  
} V61oK  
.[]S!@+%  
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System.err.println("文件下载结束！");  ArAe=m!u  
} @YH>|{S&  
catch(Exception e){e.printStackTrace ();} 4_j_!QH87  
}  ov,  
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//获得文件长度 .`+~mQ Wn  
public long getFileSize() 6:B,ir _  
{ ]J!#"m-]  
int nFileLength = -1; Qu=b
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try{ }(Fmr7%m  
URL url = new URL(siteInfoBean.getSSiteURL()); =CD6x= l6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U+B"$yBR  
httpConnection.setRequestProperty("User-Agent","NetFox"); *k,3@_5  
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int responseCode=httpConnection.getResponseCode(); 9D=X3{be#  
if(responseCode>=400) |mn} wNUN]  
{ ri59LYy=  
processErrorCode(responseCode); *kK +Nvt8s  
return -2; //-2 represent access is error l9eTghLi  
} .U|'KCM9m  
9(S=0<  
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String sHeader; H@wjZ;R  
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for(int i=1;;i++) gsM$VaF(  
{ ]f&]E ~i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K3 BWj33  
//Utility.log(in.readLine()); %pOz%v~  
sHeader=httpConnection.getHeaderFieldKey(i); SWI\;:k  
if(sHeader!=null) 1<#D3CXK  
{  gvo98Id  
if(sHeader.equals("Content-Length")) NR_3
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{ 2D"my]FnF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `V V>AA5  
break; iz/CC V L  
} *'aJO}$  
} +,)k@OI  
else >m1b/J3#  
break; "A~dt5GJ  
} FO_}9<s  
} z5iC
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catch(IOException e){e.printStackTrace ();} lN5PKsGl  
catch(Exception e){e.printStackTrace ();} i7h^L)M  
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Utility.log(nFileLength); p7`9 d1n  
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return nFileLength; l}^ziY!  
} =#9#unvE!  
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}#e=*8F7  
//保存下载信息（文件指针位置） _^b\#Jz4U3  
private void write_nPos() ]O:8o<0  
{ |-\anby<  
try{ 2RNee@!JJP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p2b~k[  
output.writeInt(nStartPos.length); <#M1I!R  
for(int i=0;i<nStartPos.length;i++) Y&=DjKoVh  
{ a9NuYYr,h  
// output.writeLong(nPos); <BBzv-?D  
output.writeLong(fileSplitterFetch.nStartPos); lc5(^~  
output.writeLong(fileSplitterFetch.nEndPos); Pz2Q]}(w  
} b1IAp>*2l  
output.close(); ]JGq{I>%+6  
} m)<+?Bv y  
catch(IOException e){e.printStackTrace ();} ~s'}_5;VY  
catch(Exception e){e.printStackTrace ();} aDX&j2/  
} dPpQCxf  
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`fEzE\\!*  
//读取保存的下载信息（文件指针位置） [
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private void read_nPos() JLWm9c+UTG  
{ zJ8T.+qJ  
try{ dT7fyn  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~1*37w~  
int nCount = input.readInt(); 4>L*7i  
nStartPos = new long[nCount]; #M w70@6  
nEndPos = new long[nCount]; r]\[G6mE%  
for(int i=0;i<nStartPos.length;i++) ) aMiT  
{ Fng  
nStartPos = input.readLong(); -;"A\2_y  
nEndPos = input.readLong(); N@<-R<s^  
} ;2g.X(Ra  
input.close(); sXP
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} >ZPu$=[W  
catch(IOException e){e.printStackTrace ();} [Nm?qY  
catch(Exception e){e.printStackTrace ();} 4x+[?fw  
} kkHK~(>G  
[vb#W!M&|  
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private void processErrorCode(int nErrorCode) o?M;f\Fy  
{ ;t9_*)[  
System.err.println("Error Code : " + nErrorCode); Y}.f&rLe  
} oaq,4
FT  
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}I}GA:~$%  
//停止文件下载 {GCp5  
public void siteStop() hTv*4J&@|  
{ .tfal9  
bStop = true; Ex_dqko  
for(int i=0;i<nStartPos.length;i++) A~>B?Wijqg  
fileSplitterFetch.splitterStop(); ?rt[ aK  
z)*{bz]  
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} 0)K~pV0aT  
} NF |[j=?  
//负责部分文件的抓取 4,QA {v  
**FileSplitterFetch.java yCkc3s|DA;  
*/ -9+$z|K  
package NetFox; e&ZTRgYdi  
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2,I]H'}^  
import java.io.*; kl1Q:  
import java.net.*; {GT5   
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public class FileSplitterFetch extends Thread { 'cS| BT  
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|)jR|8MAE  
String sURL; //File URL P>~Usuf4  
long nStartPos; //File Snippet Start Position @Bkg<  
long nEndPos; //File Snippet End Position yF|yZ{  
int nThreadID; //Thread's ID U_aI!`WXd  
boolean bDownOver = false; //Downing is over q%A>q;l:  
boolean bStop = false; //Stop identical $1s>efP-  
FileAccessI fileAccessI = null; //File Access interface Rd;t}E$  
/u]#dX5  
=$^}"}$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M54czo=l  
{ ~LFM,@  
this.sURL = sURL; L*6<h  
this.nStartPos = nStart; 438r]f?0|{  
this.nEndPos = nEnd;  C.uv
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nThreadID = id; Jk|DWZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A -8]4p::  
} r_bG+iw7p  
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public void run() 4C:dkaDq]  
{ {4[
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while(nStartPos < nEndPos && !bStop) N@'l:N'f4  
{ 'MyJw*%b]  
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try{ X>yE<ni  
URL url = new URL(sURL); TOP,]N/F H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z!'kN\z  
httpConnection.setRequestProperty("User-Agent","NetFox"); $OGMw+$C^  
String sProperty = "bytes="+nStartPos+"-";  +
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httpConnection.setRequestProperty("RANGE",sProperty); r}|)oG,=  
Utility.log(sProperty); ?6N
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InputStream input = httpConnection.getInputStream(); p ~+sk1[.  
//logResponseHead(httpConnection); l% %cU"  
7:$dl#  
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byte[] b = new byte[1024]; trLxg H_Y  
int nRead; #t# S(A9)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ecvZwL  
{ 9/&1lFKJ  
nStartPos += fileAccessI.write(b,0,nRead); RJT55Rv{  
//if(nThreadID == 1) m^/>C-&C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *z~
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} 4 #lLC-k  
y^{4}^u-^  
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Utility.log("Thread " + nThreadID + " is over!"); 5(Q-||J  
bDownOver = true; FS?1O"_  
//nPos = fileAccessI.write (b,0,nRead); Skux&'N:  
} %A&g-4(  
catch(Exception e){e.printStackTrace ();} <x$fD37  
} C<^S$  
} b3GTsX\2|  
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^b.fci{1m  
//打印回应的头信息 <X97W\  
public void logResponseHead(HttpURLConnection con) 4h}\Kl  
{ IL*MB;0>  
for(int i=1;;i++) J04R,B  
{ \naG  
String header=con.getHeaderFieldKey(i); :2{ [f+  
if(header!=null) V*6
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 98{n6$\  
Utility.log(header+" : "+con.getHeaderField(header)); GapH^trm  
else t3Iij0b~  
break; 6p,}?6^  
} Fk`6 q
 
} :}v:=ck  
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public void splitterStop() GsqO^SV  
{ $VxuaOTyVZ  
bStop = true; aJ]t1  
} ^#7&R"  
q| *nd!y'  
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} T?-K}PUcQ  
; Oz p  
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/* Hu!<GB~  
**FileAccess.java B=%YD"FAv  
*//文件访问(定位，写) N,cj[6;T%  
package NetFox; n2(\pQKm  
import java.io.*; =G rg  
2 t]=-@  
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public class FileAccessI implements Serializable{ 34vH+,!u  
-r{]9v2j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lWU? R  
RandomAccessFile oSavedFile; wmX *n'l  
long nPos; Pv8AWQQJ  
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public FileAccessI() throws IOException .ityudT<  
{ &gvX<X4e  
this("",0); mgEZiAV?  
} =Ajw(I[56  
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public FileAccessI(String sName,long nPos) throws IOException t\<*Q3rl-  
{ Fw"x
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oSavedFile = new RandomAccessFile(sName,"rw"); 7I6&*I  
this.nPos = nPos; pkA(\0E8  
oSavedFile.seek(nPos); W4AFa>h  
} G9> 0w)r  
`XbV*{7  
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public synchronized int write(byte[] b,int nStart,int nLen) :UsNiR=l  
{ 8DlRD$_:&  
int n = -1; sVIw'W  
try{ \OF"hPq  
oSavedFile.write(b,nStart,nLen); 2wZyUB;  
n = nLen; !2]G.|5/A  
} s.@DI|Gnf  
catch(IOException e) Cx`?}A\%  
{ &e
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e.printStackTrace (); }Q>??~mVl
 
} 3ry0.  
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return n; zDA;FKZPp  
} ,W;2A0A?X  
/=:X,^"P  
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} j}DG +M  
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/* rIF6^?  
**SiteInfoBean.java \RyW#[(  
*/ vC!}%sxVw_  
package NetFox; 'd=B{7k@  
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public class SiteInfoBean { 2UjQ!g`  
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k:kx=K5=4  
private String sSiteURL; //Site's URL ^0&   
private String sFilePath; //Saved File's Path Ea[K$NC)#  
private String sFileName; //Saved File's Name o8ADAU"  
private int nSplitter; //Count of Splited Downloading File GbZqLZ0  
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public SiteInfoBean() FOd)zU*L2  
{//nSplitter的缺省值为5 =P<7tsSuoK  
//default value of nSplitter is 5 &p#.m"Oon  
this("","","",5); N[AX]gOJ  
} [CJr8Qn  
41jx+ 0\Z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RI jz7ZG  
{ -XtDGNHF  
sSiteURL= sURL; ,XNz.+Ov  
sFilePath = sPath; ue{0X\[P<  
sFileName = sName; VKp
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this.nSplitter = nSpiltter; G4eY}3F7,4  
&'-ze,k}  
t#6@~49  
} D^9r#&  
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-*Z;EA-  
public String getSSiteURL() ht%:e?@i  
{ %JC-%TRWK  
return sSiteURL; %$L!N-U6  
} d@-bt s&3  
0(!D1G{ul  
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public void setSSiteURL(String value) A296f(  
{ VdV18-ea  
sSiteURL = value; >|22%YVX  
} UFy"hJchO  
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public String getSFilePath() (},TZ+u
 
{ X!%C
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return sFilePath; 4:p+C-gs  
} |+Fko8-  
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public void setSFilePath(String value) w(KB=lA2  
{ WS?"OTH.^\  
sFilePath = value; Hjm  
} co$I htOv  
{@c)!%2$  
8QN#PaY  
public String getSFileName() =)GhrWeVi4  
{ m:,S1V_jl  
return sFileName; t Tky  
} ErNL^Se1  
|i7j}i  
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public void setSFileName(String value) 2Po e-=  
{ " E U[Lb  
sFileName = value; 8f37o/L  
} QFm~wv8:  
q;p:)Q"  
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public int getNSplitter() b]Xc5Dp{  
{ ny:4L{)  
return nSplitter; 7]w]i5  
} -5~&A6+ILn  
}x^q?;7xW  
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public void setNSplitter(int nCount) Rh:edQ#  
{  <
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nSplitter = nCount; Rs0O4.yi;@  
} jF}u%T)HL  
} CnT]uU  
t`6R)'  
VuqJ&U.-  
/* z+>FKAF  
**Utility.java b3z{FP  
*/ 9K\A4F}  
package NetFox; CXr]V"X9  
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public class Utility { 0T{Z'3^=  
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public Utility() ]D@_cxud3  
{ 8%
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`J%iFm/5*  
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} 1/O7KR`K  
tiI:yq0  
//线程睡眠 $d]3ek/  
public static void sleep(int nSecond) +5|wd6  
{
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try{ bF5mCR:  
Thread.sleep(nSecond); #-wtNM%1#  
} l0^~0xlED  
catch(Exception e) Gy+/P6  
{ Gf(|?" H  
e.printStackTrace (); iB
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} '+6Sk
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} p_x@FA(  
nwOT%@nw  
//日志 ai!zb2j!E  
public static void log(String sMsg) ~|_s2T  
{ U8+5{,$\.  
System.err.println(sMsg); {G:dhi  
} lLq:(zMH  
o& g01t  
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public static void log(int sMsg) vR X_}`m8#  
{ 0=3Av8  
System.err.println(sMsg); 5E|y5|8fb  
} 2UPqn#.3  
} 6  XZF8W  
nU{}R"|  
3dlL?+Y#  
/* }IM*Vsk  
**TestMethod.java \t6k(5J  
*/ tnv @`xBn  
package NetFox; 8[zux4<m  
8<gYB$* S  
:T62_cFG  
public class TestMethod { ?pS,?>J f  
sEQAC9M  
#bz#&vt$  
public TestMethod() jA&ZO>4  
{ ///xx/weblogic60b2_win.exe 3oH.1M/  
try{ T}%8Vlt]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qy>n]->%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N,Fmu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z2HH&3HA  
fileFetch.start(); eI%{/>  
} MGt[zLF9  
catch(Exception e){e.printStackTrace ();} ^Jv$Wx  
p~/  
;7jszs.6%  
} }Zs y&K  
rHzwSR@}1  
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public static void main(String[] args) z}'-gv\,  
{ %XX(x'^4  
new TestMethod(); ~N<zv({lG  
} 5crd.1@^  
} 0X.(BRI~6p  
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