http断点续传简单实现（java)

/* AO0aOX8_+D  
**SiteFileFetch.java efm#:>H  
*/ iR4!X()  
package NetFox; gOn^}%4.I  
import java.io.*; 2L?Pw  
import java.net.*; OyTp^W`&  
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public class SiteFileFetch extends Thread { P!lTK
  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 /PtmJ2[  
long[] nEndPos; //结束位置 LF_am*F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8,&QY%8pX  
long nFileLength; //文件长度 PH]ui=  
boolean bFirst = true; //是否第一次取文件 r!O4]j_3  
boolean bStop = false; //停止标志 JJE0q5[  
File tmpFile; //文件下载的临时信息 Dq~D4
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DataOutputStream output; //输出到文件的输出流 !$.h[z^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <Z9N}wY,8  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ih5F\eM  
{ gX*i"Y#
 
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z<6Fq*I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  tvvRHvL  
if(tmpFile.exists ()) j?9fb  
{ agxR V  
bFirst = false; @P}!mdH1  
read_nPos(); EXTQ:HSES  
} &&{_T4  
else +G<9|-  
{ k6W [//  
nStartPos = new long[bean.getNSplitter()]; {w|KWGk2  
nEndPos = new long[bean.getNSplitter()]; \
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} Fwv(J_'q  
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} }@S''AA\  
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public void run() .jjvS  
{ dGBVkb4]T  
//获得文件长度 \Z%V)ZRi=  
//分割文件 ^N_?&pgy  
//实例FileSplitterFetch mBZg(TY  
//启动FileSplitterFetch线程 $f]dL};  
//等待子线程返回 l\{{iAC]I  
try{ KF4}cM=.5  
if(bFirst) p[lciWEW  
{ @G;\gJT*  
nFileLength = getFileSize(); &lYe  
if(nFileLength == -1) ^%r>f@h!L  
{
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System.err.println("File Length is not known!"); z^
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} -YHyJs-bU  
else if(nFileLength == -2) \a}W{e=FNT  
{ |ydOi&  
System.err.println("File is not access!"); H%AC *,  
} UjI-<|  
else ^6U0n!nU  
{ C%y!)v_x  
for(int i=0;i<nStartPos.length;i++) ;3H#8x-  
{ RRH[$jk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZhpbbS  
} 5*W<6ia  
for(int i=0;i<nEndPos.length-1;i++) l /\n7:  
{ $-:j'e:j  
nEndPos = nStartPos[i+1]; /Sag_[i  
} J(JqusQd !  
nEndPos[nEndPos.length-1] = nFileLength; 8S_v} NUm  
} -h/KrB  
} AT%@T|  
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//启动子线程 atA:v3"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v!
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for(int i=0;i<nStartPos.length;i++) ,B=;NKo  
{ C_JDQByfL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w0FkKJV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gZD,#D.hR  
nStartPos,nEndPos,i); oI6l`K$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {tlt5p!4  
fileSplitterFetch.start(); C3p/|{TP  
} LT ZoO9O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jZ8#86/#{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b\l +S2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .;&1"b8G  
nEndPos = " + nFileLength); Jm l4EW7  
// fileSplitterFetch[nPos.length-1].start(); JNYFu0  
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e+t2F |xDh  
//等待子线程结束 C=z7Gk=  
//int count = 0; ,?Bo x  
//是否结束while循环 +%hA6n  
boolean breakWhile = false; eviv,  
-`
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while(!bStop) RI q9wD}4(  
{ )+nY-DB(  
write_nPos(); .Y"H{|]Mnh  
Utility.sleep(500); 'L"dM9#>  
breakWhile = true; '<35XjW  
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for(int i=0;i<nStartPos.length;i++) *Hnk,?kPq  
{ xgi/,Nk '  
if(!fileSplitterFetch.bDownOver) `6.rTs$<  
{ _FET$$>z N  
breakWhile = false; G:]w UC\  
break; CqRG !J  
} Q599@5aS  
} 8p?Fql}F[  
if(breakWhile)
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break; \Ami-<T  
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//count++; wi]F\ q"Y^  
//if(count>4) _IA@X. )?  
// siteStop(); /idQfff  
} ctv=8SFv(  
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System.err.println("文件下载结束！"); ^b{w\HZ  
} F0O/SI(cA  
catch(Exception e){e.printStackTrace ();} JO4rU- n  
} uIG,2u,  
wz-#kH5?  
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//获得文件长度 '\$2+*  
public long getFileSize() [dK
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{ V Q6&7@ c  
int nFileLength = -1; H0zKL]D'>  
try{ p*T`fOL  
URL url = new URL(siteInfoBean.getSSiteURL()); hcvWf\4'#q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~mqiXr8  
httpConnection.setRequestProperty("User-Agent","NetFox"); U{2[nF  
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int responseCode=httpConnection.getResponseCode(); TNA?fm  
if(responseCode>=400) ^6*2a(S&  
{ D0(%{S^  
processErrorCode(responseCode); pq 4/>WzE  
return -2; //-2 represent access is error n5Ad@Bg  
} LRqBP|bjCD  
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String sHeader; n+Ia@$|m  
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}n+#o!uEf  
for(int i=1;;i++) H'f
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{ "v @h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <1HbjRw  
//Utility.log(in.readLine()); 8Bvc#+
B  
sHeader=httpConnection.getHeaderFieldKey(i); ,)u\G(N  
if(sHeader!=null) ggr\n
Y  
{ gpBpG  
if(sHeader.equals("Content-Length")) GA,6G [E  
{ jG"n);WF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R<}n?f\#JZ  
break; .w/_Om4T*b  
} 1epj/bB&  
} 3cuVyf<v  
else |K(j}^1k  
break; l$ABOtM@  
} $"z|^ze  
} kW"6Gc&HUN  
catch(IOException e){e.printStackTrace ();} -!OFt}  
catch(Exception e){e.printStackTrace ();} Ccmo(W+0  
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Utility.log(nFileLength); Yx4TUA$c'  
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return nFileLength; | |=q"h3(  
} /&g5f4[|p  
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//保存下载信息（文件指针位置） ys+ AY^/  
private void write_nPos() 8lAs~c  
{ 1]wx Ru  
try{ V87?J w%2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ][b_l(r$?  
output.writeInt(nStartPos.length);  xZJ r
*  
for(int i=0;i<nStartPos.length;i++) Tx)X\&ij&  
{ @D<q=:k  
// output.writeLong(nPos); F!FXZht$P  
output.writeLong(fileSplitterFetch.nStartPos); %E\&9,  
output.writeLong(fileSplitterFetch.nEndPos); r;gtfX*  
} *#O8 ^3D_c  
output.close(); t{\,vI  
} {U:c95#.!S  
catch(IOException e){e.printStackTrace ();} 7Sc._G{[%  
catch(Exception e){e.printStackTrace ();} Y|eB;D
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} [yzDa:%  
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//读取保存的下载信息（文件指针位置） Y7QIFY's~  
private void read_nPos() fv1pA+zN[  
{ H
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try{ F$l]#G.@A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1 J3h_z6/  
int nCount = input.readInt(); uWs5+  
nStartPos = new long[nCount]; k5]M~"  
nEndPos = new long[nCount]; 9mdp\A  
for(int i=0;i<nStartPos.length;i++) _wa1R+`_  
{ ^a=,,6T  
nStartPos = input.readLong(); !!NVx\a  
nEndPos = input.readLong(); dl:uI5]  
} x1\a_Kt  
input.close(); P<AN`un  
} 'g<0MOq{  
catch(IOException e){e.printStackTrace ();} J(CqT/Au-  
catch(Exception e){e.printStackTrace ();} 3*13XQ  
} }R.<\  
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private void processErrorCode(int nErrorCode) Vz$X0C=W;H  
{ N7A/&~g5L  
System.err.println("Error Code : " + nErrorCode); =d#3& R]p  
} ekB
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9v_B$F$_T  
^j1?LB  
//停止文件下载 XWQp-H.  
public void siteStop() <mE)&7C  
{ ;x.xj/7  
bStop = true; %M+ID['K9/  
for(int i=0;i<nStartPos.length;i++) E|!rapa  
fileSplitterFetch.splitterStop(); wgm?lfX<  
1-.UkdZ}  
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} ") Xy%C`J  
} Y|bCbaF  
//负责部分文件的抓取 chE~UQ  
**FileSplitterFetch.java w!{g^*R+!  
*/ fL[(;KcAa  
package NetFox; j(Tt-a("z  
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import java.io.*; gie}k)&M  
import java.net.*; /6_>d$  
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public class FileSplitterFetch extends Thread { q5il9*)d(  
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String sURL; //File URL Hd(|fc{2  
long nStartPos; //File Snippet Start Position 3cK`RM `  
long nEndPos; //File Snippet End Position Z/=x(I0  
int nThreadID; //Thread's ID /`yb75  
boolean bDownOver = false; //Downing is over ]m0MbA  
boolean bStop = false; //Stop identical eup#.#J  
FileAccessI fileAccessI = null; //File Access interface ax7]>Z=%d"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q|)
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{ 7o?6Pv%HJC  
this.sURL = sURL; U[5  
this.nStartPos = nStart; \&
6  
this.nEndPos = nEnd; 3DRXao  
nThreadID = id; c!@g<<}[(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |n-NK&Y(o  
} "i$Avm  
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public void run() =VkbymIZ4y  
{ BR5r
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while(nStartPos < nEndPos && !bStop) @;m7u
  
{ [4,=%ez  
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try{ m_~!Lj[u.  
URL url = new URL(sURL); X)iQ){21V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pv%UsbY  
httpConnection.setRequestProperty("User-Agent","NetFox"); f1F#U@U  
String sProperty = "bytes="+nStartPos+"-"; j["b*X`8G  
httpConnection.setRequestProperty("RANGE",sProperty); $fSV8n;Y  
Utility.log(sProperty); `mV&[`NZ  
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InputStream input = httpConnection.getInputStream(); hR"j[  
//logResponseHead(httpConnection); d*ch.((-  
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byte[] b = new byte[1024]; ?<c)r~9]  
int nRead; E[bJ5o**#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1t{h)fwi  
{ E/9h"zowS  
nStartPos += fileAccessI.write(b,0,nRead); .XR`iXY  
//if(nThreadID == 1) Rk8>Ak(/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zk8s?$  
} Ht,_<zP;  
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Utility.log("Thread " + nThreadID + " is over!"); [r%WVf.#d  
bDownOver = true; 6tXx--Nh  
//nPos = fileAccessI.write (b,0,nRead); Hm@+(j(N96  
} /*J}7  
catch(Exception e){e.printStackTrace ();} CHp`4  
} =E@wi?  
} 1qXqQA  
rjfcZ@  
*het_;)+{  
//打印回应的头信息 CYA#:  
public void logResponseHead(HttpURLConnection con) J+IQvOn_|  
{ WvVHSa4{  
for(int i=1;;i++) =qH9<,p`H  
{ ,Oojh;P_  
String header=con.getHeaderFieldKey(i); =)}m4,LA  
if(header!=null) rug^_d=B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pE(\q+1<  
Utility.log(header+" : "+con.getHeaderField(header)); |r*btyOJk  
else DIO @Zo  
break; rJi;"xF8  
} J9J[.6k8  
} 
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public void splitterStop() FtbqZN[  
{ N\XZ=t^h(  
bStop = true; V {R<R2
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}  |/K+tH  
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} QF:">G  
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/* hYRGIpu5  
**FileAccess.java zh7#[#>t  
*//文件访问(定位，写) - Z?rx5V;t  
package NetFox; j3 d=O!  
import java.io.*; seWYY $$  
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public class FileAccessI implements Serializable{ Ep-{Ew{T_=  
ZM"J5}h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }5dYmny  
RandomAccessFile oSavedFile; Isv@V.  
long nPos; <]I[|4J 7  
"<b~pfCOQk  
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public FileAccessI() throws IOException -DDH)VO  
{ `[\*1GpAo  
this("",0); b}'XDw   
} w :2@@)pr  

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public FileAccessI(String sName,long nPos) throws IOException S N_!o2F2  
{ VgG*y#Qf$  
oSavedFile = new RandomAccessFile(sName,"rw"); g+8{{o=  
this.nPos = nPos; @2Xw17[f35  
oSavedFile.seek(nPos); l +RT>jAmK  
} 7m0sF<P{g  
[B3qZ"  
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public synchronized int write(byte[] b,int nStart,int nLen) shjbb  
{ w^tNYN,i  
int n = -1; }8cL+JJU  
try{ |0YDCMq(  
oSavedFile.write(b,nStart,nLen); j3|Ek  
n = nLen; 'J~{8w,.  
} s>d@=P>R  
catch(IOException e) {IEc{y7?gO  
{ [?uiM^&  
e.printStackTrace (); td-2
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} \/,54c2  
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return n; @? 4-  
} z7'3d7r?  
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} A-<\?13uW  
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/* ec
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**SiteInfoBean.java )70-q yA  
*/ Cv{>|
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package NetFox; N{v <z 6  
i-Ck:-J  
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public class SiteInfoBean { %rVC3}  
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3]DUUXg$  
private String sSiteURL; //Site's URL R,[dEP  
private String sFilePath; //Saved File's Path xab1`~%K  
private String sFileName; //Saved File's Name E O^j,x g  
private int nSplitter; //Count of Splited Downloading File +{Yd\{9  
_r+2o-ZR  
cLl=?^DB  
public SiteInfoBean() t_1(Ex  
{//nSplitter的缺省值为5 5X>b(`  
//default value of nSplitter is 5 s0,c4y  
this("","","",5); /IS_-h7>XS  
} 4'JuK{/ A7  
p^PAbCP'|3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Vg9nb  
{ =\]5C  
sSiteURL= sURL; SYkLia(Ty  
sFilePath = sPath; 0LX;Vvo  
sFileName = sName; 5tUp[/]pl  
this.nSplitter = nSpiltter; S*,DX~vig  
`j+aAxJ=\  
{RFpTh7f:  
} tow0/Jt  
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public String getSSiteURL() Gs^hqT;h  
{ e7X#C)  
return sSiteURL; x {Z_rD  
} OxGKtnAjf  
f5p>oXo4b  
:u$nH9kwv  
public void setSSiteURL(String value) -Lh\]  
{ .bcoH  
sSiteURL = value; H+Dv-*i  
} NN(ZH73  
nT.i|(xd.  
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public String getSFilePath()
'%U'%')  
{ :&*Y Io  
return sFilePath; _XLGX
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} N<&"_jzm  
CJ+/j=i;~c  
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public void setSFilePath(String value) L9(mY `d>"  
{ 88%7  
sFilePath = value; Cq mtO?vne  
} oSd TQ$U!D  
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public String getSFileName() 8%C7!l q  
{ bs_>!H1  
return sFileName; 7 YS'Tf  
} b,vSE,&xP  
4yOYw*X  
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public void setSFileName(String value) m/ D~D~  
{ [4p~iGC  
sFileName = value; Vf28R,~m  
} Bi}uL)~rD  
B49: R>  
9]u=b\fzZ  
public int getNSplitter() &6ymGo  
{ o[$~  
return nSplitter; +Cf"rN  
} 6}z-X*  
b'x26wT?  
AvP$>Alc  
public void setNSplitter(int nCount) &m{SWV+  
{ /\7E&n:)2  
nSplitter = nCount; nZtMF%j'  
} AW{"9f4  
} 6&8uLM(z  
+(Q$GO%  
:mYVHLmea  
/* <8J_[ S  
**Utility.java k
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*/ 0H9UM*O  
package NetFox; qdW"g$fW  
+aY]?]  
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public class Utility { P/!W']OO  
;?h+8Z/{  
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public Utility() Ji#eA[  
{ OrC}WMhd  
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} {s7 3(B"  
W(#u^,$e[  
//线程睡眠 4*U5o!w1{  
public static void sleep(int nSecond) FF5|qCV/z  
{ C0K0c6A(4  
try{  `1`Qu!  
Thread.sleep(nSecond); aPToP.e  
} Tr@|QNu  
catch(Exception e) 7Gwo:s L  
{ %&iodo,EP'  
e.printStackTrace (); zG* >g  
} :pH
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} 0h-'TJg*sk  
f1$'av
 
//日志 >vPv4e7&3  
public static void log(String sMsg) koojF|H>  
{ # 4&t09  
System.err.println(sMsg); goqm6
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} e"(SlR  
dW5@Z-9  
=]fOQN`  
public static void log(int sMsg) d-cW47  
{ @|PUet_pb  
System.err.println(sMsg); Zmc"  
} Gk']Ma2J}  
} ;#?G2AAv  
dQs>=(|t  
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/* j  Gp&P  
**TestMethod.java ^M)+2@6  
*/ LC,6hpmh  
package NetFox; $
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.% 79(r^  
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public class TestMethod { u[
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public TestMethod() 8#nAs\^  
{ ///xx/weblogic60b2_win.exe 34,'smHi%  
try{ M`&78j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); USg,=YM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J=J!)\m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dsn(h5,Q'  
fileFetch.start(); 25j?0P"&  
} )UtK9;@"  
catch(Exception e){e.printStackTrace ();} j+PLtE  
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"/ySHB[  
} AqAL)`#K  
Zb7%$1)L~  
3a[LM!  
public static void main(String[] args) 9PUobV_^Wo  
{ G{!(2D4!  
new TestMethod(); }9 ]7V<  
} }}Zg/(  
} {
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