http断点续传简单实现（java)

/* 7cJh
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**SiteFileFetch.java ",qJG]_ <  
*/ OAXF=V F#  
package NetFox; vtVc^j4  
import java.io.*; b^]@8I[M  
import java.net.*; /DBldL7
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public class SiteFileFetch extends Thread { !q_fcd^c
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^w|apI~HSE  
long[] nStartPos; //开始位置 c/G]r|k  
long[] nEndPos; //结束位置 Y^@Nvt$<K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1WW`%  
long nFileLength; //文件长度 Fxr$j\bm  
boolean bFirst = true; //是否第一次取文件 D27MT/=7  
boolean bStop = false; //停止标志 =Wj{J.7mf]  
File tmpFile; //文件下载的临时信息 >'X[*:Cx  
DataOutputStream output; //输出到文件的输出流 9xm'0 '  
 <c&6M  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Zr.6J*&!  
public SiteFileFetch(SiteInfoBean bean) throws IOException `upxM0gc  
{ <..|:0Q&~  
siteInfoBean = bean; 1v^eXvY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \E<t'\>@X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [10;Mg  
if(tmpFile.exists ()) UI>?"b6 L  
{ uY6|LTK&x  
bFirst = false; APA:K9jD  
read_nPos(); ;<=B I!  
} ~'9>jpnw  
else  1ZF>e`t8  
{ \.%GgTF  
nStartPos = new long[bean.getNSplitter()]; Ce0YO~I  
nEndPos = new long[bean.getNSplitter()]; *U=%W4?W  
} ~Z#jIG<?g  
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} V 2WcPI^  
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public void run() ;{k`nv_6  
{ G*;6cV19  
//获得文件长度 eJ23$VM+9  
//分割文件 Cg!]x o  
//实例FileSplitterFetch h NCoX*icd  
//启动FileSplitterFetch线程 A#6\5u  
//等待子线程返回 "me a*-XB  
try{ f2"
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if(bFirst) tM$w0Cj  
{ Mh+ym]6\(k  
nFileLength = getFileSize(); kr|u ||  
if(nFileLength == -1) jo_wBJKE  
{ GrB+Y!{{  
System.err.println("File Length is not known!"); U- a+LS  
} hi30|^l-  
else if(nFileLength == -2)  :nHa-N3  
{ pGO)9?j_N  
System.err.println("File is not access!"); Dr!g$,9  
} ?
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else RN%*3{-  
{ ,'m<YTF  
for(int i=0;i<nStartPos.length;i++) *"pf3x6  
{ #H@rb  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  H?(I-vO  
} &7YTz3aj  
for(int i=0;i<nEndPos.length-1;i++) a\Ond#1p
 
{ M;{btu^a  
nEndPos = nStartPos[i+1]; c9eLNVM  
} kq SpZoV0'  
nEndPos[nEndPos.length-1] = nFileLength; Nn_n@K  
} 4{s3S2f=  
} D# "ppa}  
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//启动子线程 $dp;$X3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .ZB(!v/2  
for(int i=0;i<nStartPos.length;i++) 9f ^c9@=  
{ x dT1jI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >2[\WF*"X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1$*ZN4
 
nStartPos,nEndPos,i); {F/0pvP9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 12yr_   
fileSplitterFetch.start(); SGd[cA Ko  
} _^2rRz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hw@ `Q@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e7(iMe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OUd&fUmH  
nEndPos = " + nFileLength); QD6in>+B@  
// fileSplitterFetch[nPos.length-1].start(); (Mk9##R#  
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//等待子线程结束 W]]@pbG"H\  
//int count = 0; NEpom
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//是否结束while循环 ]}wo$7pO  
boolean breakWhile = false; _dgS@n;6  
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while(!bStop) ]>33sb S6  
{ =peodj^  
write_nPos(); fr\"MP  
Utility.sleep(500); H}R/_5g  
breakWhile = true; fq@r6\TI  
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for(int i=0;i<nStartPos.length;i++) ]Cfjs33H  
{ OM]d}}=Y  
if(!fileSplitterFetch.bDownOver) f(^? PGO  
{ 4pin\ZS:C  
breakWhile = false; 29xm66  
break; x.+r.cAXH  
} tJ{3Z}K  
} ']N1OVw^vf  
if(breakWhile) -A?6)ggf.  
break; xp!MA  
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:6 , `M,  
//count++; Z?Cl5o&lb  
//if(count>4) 1%v!8$  
// siteStop(); 8QYP\7}o  
}
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System.err.println("文件下载结束！"); M@k8;_5  
} l@ amAusE  
catch(Exception e){e.printStackTrace ();} CNo'qlvF5N  
} qT<OiIMj^  
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//获得文件长度 x6i7x"  
public long getFileSize() \gBsAZE  
{ B_gzpS]  
int nFileLength = -1; kqebU!0-  
try{ lUL6L4m  
URL url = new URL(siteInfoBean.getSSiteURL()); mW/6FC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hwz.5hV"  
httpConnection.setRequestProperty("User-Agent","NetFox"); eHQS\n  
t",=]k  

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int responseCode=httpConnection.getResponseCode(); f,jN"  
if(responseCode>=400) \jkMnS6FvL  
{ {Wi)
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processErrorCode(responseCode); }f l4^F  
return -2; //-2 represent access is error S%^*h{9u"  
} %kHe
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;?{N=x8  
String sHeader; *%3%Zj,{  
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for(int i=1;;i++) agbG)t0  
{ aUGRFK_6$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E*sQ|" g  
//Utility.log(in.readLine()); jc$gy`,F  
sHeader=httpConnection.getHeaderFieldKey(i); "^Ax}Jr  
if(sHeader!=null) ajy+%sXf=  
{ T3_3k.,|  
if(sHeader.equals("Content-Length")) sp-){k  
{ lpy(un  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); > [%ITqA$  
break; T{US
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}
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} fn~Jc~[G|  
else LX!MDZz  
break; "f Ni3<x]  
} S [$Os7  
} 3pk=c-x  
catch(IOException e){e.printStackTrace ();} `W*b?e|H1  
catch(Exception e){e.printStackTrace ();} NwISf  
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Utility.log(nFileLength); Fk-}2_=vi  
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return nFileLength; !4/s|b
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} f\|R<3 L  
\FL`b{!+ N  
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//保存下载信息（文件指针位置） 4Odf6v,*@  
private void write_nPos() RT~6#Caf  
{ MYlPG1X=?  
try{ ta*6xpz-\Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z'!sc"]W6  
output.writeInt(nStartPos.length); Ec/-f`8  
for(int i=0;i<nStartPos.length;i++) mu>L9Z~(L_  
{ i?+>,r@\p  
// output.writeLong(nPos); A*a:#'"*N  
output.writeLong(fileSplitterFetch.nStartPos); >!gW]{  
output.writeLong(fileSplitterFetch.nEndPos); wn&5Ul9Elb  
} UNC%<=  
output.close(); b~u53
  
} Qp5Y
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catch(IOException e){e.printStackTrace ();}  j1sgvh]D  
catch(Exception e){e.printStackTrace ();} [b?[LK}.  
} ?r%kif)  
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//读取保存的下载信息（文件指针位置） y.6Yl**l  
private void read_nPos() rHMr8,J;  
{ c+bOp 05o-  
try{ 6a%dq"5 +  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?j:g.a+U  
int nCount = input.readInt(); +vSp+X1E  
nStartPos = new long[nCount]; }u `~lw(Z  
nEndPos = new long[nCount]; ;+Mee^E>!  
for(int i=0;i<nStartPos.length;i++) % k}+t3aF  
{ X%lk] &2  
nStartPos = input.readLong(); HC$rC"f  
nEndPos = input.readLong(); o6@`aU  
} s~)I1G  
input.close(); <0M2qt8  
} I&s!}$cD  
catch(IOException e){e.printStackTrace ();} d>YX18'<Q  
catch(Exception e){e.printStackTrace ();} px~:'U  
} .}4^b\  
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private void processErrorCode(int nErrorCode) ;&~9k?v7L  
{ ,mY3oyu  
System.err.println("Error Code : " + nErrorCode); rF:l
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} <AN=@`+  
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: 6|nXL  
//停止文件下载 j
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public void siteStop() O,Sqh$6U  
{ }%lk$g';  
bStop = true; !hc#il'g].  
for(int i=0;i<nStartPos.length;i++) l(j._j~p  
fileSplitterFetch.splitterStop(); }^"#&w3<  
ysDGF@wZC  
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} 8_h:_7e  
} !gX(Vh*k  
//负责部分文件的抓取 DFvj  
**FileSplitterFetch.java D
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*/ FC&841F  
package NetFox; ig}H7U2q@  
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import java.io.*; <%ZlJ_cM  
import java.net.*; U_oei3QP  
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public class FileSplitterFetch extends Thread { ;>jLRx<KC  
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String sURL; //File URL I;rh(FMV  
long nStartPos; //File Snippet Start Position N&YQZ^o  
long nEndPos; //File Snippet End Position E!]d?t3b  
int nThreadID; //Thread's ID ;]I~
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boolean bDownOver = false; //Downing is over *m.4)2u=  
boolean bStop = false; //Stop identical =t!$72g\  
FileAccessI fileAccessI = null; //File Access interface +T*]!9%<`:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &l;wb.%ijW  
{ _2p D  
this.sURL = sURL; K!A;C#b!  
this.nStartPos = nStart; (+w.?l  
this.nEndPos = nEnd; {Ip)%uR  
nThreadID = id; g(-}M`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s&Lyg>>`  
} w7"&\8a  
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public void run() wU(N<9  
{ _]q%Hve  
while(nStartPos < nEndPos && !bStop) =CGB}qU l0  
{ em,j>qp  
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try{ "Wz74ble  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H;kk:s'  
httpConnection.setRequestProperty("User-Agent","NetFox"); {cMf_qQ  
String sProperty = "bytes="+nStartPos+"-"; r]yI5 ;  
httpConnection.setRequestProperty("RANGE",sProperty); YH-+s   
Utility.log(sProperty); FTT=h0t  
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InputStream input = httpConnection.getInputStream(); NoD\t(@h  
//logResponseHead(httpConnection); ;{S7bH'6m  
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byte[] b = new byte[1024]; NI)q<@ju
 
int nRead; a,~}G'U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n}!D)Gx  
{ 03^?+[C  
nStartPos += fileAccessI.write(b,0,nRead); e}bY9  
//if(nThreadID == 1) r>.^4Z@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kp>AZVk  
} 8iKupaaOX  
4M3{P  
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Utility.log("Thread " + nThreadID + " is over!"); OYwH$5  
bDownOver = true; ns;nle|m  
//nPos = fileAccessI.write (b,0,nRead); IP-}J$$1  
} jSMs<ox  
catch(Exception e){e.printStackTrace ();} [X=J]e^D  
} avwhGys#  
} ;y%C\YB#  
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//打印回应的头信息 ZW>?y$C+  
public void logResponseHead(HttpURLConnection con) }
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{ XJ9bY\>)q1  
for(int i=1;;i++) 3GUJlFj  
{ o^b4l'&o  
String header=con.getHeaderFieldKey(i); o:C],G_  
if(header!=null) DX)T}V&mP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z2soy-  
Utility.log(header+" : "+con.getHeaderField(header)); 7\p<k/TS  
else 2%oo.?!R  
break; m(c5g[6nO  
} e Zb8x  
} RBM(>lU:  
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public void splitterStop() ^7O,Vk"Z  
{ G: p!PB>=  
bStop = true; q9mYhT/Im  
} p/GYfa dU  
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xs ^$fn\  
} ecgGl,{  
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/* +""8aA  
**FileAccess.java JkMf+!  
*//文件访问(定位，写) Mk"V%)1k  
package NetFox; 2~BId&]  
import java.io.*; 3cztMi  
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#H1ng<QV  
public class FileAccessI implements Serializable{ %`Q<_LTU  
-A A='s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Axtf,x+lH  
RandomAccessFile oSavedFile; ,0=@cJ  
long nPos; m+Bt9|d  
beM}({:`  
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public FileAccessI() throws IOException U]h5Q.<SG  
{ ctg[C$<q|  
this("",0); pdQ6/vh  
} .sk$@Q  

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public FileAccessI(String sName,long nPos) throws IOException nS}XY  
{ HBc^[fJ^-  
oSavedFile = new RandomAccessFile(sName,"rw"); 8}0O @ wq  
this.nPos = nPos; jLEwFPz  
oSavedFile.seek(nPos); Zg@NMT  
} 8>sToNRNe  
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fy`e)?46  
public synchronized int write(byte[] b,int nStart,int nLen) ,.ln  
{ K8l|qe  
int n = -1; -H%806NAX7  
try{ 'b* yYX<  
oSavedFile.write(b,nStart,nLen); G^]7!:0  
n = nLen; fdD?"z  
} YAIDSZ&l[  
catch(IOException e) Bk~lE]Q3c7  
{ dfDz/sD*  
e.printStackTrace (); C NNyz$  
} }D7q)_g=  
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~7W?W<  
return n; ]Xur/C2A  
} - T,;Fr'  
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} McgTTM;E  
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/.<T^p@\&  
/* ()Z!u%j  
**SiteInfoBean.java );wSay>%(  
*/
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package NetFox; jB*%nB*x  
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public class SiteInfoBean { 2<Tbd"x?  
b8QA>]6A  
+s:!\(BM  
private String sSiteURL; //Site's URL }@Ij}Ab>  
private String sFilePath; //Saved File's Path a a=GW%  
private String sFileName; //Saved File's Name 0Ii* "?s  
private int nSplitter; //Count of Splited Downloading File dyRKmLb  
9pKN^FX,76  
=h?
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*  
public SiteInfoBean() y]B?{m``6  
{//nSplitter的缺省值为5 7u!i)<pn  
//default value of nSplitter is 5 i2SR.{&  
this("","","",5); ,F7W_f# @3  
} bb#F2r4  
hHsCr@i  
0*MY4r|-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V]cD^Fqp  
{ wuCiO;w  
sSiteURL= sURL; <FIc!  
sFilePath = sPath; ZR<T\w  
sFileName = sName; QCFLi n+r  
this.nSplitter = nSpiltter; IWvLt  
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} %|$h<~  
&13qlc6  
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public String getSSiteURL() n}MW# :eJe  
{ 6]yYiz2Xn  
return sSiteURL; rmS.$h@7 m  
} NGIbUH1[  
=*7K_M&  
zdFO&YHTw  
public void setSSiteURL(String value) =&RpW7]  
{ 'M>QA"*48E  
sSiteURL = value; cRPW  
} ~Rd,jfx  
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0|kkwZVPn  
public String getSFilePath() P,-f]k[_  
{ v#1}( hb  
return sFilePath; qRkY-0vBP  
} XKD0n^L[  
p|!5G&O,  
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public void setSFilePath(String value) `yYoVu*  
{ F?#^wm5TZ  
sFilePath = value; LT7C>b  
} HBHDu;u  
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IE7%u92  
public String getSFileName() <d89eV+  
{ qxKW%{6o  
return sFileName; Dv~W!T i  
} B:Y"X:Y  
{nvF>  
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public void setSFileName(String value) jeb]3i=pw  
{ >&pB&'A a  
sFileName = value; :;Z?2P5i  
} \4$V;C/n,  
I'6
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uG-t)pej  
public int getNSplitter() O5X@'.#rU  
{ UAleGR`,  
return nSplitter;  zciL'9  
} u={A4A#  
p;#@#>h  
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public void setNSplitter(int nCount) TS2zzYE6Z  
{ ckDWY<@v  
nSplitter = nCount; |E]`rfr  
} vs=8x\W  
} s=KK
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hIBW$  
^@91BY  
/* %?2:1o  
**Utility.java O+f'Ql  
*/ RaT.%:CRm  
package NetFox; Y8i'=Po%,  
#_(t46  
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public class Utility { mFk6a{+YX  
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:t)<$dtf[  
public Utility() Nbyc,a[o  
{ +HAd=DU  
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v% c-El%  
} \I-bZ|^  
]=ubl!0=:  
//线程睡眠 "|,;~k1  
public static void sleep(int nSecond) ~;AJB  
{ ;NoD4*  
try{ 7 'B9z/  
Thread.sleep(nSecond); V#Pz`D  
} @Jh;YDr`A  
catch(Exception e) +M s`C)f  
{ <&CzM"\Em  
e.printStackTrace (); ^2f2g>9j_C  
} -dO9y=?t  
} fU^6h`t  
M/x*d4b_  
//日志 E|9'{3$  
public static void log(String sMsg) p E56CM  
{ g[D`.  
System.err.println(sMsg); (X|`|Y  
} G5Z_[Q~z  
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8]2j*e0xV  
public static void log(int sMsg) Su>UXuNdE#  
{ cERmCe|/CG  
System.err.println(sMsg); )BX-Y@fpA  
} g@s'-8}X^  
} mA" 82"   
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!fT3mI6u\  
/* /OsTZ"*.2/  
**TestMethod.java xA#'%|"  
*/ tLc~]G*\`s  
package NetFox; U66}nN9  
D Kng.P  
!<AY0fpY  
public class TestMethod { ^hIKDc!.m  
67b[T~92o  
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public TestMethod() j87IxB?o  
{ ///xx/weblogic60b2_win.exe /sa\Ze;E  
try{ qE)G;Y<,1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .=% ,DT"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h"849c;C.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 99mo]1_  
fileFetch.start(); {S=gXIh(y  
} 2Hj;o  
catch(Exception e){e.printStackTrace ();} EC0M0qQ  
h6Q-+_5  
@ZFU< e$!  
} ckg8x&Z  
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public static void main(String[] args) 0Q= o"@  
{ QnPgp(d<  
new TestMethod(); %\n&iRwDF  
} \y*,N^wu  
} 4}t&AW4  
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