http断点续传简单实现（java)

/* C27:ty
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**SiteFileFetch.java }sXTZX  
*/ +x"uP  
package NetFox; FRd"F$U  
import java.io.*;
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import java.net.*; X.t4;  
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public class SiteFileFetch extends Thread { 3%Y:+%VE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean AYbO~_a\N  
long[] nStartPos; //开始位置 eQbHf  
long[] nEndPos; //结束位置 +Y%6y]8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y"q a
a  
long nFileLength; //文件长度 qNEp3WY:  
boolean bFirst = true; //是否第一次取文件 "bo0O7InOV  
boolean bStop = false; //停止标志 o:@Q1+p  
File tmpFile; //文件下载的临时信息 {6'Xz  
DataOutputStream output; //输出到文件的输出流 L|'^P3#7`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }g}Eh>U  
public SiteFileFetch(SiteInfoBean bean) throws IOException !a@)6or  
{ [C "\]LiX  
siteInfoBean = bean; 3$\k=q3`#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9"P|Csj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bx3Q$|M?  
if(tmpFile.exists ()) <gp?}Lk  
{ XNJ4T]><  
bFirst = false; [*',pG  
read_nPos(); s6bsV
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} bHwEd%f  
else I^?tF'E  
{
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nStartPos = new long[bean.getNSplitter()]; l[}4 X/  
nEndPos = new long[bean.getNSplitter()]; c2npma]DZ  
} z:,PwLU  
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} 4V,.Oi  
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public void run() S&-K!XyJ  
{ x;/LOa{LR  
//获得文件长度 ?E([Nc0T  
//分割文件 P\jGySj
  
//实例FileSplitterFetch @]@|H?  
//启动FileSplitterFetch线程 _wq?Pa<)e  
//等待子线程返回 " 9Gn/-V>  
try{ ||$&o!;/L  
if(bFirst) %**f`L%jN  
{ O`5,L[i1y  
nFileLength = getFileSize(); *T5;dh (  
if(nFileLength == -1) P$)g=/td1  
{ }s}g}t8v-  
System.err.println("File Length is not known!"); C?<pD+]b_  
} Q.mJ7T~T  
else if(nFileLength == -2) fO*jCl  
{ q-F K=r 5  
System.err.println("File is not access!"); 4qQ,1&!]S  
} d!,t_jM0  
else U.7fMc
#  
{ O `}EiyV  
for(int i=0;i<nStartPos.length;i++) :L[>!~YG_n  
{ aL
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); PVCoXOqh  
}
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for(int i=0;i<nEndPos.length-1;i++) JB_fS/I  
{ /).{h'^Hq\  
nEndPos = nStartPos[i+1]; R?{+&r.X  
} F/>_PH57  
nEndPos[nEndPos.length-1] = nFileLength; -pC8
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} h@:K=ggK  
} Zj`WRH4  
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//启动子线程 ]?Ef0?44  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &gXh:
.  
for(int i=0;i<nStartPos.length;i++) 8Lo#{`  
{ f[^f/jGm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K+B978XD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %Sr+D{B  
nStartPos,nEndPos,i); x$Dq0FX!%_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;a:H-iC  
fileSplitterFetch.start(); )BP*|URc  
} K@D\5s|1|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mDB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V>Wk\'h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \/a6h   
nEndPos = " + nFileLength); r* *zjv>  
// fileSplitterFetch[nPos.length-1].start(); M^FY6TT4O  
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//等待子线程结束 ($[wCHU`!  
//int count = 0; bF'rK'',  
//是否结束while循环 -fR:W{u  
boolean breakWhile = false; }lJ;|kx$  
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while(!bStop) tK#R`AQ  
{ K5""%O+  
write_nPos(); UX 1 )((  
Utility.sleep(500); JfY*#(
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breakWhile = true; ZCiCZ)oc  
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for(int i=0;i<nStartPos.length;i++) wX$:NOO  
{ /ZLY@&M  
if(!fileSplitterFetch.bDownOver) vvoxK0  
{ / HTY>b  
breakWhile = false; qe~x?FO_>  
break; bDI%}k9#  
} "q@m6fs  
} c OYDN[k  
if(breakWhile) okNo-\Dh!  
break; G0cG%sIl  
;JW_4;-  
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//count++; NFK
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//if(count>4) y8Va>ul"U  
// siteStop(); 7R+(3NU1A  
} 6b|?@  
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System.err.println("文件下载结束！"); sV^:
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} ']]
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catch(Exception e){e.printStackTrace ();} $o^Z$VmL  
} k9|5TLXq?  
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//获得文件长度 6_LeP9s )  
public long getFileSize() 2
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{ DSGcxM+  
int nFileLength = -1; )G? qX.D  
try{ ^)VwxH:s  
URL url = new URL(siteInfoBean.getSSiteURL()); :|7#D,2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '`];=QY9pg  
httpConnection.setRequestProperty("User-Agent","NetFox"); |@q
w  
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int responseCode=httpConnection.getResponseCode(); v*;d  
if(responseCode>=400) 8
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{ xNP_>Qa~  
processErrorCode(responseCode); 7ubz7*  
return -2; //-2 represent access is error p7?  
} vDy&sgS$<  
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String sHeader; 5{Cz!ut;tE  
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for(int i=1;;i++) }Q7y tE  
{ 4#U}bN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3Ob.OwA  
//Utility.log(in.readLine()); R[WiW RfD  
sHeader=httpConnection.getHeaderFieldKey(i); |"H 2'L$  
if(sHeader!=null) ~z,o):q1}  
{ 2[E wN!IZ  
if(sHeader.equals("Content-Length")) <v"o+  
{ !e$gp(4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5J5si<v25  
break; / )0hsQs  
} w =^.ICyb@  
} UZZJtQt  
else <hT\xBb:  
break; ^;C&  
} g7oY
1;  
} %H{p&ms  
catch(IOException e){e.printStackTrace ();} '<Z[e`/  
catch(Exception e){e.printStackTrace ();} ^0VL](bD>  
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Utility.log(nFileLength); q76POytV|  
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return nFileLength;  ;C]Ufk  
} h}b:-a  
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//保存下载信息（文件指针位置） v=`yfCX-qX  
private void write_nPos() V\~.  
{ 9&Y@g)+2  
try{ *zfgO pK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :yay:3qv  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) Bx\&7|,x  
{ V0ze7tSG[f  
// output.writeLong(nPos); f^c+M~\JKj  
output.writeLong(fileSplitterFetch.nStartPos); qsj{0Go  
output.writeLong(fileSplitterFetch.nEndPos); p [O6  
} !iXRt")  
output.close(); \1EuHQ?  
} b*|~F  
catch(IOException e){e.printStackTrace ();} =Q#I@SVp2$  
catch(Exception e){e.printStackTrace ();} ^:nc'C gP  
} Ts iJK  
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//读取保存的下载信息（文件指针位置） yzK;  
private void read_nPos() 
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{ t0)1;aBZ  
try{ 8`=?_zF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {@Wv@H+4  
int nCount = input.readInt(); %idBR7?`g  
nStartPos = new long[nCount]; 7Q 3!=b  
nEndPos = new long[nCount]; 5=>1>HYM  
for(int i=0;i<nStartPos.length;i++) 9>}&dQ8  
{ '3.\+^3  
nStartPos = input.readLong(); $:ush"=f8^  
nEndPos = input.readLong(); nD  wh  
} "CJVt
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input.close(); j50vPV8m  
} MJn-] E  
catch(IOException e){e.printStackTrace ();} _k84#E0  
catch(Exception e){e.printStackTrace ();} O&%'j  
} |OQ]F  
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private void processErrorCode(int nErrorCode) fv+]iK<{  
{ >7U/TVd&  
System.err.println("Error Code : " + nErrorCode); 1HJ: ?]  
} .35(MFvq!  
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//停止文件下载 (f/(q-7VWt  
public void siteStop() -YoL.`s1  
{ 1ni+)p>]  
bStop = true; 6jE.X  
for(int i=0;i<nStartPos.length;i++) &OR(]Wt0  
fileSplitterFetch.splitterStop(); N['DqS =  
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} 0cG'37[  
} bWPsfUn#  
//负责部分文件的抓取 z4u&#.bU  
**FileSplitterFetch.java ]HKt7 %,  
*/ jP@ @<dt  
package NetFox; {QG.> lB  
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import java.io.*; Q3@zUjq_Q  
import java.net.*;  A l[ZU  
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public class FileSplitterFetch extends Thread { Ds1h18  
*Pm
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String sURL; //File URL I{Du/"r#  
long nStartPos; //File Snippet Start Position 84ij4ZYe  
long nEndPos; //File Snippet End Position $b8[/],  
int nThreadID; //Thread's ID -cqE^qAdX  
boolean bDownOver = false; //Downing is over z?/_b  
boolean bStop = false; //Stop identical K3&xe(  
FileAccessI fileAccessI = null; //File Access interface x}G:n[B7_V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h nydH-;cz  
{ *ug~LK5Y.  
this.sURL = sURL; v^"\e&XL  
this.nStartPos = nStart; E@VQxB7+  
this.nEndPos = nEnd; /t5)&  
nThreadID = id; J[/WBVFDf  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 OB>Hiy   
} z} fpV T  
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41 F;X{Br  
public void run() N8A)lYT]_u  
{ )JMqC+J3*t  
while(nStartPos < nEndPos && !bStop) c*KE3:  
{ ~IhAO}1  
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try{ <q63?M
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URL url = new URL(sURL); \gA!)q.;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~^wSwd[  
httpConnection.setRequestProperty("User-Agent","NetFox"); NuZ2,<~9  
String sProperty = "bytes="+nStartPos+"-"; Dfs^W{YA  
httpConnection.setRequestProperty("RANGE",sProperty); =VC18yA  
Utility.log(sProperty); I}f`iBG  

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InputStream input = httpConnection.getInputStream(); 96WzgHPWo  
//logResponseHead(httpConnection); X[tt'5  
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byte[] b = new byte[1024]; pcMzLMG<  
int nRead; !GO
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0X)vr~`  
{ j>8DaEfwx  
nStartPos += fileAccessI.write(b,0,nRead); ;|Cdq  
//if(nThreadID == 1) s5~k]"{j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rPH7 ]]  
} i>
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Utility.log("Thread " + nThreadID + " is over!"); "i&)+dr-  
bDownOver = true; B{Q}^Mcxy  
//nPos = fileAccessI.write (b,0,nRead); <rC%$tr  
} U[C>Aoze  
catch(Exception e){e.printStackTrace ();} 5|*{~O|  
} (MGgr  
} MQ,K%_m8  
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$6Ma{rC|  
//打印回应的头信息 qbyYNlXqm  
public void logResponseHead(HttpURLConnection con) \'|n.1Fr  
{ Jr!^9i2j'  
for(int i=1;;i++) t:wBh'K~R8  
{ h'y"`k-  
String header=con.getHeaderFieldKey(i); yr
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if(header!=null) K0w}l" )A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [>ghs_?dZ  
Utility.log(header+" : "+con.getHeaderField(header)); CPB{eQeDuv  
else u\LNJo| B  
break; 1$Hou   
} Q4XlYgIV2A  
} oh5'Isb$  
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public void splitterStop() Q/o,2R  
{ |>Q>d8|k  
bStop = true; ]zx%"SUM  
} 2u.0AG   
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} bPVk5G*ruP  
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/* ("U<@~  
**FileAccess.java JrcbJ
t  
*//文件访问(定位，写) b1Vr>:sK47  
package NetFox; 4,y7a=qf3  
import java.io.*; f*%kHfaXgN  
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public class FileAccessI implements Serializable{ WK|5:V8E  
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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 Ii
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RandomAccessFile oSavedFile; T)P)B6q  
long nPos; Gz&}OO  
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public FileAccessI() throws IOException *}2L4]  
{ X]y:uD{  
this("",0); b8d0]YS  
} q,Gymh;  
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public FileAccessI(String sName,long nPos) throws IOException ^J]&($-  
{ `W86]ut[  
oSavedFile = new RandomAccessFile(sName,"rw"); : UeK0  
this.nPos = nPos; }=X: F1S  
oSavedFile.seek(nPos); o
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} ZLjAhd)  
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3\W/VBJJ  
public synchronized int write(byte[] b,int nStart,int nLen) hs7!S+[.$$  
{ N sdpE?V  
int n = -1; g8O6 b  
try{ 44KoOY_  
oSavedFile.write(b,nStart,nLen); U:8[%a  
n = nLen; t7byOMC  
} "$(+M t^  
catch(IOException e) mx^Ga=: ?  
{ \3hA_{ w  
e.printStackTrace (); T'pL&@,Q  
} {+9RJmZg  
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return n; :)1"yo\  
} P<g(i 6]  
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} ]5'$EAsuW  
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/* "
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**SiteInfoBean.java @1CXc"IgA  
*/ C*mVM!D);!  
package NetFox; *}\M!u{J  
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public class SiteInfoBean { `XxnQng  
&_L%wV|[  
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private String sSiteURL; //Site's URL t"$~o:U&)  
private String sFilePath; //Saved File's Path b`X''6  
private String sFileName; //Saved File's Name m(8Tup|  
private int nSplitter; //Count of Splited Downloading File ]FCP|Jz  
>._d2.Q'  
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public SiteInfoBean() 6qT@M0)i  
{//nSplitter的缺省值为5 SES.&e|!6  
//default value of nSplitter is 5 ?4':~;~  
this("","","",5); CyIlv0fd}  
} m?kiGC&m  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x*Z'i<;B  
{ `n$Ak5f  
sSiteURL= sURL; Z1 Nep!  
sFilePath = sPath; u ON(LavB  
sFileName = sName; r,;ca6>5H  
this.nSplitter = nSpiltter; DMUirA;  
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8n3]AOc'~-  
} poBeEpbs  
6nTM~]5.  
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public String getSSiteURL() ~kZdep^]  
{ F CYGXtc  
return sSiteURL; M5n
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} =e6pv
#  
-$8
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public void setSSiteURL(String value) Ic(qA{SM  
{ `O6#-<>  
sSiteURL = value; F;Q,cg M  
} s!(R  
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public String getSFilePath() HTh?&u\QG  
{
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return sFilePath; ZxvH1q
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} es7;eH*O9  
8$NVVw]2,  
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public void setSFilePath(String value) =2&\<Q_Fi  
{ b~zSsws.  
sFilePath = value; _=$~l^Y[  
} ,1ev2T  
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public String getSFileName() MT/jpx  
{ {]>c3=~FQb  
return sFileName; [S'1OR$FQ\  
} Q:q0C  +T  
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public void setSFileName(String value) hi,=" /9
 
{ &>qUT]w  
sFileName = value; 7$<pdayd  
} &m3-][!n  
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public int getNSplitter() GDLi?3q  
{ ^(JrOh'  
return nSplitter; `%Fp'`ZM$8  
} OG}890$n  
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public void setNSplitter(int nCount) O}"oz3H  
{ yx8G9SO?  
nSplitter = nCount; PMP{|yEx"  
} 1"y!wsM%  
} "=a3"/u  
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/* e=9/3?El  
**Utility.java i\CA6I  
*/ oB 1Qw'J w  
package NetFox; w>2lG3H<  
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public class Utility { ,g?ny<#o  
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public Utility() =>'8<"M5z  
{ yu6~:$%H  
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} *fm?"0M5  
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//线程睡眠 *z[vp2 TN  
public static void sleep(int nSecond) 9i\}^s2  
{ eP2Q2C8g  
try{ dSwfea_  
Thread.sleep(nSecond); tz]0F5  
} o'lG9ePM|  
catch(Exception e) Z0&^(Fb  
{ FJ84'T\~  
e.printStackTrace (); bbjba36RO  
} JM;bNW8  
}
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}4>u_)nt  
//日志 ^x&x|ckR!  
public static void log(String sMsg) 4PVg?  
{ 21OfTV-+3  
System.err.println(sMsg); n@`3O'S  
} '`upSJ;e  
<l1/lm<#  
`:lcN0n  
public static void log(int sMsg) TzC(YWt  
{ ,P<I<QYu  
System.err.println(sMsg);  _ %mm  
} gp9O%g3'  
} -}m  
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/* lSR\wz*Fk  
**TestMethod.java L~ax`i1:"  
*/ XF: wsC  
package NetFox; EG\L]fmD  
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public class TestMethod { O5du3[2x7a  
m LajiZ Bf  
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public TestMethod() ScJ:F-@>  
{ ///xx/weblogic60b2_win.exe xd3mAf  
try{ cPIyD?c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q+f|.0r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !}c D e12  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _dd_Z40R  
fileFetch.start(); KdR\a&[MA  
} O#igH  
catch(Exception e){e.printStackTrace ();} 26~rEOgJ  
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} d '2JMdbc  
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public static void main(String[] args) 'tTlBf7#  
{ Db2#QQ  
new TestMethod(); ?Ho$fGz  
} fXevr `  
} h`fZ8|yw  
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