http断点续传简单实现（java)

/* i52:<< 8a  
**SiteFileFetch.java {2%@I~US  
*/ NU|T`gP  
package NetFox; `=~d^wKYJ3  
import java.io.*; 'q=Ly?9  
import java.net.*; oNr~8CA`  
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public class SiteFileFetch extends Thread { LP:C9Ol\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g4*]R>f  
long[] nStartPos; //开始位置 t6O/Q0_  
long[] nEndPos; //结束位置 c>RS~/Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'y.'Xj:l  
long nFileLength; //文件长度 c~+l|r=u?  
boolean bFirst = true; //是否第一次取文件 A?*_14&  
boolean bStop = false; //停止标志 w%[`'_[  
File tmpFile; //文件下载的临时信息 agFWye  
DataOutputStream output; //输出到文件的输出流 3g]Sp/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $z~sN  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q
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{ 8L<G
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siteInfoBean = bean; Y&k6Xhuao  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y|=/*?o}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m4~Co*]w  
if(tmpFile.exists ()) 1e>,QX
  
{ 6*/o  
bFirst = false; "1H?1"w~  
read_nPos(); %<q l  
} Y.qlY3iBp  
else 7)NQK9~  
{ ttPa[h{!  
nStartPos = new long[bean.getNSplitter()]; q*oUd/F8  
nEndPos = new long[bean.getNSplitter()]; zUqt^_  
} I"^ `!8<q  
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} a(Bo.T<2@  
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public void run() YB h:  
{ :cmfy6h]  
//获得文件长度 `7P4O   
//分割文件 z6vRTY  
//实例FileSplitterFetch K4i#:7r'b  
//启动FileSplitterFetch线程 (
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//等待子线程返回 EnJAHgRV;e  
try{ |*0oz=  
if(bFirst) Y B@\"|}  
{ Yz0ruhEMk  
nFileLength = getFileSize(); #~54t0|Cd>  
if(nFileLength == -1) UB
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{ 9~DoF]TM  
System.err.println("File Length is not known!"); <D4.kM  
} <`sVu  
else if(nFileLength == -2) :2?J#/o  
{ 6>)]7
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System.err.println("File is not access!"); b+\jFGC%6=  
} >De\2gbJ  
else KL!k'4JNY  
{ 6I(y`pJ  
for(int i=0;i<nStartPos.length;i++) KP7bU9odJ  
{ gEtDqq~y@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *TA${$K  
} 8w~I(2S:#  
for(int i=0;i<nEndPos.length-1;i++) Z mF}pa,gd  
{ LbtcZ)D!  
nEndPos = nStartPos[i+1]; B3
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} u4NMJnX  
nEndPos[nEndPos.length-1] = nFileLength; WEUr;
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} VcT(n7  
}  "
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vV-ATIf
^  
,)XT;iGQe  
//启动子线程 `h(JD$w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;Yyg(Ex  
for(int i=0;i<nStartPos.length;i++) [[QrGJr  
{ 1agyT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3Ec5:Caz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F'W{\4  
nStartPos,nEndPos,i); 3'O+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _(3VzI'G  
fileSplitterFetch.start(); 'O8"M  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MZZ4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f GE+DjeA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :S0r)CNP  
nEndPos = " + nFileLength); z)=D&\HX  
// fileSplitterFetch[nPos.length-1].start(); @$gvV]
dA  
|[}YM%e  
?3kfhR  
//等待子线程结束 41mg:xW(J  
//int count = 0; AQU4~g mI  
//是否结束while循环 li8l+5d q  
boolean breakWhile = false; c~b[_J)  
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,(}7 ST  
while(!bStop) abuHu'73  
{ p@/!+$^{  
write_nPos(); _\>?.gg$  
Utility.sleep(500); EE#4,d`J  
breakWhile = true; C;}~C:aJ  
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for(int i=0;i<nStartPos.length;i++) s\1h=V)!H  
{ u1/4WYJeJ  
if(!fileSplitterFetch.bDownOver) PQ<""_S||  
{ E< "aUnI  
breakWhile = false; =Bi>$Ly  
break; }H!c9Y  
} a[]=*(AZI  
} _-x|g~pV*  
if(breakWhile) 2B3H-`  
break; .slA}  

,>V|%tD'  
]C3{ _?=  
//count++; &Vg+n0  
//if(count>4) '}e_8FS  
// siteStop(); h^D?G2O  
} C$SuFL(pb  
U8-#W(tRR  
H ifKa/}P8  
System.err.println("文件下载结束！"); GL_YT.(!  
} 6!bVPIyYO  
catch(Exception e){e.printStackTrace ();} "6 |j 0?Q  
} )."_i64  
%/"I.\%d  
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//获得文件长度 z6]dF"N  
public long getFileSize() 9u^PM  
{ u\ro9l  
int nFileLength = -1; L3GA]TIf  
try{ m~'!  
URL url = new URL(siteInfoBean.getSSiteURL()); @)1>ba  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ztTj2M"  
httpConnection.setRequestProperty("User-Agent","NetFox"); -KhNsUQk  
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int responseCode=httpConnection.getResponseCode(); W@`2+}  
if(responseCode>=400) n^B9Mh@  
{ <K;  
processErrorCode(responseCode); 5.5<.")  
return -2; //-2 represent access is error pYf57u  
} EudX^L5U<d  
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^\ A[^' 9  
String sHeader; Z^E>)!t  
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for(int i=1;;i++) G2qv)7{l2  
{ h?R{5?RxK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *;t\!XDgp  
//Utility.log(in.readLine()); ~k\Dde  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) s|F}Ab
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{ vZ,DJ//U,  
if(sHeader.equals("Content-Length")) |_."U9!Z^  
{ 2(LF @xb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /By:S/[1pL  
break; W
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} WX .Ax$fT  
} Em)U`"j/9  
else @<kY,ox@~  
break; cq]JD6937  
} 5.
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} ,]`|2j  
catch(IOException e){e.printStackTrace ();} ~_Q~AOFM  
catch(Exception e){e.printStackTrace ();} $mxm?7ZVR  
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Utility.log(nFileLength); f~Y;ZvB  
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return nFileLength; OT0%p)  
} )5T82=[h<  
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}uZ/^_U.  
//保存下载信息（文件指针位置）
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private void write_nPos() 4>^LEp  
{ `%QXaKO-  
try{ (#kKL??W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Hjhgu=  
output.writeInt(nStartPos.length); &~mJ ).*  
for(int i=0;i<nStartPos.length;i++) '8J!(+  
{ YRg"{[+#]k  
// output.writeLong(nPos); <OY (y#x  
output.writeLong(fileSplitterFetch.nStartPos); [|".j#ZlK  
output.writeLong(fileSplitterFetch.nEndPos); srPczVG*  
} L0l'4RRm\  
output.close(); ]K?;XA3dZ  
} {wy{L-X  
catch(IOException e){e.printStackTrace ();} U#V&=~-  
catch(Exception e){e.printStackTrace ();} cWtuI(.  
} /!Ay12lKE}  
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m)
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//读取保存的下载信息（文件指针位置） /< k&[  
private void read_nPos() [)+wke9  
{ BG|
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try{ r[?GO"ej5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (E;+E\E  
int nCount = input.readInt(); = N&5]Z  
nStartPos = new long[nCount]; SzP`(}AU  
nEndPos = new long[nCount]; NSawD.9mV  
for(int i=0;i<nStartPos.length;i++) pf
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{ oyB gF\  
nStartPos = input.readLong(); [Dhqyjq  
nEndPos = input.readLong(); CvHE7H|-{  
} fmq''1u  
input.close(); K| dI'TnW  
} 44NMof8N  
catch(IOException e){e.printStackTrace ();} Gv[s86AP,  
catch(Exception e){e.printStackTrace ();} 1=Z!ZY}}e  
} 3Ccy %;  
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private void processErrorCode(int nErrorCode) }u9#S  
{ ?g\emhG  
System.err.println("Error Code : " + nErrorCode); =oBlUE  
} 0~~yYo&  
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//停止文件下载 gw!d[{#  
public void siteStop() Zg$S% 1(Q  
{ bwM?DY
 
bStop = true; FnKC|X  
for(int i=0;i<nStartPos.length;i++) 3eg6 CdT  
fileSplitterFetch.splitterStop(); @9eN\b%I^H  
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} 2X<%BFsE  
} WkiPrQ0]:  
//负责部分文件的抓取 iC3C~?,
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**FileSplitterFetch.java a:8 MoH4  
*/ Kt](|  
package NetFox; )s,LFIy<A  
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import java.io.*; y XKddD  
import java.net.*; &?1O D5  
{,i-V57-h  
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public class FileSplitterFetch extends Thread { (H5#r2h%Y
 
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String sURL; //File URL !zvjgDlZv  
long nStartPos; //File Snippet Start Position ?2l`%l5(  
long nEndPos; //File Snippet End Position  =n5n  
int nThreadID; //Thread's ID 9/!1J  
boolean bDownOver = false; //Downing is over AT)b/y
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boolean bStop = false; //Stop identical $|xSM2  
FileAccessI fileAccessI = null; //File Access interface Ml$<x"Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :_y!p  
{ 5[g\.yi2_]  
this.sURL = sURL; UOsK(mB  
this.nStartPos = nStart; iMt3h8  
this.nEndPos = nEnd; ,cL;,YN  
nThreadID = id; $'I&u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3rB0H   
} ^~I@]5Pq  
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public void run() f+Acs*.GQ  
{ P woiX#vz  
while(nStartPos < nEndPos && !bStop) :^PksR  
{ j{YYG|  
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try{ ;<N:!$p  
URL url = new URL(sURL); }mXYS|{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C6[W/,eS  
httpConnection.setRequestProperty("User-Agent","NetFox"); @`dg:P*[  
String sProperty = "bytes="+nStartPos+"-"; BaW4 s4u  
httpConnection.setRequestProperty("RANGE",sProperty); 6IG?t  
Utility.log(sProperty); A $gn{ c  
/
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InputStream input = httpConnection.getInputStream(); t|eH'"N%o  
//logResponseHead(httpConnection); o^vX\a?`u  
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byte[] b = new byte[1024]; ;o3gR4u_L  
int nRead; N"G aQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P2a5<#_|  
{ uD>=  
nStartPos += fileAccessI.write(b,0,nRead); 3y6\0|{1  
//if(nThreadID == 1) R ,qQC<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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} u*G<?  
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Utility.log("Thread " + nThreadID + " is over!"); NC%hsg^0/  
bDownOver = true; ^sD M>OHp  
//nPos = fileAccessI.write (b,0,nRead); Mg.%&vH\  
} W~'xJ  
catch(Exception e){e.printStackTrace ();} L"|Bm{Run  
} [|OII!"  
} *z?Uh$I4  
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//打印回应的头信息 j4?Qd0z  
public void logResponseHead(HttpURLConnection con) 4u6 FvN  
{ ::oFL#+  
for(int i=1;;i++) s2{SbOBis  
{ +gX
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String header=con.getHeaderFieldKey(i); !k)6r6  
if(header!=null) |nZ^RCHog  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); RW L0@\  
Utility.log(header+" : "+con.getHeaderField(header)); _-TplGSO=c  
else jr4xh{Z`  
break; iPTQqx-m$7  
} dtC@cK/,D  
} ;o!p9MEpz;  
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public void splitterStop() Y[6T7eZ0g  
{ D*%am|QL  
bStop = true; b# N"}-\^  
} ?{S>%P A_B  
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} ST*h{:u&A  
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/* lGd'_~'=  
**FileAccess.java r(>S
  
*//文件访问(定位，写) *): |WDR  
package NetFox; 5naFnm7%  
import java.io.*; %":3xj'EEI  
<b:%o^  
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public class FileAccessI implements Serializable{ OIrm9D#  
}`"}eN @,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +~^S'6yB  
RandomAccessFile oSavedFile; TEC^|U`G  
long nPos; SyvoN,;Q  
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public FileAccessI() throws IOException (9]Uuvfp6"  
{ 4[gmA  
this("",0); u&:N`f  
} [3m\~JtS  
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public FileAccessI(String sName,long nPos) throws IOException ,{_i{WV  
{ 4\;zz85E  
oSavedFile = new RandomAccessFile(sName,"rw"); W0gS>L_  
this.nPos = nPos; I=0c\ U}  
oSavedFile.seek(nPos); \OwF!~&  
} 9M96$i`P  
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&6x(
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public synchronized int write(byte[] b,int nStart,int nLen) '}Fe&%  
{ yfG;OnkZ  
int n = -1; 46:<[0Psl/  
try{ uH[WlZ4  
oSavedFile.write(b,nStart,nLen); aCG rS{  
n = nLen; >yO/p(/;jR  
} vzIo2,/7  
catch(IOException e) S<nF>JRJa  
{ tu -a`h_NJ  
e.printStackTrace (); Q0xO;20  
} ]Ur/DRNS  
[b++bCH3  
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return n; S#/BWNz|  
} 8}'iEj^e  
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} sVFO&|
L  
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/* ^j<v~GTx+  
**SiteInfoBean.java ,->ihxf  
*/ ?qjdmB|w  
package NetFox; OgF[=  
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public class SiteInfoBean { [DaAvN^0A  
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private String sSiteURL; //Site's URL gT)(RS`_)  
private String sFilePath; //Saved File's Path uN%C
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private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File Ik:G5m<ta  
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' @!&{N  
public SiteInfoBean() tiK M+ ;C  
{//nSplitter的缺省值为5 bQaRl=:[:  
//default value of nSplitter is 5 6N@=*0kh-  
this("","","",5); *l_a=[<[  
} '}hSh  
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C @Ts\);^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3qWrSziD  
{ }i+C)VUX   
sSiteURL= sURL; {Ydhplg{  
sFilePath = sPath; lS=YnMs6a  
sFileName = sName; <-`bWz=+  
this.nSplitter = nSpiltter; ufL,Kq4  
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} wkt4vE87  
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public String getSSiteURL() t#(NfzN  
{ stw@@GQ  
return sSiteURL; 0}i 9`p  
} lU1SN/'zx  
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public void setSSiteURL(String value) X_PzK'#m  
{ DwBe_h.  
sSiteURL = value; OS[ s Qo5  
} ?qQ{]_q1&.  
3U6QYD55]]  
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public String getSFilePath() tY_=[6?Zu  
{ S]H[&o1o  
return sFilePath; I"]E}nd)  
} YdI6|o@vc  
HS=w9:,  
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public void setSFilePath(String value) R&uPoY,f  
{ ,88B@a  
sFilePath = value; +C=vuR  
} I]ej ]46K  
P}6#s'07~  
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public String getSFileName() AG >D,6Y  
{ tN{0C/B9  
return sFileName; (CQ! &Z8  
} 8i6iynR  
i?_Q@uA~<:  
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public void setSFileName(String value) T#&1q]P1F  
{ frbd{o  
sFileName = value; S(=@2A+;  
} c:${qY:!  
rT="ciQ  
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public int getNSplitter() B~o3Z  
{ ^ iu)vED  
return nSplitter; 8z93ETv7`  
} -dMH>e0  
2`i&6iz  
[CHN3&l-5S  
public void setNSplitter(int nCount) #mH28UT  
{ ?3DL .U{  
nSplitter = nCount; :/->m6C`0  
} iu{y.}?  
} @G&oUhS  
`y'%dY}$n  
 3B#fnj  
/* 9Zx| L/\  
**Utility.java A7QT4h&6  
*/ F]OWqUV  
package NetFox; T#E{d  
?~ybFrc  
mcwd
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public class Utility { qRT5|\l  
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public Utility() K*~xy bA  
{ kU:Q&[/jzH  
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} Q8TR@0d  
.t^1
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//线程睡眠 319 4]  
public static void sleep(int nSecond) QP%AJ[3ea%  
{ .9DhD=8aIO  
try{ ,-])[u  
Thread.sleep(nSecond); OfLj 4H6Q  
} i?>
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catch(Exception e) &*Z)[Bl  
{  uvDOTRf  
e.printStackTrace (); ILG&l<!E  
} BDp(&=ktq  
} "dG*HKrr  
6\h*SBI?(  
//日志 :CM2kh"Iu  
public static void log(String sMsg) _576Qa'rm  
{ h6Vd<sV\tf  
System.err.println(sMsg); TGpdl`k\T  
} =)#XZ[#F  
B"7~[,he  
a#0*#&?7@  
public static void log(int sMsg) |}l/6WHB  
{ `[=/f=Q}  
System.err.println(sMsg); ='#7yVVcs  
} \hJLa  
} M7DoAS{6e  
BT:b&"AR[  
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/* lfoPFJ Z  
**TestMethod.java m=`V  
*/ \KEmfCx'n  
package NetFox; jJ>I*'w  
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public class TestMethod { %z1hXh#+  
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LNgFk%EH  
public TestMethod() qE^u{S4Z@  
{ ///xx/weblogic60b2_win.exe ]VVx2ERs  
try{ iA2TvP#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m,J9:S<5;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FOa2VP%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]{-ib:f
~  
fileFetch.start(); J<L"D/  
} uN&49o  
catch(Exception e){e.printStackTrace ();} `)jAdad-s  
$nthMx$  
_hB7;N3  
} r^d:Po  
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public static void main(String[] args) btf]~YN  
{ 9@(V!G  
new TestMethod(); #1>c)_H  
} ?cr^.LV|h^  
} 7*&q"   
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