http断点续传简单实现（java)

/* p"Ki$.Y  
**SiteFileFetch.java `$|!h-"  
*/ 8NLTq|sW  
package NetFox; Snx_NH#tA  
import java.io.*; 31b9pi}nf  
import java.net.*; eup#.#J  
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public class SiteFileFetch extends Thread { $N[-ks2{@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X5kIM\  
long[] nStartPos; //开始位置 B6tp,Np5,  
long[] nEndPos; //结束位置 mO$]f4}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [G{{f  
long nFileLength; //文件长度 "i$Avm  
boolean bFirst = true; //是否第一次取文件 oy90|.]G  
boolean bStop = false; //停止标志 Cs$wgm*  
File tmpFile; //文件下载的临时信息 A-:58Qau+  
DataOutputStream output; //输出到文件的输出流 )]Xj"V2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (7w`BR9B  
public SiteFileFetch(SiteInfoBean bean) throws IOException &-#!]T-P:E  
{ `A O_e4D0i  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;'!G?)PZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IDbqhZp(  
if(tmpFile.exists ()) tiJY$YqA  
{ ]Bw2>6W  
bFirst = false; {f]K3V  
read_nPos(); nunTTE,iq%  
} |<&9_Aq_  
else \4y7!  
{ qX[a\HQa  
nStartPos = new long[bean.getNSplitter()]; -AcLh0pc  
nEndPos = new long[bean.getNSplitter()]; *"#62U6  
} gV]]?X&  
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} D{YAEG   
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public void run() >$h*1/  
{ *Q=ER  
//获得文件长度 p$dVGvM(  
//分割文件 \"BoTi'2!  
//实例FileSplitterFetch v[VUX69  
//启动FileSplitterFetch线程 s"b()JP  
//等待子线程返回 `HXP*Bp#  
try{ T-x1jC!B'  
if(bFirst) *het_;)+{  
{ $PA=7`\MP/  
nFileLength = getFileSize(); kyl
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if(nFileLength == -1) ,@
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{ qUX  
System.err.println("File Length is not known!"); e<s56<3j  
} 'j>+eA>  
else if(nFileLength == -2) ?eD,\G  
{ 'vKB]/e;  
System.err.println("File is not access!"); 0MDdcjqw  
} rJi;"xF8  
else (.TkvUj`  
{ b(wzn`Z%Et  
for(int i=0;i<nStartPos.length;i++) ^znj
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{ #;GIv
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); EIO!f[]o  
} EacqQFErl  
for(int i=0;i<nEndPos.length-1;i++) g _fvbVX  
{ g7!P|  
nEndPos = nStartPos[i+1]; WbZ{) i  
} 9An_zrJ%i  
nEndPos[nEndPos.length-1] = nFileLength; t/z]KdK P  
} ;n?72&h  
} ~I<yN`5(a  
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//启动子线程 -FA]%Pl<'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D)z'FOaI  
for(int i=0;i<nStartPos.length;i++) Iw(2D(se  
{ [OJ@{{U%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oL0Q%_9hW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w$Lpuun{  
nStartPos,nEndPos,i); z#*M}RR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F,{M!dL  
fileSplitterFetch.start(); _urv We  
} h_6QVab@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AkdONKO8{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -DDH)VO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A
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nEndPos = " + nFileLength); P1DYjm[+D  
// fileSplitterFetch[nPos.length-1].start(); z:f[<`,GT  
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//等待子线程结束 0] e=  
//int count = 0; e|Iylv[3  
//是否结束while循环 yv||:wZC  
boolean breakWhile = false; VyK]:n<5Q  
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while(!bStop) |,CWk|G  
{ *44^M{ti<  
write_nPos(); z VleJ!d  
Utility.sleep(500); _ +Ww1f  
breakWhile = true; }{;m:Iia_  
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for(int i=0;i<nStartPos.length;i++) O-- "\4  
{ O57n<J'6  
if(!fileSplitterFetch.bDownOver) l1}=>V1  
{ GKdQ  
breakWhile = false; LY}%|w  
break; 8 PI>Q  
} nTO,d$!Kp  
} G]5m@;~l5  
if(breakWhile)
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break; $I&DAGV0  
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u '-4hU  
//count++; u'cM}y&  
//if(count>4) ^n#6CW*n  
// siteStop(); ]S+NH[g+  
} I3uS?c  
|&Gm.[IX;q  
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System.err.println("文件下载结束！"); oiYI$ql3L  
} GkqKIs  
catch(Exception e){e.printStackTrace ();} F VBuCi?W  
} ` MIZqHM @  
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AcV 2l  
//获得文件长度 8Wx>,$k  
public long getFileSize() dcUaZfON  
{ CDcZ6.f  
int nFileLength = -1; ?)<DEu:Y  
try{ Lqy]bnY  
URL url = new URL(siteInfoBean.getSSiteURL()); gj{2"tE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7+wy`xi  
httpConnection.setRequestProperty("User-Agent","NetFox"); @]ydWd  
``?]13XjK  
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int responseCode=httpConnection.getResponseCode(); \k\ {S2SU  
if(responseCode>=400) x*GGO)r  
{ KEF"`VTB@  
processErrorCode(responseCode); *aF#on{  
return -2; //-2 represent access is error ?HT+| !4p  
} /KDKA)  
WK;X6`  
r|2Y|6@  
String sHeader; l1*qDzb  
e<wA["^  
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for(int i=1;;i++) Ce 3{KGBw  
{ c*LB=;npI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fLM5L_S}Y  
//Utility.log(in.readLine());  ~Dvxe  
sHeader=httpConnection.getHeaderFieldKey(i); K,f*}1$qM  
if(sHeader!=null) .}'49=c  
{ 3ZRi@=kWz  
if(sHeader.equals("Content-Length")) t5
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{ ^
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D; xRgHn  
break; -1'O  
} yV`H_iC  
} YC(7k7  
else CJ+/j=i;~c  
break; h"h3SD~  
} kpT>xS^6<  
} 5P=3.Mk  
catch(IOException e){e.printStackTrace ();} iveJh2!#<  
catch(Exception e){e.printStackTrace ();} (I(?oCQ  
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Utility.log(nFileLength); )-yJKmV  
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return nFileLength; er<yB#/;-  
} k@[\C`P  
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wm1`<r^M.  
//保存下载信息（文件指针位置） '
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private void write_nPos() 0PfjD  
{ HW|5'opF  
try{ >4n\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q,pnh!.-c  
output.writeInt(nStartPos.length); FA5|`  
for(int i=0;i<nStartPos.length;i++) <Wd#HKIG>l  
{ B{}<DP.  
// output.writeLong(nPos); j!1 :+H_L  
output.writeLong(fileSplitterFetch.nStartPos); ,|5|aVfh  
output.writeLong(fileSplitterFetch.nEndPos); QMO.Bnek  
} ~PaEhj&8  
output.close(); l\f /(&,  
} nZtMF%j'  
catch(IOException e){e.printStackTrace ();} \kN?7b^  
catch(Exception e){e.printStackTrace ();} exW|c~|m{A  
} xh6Yv%\@  
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//读取保存的下载信息（文件指针位置） oz.#+t%X$b  
private void read_nPos() +8xC%eE  
{ e\8|6<o[  
try{ U# +$N3%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nYFM^56>_  
int nCount = input.readInt(); -eE r|Gs)  
nStartPos = new long[nCount]; Z]~) ->=}  
nEndPos = new long[nCount]; `;~A  
for(int i=0;i<nStartPos.length;i++) I$0O4  
{ Q9G\T:^ury  
nStartPos = input.readLong(); VTUY#+3  
nEndPos = input.readLong();
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} =)c^ik%F&  
input.close(); c1Rn1M,2k  
} EvP\;7B  
catch(IOException e){e.printStackTrace ();} mb\"qD5  
catch(Exception e){e.printStackTrace ();} rv?4S`Z,x$  
} aPToP.e  
@
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private void processErrorCode(int nErrorCode) ;:PxWm|_  
{ d1qvS@  
System.err.println("Error Code : " + nErrorCode); WGwIc7  
} Fp&tJ]=B.  
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yM2}JsC  
//停止文件下载 <B&vfKO^h  
public void siteStop() \\ZCi`O  
{ agGgj>DDd  
bStop = true; #E$*PAB  
for(int i=0;i<nStartPos.length;i++) ?E}9TQ  
fileSplitterFetch.splitterStop(); JP,yRb\  
J#?`l,  
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} JHXtKgFX
 
} k>)Uyw$!  
//负责部分文件的抓取 QOR92}yC  
**FileSplitterFetch.java 5AbY 59  
*/ wnU-5r&!]  
package NetFox; *djVOC  
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import java.io.*; mUNAA[0 L  
import java.net.*; ^WkqRs  
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public class FileSplitterFetch extends Thread { /!'Png0!  
zRMz8IC.  
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String sURL; //File URL wq7h8Z}l  
long nStartPos; //File Snippet Start Position M%YxhuT0  
long nEndPos; //File Snippet End Position ZmDM
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int nThreadID; //Thread's ID 4:=VHd  
boolean bDownOver = false; //Downing is over x=03WQ8  
boolean bStop = false; //Stop identical Z<iK(?@O  
FileAccessI fileAccessI = null; //File Access interface ^4Uk'T7V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException BJt]k7ku+  
{ 7~~suQ{F4  
this.sURL = sURL; %O$=%"D6  
this.nStartPos = nStart; Nwo*tb:  
this.nEndPos = nEnd; PLJDRp 2o  
nThreadID = id; ;\(LovUy6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H;seT X
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} =$y;0]7Lwi  
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}9 ]7V<  
public void run() IF cre  
{ Rk-G|52g  
while(nStartPos < nEndPos && !bStop) h$XoR0  
{ 6!HYx  
r PTfwhs  
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try{ !+z&] S3s  
URL url = new URL(sURL); -Q/wW4dE=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oE_*hp+  
httpConnection.setRequestProperty("User-Agent","NetFox");
8>9MeDE  
String sProperty = "bytes="+nStartPos+"-"; P:WxhO/  
httpConnection.setRequestProperty("RANGE",sProperty); (-],VB (+  
Utility.log(sProperty); r0@s3/  
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InputStream input = httpConnection.getInputStream(); E5#ff5  
//logResponseHead(httpConnection); qnb/zr)p  
@ M4m!;rM  
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byte[] b = new byte[1024]; }(!rB#bf  
int nRead; w5yX~8UzJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |S~$IFN4  
{ iUFG!,+d  
nStartPos += fileAccessI.write(b,0,nRead); P+y XC^ ,  
//if(nThreadID == 1) ArjRoXDE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )w5!'W4Z8  
} ^G 'n z  
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Utility.log("Thread " + nThreadID + " is over!"); lWH#/5`h  
bDownOver = true; 0176  
//nPos = fileAccessI.write (b,0,nRead); Dc* H:x;  
} f~,Ml*Zp  
catch(Exception e){e.printStackTrace ();} AyW=.  
} ]rSg,Q>E  
} cv1PiIl  
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Wsp c;]&  
//打印回应的头信息 t
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public void logResponseHead(HttpURLConnection con) BR-wL3x b  
{ 86 9sS
  
for(int i=1;;i++) zk!7TUZ">w  
{ (74y2U6  
String header=con.getHeaderFieldKey(i); 'r(g5H1}gi  
if(header!=null) 6xAxLZz<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x4MTE?hT  
Utility.log(header+" : "+con.getHeaderField(header)); )#1!%a
Q  
else @
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break; Vugb;5Vl  
} MslgQmlM  
} +Wgfxk'{  
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public void splitterStop() ^16zZ*
 
{ h@'CmIZc  
bStop = true; |lZJt  
} KT*>OYI  
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:bi(mX7t  
} 9[W >`JKo  
4*9t:D|}  
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/* ()w;~$J  
**FileAccess.java qJf\,7m
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*//文件访问(定位，写) 4e;$+!dlV  
package NetFox; ^nN
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import java.io.*; @$ju Qm  
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public class FileAccessI implements Serializable{ 1X`,7B@pz  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lUA-ug! ^  
RandomAccessFile oSavedFile; '*&dP"  
long nPos; O9o]4;  
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public FileAccessI() throws IOException Ctn?O~u  
{ FC6~V6R  
this("",0); S-ZN}N{,6  
} = &?&}pVF  
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1-N+qNSD`  
public FileAccessI(String sName,long nPos) throws IOException Iz'Et'w8!  
{ rnQ_0d  
oSavedFile = new RandomAccessFile(sName,"rw"); J
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this.nPos = nPos; 7:Rt) EE2  
oSavedFile.seek(nPos); z$}9f*W}B  
}
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public synchronized int write(byte[] b,int nStart,int nLen) O6 s3#iu  
{ e8wPEDN*4  
int n = -1; WiB~sIp  
try{ E{e  
oSavedFile.write(b,nStart,nLen); ]];pWlo!  
n = nLen; ]jn1T^D'  
}  qsXkm4  
catch(IOException e) Z!^>!'Z  
{ x{zZ%_F  
e.printStackTrace (); XksI.]tfj  
} L-rV+?i`6f  
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return n; <H-kR\HF  
} ]B3+&g  
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} 8!3q:8y8  
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/* b?Uk%Z]+v  
**SiteInfoBean.java '0)`.  
*/ 4&%H;Q  
package NetFox; &a e!lB  
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+J;b3UE#  
public class SiteInfoBean { bp}97ZQ  
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);}M"W8  
private String sSiteURL; //Site's URL =54D#,[B  
private String sFilePath; //Saved File's Path :<{15:1  
private String sFileName; //Saved File's Name 5lP8#O?=  
private int nSplitter; //Count of Splited Downloading File { pQJ.QI  
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public SiteInfoBean() <pa-C2Ky  
{//nSplitter的缺省值为5 bpU>(j  
//default value of nSplitter is 5 iHf):J?8 y  
this("","","",5); bV2a2#kj  
} `MCtm(<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~,KrL(jC  
{ l
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sSiteURL= sURL; Vj1V;d
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sFilePath = sPath; /F"eqMN  
sFileName = sName; v@SHR0  
this.nSplitter = nSpiltter; \?Z7|  
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} dqQJC qc!  
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public String getSSiteURL() nsXG@CS:  
{ cfv:Ld m  
return sSiteURL; edcz%IOM(  
} Bfo#N31F}  
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3)o>sp)Ji$  
public void setSSiteURL(String value) \4j_K*V  
{ I9aiA
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sSiteURL = value; nVgvn2N/  
} us1$  
2-ksr}
:  
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public String getSFilePath() p$x>I3C(\  
{ `W_&^>yl  
return sFilePath; cV@^<  
} )=#Js<&3:  
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j x< <h_j  
public void setSFilePath(String value) iR{@~JN=)  
{ kCz2uG)l  
sFilePath = value; i?@7>Ca  
} 3Rsrb  
CH!\uK22  
e];IQ|  
public String getSFileName() >$CNR*}@  
{ "%dENK  
return sFileName; tP2.D:( R  
} ` -SC,qHw  
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Y}  
i,Z-UA|f=T  
public void setSFileName(String value) gN(kRhp  
{ <?L5bhq  
sFileName = value; %
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} 5&L*'k
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public int getNSplitter() nZL!}3@<  
{ H=WB6~8)  
return nSplitter; 0;=]MEk?  
} VJW8%s[  
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public void setNSplitter(int nCount) P92pQ_W  
{ ngd4PN>{4  
nSplitter = nCount; )w&|VvM )L  
} d_Zj W  
} =c#mR" 1  
S;8=+I,  
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/* +9t{ovF?L  
**Utility.java ;"9Ks.  
*/ F/tRyq`D  
package NetFox; 48J{Y3F  
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public class Utility { F`,bFQ  
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egfd=z=2un  
public Utility() >k=@YLj  
{ MOB'rPIUI  
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} "av/a  
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//线程睡眠 -\ew,y  
public static void sleep(int nSecond) k!+v*+R+V  
{ X ) =-a  
try{ =R9`to|  
Thread.sleep(nSecond); o?.VW/"  
} Sw[*1C8  
catch(Exception e) -,mV~y  
{ Z~|%asjFE  
e.printStackTrace (); 9v ,y  
} =ty{ugM<  
} B*QLKO:)i  
-I#<?=0B  
//日志 ^tjM1uaZ5(  
public static void log(String sMsg) += gU`<\  
{ y=SpIbn{  
System.err.println(sMsg); Nlc3S+$`z  
}
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!@+4&B=  
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public static void log(int sMsg) O=!EqaExW  
{ O4a~(*f  
System.err.println(sMsg); 8<EU|/O  
} [
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} ?#ywUEY* i  
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.^rsVNG  
/* ?i~mt'O  
**TestMethod.java {qSYe!`  
*/ 5'(#Sf
 
package NetFox; @_;vE(!5  
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public class TestMethod { 2>Kn'p  
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public TestMethod() yfAh=  
{ ///xx/weblogic60b2_win.exe _uk
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try{ M>jk"*hA|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )OQih+#?W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <a D}Ko(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BUla2p  
fileFetch.start(); @Y&(1Wl  
} il:RE8  
catch(Exception e){e.printStackTrace ();} nN[QUg  
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} /JP%gD"8  
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<\\,L@  
public static void main(String[] args) ItQ3|-^  
{ +"[}gss!@  
new TestMethod(); t^<ki?*  
} XZpF<7l  
} ~5_>$7L>  
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