http断点续传简单实现（java)

/* +.|8W!h`1  
**SiteFileFetch.java {3G2-$yb  
*/ _j?/O)M c  
package NetFox; q&V=A[<rz  
import java.io.*; _;u@xl=  
import java.net.*; |r/4 ({n  
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public class SiteFileFetch extends Thread { K2ry@haN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /Avl&Rd  
long[] nStartPos; //开始位置 T^.W'  
long[] nEndPos; //结束位置 Y?V>%eBu  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gfU!sYZ  
long nFileLength; //文件长度 1}jwv_0lL  
boolean bFirst = true; //是否第一次取文件 `+EjmY  
boolean bStop = false; //停止标志 < c[dpK5c  
File tmpFile; //文件下载的临时信息 ewv[nJD$  
DataOutputStream output; //输出到文件的输出流 H8?Kgaj~vf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） L }&$5KiwV  
public SiteFileFetch(SiteInfoBean bean) throws IOException \!,qXfTMB  
{ ypsT:uLT  
siteInfoBean = bean; *8j2iu-|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3bPF+(`J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mdPEF)-  
if(tmpFile.exists ()) Dl95Vo=1  
{ gTwxmp.,  
bFirst = false; Oj^qh+r  
read_nPos(); i-_ * 5%A  
} :Vx5%4J  
else $r87]
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{ Vpsv@\@J>  
nStartPos = new long[bean.getNSplitter()]; q/HwcX+[b  
nEndPos = new long[bean.getNSplitter()]; x"Q
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} q+Cq&|4 ?2  
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} NM_Xy<.~E  
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public void run() ^E(:nxQ6s  
{ O$,MdhyXC  
//获得文件长度 f]Q`8nU  
//分割文件 D!d1%hac  
//实例FileSplitterFetch D<d4"*qo  
//启动FileSplitterFetch线程 zs~v6y@  
//等待子线程返回 yq2pg8%  
try{ }{.0mu9  
if(bFirst) xLmgr72D  
{ >=Pn\"j  
nFileLength = getFileSize(); YXr"  
if(nFileLength == -1) d`+@ _)ea  
{ Gn8'h TM  
System.err.println("File Length is not known!"); yMoV|U6  
} +__PT4ps  
else if(nFileLength == -2) oX #WT  
{ o6[aP[~F  
System.err.println("File is not access!"); M'D l_dx-  
} zZax![Z  
else b,Vg3BS  
{ #7}1W[y9}l  
for(int i=0;i<nStartPos.length;i++) @ysc?4% q  
{ (6Tvu
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); 88l\8k4r  
} 9$[PAjwk  
for(int i=0;i<nEndPos.length-1;i++) :K)7_]y  
{ Qmg2lP.)  
nEndPos = nStartPos[i+1]; Fb0r(vQ^  
} GWvw<`4  
nEndPos[nEndPos.length-1] = nFileLength; 4,]z  
} -0>gq$/N=^  
} (rfR:[JkC2  
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//启动子线程 <lo\7p$A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0Kytg\p}  
for(int i=0;i<nStartPos.length;i++) nR(v~_y[V  
{ L]kd.JJvy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DQ*T2*L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =+z+`
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nStartPos,nEndPos,i);  nLD1j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G=ly .  
fileSplitterFetch.start(); rn9n_)  
} ("r\3Mvs  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $~+(si2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6Lb(oY}\3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @/,:"
. SM  
nEndPos = " + nFileLength); [Xyu_I-c  
// fileSplitterFetch[nPos.length-1].start(); rLpfybu  
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//等待子线程结束 cTJi8f=g  
//int count = 0; -Lhq.Q*a  
//是否结束while循环 DEw>f%&4  
boolean breakWhile = false; 'EHtA9M  
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while(!bStop) 2rV]n  
{ , UsY0YC  
write_nPos(); g2;lEW  
Utility.sleep(500); cE;n>ta"F  
breakWhile = true; mPL0s  
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for(int i=0;i<nStartPos.length;i++) lz7?Z  
{ S"4eS,5L|  
if(!fileSplitterFetch.bDownOver) .0Kc|b=w  
{ awv$ }EFo  
breakWhile = false; jQrj3*V  
break; )Yu  
} -|GKtZ]}  
} w*M&@+3I  
if(breakWhile) $<QrV,T  
break; \$4 [qG=  
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//count++; @-ml=S7;Sz  
//if(count>4) 1Q/=s,{u  
// siteStop(); !-t,r%CG  
} JC MUK<CG  
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System.err.println("文件下载结束！"); p0[+Zm{#l  
} .
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catch(Exception e){e.printStackTrace ();} ^TtL-|I  
} {Q}F.0Q  
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//获得文件长度 o! l Ykud  
public long getFileSize() uzI=.j  
{ L#",.x  
int nFileLength = -1; RfO
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try{ gBky
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URL url = new URL(siteInfoBean.getSSiteURL()); Mj{w/'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %q}[ZD/HD  
httpConnection.setRequestProperty("User-Agent","NetFox"); WfD fj  
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! ,bQ;p3g|  
int responseCode=httpConnection.getResponseCode(); n)~*B
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if(responseCode>=400) f S[-K?K  
{ /O5&)%N  
processErrorCode(responseCode); |UlG@Mn  
return -2; //-2 represent access is error Wqkb1~]#Y  
} \{}dn,?Fv  
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String sHeader; {l)$9!  
[ /YuI@C,@  
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for(int i=1;;i++) 43pe6 ^.  
{ 3 3|t5Ia  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (-g*U#  
//Utility.log(in.readLine()); e{7\pQK  
sHeader=httpConnection.getHeaderFieldKey(i); L;* s-j6y  
if(sHeader!=null) SIV !8mz  
{ *I)J%#  
if(sHeader.equals("Content-Length")) ]q.%_  
{ X%
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J Cq>;br.  
break; bx(@ fl:m  
} 6q\*{_CPB  
} GPGE7X'  
else {$,\Qg  
break; ~%8P0AP  
} 1!KROes4  
} Oj;*Gi9E  
catch(IOException e){e.printStackTrace ();} ;U|(rM;  
catch(Exception e){e.printStackTrace ();} pY`$k#5  
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Utility.log(nFileLength); ,\s`T O  
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return nFileLength; st;i
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} wX0D^)NtF  
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//保存下载信息（文件指针位置） rXi&8R[  
private void write_nPos() 3'Y-~^ml|  
{ &t^*0/~  
try{ pM?~AYWb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =mO5~~"W+v  
output.writeInt(nStartPos.length); z'U.}27&o  
for(int i=0;i<nStartPos.length;i++) ]~aj  
{ taE p   
// output.writeLong(nPos); uQIPnd(V  
output.writeLong(fileSplitterFetch.nStartPos); B/wD~xC?x  
output.writeLong(fileSplitterFetch.nEndPos); 
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} 509T?\r  
output.close(); `eMZhYo  
} ENZym
  
catch(IOException e){e.printStackTrace ();} MY,~leP&  
catch(Exception e){e.printStackTrace ();} cXPpxRXBD  
} A|\A|8=b  
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//读取保存的下载信息（文件指针位置） M-nRhso  
private void read_nPos() qWhW4$7x  
{
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try{ ZaYiby@Ci  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SE+hB  
int nCount = input.readInt(); zR<{z  
nStartPos = new long[nCount]; X5iD<Lh  
nEndPos = new long[nCount]; NftnbsTmy  
for(int i=0;i<nStartPos.length;i++) EHwb?{  
{ .o/|]d`%  
nStartPos = input.readLong(); yMNJHiE/  
nEndPos = input.readLong(); dHDtY$/_  
} h-96 2(LG  
input.close(); _<(xjWp 8  
} G`!,
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catch(IOException e){e.printStackTrace ();} ?{ )'O+s  
catch(Exception e){e.printStackTrace ();} I6^y` 2X  
} nLm'a_  
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private void processErrorCode(int nErrorCode) NCKR<!(  
{ ArtY;.cg%  
System.err.println("Error Code : " + nErrorCode); `j{3|C=  
} -dM~3'  
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//停止文件下载 c +]r  
public void siteStop() >GIQT?O6  
{ k{f1q>gd  
bStop = true; r ~{nlLO}  
for(int i=0;i<nStartPos.length;i++) &u:U"j  
fileSplitterFetch.splitterStop(); (f&V 7n  
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} ;j T{< Y  
} N6[Z*5efR  
//负责部分文件的抓取 ~aotV1
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**FileSplitterFetch.java Kh3i.gm7g  
*/ |KJGM1]G  
package NetFox; C/!P&`<6  
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import java.io.*; OFohyy(  
import java.net.*; 5
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public class FileSplitterFetch extends Thread { (1=@.srAzK  
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String sURL; //File URL htYfIy{5w  
long nStartPos; //File Snippet Start Position HHx5VI  
long nEndPos; //File Snippet End Position `V/kM0A5  
int nThreadID; //Thread's ID |$tF{\  
boolean bDownOver = false; //Downing is over .\`MoH  
boolean bStop = false; //Stop identical c*owP  
FileAccessI fileAccessI = null; //File Access interface  \&d1bq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "X<V>q$0~c  
{ 7IUJHc?  
this.sURL = sURL; "S@]yL  
this.nStartPos = nStart; Zq{gp1WC  
this.nEndPos = nEnd; ^Cp;#|g,  
nThreadID = id; N8T.Ye N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Uv
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} *r4FOA%P  
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public void run() Eb,M+c?  
{ /?>W\bP<  
while(nStartPos < nEndPos && !bStop) 2x gk$E$7  
{ 2kgSIvk\  
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try{ >8NUji2I  
URL url = new URL(sURL); Yi-,Pb?   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); auB+g'l  
httpConnection.setRequestProperty("User-Agent","NetFox"); :MYLap&L&  
String sProperty = "bytes="+nStartPos+"-"; 4tkb7D q  
httpConnection.setRequestProperty("RANGE",sProperty); t.!?"kP"c  
Utility.log(sProperty); 3W[||V[r]<  
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InputStream input = httpConnection.getInputStream(); a U<+ `  
//logResponseHead(httpConnection); zl, Vj%d  
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byte[] b = new byte[1024]; tPk>hzW  
int nRead; K=4|GZ~p}`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Eb'M< ZY  
{ OgK' ~j  
nStartPos += fileAccessI.write(b,0,nRead); 29z@ !  
//if(nThreadID == 1) HKC&grp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cI6Td*vM  
} 1k%HGQM{  
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Utility.log("Thread " + nThreadID + " is over!"); 
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bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); H.Z<T{y;  
} D;:p6q}hT  
catch(Exception e){e.printStackTrace ();} Yi`DRkp]3  
} iII%!f?{[  
} X=jD^"-  
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{XXnMO4uR;  
//打印回应的头信息 %4wHiCOg  
public void logResponseHead(HttpURLConnection con) j\@&poJ(,  
{ LCSJIt  
for(int i=1;;i++) -|:mRAe  
{ s?9`dv}P  
String header=con.getHeaderFieldKey(i); \Jwc[R&x  
if(header!=null) sZ"(#g;3<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xd`\Ai  
Utility.log(header+" : "+con.getHeaderField(header)); 2p*!up(  
else Kciz^)'Z  
break; VTO92Eo  
} ;6=*E'  
} k]c$SzJ>/  
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public void splitterStop() EQy~ ^7V B  
{ OL.{lKJ3DV  
bStop = true; *"V) hI5  
} rLp0)Go  
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} &<(&u`S  
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u} [.*e  
/* Jn\>Sz(96  
**FileAccess.java 
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*//文件访问(定位，写) Vzh\1cF  
package NetFox; |-]'~@~  
import java.io.*; DH])Q5  
4@jX{{^6%  
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public class FileAccessI implements Serializable{ 5QG?*Z~?7  
A ?[Wfq|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (I#3![q  
RandomAccessFile oSavedFile; :>3?|Z"Aj  
long nPos; *3(mNpi{_  
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public FileAccessI() throws IOException r_Pi)MPc  
{ ]&"01M~+K  
this("",0); nCLEAe$W\=  
} kq>I?wg  
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public FileAccessI(String sName,long nPos) throws IOException 0>ce~KU  
{ %vRCs]  
oSavedFile = new RandomAccessFile(sName,"rw"); dM;v39  
this.nPos = nPos; T@ zV   
oSavedFile.seek(nPos); {Lsl2@22  
} [I( Yn  
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` c"  
public synchronized int write(byte[] b,int nStart,int nLen) Ed1y%mR>  
{ Oh,]"(+  
int n = -1;  =tc!"{  
try{ 2CV?cm  
oSavedFile.write(b,nStart,nLen); R|]n;*y  
n = nLen; jaQH1^~l/-  
} 5I/lFoy7  
catch(IOException e) ULzrJbP'7  
{ $-paY
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e.printStackTrace (); KESM5p"f  
} pL2{zW`FDh  
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return n; pz]!T'  
} y N,grU(  
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} JgBC:t^\pV  
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/* ]#vi/6\J  
**SiteInfoBean.java Qw<&N$  
*/ x7/";L>  
package NetFox; @]Lu"h#u=  
[OR"9W&  
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public class SiteInfoBean { \susLD  
\;JZt[  
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private String sSiteURL; //Site's URL "egpc*|]  
private String sFilePath; //Saved File's Path <jBRUa[j_  
private String sFileName; //Saved File's Name ]`M2Kwp  
private int nSplitter; //Count of Splited Downloading File e9>~mtx  
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public SiteInfoBean() I+ Y{_yw"f  
{//nSplitter的缺省值为5 ],Yy)<e.  
//default value of nSplitter is 5 /*MioaQB}p  
this("","","",5); =nqHVRA  
} .br6x^\<  
[v`kqL~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qw{`?1[+  
{ 1xInU_SPf  
sSiteURL= sURL; \>X!n2rLZe  
sFilePath = sPath; h`iOs>  
sFileName = sName; m"QDc[^Ge  
this.nSplitter = nSpiltter; lc3Gu78 A/  
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+}PN+:yV  
} `evF?t11X  
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public String getSSiteURL() :Qhrh(i  
{ Nd&UWk^  
return sSiteURL; 9zY6hh**  
} P^tTg  
2=/-,kOL_  
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public void setSSiteURL(String value) 5{Q9n{dOh  
{ >H ?k0M`L  
sSiteURL = value; 52zE -SY  
} e[s}tjx  
*l=(?Pe<  
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public String getSFilePath() @bJIN]R  
{ zo8D"  
return sFilePath; uxB`  
} imeE&  
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public void setSFilePath(String value)
|<5F08]v  
{ _TGs .t  
sFilePath = value; CS~_>bn  
} CH&{x7$he  
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public String getSFileName() ][ IOlR  
{ 40pz<-B  
return sFileName; &T~X`{V]`  
} &lLfVa-l  
28`s+sH  
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public void setSFileName(String value) !ltq@8#_|  
{ YO$D-  
sFileName = value; <|jh3Hlp  
} w.a9}GC  
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public int getNSplitter() .<F46?HS  
{ bXO
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return nSplitter; yV )fJ_  
} tP7<WGHd/  
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public void setNSplitter(int nCount) ?'z/S5&j  
{ BB\GrD  
nSplitter = nCount; [Hx(a.,d  
} ekL
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} nOvR, 6  
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9<.O=-1~  
/* 3Iv^  
**Utility.java .R)P |@z L  
*/ H3<tsK=:  
package NetFox; YM:sLeQ~c  
8qg%>ZU4d  
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public class Utility { t{jY@JT|  
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public Utility() 1vj@qw3  
{ ~p?A
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} 0BlEt1e2T  
BZ?3=S1*  
//线程睡眠 BX0lk  
public static void sleep(int nSecond) ^EX"fRwNi  
{ r6Yd"~
n  
try{ e=OHO,74z"  
Thread.sleep(nSecond); .
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} @/.# /  
catch(Exception e) ZyUcL_  
{ ='o3<}  
e.printStackTrace (); BqNeY<zB*  
} SWV*w[X<X  
} pD%(Y^h?  
iH }-  
//日志 \dtiv&x  
public static void log(String sMsg) 1RYrUg"s"  
{ e.n(NW  
System.err.println(sMsg); ~i5YqH0  
} z3+@[I$  
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public static void log(int sMsg) n^4R]9U  
{ qgrJi +WZ  
System.err.println(sMsg); =9jK\ T^  
} GEWjQ;g  
} ."$t&[;s  
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/* *U[y
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.  
**TestMethod.java oFWb.t9<  
*/ XDemdMy$  
package NetFox; %qoS(iO`h  
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public class TestMethod { )\akIA  
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7)lEZJK&T  
public TestMethod() tqGrhOt  
{ ///xx/weblogic60b2_win.exe @sXv5kZ
:  
try{ _ox+5?>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j7~FR{:j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YMX9Z||  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "hsT^sy  
fileFetch.start(); .e~"+Pe6b  
} 3Z b]@n  
catch(Exception e){e.printStackTrace ();} VzP az\e  
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} 3:+9H}Q  
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public static void main(String[] args) yKc-:IBb{u  
{ |6E_N5~  
new TestMethod(); Pxlc RF  
} r]3-}:vU  
} Ir9GgB  
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