http断点续传简单实现（java)

/* Ei>m0 ~<\  
**SiteFileFetch.java #!J(4tXny  
*/ ^cvl:HOog  
package NetFox; wmr-}Y!9u%  
import java.io.*; 4b]a&_-}  
import java.net.*; %~|HFYd  
"%2xR[NF  
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public class SiteFileFetch extends Thread { 4pz|1Hw7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c8 K3.&P6  
long[] nStartPos; //开始位置 3B0lb"e  
long[] nEndPos; //结束位置 [t]X/O3<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f2)XP$:  
long nFileLength; //文件长度 he3SR@\T  
boolean bFirst = true; //是否第一次取文件 rd|uz4d  
boolean bStop = false; //停止标志 Z^
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File tmpFile; //文件下载的临时信息 bBxw#_3A?E  
DataOutputStream output; //输出到文件的输出流 G`=r^$.3WB  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g\A y`.s  
public SiteFileFetch(SiteInfoBean bean) throws IOException YMpf+kN  
{ \6|/RFT  
siteInfoBean = bean; ,FQdtNMap  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0IM8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "R #k~R  
if(tmpFile.exists ()) woH)0v  
{ =/Aj  
bFirst = false; %T`U^Pnr  
read_nPos(); =wu*D5  
} 5m$2Ku  
else i@"e,7mSG  
{ <pLT'Y=  
nStartPos = new long[bean.getNSplitter()]; gW(gJ; L,%  
nEndPos = new long[bean.getNSplitter()]; {2'm^0Kl  
} Jhkvd<L8`m  
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} Mc sTe|X  
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public void run() *mG`_9  
{ Z5G!ct:W  
//获得文件长度 kQdt}o])  
//分割文件 wz8PtfZ  
//实例FileSplitterFetch }$su4A@0  
//启动FileSplitterFetch线程 OV CR0  
//等待子线程返回 3cl9wWlJ_E  
try{ 1pp -=$k  
if(bFirst) WUdKLx%F  
{ e=P  
nFileLength = getFileSize(); JYqSL)Ta*t  
if(nFileLength == -1) nCg66-3A  
{ m,LG=s  
System.err.println("File Length is not known!"); lEL78l.  
} 01a-{&   
else if(nFileLength == -2) u8
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{ JEn3`B!*  
System.err.println("File is not access!"); rWtZj}A  
} =#5D(0Ab  
else <T?oKOD ]  
{ OqhD7 +  
for(int i=0;i<nStartPos.length;i++) 6V9doP]i  
{ &`|:L(+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); n ?[/ufl  
} Zzua17
 
for(int i=0;i<nEndPos.length-1;i++) &6 -k#r  
{ X##1! ad
 
nEndPos = nStartPos[i+1]; !SOrCMHx  
} eZhPu'id\s  
nEndPos[nEndPos.length-1] = nFileLength; dP$GThGl  
} M s9E@E  
} qgt[~i*  
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//启动子线程 `\>.
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +y+"Fyl  
for(int i=0;i<nStartPos.length;i++) xk~IN%\  
{ &tR(n$M@>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jPvDFT^d/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0:Xxl76v4  
nStartPos,nEndPos,i); n7aU<`U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pI+!92Z  
fileSplitterFetch.start(); !X>=l  
} ~iBgw&Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >>dm}X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tU wRE|_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G>qZxy`c  
nEndPos = " + nFileLength); ".*x!l0y7  
// fileSplitterFetch[nPos.length-1].start(); co4h*?q  
59uwB('|lH  
Y>."3*^  
//等待子线程结束 
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//int count = 0; #(Or|\t  
//是否结束while循环 Id'RL2Kq*&  
boolean breakWhile = false; T<yP* b2E  
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',7??Q7j&v  
while(!bStop) ?VU(Pq*`  
{ oj,lz?  
write_nPos(); FX<b:#  
Utility.sleep(500); }!#gu3  
breakWhile = true; W" "*ASi  
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for(int i=0;i<nStartPos.length;i++) TjK{9A  
{ YKZrEP4^  
if(!fileSplitterFetch.bDownOver) 7)rWw<mY  
{ l7(!`NPbC  
breakWhile = false; !33#. @[  
break; gCd`pi 8  
} `[#x_<\t  
} :m=m}3/:  
if(breakWhile) OIHz I2{  
break; " }gVAAvc7  
:yT-9Ze%q  
$5`!Z%>/  
//count++; +Z2MIC|Ud  
//if(count>4) 3 vP(SIF  
// siteStop(); 5M]z5}n/  
} ek aFN\  
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nq}Q  
System.err.println("文件下载结束！"); `7aDEzmJ  
} y]..=z_ql  
catch(Exception e){e.printStackTrace ();} >C WKH~  
} 5(2|tJw-H;  
"bg'@:4F  
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//获得文件长度 3b'tx!tFN  
public long getFileSize() ~wn
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{ Z{IUy  
int nFileLength = -1; 0rk]/--FGJ  
try{ jcCoan  
URL url = new URL(siteInfoBean.getSSiteURL()); \hO2p6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O/%< }3Sq  
httpConnection.setRequestProperty("User-Agent","NetFox"); fqz28aHh  
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int responseCode=httpConnection.getResponseCode(); G |*(8r()  
if(responseCode>=400) +,+vkpL-%  
{ WE}kTq
  
processErrorCode(responseCode); Hs"(@eDV&J  
return -2; //-2 represent access is error 6TWWlU^e  
} 5/[H+O1;  
u/
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String sHeader; Q0?\]2eet9  
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for(int i=1;;i++) J`M&{UP  
{ |XY
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eC DIwB28  
//Utility.log(in.readLine()); 8GPIZh'0h  
sHeader=httpConnection.getHeaderFieldKey(i); c;f!!3&  
if(sHeader!=null) Z!d7&T}  
{ =+5,B\~q@C  
if(sHeader.equals("Content-Length")) ,?UM;^  
{ 75!9FqMZ}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -${DW^txMZ  
break; +@9gkPQQ-@  
} {P9J8@D  
} e
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else w"m+~).U  
break; 14eW4~Mr  
} os3 8u!3-  
} CDj~;$[B  
catch(IOException e){e.printStackTrace ();} C#rc@r,F  
catch(Exception e){e.printStackTrace ();} JE5  
;^ wd_  
{n3EGSP#  
Utility.log(nFileLength); uy_wp^  
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return nFileLength; xVB;s.'!  
} {3a&1'a0g  
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//保存下载信息（文件指针位置） aIy*pmpD=  
private void write_nPos() kB:Uu}(=N  
{ S 6,4PP  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); Z#d&|5Xj  
output.writeInt(nStartPos.length); ?rVy2!  
for(int i=0;i<nStartPos.length;i++) eO=s-]mk  
{ h+.{2^x  
// output.writeLong(nPos); <^.=>Q0S\  
output.writeLong(fileSplitterFetch.nStartPos); a/Q$cOs  
output.writeLong(fileSplitterFetch.nEndPos); qL$a c}`  
} :nHKl  
output.close(); /StTb,  
} 5FVndMM#y  
catch(IOException e){e.printStackTrace ();} :%&Q-kk4!  
catch(Exception e){e.printStackTrace ();} M69 w-  
} vD/NgRBww  
nL@KX>  

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//读取保存的下载信息（文件指针位置） W+wA_s2&D  
private void read_nPos() zQ?!f#f  
{ 'mCe=Y  
try{ 2=0DCF;Bv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A,-6|&F  
int nCount = input.readInt(); ;a=w5,h:  
nStartPos = new long[nCount]; ?PA$Ur21lw  
nEndPos = new long[nCount]; _!;Me )C  
for(int i=0;i<nStartPos.length;i++) 1Q;}zHd  
{ U/ V  
nStartPos = input.readLong(); {%)s.5Pfw  
nEndPos = input.readLong(); [%~ :@m  
} UsGa  
input.close(); 5wB =>  
} [L`ZE*z  
catch(IOException e){e.printStackTrace ();} 0C<[9Dl.G8  
catch(Exception e){e.printStackTrace ();} >FjR
9B  
} 7qOa ;^T  
6%`&+Lq  
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private void processErrorCode(int nErrorCode) #1c]PX  
{ vr#+0:|  
System.err.println("Error Code : " + nErrorCode); -&82$mj  
} T J^u"j-'  
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//停止文件下载 V6$xcAE"</  
public void siteStop() 0`.
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{ ^m#-9-`  
bStop = true; R_]{2~J+  
for(int i=0;i<nStartPos.length;i++) iUMY!eqp  
fileSplitterFetch.splitterStop(); K/m3  
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?7:KphFX)  
} mS>xGtD&K  
} -aRU]kIf  
//负责部分文件的抓取 :.(;<b<\  
**FileSplitterFetch.java OJT1d-5p  
*/ YzosZ! L!<  
package NetFox; dpQG[vXe  
{ pu85'DV  
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import java.io.*; V^y^ ;0I}[  
import java.net.*; ')a(.f  
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public class FileSplitterFetch extends Thread { jA".r'D%  
ZnFi<@UB)  
}nt* [:%  
String sURL; //File URL wIkN9 f  
long nStartPos; //File Snippet Start Position }(a+aHH  
long nEndPos; //File Snippet End Position O/:UJ( e{  
int nThreadID; //Thread's ID )%rg?l
I  
boolean bDownOver = false; //Downing is over G;> _<22  
boolean bStop = false; //Stop identical T|&[7%F3"  
FileAccessI fileAccessI = null; //File Access interface PFUO8>!pA\  
}:: S0l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5<
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{ _X~87  
this.sURL = sURL; 86@c't@  
this.nStartPos = nStart; 3mPjpm  
this.nEndPos = nEnd; :^UFiUzrE  
nThreadID = id; 'c\iK
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 I%|>2}-_U  
} ntNI]~z&  
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f= >OJ!:  
public void run() (SSRY9  
{ N@B9 @8h  
while(nStartPos < nEndPos && !bStop) r"$.4@gc  
{ .xf<=ep  
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try{ (}.@b|s  
URL url = new URL(sURL); MO;X>D=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kq\)MQ"/X  
httpConnection.setRequestProperty("User-Agent","NetFox"); .CP&bJP%  
String sProperty = "bytes="+nStartPos+"-"; m*e{\)rd#  
httpConnection.setRequestProperty("RANGE",sProperty); zy*/T>{#  
Utility.log(sProperty); -}K<ni6  
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InputStream input = httpConnection.getInputStream(); rD>*j~_+P  
//logResponseHead(httpConnection); !w BJ,&E  
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h
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byte[] b = new byte[1024]; $d?.2Kg  
int nRead; ;?C#IU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9@Cv5L?p\  
{ bINvqv0v  
nStartPos += fileAccessI.write(b,0,nRead); d1[ZHio2c?  
//if(nThreadID == 1) +r3IN){jz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8[6o (  
} y qtKy  
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= k\J<  
Utility.log("Thread " + nThreadID + " is over!"); :qC'$dO!
 
bDownOver = true; r1RGTEkD  
//nPos = fileAccessI.write (b,0,nRead); 1CLL%\V  
} 5n
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catch(Exception e){e.printStackTrace ();} {Ay"bjZh  
} P2Vg4   
} f6$b s+oP  
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//打印回应的头信息 .s$
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public void logResponseHead(HttpURLConnection con) D7_*k%;@  
{ 8,dBl!G=  
for(int i=1;;i++) O12eH  
{ g+X}c/".  
String header=con.getHeaderFieldKey(i); A 7[:5$  
if(header!=null) 'vNG(h#%d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )8
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Utility.log(header+" : "+con.getHeaderField(header)); A$6$,h  
else \d::l{VB  
break; @JdZ5Q  
} }1IpON  
} `({T]@]V  
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public void splitterStop() S*yjee<@  
{ BT}&Y6  
bStop = true; eYx Kp!f  
} ,@5I:X!rR  
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} m.,U:>  
I!^O)4QRx  
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/* [` sL?&a  
**FileAccess.java #:SNHM^><  
*//文件访问(定位，写) Y`?-VaY  
package NetFox; Agrk|wPK  
import java.io.*; \6\<~UX^  
qP<Lr)nUH  
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public class FileAccessI implements Serializable{ @IXsy  
->N8#XH2=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zXRlo]  
RandomAccessFile oSavedFile; /hO1QT}xd  
long nPos; 0Fu~
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public FileAccessI() throws IOException '(/7[tJ  
{ yr,=.?C-  
this("",0); {s;U~!3aY  
} 3do)Vg4  
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public FileAccessI(String sName,long nPos) throws IOException Kv~U6_=1O  
{ _o8?E&d  
oSavedFile = new RandomAccessFile(sName,"rw"); 4
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this.nPos = nPos; J`2"KzR0w"  
oSavedFile.seek(nPos); )m. 4i=X  
} 7B?c{  
~y7jCcd`  
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public synchronized int write(byte[] b,int nStart,int nLen) K<>sOWZ'S  
{ Vx-7\NB  
int n = -1; =G]@+e  
try{ Dih3}X&jn$  
oSavedFile.write(b,nStart,nLen); {AQ=<RDRF  
n = nLen; #Qkroji qw  
} U,LTVYrO  
catch(IOException e) %;D.vKoh  
{ `jOX6_z?I  
e.printStackTrace (); P
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} i7ly[6{^pr  
VH:]@x//{  
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return n; #^]n0!  
} +zs4a96[  
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} V(E/'DR  
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+sJrllrE(  
/* zen*PeIrA^  
**SiteInfoBean.java [ Fz`D/  
*/ 4!wR_@W^El  
package NetFox; MuSUKBh
M  
M %Qt|@O  
 E6WA}_  
public class SiteInfoBean { wm^J;<T[  
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2;?I>~  
private String sSiteURL; //Site's URL )YqXRm  
private String sFilePath; //Saved File's Path T'~!9Q  
private String sFileName; //Saved File's Name Mec5h}^  
private int nSplitter; //Count of Splited Downloading File [n/hkXa$\  
bAx?&$  
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public SiteInfoBean() OD_W8!-  
{//nSplitter的缺省值为5 QeK*j/  
//default value of nSplitter is 5 @62Mk},9 c  
this("","","",5); l(Q?rwI8Y  
} KSrx[q  
?y!E-&  
95
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Zcc9e03  
{ hh[jN7K  
sSiteURL= sURL; x@Hc@R<!  
sFilePath = sPath; )[Yv?>ib  
sFileName = sName; 2rZxSg  
this.nSplitter = nSpiltter; ,tg0L$qC  
-(bkr+N  
<Z/x,-^*<  
} r4#o+qE  
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public String getSSiteURL() .AU)*7Gh  
{ ',S'.U  
return sSiteURL; JGQjw(Xs  
} *H|M;G  
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public void setSSiteURL(String value) &sd}ulEg`  
{ G}G#i`6o  
sSiteURL = value; j.@\3'  
} ,#kIr  
pt}X>ph{  
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public String getSFilePath() (zFi$  
{ k Zq!&  
return sFilePath; &EnuE0BD  
} ^) s2$A:L  
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public void setSFilePath(String value) s91JBP|B7  
{ icgSe:Ci  
sFilePath = value; F
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} }:~x7|~s:  
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public String getSFileName() ih;]nJ]+-  
{ ,1"KHv  
return sFileName; _"w2Uq  
} "l*`>5Nn9  
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` 5C~  
public void setSFileName(String value) D=
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{ ,kn">k9  
sFileName = value; 'u1?tQ=gmk  
} Ez-[ )44/  
2]ape !(  
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public int getNSplitter() go<W(
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{ >lIk9|  
return nSplitter; PxS8 n?y  
} !dC<4qZ\C  
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public void setNSplitter(int nCount) B[4KX  
{ .8G@%p{,  
nSplitter = nCount; 5EebPXBzB  
} v3jg~"!  
} $"H{4x`-  
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])!o5`ltZ  
/* a0ObBe'
  
**Utility.java ;{"+g)u  
*/ KPj\-g'A  
package NetFox; =HlQ36;*  
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!f+H,]D"  
public class Utility { 9amaL~m  
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public Utility() gjAIEI  
{ xsMBC  
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} Uh):b%bS;J  
9 o&`5  
//线程睡眠 rq/I` :  
public static void sleep(int nSecond) fL=~N
C"  
{ 9Q+'n$s0^  
try{ la+[bm<v  
Thread.sleep(nSecond); SrK)t.oK  
} 8{X"h#  
catch(Exception e) 3^6 d]f  
{ k-{<=>uM  
e.printStackTrace (); sH[ROm  
} u!W0P6   
} M%kO7>h8  
Oz%>/zw[h
 
//日志 X'qU*Eo  
public static void log(String sMsg) jmFz51  
{ l|k`YC x  
System.err.println(sMsg); z\%Ls   
} e8#h3lxJ`  
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F ;2w1S^  
public static void log(int sMsg) cj'}4(  
{ ]n~ilS.rkl  
System.err.println(sMsg); ~"k
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} 7*Ej.
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} j+,d^!  
@-!}BUs?  
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/* 65aK2MS@  
**TestMethod.java !74S  
*/ @6]sNm  
package NetFox; L$E{ycn
  
8Hn|cf0  
#ka
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public class TestMethod { @dPTk"P  
y3o25}"  
io{@^1ab  
public TestMethod() z-.+x3&o @  
{ ///xx/weblogic60b2_win.exe 6U R2IxbE  
try{ [c|]f_ZdK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +w{*Xk)4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \S!e![L/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wlqpn(XR  
fileFetch.start(); ''\O
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} Dw<bn<e-  
catch(Exception e){e.printStackTrace ();} SX# e:_  
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=aBctd:eX`  
} ne_TIwfw-  
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public static void main(String[] args) Ke2ccN  
{ [VsKa\9u  
new TestMethod(); HTS%^<u  
} [8*jw'W|[  
} ^!<BQP7  
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