http断点续传简单实现（java)

/* ^'|\8  
**SiteFileFetch.java xCd9b:jG  
*/ 0-^wY8n-=  
package NetFox; dD2N!umW  
import java.io.*;
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import java.net.*; YJO,"7+  
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public class SiteFileFetch extends Thread { o.}?K>5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'ErtiD  
long[] nStartPos; //开始位置 (\si/&  
long[] nEndPos; //结束位置 fU+A~oL%I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .g7ebh6D  
long nFileLength; //文件长度 `NC{+A  
boolean bFirst = true; //是否第一次取文件 p[QF3)9F  
boolean bStop = false; //停止标志 su`]l"[,]  
File tmpFile; //文件下载的临时信息 .>-`2B*/  
DataOutputStream output; //输出到文件的输出流 GB+U>nf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R,hX *yVq  
public SiteFileFetch(SiteInfoBean bean) throws IOException NC 0H5  
{ xi6Fs, 2S  
siteInfoBean = bean; l
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9oteQN{9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $+Hv5]/hb  
if(tmpFile.exists ()) 5Dy800.B2  
{ ~%
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bFirst = false; >mT< AQ  
read_nPos();  KUfk5Y  
} :;u~M(R  
else 2w=0&wG4K  
{ x@I@7Pvo3  
nStartPos = new long[bean.getNSplitter()]; W"mkNqH  
nEndPos = new long[bean.getNSplitter()]; %$ ^yot  
} Te"<.0~1  
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,/\%-u? 1x  
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} :8;8-c  
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public void run() jZ<
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{ BZqb o`9  
//获得文件长度 *xs8/?  
//分割文件 ~BVg#_P  
//实例FileSplitterFetch ]?L?q2>&  
//启动FileSplitterFetch线程 <3;/,>^ Pm  
//等待子线程返回 HFwT  
try{ Aa&3x~3+  
if(bFirst) z(^p@&r)F  
{ V#W(c_g
 
nFileLength = getFileSize(); TA=Ij,z~  
if(nFileLength == -1) ,\5]n&T;r  
{ ?-O(EY1E  
System.err.println("File Length is not known!"); ^/HE_keY  
} 7581G$@ym  
else if(nFileLength == -2) (tEW#l'}  
{ KM|[:v  
System.err.println("File is not access!"); S<Q6b_D  
} J#CF SG
  
else w
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{ nTjQ4y  
for(int i=0;i<nStartPos.length;i++) .1MXQLy  
{ EOV<|WF>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =o=)EU{~  
} p/WEQ2  
for(int i=0;i<nEndPos.length-1;i++) @4_CR  
{ &l%#OI}OE  
nEndPos = nStartPos[i+1]; 4EuZe:'X  
} u~?]/-.TY  
nEndPos[nEndPos.length-1] = nFileLength; $g#j,  
} dL")E|\\k  
} (@`+Le  
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//启动子线程 _y`'T;~OY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A0S6 4(  
for(int i=0;i<nStartPos.length;i++) 94W9P't  
{ -4b9(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yc#oGCt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XaD}J:Xq  
nStartPos,nEndPos,i); BZsw(l4/0'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bn^^|i  
fileSplitterFetch.start(); Lm'Ony^F  
} &&[j/d}J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~@R=]l"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %@*diJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hdN3r{  
nEndPos = " + nFileLength); yq[C?N &N  
// fileSplitterFetch[nPos.length-1].start(); U,Z.MPQ  
TA}gCXE e  
*8"5mC;"  
//等待子线程结束 @q5!3Nz  
//int count = 0; NK*~UePy  
//是否结束while循环 HI']{2p2}t  
boolean breakWhile = false; &#g;=jZ  
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while(!bStop) LtH;#Q  
{ Yk<?HNf  
write_nPos(); &e_M
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Utility.sleep(500); (q*T.  
breakWhile = true; V|xR`Q  
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for(int i=0;i<nStartPos.length;i++) 6}Y^X  
{ K*;
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if(!fileSplitterFetch.bDownOver) X"8Jk4y  
{ tTF/$`Q#*  
breakWhile = false; )1J&tV*U  
break; !=cW+=1  
} F:IG3 @  
} HnioB=fc  
if(breakWhile) O|%><I?I  
break; &hd+x5  
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r6 ,5&`&  
//count++; q(!191@C(  
//if(count>4) 7Y@&&  
// siteStop(); kHX- AsRc  
} 5@O
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System.err.println("文件下载结束！"); vYmRW-1Zxq  
} FL0(q>$*8  
catch(Exception e){e.printStackTrace ();} $+S'Boo  
} l4hC>q$T  
'!{zO" 1*  
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//获得文件长度 E n{vCN  
public long getFileSize() eNu`\  
{ tQz-tQg  
int nFileLength = -1; N\HOo-X  
try{ RH6qi{)i!  
URL url = new URL(siteInfoBean.getSSiteURL()); 98Pt&C?-B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a,M7Bbx  
httpConnection.setRequestProperty("User-Agent","NetFox"); RjSVa.x  
~;il{ym  
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int responseCode=httpConnection.getResponseCode(); "
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if(responseCode>=400) <d$|~qS_  
{ LurBqr  
processErrorCode(responseCode); h&[]B*BLr  
return -2; //-2 represent access is error N!/^s":  
} z930Wi{@  
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String sHeader; Skp&W*Ai  
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for(int i=1;;i++) *hAq]VC})  
{ VoWlBH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^l7u^j
  
//Utility.log(in.readLine()); 4[Hf[.  
sHeader=httpConnection.getHeaderFieldKey(i); qL,!
 
if(sHeader!=null) \@GA;~x.b  
{ :=T+sT~  
if(sHeader.equals("Content-Length")) &JtK<g  
{ -+#\WB{AI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 29 Yg>R!/  
break; ^yu0Veypy  
} ~H7m7  
} .1[K\t)
2  
else (.m0hN!~u  
break; m:)v>vu  
} DZilK:  
} "S_t%m&R  
catch(IOException e){e.printStackTrace ();} ygWo9?  
catch(Exception e){e.printStackTrace ();} oOmPbAY  
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Utility.log(nFileLength); 2u*o/L+  
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return nFileLength; I|n<B"Q6^  
} @i$9c)D  
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//保存下载信息（文件指针位置） 0}PW<lU-  
private void write_nPos() (
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{ -s,^_p{H  
try{ !G90oW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tl (2=\  
output.writeInt(nStartPos.length); KArR.o }  
for(int i=0;i<nStartPos.length;i++) '_@Y  
{ 5nkx8JJ  
// output.writeLong(nPos); >hJ$~4?  
output.writeLong(fileSplitterFetch.nStartPos); |K,9EM
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output.writeLong(fileSplitterFetch.nEndPos); fJH09:@^%  
} $[by)  
output.close(); B=jJ+R  
} ic%<
39  
catch(IOException e){e.printStackTrace ();} +5JCbT@y  
catch(Exception e){e.printStackTrace ();} nws '%MK)  
} l|/h4BJ'  
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G{

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//读取保存的下载信息（文件指针位置） m$NBGw  
private void read_nPos() P|!GXkS  
{ `kpX}cKK}  
try{ X2}\i5{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 68[3 /  
int nCount = input.readInt(); \j+O |#`|)  
nStartPos = new long[nCount]; +%OINMo.A  
nEndPos = new long[nCount]; O={4 >>F  
for(int i=0;i<nStartPos.length;i++) \3-XXq  
{ JN .\{ Y  
nStartPos = input.readLong(); +?w 7Nm`  
nEndPos = input.readLong(); TUw^KSa  
} m$ )yd~  
input.close(); }/n
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}
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catch(IOException e){e.printStackTrace ();} ] QGYEjW  
catch(Exception e){e.printStackTrace ();} wc*5s7_  
} j&6,%s-M`a  
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private void processErrorCode(int nErrorCode) '
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{ &Gp@,t  
System.err.println("Error Code : " + nErrorCode); A[ 9 @:z  
} W2D^%;mw  
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//停止文件下载 =Mzg={)v  
public void siteStop() g{.>nE^Sc5  
{ l"5$6h  
bStop = true; s:'M[xI  
for(int i=0;i<nStartPos.length;i++) ZR.1SA0x?O  
fileSplitterFetch.splitterStop(); MUhC6s\F  
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} o@>{kzCx  
} / *RDy!m  
//负责部分文件的抓取 7g[m,48{  
**FileSplitterFetch.java orVsMT[A  
*/ b'Pq[ )  
package NetFox; ?&I gD.  
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import java.io.*; #+N\u*-S  
import java.net.*; bE#=\kf|  
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public class FileSplitterFetch extends Thread { *%l&'+   
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String sURL; //File URL `zGK
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long nStartPos; //File Snippet Start Position Tf7$PSupP  
long nEndPos; //File Snippet End Position gcqcY  
int nThreadID; //Thread's ID r(h&=&T6  
boolean bDownOver = false; //Downing is over BIEc4k5(  
boolean bStop = false; //Stop identical d)1)/Emyj  
FileAccessI fileAccessI = null; //File Access interface jb~a z  
7?-eR-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (JH LWAH  
{ 5LbU'5  
this.sURL = sURL; ]wh8m1  
this.nStartPos = nStart; I<e[/#5P\`  
this.nEndPos = nEnd; /d=i0E3  
nThreadID = id; nF~</>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,Xs%Cg_Ig  
} vo)
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public void run() F`SOF O  
{ <h^'x7PkW5  
while(nStartPos < nEndPos && !bStop) VgtWT`F.I  
{ rUEoz|e4a  
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try{ S8*VjG?T\  
URL url = new URL(sURL); lTJ1]7)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o90SXa&l/  
httpConnection.setRequestProperty("User-Agent","NetFox"); ePdM9%  
String sProperty = "bytes="+nStartPos+"-"; F@Y)yi?z  
httpConnection.setRequestProperty("RANGE",sProperty); e
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Utility.log(sProperty); "~Twx]Z  
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InputStream input = httpConnection.getInputStream(); x|i"x+o  
//logResponseHead(httpConnection); Qmle0ae  
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byte[] b = new byte[1024]; =]&?(Gq  
int nRead; 'c<vj jIg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /%C6e )7BL  
{ 8:;_MBt  
nStartPos += fileAccessI.write(b,0,nRead); bq[j4xH0X  
//if(nThreadID == 1) *(Y
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yr@_X  
} 2ME"=!&5  
0JQy-hpF  
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Utility.log("Thread " + nThreadID + " is over!"); EbSH)aR  
bDownOver = true; }c1Vu  
//nPos = fileAccessI.write (b,0,nRead); @GqPU,RO  
} 1{4d)z UB  
catch(Exception e){e.printStackTrace ();} [Av#Z)R  
} fN~kdm.  
} 0h-holUf}~  
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^0"NcOzzxl  
//打印回应的头信息 zqfv|3-!}  
public void logResponseHead(HttpURLConnection con) DrLNY"Zq  
{ []:;8fY  
for(int i=1;;i++) $T{,3;kt  
{ 
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String header=con.getHeaderFieldKey(i); e`k6YO  
if(header!=null) fL.;-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =MDir$1Z  
Utility.log(header+" : "+con.getHeaderField(header)); zIt-mU  
else U^vQr%ha  
break; #&0)kr66  
} ZOc1 vj  
} fiOc;d8  
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7)$U>|=  
public void splitterStop() ";}Lf1M9  
{ Vd3'dq8/?  
bStop = true; ^6[KzE#*  
} 8v@6 &ras@  
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} IGv_s+O-*  
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/* v1<gNb)`  
**FileAccess.java `bu3S}m7  
*//文件访问(定位，写) Af1izS3  
package NetFox; Cnd70tbD )  
import java.io.*; 
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public class FileAccessI implements Serializable{ 21D4O,yCe  
}HtP8F8!x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w{k8Y?  
RandomAccessFile oSavedFile; 5,`U3na,  
long nPos; EJ{Z0R{{  
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public FileAccessI() throws IOException 5w"f.d'  
{ ]\5@N7h  
this("",0); )V~Fl$A  
} .z&V!2zp  
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public FileAccessI(String sName,long nPos) throws IOException q9o =,[  
{ {6Lkh  
oSavedFile = new RandomAccessFile(sName,"rw"); [:sPZ{  
this.nPos = nPos; %y.9S=,v,  
oSavedFile.seek(nPos); ^;+lsEW  
} !Sr^4R+Z  
" ] 0ER  
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public synchronized int write(byte[] b,int nStart,int nLen) 2uFaAAT  
{ @QI]P{  
int n = -1; k1Zu&4C\  
try{ hnZI{2XzBE  
oSavedFile.write(b,nStart,nLen); c'OJodp
a  
n = nLen; sj a;N
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} J7$1+|"  
catch(IOException e) N[X%tf\L]F  
{ rg+28tlDn  
e.printStackTrace (); S!.aBAW  
} #n%?}  
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return n; 0h!2--Aur  
} BF8n: }9U  
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} }u cqzdk#2  
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/* fHvQ9*T  
**SiteInfoBean.java f/Km$#xOr  
*/ #b\&Md|;  
package NetFox; xP*9UXZ4
P  
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public class SiteInfoBean { &:=   
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private String sSiteURL; //Site's URL C.L5\"%  
private String sFilePath; //Saved File's Path ,{ CgOz+Ul  
private String sFileName; //Saved File's Name VOwt2&mZ  
private int nSplitter; //Count of Splited Downloading File ?2[=llS4  
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public SiteInfoBean() l2GMVAca  
{//nSplitter的缺省值为5 ]Vhhx`0  
//default value of nSplitter is 5 +JZ<9,4  
this("","","",5); -cyJjLL*  
} ;d G.oUk=  
$>v^%E;Y4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j>gO]*BX~  
{ T'i9_V{  
sSiteURL= sURL; toPA@V  
sFilePath = sPath; hor ok:{  
sFileName = sName; Djx9TBZ5  
this.nSplitter = nSpiltter; OP |{R7uC  
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} =sRd5aMs  
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. hHt+  
public String getSSiteURL() |[D~7|?  
{  ;Fcdjy  
return sSiteURL; Dn$zwksSs  
} 1p
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\sHM[nF0  
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public void setSSiteURL(String value) .Y'kDuUu  
{ B;4hI?  
sSiteURL = value; -qfd)A6]  
} #@BM1BpQ  
I5'^tBf[{  
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public String getSFilePath() 9Q=g]int u  
{ OTtSMO  
return sFilePath; H(Mlf  
} iJ42` 51  
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/r@P\_  
public void setSFilePath(String value) \|R`wFn^P  
{ QC~B8]  
sFilePath = value; SynxMUlA  
} l1jS2O(  
X X{:$f+  
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public String getSFileName() v0X5`VV  
{ '\1%%F7  
return sFileName; Q9K Gf;  
} R.A}tV=j#  
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public void setSFileName(String value) ]gTaTY  
{ )_+"  
sFileName = value; _kH#{4`Hw  
} %P_\7YBC>  
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public int getNSplitter() QC4_\V
>[  
{ tt|U,o  
return nSplitter; AEPgQ9#E  
} |Y(].G,  
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public void setNSplitter(int nCount) ksDG8^9>]  
{ "$0f.FO:i  
nSplitter = nCount; W$gSpZ_7  
} K/Q;]+D  
} &>I8^i  
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/* H=X>o.iVqi  
**Utility.java zF)_t S  
*/ m>:%[vm  
package NetFox; U@& <5'  
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public class Utility { 54uTu2  
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public Utility() 68I4MZK>4  
{ EXa6"D  
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} uO[4 WZ  
W\} VZY  
//线程睡眠 A*E4
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public static void sleep(int nSecond) ,z%F="@b9  
{ Crpkq/M  
try{ ::TUSz2/2  
Thread.sleep(nSecond); bL0+v@(r  
} DMf^>{[  
catch(Exception e) d_5h6Cz4  
{ ~d{E>J77j  
e.printStackTrace (); !\aw
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} t"0~2R6i  
} a$aI%  
SI;G|uO;/  
//日志 uT-WQ/id  
public static void log(String sMsg) }a<MVG:>SF  
{ ,nHz~Xi1t  
System.err.println(sMsg); +nJ}+|@
K  
} G)<k5U4  
\re.KB#R  
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public static void log(int sMsg) B.Xm*adBT  
{ ,{oP`4\Lm  
System.err.println(sMsg); W_sDF; JP  
} "X]ufZ7  
} //LXbP3/  
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/* { @-Q1  
**TestMethod.java ?: meix  
*/ (4g;-*N  
package NetFox; ]/$tt@h  
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public class TestMethod { }kOhwT8sI  
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public TestMethod() (nE$};c<b2  
{ ///xx/weblogic60b2_win.exe wfZ'T#1  
try{ Ak_;GvC!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6]rrj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zP9 HYS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /(}V!0\?  
fileFetch.start(); D!Gm9Pa}  
} E'r* g{,  
catch(Exception e){e.printStackTrace ();} W6_3f-4g  
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} (c}0Sg  
{M%"z,GL7J  
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public static void main(String[] args) "M:arP5f  
{  (K?[gI  
new TestMethod(); hh8UKEM
-  
} 17 j7j@s)  
} ]&r/
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