http断点续传简单实现（java)

/* W,'30:#Fr7  
**SiteFileFetch.java v.Wkz9 w}  
*/ seO7/h_a  
package NetFox; KLi&TmIB  
import java.io.*; R+Q..9P  
import java.net.*; >.^/Z/[.L  
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public class SiteFileFetch extends Thread { HAJK%zLc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean T;jy2|mLo  
long[] nStartPos; //开始位置 *V}T}nK7  
long[] nEndPos; //结束位置 U'8+YAgc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4 0as7.q  
long nFileLength; //文件长度 {T EF#iF  
boolean bFirst = true; //是否第一次取文件 i!5zHn  
boolean bStop = false; //停止标志 CsfGjqpf  
File tmpFile; //文件下载的临时信息 8bT]NvCA  
DataOutputStream output; //输出到文件的输出流 Hxe!68{aR  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =y)e&bj  
public SiteFileFetch(SiteInfoBean bean) throws IOException ? I7}4i7  
{ >S\D+1PV  
siteInfoBean = bean; fX"cQ&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LDilrG)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h8#14?  
if(tmpFile.exists ()) iK&s_}i:  
{ "SGq$3D  
bFirst = false; A#/O~-O^  
read_nPos(); );-?~   
} RlJt+lnV  
else ?J[m)Uo/K  
{ !>gi9z,  
nStartPos = new long[bean.getNSplitter()]; J${'?!N  
nEndPos = new long[bean.getNSplitter()]; };{V]f 0  
} c8'a<<sj  
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} OEMYS I%  
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public void run() @ Gxnrh6  
{ PL*Mz(&bf  
//获得文件长度 tCZ3n  
//分割文件 E8$k}I  
//实例FileSplitterFetch j0^%1  
//启动FileSplitterFetch线程 [1Cs  
//等待子线程返回 ry^FJyjW  
try{ .;),e#  
if(bFirst) ']]Czze  
{ r57CyO  
nFileLength = getFileSize(); k'H+l]=  
if(nFileLength == -1) `v;9!ReZV  
{ ,ddoI
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System.err.println("File Length is not known!"); zvJQ@i"Z  
} Yi?X|
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else if(nFileLength == -2) %ae|4u#b  
{ ddR*&.Y!a  
System.err.println("File is not access!"); M1UabqQ  
} T >BlnA  
else ."HDUo2D7  
{ nd~cpHQR^  
for(int i=0;i<nStartPos.length;i++) ^ud-N;]MKs  
{ LmCr[9/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,0j7qn@tm  
} =
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for(int i=0;i<nEndPos.length-1;i++) #kho[`9  
{ o|r8x_!+  
nEndPos = nStartPos[i+1]; X*4iNyIs_  
} z`)i"O]-K_  
nEndPos[nEndPos.length-1] = nFileLength; : T` Ni  
} Kyn[4Bu!?  
} F@4TD]E0^  
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//启动子线程 Tf0"9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H rMH  
for(int i=0;i<nStartPos.length;i++) Gcu[G]D  
{ Ii*tux!S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1W@ C]n4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "#<P--E9  
nStartPos,nEndPos,i); #RfNk;kaA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cJp:0'd  
fileSplitterFetch.start(); 2kG(\+\  
} I%
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), no~Yet+<"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6A$ Y]u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ->H4!FS  
nEndPos = " + nFileLength); /RWQ+Zf-Y]  
// fileSplitterFetch[nPos.length-1].start(); "`va_Mk  
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//等待子线程结束 0ZRIi70u  
//int count = 0; *!mT#Vm^  
//是否结束while循环 QB3vp4pBg@  
boolean breakWhile = false; 1$+-?:i C  
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while(!bStop) QYS 1.k  
{ E2hy%y9Tp  
write_nPos(); NA=I7I@  
Utility.sleep(500); !PAuMj)P  
breakWhile = true; d3,%Z &  
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for(int i=0;i<nStartPos.length;i++) D]P_tJI  
{ pUp&eH  
if(!fileSplitterFetch.bDownOver) T6Oah:50EM  
{ B\<;e  
breakWhile = false; #L3heb&9  
break; obRYU
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} t@_MWF  
} W##~gqZ/  
if(breakWhile) cN{(XmX5n  
break; )(4.7>  
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//count++; XA1gV>SJ  
//if(count>4) V"A*k^}  
// siteStop(); tAi ~i;?  
} F]fBFDk  
.m;5s45O{  
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System.err.println("文件下载结束！"); g`n5-D@3  
} < 2mbR  
catch(Exception e){e.printStackTrace ();} K[j~htC{I"  
} VKZZTFmV2)  
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//获得文件长度 (4GDh%  
public long getFileSize() KscugX*x  
{ MS>QU@z7c  
int nFileLength = -1; n7>L&?N#y#  
try{ U8||)+  
URL url = new URL(siteInfoBean.getSSiteURL()); VGe OoS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $\9M6k'  
httpConnection.setRequestProperty("User-Agent","NetFox"); [yyL2=7  
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int responseCode=httpConnection.getResponseCode(); XCP/e p  
if(responseCode>=400) <3SO1@
?  
{ Yg~$1b@  
processErrorCode(responseCode); A.8[FkiNmD  
return -2; //-2 represent access is error 8AGP*"gI  
} 4?u<i=i  
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String sHeader; rBLcj;,
 
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for(int i=1;;i++) Y}n$s/O:u8  
{ DwNEqHi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S.! n35  
//Utility.log(in.readLine()); # fe%E.  
sHeader=httpConnection.getHeaderFieldKey(i); ^U8^P]{R|  
if(sHeader!=null) Mhwuh`v%  
{ 5ltrr(MeD  
if(sHeader.equals("Content-Length")) wk@S+Q  
{ 0Mo?9??  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }2!=1|}  
break; Y9w^F_relL  
} |ctcY*+  
} zF7*T?3b"  
else @dHQ}Ni  
break; ]Jum(1Bo  
} kc:>[{9  
} [" PRxl  
catch(IOException e){e.printStackTrace ();} DKG99biJN  
catch(Exception e){e.printStackTrace ();} b"PRa|]  
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Utility.log(nFileLength); QIWfGVc-  
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return nFileLength; d95 $w8>  
} NGs@z^&V  
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//保存下载信息（文件指针位置） u|T
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private void write_nPos() bMvHAtp  
{ 0)0,&@])7  
try{ I%b}qC"5M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <fm<UO,%  
output.writeInt(nStartPos.length); D\LXjEme.  
for(int i=0;i<nStartPos.length;i++) P:QSr8K  
{ ^!j,d_)b!  
// output.writeLong(nPos); ui!MQk+D9  
output.writeLong(fileSplitterFetch.nStartPos); n]<>$  
output.writeLong(fileSplitterFetch.nEndPos); Xf/qUa
o  
} 1$toowb"Zy  
output.close(); :H8`z8=0f{  
} 2t3DQ  
catch(IOException e){e.printStackTrace ();} (kFg2kG  
catch(Exception e){e.printStackTrace ();} C_rA'Hy  
} z:JQ3D7/we  
J;#7dRW{  
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//读取保存的下载信息（文件指针位置） ^)%TQ.  
private void read_nPos() o'*7I|7a  
{ g?1! /+  
try{ c>)_I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _!:*&{  
int nCount = input.readInt(); .ZVADVg\  
nStartPos = new long[nCount]; SMMvRF`7  
nEndPos = new long[nCount]; )ePQN~#K}  
for(int i=0;i<nStartPos.length;i++) lG/h[  
{ 6b7SA,  
nStartPos = input.readLong(); KwxO%/-}S  
nEndPos = input.readLong(); AD0pmD  
} (d?sFwOt\  
input.close(); |<Rf^"T  
} =*'K'e>P3  
catch(IOException e){e.printStackTrace ();} zv>7;E
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catch(Exception e){e.printStackTrace ();} Pgo^$xn'6  
} V 3yt{3Or  
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private void processErrorCode(int nErrorCode) EpdSsfDP  
{ <UE-9g5?G  
System.err.println("Error Code : " + nErrorCode); 3OvQ,^[J4  
} 2(s-8E:  
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//停止文件下载
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public void siteStop()
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{ grbUR)f<?-  
bStop = true; ?_BK(kL_  
for(int i=0;i<nStartPos.length;i++) ]`H8r y2  
fileSplitterFetch.splitterStop(); [7sy}UH  
V^D!\)#  
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} SMIr@*R  
} u0?,CQPL  
//负责部分文件的抓取 12y+g5b  
**FileSplitterFetch.java :J~sz)n4  
*/ wu`P=-
 
package NetFox; D\9
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import java.io.*; jFPD SR5  
import java.net.*; pdEUDuX  
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public class FileSplitterFetch extends Thread { IWs)n1D*]  
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String sURL; //File URL Puodsd  
long nStartPos; //File Snippet Start Position @p$$BUb  
long nEndPos; //File Snippet End Position v#`7,::  
int nThreadID; //Thread's ID n04lTME  
boolean bDownOver = false; //Downing is over A.>L>uR  
boolean bStop = false; //Stop identical fXfO9{E  
FileAccessI fileAccessI = null; //File Access interface l6z}D;4  
{wy#HYhv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c@<vFoq  
{ _X"G(  
this.sURL = sURL; Y2
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this.nStartPos = nStart; 04}" n  
this.nEndPos = nEnd; )D>= \Me  
nThreadID = id; *wNO3tP't  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Di>
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} /+g)J0
u  
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public void run() ~3r}6,%  
{ au~}s |#  
while(nStartPos < nEndPos && !bStop) ~uRL+<.c  
{ 9f7T.}HM  
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try{ pj/w9j G6  
URL url = new URL(sURL); ML-?#jNa<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SU80i`  
httpConnection.setRequestProperty("User-Agent","NetFox"); dWDM{t\}\  
String sProperty = "bytes="+nStartPos+"-"; \Zbi`;m?  
httpConnection.setRequestProperty("RANGE",sProperty); {ZR>`'^:  
Utility.log(sProperty); hsEQ6  
R\^XF8n6/  
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InputStream input = httpConnection.getInputStream(); ,,o5hD0V9  
//logResponseHead(httpConnection); MbJ|6
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byte[] b = new byte[1024]; wr{ [4$O  
int nRead; K! e5
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ubf@"B  
{ '3eL^Aq  
nStartPos += fileAccessI.write(b,0,nRead); Z&[_8Y5j  
//if(nThreadID == 1) ;fl3'.S[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2uy<wJE>  
} ocDAg<wo  
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| l
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Utility.log("Thread " + nThreadID + " is over!"); #[ZNiaWT  
bDownOver = true; NpN-''B\  
//nPos = fileAccessI.write (b,0,nRead); >2[nTfS  
} Vb$
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catch(Exception e){e.printStackTrace ();} A[6D40o  
} R
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} =&YhA}l\O  
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//打印回应的头信息 m\xlSNW'q  
public void logResponseHead(HttpURLConnection con) s6+`cC4  
{ ro`2IE>  
for(int i=1;;i++) -lDAxp6p  
{ uqFYa bU  
String header=con.getHeaderFieldKey(i); bz4TbGg]  
if(header!=null) TeXt'G=M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /lqVMlz\77  
Utility.log(header+" : "+con.getHeaderField(header)); n,vs(ZL:  
else
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break; uFl19  
} b<1+q{0r  
} IyJHKDFk  
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)ZqY`by!  
public void splitterStop() gtVnn]Jh  
{ 6tKCY(#oO+  
bStop = true; 8{ooLdpX7  
} 6(as.U>K  
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E Zh.*u@^r  
} =/zb$d cz  
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/* 0<'Q;'2* L  
**FileAccess.java .{ +Obi  
*//文件访问(定位，写) ~+OAAkJ9  
package NetFox; DLBHZ?+!  
import java.io.*; B;=-h(E}vJ  
zC<k4[.  
bDq[j8IT6  
public class FileAccessI implements Serializable{ j$ h>CZZ  
Oiz@tEp=_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6L}}3b h  
RandomAccessFile oSavedFile; _jCk)3KO  
long nPos; 'PK;Fg\  
|'ML )`c[  
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public FileAccessI() throws IOException >xB[k-C4  
{ @eOD+h'  
this("",0); ) u Sg;B4  
} q"C(`S.@  
i$CN{c*  
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public FileAccessI(String sName,long nPos) throws IOException gR\-%<42  
{ nEgD
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oSavedFile = new RandomAccessFile(sName,"rw"); %TUvH>;0  
this.nPos = nPos; M|DVFC  
oSavedFile.seek(nPos); ;FfDi*S7  
} l+HF+v$  
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public synchronized int write(byte[] b,int nStart,int nLen) &Ay[mZQ 7  
{ 97 eEqI$#  
int n = -1; 7xU6Ll+p  
try{ 43m@4Yb  
oSavedFile.write(b,nStart,nLen); 6#gS`X23Y  
n = nLen; d.Im{-S  
} aTLu7C\-e  
catch(IOException e) pEp`Z,p  
{ 2*)2c[/0F  
e.printStackTrace (); K~6,xZlDWM  
} rU!QXg]uD  
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|x#w8=VP-  
return n; ]/ffA|"U`  
} R!Lh~~@{(  
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} ]o+5$L,5b  
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/* 7H!/et?S,  
**SiteInfoBean.java PXrv2q[5?  
*/ /9@[gv A  
package NetFox; {i#z<ttu  
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public class SiteInfoBean { rZ#ZY  
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private String sSiteURL; //Site's URL )Gm,%[?2C  
private String sFilePath; //Saved File's Path $~
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private String sFileName; //Saved File's Name Qo$j'|lD  
private int nSplitter; //Count of Splited Downloading File  @^cR  
?DrA@;IB  
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public SiteInfoBean() Cno+rmsfT  
{//nSplitter的缺省值为5 1Wr,E#+C  
//default value of nSplitter is 5 Nbvs_>N  
this("","","",5); |w].*c}Z  
} HE|XDcYO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N(Sc!rX  
{ u8Ak2:   
sSiteURL= sURL; \`U=pZJ  
sFilePath = sPath; XT%\Ce!  
sFileName = sName; r\T'_wo  
this.nSplitter = nSpiltter; pt$\pQ  
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} hZ`<ID  
{|{;:_.>  
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public String getSSiteURL() l9t|@9  
{ Rl{e<>O\^  
return sSiteURL; B&L-Lc2  
} xQ,My  
5RsO^2V:  
/ DG t  
public void setSSiteURL(String value) L6x;<gj  
{ :Xi&H.k)p  
sSiteURL = value; g^: &D
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} VjLv{f<p  
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public String getSFilePath() SceK$  
{ b[KZJLZ)  
return sFilePath; ,n3e8qd  
} _J"fgxW  
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public void setSFilePath(String value) +3F%soum95  
{ =1Hn<Xay0  
sFilePath = value; p?2^JJpUb  
} R8-=N+hX  
?[<#>,W  
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public String getSFileName() SA?lDRF  
{ PH$C."Vv  
return sFileName; U'aJCM  
} 19b@QgfWpb  
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public void setSFileName(String value) jS ?#c+9  
{ ShesJj  
sFileName = value; 4<V}Aj8l  
} v`@M IOv  
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_#K?
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public int getNSplitter() hVIv->  
{ =m;,?("7t3  
return nSplitter; *#9?9SYSk  
} [Ob09#B%:5  
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=P%?{7  
public void setNSplitter(int nCount) ;pj,U!{%s\  
{ -}u1ZEND  
nSplitter = nCount; 0`V;;w8  
} xzHb+1+p  
} [/o BjiBA  
8]mRX~  
#/> a`Ur_  
/* wk#cJ`wG;  
**Utility.java lVCnu>8  
*/ :%_h'9Qq  
package NetFox; Vi`P &uPF  
KM"BHaSkF  
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public class Utility { :T{VCw:*  
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public Utility() ,BFw-A  
{ xX|f{)<  
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} _(-i46x}  
5"y)<VLJX  
//线程睡眠
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public static void sleep(int nSecond) K~4b
T=   
{ cJf&R^[T  
try{ )t((x  
Thread.sleep(nSecond); l9e=dV:pH  
} 9k\M<jA  
catch(Exception e) *cZ7?  
{ M@JW/~p'  
e.printStackTrace (); Tm$8\c4V:*  
} w
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} [dFe-2u ,$  
\l%##7DRp]  
//日志 x2TE[#><  
public static void log(String sMsg) |8tKN"QG  
{ =YIosmr  
System.err.println(sMsg); YYL3a=;`a  
} #&ei  
+IMt$}7[  
,`PYU[  
public static void log(int sMsg) ht#,v5oG>f  
{ EeHghq  
System.err.println(sMsg); @Ko#nDEq  
} -/ G#ls|?  
} `n@;%*6/  
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/* m#ig.z|A  
**TestMethod.java Vju/+  
*/ e
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package NetFox; #l
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public class TestMethod { F|cli <  
1:Ff#Eq,s  
5{WvV%  
public TestMethod() EI)2c.A  
{ ///xx/weblogic60b2_win.exe 2'@
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try{ nBLb1T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }u8g7Nj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @REMl~"D5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -p%cw0*Y]C  
fileFetch.start(); =v0w\( ?N  
} bN6i*)}  
catch(Exception e){e.printStackTrace ();} ~T/tk?:8Vi  
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} ;VEKrVD  
<2fy(9y  
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public static void main(String[] args) %%#bTyF  
{ <Ql2+ev6  
new TestMethod(); 24 .'+3  
} Jz*A!Li  
} cj^hwtx   
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