http断点续传简单实现（java)

/* ;Y5"[C9|  
**SiteFileFetch.java ER~m &JI  
*/ $=uyZTYF)}  
package NetFox; AmNmhcN  
import java.io.*; Adp:O"-H1o  
import java.net.*; #80DM  
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public class SiteFileFetch extends Thread { h~)oiT2v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6*u#^">,<  
long[] nStartPos; //开始位置 J;,6ydf8!  
long[] nEndPos; //结束位置 j38>,9u,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %wn|H>  
long nFileLength; //文件长度 [hSE^ m  
boolean bFirst = true; //是否第一次取文件 gVjI1{WTK  
boolean bStop = false; //停止标志 r\Nf309~  
File tmpFile; //文件下载的临时信息 xZZW*d_b  
DataOutputStream output; //输出到文件的输出流 rK)aR  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FZ'|z8Dm  
public SiteFileFetch(SiteInfoBean bean) throws IOException RL7OFfMe  
{ =Bo(*%  
siteInfoBean = bean; m,NUNd#)\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Jy?s'tc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YzJ\< tkp  
if(tmpFile.exists ()) n=!]!'h\:  
{ NPy{ =#k4  
bFirst = false; 1^ZQXUzl%i  
read_nPos(); $BKGPGmh  
} 3on]#/"1b  
else #ak2[UOT  
{ jH#Tt;  
nStartPos = new long[bean.getNSplitter()]; HTiqErD2_  
nEndPos = new long[bean.getNSplitter()]; t<s:ut)Q!  
} gBfYm  
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} g((glr)6M  
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public void run() x LR 2H>B}  
{ \o3)\ e]o  
//获得文件长度  *X- 6]C  
//分割文件 pwAawm  
//实例FileSplitterFetch jq#gFt*  
//启动FileSplitterFetch线程 `_Iy8rv:P  
//等待子线程返回 9[K".VeT]  
try{ cr
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if(bFirst) A8 V7\  
{ )HbsUm#  
nFileLength = getFileSize(); 6Yhd
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if(nFileLength == -1) Si#I^aF`%  
{ )jkX&7x  
System.err.println("File Length is not known!"); sUA==k  
} A*#.7Np!"  
else if(nFileLength == -2) "`]G>,r_  
{ H0<(j(JK  
System.err.println("File is not access!"); wz^Q,Od  
} 6d/;GyG  
else hbm%{*d  
{ a9S0glbwf  
for(int i=0;i<nStartPos.length;i++) \; ! oG  
{ xL8r'gV@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vf6_oX<Os  
} }z{2~ 0,  
for(int i=0;i<nEndPos.length-1;i++) /Y$UJt  
{ qW*JB4`?a  
nEndPos = nStartPos[i+1]; y'\BpP  
} j\l9|vpp  
nEndPos[nEndPos.length-1] = nFileLength; a+A^njk  
} 9gP-//L@  
} gB/4ro8  
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sb"z=4  
//启动子线程 lbM)U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z}I=:  
for(int i=0;i<nStartPos.length;i++) m(MPVY<X  
{ H",w$$eF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2ghTAsUx9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~2 L{m[s|  
nStartPos,nEndPos,i); ]7<}EG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~aKM+KmtPH  
fileSplitterFetch.start(); "|P8L| @*  
} \Tf[% Kt x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6*yt^[W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v4M1uJ8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ay?KE{Qs '  
nEndPos = " + nFileLength); hP1}Do  
// fileSplitterFetch[nPos.length-1].start(); ;',hwo_LBf  
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//等待子线程结束 oU/CXz?H  
//int count = 0; }:JE*D|  
//是否结束while循环
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boolean breakWhile = false; -+vA9,pI  
:[icd2JCw]  
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while(!bStop) ;. jnRPo";  
{ VI83 3  
write_nPos(); zadn`B#2  
Utility.sleep(500); dnRS$$9#  
breakWhile = true; K)NB{8 _  
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for(int i=0;i<nStartPos.length;i++) 8?p40x$m%  
{ P-B3<~*i!  
if(!fileSplitterFetch.bDownOver) yb 7  
{ pPI'0x  
breakWhile = false; 3&H#LGoV$  
break; S"t6 *fWr  
} TVaD',5_V%  
} rHS;wT  
if(breakWhile) y2"PKBK\_  
break; $raxf80A  
;ZnSWIF2  
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//count++; H{XbKLU  
//if(count>4) z^@.b  
// siteStop(); =m<; Jx5  
} h8R3N?S3#  
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System.err.println("文件下载结束！"); }b$?t7Q)  
} q?R)9E$h  
catch(Exception e){e.printStackTrace ();} #Az#dt]H  
} kzMul<>sl  
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+C
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//获得文件长度 oJ r&9.S  
public long getFileSize() ;3 N0)  
{ ,'FH[2  
int nFileLength = -1; +I>u${sVx*  
try{ $P=B66t ^  
URL url = new URL(siteInfoBean.getSSiteURL()); ;m/h?Y~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X@ zw;Se  
httpConnection.setRequestProperty("User-Agent","NetFox"); hDO\Q7  
 O=,[u?  
z
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int responseCode=httpConnection.getResponseCode(); 2kP0//  
if(responseCode>=400) DC&3=Nd  
{ h=:*cqp4  
processErrorCode(responseCode); {ylY"FA  
return -2; //-2 represent access is error +"sjkdum1  
} K-_XdJ\  
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String sHeader; ^M:Y$9r_s  
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{;z{U;j  
for(int i=1;;i++) UN FQ`L  
{ i6S5 4&^!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w^AY= Fc  
//Utility.log(in.readLine()); iMT[sb  
sHeader=httpConnection.getHeaderFieldKey(i); >MTrq%.  
if(sHeader!=null) =:w]EpH"  
{ 3/aK#TjK  
if(sHeader.equals("Content-Length")) _1c0pQ^}3  
{ eD(;Wn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &oz^dlw  
break; :V9%R~h/  
} Q)/V>QW  
} _/Sq
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else >/]` f8^  
break; #Nv^F  
} H%nA"-  
} N$!aP/b  
catch(IOException e){e.printStackTrace ();} y;\m1o2  
catch(Exception e){e.printStackTrace ();} "jUM}@q5  
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Utility.log(nFileLength); R&-Vm3mc3  
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return nFileLength; \&6^c=2=  
} iBM;$0Y  
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//保存下载信息（文件指针位置） h7P<3m}  
private void write_nPos() <dD)>Y.  
{ +55+%oGl  
try{ ee}HQ.}Ja  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )bgaqca_{  
output.writeInt(nStartPos.length); fi,h`mdT?  
for(int i=0;i<nStartPos.length;i++) {vhP'!a6W  
{ t@;r~Sb  
// output.writeLong(nPos); NT0im%  
output.writeLong(fileSplitterFetch.nStartPos); 6CV9ewr  
output.writeLong(fileSplitterFetch.nEndPos); joRrsxFU  
} :~{Nf-y0`1  
output.close(); m-HL7&iG$  
} rRQKW_9mB  
catch(IOException e){e.printStackTrace ();} (a9>gLI0  
catch(Exception e){e.printStackTrace ();} xU!eT'Y  
} FK+`K<  
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//读取保存的下载信息（文件指针位置） ls@j8bVv^  
private void read_nPos() >Y6iLQ$X  
{ Ncr*F^J4  
try{ 1!
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;
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int nCount = input.readInt(); v,d bto0  
nStartPos = new long[nCount]; :Ldx^UO  
nEndPos = new long[nCount]; t)l  
for(int i=0;i<nStartPos.length;i++) (3Dz'X  
{ m#,AD,s  
nStartPos = input.readLong(); VsQ~Y,7  
nEndPos = input.readLong(); p9-s'F|@i  
} KK';ho,W  
input.close(); 63fgl+  
} .Y5o&at6s  
catch(IOException e){e.printStackTrace ();} fc<~R  
catch(Exception e){e.printStackTrace ();} skP'- ^F~  
} i@L_[d^|j`  
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private void processErrorCode(int nErrorCode) ?J,K[.z  
{ Pk{%2\%&2  
System.err.println("Error Code : " + nErrorCode); REGk2t.L  
} %PlA9@:IZ  
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FaLc*CU  
//停止文件下载 Ih<.2  
public void siteStop() yi;pn Z  
{ 7V2xg h!W  
bStop = true; jdX*  
for(int i=0;i<nStartPos.length;i++) IAi|4,y_L  
fileSplitterFetch.splitterStop(); )m$M
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} tF:AqR:(~  
} lSG]{  
//负责部分文件的抓取 6E{(_i  
**FileSplitterFetch.java rcz9\@M  
*/ X$*]$Ge>  
package NetFox; _>E=.$  
ML.|\:r*  
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import java.io.*; oTg 'N  
import java.net.*; 8 .t3`FGH  
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public class FileSplitterFetch extends Thread { M.67[Qj~"u  
j@R"AP}  
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String sURL; //File URL xEg@Y"NQ  
long nStartPos; //File Snippet Start Position cHC4Y&&uZ  
long nEndPos; //File Snippet End Position cAq5vAqmg  
int nThreadID; //Thread's ID bT^(D^  
boolean bDownOver = false; //Downing is over p"0Dl9  
boolean bStop = false; //Stop identical Zi}jf25  
FileAccessI fileAccessI = null; //File Access interface \ #N))gAQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :{9HsF"h0  
{ L=dQ,yA  
this.sURL = sURL; P1^O0)  
this.nStartPos = nStart; owx0J,,G  
this.nEndPos = nEnd; X>%li$9J.  
nThreadID = id; gwbV$[.X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =fJ
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} C]&/k_k  
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public void run() ZK h4:D  
{ qJE_4/<^!  
while(nStartPos < nEndPos && !bStop) yL
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{ "m`}J*s"  
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try{ 6xFchdMG{m  
URL url = new URL(sURL); $>T(31)c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v'm-A d+4t  
httpConnection.setRequestProperty("User-Agent","NetFox"); fw5+eTQ^  
String sProperty = "bytes="+nStartPos+"-"; %Fx^"  
httpConnection.setRequestProperty("RANGE",sProperty); 5uV_Pkb?8  
Utility.log(sProperty); gvr&7=p  
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InputStream input = httpConnection.getInputStream(); i-9W8A  
//logResponseHead(httpConnection); J50n E~  
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byte[] b = new byte[1024]; _St":9'uU  
int nRead; 2O- 4x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =!)x`1j!S  
{ uw/N`u  
nStartPos += fileAccessI.write(b,0,nRead); jz
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//if(nThreadID == 1) y\,,hs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _2{2Xb  
} {pdPp|YDZ-  
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_ gGA/   
Utility.log("Thread " + nThreadID + " is over!"); -q8l"i>h=  
bDownOver = true; G9Noch9 g  
//nPos = fileAccessI.write (b,0,nRead); W>qu~ak?x  
} W.%p{wB|  
catch(Exception e){e.printStackTrace ();} X"9N<)C  
} |bhv7(_  
} +d?|R5{3  
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//打印回应的头信息 Kz
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public void logResponseHead(HttpURLConnection con) Yf
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{ "G,,:H9v  
for(int i=1;;i++) `$XB_o%@  
{ dkY
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String header=con.getHeaderFieldKey(i); YQyI{  
if(header!=null) !D?(}nag  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @e
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Utility.log(header+" : "+con.getHeaderField(header)); y^[t3XA6Q  
else aXzb]">  
break; =qbN?a/?2  
} mkfDDl2 GP  
} )Gk?x$pY@  
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public void splitterStop() LwTdmR  
{ ^)GaVL^"5  
bStop = true; hS*&p0YV~M  
} o4OB xHKy  
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} ZJ~0o2xZ'  
6!
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/* Rkp +}@Y_  
**FileAccess.java Z:Vde^Ih  
*//文件访问(定位，写) dA E85  
package NetFox; _sZ&=-FR  
import java.io.*; Nr+~3:3  
~kj96w4eAR  
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public class FileAccessI implements Serializable{ [8q`~S%-]  
GU9G5S.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D(TG)X?  
RandomAccessFile oSavedFile; J7C?
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long nPos; nP<u.{q L  
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public FileAccessI() throws IOException tN_=&|{WE4  
{ b:r8r}49  
this("",0); lkly2|wA  
} rNKeY48\  
n%G[Y^^,  
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public FileAccessI(String sName,long nPos) throws IOException a(*"r:/lD  
{ m/jyc# L:u  
oSavedFile = new RandomAccessFile(sName,"rw"); 6Vncr}  
this.nPos = nPos; 7'65+c[&  
oSavedFile.seek(nPos); :-<30LS$  
} #_`p 0wY  
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public synchronized int write(byte[] b,int nStart,int nLen) nd,\<}uP9  
{ \x:U`T  
int n = -1; K'e,9P{  
try{ N6p
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oSavedFile.write(b,nStart,nLen); ZMr[:,Jp  
n = nLen; {T,}]oX  
} =S6bP<q  
catch(IOException e) Y~Vc|zM^(  
{ nk_X_y  
e.printStackTrace (); OwPH
p&{ Y  
} c`hENPhW  
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return n; `8#xO{B1  
} z_'!?
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} k%\y,b*  
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/* ePl+ M  
**SiteInfoBean.java e-UWbn'~  
*/ ?azLaAG  
package NetFox; 0H.bRk/P+  
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public class SiteInfoBean { n[qnrk*3 %  
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private String sSiteURL; //Site's URL 4 #KC\C  
private String sFilePath; //Saved File's Path \K}KnJ  
private String sFileName; //Saved File's Name (fr=[m$`  
private int nSplitter; //Count of Splited Downloading File _D@QsQ_Z  
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public SiteInfoBean() PY4a3dp U  
{//nSplitter的缺省值为5 Z,\(bW qF  
//default value of nSplitter is 5 pFiE2V_aS  
this("","","",5); UHTxNK@}  
} $G}k'[4C  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7@y}J5,  
{ @"
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sSiteURL= sURL; [; $:Lr  
sFilePath = sPath; y?3u6q++  
sFileName = sName; xO%yjG=  
this.nSplitter = nSpiltter; pNuU{:9 B0  
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} =>Z4vWX*  
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public String getSSiteURL() qPUACuF'  
{ X MF
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return sSiteURL; < 0S\P=\  
} GMLx$?=j  
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public void setSSiteURL(String value)  n[v`F  
{ 8Jp?@qt=$  
sSiteURL = value; 7~P!Z=m^^f  
} l+`CgYo  
6"rS?>W/mO  
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public String getSFilePath() [5M!'  
{ _x`:Ne?  
return sFilePath; ,g|ht%"  
} ]^a{?2ei  
6/(Z*L"~6k  
#a8i($k{e  
public void setSFilePath(String value) ]i `~J  
{ $m+Pl[s  
sFilePath = value; P;&U3i  
} A9[
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public String getSFileName() z^%`sUgP  
{ $"=0{H.?  
return sFileName; [{ A5BE -  
} IZ
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n
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public void setSFileName(String value) 1py>[II@  
{ g%4=T~  
sFileName = value; :{Iv ]d  
} ;b, bHL  
o
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public int getNSplitter() J'lqHf$T  
{ gkx<<)y l  
return nSplitter; AAc2u^spx  
} ZQ#AEVI,  
E `%*lGu_  
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public void setNSplitter(int nCount) +j6^g*  
{ j2%#xZ{
33  
nSplitter = nCount; ;AarpUw'  
} B :1r;8{j  
}  0LU

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/* [>kzQYT[  
**Utility.java '[[*(4a3  
*/ ')E4N+h/  
package NetFox; ~NO'8Mr  
>vQKCc|93  
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public class Utility { <d3N2  
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v;R+{K87  
public Utility() fu`|@
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{ ZL- ` 3x  
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DYL\=ya1  
} '\B!1B>T  
0kld77tn 2  
//线程睡眠 lO^YAOY  
public static void sleep(int nSecond) }F)eA1  
{ ltG|#(  
try{ -gLU>I7wV  
Thread.sleep(nSecond); SV_b(wP9  
} u]QG^1.qYe  
catch(Exception e) #N|A@B5x  
{ 4
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e.printStackTrace (); TInp6w+u  
} Zk 9i}H  
} l#%G~c8x  
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//日志 ^o6&|q  
public static void log(String sMsg) r
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{ ;"DI)hdz  
System.err.println(sMsg); Ng<oz*>U  
} u-#J!Z<T8  
l(
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^>!~%Vv7!  
public static void log(int sMsg) {,C
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{ bmGtYv  
System.err.println(sMsg); I r;Z+}4>Y  
} :l?/]K  
} S?LUSb  
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g|V0[Hnq6  
/* A**PGy.Ni  
**TestMethod.java S.A|(?x  
*/ =OF]xpI'&a  
package NetFox; >qjV(_?F-  
#`{L_n
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public class TestMethod { .</.(7  
QF`o%mI  
(J/!9NS:  
public TestMethod() p*S;4+>#  
{ ///xx/weblogic60b2_win.exe Gf1O7L1rX  
try{ xSoXf0zq:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8ORr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,}_uk]AQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h|t\rV^  
fileFetch.start(); Kf-rthO  
} 1*J#:|({(  
catch(Exception e){e.printStackTrace ();} U/I+A|S[  
0vm}[a4+i;  
$y&1.caMa  
} @s/0 .7  
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public static void main(String[] args) "sU ~|  
{ Ffp<|2T2_  
new TestMethod(); z("Fy  
} <E.$4/T  
} ``4lomz>  
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