http断点续传简单实现（java)

/* 4^1{UlCop  
**SiteFileFetch.java FZ6.<wN  
*/ OziG|o
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package NetFox; MGCwT@P  
import java.io.*; l[.*X  
import java.net.*; ?<YtlqL  
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public class SiteFileFetch extends Thread { #r `hK)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a.v$+}+.[,  
long[] nStartPos; //开始位置 xAMj16ZF  
long[] nEndPos; //结束位置 wO@b=1j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @#c(4}^ <w  
long nFileLength; //文件长度 H'-Fv!l?  
boolean bFirst = true; //是否第一次取文件 =iC5um:  
boolean bStop = false; //停止标志 g2l|NI#c^  
File tmpFile; //文件下载的临时信息 pv+FP
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DataOutputStream output; //输出到文件的输出流 L01R.3Z+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .^N+'
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public SiteFileFetch(SiteInfoBean bean) throws IOException ,-ZAI b*  
{ wh l)^D  
siteInfoBean = bean; g><u(3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wb2N$Ew=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o^wj_#ai$  
if(tmpFile.exists ()) ez%RWck  
{ 'D#}ce)s#  
bFirst = false; c5>&~^~>Tx  
read_nPos(); _|D8~\y  
} 9aD6mp  
else +?zyFb]Km  
{ j9XY%4.  
nStartPos = new long[bean.getNSplitter()]; P1]ucu_y,  
nEndPos = new long[bean.getNSplitter()]; ~O?Gi 4^Yg  
} i)Vqvb0Q  
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} 1 h|cr_  
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public void run() PA5ET@mD  
{ *Af]?-|^{#  
//获得文件长度 SE)_
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//分割文件 Wznz  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 8kXbyKX[b  
//等待子线程返回 *E+2E^B  
try{ qEX2K^y'4"  
if(bFirst) @4^5C-  
{ Y}7'OM  
nFileLength = getFileSize(); Ij(S"P@  
if(nFileLength == -1) m<IPi <  
{ d%
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System.err.println("File Length is not known!"); #R4Mv(BG  
} A3*ti!X<6  
else if(nFileLength == -2) /p~"?9b[ i  
{ okoD26tK  
System.err.println("File is not access!"); J5)e 7  
} 8[Cp  
else eJ+;!0  
{ %P0dY:L~  
for(int i=0;i<nStartPos.length;i++) OYzt>hdH  
{ %eGxQDIXg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !;{@O`j?b  
} O*d&H;;  
for(int i=0;i<nEndPos.length-1;i++) *_`T*$  
{ hhlQ!WV2  
nEndPos = nStartPos[i+1]; pRx^O F(3  
} *yKsgH  
nEndPos[nEndPos.length-1] = nFileLength; >aW|W!.  
} %eT4Q~}5"  
} Dx$74~2e  
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z@>z.d4  
//启动子线程 M$ep.<Z1|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `~UCWK  
for(int i=0;i<nStartPos.length;i++) a3?Dtoy'  
{ N[^%|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %}%D8-d}G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J_}&Btb)e  
nStartPos,nEndPos,i); QtJe){(z+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); auAST;"Z8  
fileSplitterFetch.start(); Ictc '#y  
} )wP0U{7?v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _DMj)enH"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s#`%c({U|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0!9vGs  
nEndPos = " + nFileLength); 5 usfyY]z  
// fileSplitterFetch[nPos.length-1].start(); 4U<'3~RN  
a[\,K4l  
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//等待子线程结束 +'>N]|Z  
//int count = 0; 8V_ ]}W  
//是否结束while循环 ?*u)T%S  
boolean breakWhile = false; daWmF  
"sz LTC]*6  
Vm'ReH  
while(!bStop) L'6_~I  
{ z~4L=tA(  
write_nPos(); CWE jX-  
Utility.sleep(500); _S8]W !c  
breakWhile = true; -4,qAnuMx  
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for(int i=0;i<nStartPos.length;i++) bVt
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{ ^%M!!wlUH  
if(!fileSplitterFetch.bDownOver) ?XsL4HIx  
{ ZgtW  
breakWhile = false; \4K8*`$  
break; wC!(STu  
} cy)L%`(7  
} 9Vzk:zOT  
if(breakWhile) AbZ:AJ(  
break; g0rdF  
Br]VCp  
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//count++; PHDKx+$  
//if(count>4) lADi  
// siteStop(); uP|AP  
} oVoTnGNM6  
~W5fJd0  
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System.err.println("文件下载结束！"); UbC)XiO  
} RK'3b/T  
catch(Exception e){e.printStackTrace ();} TnM}|~V  
} =_%:9FnQ0  
`U2PlCf|  
rM[Ps=5  
//获得文件长度 +;Cq>1x,  
public long getFileSize() QV{Nq=%]  
{ t=XiSj\n  
int nFileLength = -1; 7X|&:V.s|  
try{ '(2G qX!  
URL url = new URL(siteInfoBean.getSSiteURL()); H.Jcp|k[;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K W04  
httpConnection.setRequestProperty("User-Agent","NetFox"); e6
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"~]9}KM}3W  
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int responseCode=httpConnection.getResponseCode(); `~@BU  
if(responseCode>=400) htM5Nm[g  
{ 9!2KpuWji  
processErrorCode(responseCode); {:6VJ0s\  
return -2; //-2 represent access is error WgE~H)_%  
} 4yRT!k}o  

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String sHeader; H@G7oK  
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for(int i=1;;i++) IFG`  
{ {y<_S]0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CX
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//Utility.log(in.readLine()); pNQd\nY|0  
sHeader=httpConnection.getHeaderFieldKey(i); Fi7pq2  
if(sHeader!=null) +"'h?7'C  
{ qmxkmO+Qur  
if(sHeader.equals("Content-Length")) ]t(g7lc}U  
{ vf5[x!4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BAm{Gb  
break; W!IK>IW"  
} i]Kq  
} .YS[Md{  
else 3kKXzIh  
break; _BR>- :Jr  
} m{b(^K9}  
} $#t&W&  
catch(IOException e){e.printStackTrace ();} w'L;`k;Q  
catch(Exception e){e.printStackTrace ();} $Q47>/CUc^  
<#`<Ys3b*!  
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Utility.log(nFileLength); g@nE7H1V  
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return nFileLength; #wC4$y<>  
} g1&GX(4[  
xss D2*l  
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//保存下载信息（文件指针位置） DK4V/>@8  
private void write_nPos() {{2ZWK 6|  
{ 61gZZM  
try{ #}k^g:l1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4AP<mo  
output.writeInt(nStartPos.length); C 
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for(int i=0;i<nStartPos.length;i++) 56TUh_  
{ (F_#LeJ|  
// output.writeLong(nPos); mg#+%v  
output.writeLong(fileSplitterFetch.nStartPos); u_:" u  
output.writeLong(fileSplitterFetch.nEndPos); A
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} C/]0jAAE7  
output.close(); @Vb-BC,  
} u
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catch(IOException e){e.printStackTrace ();} 3!*J;Y  
catch(Exception e){e.printStackTrace ();} (a)d7y.oo  
} CZbp}:|  
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6.K)uQgjmv  
//读取保存的下载信息（文件指针位置） E-!`6  
private void read_nPos() 2abWIw4  
{ M+nz~,![  
try{ N %0F[sY6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *!.'1J:YJ(  
int nCount = input.readInt(); a2p<HW;)m  
nStartPos = new long[nCount]; ((t8  
nEndPos = new long[nCount]; [>6:xGSe9X  
for(int i=0;i<nStartPos.length;i++) z?E:s.4F  
{ W%Ky#!\-  
nStartPos = input.readLong(); %} \@Wk~  
nEndPos = input.readLong(); uWMAXGL  
} r0S"}<8O  
input.close(); =\_MJ?A$  
} 2;6p2GNSh  
catch(IOException e){e.printStackTrace ();} NFc<%#H  
catch(Exception e){e.printStackTrace ();} 4pA(.<#A  
} 8HTV"60hTs  
|yQ3H)qB#  
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private void processErrorCode(int nErrorCode) *4+;Ey  
{ `Jz"rh-M  
System.err.println("Error Code : " + nErrorCode); h4.ZR={E  
} 4$vya+mAk5  
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@gs Kb*,  
//停止文件下载 wRUpQ~=B2  
public void siteStop() \.Q"fd?a_D  
{ ,=z8aiUu  
bStop = true; &a-:ZA@  
for(int i=0;i<nStartPos.length;i++) yjN|PqtSV  
fileSplitterFetch.splitterStop(); &.Yh_  
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} :^?ZVi59j  
} kqv>rA3  
//负责部分文件的抓取 ~@L$}Eu  
**FileSplitterFetch.java H VG'v>s@  
*/ 1kTJMtZG~  
package NetFox; b6oPnP_3P  
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import java.io.*; -zMXc"'C^k  
import java.net.*; t</Kel|D  
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public class FileSplitterFetch extends Thread { YceiP,!4?v  
2{**bArV  
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String sURL; //File URL ~])\xC  
long nStartPos; //File Snippet Start Position [#uX{!q'  
long nEndPos; //File Snippet End Position _<kE32Bb  
int nThreadID; //Thread's ID M
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boolean bDownOver = false; //Downing is over Q|+m)A4@  
boolean bStop = false; //Stop identical > NK?!!A_  
FileAccessI fileAccessI = null; //File Access interface ){R_o
5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .|KxQn}  
{ CI$F#j  
this.sURL = sURL; Q
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this.nStartPos = nStart; r'pFHX  
this.nEndPos = nEnd; 3"!2C,3c#  
nThreadID = id; '_@=9 \<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &RpQ2*4n  
} 6"eGd"  
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public void run() u ldea)  
{ xg\M9&J  
while(nStartPos < nEndPos && !bStop) RiaO`|1  
{ +;U}SR<  
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try{ J'^BxN&  
URL url = new URL(sURL); XC0G5rtB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 09%q
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httpConnection.setRequestProperty("User-Agent","NetFox"); "op1xto  
String sProperty = "bytes="+nStartPos+"-"; bHWy9-  
httpConnection.setRequestProperty("RANGE",sProperty); ?GB($D=Y'&  
Utility.log(sProperty); H*EQ%BLW^,  
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InputStream input = httpConnection.getInputStream(); noh3mi  
//logResponseHead(httpConnection); }+i ZY\t  
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= J).(E89  
byte[] b = new byte[1024]; tN";o\!}  
int nRead; 5|S|HZ8G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f![x7D$  
{ y%}Po)X]f  
nStartPos += fileAccessI.write(b,0,nRead); 9!gm
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//if(nThreadID == 1) 2~Gcoda  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wq F(  
} L.l%EcW=,  
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Utility.log("Thread " + nThreadID + " is over!"); H:d{Sru  
bDownOver = true; i+Ob1B@w
 
//nPos = fileAccessI.write (b,0,nRead); RyIr_:&-~  
} ,^:Zf|V  
catch(Exception e){e.printStackTrace ();} u0w2v+  
} N$p}rh#7{  
} VGWqy4m  
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1K09iB  
//打印回应的头信息 r7JILk  
public void logResponseHead(HttpURLConnection con) [)Xu60?Q  
{ p^5B_r:  
for(int i=1;;i++) E Jq=MP  
{ ruB&&C6)v  
String header=con.getHeaderFieldKey(i); 6\OSIxJZF  
if(header!=null) N!9DZEcm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g0cCw2S  
Utility.log(header+" : "+con.getHeaderField(header)); H Y.,f_m  
else cS4e}\q,  
break; o=q N+-N  
} o@EV>4e y  
} im*QaO%a4  
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public void splitterStop() g]X4)e]  
{ K ,f1c}  
bStop = true; W{1=O)w  
} JEU?@J71O  
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} F{bET  
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*ZK
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/* k-b_ <Tbo|  
**FileAccess.java _GI [SzD  
*//文件访问(定位，写) h"#^0$f  
package NetFox; `(W V pP?  
import java.io.*; s@^GjA[6+  
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public class FileAccessI implements Serializable{ 3M+hjc.  
+@usJkxul  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8 E.u3eS  
RandomAccessFile oSavedFile; Ij@YOt  
long nPos; N%_-5Q)so  
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public FileAccessI() throws IOException jVi''#F?f  
{ DWm$:M4z  
this("",0); qJ5Y}/r  
} L7q%u.nB1  
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public FileAccessI(String sName,long nPos) throws IOException d[-w&[iy  
{ kpxd+w  
oSavedFile = new RandomAccessFile(sName,"rw"); }4A+J"M4y  
this.nPos = nPos; QmbD%kW`3  
oSavedFile.seek(nPos); y5|`B(  
} WH/
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%$!}MxUM  
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public synchronized int write(byte[] b,int nStart,int nLen) [M Z'i/  
{ \qNj?;B  
int n = -1; X/2Xr(z"k  
try{ BU<A+Pe>  
oSavedFile.write(b,nStart,nLen); [KVBT;q6  
n = nLen; (!W:-|[K
\  
} 3~a!h3.f  
catch(IOException e) ?J%$;"q  
{ +\\,FO_  
e.printStackTrace (); Vyu0OiGcR  
} !yG{`#NZZ  
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r,L#JR w#-  
return n; :&&Ps4\Sq  
} FTtYzKX(bv  
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} bn~=d@'  
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/* #wk'&XsC#z  
**SiteInfoBean.java >m44U 9  
*/ F4YCU$V  
package NetFox; ]wER&/v"  
Nt$/JBB[$  
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public class SiteInfoBean { 4WzB=C(f  
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private String sSiteURL; //Site's URL Ip
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private String sFilePath; //Saved File's Path ZiSy&r:(  
private String sFileName; //Saved File's Name l`[*b_ Xt  
private int nSplitter; //Count of Splited Downloading File ~Q0jz/#c  
UyEyk$6SU  
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public SiteInfoBean() <,`=m|z9k  
{//nSplitter的缺省值为5 .NiPaUzc<  
//default value of nSplitter is 5 IgG@v9'  
this("","","",5); Pi40w+/  
} : \:jIP  
)DI/y1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RI')iz?  
{ u;F++$=  
sSiteURL= sURL; DSM,dO'  
sFilePath = sPath; /H:'(W_b;  
sFileName = sName; B&0-~o3WP  
this.nSplitter = nSpiltter; Hh(_sewo  
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} c_yf=  
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public String getSSiteURL() Vx~[;*{,C9  
{ H/|Mq#K  
return sSiteURL; i jg'X#E  
} $f7#p4;}(  
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public void setSSiteURL(String value) 3G~ T_J&  
{ vh"zYl`  
sSiteURL = value; 0mF3Vs`-Q  
} u%Hegqn  
%t([  
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public String getSFilePath() 1,p7Sl^h  
{ yxf|Njo0  
return sFilePath; Sl/[9-a)  
} ' &^:@V  
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V&-pgxf;  
public void setSFilePath(String value) ~]*P/'-{#  
{ V)mRG`L  
sFilePath = value; jQFAlO(E':  
} HpiP"Sl  
 O3bo3Cm$  
7{ (t_N>  
public String getSFileName() bJ*jJl x  
{ 4yV}4f$q  
return sFileName; uLD%M av  
} <S:SIaf0  
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public void setSFileName(String value) 6Z]* ce<r  
{ Qr6[h!  
sFileName = value; [8EzyB>fH  
} aze}koNE  
#eD@sEn  
<5?.s< y$"  
public int getNSplitter() cT'D2Yeq  
{ 9+)5#!0  
return nSplitter; ?B.>VnYZ/a  
} NRe{0U}nO  
R*3x{DNL  
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public void setNSplitter(int nCount) _&_#uV<WG0  
{ ;HtHN K(o  
nSplitter = nCount; PE4#dx^  
} g]PmmK_L  
} ?B3   
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/* tn&~~G~#  
**Utility.java >0z(+}]3z  
*/ H,bYzWsrPo  
package NetFox; |dcRDOTe  
jHBzZ!<  
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public class Utility { Hg(%gT  
;WxE0Q:!~  
'
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public Utility() lArYlR}  
{ W9nmTz\8  
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} ^t,sehpR:l  
N]f"+  
//线程睡眠 ;/T=ctIs  
public static void sleep(int nSecond) h8OmO5/H  
{ w64/$  
try{ &qKJN#NM@  
Thread.sleep(nSecond); 32j@6!  
} ',`GdfAsH  
catch(Exception e) X&R
,-^  
{ l'TM^B)`c  
e.printStackTrace (); |t](4  
} Kgh@.Ir  
} d/oxRzk'L  
=s3
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//日志 ], Xva`"  
public static void log(String sMsg) 5H8]N#Y&  
{ LA?h+)  
System.err.println(sMsg); &+]x  
} $}k
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x xMV2&,Jq  
public static void log(int sMsg) x`:zC#  
{ _4H 9rPhf  
System.err.println(sMsg); p1^k4G  
} rq=D[vX\N(  
} ]3UEju8$  
%^1@c f?.  
UOh%"h  
/* ,
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**TestMethod.java OX|nYTp  
*/ DdO$&/`)YP  
package NetFox; *2wFLh  
-U'3kaX5
<  
YMGzO  
public class TestMethod { iBlZw%zKP  
ig:E`Fe@  
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public TestMethod() y"5>O|`  
{ ///xx/weblogic60b2_win.exe !=sM `(=~  
try{ H<6TN^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )qxZHV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R`%C]uG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0|mF /  
fileFetch.start(); 9WE_9$<V  
} +-8S,Rg@   
catch(Exception e){e.printStackTrace ();} df@r2 /Y  
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} 7-p9IFcA  
3RSiu}  
d"h*yH@  
public static void main(String[] args) ^Bkwbj  
{ POZ5W)F(  
new TestMethod(); s+9q`k^  
} A}./ ;[  
} 8v eG^o  
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