http断点续传简单实现（java)

/* r8 Zyld_@  
**SiteFileFetch.java 17n+4J]  
*/ PK2R
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package NetFox; pRiH,:\  
import java.io.*; }[KDE{,V  
import java.net.*; o! 2n}C  
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public class SiteFileFetch extends Thread { g]==!!^<D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3I;xU(rv  
long[] nStartPos; //开始位置 @`IXu$Wm(  
long[] nEndPos; //结束位置 rTP5-4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DYT@BiW{  
long nFileLength; //文件长度 }1a<{
&  
boolean bFirst = true; //是否第一次取文件 cXOje"5i  
boolean bStop = false; //停止标志 G.-h=DT]  
File tmpFile; //文件下载的临时信息 +3/k/W  
DataOutputStream output; //输出到文件的输出流 9zoT6QP4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }&Wp3EWw  
public SiteFileFetch(SiteInfoBean bean) throws IOException (^DLCP#*  
{ wO2V%v^bp  
siteInfoBean = bean; gqP-E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i14[3bPLk!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D4=..;  
if(tmpFile.exists ()) ,>bGbx  
{ SE,o7_k'S  
bFirst = false; zp7V\W; &  
read_nPos(); W"b&M%y|  
} 4|zdXS  
else L,Ao.?j  
{ c N02roQl  
nStartPos = new long[bean.getNSplitter()]; p3M#XC_H]  
nEndPos = new long[bean.getNSplitter()]; Kcs
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} 5u2{n rc  
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public void run() d\~p5_5.  
{ L.C ^E7;Z_  
//获得文件长度 z
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//分割文件 (v|r'B9b  
//实例FileSplitterFetch "rme~
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//启动FileSplitterFetch线程 g".d"d{  
//等待子线程返回 :V&N\>Wo  
try{ ,vY)n6  
if(bFirst) 1%$d D2  
{ JP{UgcaF  
nFileLength = getFileSize(); ?TvQ"Y}k  
if(nFileLength == -1) Z~r[;={,  
{
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System.err.println("File Length is not known!"); l
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} <U@P=G<t  
else if(nFileLength == -2) $7Jfb<y  
{ C>*5=p|T  
System.err.println("File is not access!"); *ZGX-+{  
} N=OS\pz  
else )>(L{y|uYX  
{ gKmX^A5<  
for(int i=0;i<nStartPos.length;i++) GE%2/z p  
{ u~" si
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); UppBnw  
} xj0cgK|!  
for(int i=0;i<nEndPos.length-1;i++) PV?]UUc'n<  
{ +O)]^"TG  
nEndPos = nStartPos[i+1]; {F'Az1^I=  
} 3LKB;  
nEndPos[nEndPos.length-1] = nFileLength; Up<~
0  
} \.c]kG>k-  
} M6J/mOVx5  
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//启动子线程 ~_'0]P\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y.q>EUSH  
for(int i=0;i<nStartPos.length;i++) }0$mn)*k  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N*~_\x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z`rK\Bc  
nStartPos,nEndPos,i); C1V# ?03eI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k]Zo-xh4  
fileSplitterFetch.start(); p?;-!TUv  
} {T&v2u#S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bFSlf5*H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,*7H|de7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Am=wEu[b  
nEndPos = " + nFileLength); \@i=)dA  
// fileSplitterFetch[nPos.length-1].start(); =K:(&6f<t  
\ZS\i4  
w TlGJ$D0  
//等待子线程结束 sYI~dU2H  
//int count = 0; QjLji+L  
//是否结束while循环 Wdo#?@m  
boolean breakWhile = false; ,E&Bn8L~O  
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while(!bStop) -n$ewV  
{ r:-WzH(Ms  
write_nPos(); ,*dzJT$k  
Utility.sleep(500); On4w/L9L5  
breakWhile = true; \k;U}Te<  
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for(int i=0;i<nStartPos.length;i++) h2% J/69  
{ uyFn}y62  
if(!fileSplitterFetch.bDownOver) B s,as  
{ NgHpIonC  
breakWhile = false; ,>u=gA&}  
break; VpSEVd:n  
} CN/IH  
} B20_ig:  
if(breakWhile) h'l^g%;  
break; !h>D;k6 e  
l)Zs-V!M^\  
|6%.VY2b  
//count++; `@|w>8bMz{  
//if(count>4) #XI"@pD  
// siteStop(); hq?jdNy :  
} rs:Q%V ^  
a=+T95ulDy  
khAqYu")  
System.err.println("文件下载结束！"); NhA#bn9y?  
} noC?k }M  
catch(Exception e){e.printStackTrace ();} ^YKy9zkTl  
} Ziz=]D_  
y? "@v.  
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//获得文件长度 ?U_9{}r  
public long getFileSize() m"Qq{p|'  
{ .Pw%DZ'  
int nFileLength = -1; G;TsMq  
try{ U<47WfcW  
URL url = new URL(siteInfoBean.getSSiteURL()); .^[_V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nJJs%@y  
httpConnection.setRequestProperty("User-Agent","NetFox"); ''S&e  
7yI`e*EOD  
|y"jZT6R}t  
int responseCode=httpConnection.getResponseCode(); wGJjA
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if(responseCode>=400) .0|
=[|  
{ WJ+>e+  
processErrorCode(responseCode); kq-6HDR  
return -2; //-2 represent access is error ug*D52?  
} K=6UK%y A  
VXm[-  
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String sHeader; \iU]s\{).  
8~ #M{}  
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for(int i=1;;i++) _8><| 3d  
{ )NT5yF,m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n.hElgkUOr  
//Utility.log(in.readLine()); 59*M"1['Q  
sHeader=httpConnection.getHeaderFieldKey(i); KrKu7]If6#  
if(sHeader!=null) ;;V\"7q'  
{ KWhZ +i`  
if(sHeader.equals("Content-Length")) U,;xZe  
{ H"CUZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6;oe=Q
:Q  
break; ;GsQR+en
 
} /N)5 3!LT  
} 8LJ{i%  
else !@g)10u  
break; &|5GB3H=  
} },c,30V'  
} IfV 3fJ7  
catch(IOException e){e.printStackTrace ();} kWL.ewTiex  
catch(Exception e){e.printStackTrace ();} 4;KWG}~[o  
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Utility.log(nFileLength); 1H{jy^sP7  
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return nFileLength; 7Kf}O6nE  
} (~s|=Hxq|-  
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//保存下载信息（文件指针位置） 8o-bd_  
private void write_nPos() _:J*Cm[q  
{
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try{ [@"wd_f{l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Owf.f;QR  
output.writeInt(nStartPos.length); )1F<6R  
for(int i=0;i<nStartPos.length;i++) 'C?NJ~MN  
{ Qw)9r{f  
// output.writeLong(nPos); mlu 3K  
output.writeLong(fileSplitterFetch.nStartPos); [!"XcFY:a  
output.writeLong(fileSplitterFetch.nEndPos); \cuS>G  
} ULBg{e?l8  
output.close(); o-eKAkh  
} A^Cj1:,  
catch(IOException e){e.printStackTrace ();} RT*5d;l0  
catch(Exception e){e.printStackTrace ();} l@~LV}BI  
} 3HiFISA*  
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2t1I3yA'{z  
//读取保存的下载信息（文件指针位置） `/Y+1 aD  
private void read_nPos() q'S =Eav8  
{ cd.brM  
try{ .%xzT J=!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %_gho  
int nCount = input.readInt(); >q7 %UK]&  
nStartPos = new long[nCount]; UAYd?r  
nEndPos = new long[nCount]; 1BTIJ Gw  
for(int i=0;i<nStartPos.length;i++) 6C-YyI#s#  
{ UG[e//m  
nStartPos = input.readLong(); -50AX1h31:  
nEndPos = input.readLong(); /-Qv?"  
} p25Fn`
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input.close(); +,flE=5]s  
} >+9JD%]x]  
catch(IOException e){e.printStackTrace ();} d"THt}
  
catch(Exception e){e.printStackTrace ();} Q9>U1]\  
} (f1M'w/OD  
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private void processErrorCode(int nErrorCode) H[W
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{ g-)mav  
System.err.println("Error Code : " + nErrorCode); cT'w=  
} Vk}49O<K/  
$3P`DJo  
(> "QVxr  
//停止文件下载 w|Aqqe  
public void siteStop() sbsu(Sz+  
{ )0CQP  
bStop = true; FGanxv@15  
for(int i=0;i<nStartPos.length;i++) 3h=8"lRc  
fileSplitterFetch.splitterStop(); "pvZ,l>8f  
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} M}F~_S0h  
} }ot"Sx\.  
//负责部分文件的抓取 5cfA;(H  
**FileSplitterFetch.java lZ+!H=`  
*/ --k:a$Nt  
package NetFox; /i
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import java.io.*; -|_ir-j  
import java.net.*; ~1(j&&kXet  
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public class FileSplitterFetch extends Thread { G$JFuz)|  
oRY!\ADR  
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String sURL; //File URL \7 a4uc  
long nStartPos; //File Snippet Start Position J)x3\[}Ye  
long nEndPos; //File Snippet End Position c{3rl;Cs  
int nThreadID; //Thread's ID Kn}ub+
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boolean bDownOver = false; //Downing is over PEXq:TA  
boolean bStop = false; //Stop identical 9%DT0.D}$j  
FileAccessI fileAccessI = null; //File Access interface H7&xLYQ2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Jh@_9/?  
{ g1[&c+=U`P  
this.sURL = sURL; 9K"JYJ q2  
this.nStartPos = nStart; >J>V% 7  
this.nEndPos = nEnd; }KB[B  
nThreadID = id; .b>TK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  v[,Src  
} 8<&EvOk  
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public void run() \U
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{ }DIF%}UK\  
while(nStartPos < nEndPos && !bStop) "QY1.:o<(  
{ B;t=B_oK  
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try{ FjKq%.=#  
URL url = new URL(sURL); /L~m#HxWU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hC<14  
httpConnection.setRequestProperty("User-Agent","NetFox"); H{zPft  
String sProperty = "bytes="+nStartPos+"-"; :7b-$fm  
httpConnection.setRequestProperty("RANGE",sProperty); ;#QhQx  
Utility.log(sProperty); &O1v,$}'  
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InputStream input = httpConnection.getInputStream(); T@48qg  
//logResponseHead(httpConnection); q)I|2~Q c^  
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byte[] b = new byte[1024]; R}{GwbF_\  
int nRead; %$mjJw<|&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;e{5)@h$  
{ IgX4.]W5  
nStartPos += fileAccessI.write(b,0,nRead); 5K.+CO<  
//if(nThreadID == 1) v'9m7$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AK/:I>M  
} wK*PD&nN  
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Utility.log("Thread " + nThreadID + " is over!"); R@`rT*lJ  
bDownOver = true; =_-C%<4  
//nPos = fileAccessI.write (b,0,nRead); rla:<6tt  
} kQIw/@WC  
catch(Exception e){e.printStackTrace ();} 2
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} vrIV%l=  
} kC$I2[t!  
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bkv/I{C>?  
//打印回应的头信息 ~j&?/{7I  
public void logResponseHead(HttpURLConnection con) ZBM!MSf:  
{ ->oz#   
for(int i=1;;i++) P6Xp<^%E  
{ w|Q
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String header=con.getHeaderFieldKey(i); S+T|a:]\7  
if(header!=null) YoSQN
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); @ss):FwA  
Utility.log(header+" : "+con.getHeaderField(header)); +R\~3uj[7  
else |63Y >U"  
break; EXbTCT}`x  
} p\D >z("  
} F(4yS2h(  

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public void splitterStop() v3
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{ 5*j:K&R-.K  
bStop = true; A*0*sZ0  
} vm}G[  
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{D(,ft;s^  
} yazZw}};  
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/* ScJu_Af  
**FileAccess.java [W(Y3yyY  
*//文件访问(定位，写) K&S@F!#g  
package NetFox; L82NP)St  
import java.io.*; x# 8IZ  
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public class FileAccessI implements Serializable{ RV92qn B  
\+]O*Bm&`8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SLh~_ 5  
RandomAccessFile oSavedFile; 3"tg+DncC  
long nPos; <^sAY P|  
`7_n}8NVC  
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public FileAccessI() throws IOException Xz* tbW#  
{ _IKQ36=  
this("",0); 8A_TIyh?  
} Q9q9<J7j$  
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public FileAccessI(String sName,long nPos) throws IOException )$F6  
{ ^Kum%<[i  
oSavedFile = new RandomAccessFile(sName,"rw"); Cha?7F[xL  
this.nPos = nPos; |wJ),h8/  
oSavedFile.seek(nPos); i ~P91  
} cJV!>0ua  
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public synchronized int write(byte[] b,int nStart,int nLen) 2w7@u/OC'  
{ 9BurjG1k?  
int n = -1; KM@`YV
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try{ yh$ ~*UV  
oSavedFile.write(b,nStart,nLen); ?a8nz, zb  
n = nLen; |vT=Nnu  
} SmvwhX  
catch(IOException e) x"!#_0TT}  
{ GiFf0c 9  
e.printStackTrace (); Qv=Bq{N  
} ?e2Y`0  
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return n; C7T;;1P?  
} 8ZzU^x  
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@OrXbG7&>#  
} Z%A<#%   
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7TR'zW2W  
/* ~.!?5(AH8z  
**SiteInfoBean.java Q!Msy<v  
*/ >sB=\  
package NetFox; LsUFz_  
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8Q)y%7{6  
public class SiteInfoBean { xQZMCd  
<vO8_2,V-  
e4?<GT  
private String sSiteURL; //Site's URL 5auL<Pq  
private String sFilePath; //Saved File's Path 5Bzuj`  
private String sFileName; //Saved File's Name Ds;Rb6WcnY  
private int nSplitter; //Count of Splited Downloading File E)RI!0Ra  
*%z<P~}  
J
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public SiteInfoBean() XC57];-  
{//nSplitter的缺省值为5 U8Cw7u2  
//default value of nSplitter is 5 pC55Ec<  
this("","","",5); +q4W0  
} U_.n=d~B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 01UqDdoj  
{ ysQEJm^|-u  
sSiteURL= sURL; F9ZOSL 8Q  
sFilePath = sPath; (4E.Li<O  
sFileName = sName; }u38:(^`ai  
this.nSplitter = nSpiltter; \E>%W  
/5a$@%  
g%Th_=qy  
} Z5{*? 2  
4UkP:Vz:  
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public String getSSiteURL() Q';\tGy  
{ l;"ub^AH  
return sSiteURL; ghE?8&@ iq  
} 1e+h9|hGYw  
]
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public void setSSiteURL(String value) gs^UR6 D,  
{ ?w c3+?\J  
sSiteURL = value; dn:|m^<)  
} g: H[#I  
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public String getSFilePath() QySca(1tN  
{ Bh.6:9{  
return sFilePath; }bj,&c  
} eB}
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public void setSFilePath(String value) 4#'^\5  
{ )dzjz%B)  
sFilePath = value; s%0[
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} p~k`Z^xY$  
o} bj!h]N  
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public String getSFileName() k~W;TCJs
  
{
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return sFileName; !X#3
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} EeF n{_  
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public void setSFileName(String value) %\s#e  
{ "O"^\f  
sFileName = value; ^.><t+tM  
} hVQ+ J!qD  
S^sW.(I  
FB^dp}  
public int getNSplitter() 6:7:NIl:  
{ y:(C=*^<t  
return nSplitter; B@~eBU,$  
} wft:eQ  
[fJFH^&?hr  
83O^e&Bt  
public void setNSplitter(int nCount) Q& unA3  
{ bvxxE/?Ni  
nSplitter = nCount; [^"(%{H  
} D%";!7u  
} 1.cUolnr  
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/* Y9c9/_CSj  
**Utility.java IWbp^l+!t  
*/ k)4lX|}Vm  
package NetFox; |2c!t$O@v  
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public class Utility { /hj9Q!  
M
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',xsUgk  
public Utility() H
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{ ]ge^J3az$u  
:_[cT,3  
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} aDJjVD  
<`VJU2  
//线程睡眠 G^eFS;  
public static void sleep(int nSecond) J&0wl]w|O%  
{ Ga/\kO)x_  
try{ '_yk_[/  
Thread.sleep(nSecond); e+=G-u5}-  
} pU)3*9?cIl  
catch(Exception e) !j\&BAxTEk  
{ {bsr 9.k(  
e.printStackTrace (); H_nOE(i<z  
} =v#A&IPA'  
} J$=b&$I(  
l8 2uK"M  
//日志 d=u%"36y  
public static void log(String sMsg) z@S8H6jM)S  
{ =R8.QBVdN  
System.err.println(sMsg); sMpC4E  
} /)OO)B-r  
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QBT-
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public static void log(int sMsg) HFCFEamBMP  
{ 'MM~~:  
System.err.println(sMsg); Q9'V&jm  
} l\l]9Z6%  
}
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/* U3iy
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**TestMethod.java ng)yCa_Ny  
*/ V?=zuB?'  
package NetFox; %!/liS  
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public class TestMethod { +OuG!3+w  
E$zq8-p|  
(HD>vNha1  
public TestMethod() :zy'hu;  
{ ///xx/weblogic60b2_win.exe t;PnjCD<`  
try{ ~w}[ ._'#M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8Nq Iz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jc.Uh9Kc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iKTU28x  
fileFetch.start(); K`83C`w.  
} 5oyMR_yl  
catch(Exception e){e.printStackTrace ();} lcJumV=%>  
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'cc4Y~0s  
} r
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public static void main(String[] args) 1s\hJATfz  
{ y:Ab5/bHy  
new TestMethod(); I*ni)Px  
} VNot4 62L  
} l\y*wr`  
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