http断点续传简单实现（java)

/* A'T! og|5  
**SiteFileFetch.java fsu'W]f  
*/ Zx6BK=4G  
package NetFox; 3mWN?fC  
import java.io.*; :HC{6W`$  
import java.net.*; ygHNAQG~  
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public class SiteFileFetch extends Thread { %O-wMl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2B|3`trY4x  
long[] nStartPos; //开始位置 U}NNbGQj  
long[] nEndPos; //结束位置 |"arVde  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TA*49Qp  
long nFileLength; //文件长度 MEE]6nU  
boolean bFirst = true; //是否第一次取文件 *ZHk^d:  
boolean bStop = false; //停止标志 aX!J0
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File tmpFile; //文件下载的临时信息 Ty>`rn  
DataOutputStream output; //输出到文件的输出流 zK}.Bhj#  
~be&T:7.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &A>J>b  
public SiteFileFetch(SiteInfoBean bean) throws IOException !HFwQGP.Y  
{ .d;/6HD[y  
siteInfoBean = bean; %tpjy,
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ) E5ax~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }wn GOr  
if(tmpFile.exists ()) Li}yK[\]  
{ jd#{66:  
bFirst = false; |m~|  
read_nPos(); >%{h_5  
} U7O2.y+  
else eb7`R81G  
{ H&I0\upd  
nStartPos = new long[bean.getNSplitter()]; -k'=s{iy  
nEndPos = new long[bean.getNSplitter()]; NWFZ:h@v  
} ;kdJxxUox  
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} C0e< _6p=  
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public void run() uu HWN|  
{ 7#Mi`W  
//获得文件长度 N52N ^X>  
//分割文件 |>m@]s7Z  
//实例FileSplitterFetch OA[w|Tt  
//启动FileSplitterFetch线程 Oa{M9d,l  
//等待子线程返回 ?k/Uw'J4u/  
try{ R5Ti|k.~Y"  
if(bFirst) 778a)ZOzb  
{ dP )YPy_`  
nFileLength = getFileSize(); _TH'v:C  
if(nFileLength == -1) Fm:Ri$iT  
{ =*t)@bn  
System.err.println("File Length is not known!"); 9n1
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} W;2y.2*  
else if(nFileLength == -2) Xod#$'M>  
{ L,n'G%  
System.err.println("File is not access!"); %ePInpb  
} u)%J5TR.Y  
else azN<]u@.  
{ S);bcowf_  
for(int i=0;i<nStartPos.length;i++) PM,I?lJ,  
{ 8g$pfHt|e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2: fSn&*/>  
} !s
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for(int i=0;i<nEndPos.length-1;i++) fy7]
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{ yYF%U7N/n  
nEndPos = nStartPos[i+1]; y "gYv  
} IpHGit28  
nEndPos[nEndPos.length-1] = nFileLength; L\!Pa+Iod  
} -G
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} )%P!<|s:5  
^dRB(E}|)  
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//启动子线程 A+>+XA'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ge*f<#|0U-  
for(int i=0;i<nStartPos.length;i++) {o AJL  
{ h ~v8Q_6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S9-FKjU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rqSeh/<iD  
nStartPos,nEndPos,i); [WuN?H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3(jI  
fileSplitterFetch.start(); Z+JPxe#7  
} #TXgV0\F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |}=xA%)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'jqkDPn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZE#A?5lb  
nEndPos = " + nFileLength); 5V8WSnO  
// fileSplitterFetch[nPos.length-1].start(); ~Cm_=[  
??)IPRv?yF  
WQK ~;GV-  
//等待子线程结束 ~}+F$&  
//int count = 0; ]9F$/M#  
//是否结束while循环 LS <\%A}  
boolean breakWhile = false; =HH}E/9z  
"KS
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while(!bStop) /5pVzv+rm  
{ Sjv_% C$  
write_nPos(); 67?O}~jbG  
Utility.sleep(500); V\vt!wBcB  
breakWhile = true; D.su^m_1  
LB$#]
Z  
16Cd0[h?  
for(int i=0;i<nStartPos.length;i++) imC>T!-7  
{ \2#7B8  
if(!fileSplitterFetch.bDownOver) plN:QS$  
{ 0QcC5y;  
breakWhile = false; N"L@  
break; ~U}0=lRVS  
} )
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} #?u#=]  
if(breakWhile) s
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break; sQwRlx  
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//count++; VN]70LFz*i  
//if(count>4) c'O"</  
// siteStop(); '(fQtQ%  
} ~+ [T{{  
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System.err.println("文件下载结束！"); J;wDvt]]1  
} (J}tCqP  
catch(Exception e){e.printStackTrace ();} NAgm?d  
} K-<<s  
.|UIZwW0  
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//获得文件长度 !A":L0[7n  
public long getFileSize() M$,4B  
{ e>J.r("f  
int nFileLength = -1; \8Y62  
try{ C@b-)In  
URL url = new URL(siteInfoBean.getSSiteURL()); 0
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SJ*qgI?}T  
httpConnection.setRequestProperty("User-Agent","NetFox"); vX30Ijm  

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int responseCode=httpConnection.getResponseCode();  9q[d?1  
if(responseCode>=400) d RIuA)0s  
{
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processErrorCode(responseCode); >v#6SDg  
return -2; //-2 represent access is error ({$>o]<h  
} sU7fVke1   
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String sHeader; .VXadgM  
?uh%WN6nU]  
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for(int i=1;;i++) Kt3T~k  
{ =j^>sg]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jI/#NCKE  
//Utility.log(in.readLine()); {iXQUj  
sHeader=httpConnection.getHeaderFieldKey(i); *)bh6b=7  
if(sHeader!=null) TdeHs{|  
{ SDu%rr7sQ  
if(sHeader.equals("Content-Length")) >zX`qv&>  
{ \%}w7
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q"0_Px9P  
break; 7<0oK|~c#  
} `|p8zV  
} 0d/ f4  
else zX8'OoEH*9  
break; R!>l7p/|H)  
} }Jo}K)>!  
} EG!Nsb^,  
catch(IOException e){e.printStackTrace ();} TUN6`/"  
catch(Exception e){e.printStackTrace ();} b Bkg/p]  
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Utility.log(nFileLength); \=c@  
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return nFileLength; 8}aS
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} @{@DGc  
0ky3rFSh1  
;>CM1  
//保存下载信息（文件指针位置） L-`?=- 9`  
private void write_nPos() /_Fi4wZ  
{ .R^q$U~v3  
try{ ^tL]QE?|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KBI36=UV  
output.writeInt(nStartPos.length); ^!6T,7B B  
for(int i=0;i<nStartPos.length;i++) Dc9Fb^]QOG  
{ _};T:GOT  
// output.writeLong(nPos); byHXRA)39  
output.writeLong(fileSplitterFetch.nStartPos); x-T7 tr&(  
output.writeLong(fileSplitterFetch.nEndPos); k $E{'Dv  
} ZMEYF!jN  
output.close(); =>*9"k%m  
} LIRL`xU7  
catch(IOException e){e.printStackTrace ();} ~.Er  
catch(Exception e){e.printStackTrace ();} PNpH)'C|
 
} x75 3o\u!  
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//读取保存的下载信息（文件指针位置） &;[0.:;  
private void read_nPos() mW)C=X%  
{ _SrkR7  
try{ V9;O1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vv1W<X0e<  
int nCount = input.readInt(); & &:ZY4`  
nStartPos = new long[nCount]; ~}Z'/zCZf  
nEndPos = new long[nCount]; a/Cc.s   
for(int i=0;i<nStartPos.length;i++) T^@P.zX  
{ -+n?Q;  
nStartPos = input.readLong(); 6C- !^8[f  
nEndPos = input.readLong(); *#Iqz9X.Y3  
} o(YF`;OhvS  
input.close(); PG*FIRDb  
} -:Jn|=  
catch(IOException e){e.printStackTrace ();} ui&^ m,  
catch(Exception e){e.printStackTrace ();} n==+NL  
} Es&'c1$^s  
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private void processErrorCode(int nErrorCode) xHaoSs*C9  
{ O7xBMqMf  
System.err.println("Error Code : " + nErrorCode); R 5Cy%  
} d=a$Gd_$  
?j$*a7[w  
8]&lUMaqVZ  
//停止文件下载 *cc|(EM  
public void siteStop() nE"0?VNW$  
{ W C3b_ia  
bStop = true; |dqv
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for(int i=0;i<nStartPos.length;i++) +zzS  
fileSplitterFetch.splitterStop(); eQsoZQA1  
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} C/!8NV1:4  
} \2AXW@xE  
//负责部分文件的抓取 4.'KT;[_1/  
**FileSplitterFetch.java 33w(Pw  
*/ MKr:a]-'f~  
package NetFox; ]|4mD3O  
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import java.io.*; UdX aC= Q  
import java.net.*; kA(q-Re$B*  
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public class FileSplitterFetch extends Thread { cP[]\r+Kj  
et :v4^*f  
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String sURL; //File URL Zbjj>*2%^  
long nStartPos; //File Snippet Start Position Vr<ypyC  
long nEndPos; //File Snippet End Position AV?<D.<  
int nThreadID; //Thread's ID ]@7]mu:oL  
boolean bDownOver = false; //Downing is over :@q9ll`6u  
boolean bStop = false; //Stop identical Y^CbpG&-vC  
FileAccessI fileAccessI = null; //File Access interface +hd1|qa4  
.@;,'Xw1~  
^1NtvQe@Y\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1@A*Jj[R%  
{ parC~)b_  
this.sURL = sURL; w\3'wD!  
this.nStartPos = nStart; {>=#7e-]  
this.nEndPos = nEnd; YK|Y^TU^  
nThreadID = id; &)|3OJ'o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b{Kw.?85  
} 7Om)uUjU4  
|A@Gch fd  
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public void run() d<l
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{ Y/w) V
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while(nStartPos < nEndPos && !bStop) h\^> s$  
{ wq"AWyu  
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try{ G0eJ<*|_ 3  
URL url = new URL(sURL); ;j/-
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yD!V;?EnK  
httpConnection.setRequestProperty("User-Agent","NetFox"); ()+;KF8  
String sProperty = "bytes="+nStartPos+"-"; R0*+GIRA(  
httpConnection.setRequestProperty("RANGE",sProperty); Ctxx.MM  
Utility.log(sProperty); v]HiG_C  
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U-EX)S^T[{  
InputStream input = httpConnection.getInputStream(); C&ivjFf  
//logResponseHead(httpConnection); DqHVc)9  
,/g\;#:{@]  
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byte[] b = new byte[1024]; v#`Wf}G  
int nRead; <ST#< $%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `'`T'
+0  
{ jq&$YmWp  
nStartPos += fileAccessI.write(b,0,nRead); wp,z~raaS  
//if(nThreadID == 1) \HOOWaapN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RKP->@Gs  
} ~!!>`x  
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Utility.log("Thread " + nThreadID + " is over!"); _
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bDownOver = true; $V)LGu2(m  
//nPos = fileAccessI.write (b,0,nRead); 
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} N+PW,a  
catch(Exception e){e.printStackTrace ();} hexq]'R  
} TPds)osZT  
} E#FyL>:.h  
_ QM  
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//打印回应的头信息 `8TM<az-L  
public void logResponseHead(HttpURLConnection con) [hS?d.D   
{ [#td  
for(int i=1;;i++) 0\jOg  
{ Tf"DpA!_  
String header=con.getHeaderFieldKey(i); `B6{y9J6  
if(header!=null) -j[n^y'v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Tc)T0dRP  
Utility.log(header+" : "+con.getHeaderField(header)); LxVd7r VY6  
else L/GM~*Xp(O  
break; WJU` g  
} ;NRT a*  
} ~]/X,Cf  
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public void splitterStop() UUY-EC7X  
{ <E BgHD)  
bStop = true; @WU_GQas3  
} FV$= l %  
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} 4ij`  
;?2vW8{p<  
:*&wnQMKR  
/* o
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**FileAccess.java ok\+$+$ju  
*//文件访问(定位，写) {7eKv+30  
package NetFox; P+3G*M=}  
import java.io.*; '{cN~A2b4  
Bw*z4qb{yH  
''BP4=r5n  
public class FileAccessI implements Serializable{ vo`wYJ3W  
].dTEzL9X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !icpfxOpjQ  
RandomAccessFile oSavedFile; ^MJGY,r6b  
long nPos; {|xwvTlJ  
0uU%jN$  
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public FileAccessI() throws IOException B@zJ\Ir[  
{ pN0c'COy^  
this("",0); qqzQKN  
} r$v?[x>+K  
&ApJ'uC  
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public FileAccessI(String sName,long nPos) throws IOException DJQ]NY|  
{ j5'Jp}  
oSavedFile = new RandomAccessFile(sName,"rw"); Xq>e]#gR  
this.nPos = nPos; @su{Uno8/  
oSavedFile.seek(nPos); g=Qga09  
} NxXVW  
oLr"8R\d>t  
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public synchronized int write(byte[] b,int nStart,int nLen) J82{PfQ"  
{ lIFt/  
int n = -1; t^C
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try{ @>9
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oSavedFile.write(b,nStart,nLen); mLkZ4OZ  
n = nLen; 4G>|It  
} 3(5RUI-  
catch(IOException e) 9)l_(*F  
{ .@6]_h;  
e.printStackTrace (); ax^${s|{-  
} K%pmE?%,8  
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z}Z`kq+C  
return n; hx^a&"  
} \PLV]%3,  
9>i6oF]Oq  
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} /M3D[aR<d  
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/* jYy0^)6X(  
**SiteInfoBean.java 5dgBSL$A}]  
*/ MtYP3:  
package NetFox; nUd\4;J#  
6gKOpa  
/B!m|)h5~  
public class SiteInfoBean { tH'VV-!MZ  
*cf"l  
\9}5}X_x.  
private String sSiteURL; //Site's URL WD\{Sdx:r  
private String sFilePath; //Saved File's Path -1_Z*?
=-  
private String sFileName; //Saved File's Name ^ Wl/  
private int nSplitter; //Count of Splited Downloading File xF/DYXC{8  
N
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public SiteInfoBean() }-L@AC/\#  
{//nSplitter的缺省值为5 WvJ?e  
//default value of nSplitter is 5 +E [bLz^  
this("","","",5); RE.@ +A  
} p&4n3%(R@  
Nb#7&_f=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;:|KfXiC8  
{ 2Y4&Sba^Y  
sSiteURL= sURL; <!N;(nZ9}O  
sFilePath = sPath; _B1uE2j9  
sFileName = sName; +wUhB\F *  
this.nSplitter = nSpiltter; w+37'vQ  
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} H n!vTB  
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public String getSSiteURL() 1!`768  
{ PbPP1G')  
return sSiteURL; 668bJ.M\O  
} :(b3)K  
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public void setSSiteURL(String value) =Yj[MVn  
{ +=h!?<*C8  
sSiteURL = value; GzXP  
} "J5Pwvs-  
4) 3pa*  
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public String getSFilePath() \z`d}\3(R  
{ )M N yOj  
return sFilePath; zsXH{atY  
} ]2%P``Yj  
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public void setSFilePath(String value) ptv4v[gQ  
{ ZY!pw6R1>*  
sFilePath = value; V3W85_*  
} i`aG  
j$|C/E5?  
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public String getSFileName() )Zf}V0!?+  
{ B^(rUR  
return sFileName; dO4#BDn"=  
} LXC`Zq\  
j& o+KV  
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public void setSFileName(String value) ba9<(0`  
{ &E &iaw!  
sFileName = value; 56Y5kxmi  
} Hs}"A,V  
 |~uzQU7  
A]?O&m|  
public int getNSplitter() FFeRE{,  
{ 9H}iX0O  
return nSplitter; =P;;&j3Z  
} C9g~l}=$&  
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public void setNSplitter(int nCount) mjl!Nth:<  
{ ,L{o,qzC  
nSplitter = nCount; h!N&gZ[0  
} R,w54},  
} v~2XGm  
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/* FJ%R3N\  
**Utility.java :iQ^1S`pH  
*/ aho<w+l@  
package NetFox; vx5o k1UY  
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public class Utility { u1|P'>;lF  
l&sO?P[ /  
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public Utility() YNJpQAuSn)  
{ 3Ra\2(bR  
G2+)R^FSC  
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} k *;{n8o?)  
1yaIV+_y/  
//线程睡眠 BQuliX&  
public static void sleep(int nSecond) t6%xit+  
{ ilRm}lU|x  
try{ KYRm Ui#  
Thread.sleep(nSecond); Y\g90
  
} 4}8+)Pd  
catch(Exception e) M`C~6Mf+  
{ y|+~>'^JR  
e.printStackTrace (); >H1|c%w  
} af?\kBm  
} KB,~u*~!  
/,!7jF:  
//日志 Z:o 86~su  
public static void log(String sMsg) ;c m wh<  
{ jRdhLs,M9  
System.err.println(sMsg); A D}}>v  
} '^F|k`$r  
Ss<_K>wk  
3dxnh,]&@  
public static void log(int sMsg) %is,t<G  
{ V
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System.err.println(sMsg); 1Oca@E\Z.  
} CVGOX z  
} S1az3VJI\  
^!o1l-Y^gr  
S QM(8*:X  
/* 17n+4J]  
**TestMethod.java dp UdFuU"  
*/ DUuC3^R  
package NetFox; Y( V3PnH  
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public class TestMethod { T[4[/n>i  
1O]5/Eu  
R
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public TestMethod() p'Y&Z?8  
{ ///xx/weblogic60b2_win.exe Ukh$`q}  
try{ lC /Hib  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %Vw|5yA4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rTP5-4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w;yiX<t<  
fileFetch.start(); M|[@znzR<  
} }rKJeOo^x?  
catch(Exception e){e.printStackTrace ();} _UH/}!nqB  
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]F"(OWW  
} g:uvoMUD  
e>?_)B4  
SG dfhno;  
public static void main(String[] args) B@"SOX  
{ KJ0xp hf  
new TestMethod(); TbKP8zw{  
} g+>=C   
} i14[3bPLk!  
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