http断点续传简单实现（java)

/* F/(z3Kf  
**SiteFileFetch.java ^@a|s Sb  
*/ }@'Zt6+tS  
package NetFox; qyl9#C(a  
import java.io.*; Q&d"uLsx  
import java.net.*; 54geU?p0  
*|F ;An.N^  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean bf2B  
long[] nStartPos; //开始位置 Ce%fz~*b  
long[] nEndPos; //结束位置 <`/22S"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }1)tALA  
long nFileLength; //文件长度 Vr1yj  
boolean bFirst = true; //是否第一次取文件 ?~_[/  
boolean bStop = false; //停止标志 <JyF5  
File tmpFile; //文件下载的临时信息 U<"@@``+N  
DataOutputStream output; //输出到文件的输出流 tXWhq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FO/[7ZH  
public SiteFileFetch(SiteInfoBean bean) throws IOException }kK6"]Tj  
{ 0qPbmLMK  
siteInfoBean = bean; g AZe&"K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v.~uJ.T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -{tB&V~+v  
if(tmpFile.exists ()) \F }s"#  
{ K~I%"r|l  
bFirst = false; R | &+g\{;  
read_nPos(); &~SPDiu.t  
} #,4CeD|(D,  
else g=gWkN <  
{ J_H=GHMp}  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; ;:/<XfZ  
} y_F{C 9KE  
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} *NEA(9  
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public void run() E6f{z9y6  
{ ~$PQ8[=  
//获得文件长度 rpZ^R}B%*v  
//分割文件 '0juZ~>}  
//实例FileSplitterFetch zxV,v*L)  
//启动FileSplitterFetch线程 =mq02C~y  
//等待子线程返回 :*`5|'G}  
try{ !&ly :v!  
if(bFirst) iO 9fg  
{ 8!T6N2O6d  
nFileLength = getFileSize(); 
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if(nFileLength == -1) j1yW{  
{ %e71BZo~^s  
System.err.println("File Length is not known!"); )0Lno|l  
} f-O`Pp FQ  
else if(nFileLength == -2) xXJl Qbs  
{ \"X<\3z2  
System.err.println("File is not access!"); %O!~!'
 
} bi^
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else 'rX!E,59  
{ &f:"p*=a\  
for(int i=0;i<nStartPos.length;i++) S"/M+m+ ]  
{ (eOzntp8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #:Tb(R   
} Wd R~  
for(int i=0;i<nEndPos.length-1;i++) I`~ofq?r  
{ .BWCGb2bH  
nEndPos = nStartPos[i+1]; )sh+cfTCb  
} f*{~N!g  
nEndPos[nEndPos.length-1] = nFileLength; 905%5\Y  
} O!3MXmaO  
} ^o*$OM7x  
:dZq!1~t  
}! jk  
//启动子线程 0&YW#L|J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D]{#!w(d  
for(int i=0;i<nStartPos.length;i++) k4:e0Wd  
{ [+q':T1W-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u+&t"B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6eUM[C.  
nStartPos,nEndPos,i); tqn
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :$>Co\D  
fileSplitterFetch.start(); E*uz|w3S)Y  
} K
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UX?EOrfJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  <|Pw*L$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |Sne\N>%  
nEndPos = " + nFileLength); xXCSaBS~  
// fileSplitterFetch[nPos.length-1].start(); P|>pm]>C  
oi@/H\7j  
vS!%!-F  
//等待子线程结束 :{(` ;fJ  
//int count = 0; GE2^v_  
//是否结束while循环 ?"d25LyN  
boolean breakWhile = false; *0K@^Db-  
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while(!bStop) , ;'y <GA  
{ )} I>"n  
write_nPos(); -v'|#q  
Utility.sleep(500); d)_fI*:f  
breakWhile = true; w?r  
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for(int i=0;i<nStartPos.length;i++) cv .R`)l  
{ 7S +YQ$_  
if(!fileSplitterFetch.bDownOver) lK}W%hzU  
{ {Qe7/ln!  
breakWhile = false; x&ngCB@O  
break; tX<. Ud  
} Ju0W  
} >uu]
K  
if(breakWhile) Dd3GdG@*~  
break; gc ce]QS  
4RLuv?,)~  
=i`#0i2(  
//count++; WOv m%sX  
//if(count>4) NZP>aV-  
// siteStop(); 
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}  QB/H  
9r5<A!1#L  
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System.err.println("文件下载结束！"); *0*1.>Vg  
} LD.^.4{c:  
catch(Exception e){e.printStackTrace ();} %, U
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} {JJq/[j  
|#87|XIJ&~  
Po ,zTz  
//获得文件长度 9XH}/FcP_O  
public long getFileSize() [K*>W[n  
{ D^G5$hi  
int nFileLength = -1; wDL dmrB  
try{ |uT&M`7\{  
URL url = new URL(siteInfoBean.getSSiteURL()); /]_a\x5Ss  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;;*'<\lP.j  
httpConnection.setRequestProperty("User-Agent","NetFox"); `T-lBwH  
=:4vRq
[  
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int responseCode=httpConnection.getResponseCode(); nB8JdM2h{  
if(responseCode>=400) )\!-n]+A  
{ "TLY:V  
processErrorCode(responseCode); 'ot,6@~x>  
return -2; //-2 represent access is error _olhCLIR-  
} cNd;qO0$  
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String sHeader; Nydhal00  

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3 zF"GT  
for(int i=1;;i++) aDae0$lc.S  
{ :epjJ1mW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KBb{Z;%  
//Utility.log(in.readLine()); @S-p[u  
sHeader=httpConnection.getHeaderFieldKey(i); -f4>4@y  
if(sHeader!=null) p5`d@y\hj  
{ ;)SWUXa;{  
if(sHeader.equals("Content-Length")) qMA K"%x  
{ [h3y8O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |, Lp1  
break; J[?7`6\M  
} Gx$rk<;ZW  
} =VctG>ct|  
else ,^>WCG  
break; v4YY6?4  
} ]t23qA@^2  
} o|FY-+  
catch(IOException e){e.printStackTrace ();} --32kuF&(  
catch(Exception e){e.printStackTrace ();} s-z*Lq*  
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Utility.log(nFileLength); ckZZ)lW`*  
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return nFileLength; VgoN=S  
} =,UuQJ,l  
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m  
//保存下载信息（文件指针位置） gA&+<SK(  
private void write_nPos() ]Q%|69H}B  
{ @ZD/y%e  
try{ E@f2hW2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UT^-!L LB]  
output.writeInt(nStartPos.length); TDMyZ!d  
for(int i=0;i<nStartPos.length;i++) w(y#{!%+  
{ :EXH8n&|  
// output.writeLong(nPos); `D#3  
output.writeLong(fileSplitterFetch.nStartPos); Gm
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output.writeLong(fileSplitterFetch.nEndPos); $c WO`\XM  
} x+L G4++  
output.close();
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}
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catch(IOException e){e.printStackTrace ();} )k@+8Yfa1p  
catch(Exception e){e.printStackTrace ();} !A6l\_  
} K]b_JDEk  
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//读取保存的下载信息（文件指针位置） q$;'Fy%oy  
private void read_nPos() L 1fK  
{ f +#  
try{ w84 ]s%y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dwQ*OxFl  
int nCount = input.readInt(); ~+y0UEtq7  
nStartPos = new long[nCount]; aWLeyXsAu  
nEndPos = new long[nCount]; t;Rdrk  
for(int i=0;i<nStartPos.length;i++) L?@TF;
 
{  l*+"0  
nStartPos = input.readLong(); 9}4EW4  
nEndPos = input.readLong(); U2tsHm.O  
} S+i .@N.^  
input.close(); A0NNB%4|/  
} -V'`;zE6  
catch(IOException e){e.printStackTrace ();} 3b_tK^|'  
catch(Exception e){e.printStackTrace ();} [ imC21U  
} 3wS{@'  
^UF]%qqOn  
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private void processErrorCode(int nErrorCode) V/0?0VKG  
{ /mB'Fn6)  
System.err.println("Error Code : " + nErrorCode); =jik33QV<  
} JlR'w]d M,  
a<.7q1F  
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//停止文件下载 `.# l_-U{  
public void siteStop() L`i#yXR  
{ 2p(M`@  
bStop = true; /!o(Y8e>x  
for(int i=0;i<nStartPos.length;i++) #\+TKK  
fileSplitterFetch.splitterStop(); ub"(,k P  
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mx#H+:}&r  
} w8t,?dY
 
} Z\=].[,w4  
//负责部分文件的抓取 (D'Z
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**FileSplitterFetch.java Ag
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*/ K_V44f1f  
package NetFox; J&{qe@
^
 
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import java.io.*; U.oxLbJ`  
import java.net.*; YyX/:1 sg>  
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public class FileSplitterFetch extends Thread { xMsos?5}  
o~ .[sn5l-  
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String sURL; //File URL ]1 #&J(  
long nStartPos; //File Snippet Start Position 3G9YpA_}X  
long nEndPos; //File Snippet End Position -ob_]CKtJ~  
int nThreadID; //Thread's ID 9i)E<.6  
boolean bDownOver = false; //Downing is over 0&U,WA  
boolean bStop = false; //Stop identical /&=E=S6
 
FileAccessI fileAccessI = null; //File Access interface UA[2R1}d  
8T'=lTJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y[gj2vNe4g  
{ UXvk5t1  
this.sURL = sURL; wTFM:N  
this.nStartPos = nStart; |U?5% L  
this.nEndPos = nEnd; ?@9kVB*|  
nThreadID = id; ?H7*?HV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A~Eu_m  
} . m_y5J  
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public void run() P
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{ %R5APMg1  
while(nStartPos < nEndPos && !bStop) @.fuR#  
{ P}o:WI4.cB  
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try{ Vg/{;uLAe  
URL url = new URL(sURL); H,q
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Y1&SEsNX  
httpConnection.setRequestProperty("User-Agent","NetFox"); `G\uTCpk  
String sProperty = "bytes="+nStartPos+"-"; ahkSEE{  
httpConnection.setRequestProperty("RANGE",sProperty); k,M%/AXd  
Utility.log(sProperty); T#^  
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InputStream input = httpConnection.getInputStream(); xA]CtB*o7  
//logResponseHead(httpConnection); qIK"@i[ uq  
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byte[] b = new byte[1024]; Eom|*2vWIC  
int nRead; oD_je~b)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ys:1%D,,_
 
{ R-J\c+C>W  
nStartPos += fileAccessI.write(b,0,nRead); tfj6#{M5  
//if(nThreadID == 1) 7f#
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %\=5,9A\  
} ivC1=+  
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Utility.log("Thread " + nThreadID + " is over!"); -,Cx|Nl  
bDownOver = true; dlN(_6>b  
//nPos = fileAccessI.write (b,0,nRead); {gluK#Qm  
}  7 2ux3D  
catch(Exception e){e.printStackTrace ();} ~WU _u,:  
} Adgh:'h  
} #_y#sDfzh  
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314PcSc  
//打印回应的头信息 8I04Nx  
public void logResponseHead(HttpURLConnection con) mJRvC%  
{ M4pEwD  
for(int i=1;;i++) vGO-a2Z  
{ @Z~lM5n$8  
String header=con.getHeaderFieldKey(i); .MMFN}1O  
if(header!=null) }rsD$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q17c)]<"  
Utility.log(header+" : "+con.getHeaderField(header)); :\L{S  
else bgGd  
break; z:bxnM2\  
} 
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} d*Dq=.F(  
{MU>5\  
5Tluxt71  
public void splitterStop() LEvdPG$)  
{ AZt~ \qf  
bStop = true; &Eg>[gAIlp  
} aM5zYj`pW  
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} g4!zH};n  
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} WY7!Y  
/* 23@e?A=C  
**FileAccess.java ug0[*#|Y  
*//文件访问(定位，写) &\4AvaeA8y  
package NetFox; e@*Gnh<&  
import java.io.*; YUJlQ2e(  
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public class FileAccessI implements Serializable{ l;}D| 6+_W  
lidzs<W-fW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I \zM\^S>]  
RandomAccessFile oSavedFile; }MW*xtGV  
long nPos; %ribxgmd  
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o)Kx:l +f  
public FileAccessI() throws IOException )(TaVHJR  
{ @|(mR-Jj  
this("",0); ^-cj=on=Q  
} 5_ -YF~  
j0^~="p%C  
+'Pl?QyH  
public FileAccessI(String sName,long nPos) throws IOException =HmV0  
{ zg+78  
oSavedFile = new RandomAccessFile(sName,"rw"); ]WR+>)ERb  
this.nPos = nPos; A#M#JI-Y  
oSavedFile.seek(nPos); 8hba3L_Z  
} z]^&^
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)Q9m,/F  
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public synchronized int write(byte[] b,int nStart,int nLen) t%ye:  
{ 'Dv `Gj  
int n = -1; x$d3fsEE  
try{ <:0649ZB  
oSavedFile.write(b,nStart,nLen); \{@s@VBx[  
n = nLen; I-oI,c%+  
} WM5s  
catch(IOException e) ty[bIaQi  
{ u@5vK
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e.printStackTrace (); n3t1'_/TU}  
} `G&W%CHB  
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return n; W&ya_iP~C  
} #Mw|h^Wm  
/2pf*\u  
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} 9YRoWb{y  
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#-dfG
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/* xZW6Hk_  
**SiteInfoBean.java 87P{vf#  
*/ ac"Pn? q  
package NetFox; a5ZU"6Hi  
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public class SiteInfoBean { uSCF;y=1g,  
^IGutZov  
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private String sSiteURL; //Site's URL opxVxjTT#  
private String sFilePath; //Saved File's Path s `fIeP  
private String sFileName; //Saved File's Name O^ZOc0<  
private int nSplitter; //Count of Splited Downloading File _Qg^>}]A1  
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public SiteInfoBean() .}>d[},F  
{//nSplitter的缺省值为5 ss63/  
//default value of nSplitter is 5 5('_7l  
this("","","",5); }[XzM/t  
} #mwV66'
H  
|3{DlZ2S  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) S'M=
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{ Fq/?0B8  
sSiteURL= sURL; LW6&^S?4{  
sFilePath = sPath; E6a$c`H@?  
sFileName = sName; )w];eF0c  
this.nSplitter = nSpiltter; rB|Mp!g%@  
oR (hL4Dc  
+shT}$cb1  
} S!Ue+jW  
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Su`LBz"  
public String getSSiteURL() V&`\ s5Q  
{ _"n1"%Ns  
return sSiteURL; 7NC"}JB&  
} U ^1Xc#Ff  
-5,QrMM<  
:q=u+h_  
public void setSSiteURL(String value) YBn"9w\#  
{ >B(%$jG Z  
sSiteURL = value; 7[5g_D t  
} 9,|{N(N<!  
2%4dA$H#4w  
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public String getSFilePath() owL>w  
{ ,JIjAm*2  
return sFilePath; 4zuM?Dp  
} *(6vO{  
cF!ygz//  
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public void setSFilePath(String value) )W9W8>Cc5_  
{ [tYly`F  
sFilePath = value; ceBu i8a |  
} ZN>oz@jY  
q[p+OpA  
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public String getSFileName() K];`  
{ QA?e2kd  
return sFileName; WLGk  
} (|%YyRaX  
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m<L.H33'  
public void setSFileName(String value) 0'y9HE'e  
{ $g&,$7}O_  
sFileName = value; ?U'c;
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} '>dsROB->  
|uo<<-\jTO  
&}}
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public int getNSplitter() mU.(aLHW  
{ cU <T;1VQ  
return nSplitter; S1oRMd)r  
} ,)%al76E  
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public void setNSplitter(int nCount) d]Y-^&]{]  
{ "e]1|~  
nSplitter = nCount; !Ra.DSL  
} P5 GM s  
} f9v%k'T[  
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/* =xwA'D9]  
**Utility.java H9nVtS
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*/ r[; .1,(  
package NetFox; MZp`  
9_yO6)`  
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public class Utility { N"-</kzV  
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ygt7;};!  
public Utility() T=lir%q  
{  N7%iz+  
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} kmHIU}Z  
ho*44=j  
//线程睡眠 ^7Sk`
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public static void sleep(int nSecond) }yM /z  
{ =.vc={_?  
try{ q2Xm~uN`)  
Thread.sleep(nSecond); k.Tu#7  
} ,S"a ,}8  
catch(Exception e) r$3{1HXc  
{ U)IW6)q  
e.printStackTrace (); ?-"xP'#  
} lwS6"2q  
} .&Uu w  
^`0^|u=  
//日志 >T'=4n['  
public static void log(String sMsg) );4lM%]eb  
{ q ld2<W  
System.err.println(sMsg); Z";~]]$!Y  
} X\X*-.]{  
tI651Wm9  
C>%2'S^.b  
public static void log(int sMsg) bWc3a  
{ }e}J6[wP  
System.err.println(sMsg); Mm7l!  
} &,?bX])  
} }9n{E-bj*  
#qL?;Zh0S  
^[]GsF  
/* :',.I  
**TestMethod.java 88fH!6b  
*/ #$h~QBg  
package NetFox; U`gQ7
 
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5LVhq[}mP  
public class TestMethod { $umh&z/  
;;z4EGr  
yKJKQ9  
public TestMethod() >;@ _TAF  
{ ///xx/weblogic60b2_win.exe W,</  
try{ fhx_v^<X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p4m9@\gn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  3*@ sp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wwnl_9a  
fileFetch.start(); *ea%KE":  
} I@dS/  
catch(Exception e){e.printStackTrace ();} Lf+M +^l  
9NCo0!Fb  
O 0Fw!IQk  
} u&)+~X  
=rBNEd  
 $$E!u}  
public static void main(String[] args) &A=>x  
{ %T:~N<8)  
new TestMethod(); 8l(_{Y5(-  
} ?)=A[  
} ^l\U6$3  
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