http断点续传简单实现（java)

/* T }8r;<P6  
**SiteFileFetch.java .R<s<]  
*/ x~3
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package NetFox; %8z+R m,Ot  
import java.io.*; 37ri b  
import java.net.*; 8V53+]c$Y  
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public class SiteFileFetch extends Thread { h!J
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SiteInfoBean siteInfoBean = null; //文件信息Bean #nMP(ShK  
long[] nStartPos; //开始位置 hg86#jq%  
long[] nEndPos; //结束位置 |Ls&~'ik  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8WLh]MD`  
long nFileLength; //文件长度 ^<5^9]x  
boolean bFirst = true; //是否第一次取文件 \fQgiX  
boolean bStop = false; //停止标志 1W6n[
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File tmpFile; //文件下载的临时信息 r*
 
DataOutputStream output; //输出到文件的输出流 sDh6 Uk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZQ-z2s9U  
public SiteFileFetch(SiteInfoBean bean) throws IOException HzO0K=Z=R0  
{ q4IjCu+  
siteInfoBean = bean; )}zA,FOA*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Qbe{/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j:vD9sdQ  
if(tmpFile.exists ()) WLj_Zo*^x  
{ .+yJh  
bFirst = false; LeRh(a`=$  
read_nPos(); JOE{&^j  
} &caO*R<#J}  
else \:f}X
?:  
{ 5]2!Bb6>  
nStartPos = new long[bean.getNSplitter()]; n(F<  
nEndPos = new long[bean.getNSplitter()]; ve_4@J)  
} ht[TMdV  
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} V.OoZGE>]  
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public void run() dT0z^SG  
{ Zqe[2()  
//获得文件长度 A_4\$NZ^  
//分割文件 *b7 ^s,?  
//实例FileSplitterFetch oVj A$|  
//启动FileSplitterFetch线程 tIp\MXkTQ&  
//等待子线程返回 Lu$:,^ C  
try{ {t IoC;Y  
if(bFirst) n6-!@RYr  
{ fPuQ,J2=  
nFileLength = getFileSize(); oqm{<g?2  
if(nFileLength == -1) ":#A>L? l  
{ \Jj'60L^  
System.err.println("File Length is not known!"); bKTwG@{/k  
} )8A=yrTIT  
else if(nFileLength == -2) A<G ;  
{ V1+o3g{}  
System.err.println("File is not access!"); EXM/>PG  
} eVbh$cIrZ  
else :-jP8X  
{ mm9S#Ya  
for(int i=0;i<nStartPos.length;i++)  cB{;Nh6"  
{ o@V/37!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @5nkI$>3z  
} 7$!Bq#  
for(int i=0;i<nEndPos.length-1;i++) uS+b* :  
{ fqp7a1qQl  
nEndPos = nStartPos[i+1]; FK,r<+h  
} 0BU:(o
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nEndPos[nEndPos.length-1] = nFileLength; h"%,eW|^  
} YUE1 '}  
} hE3jb.s(>  
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//启动子线程 w})&[d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W SeRV?+T  
for(int i=0;i<nStartPos.length;i++) $F'~^2  
{ ok=E/77`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nd9-3W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IU"!oM^  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FU3IK3}  
fileSplitterFetch.start(); 
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} qb/!;U_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y&:\s8C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }jy7,+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Iw-6Z+ 94  
nEndPos = " + nFileLength); %4g4 C#  
// fileSplitterFetch[nPos.length-1].start(); hD~/6bx  
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//等待子线程结束 E52:c]<'m  
//int count = 0; ZCq\Zk1O&  
//是否结束while循环 mgl' d  
boolean breakWhile = false; 'k) P(H  
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while(!bStop) 4w  
{ SodW5v a  
write_nPos(); ToCfLJ?{  
Utility.sleep(500); YH6K-}  
breakWhile = true; m3ZOq B-  
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for(int i=0;i<nStartPos.length;i++) NomK(%8m$  
{ ,wy:RVv@e  
if(!fileSplitterFetch.bDownOver) 2Uw}'J_N  
{ { l~T~3/i  
breakWhile = false; pc(9(. |  
break; FP cvkXQD  
} hYQ%|CBXBR  
} ).6/ii9gt  
if(breakWhile) l@2`f#y1~<  
break; lJpv
 
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//count++; P>cJ~FM  
//if(count>4) Lgw@y!Llij  
// siteStop(); kxiyF$ 9  
} (W6\%H2u  
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System.err.println("文件下载结束！"); h!3Z%M  
} S`PSFetC  
catch(Exception e){e.printStackTrace ();} Nr7.BDA  
} l`G:@}P>G  
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//获得文件长度 T{kwy3  
public long getFileSize() %Y[/Ucdm  
{ )bJ6{&  
int nFileLength = -1; 0md{e`'q:  
try{ `o-<,  
URL url = new URL(siteInfoBean.getSSiteURL()); .jU0Hu{F4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !,WRXE&j  
httpConnection.setRequestProperty("User-Agent","NetFox"); n_gB#L$  
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int responseCode=httpConnection.getResponseCode(); ^E,UcK;  
if(responseCode>=400) aj~@r3E;  
{ {?_)m/
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processErrorCode(responseCode); S`-IQ,*}  
return -2; //-2 represent access is error ?-p aM5Q+  
} "K=)J'/n  
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String sHeader; 6:X\vw  
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for(int i=1;;i++) S;kc{?  
{ h(K4AiGE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %5w)}|fw  
//Utility.log(in.readLine()); y
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sHeader=httpConnection.getHeaderFieldKey(i); 1Vvx@1  
if(sHeader!=null) M& L0n%,y5  
{ MH(g<4>*  
if(sHeader.equals("Content-Length")) Y&%0 eI!  
{ UYLI>XSd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dXN&<Q,  
break; ?XrTZ{5'  
} {x$#5PW  
} 6XqO'G  
else JH,+F  
break; T0C'$1T  
} ,o6: V]a  
} 7hE=+V8  
catch(IOException e){e.printStackTrace ();} Jk{2!uP  
catch(Exception e){e.printStackTrace ();} 5Uz(Bi  
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Utility.log(nFileLength); LLN^^>5|l  
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return nFileLength; G*V 7*KC  
} NsK>UJ'  
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//保存下载信息（文件指针位置） !9Ni[8&Fg0  
private void write_nPos() @1X1E 2:  
{ [#H8Mb+7  
try{ D]y.!D{l2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9a,CiH%@  
output.writeInt(nStartPos.length); VUhu"h@w%  
for(int i=0;i<nStartPos.length;i++) 2sq<"TlQXI  
{ C*zdHzMj  
// output.writeLong(nPos); s_Gp +-  
output.writeLong(fileSplitterFetch.nStartPos); 6YbSzx`?k  
output.writeLong(fileSplitterFetch.nEndPos); I>|?B(F  
} j(N9%/4u  
output.close(); 81C?U5  
} ]C^*C|  
catch(IOException e){e.printStackTrace ();} yIP IA%dJ  
catch(Exception e){e.printStackTrace ();} 6FAP *V;  
} 4\iQ%fb  
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//读取保存的下载信息（文件指针位置） eZo%q,L  
private void read_nPos() v-@@>?W-  
{ A
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try{ }
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .$;GVJ-:5  
int nCount = input.readInt(); 1Zzw|@#>o  
nStartPos = new long[nCount]; S6I8zk)Z4  
nEndPos = new long[nCount]; 5}VP-04vh  
for(int i=0;i<nStartPos.length;i++) |M&/(0  
{ (
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nStartPos = input.readLong(); kdq55zTc<6  
nEndPos = input.readLong(); 9wzYDKN}  
} j/\XeG>  
input.close(); =<icHt6s  
} S{06bLXU"  
catch(IOException e){e.printStackTrace ();} 1:8: yFV  
catch(Exception e){e.printStackTrace ();} =XB)sC%  
} ce\-oT  
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private void processErrorCode(int nErrorCode) vhW'2<(  
{ ?*0kQo'  
System.err.println("Error Code : " + nErrorCode); 7y3; F7V  
} *!kg@ _0K  
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//停止文件下载 I._=q  
public void siteStop() i)ctrdP-  
{ =r2d{  
bStop = true; H'.d'OE:I  
for(int i=0;i<nStartPos.length;i++) -mF9S
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fileSplitterFetch.splitterStop(); mBF?+/l  
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} #,Y}  
} r`@Dgo}  
//负责部分文件的抓取 IYFA>*Es  
**FileSplitterFetch.java FdD'H
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*/ @2<J_Ja  
package NetFox; ~Q0}>m,S  
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import java.io.*; P:+:Cm<  
import java.net.*; Sy
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public class FileSplitterFetch extends Thread { "Q( 8FF  
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String sURL; //File URL 9azPUf) C  
long nStartPos; //File Snippet Start Position K;~dZ  
long nEndPos; //File Snippet End Position &2DW  
int nThreadID; //Thread's ID 3ba"[C|  
boolean bDownOver = false; //Downing is over l`k3!EZDS  
boolean bStop = false; //Stop identical D{mu2'q  
FileAccessI fileAccessI = null; //File Access interface +
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }z[se)s  
{ Ic*Q(X  
this.sURL = sURL; u|C9[(  
this.nStartPos = nStart; f]EHDcC3X  
this.nEndPos = nEnd; sQkP@Y  
nThreadID = id; !Kis,e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DbDpdC;  
} /i<g>*82  
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public void run() `'/8ifKz  
{ Z-p_hNb  
while(nStartPos < nEndPos && !bStop) \Z$*8z=  
{ n~h%K7 c  
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try{ j'W)Nyw$[  
URL url = new URL(sURL); _>*"6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KLk37IY2\  
httpConnection.setRequestProperty("User-Agent","NetFox"); JGtd
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String sProperty = "bytes="+nStartPos+"-"; lxeolDl  
httpConnection.setRequestProperty("RANGE",sProperty); t?s1@
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Utility.log(sProperty); A[oRi}=  
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InputStream input = httpConnection.getInputStream(); >y?$aJ8ZV  
//logResponseHead(httpConnection); <K43f#%  
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byte[] b = new byte[1024]; 8WvT0q>]  
int nRead; @!S5FOXipZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |qBo*OcO  
{ ~9{.!7KPc  
nStartPos += fileAccessI.write(b,0,nRead); Vrnx#j-U  
//if(nThreadID == 1) (efH>oY[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TCVJ[LbJ  
} Ne=D$o  
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Utility.log("Thread " + nThreadID + " is over!"); j/sZ:Q  
bDownOver = true; vm(% u!_P  
//nPos = fileAccessI.write (b,0,nRead); Mqq7;w@(J  
} OlP#|x*  
catch(Exception e){e.printStackTrace ();} }} IvZG&  
} NTV0DkX  
} %bAv.'C  
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//打印回应的头信息 `18G 5R  
public void logResponseHead(HttpURLConnection con) /h_BF\VBs  
{ _^KD&t%!+y  
for(int i=1;;i++) }{[F+|\>,e  
{ 
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String header=con.getHeaderFieldKey(i); 5n_<)Ycj  
if(header!=null) BUtXHD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L"IdD5`7T  
Utility.log(header+" : "+con.getHeaderField(header)); rn(
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else [u<1DR  
break; ?xy~N?N  
} Q@2Smtu~c  
} x{=ty*E  
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public void splitterStop() k'm!|  
{ HxkhlNB  
bStop = true; spJB6n(  
} !4|7U\;  
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} .6r&<*  
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/* =|H/[",gg  
**FileAccess.java $} ~:x_[  
*//文件访问(定位，写) eOS#@6U=u  
package NetFox; N/Z<v* i"  
import java.io.*; g4Tc (k#  
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public class FileAccessI implements Serializable{ 0
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w* v%S  
RandomAccessFile oSavedFile; m#Rll[  
long nPos; O4 [[9  
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public FileAccessI() throws IOException cBU>/ zIp  
{ [N{Rd[{QTL  
this("",0); z55P~p  
} H1+
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public FileAccessI(String sName,long nPos) throws IOException hMdsR,Iq  
{ Qd$d*mwg:  
oSavedFile = new RandomAccessFile(sName,"rw"); PX+$Us  
this.nPos = nPos; z1s9[5  
oSavedFile.seek(nPos); x#U?~6.6  
} Tf` ~=fg%  
o[_{\  
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public synchronized int write(byte[] b,int nStart,int nLen) UL(#B TK  
{ \!`*F:7]-  
int n = -1; gJ:Z7b  
try{ jytfGE:  
oSavedFile.write(b,nStart,nLen); ZfS-W&6Z  
n = nLen; iGM-#{5  
} e:&5Cvx  
catch(IOException e) {=pf#E=  
{ {~VgXkjsC  
e.printStackTrace (); >!?u8^C  
} _.zW[;84b  
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return n; 7h,SX]4Q  
} yo3'\I  
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} ob-y {x,R  
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/* Za5*HCo  
**SiteInfoBean.java a~WtW]  
*/ c1Xt$[_  
package NetFox; ! p458~|  
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public class SiteInfoBean { MX]<tR`  
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}"E?#&^  
private String sSiteURL; //Site's URL !Hxx6/  
private String sFilePath; //Saved File's Path /(5SJ(a  
private String sFileName; //Saved File's Name ?tSFM:9PU  
private int nSplitter; //Count of Splited Downloading File  5'Y @c  
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@ITJ}e4  
public SiteInfoBean() vA*!82  
{//nSplitter的缺省值为5 fU8 &fo%ER  
//default value of nSplitter is 5 hVd% jU:  
this("","","",5); gM '_1zs U  
} [YLaRr  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \GEFhM4)  
{ ULNU'6  
sSiteURL= sURL; ^/U-(4O05*  
sFilePath = sPath; UzWf_
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sFileName = sName; Tm 6<^5t  
this.nSplitter = nSpiltter; S)T~vK(n  
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} bODCC5
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public String getSSiteURL() =]K;"  
{ @Xts}(L  
return sSiteURL; P{h;2b{  
} Mpzt9*7R  
}.>( [\q  
@2nar<  
public void setSSiteURL(String value) xrs?"]M[  
{ :<r.n "  
sSiteURL = value; IQAV`~_G  
} ;`p+Vs8C  
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public String getSFilePath() @FKm
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{ 9nN$%(EO5;  
return sFilePath; _0Qp[l-  
} 2v\,sHw+-  
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public void setSFilePath(String value) P-o/ax  
{ U-&dn%Sq  
sFilePath = value; |3<tDq@+  
} W<_9*{|E;  
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public String getSFileName() >x]b"@Hkw  
{ CoO..  
return sFileName; gi\2bzWkbX  
} S~X&^JvT  
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public void setSFileName(String value) ,@!io  
{ {]BP
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sFileName = value; gG*]|>M JI  
} f3El9[  
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public int getNSplitter() 'Z5l'Ac  
{ 7)SG#|v[$  
return nSplitter; ]/g&y
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} wFI2(cQ  
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public void setNSplitter(int nCount) 5#|D1A  
{ X$Eg(^La  
nSplitter = nCount; cLhHGwX=x  
} *'[8FZ|dQ  
} @-ps[b`z  
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/* G%5bQ|O  
**Utility.java $23*:)&J4  
*/ pn"TFapJA  
package NetFox; Sp/t[\,'  
r{2V`h1/|  
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public class Utility { 9n
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public Utility() J,q6  
{ Uao8#<CkvJ  
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} 8G3CQ]G  
u*}[fQ`aF  
//线程睡眠 tV.qdy/]}  
public static void sleep(int nSecond) ]rC2jB\,M  
{ <KY \sb9  
try{ 5\!t!FL_  
Thread.sleep(nSecond); n1!hfu7@s  
} NSs"I]  
catch(Exception e) D/U=zDpiB  
{ q~:H>;:G-  
e.printStackTrace (); nUb0R~wr$G  
} w1;:B%!H  
} *~Y$8!ad  
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//日志 =f~8"j  
public static void log(String sMsg) -nK\+bTL}  
{ lQ&"p+n  
System.err.println(sMsg); G42J  
} B8Vhl:p  
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public static void log(int sMsg) +>bm~6  
{ Y["aw&;#O\  
System.err.println(sMsg); 2bv/-^  
} R;d)I^@  
} 0+3_CS++r  
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5z/*/F=X  
/*
,i]X^z5!  
**TestMethod.java I}^Q u0ub  
*/ r,cz yE/  
package NetFox; `|
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public class TestMethod { YzA6*2  
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public TestMethod() RKi11z  
{ ///xx/weblogic60b2_win.exe DjLSl,Z  
try{ xVnk]:c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C\`*_t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pZxuV(QP`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bT>1S2s  
fileFetch.start(); 2|a5xTzH  
} #3~hF)u&/  
catch(Exception e){e.printStackTrace ();} Yq~$pVgf  
Q
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} {)`tN&\  
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@LyCP4  
public static void main(String[] args) (_0r'{`  
{ 8el\M/u{  
new TestMethod(); uD=FTx  
} ztEM>xsk  
} _8 C:Md`  
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