http断点续传简单实现（java)

/* TUR2|J@n  
**SiteFileFetch.java ^Pc&`1Ap  
*/ )G$0:-J-  
package NetFox; ]1KF3$n0  
import java.io.*; 4--[.j*W  
import java.net.*; n{.SNipU  
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public class SiteFileFetch extends Thread { AkV8}>G?#A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ljO t~@Ea  
long[] nStartPos; //开始位置 3C;nC?]K  
long[] nEndPos; //结束位置 JwmH_nJ(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4kf8Am(  
long nFileLength; //文件长度 \&X*-T[]j  
boolean bFirst = true; //是否第一次取文件 E#+|.0*!s  
boolean bStop = false; //停止标志 +C9l7 q  
File tmpFile; //文件下载的临时信息 G(7WUMjl  
DataOutputStream output; //输出到文件的输出流 9GVv[/NAb  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @EB2I+[  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z;GZ?NOlY  
{ F%q}N,W  
siteInfoBean = bean; *Q2}Qbu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ceak8#|4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |jyoT%SQ  
if(tmpFile.exists ()) sJ)Pj?"\?  
{ g E;o_~  
bFirst = false; Ba]^0Y u  
read_nPos(); [5Pin>]z  
} 2t"&>1  
else ."JtR  
{ %$SO9PY  
nStartPos = new long[bean.getNSplitter()]; [NIaWI,>
 
nEndPos = new long[bean.getNSplitter()]; i;}mIsNBY  
} +`~6Weay  
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} xsdi\ j;n>  
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public void run() VTvNn
  
{ a/H|/CB3  
//获得文件长度 5j$a3nH  
//分割文件 )*n2,n  
//实例FileSplitterFetch ~5b^Gvb?  
//启动FileSplitterFetch线程 Eh&HN-&  
//等待子线程返回 [&a=vE  
try{ YhNO{4D  
if(bFirst) /%w
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{ GbN|!,X1m  
nFileLength = getFileSize(); YB'BAX<lI  
if(nFileLength == -1) .=<
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|  
{ ?mJ&zf|B8  
System.err.println("File Length is not known!"); M[7$cfp-Y~  
} _mn2bc9M  
else if(nFileLength == -2) ORP-@-dap  
{ lr_c  
System.err.println("File is not access!"); P+t`Rw  
} Ov PTgiI!N  
else "s5[w+,R  
{ ,$<="kJk  
for(int i=0;i<nStartPos.length;i++) wW+@3bPl  
{ $z5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eJwHeG  
} *3]_Huw<  
for(int i=0;i<nEndPos.length-1;i++) vX
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{ <mX EX`?  
nEndPos = nStartPos[i+1]; xl4A<  
} M|xs>+r*  
nEndPos[nEndPos.length-1] = nFileLength; 2Bg0 M  
} Y]6kA5  
} eT6T@C
](  
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8rY[Q(]  
//启动子线程 Yb;$z'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C6{\^kG^j2  
for(int i=0;i<nStartPos.length;i++) #cy;((zuB  
{ NANgV~Y&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U/l3C(bc!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sw$$I~21  
nStartPos,nEndPos,i); Ty;P`Uv]r  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ne9S90HsB6  
fileSplitterFetch.start(); GPs
//  
} ;2jH;$HZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A{Dy3tm=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bx8;`QMX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {YigB  
nEndPos = " + nFileLength); K@>($BX]  
// fileSplitterFetch[nPos.length-1].start(); @[. 0,
 
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//等待子线程结束 H4"'&A7$  
//int count = 0; s2*~n_B  
//是否结束while循环 ATscP hk  
boolean breakWhile = false; c1aIZ  
KO3X)D<3  
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while(!bStop) AMf{E  
{ Jwt_d}ns  
write_nPos(); j9^V)\6)  
Utility.sleep(500); 2U.'5uA"L  
breakWhile = true; ;G|#i?JJ  
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for(int i=0;i<nStartPos.length;i++) 5~GH*!h%;  
{ ,zVS}!jRhy  
if(!fileSplitterFetch.bDownOver) "cDMFu  
{ 5e}adHjM  
breakWhile = false; q)PLc{NO  
break; ^LAnR>mz^r  
} &Xh_`*]ox  
} :^H2D=z@  
if(breakWhile) N/6!|F  
break; ^Cy=L]  
s@D/.X  
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//count++; <`'T#e$  
//if(count>4) 5/YGu=
,  
// siteStop(); 5u=>~yK+  
} X([p0W 9V(  
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System.err.println("文件下载结束！"); V 0z`p"  
} r@u8QhD  
catch(Exception e){e.printStackTrace ();} 45A|KaVpg  
} GW,RE\Q:  
<\`qRz0/  
"el}9OitC  
//获得文件长度 F_-}GN%  
public long getFileSize() Xb2.t^ ]f  
{ 7.FD16  
int nFileLength = -1; Tnoy#w}Ve  
try{ 7&&3@96<*#  
URL url = new URL(siteInfoBean.getSSiteURL()); tE WolO[\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AjD?_DPc  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,s`4k?y  
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int responseCode=httpConnection.getResponseCode(); w8}jmpnI  
if(responseCode>=400) )m_q2xV  
{ l/-qVAd!q  
processErrorCode(responseCode); wQX18aF/#d  
return -2; //-2 represent access is error ~CuJ$(9Y  
} R
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Te2C<c  
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String sHeader; (lg~}Jwq  
N$N7aE$  
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for(int i=1;;i++) g&I
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{ ; ,n}>iTE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @Nn'G{8OG  
//Utility.log(in.readLine()); %>-?oor  
sHeader=httpConnection.getHeaderFieldKey(i); (;9j#x  
if(sHeader!=null) >u+%H vzc  
{ (f;.
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if(sHeader.equals("Content-Length")) p^k*[3$0  
{ Zu/w[*;M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L$6W,D  
break; B$ jX%e{:S  
} G@P+M1c  
} 0+T:};]  
else mJZB@m u?  
break; ),J6:O
&  
} `Wd4d2aLG  
} wvRwb  
catch(IOException e){e.printStackTrace ();} M>d^.n  
catch(Exception e){e.printStackTrace ();} 6TDa#k5v  
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Utility.log(nFileLength); |7QSr!{_  
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return nFileLength; >i"WKd=  
} |3mcL'  
*alifdp
 
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//保存下载信息（文件指针位置） {q! :t0X.Y  
private void write_nPos() dU-nE5  
{ zX]l$Q+  
try{ 1`GW>ZKv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QXW>}GdKZ  
output.writeInt(nStartPos.length); Ca-.&$f  
for(int i=0;i<nStartPos.length;i++) 7(d#zu6n  
{ @r=,: 'Mt  
// output.writeLong(nPos); G > t  
output.writeLong(fileSplitterFetch.nStartPos); 1zgM
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output.writeLong(fileSplitterFetch.nEndPos); ;3XOk+  
} a4n5i.;  
output.close(); Ibg~.>.u{  
} '61>.u:2  
catch(IOException e){e.printStackTrace ();} "U/yq
 
catch(Exception e){e.printStackTrace ();} Nw{Cu+AwG  
} jq%}=-%KE  
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//读取保存的下载信息（文件指针位置） ]k8f1F  
private void read_nPos() f@2F!  
{ 3$S~!fh  
try{ Xl:.`{5L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a(kY,<}  
int nCount = input.readInt(); v 6s]X*l?  
nStartPos = new long[nCount]; Rg^ps  
nEndPos = new long[nCount]; !%[fi[p  
for(int i=0;i<nStartPos.length;i++) hj}PL  
{ Nt\0) &b  
nStartPos = input.readLong(); ^*w}+tB  
nEndPos = input.readLong(); "T*1C=  
} .>Qa3,v5  
input.close(); 3m$ck$  
} axOEL:-|Bu  
catch(IOException e){e.printStackTrace ();} Y<
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catch(Exception e){e.printStackTrace ();} M:dH>  
} !f]kTs]j~  
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private void processErrorCode(int nErrorCode) `"o{MaFA  
{ virt[5w  
System.err.println("Error Code : " + nErrorCode); yy+:x/(N[  
} &*745,e  
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//停止文件下载 F]fXS-@ c  
public void siteStop() |*DkriYY  
{ K>C@oE[W  
bStop = true; 10)RLh|+  
for(int i=0;i<nStartPos.length;i++) `:C2Cj  
fileSplitterFetch.splitterStop(); GaV}@Q  
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} =dsEt\ j  
} _zJ /z  
//负责部分文件的抓取 _90<*{bt.  
**FileSplitterFetch.java i]OEhB Y  
*/ $E.Fgy:G  
package NetFox; mi.,Z`]o  
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3 qJ00A
  
import java.io.*; xkU8(=  
import java.net.*; u:Ye`]~o  
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public class FileSplitterFetch extends Thread { /]U;7)  
(G/(w%#7_  
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String sURL; //File URL z~==7:Os  
long nStartPos; //File Snippet Start Position D/JSIDd  
long nEndPos; //File Snippet End Position q#SEtyJL  
int nThreadID; //Thread's ID 3=^)=yOd  
boolean bDownOver = false; //Downing is over C"$~w3A k  
boolean bStop = false; //Stop identical *l;S"}b*,_  
FileAccessI fileAccessI = null; //File Access interface JU.!<  
$7W5smW/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jD%|@ux  
{ \<\H1;=.@'  
this.sURL = sURL; &]GR
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this.nStartPos = nStart; *X{7m]5  
this.nEndPos = nEnd; IsShAi  
nThreadID = id; TZ `Ypi7r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1uppE|  
} i]J.WFu  
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public void run() J@"UFL'^  
{ k5J18S  
while(nStartPos < nEndPos && !bStop) dpK-  
{ G.^)5!By  
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try{ \#WWJh"W  
URL url = new URL(sURL); jvAjnh#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;]b4O4C\  
httpConnection.setRequestProperty("User-Agent","NetFox"); TLp2a<Iy  
String sProperty = "bytes="+nStartPos+"-"; a
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httpConnection.setRequestProperty("RANGE",sProperty); O!^ >YvOh  
Utility.log(sProperty); KeRC8mYp  
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#"lb9._M  
InputStream input = httpConnection.getInputStream(); /!^,+  
//logResponseHead(httpConnection); *^Ges;5$"  
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byte[] b = new byte[1024]; UCK;?]  
int nRead; 0[M2LF!m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |Olz h63k:  
{ `/'p1?Z"  
nStartPos += fileAccessI.write(b,0,nRead); 1G.?Y3DC<  
//if(nThreadID == 1) Z^z{, u;!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2~l7WW+lx,  
} F_9 4k  
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Utility.log("Thread " + nThreadID + " is over!"); #ACT&J  
bDownOver = true; sW'_K.z  
//nPos = fileAccessI.write (b,0,nRead); [7d(PEQL`  
} *9uNM@7&0  
catch(Exception e){e.printStackTrace ();} ^_g%c&H  
} !LM`2|3$  
} M. % p'^5  
\Vroz=IT:  
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//打印回应的头信息 WcoA)we  
public void logResponseHead(HttpURLConnection con) M_Q`9  
{ ZSW@,
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for(int i=1;;i++) iw=e"6V  
{ sNcU>qjj6  
String header=con.getHeaderFieldKey(i); p JT)X8K"  
if(header!=null) /]'&cD 1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :r ~iFP*  
Utility.log(header+" : "+con.getHeaderField(header)); J(@" 7RX  
else 8h }a:/  
break; *~shvtq  
} U#
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} 2oV6#!{Z  
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public void splitterStop() VFx[{Hy  
{ J]XLWAM  
bStop = true; t!SxJB e  
} WeaT42*Q{  
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} az:}RE3o  
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/* yo->mD  
**FileAccess.java DbLo{mFEIj  
*//文件访问(定位，写) bGL}nPo  
package NetFox; J`)/\9'&&  
import java.io.*; M!5=3>Z  
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public class FileAccessI implements Serializable{ D (8Z90  
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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 >6jal?4u-  
RandomAccessFile oSavedFile; l0`bseN<  
long nPos; @vyEN.K%mm  
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public FileAccessI() throws IOException <mlN\BcX;  
{ w(aj'i  
this("",0); \%Y`>x.  
} H`fJ<So?  
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public FileAccessI(String sName,long nPos) throws IOException ?!U.o1  
{ ym%` l!
 
oSavedFile = new RandomAccessFile(sName,"rw"); E;s_=j1f  
this.nPos = nPos; <uB)u>3   
oSavedFile.seek(nPos); e ar:`11z  
} @@U  
4)D~S4{E5  
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public synchronized int write(byte[] b,int nStart,int nLen)  B>:U  
{ YcX"Z~O6j=  
int n = -1; Z\`SDC  
try{ xtD(tiqh.;  
oSavedFile.write(b,nStart,nLen); HM0&%  
n = nLen; Q"u2<  
} !;(Wm6~*ad  
catch(IOException e) G^nG^HTo5  
{ \1joW#  
e.printStackTrace (); FCEmg0qdjD  
} -.? @f tY  
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return n; #GlFm?/6K/  
} dR.?Kv(,E  
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} Xwo+iZ(a  
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/* !Whx^B:  
**SiteInfoBean.java zn^7#$fC  
*/ #z&R9$  
package NetFox; +g7]ga  
<";1[A%7<  
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public class SiteInfoBean { 1G12FV>M  
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private String sSiteURL; //Site's URL '@+q_v@Jl  
private String sFilePath; //Saved File's Path ^_\m@
 
private String sFileName; //Saved File's Name v&;JVai  
private int nSplitter; //Count of Splited Downloading File u(8{5"
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;}f {o^]'  
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public SiteInfoBean() QeFt WjlqC  
{//nSplitter的缺省值为5 iOhX\@&  
//default value of nSplitter is 5 o:ow"cOEf  
this("","","",5); |pBFmm*  
} f?=0Wzb  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P3W3+pwq  
{ '[8w8,v(  
sSiteURL= sURL; bXOM=T  
sFilePath = sPath; J5jI/
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sFileName = sName; Tf!6N<dRXR  
this.nSplitter = nSpiltter; cE`qfz  
&E0^Jz  
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} Ws0)B8y,|  
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public String getSSiteURL() XSN=0N!GB  
{ QA^FP8!j  
return sSiteURL; >)NS U  
} zmD7]?|  
%wru)  
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public void setSSiteURL(String value) KwaxNb5  
{ o-&0_Z
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sSiteURL = value; /CyFe<t  
} qhTVsZ:{C  
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public String getSFilePath() ep},~tPZn  
{ ?-2s}IJO  
return sFilePath; M~
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} X-" +nThMn  
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+Tx_q1/f5X  
public void setSFilePath(String value) P{%Urv{U  
{ 9dAtQwGR"6  
sFilePath = value; -~JYfj@  
} -e0[$v  
6!itr"  
FAc^[~E  
public String getSFileName() `s+kYWg'Z  
{ :Sd`4
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return sFileName; T4}Wg=UKg  
} | X#!5u  
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]n"RPktx  
public void setSFileName(String value) kmu`sk"  
{ P{n*X  
sFileName = value; j+ L:Ao  
} tEo-Mj5:  
z>y#^f)r  
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public int getNSplitter() za 7+xF  
{ YIgHLM(  
return nSplitter; E>5p7=Or;"  
} Bvjsl  
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public void setNSplitter(int nCount) ?fC9)s  
{ z'1%%.r;FM  
nSplitter = nCount; UA~ 4O Q]  
} w8UUeF  
} -z-yk~F  
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/5L\:eX%  
/* &!WRa@x0I  
**Utility.java ]&D=*:c  
*/ GRofOJ  
package NetFox; ='qVwM['  
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public class Utility { $X/'BCb  
5|pF*8*  
EH M59s|B  
public Utility() QZ;DZMP  
{ > cWE@P  
/2/aMF(J  
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} 6H  U*,  
~Sm6{L  
//线程睡眠 ^^B_z|;Aa  
public static void sleep(int nSecond) \.H9e/vU`  
{ ,tyPZR_  
try{ >D~8iuy]8.  
Thread.sleep(nSecond); 4~FRE)8  
} v_/<f&r  
catch(Exception e) ly6zz|c5  
{ .{`C>/"}  
e.printStackTrace (); oZ tCx  
} cRbA+0m>  
} &zEBfr  
k[a<KbS  
//日志 :p]e4|R  
public static void log(String sMsg) ]plp.f#av  
{ +s8R]3NJ_H  
System.err.println(sMsg); 9"gu>  
} w4TQ4 Y  
cYC^;,C &|  
eQ8t.~5;-  
public static void log(int sMsg) SN L-6]j  
{ "Z,T%]  
System.err.println(sMsg); &V(6N%A^U  
} {!qnHv\S  
} 6G"UXNa,  
Mz2TwU_  
J+ S]Qoz  
/* p?ccBq
  
**TestMethod.java 2/s42 FoG  
*/ ~XuV:K3  
package NetFox; `<>QKpAn  
|D/a}Av>B  
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public class TestMethod { m26YAcip}  
~v pIy-  
YOGj__:  
public TestMethod() t? 6 et1~  
{ ///xx/weblogic60b2_win.exe 5BXku=M  
try{ Mkk.8AjC|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0!lWxS0#=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >JS^yVk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jED.0,+K!  
fileFetch.start(); ,z/aT6M?H  
} (,QWK08  
catch(Exception e){e.printStackTrace ();} wDW%v@  
^w~B]*A:"  
|%XTy7^a  
} R3|4|JlGR  
+#BOWz  
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public static void main(String[] args) |H_WY#  
{ X`Q+,tx$  
new TestMethod(); /R=MX>JA;  
} q: FhuOP  
} wv{ Qx^  
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