http断点续传简单实现（java)

/* )"7hyW5  
**SiteFileFetch.java JL~QE-pvD  
*/ UA4Q9<>~  
package NetFox; }g WSV  
import java.io.*;  &y1' J  
import java.net.*; ?p{xt$<p  
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public class SiteFileFetch extends Thread { %gd=d0vm  
% '>S9Ja3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a!"81*&4#  
long[] nStartPos; //开始位置 66\0JsT?3  
long[] nEndPos; //结束位置 {8M=[4_`l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7e&R6j  
long nFileLength; //文件长度 { .KCK_ d  
boolean bFirst = true; //是否第一次取文件 TQ&%SMCn  
boolean bStop = false; //停止标志 oRM EC7!A0  
File tmpFile; //文件下载的临时信息 od>DSn3T  
DataOutputStream output; //输出到文件的输出流 fFXG;Q8&  
=YX/]g|9K  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bw#z
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public SiteFileFetch(SiteInfoBean bean) throws IOException 4QWDuLu  
{ Kb0OauW  
siteInfoBean = bean; ~CRr)(M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %hU8ycI*h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7BCCQsz<  
if(tmpFile.exists ()) /'1UfjW>  
{ qF6
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bFirst = false; D={|&:`L e  
read_nPos(); y(|6`  
} G
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else <!:,(V>F(C  
{ iV#JJ-OBq  
nStartPos = new long[bean.getNSplitter()]; *IzcW6 [9  
nEndPos = new long[bean.getNSplitter()]; uF>I0J#z?  
} ]I"
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} [!{*)4$6  
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public void run() Kp"mV=RG2T  
{ zMX7 #,  
//获得文件长度 oaI7j=Gp  
//分割文件 
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//实例FileSplitterFetch 
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//启动FileSplitterFetch线程 !U#kUj:4I  
//等待子线程返回 `"[VkQFB/  
try{ } oJ+2OepN  
if(bFirst) wP1dPl_j:0  
{ ~fsAPIQ  
nFileLength = getFileSize(); MxxYMR  
if(nFileLength == -1) r&"}zyL  
{ <
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System.err.println("File Length is not known!"); wd*i~A3+?  
}  ;9c3IK@  
else if(nFileLength == -2) oUZwZ_yKW  
{ 7"=  
System.err.println("File is not access!"); ,oDZ:"
;  
} g'Ft5fQ"o/  
else }E
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{ fl~k')s  
for(int i=0;i<nStartPos.length;i++) n4)G g~PE  
{ #e&j]Q$Eh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N`y!Km  
} \~xsBPX+x  
for(int i=0;i<nEndPos.length-1;i++) wpY%"x#-+=  
{ H's67E/>*  
nEndPos = nStartPos[i+1]; -]5dD VSO  
} ksY^w+>(!  
nEndPos[nEndPos.length-1] = nFileLength; %-]j;'6}cX  
} !'ajpK  
} IGql^,b  
U*/  
a#!Vi93  
//启动子线程 <PW*vo9v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |x{:GW
q  
for(int i=0;i<nStartPos.length;i++) 3z: rUhA  
{ qY
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EBw}/y{Kt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VYf$0oo\4  
nStartPos,nEndPos,i); U_!"&O5lr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?TE#4}p|  
fileSplitterFetch.start(); H1|X0a(j  
} X =S;8=N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gq[}/E0e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2DTH|Yv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yt C{,g>  
nEndPos = " + nFileLength); bEbO){Fe  
// fileSplitterFetch[nPos.length-1].start(); -J!F((jt  
]*juF[r(  
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//等待子线程结束 D8h?s  
//int count = 0; }<FBcc(n  
//是否结束while循环 S7wZCQe  
boolean breakWhile = false; D.qbzJz  
{_3ZKD(\  
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while(!bStop) 30FYq?  
{
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write_nPos(); ,k{{ZP P  
Utility.sleep(500); 2K, 1wqf'  
breakWhile = true; [$.oyjd  
MnKEZ: 2  
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for(int i=0;i<nStartPos.length;i++) ErB6fl  
{ {>QrI4*A  
if(!fileSplitterFetch.bDownOver) /RmLV  
{ fLc<}DF  
breakWhile = false;
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break; JS&l h  
} S?hM  
} G7%Nwe~Y  
if(breakWhile) 0g]ABzTn  
break; p`{<q -  
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//count++; !SiZA"  
//if(count>4) ; {I{X}b  
// siteStop(); rVQ:7\=Z  
} JEY%(UR8  
sF_.9G)S0  
_}jj>+zA`  
System.err.println("文件下载结束！"); X@x: F|/P  
} plfz)x
3  
catch(Exception e){e.printStackTrace ();} q7 Uu 8JXF  
} ?Dd2k%o  
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//获得文件长度 34JkB+#a  
public long getFileSize() c)@M7UK[  
{ 4CX*  
int nFileLength = -1; 5I T'u3V  
try{ BH
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URL url = new URL(siteInfoBean.getSSiteURL()); }qV4]*+{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o>U%3-+T^J  
httpConnection.setRequestProperty("User-Agent","NetFox"); w^R5/#F_r  
=*Wl;PI'  
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int responseCode=httpConnection.getResponseCode();
q#sMew\{  
if(responseCode>=400) UfcM2OmbK  
{ * +A!12s@  
processErrorCode(responseCode); &??(EA3  
return -2; //-2 represent access is error 5Odi\SJ&  
} oH6(Lq'q  
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String sHeader; s)/i_Oe$\  
&lI.N~Ao  
n)`*{uv$  
for(int i=1;;i++) +/Y)s5@<  
{ zb9d{e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h3@mN\=h'  
//Utility.log(in.readLine()); n=rPFpRLF  
sHeader=httpConnection.getHeaderFieldKey(i); *%Gy-5hM  
if(sHeader!=null) /"iYEr%_  
{ )E6m}?H5  
if(sHeader.equals("Content-Length")) MlRgdVX  
{ Mqw&%dz'_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \8Blq5n-O*  
break; LfgR[!  
} dhm;  
} Q.\+ XR_|  
else xu+wi>Y^  
break; / d6mlQS  
} i7 p#%2  
} zac>tXU;  
catch(IOException e){e.printStackTrace ();} i
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catch(Exception e){e.printStackTrace ();} Pq7YJ"Z?:  
L
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Utility.log(nFileLength); XHpoaHyx  
Fzu"&&>0$  
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return nFileLength; JvHJ*E   
} l[\[)X3$  
0dIJgKanGP  
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//保存下载信息（文件指针位置） 1q\U (^  
private void write_nPos() %gw0^^A  
{ NRoi` IIj  
try{ {'d?vm!r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .P,\69g~A  
output.writeInt(nStartPos.length); W4>8
 
for(int i=0;i<nStartPos.length;i++) GVEjB;  
{ I[[rVts  
// output.writeLong(nPos); ,T&B.'cq  
output.writeLong(fileSplitterFetch.nStartPos); ?]3`WJOj  
output.writeLong(fileSplitterFetch.nEndPos); \n<N>j@3  
} gvy%`SSW  
output.close(); I9>1WT<Yy  
} 5[/*UtB  
catch(IOException e){e.printStackTrace ();} &lGp /m:  
catch(Exception e){e.printStackTrace ();} ZB ~D_S  
} eKStt|M'  
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L
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//读取保存的下载信息（文件指针位置） 6x[gg !;85  
private void read_nPos() H3a}`3}U  
{ {Ja#pt  
try{ aNXu"US+Sp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %X[|7D-  
int nCount = input.readInt(); _Dk;U*2  
nStartPos = new long[nCount]; =BX<;vU  
nEndPos = new long[nCount]; xhqIE3gd  
for(int i=0;i<nStartPos.length;i++) 7J>n;8{%?  
{ lZ_i~;u4@v  
nStartPos = input.readLong(); bcj7.rh]'h  
nEndPos = input.readLong(); 9.%{M#j  
} oz[E>%  
input.close(); Keof{>V=CA  
} v5<Ext rV  
catch(IOException e){e.printStackTrace ();} vhhsOga  
catch(Exception e){e.printStackTrace ();} uOW9FAW  
} `+* Mr  
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private void processErrorCode(int nErrorCode) YtIJJH  
{ <ce
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System.err.println("Error Code : " + nErrorCode); iY*Xm,#  
} !T @|9PCp  
:5CwRg  
M>T#MDK\(  
//停止文件下载 %W`pTvF  
public void siteStop() >_&+gn${  
{ ,"}'NH@  
bStop = true; roRZE[ya  
for(int i=0;i<nStartPos.length;i++) }A2@1TTPX  
fileSplitterFetch.splitterStop(); g7d)YUc  
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/- kMzL  
} X8*q[@$  
} L:B&`,E  
//负责部分文件的抓取 fNB*o={r|  
**FileSplitterFetch.java k`TEA?RfQ  
*/ yl3iU:+V  
package NetFox; PU-;Q@< E  
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yY,.GzIjCj  
import java.io.*; Ye1P5+W(  
import java.net.*; [_H9l)  
M(/%w"R  
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public class FileSplitterFetch extends Thread { S!g&&RDx  
<y`yKXzBUV  
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String sURL; //File URL n}?kQOg0/  
long nStartPos; //File Snippet Start Position Ui1K66{  
long nEndPos; //File Snippet End Position 'VF9j\a  
int nThreadID; //Thread's ID \8F$85g  
boolean bDownOver = false; //Downing is over i
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boolean bStop = false; //Stop identical ]`:Fj|>  
FileAccessI fileAccessI = null; //File Access interface O`Z>Oon?  
$wX5`d1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l}<s~
ip  
{ 9prG@  
this.sURL = sURL; F /t;y\)  
this.nStartPos = nStart;  i4Fw+Z  
this.nEndPos = nEnd; ,Xb:f/lB  
nThreadID = id; rU'&o) a^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #UGbSOoCtn  
} oA42?I ^  
, :kCt=4%  
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public void run() TJO|{Lxm  
{ Gzm[4|nO^  
while(nStartPos < nEndPos && !bStop) v8wN2[fC  
{ d5WE^H)E.  
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try{ qLPI^g,  
URL url = new URL(sURL); lkl#
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,cbP yg  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1lx\Pz@ol  
String sProperty = "bytes="+nStartPos+"-"; _ k>j?j-  
httpConnection.setRequestProperty("RANGE",sProperty); /?by4v73P  
Utility.log(sProperty); 1bvL  
9`vse>,-hg  
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InputStream input = httpConnection.getInputStream(); L(X:=) !K0  
//logResponseHead(httpConnection); wV(_=LF  
n}._Nb 5  
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byte[] b = new byte[1024]; V#sANi?mpo  
int nRead; +/UInAM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7G
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{ oTfEX4 t {  
nStartPos += fileAccessI.write(b,0,nRead); %7L'2/Y2x  
//if(nThreadID == 1)  (+Er  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Rhr]ML  
} $Y ]*v)}X  
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1M<'^(t3d  
Utility.log("Thread " + nThreadID + " is over!"); @Yt[%tOF+  
bDownOver = true; Lp{l&-uQ  
//nPos = fileAccessI.write (b,0,nRead); j[=f;&1  
} q 2=^l  
catch(Exception e){e.printStackTrace ();} LWIU7dw  
} ]aaHb  
} Lqz}h-Ei  
;Hm\?n)a  
8BWLi5R[  
//打印回应的头信息 7AtJ6  
public void logResponseHead(HttpURLConnection con) p%,JWZ[  
{
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for(int i=1;;i++) tp0^%!*9  
{ cL`l1:j\}  
String header=con.getHeaderFieldKey(i); \)LY_D:  
if(header!=null) N-vr_4{g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #>!!#e!*  
Utility.log(header+" : "+con.getHeaderField(header)); EV~_-YC   
else WlG/7$  
break; Le_?x  
} n1!u aUC  
} Yz{UP)TC  
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public void splitterStop() AMtFOXx%I  
{ "$m3xO  
bStop = true; {L.0jAwB  
} HW{+THNj  
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} GKm)wOb(*S  
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)%UO@4  
/* V_Y SYG9f  
**FileAccess.java !QC->  
*//文件访问(定位，写) N!H
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package NetFox; 03{e[#
6  
import java.io.*; <tFq6|  
A"w 1GBx  
4UG7{[!+  
public class FileAccessI implements Serializable{ o3%+FWrVTS  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o2Z# 5-  
RandomAccessFile oSavedFile; i) :Q{[D  
long nPos; +}
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6``!DMDt/P  
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public FileAccessI() throws IOException P^.L0T5g  
{ G?YKm1:w  
this("",0); h5B'w  
} z^=9%tLJ  
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3<?(1kSo>>  
public FileAccessI(String sName,long nPos) throws IOException 3O$Q>.0w/  
{ l$.C40v  
oSavedFile = new RandomAccessFile(sName,"rw"); )<jj O  
this.nPos = nPos; Ue~M.LZb  
oSavedFile.seek(nPos); |?{Zx&yUw  
} }0qgvw  
N{oD1%  
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public synchronized int write(byte[] b,int nStart,int nLen) "TG}aS  
{ ar>S_
V
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int n = -1; g6r3V.X'  
try{ / 1E6U6  
oSavedFile.write(b,nStart,nLen); S,qsCnz  
n = nLen; uiO8F*,!&r  
} qI KVu_  
catch(IOException e) 8CwgV  
{ m<TKy_C`  
e.printStackTrace (); x!gu&AA<
*  
} _f2(vWCW;J  
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return n; /R@eOl}D  
} 9?@M Zh  
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} 0FH
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p\F*Y,4  
/* :/d#U:I  
**SiteInfoBean.java #L[Atx  
*/
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package NetFox; t"JfqD E  
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8@Y]dzgjj  
public class SiteInfoBean { jD'\\jAUdm  
2VtiL^;5  
rS8/_'  
private String sSiteURL; //Site's URL H8rDG/>^  
private String sFilePath; //Saved File's Path 8T7[/"hi\  
private String sFileName; //Saved File's Name dk-Y!RfNx  
private int nSplitter; //Count of Splited Downloading File &F)P3=  
oTT/;~I  
-=QA{n  
public SiteInfoBean() oB#KR1 >%7  
{//nSplitter的缺省值为5 ^Jsx^?  
//default value of nSplitter is 5 jt=mK,%  
this("","","",5); r1JKTuuo
 
} ?neXs-'-p  
*)
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x>
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7WKb| /#;  
{ _}{C?611c  
sSiteURL= sURL; .$L'Jt
2X  
sFilePath = sPath; p.gi8%f`  
sFileName = sName; i|y8n7c  
this.nSplitter = nSpiltter; rp+&ax}Wh  
68W&qzw.[r  
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} F@)wi0  
M7BJ$fA0E  
Nz\=M|@(#  
public String getSSiteURL() g
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{ 9}:%CpD^~I  
return sSiteURL; 3g^_Fq'  
} /87?U; |V  
7[.aAGTZ;  
}&bO;o&>  
public void setSSiteURL(String value) Y Dq5%N`  
{ I?EtU/AD  
sSiteURL = value; Pur~Rz\\  
} OZB(4{vnyC  
)zf&`T  
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public String getSFilePath() pa`"f&JO  
{ _.KKh62CN  
return sFilePath; LlrUJ-uC7  
} 2dFC{US'  
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Q+$+
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public void setSFilePath(String value) +pkX$yz  
{ B_aLqB]U  
sFilePath = value; dpxP  
} !Z3iu  
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{D={>0  
public String getSFileName() JS1$l+1  
{ ZQlja  
return sFileName; ,Tvfn`;(  
} Mxc0=I'a  
[]}E- V  
&-dyg+b3  
public void setSFileName(String value) DZ<q)EpC  
{ & w&JE]$ 5  
sFileName = value; o $7:*jU  
} ifHQ2Ug9  
xKi: 2  
q@1b{q#C5  
public int getNSplitter() rF'_YYpr>  
{ AvfSR p  
return nSplitter; +fBbW::R^  
} eG55[V<!  
kc Q~}uFB  
|_xU{Pu  
public void setNSplitter(int nCount) p%/

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{ LZG?M|(6D  
nSplitter = nCount; _lcx?IV  
} ^`XQ>-wWue  
} 3x@t7B  
VEj-%"\  
b1>zGC^|  
/* *~YU0o  
**Utility.java yU<T_&
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*/ __dSEOGoe  
package NetFox; ?Imq4I~)  
!VBl/ aU@  
X,D
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public class Utility { 7jPPN
 
#;4<dDVy  
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public Utility() [C
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{ 2#%@j6  
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'M8wjU  
} xn|M]E1)  
"ld4v+o8l  
//线程睡眠 9ozN$:  
public static void sleep(int nSecond) R~TzZ(Ah]  
{ |h}/#qhR  
try{ lKKg n{R  
Thread.sleep(nSecond); "jS@ug  
} %xv }  
catch(Exception e) %P@V7n  
{ *|n-Hr  
e.printStackTrace (); !:"$1kh1("  
} pbc<326X"  
} T rK-XTev  
wyWe2d  
//日志 /&1FgSARK  
public static void log(String sMsg) k;BXt:jDq  
{ Z'=:Bo{  
System.err.println(sMsg); PggjuPPh  
} [[ {L#  
t,H=;U#  
LGuK@^  
public static void log(int sMsg) m ioNMDG  
{ rnX D(  
System.err.println(sMsg); dA4DW  
} p6P .I8g  
} X^Dklqqy  
nSR7$yS_  
9=RfGx  
/* F%|F-6  
**TestMethod.java PiQsVk  
*/ my|]:(_0d  
package NetFox; DD$YMM  
F{,<6/ayRz  
E^'f'\m  
public class TestMethod { e"g=A=S  
B L^?1x  
5=cS5q@  
public TestMethod() L F<{/c9,  
{ ///xx/weblogic60b2_win.exe vT1StOx<V  
try{ U0X,g(2'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K3g<NC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q)N]*~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~|CWy  
fileFetch.start(); LeP;HP|  
} *m$lAWB5D  
catch(Exception e){e.printStackTrace ();} nLvF^%P8  
I!-"SuBy4J  
4 q-/R  
} yzI`&? P2  
bn*SLWWQ.3  
d-%bRGo/  
public static void main(String[] args) #LU<v  
{ "|k 4<"]  
new TestMethod(); NAg9EaWja{  
} HgY [Q}7s  
} 8_*31Y   
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