http断点续传简单实现（java)

/* .
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**SiteFileFetch.java [ BC%$Sj  
*/ ?%fZvpn-  
package NetFox; 87E3p
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import java.io.*; 9
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import java.net.*; )Ai%wCzw*  
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public class SiteFileFetch extends Thread { X\)KVn`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oHFDg?Z`  
long[] nStartPos; //开始位置 Z.OrHg1  
long[] nEndPos; //结束位置 .p*D[o2 9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -3%)nV  
long nFileLength; //文件长度 <|.! Px86  
boolean bFirst = true; //是否第一次取文件 vrO$8* sy  
boolean bStop = false; //停止标志 ,(kXF:  
File tmpFile; //文件下载的临时信息 {-]HYk  
DataOutputStream output; //输出到文件的输出流 ='||BxB  
A VG`r2T  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NX #d}M^V  
public SiteFileFetch(SiteInfoBean bean) throws IOException }eRG$)'  
{ kvVz-PJy  
siteInfoBean = bean; rQ@
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cb&In<q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zgf||,  
if(tmpFile.exists ()) bRe*(  
{ Saq>o.  
bFirst = false; v?"ee&Y6  
read_nPos(); ?-&D'  
} c5+lm}R?  
else r!gCh`PiK  
{ <>/MKMq!  
nStartPos = new long[bean.getNSplitter()]; v?=VZ~`O(  
nEndPos = new long[bean.getNSplitter()]; P\0%nyOG(%  
} *H<g9<Dn  
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} =WRU<`\  
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{ RX|  
public void run() jY6=+9Jz5  
{ rd~W.b_b  
//获得文件长度 8VGXw;(Y,d  
//分割文件 (mr`?LI}  
//实例FileSplitterFetch @[Qg}'i  
//启动FileSplitterFetch线程 ;4#8#
;  
//等待子线程返回 k3h53QTmC  
try{ &{{f|o=u.  
if(bFirst)
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{ BQ)43Rr>  
nFileLength = getFileSize(); [ +@<T)  
if(nFileLength == -1) 
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{ _ShJ3\,K  
System.err.println("File Length is not known!"); 3t6'5{  
} QHz76i!=>  
else if(nFileLength == -2) d"a7{~l  
{ 7%}}m&A7h  
System.err.println("File is not access!"); uy\+#:44d  
} :2d9ZDyD  
else 5F?g6?j{  
{ 9f[[%80  
for(int i=0;i<nStartPos.length;i++) hRcJ):Wyb  
{ A'R sy6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #e|kA&+8M  
} A0sW 9P6F  
for(int i=0;i<nEndPos.length-1;i++) B y8Tw;aL  
{ KA2B
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nEndPos = nStartPos[i+1]; )yAPYC
 
} I+Cmj]M s0  
nEndPos[nEndPos.length-1] = nFileLength; k~F/Ho+R&  
} Vs(Zs[  
} na; ^/_U@  
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//启动子线程 IKpx~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p5BcDYOw`  
for(int i=0;i<nStartPos.length;i++) /YR$#&N2  
{ /aEQ3x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0~+:~$VrT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tC~itU=V  
nStartPos,nEndPos,i); 0R%58,R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x"T^>Q  
fileSplitterFetch.start(); F+r6/e6a  
} 2p[3Ap  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); = F<`-6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %/C[\wp81  
nEndPos = " + nFileLength); l0_O<  
// fileSplitterFetch[nPos.length-1].start(); ]gk1h=Y~h  
!g:UM R  
7!)%%K.z6  
//等待子线程结束 KrzM]x  
//int count = 0; ( mMz]b5  
//是否结束while循环 :UciFIa  
boolean breakWhile = false; ["/x~\c'N  
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while(!bStop) =LzW#s=O  
{ __npX_4%S  
write_nPos(); #O ]IXo(5z  
Utility.sleep(500); aoX$,~oI5  
breakWhile = true; -6>rR{z  
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for(int i=0;i<nStartPos.length;i++) =0Sa  
{ ~`.%n7  
if(!fileSplitterFetch.bDownOver) r2w7lf66!  
{ [%Xfl7;Wh  
breakWhile = false; 9$i`B>C
~  
break; $ 7!GA9Bn  
} 5}ah
%  
} v$Z1
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if(breakWhile) cxdM!L; `  
break; C3gz)!3  
_=#mmZkq  
| w -W=v  
//count++; H0 t1& :  
//if(count>4) EG6fC4rfC  
// siteStop(); [8#l~ |U  
} !y.7"G*  
3\ed4D  
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System.err.println("文件下载结束！"); 2ra4t]f6  
} hI0l2OE  
catch(Exception e){e.printStackTrace ();} `Fr$q1qae{  
} i=@*F$,  
L4%LE/t|e  
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//获得文件长度 iYkNtqn/  
public long getFileSize() dZZ/(oE>  
{ g-36Q~`9v  
int nFileLength = -1; )-gyDA
 
try{ DK;-2K  
URL url = new URL(siteInfoBean.getSSiteURL()); g=8e.Y*Fr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?Fu.,srt  
httpConnection.setRequestProperty("User-Agent","NetFox"); >{Q2S  
3&f{lsLAC  
8pk">"#s  
int responseCode=httpConnection.getResponseCode(); XlPy(>  
if(responseCode>=400) \&0NH=*^  
{ >{Djx  
processErrorCode(responseCode); ^gImb`<6-  
return -2; //-2 represent access is error Sb.;$Be5g  
} 3@*8\  
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String sHeader; F
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for(int i=1;;i++) b._pG(o1  
{ e6Y0
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]h
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//Utility.log(in.readLine()); tEl_A"^e  
sHeader=httpConnection.getHeaderFieldKey(i); c9V'Zd#  
if(sHeader!=null)
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{ %Ok.XBS)  
if(sHeader.equals("Content-Length")) ND*5pRzvp  
{ %0QYkHdFR`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "PPwJ/L(  
break; 2cL<`  
} nm..$QL  
} Yhfk{CI  
else t"Rn#V\c."  
break; (#~063N,#  
} %"D-1&%zY  
} %-D2I  
catch(IOException e){e.printStackTrace ();} eo!{rs@f  
catch(Exception e){e.printStackTrace ();} umk[\}Ip+P  
#\qES7We6  
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Utility.log(nFileLength); oID,PB*9  
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return nFileLength; 7o3f5"z  
} JXrMtSp\  
v2NzPzzyb  
S"*wP[d.9  
//保存下载信息（文件指针位置） zKo,B/Ke4  
private void write_nPos() 6Y=)12T  
{ i{.!1i:  
try{ [||$1
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output = new DataOutputStream(new FileOutputStream(tmpFile)); raCxHY  
output.writeInt(nStartPos.length); B^Vb=* QRo  
for(int i=0;i<nStartPos.length;i++) y7JJ[:~~  
{ SyI#Q[f'_  
// output.writeLong(nPos); \O56!,k  
output.writeLong(fileSplitterFetch.nStartPos); 9496ayi  
output.writeLong(fileSplitterFetch.nEndPos); 6v-h!1p{u  
} YvonZ  
output.close(); p4=^ UP  
} ] '..G-  
catch(IOException e){e.printStackTrace ();} umY4tNe]$  
catch(Exception e){e.printStackTrace ();} sNWj+T  
} /}Max@.`  
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z,vjY$t:/  
//读取保存的下载信息（文件指针位置） B|tP3<  
private void read_nPos() cOcm9m#  
{ 5=eGiF;0\  
try{ P69S[aqW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7+fFKZFKF  
int nCount = input.readInt(); i9Qx{f88  
nStartPos = new long[nCount]; 3/iGSG`  
nEndPos = new long[nCount]; U.&=b<f(0r  
for(int i=0;i<nStartPos.length;i++) ,Ao8QN  
{ SKGYmleR  
nStartPos = input.readLong(); vq|W&  
nEndPos = input.readLong(); )l^w _;  
} K:mb$YJ&  
input.close(); \%UA6uj  
}  C+_ NG  
catch(IOException e){e.printStackTrace ();} _
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catch(Exception e){e.printStackTrace ();} o`G@Je_}x  
} 1Ypru<.)W  
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private void processErrorCode(int nErrorCode) n<MH\.!tM  
{ Xr-eDUEi  
System.err.println("Error Code : " + nErrorCode); *+5AN306  
} y 2bZo'Z  
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//停止文件下载 )!'SSVaRs  
public void siteStop() @X:P`?("^  
{ bV}43zI.  
bStop = true; vI4St;  
for(int i=0;i<nStartPos.length;i++) t ;(kSg.  
fileSplitterFetch.splitterStop(); 
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} C;_10Rb2ut  
} }{s<!b  
//负责部分文件的抓取 jlItPdCv  
**FileSplitterFetch.java bEbnZ<kz*  
*/ m3,i{  
package NetFox; YoJN.],gf  
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import java.io.*; -3A#a_fu  
import java.net.*; xI$B",?(  
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public class FileSplitterFetch extends Thread { HKV]Rn  
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String sURL; //File URL T0
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long nStartPos; //File Snippet Start Position ]oj 2  
long nEndPos; //File Snippet End Position 0Db#W6*^  
int nThreadID; //Thread's ID *G^QS"%  
boolean bDownOver = false; //Downing is over s/8>(-H#  
boolean bStop = false; //Stop identical Z':}ZXy]  
FileAccessI fileAccessI = null; //File Access interface - 3kg,=HU;  
4Y[tx]<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException np
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{ qlO(z5Ak  
this.sURL = sURL; vn7<>k>dx  
this.nStartPos = nStart; >O?5mfMK  
this.nEndPos = nEnd; ex1bjM7  
nThreadID = id; |\J8:b>}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !>TH#sU$  
} s+l)Q  
#)z_TM07P  
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public void run() zrri&QDF<  
{ 1d,;e:=j  
while(nStartPos < nEndPos && !bStop) I8rtta  
{ "aHA6zTB  
4
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try{ C[z5& x2  
URL url = new URL(sURL); t[|^[%i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q3n(Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Z2HzjE  
String sProperty = "bytes="+nStartPos+"-"; X H,1\J-S  
httpConnection.setRequestProperty("RANGE",sProperty); F<VoPqHq  
Utility.log(sProperty); Q
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*H8(G%a!^  
 $ac VJI?  
InputStream input = httpConnection.getInputStream(); Ou>L|#=!  
//logResponseHead(httpConnection); 0P_q
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byte[] b = new byte[1024]; '#L.w6<B  
int nRead; g)nsP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FMhSHa/B  
{ RX3P%xZ  
nStartPos += fileAccessI.write(b,0,nRead); v!JQ;OX  
//if(nThreadID == 1) BxVo
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0rP`BK|  
} $9)|cO  
'tm%3` F  
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Utility.log("Thread " + nThreadID + " is over!"); S3l$\X;6X  
bDownOver = true; :+: vBrJm  
//nPos = fileAccessI.write (b,0,nRead); eD2u!OKW!  
} D-JG0.@  
catch(Exception e){e.printStackTrace ();} =^#^Mq)  
} b;A(6^V  
} uczOSd  

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//打印回应的头信息 ZUPlMHc  
public void logResponseHead(HttpURLConnection con) pC
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{ /Sy:/
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for(int i=1;;i++) WrP4*6;"  
{ /i.3v45t"  
String header=con.getHeaderFieldKey(i); ~;> psNy  
if(header!=null) 6HeZ<.d
&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m_ >+$uL  
Utility.log(header+" : "+con.getHeaderField(header)); OFH!z{*  
else ?Zu2=<DU  
break; 9O1#%  
} C{^U^>bU  
} f}qR'ognUu  
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public void splitterStop() XqX6UEVR4  
{ 9[31EiT  
bStop = true; 6_1v~#  
} |:Q`9;  
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rRgP/E#_  
} ksb.]P d.  
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/* 8Evon&G59  
**FileAccess.java 4K{<R!2I  
*//文件访问(定位，写) 1HPYW7jk@"  
package NetFox; <e)5$Aj  
import java.io.*; <?h
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(^,4{;YQ5  
;]/>n:[E  
public class FileAccessI implements Serializable{ Tp-<!^o4  
KPW2e2{4@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j6@5"wx  
RandomAccessFile oSavedFile; 0H;,~ WY  
long nPos; fiG/"/u  
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public FileAccessI() throws IOException "'i" @CR  
{ }fzv9$]$  
this("",0); rsSE*(T t  
} )}`3haG  
{6E&\
  
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public FileAccessI(String sName,long nPos) throws IOException @-9u;aL  
{ HH`G/(a  
oSavedFile = new RandomAccessFile(sName,"rw"); (rDB|kc^7  
this.nPos = nPos; h0;PtQb1  
oSavedFile.seek(nPos); 0uZ'j  
} --X1oC52A  
#I]5)XT  
AC'$~4  
public synchronized int write(byte[] b,int nStart,int nLen) !>olD_  
{  B6| g2Tt  
int n = -1; X}
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try{ 4^|;a0Qy]  
oSavedFile.write(b,nStart,nLen); WcE{1&PXx  
n = nLen; L!fiW`>0G  
} C
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catch(IOException e) (+_i^SqK  
{ !4gyrNS  
e.printStackTrace (); UBN^dbP*  
} ~i3/Ec0\  
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return n; e<Pbsj  
} 1a|Z!Vzi  
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} {i}z|'!  
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/* 7x,c)QES`  
**SiteInfoBean.java 67916  
*/ )qi/>GR,  
package NetFox; *&iSW~s  
[5KzawV  
HkH!B.H]  
public class SiteInfoBean { ^Md
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k{fTqKS%h  
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private String sSiteURL; //Site's URL M@
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private String sFilePath; //Saved File's Path !kzC1U  
private String sFileName; //Saved File's Name 86.LkwlqoH  
private int nSplitter; //Count of Splited Downloading File xUp[)B6?:  
D'dE!CAUs  
*TacVp  
public SiteInfoBean() N;)Y+amg^  
{//nSplitter的缺省值为5 mQV
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//default value of nSplitter is 5 GQZLOjsop  
this("","","",5); ?k6PH"M  
} >o\s'i[  
fWr6f`de  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J?Y1G<&  
{ t")+L{  
sSiteURL= sURL; %&D,|Yl6  
sFilePath = sPath; Cpyv@+;D  
sFileName = sName; h}vzZZ2,  
this.nSplitter = nSpiltter; #1>DV@^F  
|sa{!tKJ  
]klP.&I/0  
} kPh;SCr{  
[gZz'q&[)  
V
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public String getSSiteURL() a{?`yO/ 2  
{ f^ q0#+k)  
return sSiteURL; 35 Y#eU2]  
} }Pu|%\  
a!`b`r-4  
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public void setSSiteURL(String value) bu;3Ib3\  
{ $~#N1 
 
sSiteURL = value; 5IK -V)  
} |*~=w J_  
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4v@urW s  
public String getSFilePath() r*-e~  
{ 6
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return sFilePath; mLa0BIP  
} /EJwO3MW  
8 *Fr=+KN  
] D(laqS;"  
public void setSFilePath(String value) n@3(bl
5{  
{ |FF"vRi8a7  
sFilePath = value; =cy;{2S'p  
} iQrT
Ep  
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public String getSFileName() SC'F,!  
{ Ol;}+?[Q  
return sFileName; D$sG1*@s-  
} b4_"dg~gK  
Q?Au.q],  
}]-SAM  
public void setSFileName(String value) Tk9/1C{8  
{ Ri,8rf0u
 
sFileName = value; [+=h[DC  
} v>vU]6l  
Vrz6<c-'B  
4r@dV%:%<  
public int getNSplitter() 'O#,;n  
{ u>~G)lx%  
return nSplitter; 4o:
  
} *{5L*\AZ  
bL=32YS  
[zO
   
public void setNSplitter(int nCount) HJY_l  
{ {J:ZM"GS  
nSplitter = nCount; uUAib<wdPL  
} ~=t,g S  
} 7\'ow|)}v  
F8q&v"  
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/* -j%!p^2j9  
**Utility.java ]jWe']T  
*/ R/H?/  
package NetFox; `r; .  
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public class Utility { gnS0$kCJ:  
&} b'cO  
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public Utility() %ZV a{Nc  
{ :K!@zT=o  
@@U'I^iG  
>\Qyg>Md]  
} .Gq)@{o>  
=rj5 q
  
//线程睡眠 "RuH"~o  
public static void sleep(int nSecond) tS2P|fl  
{ ]xf lfZ  
try{ 7y",%WYSD  
Thread.sleep(nSecond); Qtmsk:qm  
} ~%Y*2i f  
catch(Exception e) _7SOl.5ZE  
{ M) 9Ss  
e.printStackTrace (); 8-cB0F=j_  
} a#X[V5|6Q  
} s[:e '#^  
-\;x>=#B  
//日志 e![|-m%  
public static void log(String sMsg) IX eb6j8  
{ thk33ss:  
System.err.println(sMsg); CtbmX)vE  
} ;9,<&fe
 
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f\oB/  
public static void log(int sMsg) GgH=w`;_  
{ ]Mv.Rul?~  
System.err.println(sMsg); I71kFtvcy*  
}  ]A;zY%>  
} 4ze-N8<[  
=K#D^c~  
d+KLtvB%M  
/* ^s25z=^t  
**TestMethod.java 9:^SnHAa  
*/ Pms"YhyZ7  
package NetFox; [((P,v*  
TY"=8}X1  
ya]CxnKR3  
public class TestMethod { A{Giz&p  
DSyfF&uC  
4{rwNBj(  
public TestMethod() Pj_2y)^?  
{ ///xx/weblogic60b2_win.exe >JVZ@ PV H  
try{ \D BtU7"v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g7k|Ho-W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (3C6'Wt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3O<:eS~  
fileFetch.start(); `[V]xP%V  
}  +Io^U  
catch(Exception e){e.printStackTrace ();} $b;9oST  
oB8u[!  
]}R\[F (_%  
} |`9POl=  
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8>G3KZ3  
public static void main(String[] args) Ch607i=  
{ AW@I,  
new TestMethod(); #_{3W-35*  
} HK>!%t0S  
} w">XI)*z  
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