http断点续传简单实现（java)

/* HCYy9  
**SiteFileFetch.java MCIuP`sC|  
*/ 3RD+;^}q3  
package NetFox; {A%&D^o)  
import java.io.*; u@+^lRGFh  
import java.net.*; hOs~/bM  
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public class SiteFileFetch extends Thread { 74(bo\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Dr(;A>?qG  
long[] nStartPos; //开始位置 Ra^c5hP:.E  
long[] nEndPos; //结束位置 ycEp,V;[Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :9q|
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long nFileLength; //文件长度 AT2D+Hi=E  
boolean bFirst = true; //是否第一次取文件 xa !/.  
boolean bStop = false; //停止标志 B[f:T%  
File tmpFile; //文件下载的临时信息 9\E];~"iP  
DataOutputStream output; //输出到文件的输出流 *$JS}Pax  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;Yg/y  
public SiteFileFetch(SiteInfoBean bean) throws IOException p^p1{%=  
{ hu}uc&N)iE  
siteInfoBean = bean; 
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ly1t'{"7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bI
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if(tmpFile.exists ()) M?n}{0E4  
{ mM+^v[=  
bFirst = false; .\)e

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read_nPos(); S3QX{5t\  
} B
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else {n<1uh9~$8  
{ UD5
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nStartPos = new long[bean.getNSplitter()]; |h((SreO  
nEndPos = new long[bean.getNSplitter()]; u)/i$N  
} 'g}Q@@b  
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} o_ixdnc  
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public void run() Cs,t:aj
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{ ,ob)6P^rw  
//获得文件长度 Q%V530 P;  
//分割文件 u2U+uD@yA  
//实例FileSplitterFetch wNh\pWA  
//启动FileSplitterFetch线程 ]*{tno  
//等待子线程返回 'X_%m~}N  
try{ =;?Maexp3$  
if(bFirst) x51xY$
M  
{ H4M`^r@)'  
nFileLength = getFileSize(); \#"&S@%c  
if(nFileLength == -1) q _:7uQ  
{ /q"8sj/  
System.err.println("File Length is not known!"); )G#O#Yy
  
} 3Ea/)EB]  
else if(nFileLength == -2) BG]|iHi  
{ g\aq#QV  
System.err.println("File is not access!"); lXnv(3j3*s  
} %kQ[zd^  
else Dkg-y9  
{ CzmB76zy.  
for(int i=0;i<nStartPos.length;i++) Z22#lF\N  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); zWF[cf>'  
} q~xs4?n1U  
for(int i=0;i<nEndPos.length-1;i++) ^c){N-G  
{ 8`WaUB%  
nEndPos = nStartPos[i+1]; ^Uik{x  
} C33RXt$X  
nEndPos[nEndPos.length-1] = nFileLength; ZM57(D  
} sHSg _/|  
} 5hlS2fn  
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//启动子线程 - KaU@t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cA!o xti  
for(int i=0;i<nStartPos.length;i++) ovvg"/>L  
{ 7X.B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V?jot<|$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o&?:pE  
nStartPos,nEndPos,i); l<s6Uu"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <VT|R~  
fileSplitterFetch.start(); okbW. ~  
} [R/'hH5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qf}}/k|)k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TM,Fab &  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g6.Tx]?b$  
nEndPos = " + nFileLength); (.g?|c  
// fileSplitterFetch[nPos.length-1].start(); OX{2@+f#  
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}eLth0d`'o  
//等待子线程结束 73+)> "x>  
//int count = 0; H4ancmy  
//是否结束while循环 $~1~+s0$  
boolean breakWhile = false; e:n3@T,
R  
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while(!bStop) ygqWy1C  
{ XhJYsq]]J  
write_nPos(); .:SY:v r  
Utility.sleep(500); ?]58{O(?c  
breakWhile = true; /)XN^Jwa;m  
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for(int i=0;i<nStartPos.length;i++) z?C&,mv
 
{ vu_ u\2d  
if(!fileSplitterFetch.bDownOver) }h9f(ZyJn  
{ wf,w%n  
breakWhile = false; ">Y(0^^  
break; VCvFCyAz  
} ~J|B  
} jd}-&DN  
if(breakWhile) XchVsA  
break; wv&%09U  
F{ sPQf'  
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//count++; x I(X+d``  
//if(count>4) Y;>D"C..  
// siteStop(); j55OG~)  
}
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System.err.println("文件下载结束！"); RJ$x{$r[  
} $Rf)iW;h  
catch(Exception e){e.printStackTrace ();} B3@\Ua)  
} #Dl=K<I  
'/<f'R^  
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//获得文件长度 _'U(q\ri  
public long getFileSize() s)7sgP  
{ $6*6%T5}  
int nFileLength = -1; x^6b$>1  
try{ Q=F4ZrNqD  
URL url = new URL(siteInfoBean.getSSiteURL()); 70T{tB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q>l5:2lq  
httpConnection.setRequestProperty("User-Agent","NetFox"); G"F:68  
N/r8joi#  
}x?2txuu  
int responseCode=httpConnection.getResponseCode(); U oG+du[  
if(responseCode>=400) $5J~4B"%3  
{ I{uwT5QT-  
processErrorCode(responseCode); [Qn$i/`J  
return -2; //-2 represent access is error c7t.  
} &>
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String sHeader; &K-0ld(;  
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for(int i=1;;i++) sx@%3j  
{ FYX"q-Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c"`CvQO64  
//Utility.log(in.readLine()); _|s'0F/t  
sHeader=httpConnection.getHeaderFieldKey(i); {M P(*N  
if(sHeader!=null) 9wpV} .(  
{ U$wD'v3pw  
if(sHeader.equals("Content-Length")) t}f,j^`e  
{ ~cb7]^#u1l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QK(w2`  
break; xcE<|0N :  
} ,2`F
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} )|E617g  
else 05Y4=7,!  
break; &4jc3_UKV  
} !ZzDSQ;  
} K7}]pk,AG  
catch(IOException e){e.printStackTrace ();} uN9J?j*ir  
catch(Exception e){e.printStackTrace ();} TX$4x~:  
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Utility.log(nFileLength); ExZ|_7^<  
+`'>  
3 cF4xUIZ  
return nFileLength; !A&>Eeai  
} @ACq:+/Qc  
m"RSDM!  
!6l}s$1i|  
//保存下载信息（文件指针位置） rtZEK:.#  
private void write_nPos() ja+PVf  
{ ]r(s02  
try{ uxsi+vkI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L_Lhmtm}m  
output.writeInt(nStartPos.length); @agxu-Y  
for(int i=0;i<nStartPos.length;i++) KU*XRZu)  
{ 9;`E,w  
// output.writeLong(nPos); <@J0 770  
output.writeLong(fileSplitterFetch.nStartPos); HCZVvsG  
output.writeLong(fileSplitterFetch.nEndPos); G)3Q|Vc  
} P|QM0GI  
output.close(); -5d^n\CDK  
} J @^Ypq  
catch(IOException e){e.printStackTrace ();} #B!<gA$/  
catch(Exception e){e.printStackTrace ();} tlpTq\;  
} Ula h!s  
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//读取保存的下载信息（文件指针位置） `xF^9;5mi  
private void read_nPos() Qk]^]I  
{ f7oJ6'K  
try{ ],l\HHQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s|9[=JMG  
int nCount = input.readInt(); ND\M  
nStartPos = new long[nCount]; 2OsS+6,[x  
nEndPos = new long[nCount]; !6*m<#Qm  
for(int i=0;i<nStartPos.length;i++) /SD(
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{ BL1d=%2R  
nStartPos = input.readLong(); B2l5}"{`  
nEndPos = input.readLong(); Fb\ E39  
} :'X:cL  
input.close(); wL~-k  
} HJt@m &H|  
catch(IOException e){e.printStackTrace ();} 8\Kpc;zb  
catch(Exception e){e.printStackTrace ();} n'qWS/0U=  
} BKk+<#Ti  
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private void processErrorCode(int nErrorCode) ,j e  
{ r&ux|o+  
System.err.println("Error Code : " + nErrorCode); lkJ"f{4f  
} QyD(@MFxb  
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k]9+/$  
//停止文件下载 tx,q=.(  
public void siteStop() rBZ0Fx$/[  
{ W}'l8z]   
bStop = true; Mew,g:m:  
for(int i=0;i<nStartPos.length;i++) %Z+FX,AK  
fileSplitterFetch.splitterStop(); H_FT%`iM  
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} &.[I}KH|B  
} <7_s'UAL!  
//负责部分文件的抓取 ?ZP@H _w6}  
**FileSplitterFetch.java tui5?\  
*/ =hi{J M  
package NetFox; qijQRxS  
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(CInt_dBw~  
import java.io.*; o^v]d7I8b  
import java.net.*; Nj=0bg"Qg5  
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public class FileSplitterFetch extends Thread { cyBm,!  
lx:.9>  
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String sURL; //File URL BKKW3PT  
long nStartPos; //File Snippet Start Position <kKuis6h  
long nEndPos; //File Snippet End Position ;e0-FF+  
int nThreadID; //Thread's ID &X#6jTh+  
boolean bDownOver = false; //Downing is over
r7-H`%.  
boolean bStop = false; //Stop identical }h1y^fuGi  
FileAccessI fileAccessI = null; //File Access interface uSUog+i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @]7s`?  
{ {'sp8:$a  
this.sURL = sURL; [C{oj*"c]  
this.nStartPos = nStart; 3L:SJskYR  
this.nEndPos = nEnd; mwO9`AU;  
nThreadID = id; ujS
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 sq{=TB{  
} WOi+y   
}U|0F#0$  
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public void run() :QIf0*.O  
{ Nr?CZFN#  
while(nStartPos < nEndPos && !bStop) +<bvh<]Od  
{ ^
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@]etW>F_  
try{ kQD~v+u{`  
URL url = new URL(sURL); TeKU/&fkc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p %hv
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httpConnection.setRequestProperty("User-Agent","NetFox"); 9Y+7o%6e  
String sProperty = "bytes="+nStartPos+"-"; '0v]?mM  
httpConnection.setRequestProperty("RANGE",sProperty); OmlM9cXm^4  
Utility.log(sProperty); BvP++,a&Sa  
-?w3j9kk>  
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InputStream input = httpConnection.getInputStream(); |_OoD9,M  
//logResponseHead(httpConnection); %LBf'iA  
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ndu$N$7+  
byte[] b = new byte[1024]; 9r>iP L2H  
int nRead; 9SXpZ*Sx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3hcWR'|  
{ <[vsGUbc  
nStartPos += fileAccessI.write(b,0,nRead); f`YHZ O  
//if(nThreadID == 1) 49= K]
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (t5vBUj  
} EQ]>^VE2B  
v%7Gh-P  
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Utility.log("Thread " + nThreadID + " is over!"); Z-3("%_$/  
bDownOver = true; +V;d^&S  
//nPos = fileAccessI.write (b,0,nRead); }=A+W2D  
} eOahr
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catch(Exception e){e.printStackTrace ();} =R*IOJ  
} cZ3A~dTOR  
} A3|2;4t  
+mN8uU~(kx  
NfZC}  
//打印回应的头信息 +xQj-r)-  
public void logResponseHead(HttpURLConnection con) g){gF(  
{ @(IA:6GN  
for(int i=1;;i++) 4lI&y<F  
{ n.Y45(@E  
String header=con.getHeaderFieldKey(i); `
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if(header!=null) -$I$zo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EAHdt=8W{  
Utility.log(header+" : "+con.getHeaderField(header)); OZ/"W)  
else E {UhM q7  
break; .  LeS-  
} h-fm)1S_  
} 5a4i)I63o  
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public void splitterStop() !Wj`U$];  
{ 3xgU=@!;  
bStop = true; =&PO_t5)z  
} hqV_MeHv'  
@u`m6``T  
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} Y=,9M  
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/* GK1P7Qy?V  
**FileAccess.java =i6k[rg  
*//文件访问(定位，写) OS1f}<  
package NetFox; _-2;!L#/  
import java.io.*; !wC( ]Y  
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?v`24p3PC  
public class FileAccessI implements Serializable{ PP]7_h^2  
C3~O6<,Jh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &UO/p/a
 
RandomAccessFile oSavedFile; 93
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long nPos; V."cmtf  
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public FileAccessI() throws IOException 7jGfQ  
{ 0}po74x*r  
this("",0); 'j!n   
} {XV'C@B  
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]YOWCFAQot  
public FileAccessI(String sName,long nPos) throws IOException TaF;PGjVw  
{ bdEIvf7  
oSavedFile = new RandomAccessFile(sName,"rw"); lqa~ZF*  
this.nPos = nPos; yqR]9"a  
oSavedFile.seek(nPos); "sWsK %  
} x$FcF8  
<9c{Kt.5(  
wk'&n^_br  
public synchronized int write(byte[] b,int nStart,int nLen) d. ZfK  
{ Eo6qC?5<  
int n = -1; $LcMG,8%_  
try{ b1G6'~U-  
oSavedFile.write(b,nStart,nLen); '&$zgK9T?  
n = nLen; X&Sah}0V&  
} 8"p rWAN  
catch(IOException e) 1H-~+lf  
{ N#@v`S  
e.printStackTrace (); '8FH
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} .v-2A);I  
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rw  
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return n; Mb45UG#2  
} ZE1${QFkG  
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} KTwP.!<v  
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s3'kzwX  
/* Fc=6*.hy  
**SiteInfoBean.java 7]~|dc(  
*/ M1T.  
package NetFox; m"6K_4r]  
p#3G=FV  
 m3^D~4  
public class SiteInfoBean {
mx#)iHY  
sCp)o,;  
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private String sSiteURL; //Site's URL ,?`kYPZ  
private String sFilePath; //Saved File's Path ly6dl
 
private String sFileName; //Saved File's Name [Dmf.PUe  
private int nSplitter; //Count of Splited Downloading File fwh/#V-i  
R<%{I)  
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public SiteInfoBean() ooP{Q r  
{//nSplitter的缺省值为5 o 9(x\g  
//default value of nSplitter is 5 P% 8U  
this("","","",5); 3,#v0#  
} Ndyo)11z
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s6#e?5J  
{ Ps;4]=c  
sSiteURL= sURL; N/<c;"o  
sFilePath = sPath; _H-Fm$Q  
sFileName = sName; PO^#G@  
this.nSplitter = nSpiltter; Zq H-]?)  
qT&zg@m  
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} ?6L8#"=  
9
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!|z!e>0  
public String getSSiteURL() b!teSf  
{ .[1@wW&L  
return sSiteURL; *P&lAyt6  
} g>`D!n::n  
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GiXs`Yt|  
public void setSSiteURL(String value) 5@ Hg 4.  
{ 9xE_Awlc85  
sSiteURL = value; D9hq$?
  
} z4zPR?%:  
4Lz[bI  
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public String getSFilePath() oq b(w+<  
{ |KO[[4b ?+  
return sFilePath; m Ph=bG  
} "?FBbJ  
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!f}D*8\f  
public void setSFilePath(String value) KTAQ6k  
{ &7\fj  
sFilePath = value; fu-,<m{  
} K4I/a#S'@6  
2L51H(  
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public String getSFileName() yS3or(K  
{
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return sFileName; h##U=`x3  
} n</Rd=  
=}Q|#C  
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public void setSFileName(String value) Fq%NY8KNE  
{ 8-cuaa  
sFileName = value; qv|}>wU  
} KP$AT}D  
Vn\jU
EC  
j0w@ \gO<  
public int getNSplitter() 8:0,jnS  
{ Der'45]*^  
return nSplitter; fKtlfQG  
} txQr|\4k  
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public void setNSplitter(int nCount) &l4kwds R  
{ mHJGpJ=a-  
nSplitter = nCount; $1Wb`$  
} 5fz K*[B  
} AsvH@
\\  
AVfF<E/  
F IB)cpo  
/* }9!}T~NMs  
**Utility.java uc|ej9N  
*/ bqaj~:}@  
package NetFox; H]f[r~  
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Vl>KeZ+  
public class Utility { -"^xg"  
sD&V_ &i  
{>XoE %  
public Utility() EB6X Yr
 
{  5PC:4  
17 
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7#7|+%W0  
} rp2g./2  
!\O!Du  
//线程睡眠 FJxb!-0&  
public static void sleep(int nSecond) mAJ'>^`^  
{ Kb1@+  
try{ r:4]:NKCi  
Thread.sleep(nSecond); ]KG.-o30  
} h~z}N
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catch(Exception e) u0g"x_3  
{ L{&=SR.  
e.printStackTrace (); yNU}1_oK  
} {z;4t&5  
} " SP6o  
Xs'qwL~{`  
//日志 >
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public static void log(String sMsg) =^_a2_BBl  
{ G2+ gEg  
System.err.println(sMsg); {vZAOz7#  
} u`Y~r<?P(  
d\tY-X3  
FV,aQ#  
public static void log(int sMsg) k`5K&  
{ )|AxQP
d  
System.err.println(sMsg); -
})zRL0!'  
} K@ &;f(Y  
} M-q5Jfm  
>.G#\w  
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/* b*{UO  
**TestMethod.java $jv"$0Fc  
*/ %Nob B  
package NetFox; WN#2<XjG  
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#JXXq%4 @  
public class TestMethod { UN:qE oS  
3TS:H1n  
D,(:))DmR  
public TestMethod() ,ei=w,
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{ ///xx/weblogic60b2_win.exe T7O)  
try{ QXl~a%lB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e$JATA:j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w*o2lg9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !- 5z 1b)  
fileFetch.start(); XdOntP*a  
} WW!-,d{{@  
catch(Exception e){e.printStackTrace ();} Mm9*$g!R  
5@I/+D  
"}H2dn2n  
} a0Fq$  
-%{+\x2  
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public static void main(String[] args) 5P 5Tgk  
{ cR*~JwC:  
new TestMethod(); AEElaq.B  
} {MDM=;WP_  
} ]#G1 ]U  
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