http断点续传简单实现（java)

/* TfZ6F8|B  
**SiteFileFetch.java +1Ph<zq"  
*/ 2~p[7?sp'  
package NetFox; ]AS"z<  
import java.io.*; OAZ#|U   
import java.net.*; 7W9d6i)  
\hP=-J[~C  
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public class SiteFileFetch extends Thread { M}"r#Plq  
+f;CyMEp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nxap\Lf  
long[] nStartPos; //开始位置 n1:v HBM@\  
long[] nEndPos; //结束位置 Er:?M_ev  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;;gK@?hJ  
long nFileLength; //文件长度 A~{f/%8D  
boolean bFirst = true; //是否第一次取文件 k6?cP0I)5  
boolean bStop = false; //停止标志 YY4-bNj[p  
File tmpFile; //文件下载的临时信息 7/X"z=Q^|  
DataOutputStream output; //输出到文件的输出流 7yiJ1K<bIt  
6j8<Q 2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +MO E  
public SiteFileFetch(SiteInfoBean bean) throws IOException &,-p',\
-  
{ 9;r? nZT
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siteInfoBean = bean; H.J5i~s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SLk2X;c]o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~HUZ#rUHm>  
if(tmpFile.exists ()) qG>DTKIU  
{ +ydm,aKk  
bFirst = false; 8]0:1 {@  
read_nPos(); 8h?X!2Nq  
} m<3v)R[>  
else O'}llo  
{ 2N6=8Xy5K  
nStartPos = new long[bean.getNSplitter()]; ^4`&EF  
nEndPos = new long[bean.getNSplitter()]; G\Q9IcJ0dY  
} #Y,A[Y5jX  
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} n'64;J5  
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public void run() iWXMKu  
{ yCM{M  
//获得文件长度 Y%vP#>h  
//分割文件 \kwe51MQ  
//实例FileSplitterFetch S[@6Lp3q_  
//启动FileSplitterFetch线程 Yn[x #DS  
//等待子线程返回 &?$\Y,{  
try{ 6hbEO-(  
if(bFirst) iiwpSGFl]  
{ PF ;YE6  
nFileLength = getFileSize(); {u]CHN`%Z  
if(nFileLength == -1) ^L~ [+|  
{ 8)Tj
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System.err.println("File Length is not known!"); <J#R3{  
} #DaP=k"XV  
else if(nFileLength == -2) X"J%R/f  
{ lgG8!Ja  
System.err.println("File is not access!"); 9c5!\m1  
} V/UB9)i+  
else aVK()1v]  
{ CB@B.)E  
for(int i=0;i<nStartPos.length;i++) 0e9A+&r  
{ .xv^G?GG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ECdfLn*c  
} ag/u8  
for(int i=0;i<nEndPos.length-1;i++) /2:Q6J  
{ v=+k"gm6  
nEndPos = nStartPos[i+1]; 7dhn'TW  
} V9$-twhu  
nEndPos[nEndPos.length-1] = nFileLength; ?HxS)Pqq  
} #8qyg<F  
} \R;K>c7=  
) hPVX()O!  
y%g`FC   
//启动子线程 }`@?X"r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <
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for(int i=0;i<nStartPos.length;i++) <\xQ7|e  
{ fsb=8>}63}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E#~2wqK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1'OD3~[R  
nStartPos,nEndPos,i); R]fYe#!"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L3' \r  
fileSplitterFetch.start(); <VgE39 [  
} Bzm.X=U:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Lj-{t% }  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `i{4cT8:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o9^$hDs,si  
nEndPos = " + nFileLength); c; d"XiA  
// fileSplitterFetch[nPos.length-1].start(); :EaiM J_=  
QZ9M{Y/  
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//等待子线程结束 8Y]}Gb!  
//int count = 0; 7vdHR\#;$  
//是否结束while循环 zVn*!c  
boolean breakWhile = false; y#GCtkhi  
'NRN_c9  
s=}~Q&8  
while(!bStop) C
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{ pIrv$^  
write_nPos(); mKMGdN~  
Utility.sleep(500); >cSi/a,L  
breakWhile = true; jBGG2[hV  
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for(int i=0;i<nStartPos.length;i++) N_*u5mfQX  
{ L_`Xbky  
if(!fileSplitterFetch.bDownOver) =54Vs8.  
{ kkG_ +Y  
breakWhile = false; e*6U |+kJ  
break; SIJ# ?0,  
} =k_XKxd  
}
Fj36K6!#?  
if(breakWhile) >zN" z)  
break; "o~N42DLB%  
,OFq'}q  
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//count++; #.RG1-L  
//if(count>4) |q9,,i}!  
// siteStop(); | 3hT{  
} DHSU?o#jY  
(bM)Nd  
k,yc>3P;U  
System.err.println("文件下载结束！"); 7Q<Kha  
} 0#2T0zk  
catch(Exception e){e.printStackTrace ();} m[//_TFf]  
} 8b8e^\l(  
ktkn2Twa/  

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//获得文件长度 )ylv(qgV  
public long getFileSize() "Yc^Nc  
{ /7!_un9  
int nFileLength = -1; 8T!fGzHx  
try{ ym-lT|>Z  
URL url = new URL(siteInfoBean.getSSiteURL()); - I1cAt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m? ]zomP  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^\Ue7,H-  
'2Mjz6mBDA  
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int responseCode=httpConnection.getResponseCode(); ^!-E`<jW8  
if(responseCode>=400) $cp16  
{ 'b?#4rq}  
processErrorCode(responseCode); [e
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return -2; //-2 represent access is error Xs.$2  
} S|O%h}AH;  
]
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String sHeader; `2Z4#$.  
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for(int i=1;;i++) )U"D4j*p  
{ dvrvpDoE.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OXa5Jg}=  
//Utility.log(in.readLine()); Ah8^^h|TPJ  
sHeader=httpConnection.getHeaderFieldKey(i); troy^H  
if(sHeader!=null) tq4"QBIKh  
{ )edU <1P  
if(sHeader.equals("Content-Length")) g9grfN  
{ zO7lsx2=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;N> {1  
break; ?fqkM  
} o0-fUCmC  
} KNUMz4  
else ;_Of`C+  
break; )U/@J+{{  
} ?*MV ^IY  
} p8}5x 2F  
catch(IOException e){e.printStackTrace ();} *BP\6"X  
catch(Exception e){e.printStackTrace ();} 1Q2k>q8  
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Utility.log(nFileLength); ?@,f[U-  
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return nFileLength; }GU6Q|s[u[  
} ;?Y`e  
"*H'bzK  
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//保存下载信息（文件指针位置） Sv^'CpQ  
private void write_nPos() [gg7Z|Hu  
{ | xErA  
try{ #mz,HK0|aC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LBiv]3  
output.writeInt(nStartPos.length); KWuj_.;  
for(int i=0;i<nStartPos.length;i++) T\b";+!W  
{ N6m*xxI{  
// output.writeLong(nPos); `QyALcO  
output.writeLong(fileSplitterFetch.nStartPos); Q1>Op$>h  
output.writeLong(fileSplitterFetch.nEndPos); { P\8g8  
} Wp~4[f`,  
output.close(); ,h)T
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} ePcI^}{  
catch(IOException e){e.printStackTrace ();} 0g*r!aa  
catch(Exception e){e.printStackTrace ();} HDae_.  
} ~ dI&> CL  
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//读取保存的下载信息（文件指针位置） W;AWO0+  
private void read_nPos() B,na  
{ p/^\(/\])  
try{ =D"63fP1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nz;*;BQK:  
int nCount = input.readInt(); ~9ls~$+*  
nStartPos = new long[nCount]; i:N^:%  
nEndPos = new long[nCount]; #*aGzF  
for(int i=0;i<nStartPos.length;i++) ;g)Fhdy!  
{ QT&Ws+@ s{  
nStartPos = input.readLong(); y2hFUq
  
nEndPos = input.readLong(); vgbjvyfN  
} ZK_@.O+]  
input.close(); GWE0 UO}  
} ~FrkLP  
catch(IOException e){e.printStackTrace ();} {{)[Ap)  
catch(Exception e){e.printStackTrace ();} 1AkHig,  
} N(/<q
v  
9h0,L/;\  
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private void processErrorCode(int nErrorCode) O0*L9C/Q  
{ 6!D  
System.err.println("Error Code : " + nErrorCode); N~<}\0  
} %-p{?=:K  
+T-zf@j  
xgw)`>p,W  
//停止文件下载 7Mg7B
  
public void siteStop() b2-|e_x  
{ NX #d}M^V  
bStop = true; + d)~;I$  
for(int i=0;i<nStartPos.length;i++) `}Zbfe~  
fileSplitterFetch.splitterStop(); p:>?  
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} 2o}G<7r  
} r!gCh`PiK  
//负责部分文件的抓取 IMw)X0z  
**FileSplitterFetch.java qvT+d l3#[  
*/ v5ddb)  
package NetFox; &>B>+}'
 
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72.IhBNtT  
import java.io.*; /;m!>{({)  
import java.net.*; e>9{36~jh  
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public class FileSplitterFetch extends Thread { y:zT1I@>  
[!efQap  
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String sURL; //File URL 
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long nStartPos; //File Snippet Start Position vszAr
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long nEndPos; //File Snippet End Position Y]0y -H  
int nThreadID; //Thread's ID eL4@% ]o  
boolean bDownOver = false; //Downing is over ,/U9v~  
boolean bStop = false; //Stop identical W/X;|m`  
FileAccessI fileAccessI = null; //File Access interface {NqGWkGt*b  
qf$|
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J%B?YO,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~i#xjD5  
{ BV:,bS  
this.sURL = sURL; lhODNWi
 
this.nStartPos = nStart; {oeQK  
this.nEndPos = nEnd; R6.#gb8^oS  
nThreadID = id; 4 V*)0?oYE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D4-U[l+K>  
} &y+*3,!n8  
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public void run() /YR$#&N2  
{ 55KL^+-~  
while(nStartPos < nEndPos && !bStop) IsL/p3|  
{ ,gD i)]  
[=!MS?-G  
^:j:;\;  
try{ %/C[\wp81  
URL url = new URL(sURL); <a3XV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q
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httpConnection.setRequestProperty("User-Agent","NetFox"); .r"?w  
String sProperty = "bytes="+nStartPos+"-"; A+8b]t_k  
httpConnection.setRequestProperty("RANGE",sProperty); IGQ8-#=  
Utility.log(sProperty); @h3)!#\N  
"G(/MT^C  
 {`  
InputStream input = httpConnection.getInputStream(); 31Du@h8YX  
//logResponseHead(httpConnection); 4(IP  
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byte[] b = new byte[1024]; mg]dKp  
int nRead; [%Xfl7;Wh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ ?Fv(4g  
nStartPos += fileAccessI.write(b,0,nRead); 
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//if(nThreadID == 1) WLb7]rCTp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 58,mu#yq6  
} $!w%=  
{D< ?.'  
]Hq%Q~cE  
Utility.log("Thread " + nThreadID + " is over!"); y0]O 6.{  
bDownOver = true; IuD<lMeJJ  
//nPos = fileAccessI.write (b,0,nRead); y 6<tV.  
} [j39A`t7 o  
catch(Exception e){e.printStackTrace ();} } d6^  
} LLiX%XOh  
} cB^lSmu5  
C? S%fF  
)-gyDA
 
//打印回应的头信息 s]UeDZ<a  
public void logResponseHead(HttpURLConnection con) )1le-SC  
{ 6yqp<D0SP)  
for(int i=1;;i++) KW\`&ki  
{ ]vMft?  
String header=con.getHeaderFieldKey(i); |.5d^z  
if(header!=null) (B5G?cB9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Vv]mME@  
Utility.log(header+" : "+con.getHeaderField(header)); PX]v"xf  
else fmh]Y/UC  
break; =9-c*bL  
} &/p9+gd  
} l"/Os_4O  
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public void splitterStop() rcCMx"L=  
{ gC_U7aw  
bStop = true; "PPwJ/L(  
} t [f]  
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} } 2KuY\5\i  
f|!
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/* y$rp1||lH  
**FileAccess.java G6FknYj  
*//文件访问(定位，写) <#sK~G  
package NetFox; $|KbjpQ  
import java.io.*; 'tekn
e  
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wXe.zLQ  
public class FileAccessI implements Serializable{ G"]'`2.m  
Wuk
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _:J! |'  
RandomAccessFile oSavedFile; 74_ji!  
long nPos; t5S S]  
pV_2JXM~@  
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public FileAccessI() throws IOException #H|]F86(  
{ sNWj+T  
this("",0); dXZV1e1b&#  
} d4/ZOj+%  
3LG)s:p$/  
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public FileAccessI(String sName,long nPos) throws IOException :7'anj  
{ P69S[aqW  
oSavedFile = new RandomAccessFile(sName,"rw"); "Mth<%i  
this.nPos = nPos; Gmc
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oSavedFile.seek(nPos); 8D-g%Aj-  
} @AJt/wPk  
@l 1 piz8  
4q2aVm  
public synchronized int write(byte[] b,int nStart,int nLen) DF<_
Ns!  
{ N G4wtDa  
int n = -1; a4?:suX$  
try{ !I@"+oY<  
oSavedFile.write(b,nStart,nLen); \\
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n = nLen; KdUmet
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} YDP<  
catch(IOException e) fN@2 B  
{ 2|+**BxHD  
e.printStackTrace (); 13Q|p,^R  
} vtmvvv  
o@}Jd0D4  
^b'[81%  
return n; ^8DC W`V  
} ^J?I-LG  
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} ~b*f2UVs  
]*?qaIdqu  

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0  
/* .7" f~%&oP  
**SiteInfoBean.java SBs_rhe  
*/ WI' ;e4  
package NetFox; |nIm$
p'  
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iphe0QE[#}  
public class SiteInfoBean { bmFnsqo  
mJl|dk_c  
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private String sSiteURL; //Site's URL wj/OYnMw  
private String sFilePath; //Saved File's Path GHfsq|*j,Z  
private String sFileName; //Saved File's Name s+l)Q  
private int nSplitter; //Count of Splited Downloading File 5\lOZYHX  
D3N\$D  
-:&qNY:Vp  
public SiteInfoBean() j'
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{//nSplitter的缺省值为5 "aHA6zTB  
//default value of nSplitter is 5 $ba3dqbCW  
this("","","",5); s0WI93+z  
} 0& 54xP  
{dTtYL$'"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Mt"j<
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{ ^^1
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sSiteURL= sURL; %3
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sFilePath = sPath; l.Iov?e1S  
sFileName = sName; 9q(*'rAm  
this.nSplitter = nSpiltter; zo4 IY`3  
(< gk<e*  
bdEc?  
} &z8I@^<  
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&==X.2XW  
public String getSSiteURL() nO.RB#I$F  
{ [oqb@J2  
return sSiteURL; ~`~mnlN  
} w,f1F;!q1  
_Z'[-rcXWh  
9x$Kb7'F  
public void setSSiteURL(String value) mWN9/+!  
{ u2}zRC=  
sSiteURL = value; (r78AZ  
} LX5, _`B  
ruiAEC<Ej  
 _8]h
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public String getSFilePath() WCJ$S\#  
{ `tZm  
return sFilePath; T$
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} "-bsWC  
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public void setSFilePath(String value) #4?Z|_j3  
{ pH!e<m  
sFilePath = value; &b~if}vcb  
} ` 9iB`<  
9OI&De5?=V  
`q":i>FP2  
public String getSFileName() !5FZxmUup  
{ /-J12O  
return sFileName; ]m&cVy&  
} ?2LRMh")$  
>Z-f</v03  
vQK*:IRKK  
public void setSFileName(String value) Pi7IBz  
{ rsSE*(T t  
sFileName = value; `GGACH3#s  
} 4Og&w]  
B}Lz#'5_  
T;{M9W+  
public int getNSplitter() +T\c<lJ9  
{ '(N -jk  
return nSplitter; t>]wWYy  
} T8*<  
6@N?`6Bt  
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public void setNSplitter(int nCount) mI;#Zq_j  
{ Gn+3OI"  
nSplitter = nCount; iobL6SUZ  
} 4&TTPcSt;  
} <0?h$hf4c  
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8`edskWrU  
/* ]6#7TT  
**Utility.java Hjho!np  
*/ b ] W^_
 
package NetFox; e@B
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: 5=E>!  
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public class Utility { !%pY)69gv  

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public Utility() jSY&P/[xb  
{ 2d%j6D  
auzrM4<tz  
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} *TacVp  
H[K(Tt4<&  
//线程睡眠 Ib$*w)4:  
public static void sleep(int nSecond) {|
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{ 1r %~Rm  
try{ 8A|{jH74  
Thread.sleep(nSecond); bC[TLsh7{2  
} Cpyv@+;D  
catch(Exception e) <4
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{ [P'crV,m  
e.printStackTrace (); je9eJUKE  
} ]klP.&I/0  
} bo;;\>k  
l?_h(Cq<  
//日志 c^N'g!on  
public static void log(String sMsg) $}{u6*u.,  
{ TB=KTj  
System.err.println(sMsg); vrS)VJg`  
} H<^*V8J 'w  
tcovMn'  
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public static void log(int sMsg) OHz>B!`  
{ {i:5XL   
System.err.println(sMsg); :'\4%D=w  
} x2P}8Idg?A  
} Bl)znJ^
 
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r*-e~  
/* @uIY+_E40g  
**TestMethod.java @B<B#  
*/ <NIg`B@'s  
package NetFox; $On  
-c^/k_n  
e ]@Ex  
public class TestMethod { GCw<jHw  
<tT*.n
M\  
3f 1@<7*  
public TestMethod() f87>ul!*  
{ ///xx/weblogic60b2_win.exe r_sZw@lqJ  
try{ >JNK06T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (<u3<40[YN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
|!0R"lv'u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ZI<p%IQ  
fileFetch.start(); ##%R|P3  
} m,zZe}oJ  
catch(Exception e){e.printStackTrace ();} P#
_8$#G3  
/eM_:H5  
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} /}~; b#t  
*`}4]OGv.  
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public static void main(String[] args) 5W0'r'{  
{ won(HK\1p  
new TestMethod(); G4!$48  
} $EHnlaG8r  
} ^1&xt(G  
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