http断点续传简单实现（java)

/* Xw |6 #^  
**SiteFileFetch.java >{@:p`*  
*/ {u{8QKeC  
package NetFox; jz"-E  
import java.io.*; `d6,]'  
import java.net.*; .:V4>  
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public class SiteFileFetch extends Thread { c3q @]|aI  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #8;#)q_[u  
long[] nStartPos; //开始位置 j^qI~|#  
long[] nEndPos; //结束位置 ".:]?Lvt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 URb  
long nFileLength; //文件长度 cLyed3uU  
boolean bFirst = true; //是否第一次取文件 1J @43>u{  
boolean bStop = false; //停止标志 `(Ij@84  
File tmpFile; //文件下载的临时信息 7zEpuw  
DataOutputStream output; //输出到文件的输出流 NQqq\h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lJ/{.uK  
public SiteFileFetch(SiteInfoBean bean) throws IOException $mLiEsJ  
{ v7@O ,%  
siteInfoBean = bean; @1^:V-=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X Cf!
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0|D l/
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if(tmpFile.exists ()) e=Teq~K  
{ $ Ov#^wfA  
bFirst = false; _ pKWDMB$z  
read_nPos(); m.DC  
} TB(!*t  
else VaLl$w  
{ |dI,4Z\Qb  
nStartPos = new long[bean.getNSplitter()]; #,PB(  
nEndPos = new long[bean.getNSplitter()]; fw+ VR.#2H  
} 
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} ]n$&|@  
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public void run() to"[r  
{ a-Ef$(i_  
//获得文件长度 $mZpX:7/u8  
//分割文件 CY i{WV(:  
//实例FileSplitterFetch ZK8I f?SD  
//启动FileSplitterFetch线程 Cv;\cI"&  
//等待子线程返回 JwMFu5@  
try{ [$P.ek<  
if(bFirst) k:k!4  
{ BLQD=?Q
  
nFileLength = getFileSize(); IWD21lS  
if(nFileLength == -1) %2t#>}If!  
{ FST}:*dOe5  
System.err.println("File Length is not known!"); ?2$0
aq  
} Ad]oM]  
else if(nFileLength == -2) T_1p1Sg  
{ 8w]>SEGFs  
System.err.println("File is not access!"); r(ufyC&  
} r]'Q5l4j6"  
else >HlQ+bl$xw  
{ [tY+P7j9)  
for(int i=0;i<nStartPos.length;i++) N>3X!K  
{ PZsq9;P$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z3>oUq{  
} HG)c\b  
for(int i=0;i<nEndPos.length-1;i++) qc6eqE  
{ EU@XLm6  
nEndPos = nStartPos[i+1]; )}i;OLw-  
} Q1(6U6L  
nEndPos[nEndPos.length-1] = nFileLength; Vuu_Sd  
} iJD_qhd7  
} 6*r3T:u3  
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k9iXVYQ.;r  
//启动子线程 baL-~`(T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I}{Xv#@o  
for(int i=0;i<nStartPos.length;i++) 6ISDY>p  
{ L.M|o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q\gvX 76a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mbm|~UwD  
nStartPos,nEndPos,i); ;%tu;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :\+\/H
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fileSplitterFetch.start(); ezR!ngt  
} %/(>>*}Kw|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \r+8}8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |~I-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A}cGag+sp  
nEndPos = " + nFileLength); {f }4l  
// fileSplitterFetch[nPos.length-1].start(); byUz  
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//等待子线程结束 G B&+EZ  
//int count = 0; gQ=g,
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//是否结束while循环 QC\][I>  
boolean breakWhile = false; U%,N"]`  
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2AZ)|dM'`  
while(!bStop) V*U*_Y  
{ :*wjC.Z  
write_nPos(); _hb@O2f  
Utility.sleep(500); ;uazQyo6  
breakWhile = true; t%f6P  
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for(int i=0;i<nStartPos.length;i++) @xI:ZtM  
{  4[]/  
if(!fileSplitterFetch.bDownOver) "x)xjL  
{ F]SA1ry  
breakWhile = false; $SmmrM  
break; {,aI0bw;  
} xE4iey@\}  
} *4tJ|m6"Y6  
if(breakWhile) pwvcH3l/r  
break; '~ {x
n  
< <vE.  
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//count++; NHCdf*  
//if(count>4) -OS&(7  
// siteStop(); u0(PWCi2
 
} d* 6 lJT  
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System.err.println("文件下载结束！"); @!:~gQ  
} l`vb  
catch(Exception e){e.printStackTrace ();} ByK!r~>Z1Q  
} ?(^HjRUY  
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//获得文件长度 '>]9efJA  
public long getFileSize() BF_R8H,<%  
{ RG)!v6
  
int nFileLength = -1; @KhDQ0v]5  
try{ (,gpR4O[  
URL url = new URL(siteInfoBean.getSSiteURL()); >*PZ&"}M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v){&g5djl  
httpConnection.setRequestProperty("User-Agent","NetFox"); f(h nomn  
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int responseCode=httpConnection.getResponseCode(); lKMOsr
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if(responseCode>=400) y0d a8sd)  
{ E2s lpo  
processErrorCode(responseCode); D9;2w7v  
return -2; //-2 represent access is error DJ)z~W2I*  
} ^0/FZ)V8  
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String sHeader; VV*Z5U@b  
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e `!PQMLU  
for(int i=1;;i++) X4:\Shb97  
{ 1jJ>(S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f;C*J1y  
//Utility.log(in.readLine()); p`
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sHeader=httpConnection.getHeaderFieldKey(i); :K ^T@F5n  
if(sHeader!=null) =7JvS~s  
{ t?:}bw+m  
if(sHeader.equals("Content-Length")) H+`s#'(i_P  
{ UvSvgDMl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (RR:{4
I  
break; Awo H d7M  
} Zr0b
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} tSVN}~1\  
else ,m-z D  
break; E|t.
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} ze<Lc/;X~  
} oh k.;  
catch(IOException e){e.printStackTrace ();} !1tHg Z2\  
catch(Exception e){e.printStackTrace ();} kCXQHX  
 :1q)l  
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Utility.log(nFileLength); &@O]'  
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return nFileLength; (j^Qa~{mG4  
} j~(s3pSCo  
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//保存下载信息（文件指针位置） uXX3IE[  
private void write_nPos() YRXXutm  
{ +*2]R~"M  
try{ @)A)cBv#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); '~HCYE:5  
output.writeInt(nStartPos.length); M]O _L  
for(int i=0;i<nStartPos.length;i++) CbmT aEaP  
{ /DG+8u  
// output.writeLong(nPos); b^wL{q  
output.writeLong(fileSplitterFetch.nStartPos); &_-,Nxsf  
output.writeLong(fileSplitterFetch.nEndPos); l^ P[nQDH  
} (!72Eaw:]  
output.close(); 4l/hh|3@  
} d NQ?8P-&  
catch(IOException e){e.printStackTrace ();} Yj/aa0Ka4  
catch(Exception e){e.printStackTrace ();} S+^*rw
  
} vUEG0{8l  
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 |,*N>e  
//读取保存的下载信息（文件指针位置） :+%"kgJNL  
private void read_nPos() LU
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{ DJxe3<  
try{ :DI``]Si\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;GW[Yw>Rz  
int nCount = input.readInt(); i6L>,^Dg  
nStartPos = new long[nCount]; `nAR/Ye  
nEndPos = new long[nCount]; !^{0vFWE  
for(int i=0;i<nStartPos.length;i++) D00I!D16  
{ woCmpCN*I  
nStartPos = input.readLong(); >K }j}M%  
nEndPos = input.readLong(); \qx$h!<  
} kvWP[! j?)  
input.close(); k3F*D  
} Y$3 &?LA  
catch(IOException e){e.printStackTrace ();} r5U[jwP  
catch(Exception e){e.printStackTrace ();} .<0|V  
} |'$E-[  
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private void processErrorCode(int nErrorCode) ]ow$VF{y  
{ Gwyjie9t  
System.err.println("Error Code : " + nErrorCode); [D!-~]5  
} KIyhvY~  
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//停止文件下载 =Q\z*.5j.  
public void siteStop() Rra3)i`
*  
{ =L,s6J8_'  
bStop = true; i2. +E&3v  
for(int i=0;i<nStartPos.length;i++) #2`ST=#  
fileSplitterFetch.splitterStop(); !GB\-(  
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} ,t"?~Hl".  
} =<,>dBs}\  
//负责部分文件的抓取 d']CBoK  
**FileSplitterFetch.java <>=A6
 
*/ }e/#dMEi  
package NetFox; %sd1`1In  
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import java.io.*; Ri[ v(Zf  
import java.net.*; DRp h?V\  
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public class FileSplitterFetch extends Thread { ]i$
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$ z4JUr!m  
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String sURL; //File URL <OX_6d*@  
long nStartPos; //File Snippet Start Position ( (.b&  
long nEndPos; //File Snippet End Position O!uZykdX4!  
int nThreadID; //Thread's ID K fM6(f:  
boolean bDownOver = false; //Downing is over DrAp&A|WV|  
boolean bStop = false; //Stop identical T;7=05k<_  
FileAccessI fileAccessI = null; //File Access interface u'Od~x^z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OoW,mmthj>  
{ ??\1eo2gB  
this.sURL = sURL; 41-u*$   
this.nStartPos = nStart; K1
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this.nEndPos = nEnd; ss{y=O%9"  
nThreadID = id; xIOYwVC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %Aqt0e  
} b-)m'B}`  
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public void run() mP!=&u fcU  
{ LS"_-4I}  
while(nStartPos < nEndPos && !bStop) s5`CV$bz  
{ !hMD>B2Z  
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try{ }s9eRmJs  
URL url = new URL(sURL); 6]%SSq&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,,FO6+4f  
httpConnection.setRequestProperty("User-Agent","NetFox"); wwvS05=[T  
String sProperty = "bytes="+nStartPos+"-"; ,@\$PyJ  
httpConnection.setRequestProperty("RANGE",sProperty); v&7yqEm}B  
Utility.log(sProperty); |:H 9#=  
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InputStream input = httpConnection.getInputStream(); hSl6X3W  
//logResponseHead(httpConnection); O V"5:){  
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byte[] b = new byte[1024]; UFE# J  
int nRead; Q1Jw7R#?l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "b~-`ni  
{ +'-i(]@!'  
nStartPos += fileAccessI.write(b,0,nRead); 6dH> 0
l  
//if(nThreadID == 1) hFW{qWP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J!\Cs1!f  
} g-C)y 06  
f9%M:cl  
;hf{B7  
Utility.log("Thread " + nThreadID + " is over!"); !7rk>YrY  
bDownOver = true; #F|q->2`o  
//nPos = fileAccessI.write (b,0,nRead); zl]Ic' _i  
} 8I>'xf  
catch(Exception e){e.printStackTrace ();} ??]b,f4CNa  
} n_ 3g  
} =<BPoGs5  
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' ?4\  
//打印回应的头信息 $D][_I  
public void logResponseHead(HttpURLConnection con) w\K(kNd(  
{ Wr j<}L|  
for(int i=1;;i++) 5bj9S  
{
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String header=con.getHeaderFieldKey(i); )yl
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if(header!=null) ln1QY"g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M?g
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Utility.log(header+" : "+con.getHeaderField(header)); G7qB
  
else 3D}rxI8N  
break; Ii.?| u  
} PHxU6UPqy  
} uo TTHj7cq  
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public void splitterStop() 0Tv0:c>8;(  
{ ZZ? KD\S5  
bStop = true; (r
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} "<N2TDF5  
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} af>^<q  
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/* +Oafo|%  
**FileAccess.java d71|(`&  
*//文件访问(定位，写) `Eg~;E:  
package NetFox; } %bP9  
import java.io.*; _SQQS67fu"  
g7l?/p[n  
d#U~
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public class FileAccessI implements Serializable{ kSfNu{YS  
rw }wQP_'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Zl\$9
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RandomAccessFile oSavedFile; _'}Mg7,V  
long nPos; q; ?Kmk  
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public FileAccessI() throws IOException 6JB*brO  
{ E4cPCQyeH  
this("",0); c}G\F$  
} VkD}gJY  
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public FileAccessI(String sName,long nPos) throws IOException >Tp`Kri  
{ 2[X\*"MQ2  
oSavedFile = new RandomAccessFile(sName,"rw"); G_E \p%L>]  
this.nPos = nPos; "nA~/t=  
oSavedFile.seek(nPos); 8dUP_t~d#q  
} ?ZAynZF|#  
4
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public synchronized int write(byte[] b,int nStart,int nLen) T(z/Jm3  
{ G6XDPr
:}  
int n = -1; Vpe\Okt:  
try{ %0_}usrsk  
oSavedFile.write(b,nStart,nLen); #JYH5:*  
n = nLen; ?m\? #  
} K9tr Iy$v  
catch(IOException e) -%ftPfm  
{ F T$x#>  
e.printStackTrace (); 0x2[*pJ|IW  
} 1EHL8@.M  
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return n;  V$fn$=  
} s?7"iE  
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} oC~+K@S  
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/* pC/13|I  
**SiteInfoBean.java aXgngwq  
*/ 7U2?in}?Qi  
package NetFox; _W  
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public class SiteInfoBean { y7T<Auue`  
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private String sSiteURL; //Site's URL k9!euj&  
private String sFilePath; //Saved File's Path 1'!%$D  
private String sFileName; //Saved File's Name sP@7%p>wt  
private int nSplitter; //Count of Splited Downloading File (2(y9r*1  
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public SiteInfoBean() BV)) #D9  
{//nSplitter的缺省值为5 vEc<|t  
//default value of nSplitter is 5 c+ukVn`r  
this("","","",5); Hn}m}A  
} @y/!`Ziw  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) giHqc7-PaX  
{ * zc[t  
sSiteURL= sURL; 3a0% J'  
sFilePath = sPath; K6 c[W%Va  
sFileName = sName; ?D+H2[n\a  
this.nSplitter = nSpiltter; _BI[F m  
}=fls=c/0  
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} UG=],\E2  
@e2
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-}  
public String getSSiteURL() p?O6|q  
{ hg-M>|s7  
return sSiteURL; 'xu!t'l&  
} 9dFo_a*?  
3|(3jIa  

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public void setSSiteURL(String value) |4!G@-2V:I  
{ Bejk^V~  
sSiteURL = value; /Q2HN(Y  
} >">grDX  
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E&;;2  
public String getSFilePath() XB<Q A>dLh  
{ P=m l;xp  
return sFilePath; o('6,D  
} H`nd |  
*})Np0k  
>"[Nmx0;w  
public void setSFilePath(String value) \xKhbpO~  
{ 5Un)d<!7&u  
sFilePath = value; t[:G45].-k  
} %&!B2z}  
,VZ<r5NT  
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public String getSFileName() NBD1k;  
{ 5zPn-1uW  
return sFileName; Q6r7UM  
} >/'/^h  
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public void setSFileName(String value) ~H:.&'E  
{ W)Mc$`nX  
sFileName = value; ?ajVf./Ja  
} \{54mM~  
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public int getNSplitter() 22Oe~W;  
{ A5~OHmeK  
return nSplitter; nTHCb>,vM  
} LZ8xh  
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public void setNSplitter(int nCount) 8u"HW~~=  
{ .[o`TlG%  
nSplitter = nCount; yGC3B00Z  
} $1n\jN  
} $*C'{&2  
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/* .50ql[En  
**Utility.java  AtP!.p"j  
*/ YXIAVSnr  
package NetFox; -o+; e3#  
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public class Utility { Z`>m  
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public Utility() d_ji ..T  
{ ~T9wx  
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} j# n  
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//线程睡眠 Ub`vf4EB  
public static void sleep(int nSecond) w~>tpkUB  
{ c"pu"t@/Z  
try{ gb/<(I )  
Thread.sleep(nSecond); Z<`:xFy(  
} cQq78Lo  
catch(Exception e) #NWS)^&1b  
{ qsdgG1<  
e.printStackTrace (); HAAU2A9B2  
} Wo~;h(6  
} g1&q6wCg|  
%(>,eee_  
//日志 z)%]#QO  
public static void log(String sMsg) pQk@ +r  
{ {GG;/Ns{f-  
System.err.println(sMsg); '1b4nj|<m  
} okH*2F(-  
VJgYXPE `  
?D=C8EX  
public static void log(int sMsg) #pk  
{ @k\npFKQm  
System.err.println(sMsg); U&gI_z[  
} d8&T62Dnd4  
} j5G=ZI86y  
,YF1*69  
KdC'#$  
/* mJ+mTA5bW  
**TestMethod.java 3+H[S#e:Z  
*/ @j=rSS  
package NetFox; /.Jq]"   
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public class TestMethod { TnJNs  
nTr{D&JS  
;8yEhar  
public TestMethod() FMz>p1s|dK  
{ ///xx/weblogic60b2_win.exe 'EG/)0t`  
try{ *@g>~q{`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cN~F32<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FLLfTkXdI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 15M!erT  
fileFetch.start(); b ; U  
} |};-.}u^`h  
catch(Exception e){e.printStackTrace ();} t<MO~_`!  
bCV_jR+  
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} ^a=V.  
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=L*-2cE6#  
public static void main(String[] args) Z*YS7 ~  
{ &+ UnPE(  
new TestMethod(); C&;m56  
} _xr@dK<   
} U$LI~XZM  
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