http断点续传简单实现（java)

/* +/4wioGm  
**SiteFileFetch.java Y]])Tq;h5  
*/ uo[W|Q  
package NetFox; IAzi:ct  
import java.io.*; k5/W'*P  
import java.net.*; UTR`jXC
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public class SiteFileFetch extends Thread { 1&#qq*{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a5nA'=|}i  
long[] nStartPos; //开始位置 FoB^iA6e  
long[] nEndPos; //结束位置 [ F7ru4"{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Dwuao`~Xm  
long nFileLength; //文件长度 Bbzmq  
boolean bFirst = true; //是否第一次取文件 &^1{x`Qo=  
boolean bStop = false; //停止标志 3T84f[CF
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File tmpFile; //文件下载的临时信息 br4?_,  
DataOutputStream output; //输出到文件的输出流 q3}WO]TBj  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =--oH'P=M  
public SiteFileFetch(SiteInfoBean bean) throws IOException x#c%+  
{ "1|\V.>>;  
siteInfoBean = bean; O"V;o
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nC(<eL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ge+T[  
if(tmpFile.exists ()) ibn(eu<uW  
{ M" R=;n  
bFirst = false; q!4eVg*  
read_nPos(); ;<N%D=;}@  
} $~r_&1  
else p`/c&}
 
{ L.
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nStartPos = new long[bean.getNSplitter()]; +\)a p  
nEndPos = new long[bean.getNSplitter()]; Y=\:fa  
} KuJNKuHa.  
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} Nn='9s9F?}  
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public void run() B&>z&!}  
{ %:e.E
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//获得文件长度 nN5fP<H2x  
//分割文件 .)Zs:50l  
//实例FileSplitterFetch Ci_Qra 6  
//启动FileSplitterFetch线程 E(g$f.9  
//等待子线程返回 /_qW?LKG/  
try{ W*r
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if(bFirst) gAr=fq-|  
{ ]8/g[Ii  
nFileLength = getFileSize(); Q:U>nm>xA  
if(nFileLength == -1) hI 1or4V  
{ Yaj}_M-  
System.err.println("File Length is not known!"); =:BTv[lv  
} zyP9 n[eZ  
else if(nFileLength == -2) &>P<Zw-  
{ +=K =B  
System.err.println("File is not access!"); \-8S"  
} kwUy^"O  
else w0^}c8%WR  
{ L L? .E  
for(int i=0;i<nStartPos.length;i++) )=
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{ yS1i$[JV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); YF)k0bu&;  
} apZPHau6h  
for(int i=0;i<nEndPos.length-1;i++) }inV)QQ  
{ =z[$o9  
nEndPos = nStartPos[i+1]; %U6A"?To  
} 2{<o1x,Ym  
nEndPos[nEndPos.length-1] = nFileLength; \![ p-mW{  
} l1vI  
} DR7JEE  
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i ?PgYk&}  
//启动子线程 :}z`4S@b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JFFluL=-  
for(int i=0;i<nStartPos.length;i++) otbr8&?-  
{ nzU;Bi^m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j]C}S*`"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QJ+Ml  
nStartPos,nEndPos,i); 1pAcaJzf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M $f6.j  
fileSplitterFetch.start(); +Jh1D_+!9  
} N}>[To3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2Q5-.2]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8]D0)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P^AI*tH"m  
nEndPos = " + nFileLength); 1gQ_76Yck  
// fileSplitterFetch[nPos.length-1].start(); -9Dr;2\  
:!Nx'F9a  
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//等待子线程结束 c9
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//int count = 0; r @}N6U~*  
//是否结束while循环 !e:_$$j  
boolean breakWhile = false; Qk >
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WPAT\Al&AE  
while(!bStop) \/64Xv3L0  
{ td7Of(k'  
write_nPos(); +)LCYDRV7  
Utility.sleep(500); Fw:_O2  
breakWhile = true; d$"?8r4:K  
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for(int i=0;i<nStartPos.length;i++) [bw1!X3  
{ \)?+6D'#  
if(!fileSplitterFetch.bDownOver) )-0+O=v  
{ ] n\]ao  
breakWhile = false; 3N5@<
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break; }?o4MiLB  
} '{-Ic?F<P  
} EJ(36h  
if(breakWhile) T%Bz>K  
break; .yDGwLry  
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1R;@v3  
//count++; 1nw\?r2  
//if(count>4) NcBz("  
// siteStop(); 4/%Y@Z5
 
} zf&:@P{  
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CF 3V)3}  
System.err.println("文件下载结束！"); )|_L?q#w!'  
} a?yU;IKJ  
catch(Exception e){e.printStackTrace ();} {1qr6P,"  
} 1[J|AkN  
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//获得文件长度 ,Js-'vX  
public long getFileSize() % m"Qg<  
{ F]t=5 -O<  
int nFileLength = -1; +u&[ j/  
try{ Paeq  
URL url = new URL(siteInfoBean.getSSiteURL()); s/.P/g%tA>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N6v?Qzvi  
httpConnection.setRequestProperty("User-Agent","NetFox"); cg o  
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int responseCode=httpConnection.getResponseCode(); J?EDz,  
if(responseCode>=400) 8t. QFze?  
{ I&m' a  
processErrorCode(responseCode); vw4b@v-XQ3  
return -2; //-2 represent access is error _-3n'i8  
} 4$WR8  
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String sHeader; \Z,{De%  
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for(int i=1;;i++) Rj4C-X4=  
{ M
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -Lu&bVt<>  
//Utility.log(in.readLine()); T9XUNR{&  
sHeader=httpConnection.getHeaderFieldKey(i); .xuzu#-  
if(sHeader!=null) jRd$Vt  
{ /&<V5?1|  
if(sHeader.equals("Content-Length")) !/!ga)Y  
{ PR]b]=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wa7wV 9  
break; SZyORN  
} N#ZWW6  
} -U\'Emu4  
else %<x!mE x  
break; %1$#fxR  
} 6M.|W;  
} \=7jp|{Yl  
catch(IOException e){e.printStackTrace ();} cdh0b7tjn  
catch(Exception e){e.printStackTrace ();} r~2hTie  
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Utility.log(nFileLength); d$n31F  
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return nFileLength; "TJ*mN.i{}  
} mLpM8~L  
m./PRV1$x  
-fl6M-CYX  
//保存下载信息（文件指针位置） ,oh;(|=  
private void write_nPos() {?5iK1|}K  
{ vsZ?cd
 
try{ }{VOyPG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \Dy|}LE  
output.writeInt(nStartPos.length); A+gS'DZ9C  
for(int i=0;i<nStartPos.length;i++) -F[@)$L  
{ `:;q4zij;  
// output.writeLong(nPos); E_aBDiyDf  
output.writeLong(fileSplitterFetch.nStartPos); Y*PfU+y~  
output.writeLong(fileSplitterFetch.nEndPos); ~mARgv  
} AB`.K{h  
output.close(); !{(Bc8 hT  
} CUYA:R<)  
catch(IOException e){e.printStackTrace ();} 3V?x&qlP>  
catch(Exception e){e.printStackTrace ();} J-Tiwl  
} Zi.
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//读取保存的下载信息（文件指针位置） qSB&Q0T  
private void read_nPos() J (?qk  
{ (nt`8 0  
try{ I](a 5i  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C[G+SA1&W  
int nCount = input.readInt(); UUlz3"`  
nStartPos = new long[nCount]; @anjjC5a~  
nEndPos = new long[nCount]; &v0-$  
for(int i=0;i<nStartPos.length;i++) m;]wKd"  
{ M@{#yEP  
nStartPos = input.readLong(); P|bow+4  
nEndPos = input.readLong(); -]HZ?@  
} n)98NSVDbT  
input.close(); HyU:BW;  
} rO$pj~!|Q  
catch(IOException e){e.printStackTrace ();} ?nGiif  
catch(Exception e){e.printStackTrace ();} ;6Yg}L  
} LCH\;07V#  
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v={{$=/t  
private void processErrorCode(int nErrorCode) KDq="=q  
{ o~IAZU39  
System.err.println("Error Code : " + nErrorCode); nYjrEy)Q  
} e))L&s  
#%\0][Xf  
{9U!0h-2"  
//停止文件下载 fk5'v
 
public void siteStop() 3WJk04r  
{ #mw!_]  
bStop = true; @m9pb+=v  
for(int i=0;i<nStartPos.length;i++) q\?s<l63  
fileSplitterFetch.splitterStop(); {g<D:"Q  
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} QMsq4yJ)%  
} fUkqhqe  
//负责部分文件的抓取 L^ J|cgmNw  
**FileSplitterFetch.java w3(|A> s3  
*/ q[a\a7U z  
package NetFox; ],pB:=  
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import java.io.*; heCM+=#~  
import java.net.*; 1N8] ~j  
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public class FileSplitterFetch extends Thread { *9EwZwE_K  
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String sURL; //File URL i D IY|  
long nStartPos; //File Snippet Start Position tF`L]1r>  
long nEndPos; //File Snippet End Position F,wB6Cw  
int nThreadID; //Thread's ID 'F/oR/4,  
boolean bDownOver = false; //Downing is over v'@gU
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boolean bStop = false; //Stop identical _xaum  
FileAccessI fileAccessI = null; //File Access interface ]- 1(r,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #&}- q RA  
{ CUI3^;&S  
this.sURL = sURL; {5E8eQ  
this.nStartPos = nStart; J[ Gpd  
this.nEndPos = nEnd; q!z"YpYB  
nThreadID = id; S{+t>en  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lPR=C0h}@  
} szsVk#p  
9&eY<'MgP  
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public void run() @.eN+o9|  
{ ?$f.[;mh  
while(nStartPos < nEndPos && !bStop) 4H-eFs%5  
{ yxt"vm;  
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try{ Y\]ZIvTSb  
URL url = new URL(sURL); )}@D\(/@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~v;I>ij  
httpConnection.setRequestProperty("User-Agent","NetFox"); cAW}a  
String sProperty = "bytes="+nStartPos+"-"; Vke<; k-  
httpConnection.setRequestProperty("RANGE",sProperty); *(OG+OkC  
Utility.log(sProperty); *#Cx-J  
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InputStream input = httpConnection.getInputStream(); fs'SCwx  
//logResponseHead(httpConnection); 6dIPgie3w  
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byte[] b = new byte[1024]; e"S?qpJK  
int nRead; P51M?3&=l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I`V<Sh^Qd  
{ ccag8LC  
nStartPos += fileAccessI.write(b,0,nRead); %;'~TtW5  
//if(nThreadID == 1) t`Z'TqP R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %GhI0F #  
} 1Toiqb/  
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Utility.log("Thread " + nThreadID + " is over!"); 8_('[89m  
bDownOver = true; O k`}\NZL  
//nPos = fileAccessI.write (b,0,nRead); yJ $6vmQ  
} ^^N|:80  
catch(Exception e){e.printStackTrace ();} Jl~ *@0(  
} ( eTrqI`  
} WywS1viD  
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*:n~j9V-  
//打印回应的头信息 {rKC4:  
public void logResponseHead(HttpURLConnection con) h3
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{ fN&\8SPE  
for(int i=1;;i++) /+Z*)q+SbT  
{ &u>dKf)5  
String header=con.getHeaderFieldKey(i); 3a?-UT!  
if(header!=null) -l= 4{^pK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w|9 >4  
Utility.log(header+" : "+con.getHeaderField(header)); "2cOSPpQL  
else F
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break; $tmdE)"&  
} 7iP+!e}$.  
} o}rG:rhIh  
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public void splitterStop() |R}=HsYey  
{ >w S'z]T9  
bStop = true; k>($[;k|b  
} Ehx9-*]
 
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} U~x]2{}  
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/* _,J+b R+b  
**FileAccess.java |MwV4^  
*//文件访问(定位，写) I1<WHq  
package NetFox; 2ioHhcYdJU  
import java.io.*; ~>CvZ7K  
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public class FileAccessI implements Serializable{ *[[Gu^t^!  
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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 E4X6f  
RandomAccessFile oSavedFile; LikcW#  
long nPos; @2>UR9j  
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public FileAccessI() throws IOException b84
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{ yvd)pH<a2  
this("",0); 5BVvT `<  
} [^qT?se{  
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public FileAccessI(String sName,long nPos) throws IOException T9nb ~P[  
{ ? :H+j6+f  
oSavedFile = new RandomAccessFile(sName,"rw"); jK w 96  
this.nPos = nPos; }+@9[Q L  
oSavedFile.seek(nPos); b80#75Bj>  
} |}=eY?iXo  
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public synchronized int write(byte[] b,int nStart,int nLen) =CLPz8  
{ Geq]wv8  
int n = -1; l2 .S^S  
try{ `2.c=,S{  
oSavedFile.write(b,nStart,nLen); 1VJ${\H]  
n = nLen; 5u!\c(TJ+  
} c*IrZm
  
catch(IOException e) Pq /5Dy  
{ (0 T!-hsP  
e.printStackTrace (); \L Q+ n+  
} _C !i(z!d  
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return n; 37hdZt.,  
} a-NTA  
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} 7e"}ojt$  
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/* Q#eMwM#~  
**SiteInfoBean.java T[\1=h]  
*/ &L8RLSfX  
package NetFox; t13V>9to  
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public class SiteInfoBean { `5Y*) q  
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private String sSiteURL; //Site's URL bmG`:_  
private String sFilePath; //Saved File's Path z CLaHx!  
private String sFileName; //Saved File's Name  t`o"K  
private int nSplitter; //Count of Splited Downloading File $_.t'8F  
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b| L;*<KU  
public SiteInfoBean() s#X/ F  
{//nSplitter的缺省值为5 EFX2>&mWo8  
//default value of nSplitter is 5 [q9B"@X  
this("","","",5); 0*{(R#  
} \YvG+7a  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &N}"4  
{ e9LX0=  
sSiteURL= sURL; Ln>!4i+-B)  
sFilePath = sPath; -@>{q/  
sFileName = sName; i2<z"v63  
this.nSplitter = nSpiltter; u&zY>'}zm  
5 ^{~xOM5  
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} R$&;  
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public String getSSiteURL() Fd9[Pe@?`  
{ Ud/>oaW?s  
return sSiteURL; 3%POTAw%  
} Y|tHU'x  
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public void setSSiteURL(String value) _}R$h=YD  
{ R~g|w4a@sC  
sSiteURL = value; lSX1|,B7:]  
} L.;b(bFe  
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public String getSFilePath() m212 gc0u  
{ vXKL<  
return sFilePath; p(yv  
} tD8fSV  
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2!%)_<  
public void setSFilePath(String value) 3bRxV @0.  
{ Gk:fw#R  
sFilePath = value; NM. e4  
} FvsVfV U  
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public String getSFileName() 4%0s p  
{ O=Su E/q  
return sFileName; ucl001EK  
} S m(*<H  
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public void setSFileName(String value) *BKD5EwS  
{ {K|?i9K  
sFileName = value;
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} m>uG{4<-  
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public int getNSplitter() bm#5bhX\|  
{ 8^_:9&)i  
return nSplitter; 7C|AiSH  
} l!p`g>$&f  
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public void setNSplitter(int nCount) YnpN -Y%g  
{ o)I)I/v  
nSplitter = nCount; YJ~<pH  
} H;`F}qQ3  
} l,|Llb  
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/* Fo3*PcUv  
**Utility.java *~8F.c
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*/ O?vh]o  
package NetFox; Z}O]pm>=G  
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public class Utility { O>)eir7  
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public Utility() 0
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{ +s#%\:Y M  
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} SGKAx<U  
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//线程睡眠  %lj5Olj  
public static void sleep(int nSecond) s_ZPo6p  
{ ~ZafTCa;  
try{ wH"9N+82M  
Thread.sleep(nSecond); 8L[+$g`  
} yu_PZ"l  
catch(Exception e) E$%v);u  
{ /Am9w$_T[  
e.printStackTrace (); rl.K{Uad  
} | V(sCF  
} M8H hjoo  
59nRk}^$se  
//日志 ]*NYuEgc  
public static void log(String sMsg) i&DbZ=n2  
{ 72$S'O%,0  
System.err.println(sMsg); 1V,@uY)s  
} .]>Tj^1  
7#JnQ| ]  
#JYl%=#,  
public static void log(int sMsg) @>2]zMFf  
{ :s_o'8z7L  
System.err.println(sMsg); "e-z2G@z  
} knO X5UnS  
} gb,ZN^3<-  
ltOS()[X  
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/* P 0\`4Cr!  
**TestMethod.java !$n@:W/  
*/ bofI0f}5.  
package NetFox;
TqJ @l  
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public class TestMethod { ,?LE5]  
+~=a$xA[C  
jA"}\^%3  
public TestMethod() '$,yV f  
{ ///xx/weblogic60b2_win.exe NioqJG?p  
try{ h`U-{VIrqi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7bYwh8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9o,Eqx4J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R.i]6H!  
fileFetch.start(); w*{{bISw|  
} W$]qo|2P  
catch(Exception e){e.printStackTrace ();} 09McUR@  
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} uWx<J3~q.  
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public static void main(String[] args) TQb/lY9*  
{ <5L99<E  
new TestMethod(); 'LoWp} f9  
} l!gX-U%-  
}
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