http断点续传简单实现（java)

/* M^madx6`  
**SiteFileFetch.java ]> !<G8=N  
*/ }ynT2a#LU'  
package NetFox; E8}+k o  
import java.io.*; b!>\2DlyJ  
import java.net.*; .w? .ib(  
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public class SiteFileFetch extends Thread { U
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;GHvPQc_  
long[] nStartPos; //开始位置 "E=j|q  
long[] nEndPos; //结束位置 Pt< s* (  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 JcO08
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long nFileLength; //文件长度 B/uniR^x  
boolean bFirst = true; //是否第一次取文件 w
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boolean bStop = false; //停止标志 )hKS0`$|  
File tmpFile; //文件下载的临时信息 GJ(d
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DataOutputStream output; //输出到文件的输出流 CZ{k@z
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XR+3j/zEQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException J]/}ojW3  
{ <&!]K?Q9i  
siteInfoBean = bean; lT8\}hNI+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E">T*ao  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L):U"M>]=  
if(tmpFile.exists ()) =v6*|  
{ {y^3> 7  
bFirst = false; yl]FP@N(  
read_nPos(); 2YwVU.*>  
} y>VcgLIB  
else do/)~9[4\  
{ "E!mva*NU  
nStartPos = new long[bean.getNSplitter()]; N1EezC'^  
nEndPos = new long[bean.getNSplitter()]; f`<FT'A  
} M@UVpQwgv  
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;.
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} $\
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public void run() |VH!)vD  
{ !|wzf+V  
//获得文件长度 eOlKbJU  
//分割文件 (il0M=M  
//实例FileSplitterFetch tOdT[&  
//启动FileSplitterFetch线程 /ONV5IkPy  
//等待子线程返回 :Waox"#=g  
try{ !3&kQpF  
if(bFirst) 8|1^|B(l  
{ 8s}J!/2  
nFileLength = getFileSize(); zi]%Zp  
if(nFileLength == -1) jh ez  
{ =ZYThfAEw  
System.err.println("File Length is not known!"); N"5fmY<  
} +54aO  
else if(nFileLength == -2) VkmRh,T  
{ D@Da0  
System.err.println("File is not access!"); 8pZ<9t'  
} t@zdm
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else 'w/qcD-  
{ "`tX
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for(int i=0;i<nStartPos.length;i++) 0Dv JZ|e  
{ Jcf"#u-Q/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P8yIegPY  
} n
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for(int i=0;i<nEndPos.length-1;i++) C"<s/
h  
{ TvhJVVQ+?  
nEndPos = nStartPos[i+1]; N0TeqOi4Y  
} Iq5pAHm>M6  
nEndPos[nEndPos.length-1] = nFileLength; b}
z
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} .#6MQJ]OH  
} RNJFSD.  
NC23Z0y  
'%iPVHK7  
//启动子线程 )6oGF>
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +",S2Qmo  
for(int i=0;i<nStartPos.length;i++) {5Lj8N5  
{ (
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @M;(K<%h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [uuj?Rbd
 
nStartPos,nEndPos,i); s'I)A^i+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |WqOk~)[Z3  
fileSplitterFetch.start(); *dE^-dm#  
} ?H|T&66  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ggm` ~fS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -$8.3\6h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L_O$>c  
nEndPos = " + nFileLength); 3fS}:!sQ
 
// fileSplitterFetch[nPos.length-1].start(); mX# "+X|  
6Z:YT&,f  
Y>6.t"?Q^  
//等待子线程结束 $n=lsDnhQ  
//int count = 0; {")\0|2\x  
//是否结束while循环 mB55PYA  
boolean breakWhile = false; 3Kq`<B~%  
nS.G~c|  
/MTf0^9  
while(!bStop) Fe=8O ^\  
{ 9M$/=>^ Z  
write_nPos(); @s*,xHE  
Utility.sleep(500); db
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breakWhile = true; c$M%G)P  
/Bv#) -5  
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for(int i=0;i<nStartPos.length;i++) t%0?N<9YkU  
{ C".1+Um  
if(!fileSplitterFetch.bDownOver) S'i;xL>  
{ ? 5|/ C  
breakWhile = false; 2ypIq
  
break; ISqfU]>[  
} $ @1u+w  
} ZW4aY}~)$  
if(breakWhile) mf$j03tu  
break; YcM;S  
t 0O4GcAN  
L4'[XcY  
//count++; L10IF  
//if(count>4) d"<F!?8  
// siteStop(); [s6C ZcL  
} 7!4V>O8@  
>.%4~\U  
1=GI&f2I  
System.err.println("文件下载结束！"); kA?_%fi1  
} aq>?vti1D  
catch(Exception e){e.printStackTrace ();} M@7Xp)S"  
} Ej
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@'jfKW  
//获得文件长度 "~+.Af  
public long getFileSize() :hqZPajE  
{ V0i9DK|!  
int nFileLength = -1; G?)vWM`j  
try{ a|qsQ'1,;  
URL url = new URL(siteInfoBean.getSSiteURL()); MK$Jj"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .KA V)So"  
httpConnection.setRequestProperty("User-Agent","NetFox"); |ng%PQq)  
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int responseCode=httpConnection.getResponseCode(); BWK IbG  
if(responseCode>=400) Wr%7~y*K  
{ I48VNX  
processErrorCode(responseCode); ,@CfVQz  
return -2; //-2 represent access is error LJuW${Y  
} 8C&x MA^  
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lgD]{\O$ip  
String sHeader; &d^=siL  
%$X\"  
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for(int i=1;;i++) qd2xb8r  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pM$ @m]  
//Utility.log(in.readLine()); @p!Q1-]=  
sHeader=httpConnection.getHeaderFieldKey(i); X>,A  
if(sHeader!=null) ZwJciT!_~  
{ sBW3{uK  
if(sHeader.equals("Content-Length")) ;;#nV$  
{ o0Gx%99'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;sQbn|=e"  
break; @EZ>f5IO+  
} ([pSVOnIz  
} o
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else ~<O,Vs_C/  
break; \+B?}P8N*l  
} JZx%J)  
} GW m4~]0E  
catch(IOException e){e.printStackTrace ();} l)Mh2lA,=  
catch(Exception e){e.printStackTrace ();} P[i
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Utility.log(nFileLength); `BT^a =5  
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return nFileLength; RaNeZhF>M  
} Q"}s>]k3_  
L3c*LL  
19I:%$U3  
//保存下载信息（文件指针位置） ^Q2ZqAf^a  
private void write_nPos() x:-`o_Q*i  
{ (V9h2g&8L  
try{ ixI:@#5wY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Slx2z%'>  
output.writeInt(nStartPos.length); r*d Q5 _  
for(int i=0;i<nStartPos.length;i++) ,U=E[X=
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{ myvh@@N  
// output.writeLong(nPos); ]N}]d +^6  
output.writeLong(fileSplitterFetch.nStartPos); Q_}n%P:u  
output.writeLong(fileSplitterFetch.nEndPos); " i`8l.Lc  
} ^ KOzCLC  
output.close(); 9q|7<raS  
} 'lQ
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catch(IOException e){e.printStackTrace ();} ~ x`7)3  
catch(Exception e){e.printStackTrace ();} vInFo.e[4  
} m5gI~1(9
 
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//读取保存的下载信息（文件指针位置） TzF0/T!  
private void read_nPos() *.8:'F  
{ wZ>Y<0,  
try{ M&e8zS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EAyukM2  
int nCount = input.readInt(); yQ-hnlzn~  
nStartPos = new long[nCount]; Wo3'd|Y~i  
nEndPos = new long[nCount]; n~%}Z[5D  
for(int i=0;i<nStartPos.length;i++) !sK#zAR2  
{ DQ_ 2fX~)  
nStartPos = input.readLong(); !R{em48D  
nEndPos = input.readLong(); r$DZkMue  
} BE4\U_]a3  
input.close(); x5vzPh`  
} uBRw>"c_*8  
catch(IOException e){e.printStackTrace ();} EXHR(t}e  
catch(Exception e){e.printStackTrace ();} C'<'7g4  
} _3&/(B%H  
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private void processErrorCode(int nErrorCode) ~XQ$aRl&  
{ NcM3P 
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System.err.println("Error Code : " + nErrorCode); XGk}e4;_  
} Fwv\pJ}$  
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nKu(XgFv  
//停止文件下载 %8<2>  
public void siteStop() ;MZbL)  
{ 1.dX)^\  
bStop = true; 1^sbT[%R  
for(int i=0;i<nStartPos.length;i++) I~k=3,7<  
fileSplitterFetch.splitterStop(); yk#rd~2
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} %*p^$5L<  
} S)Mby  
//负责部分文件的抓取 Ij,Yuo  
**FileSplitterFetch.java I+~\ w N  
*/ ?o>6S EGW  
package NetFox; k(9s+0qe  
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import java.io.*; )<Ob  
import java.net.*; |VYr=hjo  
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public class FileSplitterFetch extends Thread { 4w9F+*-  
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String sURL; //File URL %&2B  
long nStartPos; //File Snippet Start Position v?{vg?vI  
long nEndPos; //File Snippet End Position 2;}xN!8  
int nThreadID; //Thread's ID (xQI($Wq*M  
boolean bDownOver = false; //Downing is over fv/v|  
boolean bStop = false; //Stop identical -s33m]a;  
FileAccessI fileAccessI = null; //File Access interface D:6N9POB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R/rcXX7%  
{ ]3 j[3'  
this.sURL = sURL; qw)Key  
this.nStartPos = nStart; %0 qc@4  
this.nEndPos = nEnd; P;>!wU~*  
nThreadID = id; 8nf4Jk8r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \`&xprqAw  
} kp.|gzA6  
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public void run() IY~ {)X  
{ $Uy#/MX  
while(nStartPos < nEndPos && !bStop) H!#5!m&  
{ sB8p( L  
%'kX"}N/  
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try{ +O,V6XRr  
URL url = new URL(sURL); Ho>p ^p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QdirE4W  
httpConnection.setRequestProperty("User-Agent","NetFox"); x6j
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String sProperty = "bytes="+nStartPos+"-"; 35}P0+  
httpConnection.setRequestProperty("RANGE",sProperty); 6\XP|n-0+0  
Utility.log(sProperty); WEps.]s  
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InputStream input = httpConnection.getInputStream(); )v};C<  
//logResponseHead(httpConnection); %{Xm5#
m  
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byte[] b = new byte[1024]; -z&9DWH  
int nRead; 83B\+]{hD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;+r0 O0;9  
{ rrbZ+*U  
nStartPos += fileAccessI.write(b,0,nRead); Re7{[*Q4  
//if(nThreadID == 1) ]m RF[b$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Fu#Y7)r  
} [;Vi~$p|Eo  
(tTLK0V-|3  
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Utility.log("Thread " + nThreadID + " is over!"); )!BB/'DRQ  
bDownOver = true; gca|
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//nPos = fileAccessI.write (b,0,nRead); s!bHS_\e|  
} Q4#\{" N!  
catch(Exception e){e.printStackTrace ();} #T Z!#,q  
} 7%W!k zp>  
} zkH<aLRB  
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//打印回应的头信息 9'D8[p%  
public void logResponseHead(HttpURLConnection con) KX]-ll  
{ zj%c
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for(int i=1;;i++) 9]"\"ka3>  
{ bx1G CD  
String header=con.getHeaderFieldKey(i); H+nr5!`kz  
if(header!=null) Z=0iPy,m>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {|G&W^`  
Utility.log(header+" : "+con.getHeaderField(header)); )x y9X0  
else ?exALv'B  
break; ><MGZ?-N  
} "pR $cS  
} <<i=+ed8eP  
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public void splitterStop() hU |LFjc  
{ Mf!owpW T  
bStop = true; ,^Ex}Z  
} ))c*_n  
bBd*}"v^"  
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}
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/* Z?5,cI[6#  
**FileAccess.java u!sSgx=  
*//文件访问(定位，写) M|5^':Y  
package NetFox; ^w.k^U=B  
import java.io.*; SZN
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public class FileAccessI implements Serializable{ xKRfl1  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KB$ vQ@N  
RandomAccessFile oSavedFile; ;""-[4C  
long nPos; = .fc"R|<K  
8f5%xY$  
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public FileAccessI() throws IOException \UVT_=Y  
{ F0DPS:c  
this("",0); b#bO=T$e-  
} 89 _&X[X  
#MmmwPB_  
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public FileAccessI(String sName,long nPos) throws IOException 1',+&2)oj  
{ k i~Raa/e  
oSavedFile = new RandomAccessFile(sName,"rw"); ":5~L9&G  
this.nPos = nPos; j(wY/Hl  
oSavedFile.seek(nPos); "Wzij&WkQ  
} Z3&XTsq  
T#ecLD#  
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public synchronized int write(byte[] b,int nStart,int nLen) mE)x7  
{ M$DwQ}Z  
int n = -1; 1K
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try{ -Hl\j(D7  
oSavedFile.write(b,nStart,nLen); pZNlcB[Qn-  
n = nLen; 9&?tQ"@x  
} KyVe0>{_u  
catch(IOException e) &@Ji+  
{ 'eTpcrS3  
e.printStackTrace (); dA3`b*nC  
} /jn:e"0~  
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return n; \H}@-*z+)  
} #CBo  
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} @5uyUSt]  
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:{e`$kz  
/* tFb|y+  
**SiteInfoBean.java 2l;ge>DJ  
*/ L
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package NetFox; >xk:pL*o`  
IrVM|8vT3  
5wVi{P5+  
public class SiteInfoBean { _ ;v_L  
>Kqj{/SWK  
J[Ylo&w3  
private String sSiteURL; //Site's URL 0.3[=a43  
private String sFilePath; //Saved File's Path |$i1]Dr6  
private String sFileName; //Saved File's Name dRarNW  
private int nSplitter; //Count of Splited Downloading File `\}zm~  
)xXrs^  
./z"P]$
 
public SiteInfoBean() ]MBJ"1F  
{//nSplitter的缺省值为5 TO8\4p*tE  
//default value of nSplitter is 5 P7^TRrMF  
this("","","",5); iz$v8;w  
} 4%W
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NC#kI3{  
{ 2T{-J!k  
sSiteURL= sURL; 0bRkC,N (  
sFilePath = sPath; q,19NZ  
sFileName = sName; |R|U z`  
this.nSplitter = nSpiltter; a|^-z|.  
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LP-KD  
} Qc)RrqYNGF  
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public String getSSiteURL() ocuNrkZ  
{ -t706(#k  
return sSiteURL; +BTNm66Z  
} )l81R  
2+hfbFu,1  
Xj&~N;Ysb  
public void setSSiteURL(String value) ag*Hs<gi  
{ XzTH,7[n  
sSiteURL = value; =.3P)gY)  
} V-o`L`(F`  
-^NAHE$bW  
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public String getSFilePath() y*TNJJ|  
{ Z!BQtICs  
return sFilePath; kkuQ"^<J  
} 0OoO cc  
DG%%]  
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public void setSFilePath(String value) APOU&Wd  
{ \Q BpgMi(  
sFilePath = value; g{f>jd  
} [OToz~=)  
HZ`G)1&)  
5 <>agK]  
public String getSFileName() gpTF^.(  
{ 26klW:2*  
return sFileName; ?tM].\  
} DcvmeGl  
():?FJM  
,,-[P*@  
public void setSFileName(String value) 28L'7  
{ %l$&_xV
-  
sFileName = value; (YWc%f4  
} -X[8soz  
2wimP8  
kl<B*:RqH  
public int getNSplitter() R S_lQ{'  
{ I4DlEX  
return nSplitter; H<}Fk9  
} X9BBnZ  
J
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public void setNSplitter(int nCount) "a_D]D(d5  
{ i1H80m s  
nSplitter = nCount; UK9MWC5g9  
} :{='TMJ7  
} Q)i`.mHfFI  
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b.u8w2(  
/* 2ZIY{lBe  
**Utility.java jm!C
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*/ af5`ktx  
package NetFox; _=M'KCL*)  
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public class Utility { lM]),}   
u$ / ]59  
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public Utility() 4 ~|TKd{  
{ zbKW.u]v  
pD.@&J~  
-{sv3|P>  
} NqfDY  
*"bp}3$^^  
//线程睡眠 Y{:/vOj  
public static void sleep(int nSecond) [";5s&)q  
{ 7%x+7  
try{ "ddH7:(k<  
Thread.sleep(nSecond); $Lbe5d?\  
} 8qLgB   
catch(Exception e) _+Kt=;Y8  
{ 2g8P$+;  
e.printStackTrace (); `G5wiyH})  
} ;Z~.54Pf{d  
} YxqQg  
9@a;1Wr/f  
//日志 ~O7(0RsCN  
public static void log(String sMsg) ]6[d-$#^ko  
{ y!D`.'  
System.err.println(sMsg); -"tgEC\tD  
} PKs%-Uk  
e{+{,g{iu  
@BW8`Ky
1  
public static void log(int sMsg) =}KbE4D+8  
{ ~F6gF7]z  
System.err.println(sMsg); %hb5C 4q  
} RL)3k8pk  
} d*(\'6?  
"8 mulE,  
@{a-IW3  
/* _Cs}&Bic_  
**TestMethod.java T/6=A$4 #  
*/ "{xv|C<*n  
package NetFox;  ;I@L  
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(`Mz.VN  
public class TestMethod { ?YykCJJ ~@  
Cb-E<W&2D  
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public TestMethod() W)~.o/;  
{ ///xx/weblogic60b2_win.exe %$KO]   
try{ L=F
vLii.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); OYy !4Fp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'U0I.x(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F7l:*r,O  
fileFetch.start(); .*7UT~o=CS  
} OIT;fKl9  
catch(Exception e){e.printStackTrace ();} wdV?&W+  
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r  
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} ay|{!MkQ  
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public static void main(String[] args) )fL*Ws6  
{ o+Z9h1z%,  
new TestMethod(); iRtDZoiD'  
} zL}hFmh  
} 1y;zPJ<ntm  
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