http断点续传简单实现（java)

/* 0At0`Q#  
**SiteFileFetch.java kAftW
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*/ XT7m3M  
package NetFox; Myq8`/_  
import java.io.*; DT-VxF6h  
import java.net.*; )6"}M;v  
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public class SiteFileFetch extends Thread { 2W AeSUX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #{i*9'  
long[] nStartPos; //开始位置 !_fDL6a-  
long[] nEndPos; //结束位置 WAu
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jf YgZ\#  
long nFileLength; //文件长度 Kz HYh  
boolean bFirst = true; //是否第一次取文件 lC<;Q*Y  
boolean bStop = false; //停止标志 'zyw-1  
File tmpFile; //文件下载的临时信息 }(EH5jZ'  
DataOutputStream output; //输出到文件的输出流 e3I""D{)[=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zsL@0]e&  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9+ 'i(q z  
{ rXx#<7`  
siteInfoBean = bean; ,\4]uZ<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6VW*8~~Xy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZW4
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if(tmpFile.exists ()) e~)[
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{ 8^7Oc,:~  
bFirst = false;
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read_nPos(); qng ~,m  
} a5*r1,  
else ImXYI7PL  
{ 4fLRl-)  
nStartPos = new long[bean.getNSplitter()]; \xYVnjG,  
nEndPos = new long[bean.getNSplitter()]; 4Aj~mA  
} dNACE*g;q  
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} +nYFLe  
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public void run() `v*HH}aDO  
{ 5`h$^l/  
//获得文件长度 lM-9J?j  
//分割文件 J%"BCbxW~B  
//实例FileSplitterFetch 0|&@)`  
//启动FileSplitterFetch线程 @MSmg3&  
//等待子线程返回 C- .;m  
try{ F#Lo^ 8  
if(bFirst) c^}y9% 4c  
{ 80lei  
nFileLength = getFileSize(); '*J+mZtN  
if(nFileLength == -1) ]!/
  
{ J0xHpe  
System.err.println("File Length is not known!"); qb>ULP0  
} r:*G{m-  
else if(nFileLength == -2) ON2o^-%=  
{ j=r1JV @  
System.err.println("File is not access!"); IeYYG^V<A  
} _ *f>UW*,  
else omE- c  
{ KC;cu%H  
for(int i=0;i<nStartPos.length;i++) I&-r^6Yx  
{ +_GS@)L`%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3^8Cc(bk  
} 4]o+)d.`(  
for(int i=0;i<nEndPos.length-1;i++) -.Wcz|  
{ W!{RJWe  
nEndPos = nStartPos[i+1]; -S$F\%  
} Xa`Q;J"h  
nEndPos[nEndPos.length-1] = nFileLength; 7^d
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} tZ_'>7)  
} ale'-V)5  
gd;!1GNi]  
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//启动子线程 8(1*,CJQg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sfF~
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for(int i=0;i<nStartPos.length;i++) $1yy;IyR  
{ G6p gG+w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {4J.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U1 _"D+XB  
nStartPos,nEndPos,i); VbX P7bZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .a4,Lr#q.  
fileSplitterFetch.start(); o[Ffa#sE  
} |A&;m}(Mt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Oe5rRQ$O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $d<NN2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >@vu;j\*E5  
nEndPos = " + nFileLength); h/EIFve  
// fileSplitterFetch[nPos.length-1].start(); EGXvz)y  
s~M$Wo8  
8~Cmn%  
//等待子线程结束 VYG@_fd!x  
//int count = 0; <6UXk[y  
//是否结束while循环 PUR,r%K`  
boolean breakWhile = false; uu6 JZp  
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}UPC~kC+Z  
while(!bStop) BUXE s0]Lv  
{ q T6y&  
write_nPos(); ZJDV'mC}  
Utility.sleep(500); q`xc h[H  
breakWhile = true; qo[[P)tq  
^4`aONydl  
#W~jQ5NS\  
for(int i=0;i<nStartPos.length;i++) sOhn@*X  
{ A5nggg4  
if(!fileSplitterFetch.bDownOver) u W]gBhO$O  
{ _vTr?jjfK  
breakWhile = false; 5r5on#
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break; T]th3*  
} a_b#hM/c;  
} Fb{N>*l.  
if(breakWhile) VrIN.x  
break; <^YvgQ,m  
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//count++; '{ <RX  
//if(count>4) x?S86,RW  
// siteStop(); 5*44QV  
}
|[`YGA4  
9]eG|LFD  
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System.err.println("文件下载结束！"); ;@Zuet  
} gTj,I=3$?e  
catch(Exception e){e.printStackTrace ();} ,p|Q/M^  
} ,U""m7   
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+La2-I  
//获得文件长度 Im6gWDdq@6  
public long getFileSize() , >7PG2 a  
{ 'g%:/lwA  
int nFileLength = -1; MT!Y!*-5  
try{ ,5W7a  
URL url = new URL(siteInfoBean.getSSiteURL()); 8?Rp2n*o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y8YsS4E^Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7Fj8Mp|  
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int responseCode=httpConnection.getResponseCode(); d*8*9CpO:  
if(responseCode>=400) ny KfM5s_  
{ Z@s[8wrmPl  
processErrorCode(responseCode); w"{DLN[Qw  
return -2; //-2 represent access is error Va )W[I  
} 6Z|h>H5a  
3dN`Q:1R9  
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String sHeader; 8i',~[  
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for(int i=1;;i++) lie,A  
{ f#z:ILG=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ch]d\GM  
//Utility.log(in.readLine()); +zh\W9  
sHeader=httpConnection.getHeaderFieldKey(i); ~cc }yDe  
if(sHeader!=null) lT
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{ PhyIea  
if(sHeader.equals("Content-Length")) 35l%iaj]G5  
{ /ZyMD(_J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]W;6gmV  
break; YYpC!)  
} 3CD#OCz7&  
} yeiIP  
else dFBFXy  
break; sFM$O232  
} z)M#9oAM  
} 'I>USl3hI  
catch(IOException e){e.printStackTrace ();} 9)wYSz'  
catch(Exception e){e.printStackTrace ();} sSU|N;"Y  
~61b^L}$  
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Utility.log(nFileLength); #@oB2%&X?  
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return nFileLength; t*hy"e{*a  
} \ ku5%y  
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//保存下载信息（文件指针位置） h^g0|p5  
private void write_nPos() j&X&&=   
{ R=~%kt_n  
try{ y"yo\IDW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UN'n~d@~  
output.writeInt(nStartPos.length); eA7 Iv{M  
for(int i=0;i<nStartPos.length;i++) !dT+cZsf  
{ @eJ8wf]  
// output.writeLong(nPos); a,Pw2Gcid  
output.writeLong(fileSplitterFetch.nStartPos); OMK,L:poC  
output.writeLong(fileSplitterFetch.nEndPos); JlYZ\  
} @<P2di  
output.close(); Ry
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} Po58@g  
catch(IOException e){e.printStackTrace ();} > -OOU  
catch(Exception e){e.printStackTrace ();} 6FzB-],  
} nG<oae6z"  
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SOI=~BGd)  
//读取保存的下载信息（文件指针位置） q;,lv3I  
private void read_nPos() bkd`7(r  
{ SE\?8cs]-  
try{ d3:GmB .  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,!_6X9N-h  
int nCount = input.readInt(); hdDT'+  
nStartPos = new long[nCount]; '4uu@?!dVk  
nEndPos = new long[nCount]; R%KF/1;/  
for(int i=0;i<nStartPos.length;i++) b*Y Wd3  
{ 'Ou C[$Z  
nStartPos = input.readLong(); .=;IdLO,Bf  
nEndPos = input.readLong(); %>$<s<y  
} bB?E(>N;  
input.close(); U>lf-iI2B  
} 8)>x)T  
catch(IOException e){e.printStackTrace ();} (T*$4KGV  
catch(Exception e){e.printStackTrace ();} OK]
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} 6C2~0b   
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private void processErrorCode(int nErrorCode) }`gOfj)?i  
{ KhND pwO"  
System.err.println("Error Code : " + nErrorCode); @$jV"Y  
} cTGd<  
%g@?.YxjT  
F6}RPk\=i  
//停止文件下载 t~(jA9n  
public void siteStop() $.vm n,:.  
{ nsI+04[F  
bStop = true; N[@H107`  
for(int i=0;i<nStartPos.length;i++) DURWE,W>  
fileSplitterFetch.splitterStop(); 8GP17j  
> T*`Y0P  
@[lMh9`  
} I]C
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} 3aq'JVq  
//负责部分文件的抓取 Z$/76  
**FileSplitterFetch.java 'TS_Am?o  
*/ iv>MIdIm  
package NetFox; 3A`Gx#  

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import java.io.*; 1<G+KC[F  
import java.net.*; }PJsPIa3j  
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6 ]x?2P%  
public class FileSplitterFetch extends Thread { .yy-jf/  
qA GjR!=^  
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String sURL; //File URL 74M9z  
long nStartPos; //File Snippet Start Position l$/pp  
long nEndPos; //File Snippet End Position 2yK">xYY@  
int nThreadID; //Thread's ID _94 W@dW  
boolean bDownOver = false; //Downing is over 1_TuA(  
boolean bStop = false; //Stop identical YHEn{z7  
FileAccessI fileAccessI = null; //File Access interface KZjh<sjX|  
*U^Y@""a  
j4owo#OB-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W#bYz{s.  
{ tle`O)&uo  
this.sURL = sURL; D[yyFo,z  
this.nStartPos = nStart; WrGA7&!+  
this.nEndPos = nEnd; Qel)%|dOn  
nThreadID = id; i"G'#n~e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?z1v_Jh  
} Oin9lg-jR  
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public void run() n- 2X?<_Z  
{ >IIq_6Z#  
while(nStartPos < nEndPos && !bStop) To*+Z3Wd  
{ fF)Q;~_VA  
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try{ AfA"QCyO  
URL url = new URL(sURL); T2Yf7Szp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4Et(3[P71  
httpConnection.setRequestProperty("User-Agent","NetFox"); a|FkU%sjzZ  
String sProperty = "bytes="+nStartPos+"-"; g.&B8e  
httpConnection.setRequestProperty("RANGE",sProperty); Q!P%duO  
Utility.log(sProperty); 6axxyh%  
{J==y;dK  
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InputStream input = httpConnection.getInputStream(); J|BElBY  
//logResponseHead(httpConnection); ^^V3nT2rR3  
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~Y/A]N86,  
byte[] b = new byte[1024];  tA#$q;S  
int nRead; *|=D 0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SxYz)aF~  
{ i]c{(gd`  
nStartPos += fileAccessI.write(b,0,nRead); Rv&"h_"t  
//if(nThreadID == 1) jg?UwR&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4

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} G^Gs/- f  
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Utility.log("Thread " + nThreadID + " is over!"); w80
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bDownOver = true; K(?V]Mxl6  
//nPos = fileAccessI.write (b,0,nRead); dq '2y  
} 9}6_B|  
catch(Exception e){e.printStackTrace ();} mEJ7e#  
} ]pvHsiI:  
} MZz9R*_VS  
]W?cy  
z}Cjk6z@  
//打印回应的头信息 @4;'>yr(  
public void logResponseHead(HttpURLConnection con) $L^%*DkM  
{ 5$=[x!x  
for(int i=1;;i++) tKt}]KHV  
{ ]00so`  
String header=con.getHeaderFieldKey(i); \$_02:#  
if(header!=null) Ln#o:"
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6!]@S|vDX  
Utility.log(header+" : "+con.getHeaderField(header)); @_C]5D^J^~  
else [^ }$u[  
break; TAUl{??,  
} fJ/INL   
} STwGp<8  
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public void splitterStop() pl>b 6 |  
{ OH>.N"IG  
bStop = true; 9^!.!%6O$  
} 9YI@c_1 Q  
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} QT+kCN  
US)i"l7:H*  
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/* %O9Wm_%  
**FileAccess.java ~S('\h)1  
*//文件访问(定位，写) ^Z)7Z% O  
package NetFox; W$jRS  
import java.io.*; `e ZDG  
~a_hOKU5  
m^oG9&";  
public class FileAccessI implements Serializable{ LhAN( [  
1vq2`lWpx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9C \}bT  
RandomAccessFile oSavedFile; ]lA}5  
long nPos; q%G
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public FileAccessI() throws IOException s#5#WNzP  
{ 1?QVtfwY  
this("",0); diNSF-wi,,  
} gN}$$vS  
<zqIq9}r  
)s>|;K{  
public FileAccessI(String sName,long nPos) throws IOException `mcb0  
{ Ei:m@}g  
oSavedFile = new RandomAccessFile(sName,"rw"); nN&dtjoF  
this.nPos = nPos; M;XU"8  
oSavedFile.seek(nPos); QyA^9@iVs  
} #Tc`W_-  
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public synchronized int write(byte[] b,int nStart,int nLen) J?{sTj"KB  
{ 9 5!xJdq  
int n = -1; 2
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try{ Q.$/I+&j  
oSavedFile.write(b,nStart,nLen); P>q
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n = nLen; U>kaQ54/  
} (A2ga):Pk  
catch(IOException e) jk`U7G*  
{ IsT}T}p,t  
e.printStackTrace (); Uhvy2}w  
} YN)qMI_`A  
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return n; 2.nT k  
} IgJG,!>h  
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} d0T 8Cwcb  
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jA^yUd-  
/* N#-%b"(  
**SiteInfoBean.java -5e8m4*
 
*/ L2Cb/!z`c  
package NetFox; 0>m$e(Z  
alRz@N  
v"2A?  
public class SiteInfoBean { MX*4d{l  
lre(]oBXA  
\=RV?mI3?  
private String sSiteURL; //Site's URL IV&5a]j  
private String sFilePath; //Saved File's Path :{eYm|2-  
private String sFileName; //Saved File's Name sz%]rN6$  
private int nSplitter; //Count of Splited Downloading File [GCaRk>b,  
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!|9@f$Jv  
public SiteInfoBean() 0xi2VN"X  
{//nSplitter的缺省值为5 `!X8Cn  
//default value of nSplitter is 5 
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this("","","",5); "$5cKbJ  
} QX?moW6UW  
r+Sv(KS4i^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Rex86!TO  
{ *B4OvHi)'  
sSiteURL= sURL; DQObHB8L  
sFilePath = sPath; = <A0;  
sFileName = sName; ~Q^.7.-T  
this.nSplitter = nSpiltter; hH$9GL{H  
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BSkmFd(*  
} Md9y:)P@Y  
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@@3NSKA  
public String getSSiteURL() $2]>{g  
{ t0<RtIh9e  
return sSiteURL; >t9
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} 2ETv H~23  
MYJMZ3qBi  
?W dY{;&  
public void setSSiteURL(String value) KWYjN h#*  
{ 3it*l-i\  
sSiteURL = value; ,y0 &E8Z  
} kxrYA|x  
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public String getSFilePath() (uHyWEHt  
{ _^?_Vb  
return sFilePath; nql{k/6  
} #$ka.Pj  
HOPl0fY$L  
6%9 kc+ 9  
public void setSFilePath(String value) ,<7HLV  
{ \ %xku:  
sFilePath = value; a$iDn_{  
} D0_CDdW%7  
=^zGn+@z  
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public String getSFileName() b5~p:f-&4B  
{ Z>/ *q2  
return sFileName; CZ^ ,bad  
} ]"O*&  
u!HbS*jqq  
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public void setSFileName(String value) h0x'QiCc  
{ Jz0AYiCq  
sFileName = value; FBrh!vQ<  
} 3k8nWT:wT  
<h|&7  
^;{uop"DS  
public int getNSplitter() Y#P!<Q>}  
{ P=P']\`p+  
return nSplitter; =~,2E;#X  
} ',D%,N}J  
h*hkl#  
h`vT[u~l  
public void setNSplitter(int nCount) @I&k|\  
{ gLFSZ  
nSplitter = nCount; mU[  
} [Ak
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} %LqT>HXJ  
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@tRDKPh  
/* 3C;;z  
**Utility.java 6xr%xk2E  
*/ :Ez*<;pF'  
package NetFox; }0/l48G  
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public class Utility { osO\ib_%  
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public Utility() M
4 }))  
{ 4UPxV"H  
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6#:V3 ;  
} j5smmtM`s  
Vvv;m5.  
//线程睡眠 Ofb&W AD  
public static void sleep(int nSecond) YoK )fh$  
{ 9B>P Qbs  
try{ }Q^*Zq9-  
Thread.sleep(nSecond); "2tKh!?Q  
} cUw$F{|W  
catch(Exception e) )RWY("SUy1  
{ ?oV|.LM:W  
e.printStackTrace (); &tiJ=;R1  
} Y!ypG-  
} 2PNe~9)*#  
{g4w[F!77  
//日志 ZBQ@S  
public static void log(String sMsg) 1bDXv,nD  
{ >C5u>@%
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System.err.println(sMsg); k|jr+hmn":  
} .WBp!*4  
v@fy*T\3  
cQ`0d3  
public static void log(int sMsg) (b1e!gJpy  
{ n0V^/j}  
System.err.println(sMsg); UuZjf9}  
} S*76V"")  
} OeZ"WO  
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W]>%*n  
/* iJKGzHvS  
**TestMethod.java UQP>yuSx  
*/ fL-$wK<p<  
package NetFox; Vhe$vH  
,sg\K>H=  
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public class TestMethod { P*ZMbAf.  
=L?2[a$2;  
93,7yZ5#  
public TestMethod() q(2ZJn13f  
{ ///xx/weblogic60b2_win.exe ?O]RQXsZ2  
try{ X]W(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uA t{WDHm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _ib @<%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AW!A+?F6  
fileFetch.start(); iG=Di)O  
} }{&;\^i  
catch(Exception e){e.printStackTrace ();} CHCT e  
[;~"ctf{  
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} *q[;-E(fZ#  
eq<!  
.Ep&O#  
public static void main(String[] args) E},zB*5TH  
{ |GP&!]  
new TestMethod(); 5-&"nn2*}1  
} b0x%#trA{  
} R. vV
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