http断点续传简单实现（java)

/* DOU?e9I2  
**SiteFileFetch.java V)jhyCL  
*/ @<JQn^M  
package NetFox; 4DM|OL`w  
import java.io.*; vrx3O  
import java.net.*; CnA)>4E*'  
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public class SiteFileFetch extends Thread { G"sc;nT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean > o`RPWs  
long[] nStartPos; //开始位置 @CUDD{1
o  
long[] nEndPos; //结束位置 <"%h1{V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %4K#<b"W  
long nFileLength; //文件长度 d/QM   
boolean bFirst = true; //是否第一次取文件 iPYlTV  
boolean bStop = false; //停止标志 wf$ JuHPt  
File tmpFile; //文件下载的临时信息 (W/UR9x)|d  
DataOutputStream output; //输出到文件的输出流 ,dMi+c`
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,R6$SrNcd  
public SiteFileFetch(SiteInfoBean bean) throws IOException (2)9TpE;  
{ ee` =B  
siteInfoBean = bean; <L#r6y~H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gcF><i6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x"De 9SB  
if(tmpFile.exists ()) K%Ml2V   
{ g<3>7&^  
bFirst = false; 9DKB+K.1  
read_nPos();
>;
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} <2A'   
else 7^X_tQf  
{ W4a20KM2  
nStartPos = new long[bean.getNSplitter()]; 9oz)E>K4f  
nEndPos = new long[bean.getNSplitter()]; K#m o+n5-;  
} nK=V`  
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} IDZn,^  
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public void run() X[6z  
{ aa]v7d  
//获得文件长度 JpiKZG@L  
//分割文件 U++UG5c  
//实例FileSplitterFetch wyM3|%RZ  
//启动FileSplitterFetch线程 d<e.`dhc  
//等待子线程返回 /V
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try{ D~>P/b)v{j  
if(bFirst) an~Kc!Oki  
{ KguFU  
nFileLength = getFileSize(); 4{E=wg^p  
if(nFileLength == -1) YdaJ&  
{ Vtri"G8 aB  
System.err.println("File Length is not known!"); (#k#0T kE  
} Pw{+7b$  
else if(nFileLength == -2) nfB9M1Svn  
{ hiuPvi}  
System.err.println("File is not access!"); R5zV=N  
}  f;a6ux#  
else U5=J;[w}N  
{ Ccmbdw,Z5  
for(int i=0;i<nStartPos.length;i++) [*v\X %+  
{ x #g,l2_!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q5JeL6t  
} +^:K#S9U  
for(int i=0;i<nEndPos.length-1;i++) 1cega1s3xR  
{ HR  
nEndPos = nStartPos[i+1]; ysPW<  
} 24fWj?A|^  
nEndPos[nEndPos.length-1] = nFileLength; 1<5yG7SZ  
} f^ qQ5N  
}
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oY:>pxSz<@  
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//启动子线程 ]W,g>91m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m\=u/Zip  
for(int i=0;i<nStartPos.length;i++) gE~31:a^  
{ !5-[kG&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V>Cf 8>m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LX'US-B.!  
nStartPos,nEndPos,i); $'Z!Y;Ue  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jL<.?HE  
fileSplitterFetch.start(); X(9Ff=0.~  
} 107SXYdhI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :nt%z0_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sMK/l @7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8:bNFgJD  
nEndPos = " + nFileLength); H Vy^^$  
// fileSplitterFetch[nPos.length-1].start(); >Ko )Z&j9W  
WjB[e>  
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//等待子线程结束 >KJ]\`2>)c  
//int count = 0; gMbvH
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//是否结束while循环 Z[VKB3Pb8  
boolean breakWhile = false; g@L4G?hLn  
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while(!bStop) 2_Qzc&"[ 4  
{ 2StpcAlU}  
write_nPos(); n_Z8%|h  
Utility.sleep(500);
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breakWhile = true; EMo6$(  
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>
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for(int i=0;i<nStartPos.length;i++) 6dh PqL  
{ Velm
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if(!fileSplitterFetch.bDownOver) ?l/rg6mbI'  
{ <~3 aaO  
breakWhile = false; KME #5=~  
break; ;S7xJ'H  
} ntT|G0E  
} +J} 41  
if(breakWhile) E9i WGSE  
break; x9=lN^/4  
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//count++; ?cJ$=  
//if(count>4) jL# akV  
// siteStop(); fITml6mbE  
} Vswi /(  
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System.err.println("文件下载结束！"); U6Qeode  
} =cQwR:):  
catch(Exception e){e.printStackTrace ();} ATU@5,9  
} 1\2 m'o  
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//获得文件长度 `C1LR,J  
public long getFileSize() R8E<;^?j  
{ L%DL n  
int nFileLength = -1; i0P+,U  
try{ hug12Cu  
URL url = new URL(siteInfoBean.getSSiteURL()); ,ZSuo4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r{btBv  
httpConnection.setRequestProperty("User-Agent","NetFox"); VYwaU^  
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int responseCode=httpConnection.getResponseCode(); +%yh@X6  
if(responseCode>=400) [Xrq+O,  
{ cE3co(j  
processErrorCode(responseCode); 5IepVS(>?v  
return -2; //-2 represent access is error (#:Si~3  
} ;9~z_orNQZ  
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String sHeader; e#seqx  
~ 0[K%]]  
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for(int i=1;;i++) IkvH8E  
{ (C
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); kxP6#8*:  
sHeader=httpConnection.getHeaderFieldKey(i); y
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if(sHeader!=null) jC oZm(bi  
{ M;E&@[5  
if(sHeader.equals("Content-Length")) > +SEze  
{ sOJ~PRA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [ /D/  
break; Kq*^*vWC  
} aH6pys!O  
} iPIA&)x}  
else wK3}K  
break; V*?,r<(  
} L/ZZe5I  
} #Ky0` n  
catch(IOException e){e.printStackTrace ();} |oM6(px  
catch(Exception e){e.printStackTrace ();} WRgz]=W3w  
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Utility.log(nFileLength); 1~*_H_Q't  
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return nFileLength; %6n;B|!  
} pp:+SoyN  
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//保存下载信息（文件指针位置） 1^,rS  
private void write_nPos() ,"/_G  
{ ] =D+a&  
try{ /; _"A)0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w8E,zH  
output.writeInt(nStartPos.length); 9> |rIw  
for(int i=0;i<nStartPos.length;i++) HG^8&uh]  
{ ^O?$}sr  
// output.writeLong(nPos); *D'VW{  
output.writeLong(fileSplitterFetch.nStartPos); $&4Zw6"=  
output.writeLong(fileSplitterFetch.nEndPos); U!Lws#\X  
} 0QPipuP  
output.close(); ed{9UJWh  
} >ko;CQR  
catch(IOException e){e.printStackTrace ();} ."lY>(HJ  
catch(Exception e){e.printStackTrace ();} ED6H  
} NZ_45/(dx  
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//读取保存的下载信息（文件指针位置） [;2v[&
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private void read_nPos() u66w('2  
{ xS.0u"[  
try{ u/MIB`@,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4uv }6&R  
int nCount = input.readInt(); &O'yhAP] j  
nStartPos = new long[nCount]; >):b AfI  
nEndPos = new long[nCount]; R38 w!6{  
for(int i=0;i<nStartPos.length;i++) l})uYae/  
{ n;MoMGnPh,  
nStartPos = input.readLong(); a5)+5  
nEndPos = input.readLong(); 2q#$?qs_b  
} Ft]sTA+
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input.close(); []Z6<rC|  
} 4jXyA/F9V  
catch(IOException e){e.printStackTrace ();} FPqgncBHK  
catch(Exception e){e.printStackTrace ();} $UH_)Q2#J^  
} BG|Kw)z*KM  
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private void processErrorCode(int nErrorCode) =#W{&Te;  
{ EH[?*>+s  
System.err.println("Error Code : " + nErrorCode); 9KP+  
} 1rN&Y,61\  
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7#RW4ZM  
//停止文件下载 Ghj6&K%b0  
public void siteStop() ,
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{ AXJC&O}`  
bStop = true; \UiuJ+  
for(int i=0;i<nStartPos.length;i++) H: U_k68  
fileSplitterFetch.splitterStop(); u_uC78`p  
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} B}3s=+L@8  
} @}[)uH  
//负责部分文件的抓取 u%T.XgY=j  
**FileSplitterFetch.java lr|-_snx2  
*/ 0 xXAhv-)O  
package NetFox; j\ )Qn2r  
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import java.io.*; Xc@4(Nyp  
import java.net.*; jHFdDw|N`  
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public class FileSplitterFetch extends Thread { B (BWdrG  
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String sURL; //File URL ZJx:?*0a  
long nStartPos; //File Snippet Start Position Q8P;AN_JS  
long nEndPos; //File Snippet End Position !?KY;3L:  
int nThreadID; //Thread's ID x|Q6[Y  
boolean bDownOver = false; //Downing is over 3Y=S^*ztd  
boolean bStop = false; //Stop identical Obw uyhjQ  
FileAccessI fileAccessI = null; //File Access interface =]D##R  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException & MAIm56~  
{ iA:CPBv_mu  
this.sURL = sURL; b)df V=  
this.nStartPos = nStart; $1w8GI\J  
this.nEndPos = nEnd; YT-t$QyL  
nThreadID = id; "=Ziy4V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J${wU@_%  
} *<9p88FpDU  
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public void run() +tuC845  
{ ljNd!RaB  
while(nStartPos < nEndPos && !bStop) a ZfX
|  
{ [@/G?sAQm\  
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try{ $bN%x/
  
URL url = new URL(sURL); / ]I]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z'u`)jR  
httpConnection.setRequestProperty("User-Agent","NetFox"); B^KC~W  
String sProperty = "bytes="+nStartPos+"-"; <yIJ$nBx  
httpConnection.setRequestProperty("RANGE",sProperty); WJ mj|$D  
Utility.log(sProperty); nc`[fy|}  
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InputStream input = httpConnection.getInputStream(); Zaq:l[%
 
//logResponseHead(httpConnection); @ws3X\`<C  
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byte[] b = new byte[1024]; LEk W^Mv  
int nRead; ^*Ca+22xO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yy%
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{ ql],Wplg  
nStartPos += fileAccessI.write(b,0,nRead); !QYqRH~5  
//if(nThreadID == 1) 0C0iAp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BB~Qs  
} Ha;^U/0|  
4$.4,4+  
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Utility.log("Thread " + nThreadID + " is over!"); 9=hA#t.#  
bDownOver = true; /*st,P$"  
//nPos = fileAccessI.write (b,0,nRead); }bHdU]$}  
} =_TCtH  
catch(Exception e){e.printStackTrace ();} l'$AmuGj  
} ^g
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} |JrG?:n  
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//打印回应的头信息 uYJ6"j  
public void logResponseHead(HttpURLConnection con) dGZVWEaPfx  
{ 'os-+m@  
for(int i=1;;i++) _sw,Y!x%dF  
{ \<V{6#Q=  
String header=con.getHeaderFieldKey(i); uTOL  
if(header!=null) .vwOp*3\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3dC8MKPq0  
Utility.log(header+" : "+con.getHeaderField(header));  M)Y`u  
else Ib]{rmaP  
break; 84|Hn|4t  
} D @T,j4o  
} #Mi>f4T;  
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public void splitterStop() b[H& vp  
{ 8r+R~{  
bStop = true; @|r*yi  
} Rh,*tS  
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} +xB!T1pD  
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/* t[7YMk  
**FileAccess.java <+C]^*j  
*//文件访问(定位，写) wB"&K;t  
package NetFox; 4km=KOx[  
import java.io.*; ~^:/t<N  
f |aO9w   
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public class FileAccessI implements Serializable{ |f.=Y~aY  
 Trm)7B*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?GX5Pvg
 
RandomAccessFile oSavedFile; |Q.t]TR'P  
long nPos; w#]%I+  
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public FileAccessI() throws IOException ^D"}OQoh  
{ ;,4Z5+  
this("",0); Rm"lRkY4I[  
} %0. o(U  
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public FileAccessI(String sName,long nPos) throws IOException OP%h`  
{ ;OE{&  
oSavedFile = new RandomAccessFile(sName,"rw"); NC|&7qQ  
this.nPos = nPos; |$^,e%bE  
oSavedFile.seek(nPos); 1u'x|Un  
} l8n#sGA%  
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public synchronized int write(byte[] b,int nStart,int nLen) RCnN+b:c  
{ ,RDxu7iT  
int n = -1;  E~jNUTq  
try{ =^O84Cp 6  
oSavedFile.write(b,nStart,nLen); 3]M YHb  
n = nLen; Hk(w\   
}  &EV|knW  
catch(IOException e) *ofK|r  
{ K-(,,wS  
e.printStackTrace (); "pQM$3n(  
} I Yj\t?,0  
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return n; _hK7hvM>  
} o~2bk<]z  
+.mIC:9  
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} L*Xn!d%  
e*:[#LJ]C  
@| qnD  
/* ')}$v+9h  
**SiteInfoBean.java 0A/GWSmF  
*/ >pT92VN  
package NetFox; S\MD]>4  
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<  
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public class SiteInfoBean { (+q?xwl!N  
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private String sSiteURL; //Site's URL LPvyfD;Zy  
private String sFilePath; //Saved File's Path *.~
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private String sFileName; //Saved File's Name )j]S;Mr  
private int nSplitter; //Count of Splited Downloading File 4cTJ$" v  
7a->"W  
76 #  
public SiteInfoBean() w[n|Sauy,  
{//nSplitter的缺省值为5 W9ZT=#>)[  
//default value of nSplitter is 5 qL,QsRwN  
this("","","",5); #}^
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} gh['T,  
 QSmE:Y  
*B#<5<T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5MO:hE5sm  
{ BAx)R6kS;  
sSiteURL= sURL; JOx75}  
sFilePath = sPath; fI t:eKHr  
sFileName = sName; s"=e(ob  
this.nSplitter = nSpiltter; \b1I<4(  
;yx+BaG~?  
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} -~p@o1k0  
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public String getSSiteURL() (IAl$IP63s  
{ k'xnl"q  
return sSiteURL; <xOpm8  
} 8L|rj4z<#  
7'xT)~*$4  
7"Zr:|$U  
public void setSSiteURL(String value) OHR9u  
{ V89!C?.[]1  
sSiteURL = value; 7Q/v#_e(  
} LGgEq-  
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public String getSFilePath() K/, B  
{ 7?]gUrE  
return sFilePath; jcYI"f"~  
} ;_F iiBk7(  
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public void setSFilePath(String value) tv,^ Q}  
{ YL;ZZ2A  
sFilePath = value; @lc1Ipfk"  
} Km'd=B>Jy  
VjMd&>G  
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public String getSFileName() .]k(7F!W  
{ %Jq(,u  
return sFileName; q}M^i7IE  
} bsR^H5O@  
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@433?g`2b  
public void setSFileName(String value) TXH: +mc  
{ #OJsu  
sFileName = value; SdYES5aES  
} ahhVl=9/ao  
49 fs$wr@  
^pKC0E[%  
public int getNSplitter() o{f n}  
{ X:j&+d2g0/  
return nSplitter; ?P4`  
} Y\%R6/Gj|u  
&+J5GHt@  
F<Z"W}I+6  
public void setNSplitter(int nCount) o//N"S.)  
{ kVe^g
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nSplitter = nCount; *O$kF.3q  
} @>ONp|}@qI  
} j0kEi+!TVq  
)d>"K`3  
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/* 4TGg`$e;  
**Utility.java 4Qz  
*/ -+'{C
=  
package NetFox; tqmM7$}}P  
s%H5Qa+Uh  
*NFy%ktu  
public class Utility { vJtQ&,zG  
VEwv22'  
<Zl0$~B:5  
public Utility() 7V 2%  
{ RVXRF_I  
C3G?dZKv2  
8ft
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} rQ30)5^V|  
:*/<eT_  
//线程睡眠 gG*O&gQY  
public static void sleep(int nSecond) p!hewtb5  
{ 85w D<bN27  
try{ |uj1T=ZY  
Thread.sleep(nSecond); DS=kSkW^&5  
} ~ Y4H)r  
catch(Exception e) h:
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{ 8p-5.GU)<e  
e.printStackTrace (); R+]Fh4t  
} U11rj,7  
} fR_)e:  
0 m";=:(w  
//日志 j<"0ym)A  
public static void log(String sMsg) (J\D"4q  
{ v~L} :  
System.err.println(sMsg); 8{4I6;e-  
} d,8V-Dk+p  
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3P^eD:) w  
public static void log(int sMsg) `i
f*  
{ D7sw;{n
s  
System.err.println(sMsg); I@pnZ-5  
} c?V,a`6  
} 44kY[jhf  
lY?TF  
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/* 87YT;Z;U&  
**TestMethod.java ?rk3oa-  
*/ unSF;S<  
package NetFox; Q\m"n^XN  
5NJ@mm{0  
>J.a,!  
public class TestMethod { wW6?.}2zU  
vkc(-n  
HR['y9U  
public TestMethod() qf4|!UR{  
{ ///xx/weblogic60b2_win.exe &7E0H{  
try{ Pkc4=i,`A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \8ulX>]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EpOVrk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6;*tw i  
fileFetch.start(); Wj8\~B=('  
} ]r'b(R; S  
catch(Exception e){e.printStackTrace ();} 68;,hS*|6  
x03GJy5  
Wq&TbWR  
} 3j]La  
P)(Ly5$*  
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public static void main(String[] args) kki]6_/n  
{ P:ys--$"  
new TestMethod(); *v8Cj(69  
} Fe"0Hp+  
} |+suGqo  
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