http断点续传简单实现（java)

/* Jm3iYR+,  
**SiteFileFetch.java 3M[5_OK  
*/ ktiC*|fd  
package NetFox; K~ VUD(  
import java.io.*; _j?/O)M c  
import java.net.*; }>?"bcJ  
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public class SiteFileFetch extends Thread { aWMEo`O%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean AjMx\'(C  
long[] nStartPos; //开始位置 S*a_  
long[] nEndPos; //结束位置 $qk(yzY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CDGN}Q2_  
long nFileLength; //文件长度 8EAkM*D w  
boolean bFirst = true; //是否第一次取文件 ?Q/9aqHe;  
boolean bStop = false; //停止标志 0 hS(9y40  
File tmpFile; //文件下载的临时信息 Jtl[9qe#]  
DataOutputStream output; //输出到文件的输出流 8\rHSsP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） LYp=o8JW|  
public SiteFileFetch(SiteInfoBean bean) throws IOException "hXB_73)V  
{ ]`}R,'P  
siteInfoBean = bean; WHvxBd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e]u3[ao  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); QVQ?a&HYS  
if(tmpFile.exists ()) ZH=oQV)6  
{ 28d=-s=[  
bFirst = false; y%xn(Bn  
read_nPos(); dS"%( ?o  
} ntEf-x<  
else {9YNv<3  
{ }~$96|J  
nStartPos = new long[bean.getNSplitter()]; NTL`9b  
nEndPos = new long[bean.getNSplitter()]; ccJ!N  
} y3pr(w9A  
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} ^FN(wvqb8  
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public void run() ee{8C~  
{ O;~dao  
//获得文件长度 Pdw[#X<[`  
//分割文件 . [5{  
//实例FileSplitterFetch "jEf$]  
//启动FileSplitterFetch线程 'U3+'du^8  
//等待子线程返回 w65D;9/;  
try{ 3*$)9'  
if(bFirst) nK5FPFz8  
{ &[4lP~  
nFileLength = getFileSize(); K(B|o6[  
if(nFileLength == -1) gv,8Wo  
{ :,BKB*a\  
System.err.println("File Length is not known!"); }dO^q-t$3  
} 4]3(Vyh`  
else if(nFileLength == -2) 0s8w)%4$  
{ ZdY)&LJ  
System.err.println("File is not access!"); "Rv],O"  
} -% Z?rn2  
else 8m;tgMFO  
{ kZ3w2=x3v  
for(int i=0;i<nStartPos.length;i++) l:H}Y3_I  
{ Ff@Cs0R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); and)>$)|  
} L.) 0!1  
for(int i=0;i<nEndPos.length-1;i++) +$H`/^a.  
{ J)leRR&  
nEndPos = nStartPos[i+1]; )Y}8)/Pud  
} GV T[)jS  
nEndPos[nEndPos.length-1] = nFileLength; 7;;HP`vY  
} {@w!kl~8  
} G@Y!*ZH*f  
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//启动子线程 XUp'wP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zVU{jmS  
for(int i=0;i<nStartPos.length;i++) 1y($h<  
{ /vLdm-4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N9A#@c0O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0xQ="aXE  
nStartPos,nEndPos,i); t\
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /"%(i#<)xs  
fileSplitterFetch.start(); "`4V^1  
} bI"_hvcFp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \tx4bV#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3/q)%Z^=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QBI;aG<+b>  
nEndPos = " + nFileLength); ,aBo
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// fileSplitterFetch[nPos.length-1].start(); >=Pn\"j  
:v>Nz7SB  
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//等待子线程结束 .V Cfh+*J#  
//int count = 0; ^yo~C3r~  
//是否结束while循环 >MeM  
boolean breakWhile = false; n6Qsug$z  
_rU%DL?  

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while(!bStop) mWPA]g(  
{ l@OY8z-_  
write_nPos(); wfXm(RYM  
Utility.sleep(500);  nW*D  
breakWhile = true; E'O[E=  
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for(int i=0;i<nStartPos.length;i++) 7A mnxFC  
{ F$k^px  
if(!fileSplitterFetch.bDownOver) ?'$Y
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{ @ysc?4% q  
breakWhile = false; awic9uMH  
break; BQ7p<{G  
} H]x-s  
} /$ :w8  
if(breakWhile) )Z0bM
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break; *VPjBzcH  
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//count++; b&j}f  
//if(count>4) RU_wr<  
// siteStop(); 9_  
} +xc1cki_{  
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System.err.println("文件下载结束！"); |r%NMw #y  
} (Iz$_(  
catch(Exception e){e.printStackTrace ();} =h Lw1~  
} +-*Ww5Zti  
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//获得文件长度 3\B28m  
public long getFileSize() 4ru-qF  
{ ;qN;oSK  
int nFileLength = -1; cfP9b8JG  
try{ QU;bDNq,c  
URL url = new URL(siteInfoBean.getSSiteURL()); qG<3H!Z!ky  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Lq6R_udp  
httpConnection.setRequestProperty("User-Agent","NetFox");  UqwU3  
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int responseCode=httpConnection.getResponseCode(); W Y]  
if(responseCode>=400) ~stJO])a  
{ $,)PO Z  
processErrorCode(responseCode); IGQcQ/M  
return -2; //-2 represent access is error j*'+f~A  
} p
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String sHeader; l3O!{&~K  
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for(int i=1;;i++) S<Os\/*  
{ w$##GM=Tq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A 6IrA/b  
//Utility.log(in.readLine()); bQlvb  
sHeader=httpConnection.getHeaderFieldKey(i); g]Jt (aYK  
if(sHeader!=null)
@?vC4+'  
{ R9z:K_d,  
if(sHeader.equals("Content-Length")) p.^qB]%  
{  B8~JUGD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X;&
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break; <c77GimD?  
} QB.QG!@  
} K!,T.qA&=  
else rLpfybu  
break; NxW Dw  
} ki6Lt  
} YEPQ/Pc  
catch(IOException e){e.printStackTrace ();} ZO#f)>s2  
catch(Exception e){e.printStackTrace ();} E#!tXO&,  
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Utility.log(nFileLength); qeUT]* w  
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return nFileLength; 9,wD  
} 4^Y{ BS fF  
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//保存下载信息（文件指针位置） M '#a.z%  
private void write_nPos() TT@U_^o  
{ _1,hO?TK  
try{ +6`+Q2qi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fg)VO6Wo&  
output.writeInt(nStartPos.length); ?:42jp3  
for(int i=0;i<nStartPos.length;i++) T!7B0_  
{ xfa-  
// output.writeLong(nPos); ?Gl]O3@3  
output.writeLong(fileSplitterFetch.nStartPos); "qrde4O  
output.writeLong(fileSplitterFetch.nEndPos); S"4eS,5L|  
} @xXVJWEU:  
output.close(); 
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} awv$ }EFo  
catch(IOException e){e.printStackTrace ();} `FGYc  
catch(Exception e){e.printStackTrace ();} {sfA$ d0  
} vh#81}@N7*  
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//读取保存的下载信息（文件指针位置） ?KtF!:_C  
private void read_nPos() =(]Z%Q-V  
{ @jxP3:s  
try{ Rb!y(&>v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F
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int nCount = input.readInt(); @C|nc&E2s  
nStartPos = new long[nCount]; ObfRwZh?q  
nEndPos = new long[nCount]; w^"IR  
for(int i=0;i<nStartPos.length;i++) v YJ9G"E  
{ ;_=N YG.  
nStartPos = input.readLong(); PU,%Y_xR  
nEndPos = input.readLong(); UCt}\IJ  
} /go|r '  
input.close(); 6CCm1F{`  
} AP1&TQ,&  
catch(IOException e){e.printStackTrace ();} rQxiG[0  
catch(Exception e){e.printStackTrace ();} "<"m}rE?Q  
} e }Mf  
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private void processErrorCode(int nErrorCode) B<Q)z5KK  
{ 0NeIQr1N_  
System.err.println("Error Code : " + nErrorCode); *`q?`#1&&.  
} ", p5}}/  
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//停止文件下载 !:PiQ19 'u  
public void siteStop() -.Blj<2ah  
{ _%[po%]  
bStop = true; YF)]B|I  
for(int i=0;i<nStartPos.length;i++) mqj-/DN6*  
fileSplitterFetch.splitterStop(); ~Pj q
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} ZTibF'
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} D4b-Y[/"  
//负责部分文件的抓取 VV{>Kq+&,v  
**FileSplitterFetch.java RA!q)/+  
*/ /5<=m:  
package NetFox; 8t3m$<7  
<.mH-Y5i  
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import java.io.*; dU#-;/}o  
import java.net.*; CLTkyS)C  
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public class FileSplitterFetch extends Thread { rlaeqG  
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String sURL; //File URL D#AqZS>B  
long nStartPos; //File Snippet Start Position Q~tXT_  
long nEndPos; //File Snippet End Position m8=n`XI  
int nThreadID; //Thread's ID ?=ffv]v|  
boolean bDownOver = false; //Downing is over J#48c'  
boolean bStop = false; //Stop identical >.6|\{*sG  
FileAccessI fileAccessI = null; //File Access interface p#CjkL  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [}YUi>NGA  
{ @ 5^nrB  
this.sURL = sURL; -OSj<m<  
this.nStartPos = nStart; ^DN:.qQ  
this.nEndPos = nEnd; 8L,=E
ap  
nThreadID = id; FieDESsX>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >MGWN  
} c}+*$DeT  
*5 +GJWKN  
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public void run() <|3%}?  
{ P`ou:M{8  
while(nStartPos < nEndPos && !bStop) .%s U)$bH  
{ ~ney~Pz_  
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try{ L;* s-j6y  
URL url = new URL(sURL); NNF"si\FE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K8aqC{  
httpConnection.setRequestProperty("User-Agent","NetFox"); *68 TTBq(  
String sProperty = "bytes="+nStartPos+"-"; #]x3
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httpConnection.setRequestProperty("RANGE",sProperty); *X(:vET  
Utility.log(sProperty); X%
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InputStream input = httpConnection.getInputStream(); mwo:+^v(  
//logResponseHead(httpConnection); !(rAI  
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byte[] b = new byte[1024]; qx'0(q2Ii(  
int nRead; c7jmzo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X+C*+k,z  
{ a8f#q]TyQ  
nStartPos += fileAccessI.write(b,0,nRead); |82q|@e  
//if(nThreadID == 1) F?|Efpzow?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HJ]xZ83pC  
} W|7|XO  
? Bpnnwx  
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Utility.log("Thread " + nThreadID + " is over!"); @^<odmM  
bDownOver = true; 1>OlBp  
//nPos = fileAccessI.write (b,0,nRead); R(d<PlZ  
} J(l\VvK  
catch(Exception e){e.printStackTrace ();} st;i
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} wX0D^)NtF  
} N<9 c/V  
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//打印回应的头信息 2ZY$/  
public void logResponseHead(HttpURLConnection con) 68XJ`/d  
{ 0&UG=q  
for(int i=1;;i++) }6@E3z]AMO  
{ 8f9wUPr  
String header=con.getHeaderFieldKey(i); 2%sZaM  
if(header!=null) `qc"JB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NX&dJ 6a  
Utility.log(header+" : "+con.getHeaderField(header)); mol,
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else rx2)uUbR  
break; TQ]gvi|m  
} Z)s !p  
} gz~oQ l)zJ  
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public void splitterStop() 9wYm(7M6  
{ ,`}yJ*7  
bStop = true; 7|5kak>=  
} A0<g8pv  
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} ;k!.ey$S  
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/* ,`bW(V  
**FileAccess.java |M;Nq@bRv  
*//文件访问(定位，写) ?>
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package NetFox; G'\[dwD,u  
import java.io.*; ^3dc#5]Xf  
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public class FileAccessI implements Serializable{ :qdyCsn2  
6\.g,>   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Gd 4S7JE  
RandomAccessFile oSavedFile; p& _Z}Wv  
long nPos; n+8YTjd  
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public FileAccessI() throws IOException uVqc:Q"  
{ jlBsm'M<m  
this("",0); M7/5e3  
} NCKR<!(  
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v@{y}  
public FileAccessI(String sName,long nPos) throws IOException Xex7Lr&  
{ X%YZQc9  
oSavedFile = new RandomAccessFile(sName,"rw"); `,V&@}&"n  
this.nPos = nPos; }ppApJT  
oSavedFile.seek(nPos); ! v![K
  
} b$'%)\('g  
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public synchronized int write(byte[] b,int nStart,int nLen) B
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{ -9om,U`t  
int n = -1; Tv|'6P  
try{ }ekNZNcuM  
oSavedFile.write(b,nStart,nLen); k M/:
n  
n = nLen; 0kUhz\"R:q  
} w~+*Vd~U  
catch(IOException e) D+!T5)>(  
{ K}cZK  
e.printStackTrace (); &>c=/]Lop  
} 7**zb"#y  
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return n; s]m]b#1!r  
} %72# tY  
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} #X)DFAtb  
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,O:4[M!$w  
/* ()|e xWW  
**SiteInfoBean.java YHN6/k7H  
*/ f4S}Nga(  
package NetFox; oT}$N_gFT  
d[h=<?E5  
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public class SiteInfoBean { >(2;(TbQm0  
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private String sSiteURL; //Site's URL 2po8n_  
private String sFilePath; //Saved File's Path EZWWvL  
private String sFileName; //Saved File's Name bzG vnaTt  
private int nSplitter; //Count of Splited Downloading File J)g +I  
:30daKo  
|~76dxU  
public SiteInfoBean() I_B%F#X)  
{//nSplitter的缺省值为5 IYe[IHny1  
//default value of nSplitter is 5 &DQ_qO
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this("","","",5); [p4([ef '  
} rv{Wti[  
s {*rBX8N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t,Tq3zB  
{ =>S[Dh  
sSiteURL= sURL; v1$}[&/  
sFilePath = sPath;  \&d1bq  
sFileName = sName; lGet)/w;c  
this.nSplitter = nSpiltter; ]#N8e?b,  
;-i)}<  
vo#$xwm1  
} \ $TM=Ykj  
T pCXe\W  
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public String getSSiteURL() <DMm [V{  
{ l )r^|9{  
return sSiteURL; 0]ai*\,W7~  
} sfVzVS[  
`_&vvJPn@!  
K z^.v`  
public void setSSiteURL(String value) "'+/ax[{  
{ A/zAB3  
sSiteURL = value; M\ wCZG  
} rhF2U  
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public String getSFilePath() N/C$8D34  
{ #x;d+Q@  
return sFilePath; An]Vx<PD  
} =m|<~t  
2n"-~'3\  
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public void setSFilePath(String value) ,H
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{ pw))9~XU  
sFilePath = value; u$qasII  
} VaonG]Ues  
;Zf7|i`R3  
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public String getSFileName() 9AWP`~l`  
{ ']!wc8m1"  
return sFileName; [$6YPM>Ee  
} ;Gp9 ?0  
2*W|s7cc  
uKY1AC__  
public void setSFileName(String value) L{ej<0yr  
{ IM,d6lN6s  
sFileName = value; >z3l@  
} nr>Yj?la  
0#5
&*  
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public int getNSplitter() -f'&JwE0=  
{ [:izej(\  
return nSplitter; v)vogtAQa  
} K6F05h 5S  
t[H
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public void setNSplitter(int nCount) *>GRU8_}  
{ %U[H`E  
nSplitter = nCount; B<|Vm.D  
} 5IgO4<B  
} 6!6R3Za$  
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{iQ4jJ`n  
/* \+ Ese-la  
**Utility.java |]HA@7B  
*/ +Lr`-</VF  
package NetFox; Eg4&D4TGp  
Q*f0YjH!  
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public class Utility { xgsEe3|  
/+<G@+(  
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public Utility()
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{ ;iN[du  
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'^Q$:P{G?  
} *\0h^^|
@  
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//线程睡眠 A0ZU
#"'/  
public static void sleep(int nSecond) ASSe;+yp  
{ X=jD^"-  
try{ fG@]G9Z  
Thread.sleep(nSecond); ]P_yN:~  
} zq$0 ?vGd  
catch(Exception e) bdBLfWe  
{ ;e2D}  
e.printStackTrace (); .8|"
@  
} qP9`p4c8i  
} xjYH[PgfX  
O^~nf%  
//日志 a0k/R<4  
public static void log(String sMsg) q:wz!~(>  
{ (AG((eV  
System.err.println(sMsg); &jr
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} 7a4Z~r27/  
8qUNh#  
t#!AfTY$w  
public static void log(int sMsg) .|:R#VW  
{ 4`sW_ ks  
System.err.println(sMsg); `Gg,oCQg  
} 5p7i9"tgn  
} KO))2GET  
e[QEOx/-h2  
HSACaTVK  
/* /W{^hVkvC  
**TestMethod.java w,1*dn  
*/ XCGK&OGI  
package NetFox; 0Fs2* FS  
"JgwL_2  
_Q*,~ z~  
public class TestMethod { MdnapxuS  
FW4#/H  
rj29$d?Y9  
public TestMethod() rLp0)Go  
{ ///xx/weblogic60b2_win.exe <. V*]g/;  
try{ ~T=a]V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \O*W/9 +  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :?gp}.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %y+v0.aWH+  
fileFetch.start(); Q^'xVS_.  
} Om8Sgy?  
catch(Exception e){e.printStackTrace ();} 3[R[`l]v?  
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} Jb|dpu/e  
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public static void main(String[] args) EiPOY'  
{ C jz(-018  
new TestMethod(); nKch:g  
} ?0d#O_la3  
} }gQnr;lv  
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