http断点续传简单实现（java)

/* kyp U&F  
**SiteFileFetch.java i!s~kk  
*/ 41P4?"O  
package NetFox; p_D on3  
import java.io.*; !&
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import java.net.*; ~)WfJ  
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public class SiteFileFetch extends Thread { >#Grf)@"6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <=B1"'\  
long[] nStartPos; //开始位置 ?Cc
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long[] nEndPos; //结束位置 Qi(e`(,'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f\U?:83  
long nFileLength; //文件长度 O>)n*OsS  
boolean bFirst = true; //是否第一次取文件 X}n&`y{/  
boolean bStop = false; //停止标志 yVu^ >  
File tmpFile; //文件下载的临时信息 +?4*,8Tmmz  
DataOutputStream output; //输出到文件的输出流 6E)uu; 8  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4\ uZKv@,  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;]l{D}  
{ QZ:]8MHl]  
siteInfoBean = bean; Vz=j)[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 's56L,^:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b#/V;  
if(tmpFile.exists ()) %l9WZ*yZ`2  
{ KxgR5#:i"  
bFirst = false; pqGf@2
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read_nPos(); SopNtcu!  
} Y]`lEq%  
else a!hI${Xn  
{ Gdc~Lh  
nStartPos = new long[bean.getNSplitter()]; E980yX
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nEndPos = new long[bean.getNSplitter()]; +Y.uZJ6+  
} s%S_K  
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} 4cVs(`g^  
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public void run() ;/hH=IT  
{ ba:mO$  
//获得文件长度 l/y Kc8^<  
//分割文件 Xdp`Z'g  
//实例FileSplitterFetch YWn6wzu%Vc  
//启动FileSplitterFetch线程 #:Sy`G6!?  
//等待子线程返回 C&d"#I  
try{ X-;Qorb^  
if(bFirst) FRJ:ym=E  
{ AT'_0>x8  
nFileLength = getFileSize(); v|,[5IY  
if(nFileLength == -1) k1LtqV  
{ _sf0{/< )  
System.err.println("File Length is not known!"); A aF5`  
} w7*b}D@65\  
else if(nFileLength == -2) hAxuZb7 ?  
{ wYcz\uV  
System.err.println("File is not access!"); \aJ-q?=   
} <>
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else CrwcYzrRWl  
{ Z+h70,|  
for(int i=0;i<nStartPos.length;i++) `Hp.%G(  
{ ZjI/zqBm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a*n%SUP  
} luxKgcU  
for(int i=0;i<nEndPos.length-1;i++) =ZJ?xA8  
{ E 4$h%5  
nEndPos = nStartPos[i+1]; @)juP- o%  
} @,>=X:7  
nEndPos[nEndPos.length-1] = nFileLength; Xw}Y!;<IEu  
} |uBot#K|  
} YV_I-l0  
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//启动子线程 @vYN7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4Z T  
for(int i=0;i<nStartPos.length;i++) t[yD8h  
{ !=Kay^J~.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &+w!'LSaD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '/qe#S  
nStartPos,nEndPos,i); K&P{2Hndr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =iN_Ug+  
fileSplitterFetch.start(); g2b4 ia!L  
} JjO/u>A3;7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^{sI'l~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BaHgc 4zI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %?G.lej,x  
nEndPos = " + nFileLength); t T/*ZzMq#  
// fileSplitterFetch[nPos.length-1].start(); 9(
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rJ~(Xu>,s  
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//等待子线程结束 ="TOa"Zk  
//int count = 0; (pxz#B4  
//是否结束while循环 Bma|!p{  
boolean breakWhile = false; {Ll8@'5  
D '_#?%3^  
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while(!bStop) ]8cX#N,M  
{ 6!=9V0G~  
write_nPos(); /n}V7  
Utility.sleep(500); J-{E`ibGN  
breakWhile = true; Z5^UF2`Q  
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for(int i=0;i<nStartPos.length;i++) LZbHK.G=  
{ K<9MK>T  
if(!fileSplitterFetch.bDownOver) aj-uk(r  
{ iQj{J1V  
breakWhile = false; x,*t/nzR  
break; :[?o7%"  
} G8c}re   
} (c7{dYV  
if(breakWhile) F(n))`(  
break; aRKG)0=  
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!7kOw65+0  
//count++; s-DL=M
D  
//if(count>4) *iN]#)3>  
// siteStop(); H;te)km}  
} ?S7:KnU>K  
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System.err.println("文件下载结束！"); HpC4$JMm  
} qUg
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catch(Exception e){e.printStackTrace ();} !|QeYGnq6  
} %),O9*[9  
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9!C?2*>A P  
//获得文件长度 ~ +$><qj  
public long getFileSize() PiQs><FK8  
{ ';V+~pi  
int nFileLength = -1; P &._-[  
try{ LA Vgf>  
URL url = new URL(siteInfoBean.getSSiteURL()); (3*Hl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KO"iauW  
httpConnection.setRequestProperty("User-Agent","NetFox"); $B/cj^3  
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#8|NZ6x,  
int responseCode=httpConnection.getResponseCode(); $ wB  
if(responseCode>=400) A1;t60z+q>  
{ Sw)ftC~d  
processErrorCode(responseCode); U#4W"1~iX  
return -2; //-2 represent access is error [: j_Y3-9  
} S5!2%-;<k  
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String sHeader; "j>0A Hem  
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for(int i=1;;i++) ?[">%^  
{ u] b6>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3!x)LUWfWY  
//Utility.log(in.readLine()); 7 #N @B  
sHeader=httpConnection.getHeaderFieldKey(i); jd*H$BU^  
if(sHeader!=null) p}uw-$O  
{ G_]mNh  
if(sHeader.equals("Content-Length")) j>23QPG`6U  
{ H[Cn@XE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Nh%8;  
break; `^[ra%
a  
} jL$X3QS:  
} f*Bc`+G  
else 'l;|t"R12  
break; 2F(j=uV+  
} E{J
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} z_)$g=9$  
catch(IOException e){e.printStackTrace ();} =t2epIr5  
catch(Exception e){e.printStackTrace ();} _De;SB%V  
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Utility.log(nFileLength); xuF_^  
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return nFileLength;  VM`."un]  
} [cq>QMW  
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//保存下载信息（文件指针位置） 4M}/PoJ  
private void write_nPos() _
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{ QB3AL;7  
try{ t<tBOesQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M=%p$\x
  
output.writeInt(nStartPos.length); sQw-#f7t  
for(int i=0;i<nStartPos.length;i++) n)yqb  
{ jBM>Pe^`3  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); [Pay<]c6g  
output.writeLong(fileSplitterFetch.nEndPos); cQjJ9o7  
} %?seX+ne  
output.close(); &IPT$=u  
} iBQftq7  
catch(IOException e){e.printStackTrace ();} 4(NI-|q0  
catch(Exception e){e.printStackTrace ();} 2B#\683  
} 9Bn dbSi  
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//读取保存的下载信息（文件指针位置） |zf||ju  
private void read_nPos() Y+E@afsKs  
{ Z'E@sc 9  
try{ Z(s} #-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a[/p(O  
int nCount = input.readInt(); ?~$y3<[  
nStartPos = new long[nCount]; G} p~VLf  
nEndPos = new long[nCount]; u^uW<.#z  
for(int i=0;i<nStartPos.length;i++) *m7e>]-  
{ 5g=" #  
nStartPos = input.readLong(); aaBBI S  
nEndPos = input.readLong(); uo0(W3Q *  
} 6-oQs?  
input.close(); 975KRnj  
} !vU[V,~  
catch(IOException e){e.printStackTrace ();} >[#4Pb7_Y  
catch(Exception e){e.printStackTrace ();} Cs$g]&a  
} .p&M@h w  
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private void processErrorCode(int nErrorCode) zw0p}  
{ \(u P{,ML  
System.err.println("Error Code : " + nErrorCode); {*: C$"L  
} ALG +  
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i}Y:o}  
//停止文件下载 u+]zi"k^s  
public void siteStop() iaMZ37  
{ I?1^\s#L  
bStop = true; 5EU3BVu&u  
for(int i=0;i<nStartPos.length;i++) wBr0s*1I  
fileSplitterFetch.splitterStop(); p4/
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} iM\W"OUl[  
} [[Z*n/tr  
//负责部分文件的抓取 uG
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**FileSplitterFetch.java  M;V2O;  
*/ gG#M-2P  
package NetFox; i# QI}r  
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import java.io.*; M]oaWQu  
import java.net.*; m~2PpO  
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public class FileSplitterFetch extends Thread { XXO  
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String sURL; //File URL C}7Sh6  
long nStartPos; //File Snippet Start Position O Qd,.m  
long nEndPos; //File Snippet End Position 59GS:  
int nThreadID; //Thread's ID T$SGf.-  
boolean bDownOver = false; //Downing is over aCQAh[T  
boolean bStop = false; //Stop identical SDZ/r
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FileAccessI fileAccessI = null; //File Access interface oB+drDp8U  
[V =O$X_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zhf+u r  
{ {"-uaH>,  
this.sURL = sURL; c1c8):o+V  
this.nStartPos = nStart; Oo$i,|$$  
this.nEndPos = nEnd; ih~ R?W  
nThreadID = id; :W^ k3/t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y'0H2B8  
} /alJN`g  
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public void run() M/T ll]\|  
{ xO{yr[x"L  
while(nStartPos < nEndPos && !bStop) YB*I'm3q  
{ mSr(PIH{\  
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(} ?")$.  
try{ qi!+Ceo}  
URL url = new URL(sURL); ,Tjc\;~%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yJNQO'wcv  
httpConnection.setRequestProperty("User-Agent","NetFox"); =)!sWY:  
String sProperty = "bytes="+nStartPos+"-"; z&Cz!HrS  
httpConnection.setRequestProperty("RANGE",sProperty); 0w)Gb}o$  
Utility.log(sProperty); ?NWc3 .  
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*> LA30R*v  
InputStream input = httpConnection.getInputStream(); q
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//logResponseHead(httpConnection); j`7q
7}  
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byte[] b = new byte[1024]; grrM[Y7#~b  
int nRead; *3 8 u ~n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :Y>FuE  
{ stQRl_('  
nStartPos += fileAccessI.write(b,0,nRead); mBN+c9n/  
//if(nThreadID == 1) :8=7)cW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 );8z!+  
} #83`T&Xw*  
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$Y`oqw?g+^  
Utility.log("Thread " + nThreadID + " is over!"); (P'{A>aHl0  
bDownOver = true; Vq$8!#~w  
//nPos = fileAccessI.write (b,0,nRead); >zA*W<g  
} [] cF*en  
catch(Exception e){e.printStackTrace ();} '-X[T}  
} s k_TKN`+  
} q]Vxf!0*>
 
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//打印回应的头信息 z_f^L %J0  
public void logResponseHead(HttpURLConnection con) ^m Ua5w  
{ L0.F}~S  
for(int i=1;;i++) vB<9M-sa0  
{ -kzp>=  
String header=con.getHeaderFieldKey(i); V9Pw\K!w#\  
if(header!=null) tJ$gH;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `NySTd)\  
Utility.log(header+" : "+con.getHeaderField(header)); fDjJdRS"  
else L.2!Q3&  
break; LIE5of  
} G,!{Q''w  
} 2Q=I`H_  
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public void splitterStop()
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{ uA4xxY  
bStop = true; E5qt~:C|  
} NK\0X5##.  
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} ka/>jV"  
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/* @>*r2=#14  
**FileAccess.java 5[LDG/{Tys  
*//文件访问(定位，写) ;Wg
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package NetFox; :.=#U  
import java.io.*; '""s%C+  
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public class FileAccessI implements Serializable{ .On3ZN  
NvvD~Bb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yMEI^,0"  
RandomAccessFile oSavedFile; %$_Y"82  
long nPos; vRb7=fXf  
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public FileAccessI() throws IOException fu iTy72  
{ }{}?mQ  
this("",0); P~84#5R1  
} _\<TjGtG  
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public FileAccessI(String sName,long nPos) throws IOException /[5\T2GI  
{ a4XK.[O  
oSavedFile = new RandomAccessFile(sName,"rw"); X4L@|"ZI  
this.nPos = nPos; Wcbm,O4u  
oSavedFile.seek(nPos); nub!*)q  
} 0v#p4@Z  
{113B)  
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public synchronized int write(byte[] b,int nStart,int nLen) cSjX/%*!m  
{ ^B8[B&K  
int n = -1; cT@H49#uB  
try{ LVy`U07CV  
oSavedFile.write(b,nStart,nLen); e~SRGyIww  
n = nLen; hY/qMK5  
} *TrpW?]Y&  
catch(IOException e) <E:_9#Z0sc  
{ - _~\d+>w  
e.printStackTrace (); N/[!$B0H@  
} G^Y^)pc]   
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return n; K+d{R=s^  
} 9I}Uh#]k<  
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} 3[@:I^q  
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#=72/[  
/* nkz<t   
**SiteInfoBean.java W)^%/lAh  
*/ l3y}nh+ 8  
package NetFox; B`w8d[cL7  
$h}w:AV:  
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public class SiteInfoBean { E&Zt<pRf;2  
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private String sSiteURL; //Site's URL o?
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private String sFilePath; //Saved File's Path k8i0`VY5Y  
private String sFileName; //Saved File's Name HG)$W  
private int nSplitter; //Count of Splited Downloading File f%JM a]yV  
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public SiteInfoBean() GnCs_[*&r  
{//nSplitter的缺省值为5 +U>Y.YP  
//default value of nSplitter is 5 }2^qM^,0  
this("","","",5); 99%R
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} Q(R-8"  
/>uE)R$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 79D;0  
{ roBbo  
sSiteURL= sURL; Zqv  
sFilePath = sPath; 3JD"* <zs  
sFileName = sName; Q'Uv5p"X  
this.nSplitter = nSpiltter; uZ+"-Ig  
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NCYOY  
} 4F<was/  
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ks,d4b=->  
public String getSSiteURL() x7i,jMR  
{ KM[&WT  
return sSiteURL; |x=(}g  
} @RCZ![XYWg  
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vg1E@rH
|}  
public void setSSiteURL(String value) .Q{VY]B^  
{ FTzc,6  
sSiteURL = value; LG{50sP`  
} !Q}Bz*Y  
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public String getSFilePath() &o&}5Aba9  
{ kX*.BZI}C  
return sFilePath; HIvSh6|0p  
} feM(  
d"a\`#  
y>cT{)E$  
public void setSFilePath(String value) dIA1\;@  
{ ,,g: x  
sFilePath = value; J:IAs:e`  
} g>a% gVly  
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public String getSFileName() C?<[oQb#  
{ 2ppJ;P{k  
return sFileName; 0}e&ONDQ  
} gEmsPk,  
<
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R$">
 
public void setSFileName(String value) }_Y\6fcd  
{ Y+EwBg)co  
sFileName = value; (m')dSZ  
} Bi0&F1ZC!  
@-ir
 
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public int getNSplitter() 3'7X[{uBr  
{ `0=j,54cx  
return nSplitter; :Yi 4Ia  
} >/.Ae8I)  
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public void setNSplitter(int nCount) @Dd(  
{ 2W/*1K}  
nSplitter = nCount; V|4k=_-  
} "&\]1A}Z-x  
} }dEf |6_  
/f>I;z1  
<}%gZ:Z6g  
/* p(yHB([8  
**Utility.java B^j(Fq  
*/ //#]CsFiP  
package NetFox; iUS?xKN$~-  
Ft@ZK!'@  
'~xjaa;.  
public class Utility { `t7GYmw^#  
:|=Xh"l"  
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public Utility() 9hhYyqGsO  
{ &Z+.FTo  
sb%l N  
@nM+*0 $d  
} *#B"%;Ln  
2K2*UC`f  
//线程睡眠 ro^T L  
public static void sleep(int nSecond) Fz]!2rt  
{ :(4];Va  
try{ l, -q:8  
Thread.sleep(nSecond); p
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} Rm@F9D[,  
catch(Exception e)  \>e>J\t:  
{ p49T3V  
e.printStackTrace (); J 77*Ue^  
} rmdG"s  
} ?WrL<?r)}U  
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//日志 nY?X@avo>  
public static void log(String sMsg) 2/l4,x  
{ TA+/35^?  
System.err.println(sMsg); Cx8  H  
}
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L$}'6y/@  
9`DY6qfly  
public static void log(int sMsg) |d_ rK2  
{ |bjLmGb  
System.err.println(sMsg); \LDcIK=  
} 6X$iTJ[\x  
} E>qehs,g  
=L}$#Y8?  
q<A,S8'm  
/* *q(H
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**TestMethod.java ,CnUQx0  
*/ Xd9<`gu  
package NetFox; %l)~C%T  
U,nQnD"!t&  
v5`Odbc=w  
public class TestMethod { aB4L$M8x  
LP}YHW/  
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public TestMethod() n`7n5M*  
{ ///xx/weblogic60b2_win.exe SP5t=#M6  
try{ ZQrgYeQl"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xqaw00,s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lV2MRxI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s&qr2'F+z  
fileFetch.start(); R)qK{wq(1E  
} nB86oQ/S  
catch(Exception e){e.printStackTrace ();} +PkN~m`  
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} &8 4Izs/[  
]lzOz<0q  
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public static void main(String[] args) \{`*`WQF  
{ 2E}^'o  
new TestMethod(); MFLw^10(T  
} bLyG3~P;0  
} _fANl}Mf:  
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