http断点续传简单实现（java)

/* JE5  
**SiteFileFetch.java 7T``-:`[  
*/ \e=_ 2^v!_  
package NetFox; pD"vRbYF  
import java.io.*; f8 /'%$N  
import java.net.*; $aCd/&  
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public class SiteFileFetch extends Thread { -F&U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }TRAw#h  
long[] nStartPos; //开始位置 8eIUsI.o  
long[] nEndPos; //结束位置 +'@+x'/{^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h!@|RW&}qX  
long nFileLength; //文件长度 <^.=>Q0S\  
boolean bFirst = true; //是否第一次取文件 !2\ r LN  
boolean bStop = false; //停止标志 gyHHoZc3  
File tmpFile; //文件下载的临时信息 :nHKl  
DataOutputStream output; //输出到文件的输出流 /StTb,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） p=GWq(S6  
public SiteFileFetch(SiteInfoBean bean) throws IOException MiT}L  
{ v dbO(  
siteInfoBean = bean; .9*wY0:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -hcS]~F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]G.%Ty  
if(tmpFile.exists ()) p?[Tm*r  
{ (GnuWc\p  
bFirst = false; `J<*9dq%  
read_nPos(); +[@z(N-h  
} j| Wv7  
else ?PA$Ur21lw  
{ K`&oC8p  
nStartPos = new long[bean.getNSplitter()]; N/YWby=H  
nEndPos = new long[bean.getNSplitter()]; 75nNh~?)\  
} v`J*ixZ7t  
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} vE6mOM!_L  
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public void run() v$~QCtc  
{ w&$d* E  
//获得文件长度 #&<)! YY5  
//分割文件 # ?1Sm/5k`  
//实例FileSplitterFetch [P zv4+  
//启动FileSplitterFetch线程 rD?L  
//等待子线程返回 2n><RZ/9  
try{ ~"pKe~h   
if(bFirst) R2etB*k6[  
{ c0c|z Ym  
nFileLength = getFileSize(); 7g=2Z[o  
if(nFileLength == -1) lPH%Do>K  
{ VUTacA Y>L  
System.err.println("File Length is not known!"); O1%pxX'`S  
} kp?w2+rz  
else if(nFileLength == -2) AL/?,%F  
{ 7*j (*  
System.err.println("File is not access!"); M)*\a/6?{  
} ~DO4,  
else 4%WzIzRb  
{ s?8<50s  
for(int i=0;i<nStartPos.length;i++) G6V
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{ 4?N8R$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jR=s#Xz  
} T|&[7%F3"  
for(int i=0;i<nEndPos.length-1;i++) jF`BjxrG  
{ ob+euCuJ  
nEndPos = nStartPos[i+1]; RMO,ZVq  
} 6
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nEndPos[nEndPos.length-1] = nFileLength; xI,2LGO  
} yx V:!gl  
} 80A.<=(=.  
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//启动子线程 W\1i,ew>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (E,T#uc{  
for(int i=0;i<nStartPos.length;i++) zf3v5Hk  
{ Y
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J0zn-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +C7 ~b~ %  
nStartPos,nEndPos,i); zMIT}$L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); **69rN  
fileSplitterFetch.start(); {M,,npl  
} ^Rm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), No2b"G@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !lo/xQ<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }b1cLchl  
nEndPos = " + nFileLength); CJ}5T]WZ  
// fileSplitterFetch[nPos.length-1].start(); :JlP[I  
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;lYHQQd!,  
//等待子线程结束 P`r55@af4  
//int count = 0; d[rv1s>i  
//是否结束while循环 9@Cv5L?p\  
boolean breakWhile = false; bINvqv0v  
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while(!bStop) Wg`R_>qQSm  
{ oyo(1>  
write_nPos(); [qsEUc+Z.'  
Utility.sleep(500); SkU9ON  
breakWhile = true; 0M\D[mg  
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for(int i=0;i<nStartPos.length;i++) 8Lw B B  
{ mf'V)  
if(!fileSplitterFetch.bDownOver) /VG2.:  
{ A'P(a`  
breakWhile = false; \h8
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break; tHLrhH<w  
} A!^q J#  
} Z|}G6]h  
if(breakWhile) HSq}7S&U  
break; "`N-*;*W  
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//count++; uslQ*7S[^  
//if(count>4) 4@xE8`+bG  
// siteStop(); E!S 78z:  
} |JCU<_<  
=-p$jXVW%  
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System.err.println("文件下载结束！"); HV<Lf 6gE  
} 4j)tfhwd8  
catch(Exception e){e.printStackTrace ();} l&?ii68/  
} Yw0[[N<SW  
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//获得文件长度 j
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public long getFileSize() Y".RPiTL  
{ r7qh>JrO  
int nFileLength = -1; kBN+4Dr/$  
try{ TsTPj8GAl[  
URL url = new URL(siteInfoBean.getSSiteURL()); g:EVhuK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /&4U6a  
httpConnection.setRequestProperty("User-Agent","NetFox"); ++E3]X|  
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int responseCode=httpConnection.getResponseCode(); W6Y@U$P#G  
if(responseCode>=400) ]kboG%Dl?9  
{ j1(D]Z=\  
processErrorCode(responseCode); "Iix )Ue  
return -2; //-2 represent access is error 71l%MH  
} ~zw]5|  
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String sHeader; z<5m fAm  
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for(int i=1;;i++) Qa.uMq  
{ jq!tT%o*B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4 uQT5  
//Utility.log(in.readLine()); YX#-nyK  
sHeader=httpConnection.getHeaderFieldKey(i); @$z<i `4  
if(sHeader!=null) e>AE8T  
{ {`w;39$+  
if(sHeader.equals("Content-Length")) R=KQ  
{ vI@%F
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |n] d34E  
break; FJd]D[h  
} qcT'nZ:  
} y\x+  
else 3
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break; [n/hkXa$\  
} bAx?&$  
} iya"ky~H  
catch(IOException e){e.printStackTrace ();} s8h-,@p  
catch(Exception e){e.printStackTrace ();} )K2HK&t:  
& j+oJasI  
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Utility.log(nFileLength); ?y!E-&  
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return nFileLength; ^k\e8F/  
} nakYn  
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//保存下载信息（文件指针位置） LWt&3  
private void write_nPos() c?@T1h4  
{ OiP!vn}k  
try{ n-@j5w+k4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u#@Q:tnN_  
output.writeInt(nStartPos.length); q?ix$nKOv  
for(int i=0;i<nStartPos.length;i++) "V}[':fen  
{ ny54XjtG,  
// output.writeLong(nPos); H8On<C=  
output.writeLong(fileSplitterFetch.nStartPos); Z@$8I{}G  
output.writeLong(fileSplitterFetch.nEndPos); l(#)WWr+  
} `F>O;>i''  
output.close(); fX|Y;S-@+  
} _hk.2FV:3m  
catch(IOException e){e.printStackTrace ();} ~appY Av  
catch(Exception e){e.printStackTrace ();} mtj
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} f^.AD-  
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//读取保存的下载信息（文件指针位置） QMpoa5ZQG  
private void read_nPos() 3F
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{ )[|3ZP`  
try{ s4uhsJL V$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s91JBP|B7  
int nCount = input.readInt(); UMcgdJB  
nStartPos = new long[nCount]; <(-hx+^  
nEndPos = new long[nCount]; /n8B,-Z5s5  
for(int i=0;i<nStartPos.length;i++) L:'J Bhg  
{ 5hy""i  
nStartPos = input.readLong(); J`^I./  
nEndPos = input.readLong(); ,xxR\}  
} 9\DQ>V TQ  
input.close(); eh5gjSqx  
} 0p\@!Z H  
catch(IOException e){e.printStackTrace ();} I2nhqJy^  
catch(Exception e){e.printStackTrace ();} W!&vul5  
} Jtk|w[4L  
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private void processErrorCode(int nErrorCode) Mwr
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{ HF.^
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System.err.println("Error Code : " + nErrorCode); 82DmG@"s2  
}  ({=gw9f  
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//停止文件下载 KFwzy U"  
public void siteStop() yu/`h5&*  
{ |1>*;\o-  
bStop = true; JC3m.)/  
for(int i=0;i<nStartPos.length;i++) >L 0_dvr  
fileSplitterFetch.splitterStop(); 1OF& *  
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} ^:Gie  
} \<)9?M
:  
//负责部分文件的抓取 4zo5}L`Y  
**FileSplitterFetch.java 6Avw-}.7>  
*/ E!P yL>){  
package NetFox; 7[}xP#Z  
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import java.io.*; " _ka<R..  
import java.net.*;
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public class FileSplitterFetch extends Thread { L-k@-)98  
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String sURL; //File URL cu/5$m?xx  
long nStartPos; //File Snippet Start Position 9*1,!%]  
long nEndPos; //File Snippet End Position /Dj=iBO  
int nThreadID; //Thread's ID 8!Ww J Oe  
boolean bDownOver = false; //Downing is over 7F{3*`/6  
boolean bStop = false; //Stop identical '5|h)Q5  
FileAccessI fileAccessI = null; //File Access interface `p;I}  
9Q+'n$s0^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9AJ7h9L  
{ b8LLr;oQw  
this.sURL = sURL; y`XU~B)J1  
this.nStartPos = nStart; O
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this.nEndPos = nEnd; :HwA 5Z#  
nThreadID = id; )(384@'"u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A'&K/)Z  
} 07^iP>?  
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public void run() yLQ*"sw\  
{ 2P@sn!*{1  
while(nStartPos < nEndPos && !bStop) uvG]1m#  
{ Kiu_JzD  
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try{ \hEN4V[  
URL url = new URL(sURL); o_^?n[4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J\M>33zu  
httpConnection.setRequestProperty("User-Agent","NetFox"); A*/HjTX  
String sProperty = "bytes="+nStartPos+"-";  O2%?  
httpConnection.setRequestProperty("RANGE",sProperty); De(Hw& IV  
Utility.log(sProperty); ~,B5Hc 2  
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InputStream input = httpConnection.getInputStream(); D,k"PaLP  
//logResponseHead(httpConnection); Y/ .Z.FD`  
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byte[] b = new byte[1024]; T, )__h  
int nRead; lUvpszH=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?I~()]k5  
{ >^*+iEe  
nStartPos += fileAccessI.write(b,0,nRead); M 4?ig}kh  
//if(nThreadID == 1) W)f/0QX}W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @3C>BLI8+  
} =t H:,SH  
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Utility.log("Thread " + nThreadID + " is over!"); Tw;3_Lj  
bDownOver = true; ([m mPyp>L  
//nPos = fileAccessI.write (b,0,nRead); !~rY1T~  
} NP/Gn6fr  
catch(Exception e){e.printStackTrace ();} P<a)25be/  
} jT]0WS-b  
} :6Lx@  
&N\jG373  
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//打印回应的头信息 [8*jw'W|[  
public void logResponseHead(HttpURLConnection con) ^!<BQP7  
{ L"4mL,  
for(int i=1;;i++) h1B16)  
{ r[b(I@T+  
String header=con.getHeaderFieldKey(i); SfaQvs
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if(header!=null) $4 S@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); to DG7XN}  
Utility.log(header+" : "+con.getHeaderField(header)); dE4L=sTEsy  
else sE Q=dcK  
break; 3 +G$-ru  
} bj>v|#r^  
} rzm:Yx  
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public void splitterStop() 0dGAP  
{ e'~J,(fB  
bStop = true; P'Ux%Q+B>  
} UJCYs`y  
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} /2=#t-p+  
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/* { + Zd*)M[  
**FileAccess.java Pa V@aM~3  
*//文件访问(定位，写) `\#B18eU  
package NetFox; 0"\H^
  
import java.io.*; @M_oH:GV  
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public class FileAccessI implements Serializable{ hog=
ut  
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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 GS a[ oh  
RandomAccessFile oSavedFile; ;h*K}U  
long nPos; `Nb[G)Xh  
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public FileAccessI() throws IOException B"TAjB& *  
{ P(,p'I;j  
this("",0); ZaV8qAsP  
} ['B?i1 .  
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public FileAccessI(String sName,long nPos) throws IOException <b`E_  
{ rA5=dJ"I  
oSavedFile = new RandomAccessFile(sName,"rw"); x7jC)M<k0  
this.nPos = nPos; X.f>'0i  
oSavedFile.seek(nPos); O&4SCVZp  
} AP7Yuv`  
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public synchronized int write(byte[] b,int nStart,int nLen) AGQ#$fh>7=  
{ Sjyoc<Uo  
int n = -1; ER5gmmVP@p  
try{ &eCa0s?mI  
oSavedFile.write(b,nStart,nLen); )4<__|52"1  
n = nLen; W&&;:Fr  
} mpuq 9)6  
catch(IOException e) YaKeq5%y  
{ TgmnG/Z  
e.printStackTrace (); ;CmS ~K:  
} Y2ZT.l  
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return n; zQ@I}K t  
} m'6&9Jak  
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} A: 5x|  
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/* mpI5J'>]  
**SiteInfoBean.java q)S^P>  
*/ {mZC$U'  
package NetFox; '_w=k4  
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public class SiteInfoBean { xLNtIzx  
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private String sSiteURL; //Site's URL ypKUkH/  
private String sFilePath; //Saved File's Path hbzC#@q  
private String sFileName; //Saved File's Name wKZ$iGMbz  
private int nSplitter; //Count of Splited Downloading File `\T]ej}zvI  
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public SiteInfoBean() -:2$ %  
{//nSplitter的缺省值为5 dJ2Hr;Lc  
//default value of nSplitter is 5 R7$:@<:g  
this("","","",5); 9[b<5Llt  
} wRcAX%n&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^)(bM$(`  
{ ~P8tUhff
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sSiteURL= sURL; T>}5:,N~  
sFilePath = sPath; 66/3|83Z  
sFileName = sName; 5][Ztx  
this.nSplitter = nSpiltter; @kpv{`Y  
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} iOR_[y,  
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public String getSSiteURL()
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{ Sp@^XmX(S  
return sSiteURL; <tF9V Jq  
}
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public void setSSiteURL(String value) R:e<W/P"  
{ hd>aZ"nm1  
sSiteURL = value; q qpgy7  
} PD&\LbuG  
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public String getSFilePath() U1DXeh~V  
{ lD^]\;?  
return sFilePath; ROg(U8 N  
} 0f

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public void setSFilePath(String value) C\/xl#e<@  
{ co~Pyj  
sFilePath = value; :=/85\P0SU  
} i@P)a'W_  
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@
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public String getSFileName()
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{ b8V~S'6VqO  
return sFileName; tZ} v%3  
} o7J  
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public void setSFileName(String value) 1Ty<\bZ=  
{ DF1I[b=]  
sFileName = value; NLUT#!Gr  
} P|.]DJ  
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public int getNSplitter() uJFdbBDSh  
{ fBRo_CU8!  
return nSplitter; 4]h =yc R  
} $ et0s;GBv  
J)`-+}7$v  
f|h|q_<;  
public void setNSplitter(int nCount) :n0vQ5a  
{ h\5OrD@L  
nSplitter = nCount; k5D%y3|9  
} (@%gS[]  
} V.O(S\  
:p]'32FA!  
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/* [`^a=:*  
**Utility.java ,_Z5m;  
*/ POdUV  
package NetFox; N['qgO/  
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public class Utility { @\|_  
R_sr?V|"  
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public Utility() k.uMp<)D  
{ RRRCS]y7$t  
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} 0Uo\wyd  
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//线程睡眠 AWP"b?^G|  
public static void sleep(int nSecond) ]|MEx{BG-  
{ .Xce9C0SW  
try{ ( M7pT  
Thread.sleep(nSecond); x|mqL-Q f  
} Z @^9PQG$  
catch(Exception e) J3n-`k8  
{ ]}U*_rM:  
e.printStackTrace (); JsDpy{q  
} X:6c}p%,!  
} &?q/1vLa  
*MJX?  
//日志 _59huC.  
public static void log(String sMsg) kPVO?u
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{ LL2=&VK  
System.err.println(sMsg); 8g&? Cc  
} kKAP"
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Zrvz;p@~  
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public static void log(int sMsg) MC<PM6w  
{ _(h&7P9  
System.err.println(sMsg); zx-81fx+k  
} \De{9v  
} c- }X_)U }  
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V
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/* 8ELCs<xI  
**TestMethod.java s
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*/ TMig-y*[  
package NetFox; %KmiH ;U  
u/M+u;  
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public class TestMethod { |962G1.  
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!Cr(Pe]  
public TestMethod() $4/yZaVb  
{ ///xx/weblogic60b2_win.exe .u4 W /  
try{ ig/%zA*Bo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .Yf:[`Q6g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VxV
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SiteFileFetch fileFetch = new SiteFileFetch(bean);  #`o2Z  
fileFetch.start(); qNYN-f~@,  
} 4"(<X  
catch(Exception e){e.printStackTrace ();} <$X3Hye  
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} CitDm1DXt/  
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public static void main(String[] args) 6"~P/\jP  
{ F;+|sMrq  
new TestMethod(); @ Wd9I;hWv  
} *T5!{  
} w]]8dz  
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