http断点续传简单实现（java)

/* > 84e`aGE  
**SiteFileFetch.java Q*gnAi&.#  
*/ D>P;Izb  
package NetFox; 0}B?sNr  
import java.io.*;  Q.yb4  
import java.net.*; k=e`*LB\  
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public class SiteFileFetch extends Thread { /^Y[*5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6;gLwOeOHY  
long[] nStartPos; //开始位置 1t.R+1[c  
long[] nEndPos; //结束位置 6Z Xu,ks}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $|k%@Q>  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 z?)He)d  
boolean bStop = false; //停止标志 ^CUSlnB\(  
File tmpFile; //文件下载的临时信息 )#a7'Ba  
DataOutputStream output; //输出到文件的输出流 7SaiS_{:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0Q7MM6  
public SiteFileFetch(SiteInfoBean bean) throws IOException sdrWOq  
{ )AI?x@  
siteInfoBean = bean; "TfI+QgLF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !~)90Z!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u\f3qc,]F  
if(tmpFile.exists ()) B_hPcmB  
{ d.p'pGL  
bFirst = false;  c-5Ysg  
read_nPos(); =5?.'XMk  
} `%Q&</X  
else 6AAswz'$P  
{ >VP5vkv=  
nStartPos = new long[bean.getNSplitter()]; b:1 L@8s;  
nEndPos = new long[bean.getNSplitter()]; dq(E&`SzK  
} UU[H@ym
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} -G-3q
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public void run() ~g7m3  
{ KzNm^^#/$A  
//获得文件长度 { D+Ym%n  
//分割文件 w.z<60%},0  
//实例FileSplitterFetch ^^U%cuKg  
//启动FileSplitterFetch线程 !>3LGu,  
//等待子线程返回 ;}K62LSR  
try{ 6J\fF tB@V  
if(bFirst) >La><.z~  
{ q(Hip<6p  
nFileLength = getFileSize(); ,5{$+  
if(nFileLength == -1) 'C
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{ p?JQ[K7i  
System.err.println("File Length is not known!"); GJ,aRI  
} 'OD)v  
else if(nFileLength == -2) L=]p_2+  
{ xzr<k S
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System.err.println("File is not access!"); at| \FOKj  
} t"|DWC*  
else -uj3'g(;w  
{ |cgui  
for(int i=0;i<nStartPos.length;i++) cS(;Qs]Q  
{ G>K@AW#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0e16Ow6\!1  
} DW>ES/B8$(  
for(int i=0;i<nEndPos.length-1;i++) [EOVw%R  
{ 8I.VJ3Q  
nEndPos = nStartPos[i+1]; ,F9nDF@)  
} &I/qG`W  
nEndPos[nEndPos.length-1] = nFileLength; ugLlI2 nJ  
} Gq1)1  
} )M:)y  
;&S;%W>|  
 q=4Bny0  
//启动子线程 Q|c|2byb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i%F<AY\O)  
for(int i=0;i<nStartPos.length;i++) ?:uNN  
{ VD[pZ2;4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "VTF}#Uo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  z)w-N  
nStartPos,nEndPos,i); :G=FiC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y' [LNp V  
fileSplitterFetch.start(); cU8xUpq  
} ||Y<f *  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~=cmM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S&wzB)#'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S-c ^eLzQ  
nEndPos = " + nFileLength); }`_(<H  
// fileSplitterFetch[nPos.length-1].start(); 2hq\n<  
>;9NtoE  
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//等待子线程结束 T$P-<s  
//int count = 0; 5JSrrpGr
 
//是否结束while循环 y vI<4F  
boolean breakWhile = false; "@yyXS r  
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while(!bStop) D(\$i.,b2  
{ Bm/
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write_nPos(); r,;\/^u*  
Utility.sleep(500); xaW{I7FfG  
breakWhile = true; i=rH7k  
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for(int i=0;i<nStartPos.length;i++) pj8azFZ  
{ g7n"  
if(!fileSplitterFetch.bDownOver) VaR/o#  
{ E!mmLVa9  
breakWhile = false; b1-&v|L  
break; k\aK?(.RC7  
} <]U1\~j  
} izwUS!5e  
if(breakWhile) *C2R`gpBI  
break; {HrZ4xQnpV  
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)(TAT<  
//count++; G;1?<3
 
//if(count>4) uQ3[Jz`y  
// siteStop(); orfp>B) 0  
} <Ef[c@3  
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System.err.println("文件下载结束！"); lr3mE  
} d%ME@6K)  
catch(Exception e){e.printStackTrace ();} nc?B6IV  
} lm0N5(XP  
{' 5qv@3  
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//获得文件长度 5v _P Oq  
public long getFileSize() fZ{[]dn[  
{ $>q@SJ1q  
int nFileLength = -1; !#N\b  
try{ c0rk<V%5+  
URL url = new URL(siteInfoBean.getSSiteURL()); m9":{JI.w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Im?LIgt$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'EhBRU%  
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int responseCode=httpConnection.getResponseCode(); DuF"*R~et  
if(responseCode>=400) m_7 nz!h  
{ dh -,E  
processErrorCode(responseCode); <02m%rhuW  
return -2; //-2 represent access is error qJv[MBjk3B  
} ] d?x$>  
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String sHeader; #R&H&1  
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for(int i=1;;i++) ^@6q  
{ PK2~fJB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E"PcrWB&  
//Utility.log(in.readLine()); Xm!-~n@-m7  
sHeader=httpConnection.getHeaderFieldKey(i); *?% k
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if(sHeader!=null) egR-w[{  
{ !8RwO%c(  
if(sHeader.equals("Content-Length")) tWPO]3hW  
{ <L0#O(L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r4XH =  
break; G| m4m.  
} 5iX! lAFJ  
} ~)]} 91p  
else m$2<`C=  
break; q1{H~VSn"  
} .*/Fucr  
} nk=$B(h  
catch(IOException e){e.printStackTrace ();} 5.0e~zlM-  
catch(Exception e){e.printStackTrace ();} elPE%'  
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Utility.log(nFileLength); CA s>AXbs  
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return nFileLength; Ey`h1Y  
} Gc,_v3\  
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//保存下载信息（文件指针位置） XNH4vG |  
private void write_nPos() NL"G2[e  
{ !{%:qQiA  
try{ $j
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output = new DataOutputStream(new FileOutputStream(tmpFile)); hZ$t$3  
output.writeInt(nStartPos.length); A[N{  
for(int i=0;i<nStartPos.length;i++) 0 p
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{ j<yiNHC  
// output.writeLong(nPos); P 7D!6q  
output.writeLong(fileSplitterFetch.nStartPos); F7}-!  
output.writeLong(fileSplitterFetch.nEndPos); _e<o7Y@_  
} MgMD\  
output.close(); lS5ny  
} b^CNVdo'  
catch(IOException e){e.printStackTrace ();} L"(4R^]  
catch(Exception e){e.printStackTrace ();} 
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} D-p.kA3MJ  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() (P|pRVO  
{ V9%aBkf8w  
try{ ?&+9WJ<M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :!TIK1  
int nCount = input.readInt(); M[]A2'fS  
nStartPos = new long[nCount]; 5"KlRuv%  
nEndPos = new long[nCount]; 2umv|]n+l|  
for(int i=0;i<nStartPos.length;i++) v3[@1FQ"  
{ \,G#<>S  
nStartPos = input.readLong(); iw?I  
nEndPos = input.readLong(); Tl("IhkC  
} 5TKJWO.  
input.close(); OjE`1h\  
} OS-f(qXd+  
catch(IOException e){e.printStackTrace ();} 3`.P'Fh(k  
catch(Exception e){e.printStackTrace ();}
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} :D:DnVZ-[@  
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private void processErrorCode(int nErrorCode) N:5[,O<m_  
{ |UUdz_i!:  
System.err.println("Error Code : " + nErrorCode); ))h6~1`  
} S=|@L<O  
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//停止文件下载 ?}QH=&=^  
public void siteStop() 8(U{2B8>\%  
{ oMH.u^b]fT  
bStop = true; cI0 ]}S  
for(int i=0;i<nStartPos.length;i++) z_|oCT!6  
fileSplitterFetch.splitterStop(); \_6OCVil  
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} mu]as: ~  
} k=ytuV\  
//负责部分文件的抓取 S_(d9GK<  
**FileSplitterFetch.java '-$XX%TOAc  
*/ ]3{0J  
package NetFox; !RvRGRSyF  
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import java.io.*; =3xE:  
import java.net.*; 7*o*6,/  
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public class FileSplitterFetch extends Thread { <i\A_qqc/  
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String sURL; //File URL ~:4kU/]  
long nStartPos; //File Snippet Start Position yBpk$  
long nEndPos; //File Snippet End Position u
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int nThreadID; //Thread's ID "8f?h%t  
boolean bDownOver = false; //Downing is over j V3)2C}  
boolean bStop = false; //Stop identical h!@,8y[B  
FileAccessI fileAccessI = null; //File Access interface JtKp(k&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PG%0yv%  
{ R{YzH56M  
this.sURL = sURL; IXLO
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this.nStartPos = nStart; +FG$x/\*0  
this.nEndPos = nEnd; NcS.49  
nThreadID = id; ;Y9=!.Ak0y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zk_Eb?mhwV  
} :Sg&0Wj+#j  
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public void run() gO?44^hMe  
{ @LE[ac  
while(nStartPos < nEndPos && !bStop) h+~P"i}&\  
{ K-vWa2  
d
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M5L{*>4|6  
try{ |H}sYp  
URL url = new URL(sURL); 66&EBX}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q}|U4MJm  
httpConnection.setRequestProperty("User-Agent","NetFox"); M+>`sj  
String sProperty = "bytes="+nStartPos+"-";  %V G/  
httpConnection.setRequestProperty("RANGE",sProperty); b]Kk2S/  
Utility.log(sProperty); 6(&Y(/  
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InputStream input = httpConnection.getInputStream(); YB))S!;Ok  
//logResponseHead(httpConnection); ^WYQ]@rh3  
I_)*)d44_  
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byte[] b = new byte[1024]; +Lm4kA+aE5  
int nRead; 'Ye v}QM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rsNf$v-*  
{ J:dof:q  
nStartPos += fileAccessI.write(b,0,nRead); or*HC&c7  
//if(nThreadID == 1) =v~1qWX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %
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} _o6G6e,  
^ZeJ[t&!#  
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Utility.log("Thread " + nThreadID + " is over!"); f|EUqu%E  
bDownOver = true; 
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//nPos = fileAccessI.write (b,0,nRead); \{\MxXW  
} hn)a@  
catch(Exception e){e.printStackTrace ();} rZ1Hf11C  
} !cW[G/W8  
} k_|^kdWJ  
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//打印回应的头信息 .lG5=Th!
 
public void logResponseHead(HttpURLConnection con) \t4tiCw  
{ Z
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for(int i=1;;i++) H[Q_hY[>V  
{ r`\A nT?  
String header=con.getHeaderFieldKey(i); 1$lh"fHU  
if(header!=null) h[tix:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -<_$m6x"A  
Utility.log(header+" : "+con.getHeaderField(header)); a~LC+8|JW  
else @DAF 6ygs  
break; E:E4ulak  
} 0[A9b,MMVO  
} (P|~>k  
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public void splitterStop() ,{eUP0]  
{ w)]H ^6  
bStop = true; 4 {GU6v)f  
} 4\5uY  
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} f7de'^t9  
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/* \kamcA  
**FileAccess.java )U<Y0bZA!
 
*//文件访问(定位，写) `D5HC  
package NetFox; I3S9Us-\  
import java.io.*; ?NNn:tiD  
._:nw=Y0<}  
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public class FileAccessI implements Serializable{ f3*?MXxb16  
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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 /(C~~XP)  
RandomAccessFile oSavedFile; +?D6T!
)  
long nPos; qf)$$qi  

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public FileAccessI() throws IOException ra '  
{ ,hxkk`  
this("",0); \[2lvft!  
} $gle8Z-  
>?W[PQ5yx  
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public FileAccessI(String sName,long nPos) throws IOException @+,pN6}g  
{ L];y}]:F*  
oSavedFile = new RandomAccessFile(sName,"rw"); [f~N_G6I^o  
this.nPos = nPos; o/cjXun*  
oSavedFile.seek(nPos); ^,Ydr~|T  
} <oMUQ*OtV  
4B+9z^oQ  
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public synchronized int write(byte[] b,int nStart,int nLen) $WQq?
1.9  
{ 4IdT'  
int n = -1; vm23U^VJ  
try{ O!1Tth
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oSavedFile.write(b,nStart,nLen); 9X<OJT;3J  
n = nLen; ;)0w:Zn/[  
} PG5- ;i/  
catch(IOException e) 0pe3L  
{ +0z 7KO%^^  
e.printStackTrace (); d?,M/$h  
} _+f+`]iM  
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return n; N^?9ZO  
} Wk;5/  
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} wYsZM/lw  
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/* i@"e,7mSG  
**SiteInfoBean.java <pLT'Y=  
*/ gW(gJ; L,%  
package NetFox; |Yi)"-  
#:fQ.WWO  
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public class SiteInfoBean { DR9: _  
Si}HX!s  
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private String sSiteURL; //Site's URL I{0k  
private String sFilePath; //Saved File's Path ^S)TO
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private String sFileName; //Saved File's Name [(LV
  
private int nSplitter; //Count of Splited Downloading File (3vHY`9  
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public SiteInfoBean() 0CvsvUN@  
{//nSplitter的缺省值为5 z T%U!jqI  
//default value of nSplitter is 5 yTM{|D]$(  
this("","","",5); L7Dh(y=;7  
} .?C%1a&_l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "T/>d%O1b  
{ lw%?z/HDf  
sSiteURL= sURL; 8am`6;O:!  
sFilePath = sPath; dmrps+L  
sFileName = sName; `A%^UCd  
this.nSplitter = nSpiltter; 9e!NOl\_;.  
5@osnf?  
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} -!qu"A:  
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public String getSSiteURL() K5Wg"^AHY/  
{ I lR\  #  
return sSiteURL; ?gGt2O1J  
} ,M !tm7  
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?:  
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public void setSSiteURL(String value) 6bc337b  
{ 1a0kfM$  
sSiteURL = value; RH0>ZZR  
} c2l_$p  
!%mAh81{&/  
s,VXc/  
public String getSFilePath() |8_JY2 R  
{ UAS@R`?
cI  
return sFilePath; Y+%sBqo@  
} ]6Ug>>x5  
zkM"cb13q/  
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public void setSFilePath(String value) C=Fzu&N}  
{ `WEZ"5n  
sFilePath = value; *TW=/+j  
} KP;(Q+qTx  
Uh}seB#mJj  
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public String getSFileName() PrQ?PvA<L  
{ vEM(bT=H  
return sFileName; Zx }&c |Q  
} Z]w#vL
R  
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public void setSFileName(String value) {'+QH)w(  
{ z"4]5&3A  
sFileName = value; XK(`mEi  
} +KGZHO!  
=]R3& ]#n  
V
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public int getNSplitter() MWk:sBCqr  
{ ;#GoGb4AM  
return nSplitter; jd`},X/  
} S&C1TC  
X8eJ4%  
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public void setNSplitter(int nCount) GnXNCeE`  
{ ivgpS5 M`Y  
nSplitter = nCount; ajl 2I/D  
} ChryJRuwv5  
} Bc-yxjsw  
SZ![%)83  
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j  
/* v<\A%  
**Utility.java " }gVAAvc7  
*/ q}uHFp/J  
package NetFox; W_O)~u8  
a\uie$"cr]  
3 vP(SIF  
public class Utility { 5M]z5}n/  
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public Utility() Ax3W2s  
{ et,GrL)l  
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} `;,Pb&
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p_*M:P1Ma4  
//线程睡眠 ~d{.ng 4K  
public static void sleep(int nSecond) f"#m=_Xm  
{ ? ]sM8Bd}  
try{ 7fp(R&)1  
Thread.sleep(nSecond);  c9''  
} x)rlyjFM  
catch(Exception e) ~cAZB9Fa  
{ ub0zJTFJ#  
e.printStackTrace (); k@>\LR/v  
} yDb'7(3-  
}
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//日志 |6:=}dE#[  
public static void log(String sMsg) $$i.O}  
{ _fFU#k:MU  
System.err.println(sMsg); 7x]4`#u  
} Sydh2d  
,7Y-k'7Kop  
a~h:qpgc  
public static void log(int sMsg) Dq\ Jz~  
{ V{-AP=C7  
System.err.println(sMsg); n;HHogA  
} r,SnXjp@  
} 8GPIZh'0h  
c;f!!3&  
Z!d7&T}  
/* =+5,B\~q@C  
**TestMethod.java ,?UM;^  
*/ Eu}b8c  
package NetFox; 5/",<1  
6[qA`x#  
1L7{p>;-dO  
public class TestMethod { C<^YVeG  
D\~zS`}  
}F6<w{|  
public TestMethod() EO|:
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{ ///xx/weblogic60b2_win.exe 9Ywpej*+  
try{ JuRH>`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pnyWcrBf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (w(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %U7.7dSOI;  
fileFetch.start(); -b&{+= ^c  
} v7  
catch(Exception e){e.printStackTrace ();} 4P
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} $aCd/&  
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public static void main(String[] args) g3n'aD@'x  
{ m8Vdb"0  
new TestMethod(); Y&H}xn  
} 2N#$X'8  
} <%}QDO8\i  
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