http断点续传简单实现（java)

/* *B|hRZka1A  
**SiteFileFetch.java yQrgOdo,w  
*/ $\P/ %eP  
package NetFox; 1yE',9?  
import java.io.*; XS&Pc  
import java.net.*; 3%)cUkD  
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public class SiteFileFetch extends Thread { HKJCiQ|k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ExO#V9DaW  
long[] nStartPos; //开始位置 w
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long[] nEndPos; //结束位置 IE\RP!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \ZcI{t'a  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 ~},H+A!?  
boolean bStop = false; //停止标志 */K[B(G  
File tmpFile; //文件下载的临时信息 @JlT*:Dz  
DataOutputStream output; //输出到文件的输出流 i<Ms2^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） HHx:s2G  
public SiteFileFetch(SiteInfoBean bean) throws IOException !b`fykC  
{ Zl3l=x h  
siteInfoBean = bean; la{?
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); = cxO@Fu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U[pHT _U  
if(tmpFile.exists ()) 2*D2jw  
{ F4\:9ws  
bFirst = false; ']2Vf]dB  
read_nPos(); z!6_u@^-  
} -"xAeI1+  
else hXI[FICQU{  
{ %@:>hQ2;  
nStartPos = new long[bean.getNSplitter()]; X40gJV<  
nEndPos = new long[bean.getNSplitter()]; `S((F|Ty=;  
} l)$mpMgAD  
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} =M 8Mt/P  
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public void run() ;0WAfu}#H  
{ <T7@,_T  
//获得文件长度 S<]k0bC  
//分割文件 Ia](CN*;6  
//实例FileSplitterFetch DH\Ox>b=  
//启动FileSplitterFetch线程 w31O~Ve  
//等待子线程返回 aN"
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try{ LeN }Q  
if(bFirst) TgV-U  
{ ?5">50  
nFileLength = getFileSize(); \_.'/<aQ  
if(nFileLength == -1) mL1ZSX o!  
{ 1R-0b{w[  
System.err.println("File Length is not known!"); 1W*Qc_5 v1  
} ]Yt3@ug_f  
else if(nFileLength == -2) gs1  
{ |6-9vU!LK?  
System.err.println("File is not access!"); 60~*$`  
} /w dvm4  
else Nkb%4ofKqu  
{ w#9.U7@.  
for(int i=0;i<nStartPos.length;i++) f|~'(~Sr  
{ =X'EDw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;woK96"{t  
} 1Mq"f7X8  
for(int i=0;i<nEndPos.length-1;i++) suQ`a_zJ  
{ KUX6n(u  
nEndPos = nStartPos[i+1]; L' _%zO  
} q#Otp\f  
nEndPos[nEndPos.length-1] = nFileLength; q:up8-LAr  
} !pe[H*Cy  
} XKp(31])  
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//启动子线程 8u[.s`^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b7xOm"X,N  
for(int i=0;i<nStartPos.length;i++) >*/ |tL  
{ f(}&8~&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \W_ Dz*N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ++w{)Io Z  
nStartPos,nEndPos,i); ~+ae68{p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U'b}%[  
fileSplitterFetch.start(); LkeYzQH/l  
} xg%{p``  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B7A.~'=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :zC=JvKT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MeV4s%*O+  
nEndPos = " + nFileLength); i{:?Iw 'ay  
// fileSplitterFetch[nPos.length-1].start(); 3|e~YmZx  
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:;#^gvH  
//等待子线程结束 *>iJ=H  
//int count = 0; !b
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//是否结束while循环 fX:G;vYn  
boolean breakWhile = false; Lo'G
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while(!bStop) %xx;C{g;a  
{ vRmzj
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write_nPos(); !N:w?zsp  
Utility.sleep(500); HU +271A8  
breakWhile = true; %D7^.  
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for(int i=0;i<nStartPos.length;i++) ,iiI5FR  
{ RionKi
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if(!fileSplitterFetch.bDownOver) 4wS!g10}  
{ pdQaVe7tRo  
breakWhile = false; *JW.ca}  
break; 2#`d:@r  
} I`{=[.c  
} ,^iT,MgNNf  
if(breakWhile) 99zMdo S  
break; 10dK%/6/O  
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//count++; EA:_PBZ  
//if(count>4) Dxr4B<  
// siteStop(); q<g!bW%  
} 1{xkAy0  
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System.err.println("文件下载结束！"); @$ )C pg  
} i[U=-4 J  
catch(Exception e){e.printStackTrace ();} cJ,`71xop,  
} "g!/^A!!  
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//获得文件长度 /{ 8.Jcx$  
public long getFileSize() )]}68}9  
{ =:RNpi,  
int nFileLength = -1; :d~&Dt<c  
try{ x6yO2Yo  
URL url = new URL(siteInfoBean.getSSiteURL()); ,l)AYu!q4F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k"`^vV[{F  
httpConnection.setRequestProperty("User-Agent","NetFox"); (yeN> x}_  
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int responseCode=httpConnection.getResponseCode(); H#`&!p  
if(responseCode>=400) ~bjT,i  
{ y3 S T"U  
processErrorCode(responseCode); |R Qa.^.  
return -2; //-2 represent access is error .w~L0(  
} 1rmN)  
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String sHeader; F.R0c@&W  
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for(int i=1;;i++) tUFXx\p  
{ (5^SL Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <,'^dR7,  
//Utility.log(in.readLine()); j62oA$z  
sHeader=httpConnection.getHeaderFieldKey(i); ~qW"v^<  
if(sHeader!=null) Gc!&I+kd  
{ '^t(=02J  
if(sHeader.equals("Content-Length")) 2f0_Xw_V_  
{ |i'w"Tz4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ef6LBNWY.  
break; hniT
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} qQ<7+z<4KP  
} ]n|lHZR  
else ,6\oT;G  
break; Mw$.B#  
} ?Qh[vcF7`  
} SL% Ec%9Y  
catch(IOException e){e.printStackTrace ();} h6gtO$A|p=  
catch(Exception e){e.printStackTrace ();} ]FO)U  
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Utility.log(nFileLength); {$-\)K  
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return nFileLength; 1\Vp[^
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} !%yd'"6Dl  
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//保存下载信息（文件指针位置） (@u"  
private void write_nPos() v%2Jm!i+  
{ o7 X5{  
try{ T;JA.=I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,Z]4`9c  
output.writeInt(nStartPos.length); g(zoN0~  
for(int i=0;i<nStartPos.length;i++) WO6;K]  
{ h|&qWv  
// output.writeLong(nPos); <3aW3i/jTc  
output.writeLong(fileSplitterFetch.nStartPos); X1~ B  
output.writeLong(fileSplitterFetch.nEndPos); a{8g9a4  
} 8U&93$  
output.close(); `wLa.Gzj  
} J|I&{  
catch(IOException e){e.printStackTrace ();} e;)&Hc:Z  
catch(Exception e){e.printStackTrace ();} ,n+~S^r  
} E@$HO_;&  
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//读取保存的下载信息（文件指针位置） |zSoA=7?  
private void read_nPos() <DM:YWNa  
{ i/WiSwh:  
try{ g JMv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c1Ta!p{%  
int nCount = input.readInt(); xu0pY(n^r  
nStartPos = new long[nCount]; T$;N8x[  
nEndPos = new long[nCount]; IGtqY8  
for(int i=0;i<nStartPos.length;i++) `]:&h'  
{ 5%Q[X  
nStartPos = input.readLong(); wN
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nEndPos = input.readLong(); #>\+6W17U  
} }7jg>3ng(  
input.close(); WKPuIE:  
} G_a//[p  
catch(IOException e){e.printStackTrace ();} ?rgk  
catch(Exception e){e.printStackTrace ();}  =:-x;  
} @z)_m!yV1  
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*
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private void processErrorCode(int nErrorCode) !EQMTF=(  
{ 9fL48
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System.err.println("Error Code : " + nErrorCode); PH}^RR{H[  
} ;MR(Ea
ep  
 "Aq-H g  
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//停止文件下载 0vRug|}k#%  
public void siteStop() &N!;d E  
{ U0:tE>3`  
bStop = true; =,=tSp  
for(int i=0;i<nStartPos.length;i++) i`1QR@11  
fileSplitterFetch.splitterStop(); A[6$'IJ  
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} w<]Wg^dyQ  
} 5b9>a5j1;  
//负责部分文件的抓取 qeyBZ8BG  
**FileSplitterFetch.java f`jRLo*L  
*/ i+V4_`  
package NetFox; Rz!E=1Y$  
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import java.io.*; ;?9u#FRtw  
import java.net.*; WBA0! g98  
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public class FileSplitterFetch extends Thread { 4V7{
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String sURL; //File URL ,!f*OWnZ  
long nStartPos; //File Snippet Start Position TWC^M{e  
long nEndPos; //File Snippet End Position S)[`Bm  
int nThreadID; //Thread's ID `bGAc&,&  
boolean bDownOver = false; //Downing is over H5Rn.n(|  
boolean bStop = false; //Stop identical JeJ
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FileAccessI fileAccessI = null; //File Access interface =^P<D&%q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t`DoTb4  
{ pbivddi2  
this.sURL = sURL; {O
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this.nStartPos = nStart; ;fhFv&`mE  
this.nEndPos = nEnd; `n7z+  
nThreadID = id; bgd1j,PWbW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Got5(^'c  
} o_<o8!]l"  
#nc{MR#R  
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public void run() }@V(y
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{ X;T(?,,  
while(nStartPos < nEndPos && !bStop) :JqH.Sqk  
{ ,|b<as@X  
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try{ abtAkf  
URL url = new URL(sURL); @R?S-*o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QhK]>d.  
httpConnection.setRequestProperty("User-Agent","NetFox"); `,&h!h((  
String sProperty = "bytes="+nStartPos+"-"; fw_V'l#\  
httpConnection.setRequestProperty("RANGE",sProperty); PKu+$  
Utility.log(sProperty); b:>(U.   
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InputStream input = httpConnection.getInputStream(); `7Ni bZX0  
//logResponseHead(httpConnection); dKw*L|5  
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byte[] b = new byte[1024]; :t]YPt
  
int nRead; -ny[Lh^b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $CO^dFf  
{ U\y];\~H  
nStartPos += fileAccessI.write(b,0,nRead); [[?:,6I  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b IcLMG s  
}
}(dhXOf\q  
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Utility.log("Thread " + nThreadID + " is over!"); Rw*l#cr=.  
bDownOver = true; S(Xab_DT)H  
//nPos = fileAccessI.write (b,0,nRead); by&#g  
} H(!)]dO  
catch(Exception e){e.printStackTrace ();} waW2$9O  
} }V?SedsY  
} _odP:  
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//打印回应的头信息 Q! ]  
public void logResponseHead(HttpURLConnection con) 4)-LlYS_d<  
{ G1vWHa7n;f  
for(int i=1;;i++) oKiBnj5J  
{ wnP#.[,V  
String header=con.getHeaderFieldKey(i); c{6!}0Q4  
if(header!=null) 8,#v7ns}#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g` 6Xrf  
Utility.log(header+" : "+con.getHeaderField(header)); a{QHv0goG  
else [(5;jUmF@  
break; 'AE)&56  
} 'u{m37ZJ  
} q*\#HC  
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public void splitterStop() IR?ICXmtx  
{ T#Qn\8  
bStop = true; .:*V CDOM  
} g9H~\w  
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} DT8|2"H  
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/* >o>r@;  
**FileAccess.java ny|ni\6  
*//文件访问(定位，写) Xlpu_H|  
package NetFox; 4$+1jjC]>~  
import java.io.*; 8=FP92X  
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public class FileAccessI implements Serializable{ 0"(5\T  
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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 PCH&eTKN  
RandomAccessFile oSavedFile; u{,e8. Z  
long nPos; **d3uc4y  
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public FileAccessI() throws IOException ^<'5 V)  
{ Y'&A~/Adf  
this("",0); `=RJ8u  
} Qa~o'  
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rJ4O_a5/  
public FileAccessI(String sName,long nPos) throws IOException Igt:M[ /  
{ fD  
oSavedFile = new RandomAccessFile(sName,"rw"); YQvN;W  
this.nPos = nPos; y~w2^VN=  
oSavedFile.seek(nPos); Ra}%:  
} \C5YVl#  
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public synchronized int write(byte[] b,int nStart,int nLen) 3*"
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{ ^\Nsx)Y;  
int n = -1; 'due'|#^  
try{ !jL|HwlA  
oSavedFile.write(b,nStart,nLen); v=EV5#A  
n = nLen; 8bLA6qmM\  
} Jiyt,D*wX  
catch(IOException e) "ys#%,Z  
{ :3M2zV cf  
e.printStackTrace (); uV!Ax*'  
} NK2Kw{c"iI  
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return n; >j5) MF{"  
} NBuib
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} hqIYo .<  
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/* kNP.0  
**SiteInfoBean.java j}7as&  
*/ i_Dv+^&zV  
package NetFox; FtXd6)_S  
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public class SiteInfoBean { _xT=AF9~o  
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private String sSiteURL; //Site's URL Oa~|a7`o  
private String sFilePath; //Saved File's Path 1ThONrxu  
private String sFileName; //Saved File's Name X~|P  
private int nSplitter; //Count of Splited Downloading File ):OGhW
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public SiteInfoBean() m99j]wr~c  
{//nSplitter的缺省值为5 Rj 2N+59rg  
//default value of nSplitter is 5 2g5Ft  
this("","","",5); t)P5bQ+$u9  
} 7Gb1[3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BayO+,>K
 
{ ;AMbo`YK[  
sSiteURL= sURL; os6p1"_\f  
sFilePath = sPath; I;H6E  
sFileName = sName; d#
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this.nSplitter = nSpiltter; CBw/a0Uck  
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} 4np,"^c  
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public String getSSiteURL() 8:^`rw4a0  
{ zy\p,  
return sSiteURL; YoiM
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} V#8]io  
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public void setSSiteURL(String value) \pI)tnu6'U  
{ NX7(;02  
sSiteURL = value; w{uqy]  
} \l!^6G|c  
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public String getSFilePath() Y@x }b{3  
{ ]-h$CJSY  
return sFilePath; fFP>$  
} T \%{zz_(  
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public void setSFilePath(String value) [U+6Tj,  
{ fy|ycWW>8  
sFilePath = value; ^Q!qJav  
} 6&/H XqP  
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public String getSFileName() ?^]29p_  
{ &atT7m  
return sFileName; hnWo.5;$  
} Ar&]/X,WG  
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=
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public void setSFileName(String value) MQ;c'?!5[!  
{ jP'.a. ^o$  
sFileName = value; xK4b(KJj  
} hKq <e%oVH  
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public int getNSplitter() c%1<O!c  
{ zTi%j$o  
return nSplitter; _r!''@B  
}
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public void setNSplitter(int nCount) #PYTFB%  
{ 'Y23U7 n0B  
nSplitter = nCount; HfN-WYiR  
} J/(3: a>  
} v=Ep
  
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/* dRg1I=|{_  
**Utility.java s=`1wkh0  
*/ y7M"Dr%t^  
package NetFox; 12)~PIaF  
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public class Utility { #5HJW[9  
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public Utility() %XGwQB$zk8  
{ xQs2)  
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} kE QT[Lo  
@ -pi  
//线程睡眠 061@N=p8  
public static void sleep(int nSecond) _$/(l4\T[  
{ W&`_cGoP  
try{ ^!^8]u<Q  
Thread.sleep(nSecond); `WF?87l1  
} r-]Au -  
catch(Exception e) jM1|+o*Wr  
{ V/i&8UMw  
e.printStackTrace (); N(mhg
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} Vf6lu)Zc1  
} 7]a6dMh  
"^~f.N  
//日志 ]t_AXKd  
public static void log(String sMsg) Nb\4Mv`  
{ `.nkC_d  
System.err.println(sMsg); p"ht|x  
} SFKW"cP  
%b'ic  
95^w" [}4Q  
public static void log(int sMsg) [~?LOH  
{ ?sDm~]Z  
System.err.println(sMsg); Rj9ME,u  
} 0wXfu"E{  
} ^Qz8`1`;Z  
#B:J7&@fn  
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/* VcIsAK".4[  
**TestMethod.java :6PWU$z$7  
*/ w(n&(5FzB<  
package NetFox; y.5mYQA4=[  
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public class TestMethod {
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]"q[hF*PM  
public TestMethod() ;Avd$&::  
{ ///xx/weblogic60b2_win.exe +pc_KR  
try{ G+AD &EHV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BIDmZU9tL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WaF<qhu*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -vwkvNn8  
fileFetch.start(); "cRc~4%K  
} B`<(qPD  
catch(Exception e){e.printStackTrace ();} =PAvPj&}e  
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cEi{+rfZd|  
} ,%mTKOs  
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public static void main(String[] args) xZPSoxu  
{ @no]*?Gpa  
new TestMethod(); %m!o#y(hD`  
} h1G]w/.ws  
} i;*c|ma1>  
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