http断点续传简单实现（java)

/* ^m7PXY  
**SiteFileFetch.java Nf~<xK  
*/ o]j*  
package NetFox; O| 2Q- @D  
import java.io.*; _Dv^~e1c  
import java.net.*; ppYz~ {"r  
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public class SiteFileFetch extends Thread { 0Nfj}sXCWE  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'ZDclz9}  
long[] nStartPos; //开始位置 _`\INZe-G  
long[] nEndPos; //结束位置 tEUmED0FY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 VuY.})+J:  
long nFileLength; //文件长度 kmS8>O  
boolean bFirst = true; //是否第一次取文件 ev3x*}d0  
boolean bStop = false; //停止标志 wfdFGoy(  
File tmpFile; //文件下载的临时信息 F~Li.qF  
DataOutputStream output; //输出到文件的输出流 pA2U+Q@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |bk*Lgkzw  
public SiteFileFetch(SiteInfoBean bean) throws IOException U!5@$Fu  
{ anvj{1  
siteInfoBean = bean; @.{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A_.QHUjpx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2*|]#W
 
if(tmpFile.exists ()) UdGoPzN  
{ \x!>5Z Y  
bFirst = false; LWI~m2  
read_nPos(); Hj!)S&y,$  
} D)_Ei'+*l  
else dd$N4&  
{ {G}HZv%S U  
nStartPos = new long[bean.getNSplitter()]; ,uv$oP-  
nEndPos = new long[bean.getNSplitter()]; Q@8[ql1l  
} >W;i2%T  
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} WdT|xf.Q&  
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public void run() <%z/6I Af|  
{ B4}XK=)  
//获得文件长度 q :bKT#\  
//分割文件 ]Q3Gj@6  
//实例FileSplitterFetch 8VZ-`?p  
//启动FileSplitterFetch线程  q0~_D8e,  
//等待子线程返回 p{rS -`I  
try{ .*j+?  
if(bFirst) 2]+.8G7D%  
{ oo!g?X[[  
nFileLength = getFileSize(); 9)">()8  
if(nFileLength == -1) o >Lk`\  
{ US4Um>j  
System.err.println("File Length is not known!"); $ZS9CkN  
} -?W@-*J
 
else if(nFileLength == -2) |6>_L6t  
{ 9zJ`;1  
System.err.println("File is not access!"); %\l,X{X  
} h uJqqC  
else `y}
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{ q8Dwu3D  
for(int i=0;i<nStartPos.length;i++) i7rq;t<  
{ 9QMn%8=j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2An`{')  
} Bt,Xe~$z-  
for(int i=0;i<nEndPos.length-1;i++) R~~rqvLm  
{ =@2V#X]M*  
nEndPos = nStartPos[i+1]; #E9['JnZ
 
} f[b YjIX  
nEndPos[nEndPos.length-1] = nFileLength; T Rw6$CR  
} Aq!['G  
} $J6.a!5IE  
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//启动子线程 ?^~"x.<nr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yUO|3ONT  
for(int i=0;i<nStartPos.length;i++) NJ>p8P`_k  
{ oui!fTy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L2'd
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), prtxE&-  
nStartPos,nEndPos,i); k`TJ<Dv;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (GG"'bYk  
fileSplitterFetch.start(); 2~V Im#  
} >x4[7YAU{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d8HB2c5y0i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n5.>;N.*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", PQ}%}S7:  
nEndPos = " + nFileLength); |lxy< C4V  
// fileSplitterFetch[nPos.length-1].start(); |a{]P=<q  
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au|^V
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//等待子线程结束 It4z9Gh  
//int count = 0; U$)Hhn|X  
//是否结束while循环 L]d@D0.Z  
boolean breakWhile = false; N;'HR)  
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while(!bStop) hXm}
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{ ,
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write_nPos(); m>ycN  
Utility.sleep(500); s&hA  
breakWhile = true; P]"deB|  
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for(int i=0;i<nStartPos.length;i++) </gp3WQ.  
{ AwUc{h l<  
if(!fileSplitterFetch.bDownOver) e({fY.)SGo  
{ S2E HmE&  
breakWhile = false; hw$c@:pW;  
break; JGcD{RU|  
} E[.tQ|C  
} br Z,s  
if(breakWhile) 1~DD9z  
break; 1G%PXrEj8  
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//count++;
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//if(count>4) ]"Y%M'  
// siteStop(); kQVDC,d  
} *frJ^ Ws{  
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System.err.println("文件下载结束！"); =5~F6to  
} M
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catch(Exception e){e.printStackTrace ();} |90 +)/$4  
} =kh>s$We  
>:E*7
 
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//获得文件长度
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public long getFileSize() d-;9L56{P  
{ fu<2t$Cn>  
int nFileLength = -1; `E5"Pmg  
try{ rA1r
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URL url = new URL(siteInfoBean.getSSiteURL()); u=;nU(]M '  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rLh9`0|D  
httpConnection.setRequestProperty("User-Agent","NetFox"); VS|("**  
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int responseCode=httpConnection.getResponseCode(); 0sDwTb"  
if(responseCode>=400) BwJ^_:(p~  
{ 7B]:3M6d  
processErrorCode(responseCode); 1N9<d,  
return -2; //-2 represent access is error D2</^]3Su  
} +Y)#yGUn  
#RM3^]h  
F|l`YtZZd  
String sHeader; x8?x/xE  
5
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for(int i=1;;i++) pzq;vMr  
{ pEVgJ/>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #[a"%byTR  
//Utility.log(in.readLine()); /.)[9bQ<  
sHeader=httpConnection.getHeaderFieldKey(i); -~\.n  
if(sHeader!=null) 6f?BltFaN  
{ 5m^Hi}S_  
if(sHeader.equals("Content-Length")) a-5HIY5
 
{ "f|(@a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pAil]f6  
break; 58&{5YpS  
} 3XwU6M$5g  
} oY%"2PW1B  
else X#DL/#z k  
break; ')5L_$  
} J4G> E.8  
} lMwk.#  
catch(IOException e){e.printStackTrace ();} [.;%\>Qk<  
catch(Exception e){e.printStackTrace ();} Kr/h`RM  
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Utility.log(nFileLength); Fkcx+
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return nFileLength; K)/!&{7n}a  
} U.RW4df%E  
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m\/,cc@,  
//保存下载信息（文件指针位置） `u#;MUg  
private void write_nPos() 9$o<  
{ p9AZ9xr  
try{ ]D LZ&5pv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;h9-}F  
output.writeInt(nStartPos.length); v._Egk0  
for(int i=0;i<nStartPos.length;i++) L/q]QgCoA  
{ ]bTzbu@  
// output.writeLong(nPos); JFRpsv  
output.writeLong(fileSplitterFetch.nStartPos); m']9Q3-  
output.writeLong(fileSplitterFetch.nEndPos); ?aFr8i:)M  
} WVS$O99Y  
output.close(); LBmM{Gu  
} 9DOkQnnc  
catch(IOException e){e.printStackTrace ();} [J)/Et  
catch(Exception e){e.printStackTrace ();} C5es2!^-]O  
} "H>r-cyh  
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//读取保存的下载信息（文件指针位置） m7r j>X Y  
private void read_nPos() ZD5I5  
{ By?nd)  
try{ 7~wFU*P1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P>*Fj4Z~  
int nCount = input.readInt(); -ca7x`yo  
nStartPos = new long[nCount]; .[T'yc:=  
nEndPos = new long[nCount]; %n05Jitl  
for(int i=0;i<nStartPos.length;i++) y]}b?R~p=  
{ }_{y|NW  
nStartPos = input.readLong(); sULIrYRA  
nEndPos = input.readLong(); e9CP802#2  
} ^W Y8-6  
input.close(); kSB  
} #K=b%;>  
catch(IOException e){e.printStackTrace ();} o'C~~Vg).  
catch(Exception e){e.printStackTrace ();} t=n+3`g  
} "jL1.9%"  
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private void processErrorCode(int nErrorCode) )v%l0_z{  
{ z,pNb%*O  
System.err.println("Error Code : " + nErrorCode); 6xH;:B)d  
} fy&#M3UA\U  
&Nc[$H7<  
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//停止文件下载 {(rf/:X!p  
public void siteStop() 7:n?PN(p6a  
{ :KEq<fEI  
bStop = true; SQ}S4r  
for(int i=0;i<nStartPos.length;i++) 5;W\2yj
 
fileSplitterFetch.splitterStop(); 7MY)\aH  
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} Y!SE;N&  
} vqq6B/r@Fu  
//负责部分文件的抓取 Y[W6Sc  
**FileSplitterFetch.java >s&XX, w  
*/ >n]oB~P%  
package NetFox; sffhPX\I  
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import java.io.*; 9Ei5z6Vk/+  
import java.net.*; `9/0J-7*  
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public class FileSplitterFetch extends Thread { ^6Yd}  
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String sURL; //File URL tcZa~3
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long nStartPos; //File Snippet Start Position &=G)NeT_  
long nEndPos; //File Snippet End Position Te# ]Cn|  
int nThreadID; //Thread's ID PPEq6}  
boolean bDownOver = false; //Downing is over d$w(-tV42  
boolean bStop = false; //Stop identical ~i%-WX  
FileAccessI fileAccessI = null; //File Access interface 1\/
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$; ?c?n+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C>^,*7dS  
{ >w9sE8i  
this.sURL = sURL; Q|?'(J+  
this.nStartPos = nStart; W!t{rI72  
this.nEndPos = nEnd; iQq
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nThreadID = id; tww=~!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 alFNSRY  
} le.anJAr  
j !`B'{cH  
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public void run() H( vx/q  
{ /0(%(2jIWl  
while(nStartPos < nEndPos && !bStop) *ot>WVB  
{ @K\o4\  
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try{ H<g 1m  
URL url = new URL(sURL); /jM_mrpz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }`9jH:q-Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?ty>}.c t  
String sProperty = "bytes="+nStartPos+"-"; 2HD:JdL  
httpConnection.setRequestProperty("RANGE",sProperty); q]CeD
 
Utility.log(sProperty); 1w
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InputStream input = httpConnection.getInputStream(); C0QM#"[  
//logResponseHead(httpConnection); k)cP! %
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byte[] b = new byte[1024]; + ~"5!  
int nRead; H(b)aw^(%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jXixVNw  
{ b]T@gJ4H=  
nStartPos += fileAccessI.write(b,0,nRead); YScvyh?E  
//if(nThreadID == 1) eeM?]J-
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8] `Ru5nd  
} 'S*k_vuN  
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Utility.log("Thread " + nThreadID + " is over!"); Lkn4<'un  
bDownOver = true; -jB3L:  
//nPos = fileAccessI.write (b,0,nRead); z8E1m"  
} ziiwxx_  
catch(Exception e){e.printStackTrace ();} "oR@JbdX  
} @ &pqt6/t  
} -U>y  
7/aOsW"6  
#Y2i*:<  
//打印回应的头信息 H]&gW/=  
public void logResponseHead(HttpURLConnection con) Or8kp/d  
{ E$A3|rjnoN  
for(int i=1;;i++) ~Wei|,w'<  
{ /`3#4=5-  
String header=con.getHeaderFieldKey(i); FQk!d$BG  
if(header!=null) ?{6s58Q{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :Wc_Utt  
Utility.log(header+" : "+con.getHeaderField(header)); H}/05e  
else Wpr ,jN8b  
break; MLr-, "gs  
} ,$N#Us(Wa  
} `XJm=/f  
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public void splitterStop() 2%]Z Kd  
{ vcv CD7MD  
bStop = true; BhkoSkr  
} [ *>AN7W  

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} d|lpec  
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/* A%XX5*  
**FileAccess.java cj$d=k~  
*//文件访问(定位，写) F9a
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package NetFox; r^1+cwy/7P  
import java.io.*; 02=lsV!U  
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> 'i  
public class FileAccessI implements Serializable{ 3I $>uR  
Z"y=sDO{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YlF%UPp  
RandomAccessFile oSavedFile; h&;t.Gdf  
long nPos; [9o4hw  
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public FileAccessI() throws IOException Kr-G{b_Pp  
{ WQ6"0*er  
this("",0); ba@ctkCW  
} %IY``r)j  
{A:j[  
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public FileAccessI(String sName,long nPos) throws IOException -LW[7s$  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); Ii&7rdoxe  
this.nPos = nPos; t:)ERT")  
oSavedFile.seek(nPos); e<cM[6H'D  
} !.TLW  
:O= \<t  
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public synchronized int write(byte[] b,int nStart,int nLen) 2%u;$pj  
{ V[nQQxWp=  
int n = -1; T~4N+fK  
try{ Qk1xUE  
oSavedFile.write(b,nStart,nLen); hA1-){aw3q  
n = nLen; .(CP. d  
} 8|%^3O 0X  
catch(IOException e) ~j9O$s~)  
{ 4\M.6])_  
e.printStackTrace (); EYX$pz(x;  
} $O)3q $|  
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return n; alq%H}FF  
} vVl; |  
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} BV#78,8(  
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/* TuDE@ gq(  
**SiteInfoBean.java D BE
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*/ Yz$3;  
package NetFox; $%R$G`.KM  
&<RpWAk{  
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public class SiteInfoBean { 26vp1  
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private String sSiteURL; //Site's URL :Bu2,EL*O  
private String sFilePath; //Saved File's Path L|@y&di  
private String sFileName; //Saved File's Name <FI-zca  
private int nSplitter; //Count of Splited Downloading File ma'FRt  
!V2/A1?  
sZGj"_-Hzu  
public SiteInfoBean() B=8Iu5m  
{//nSplitter的缺省值为5 GV
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//default value of nSplitter is 5 ^z6_Uw[  
this("","","",5); jh2t9SI~  
} #n0Y6Pr  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) uVyGk~  
{ y\
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sSiteURL= sURL; %\|'%/"`2(  
sFilePath = sPath; o6 E!IX+  
sFileName = sName;
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this.nSplitter = nSpiltter; lKZB?Kk^w\  
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} )WT>@  
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public String getSSiteURL() w}Uhd,  
{ o*U]v   
return sSiteURL; s*U1  
} $un?0S  
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public void setSSiteURL(String value) e@:sR  
{ iu&wO<)+?  
sSiteURL = value; AKMm&(fh%  
} ^P151*=D  
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public String getSFilePath() sVG(N.y  
{ ?T+q/lt4  
return sFilePath; mU}F!J#6  
} 4jD2FFG- G  
{43>m)8+  
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public void setSFilePath(String value) V3 ~~  
{ ]?*I9  
sFilePath = value; B,,D7cQC  
} P#=`2a#G  
RV@*c4KvO+  
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public String getSFileName() "*G.EiLq  
{ mZd , 9  
return sFileName; vWGwVH/K  
} r@ZJ{4\Q  
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public void setSFileName(String value) */|BpakD<  
{ tHzZ@72B7  
sFileName = value; pAT7)Ch  
} fbUr`~Y"  
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bV,}Pp+/"!  
public int getNSplitter() V+O"j^Z_J  
{ 9K1oZ?)_z  
return nSplitter; %2v4<icvq  
} yn#X;ja-  
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public void setNSplitter(int nCount) )ZN|t?|  
{ qvPtyc^fN  
nSplitter = nCount; Z?\>JM >;  
} B ~OZ2-~  
} 720DV+o  
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/* 8@tV9+u  
**Utility.java kh`"
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*/ 6i}iAP|0  
package NetFox; s_mS^`P7  
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h  
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public class Utility { :Y[LN  
z*-2.}&U<  
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public Utility() ?!+MM&c-n  
{ [UH||qW  
NX}<*
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wp&=$Aa)'  
} I1X-s  
EKO[!,  
//线程睡眠 AB4(+S*LA  
public static void sleep(int nSecond) UeRj< \"Q  
{ D|{jR~J)xK  
try{ HPZ}*m'  
Thread.sleep(nSecond); Ft
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} ')$+G152  
catch(Exception e) V;v8=1t!  
{ ml+; Rmvb  
e.printStackTrace (); % yw?s0  
}  a24"yT  
} o7$'cn  
!4X f~P  
//日志 I"ok&^t^}  
public static void log(String sMsg) f.9SB  
{ p9x(D/YP0  
System.err.println(sMsg); 1]p ZrBh"E  
} :>C2gS@  
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public static void log(int sMsg) H5Io{B%=
 
{ y2^Y/)   
System.err.println(sMsg); jWrj?DV,2N  
} qHrc9fB  
} +8R
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/* fSokm4]vg  
**TestMethod.java =Lf,?"S  
*/ XzE
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package NetFox; s*-n^o-  
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public class TestMethod { tg<EY!WY  
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public TestMethod() =ACVE;L?  
{ ///xx/weblogic60b2_win.exe 1ng!G 7g  
try{ ?j"KV_
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?B2] -+Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !1$])VQWI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6G[4rD&  
fileFetch.start(); ;)D];u|_  
} xHD=\,{ig  
catch(Exception e){e.printStackTrace ();} Utnr5^].2O  
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} YoBDvV":@  
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public static void main(String[] args) XovRg,  
{ YS/Yd[ e  
new TestMethod(); iOW#>66d  
} Ab{ K<:l  
} W04@!_) <  
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