http断点续传简单实现（java)

/* @c&}\#;  
**SiteFileFetch.java l*^J}oY  
*/ D$C>ZF  
package NetFox; qYD$_a  
import java.io.*; ^0A}iJL  
import java.net.*; RT
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public class SiteFileFetch extends Thread { Dep.Qfv{-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean eVL#3|=  
long[] nStartPos; //开始位置 }DH3_M!  
long[] nEndPos; //结束位置 V_b"^911r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >*DR>U  
long nFileLength; //文件长度 y|r+<  
boolean bFirst = true; //是否第一次取文件 !*2cK>`  
boolean bStop = false; //停止标志 UQq,Xq  
File tmpFile; //文件下载的临时信息 #2*l"3.$.R  
DataOutputStream output; //输出到文件的输出流 MBy0Ky  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） W5C8$Bqm  
public SiteFileFetch(SiteInfoBean bean) throws IOException <sU?q<MC  
{ c6v@6jzx0Y  
siteInfoBean = bean; &(M][Uo{|'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -D=J/5L#5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GYvD*?uBc  
if(tmpFile.exists ()) R _#x  
{ =;9
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bFirst = false; MW^(  
read_nPos(); @Z0?1+k  
} Q7<%_a  
else ;E,^bt<U  
{ G$#Q:]N  
nStartPos = new long[bean.getNSplitter()]; 'G] P09`*)  
nEndPos = new long[bean.getNSplitter()]; NC]]`O2r@  
} 2o8:[3C5  
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} U;SReWqU  
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public void run() uD'yzR!]+  
{ w&c6iFMd0  
//获得文件长度 xIt'o(jQH  
//分割文件 Y-Iu&H+\  
//实例FileSplitterFetch !H)$_d \uj  
//启动FileSplitterFetch线程 |nOqy&B  
//等待子线程返回 &,v-AL$:Q  
try{ E6 g]EE  
if(bFirst) o!6~tO=%  
{ j-~x==c-;  
nFileLength = getFileSize(); %}.4c8  
if(nFileLength == -1) Iax-~{B3AY  
{ `'W/uCpl  
System.err.println("File Length is not known!"); [z:.52@!  
} HgGwV;W  
else if(nFileLength == -2) *lZ;kW(}p  
{ ^pB}eh.@U  
System.err.println("File is not access!"); fL xGaOT  
}
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else e0s*  
{ ! qVuhad.  
for(int i=0;i<nStartPos.length;i++) C8{bqmlm@  
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q!9
 
} Cs:?9G  
for(int i=0;i<nEndPos.length-1;i++) 8 x=J&d  
{ }Z="}Dg|T  
nEndPos = nStartPos[i+1]; <bSG|VqnH  
} )2z<5
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nEndPos[nEndPos.length-1] = nFileLength; $Cgl$A  
} wDQ@$T^vh  
} #}PQ !gZ  
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//启动子线程 k kZ2Jxvx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UWW^g@d4  
for(int i=0;i<nStartPos.length;i++) uBp,_V?  
{ y ;/T.W9!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .2Q4
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W)X" G3  
nStartPos,nEndPos,i); #!0=I s^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N>TmaUk  
fileSplitterFetch.start(); ]iU8n (5f  
} o*k.je1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }}
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |?cL>]t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =l)D$l  
nEndPos = " + nFileLength); 3# g"Z7/  
// fileSplitterFetch[nPos.length-1].start(); @:dn\{Zsea  
k!Ym<RD%N  
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//等待子线程结束 f]pHJVgFV  
//int count = 0; m&PB5s\=  
//是否结束while循环 {4n  
boolean breakWhile = false; 4,,
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while(!bStop) @Ojbu@A  
{ t!8(IR  
write_nPos(); +TZVx(Z&A  
Utility.sleep(500); Af"p:;^z  
breakWhile = true; v~*Co}0OB  
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for(int i=0;i<nStartPos.length;i++) a Xn:hn~O  
{ AqA.
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if(!fileSplitterFetch.bDownOver) pqCp>BO?O  
{ xA'RO-a}h  
breakWhile = false; :' =le*h  
break; ptc.JB6  
} } =
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} n#l~B
@  
if(breakWhile) Bq5-L}z  
break; /n2qW.qJ>  
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//count++; j%U'mGx  
//if(count>4) ynZp|'b?<  
// siteStop(); 1!%T<!A.  
} zv-9z  
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c W1`[b  
System.err.println("文件下载结束！"); j].=,M<dxE  
} S`Xx('!/|  
catch(Exception e){e.printStackTrace ();} }Ug O$
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} Q\nIU7:bZ  
@CtnV|  
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//获得文件长度 1`sTGNo  
public long getFileSize() ,bxGd!&{Q  
{ 4Uk\hgT0  
int nFileLength = -1; z j F'CY  
try{ ZBkbr  
URL url = new URL(siteInfoBean.getSSiteURL()); XxYwBc'pc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hAV@/oQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); 
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o zMn8@R  
int responseCode=httpConnection.getResponseCode(); fB)S:f|  
if(responseCode>=400) 7Y%Si5  
{ K0{ ,*>C  
processErrorCode(responseCode); to{7B7t>q  
return -2; //-2 represent access is error >g;995tG  
} +MtxS l  
7<*,O&![|  
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String sHeader; S-[S?&c`  
lt("yqBu
 
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for(int i=1;;i++) kxLWk%V  
{ `qV*R 2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FN<Sagj  
//Utility.log(in.readLine()); l`A
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sHeader=httpConnection.getHeaderFieldKey(i); 8Sk$o.Gy  
if(sHeader!=null) 8
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{ Zg4kO;r08  
if(sHeader.equals("Content-Length")) $!vK#8-&{  
{ z?Cez*.h>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [VE>{4]W  
break; T<%%f.x[s  
}
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} aM4-quaG]  
else 4 'DEdx,&f  
break; gle<{ `  
} 48,uO!  
} -cWGF  
catch(IOException e){e.printStackTrace ();} !A:d9 k  
catch(Exception e){e.printStackTrace ();} d f j;e%H  
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n= q7*<l  
Utility.log(nFileLength); d/[kky}  
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return nFileLength; z~th{4#E;  
} e!ql8wbp  
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v"l8[::  
//保存下载信息（文件指针位置） &bigLe  
private void write_nPos() r3+   
{ K8W99:v  
try{ LMNmG]#!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PVSz%"
 
output.writeInt(nStartPos.length); t[ZGY,8  
for(int i=0;i<nStartPos.length;i++) y"|gC!V}  
{ C[,&Y&`j  
// output.writeLong(nPos); K@vU_x0Sl  
output.writeLong(fileSplitterFetch.nStartPos); UZ1Au;(|  
output.writeLong(fileSplitterFetch.nEndPos); -' =?Hs.  
} _`.Q7  
output.close(); !tSh9L;<O  
} d+nxvh?I8  
catch(IOException e){e.printStackTrace ();} c=D~hzN  
catch(Exception e){e.printStackTrace ();}  L
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} oS~;>]W  
+
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//读取保存的下载信息（文件指针位置） q<K/q"0-l  
private void read_nPos() NFPWh3),f  
{ lMgPwvs'  
try{ v\+`n^
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r)Ja\;  
int nCount = input.readInt(); Y(Y#H$w  
nStartPos = new long[nCount]; ]QQeUxi  
nEndPos = new long[nCount]; FzAzAl5  
for(int i=0;i<nStartPos.length;i++) q7p
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{ M[C)b\  
nStartPos = input.readLong(); <b?$-Rx  
nEndPos = input.readLong(); x->+wJm@s  
} }tQ^ch;Q  
input.close(); _:%i6c*"  
} ]
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catch(IOException e){e.printStackTrace ();} C%|m[,Gx  
catch(Exception e){e.printStackTrace ();} }lP`3e  
} BZ(DP_}&D  
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private void processErrorCode(int nErrorCode) X%T%N;P  
{ W^pf 1I8[  
System.err.println("Error Code : " + nErrorCode); n7|,b- <  
} VI-6t"l  
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6#Rco%07zI  
//停止文件下载 RIDl4c [  
public void siteStop() ZFX6iAxd  
{ e>P>DmlW  
bStop = true; *-S?bv,T'  
for(int i=0;i<nStartPos.length;i++) W![~"7?  
fileSplitterFetch.splitterStop(); mNsd&Rk'  
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[  
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} jSRi
 
} UX<)hvKj  
//负责部分文件的抓取 & JJ*?Dl  
**FileSplitterFetch.java _ n1:v~  
*/ shP}T[<  
package NetFox; z.?slYe[  
#0\* 86  
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import java.io.*; euW   
import java.net.*; ;t,v/
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public class FileSplitterFetch extends Thread { ^4'!B +}F  
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String sURL; //File URL 7,8TMd1`M  
long nStartPos; //File Snippet Start Position 8?x:PkK  
long nEndPos; //File Snippet End Position pYu6[  
int nThreadID; //Thread's ID tmM; Z(9t  
boolean bDownOver = false; //Downing is over Y>ATL  
boolean bStop = false; //Stop identical ):}A Quy]  
FileAccessI fileAccessI = null; //File Access interface !_;J@B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m~fDDQs  
{ 45$aq~%as  
this.sURL = sURL; q)KOI`A  
this.nStartPos = nStart; rk@qcQR  
this.nEndPos = nEnd; 8xG"hJR  
nThreadID = id; [Fv,`*/sm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8.7q -<Q  
} !^v~hD$_q  
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public void run() C5$?Y8B3  
{ vy2"B ch  
while(nStartPos < nEndPos && !bStop) fakad#O  
{ t5u#[*  
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}  
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try{ Q<ia  
URL url = new URL(sURL); E*fa&G~s )  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kp1 F"!  
httpConnection.setRequestProperty("User-Agent","NetFox"); C*B5"s"  
String sProperty = "bytes="+nStartPos+"-"; *K@O3n   
httpConnection.setRequestProperty("RANGE",sProperty); 1oQbV`P  
Utility.log(sProperty); {6wXDZxv  
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InputStream input = httpConnection.getInputStream(); 0>]&9'cn  
//logResponseHead(httpConnection); u47`&\  
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byte[] b = new byte[1024]; C>mFyl
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int nRead; LnN:;h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B., BP  
{ 3Co1bY:  
nStartPos += fileAccessI.write(b,0,nRead); s0/m qZ]s  
//if(nThreadID == 1) 2tCw{Om*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C8)Paop$  
} Aayd3Ph0%  
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Utility.log("Thread " + nThreadID + " is over!"); o@]n<ZYo  
bDownOver = true; 3d7A/7S  
//nPos = fileAccessI.write (b,0,nRead); TXS`ey  
}
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catch(Exception e){e.printStackTrace ();} PMW@xk^<Y  
} JO&RuAq  
} w'VuC82SZ  
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1  
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//打印回应的头信息 v0tFU!Q%  
public void logResponseHead(HttpURLConnection con) O, :|  
{ 4mEJu  
for(int i=1;;i++) Gm=&[?}  
{ TcJJ"[0  
String header=con.getHeaderFieldKey(i); Qz%q#4Zb  
if(header!=null) burSb:JF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kM=&Tfpj  
Utility.log(header+" : "+con.getHeaderField(header)); R!W
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else AN[pjC<  
break; pS7y3(_  
} rg]b$tL~  
} @\xEK5SG  
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public void splitterStop() qe(C>qjMbG  
{ :,
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bStop = true; fQg^^ZXe"  
} SMRCG"3qwA  
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} U2vb&Qu/  
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/* T g3MPa#g  
**FileAccess.java $AMcU5^b7  
*//文件访问(定位，写) M(C}2.20  
package NetFox; },Grg~l  
import java.io.*; G{Ju2HY  
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public class FileAccessI implements Serializable{ _4#7 ?p  
9Av{>W?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u(?U[pe[  
RandomAccessFile oSavedFile; bJR\d0Z  
long nPos; GkU$Z @  
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public FileAccessI() throws IOException ^nOh8L;  
{ H_Sv,lwz;c  
this("",0); D+jvF  
} :P+7ti@  
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public FileAccessI(String sName,long nPos) throws IOException ?A r}QN  
{ T('rM:)/  
oSavedFile = new RandomAccessFile(sName,"rw"); lb=fS%  
this.nPos = nPos; ,pf\g[tz  
oSavedFile.seek(nPos); ?@`5^7*  
}
$*P+  
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public synchronized int write(byte[] b,int nStart,int nLen) ]6|?H6'/`v  
{ "SWL@}8vx  
int n = -1; E piF$n  
try{ 'xaEG,P  
oSavedFile.write(b,nStart,nLen); !,5qAGi0  
n = nLen; DZb0'+jQ  
} aM,g@'.=  
catch(IOException e) T%Zfo7  
{ 6Rq +=X  
e.printStackTrace (); e},:QL0X  
} mRGr+m  
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return n; ]rg-=Y k  
} ymqn1ja1  
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!/|B4Yv  
} Ag2Q!cq  
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/* BrzTOkeyG  
**SiteInfoBean.java j/E(*Hv  
*/ J\'f5)k  
package NetFox; bS55/M w  
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public class SiteInfoBean { ^r7KEeVD  
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private String sSiteURL; //Site's URL 9]tW;?  
private String sFilePath; //Saved File's Path 9fM=5  
private String sFileName; //Saved File's Name ["ocZ? x  
private int nSplitter; //Count of Splited Downloading File `(O#$n  
$,I@c"m{  
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public SiteInfoBean() ;4v`FC>  
{//nSplitter的缺省值为5 ,,)'YhG(  
//default value of nSplitter is 5 $!z.[GL  
this("","","",5); P(C5@x(Z  
} A4;~+L:M  
)2Y]A^Y   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w^3S6lK  
{ < mFUT  
sSiteURL= sURL; wp4  .~E  
sFilePath = sPath; "tpD ->  
sFileName = sName; "l#"c{ee{  
this.nSplitter = nSpiltter; ^hT2ed +  
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} MBQ|*}+;  
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public String getSSiteURL() (g
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{ {\LLiU}MJC  
return sSiteURL; ?\X9Ei  
} mU||(;I  
f&] !;)  
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public void setSSiteURL(String value) B LZ<"npn  
{ _Vc4F_  
sSiteURL = value; g(Oor6Pp  
} ;MlPP)*k  
b!"FM/%  
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public String getSFilePath() k@[[vj|W  
{ p2+K-/}ApP  
return sFilePath; k%s,(2)30  
} CWd &  
Z 6][9o  
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public void setSFilePath(String value) 'S#^70kt  
{ 2) 2:KX  
sFilePath = value; c<Q*g  
} 7c@5tCcC-  
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public String getSFileName() eOZ~p  
{ C}9|e?R[Rz  
return sFileName; {q;_Dd  
} ,hT**(W  
;2sP3!*  
{q~N$"#  
public void setSFileName(String value) tejpY
 
{ F hyY+{%  
sFileName = value; Zu2 $$_+L  
} *Rc?rMF!  
,bB}lU)  
'#QZhz(+  
public int getNSplitter() !y2yS/  
{ fM*aZc*Y  
return nSplitter; eqWs(`  
} TA#pA(k  
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8'v:26   
public void setNSplitter(int nCount) s)sT\crP@  
{ [DtMT6F3  
nSplitter = nCount; oj,;9{-  
} z 5~X3k7  
} vrvi] Y8  
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kpQN>XV#  
/* dXU6TCjU7  
**Utility.java ?]TtUoY=)F  
*/ r -uu`=,  
package NetFox; D<*)^^  
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public class Utility { {D[z>I;D  
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public Utility() Gxt6]+r  
{ 7s
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} [Qqss8a  
W&&C[@Jd3  
//线程睡眠 KHeeB`V>J  
public static void sleep(int nSecond) 7!6v4ZA  
{ y+Bxe)6^V  
try{ )cm^;(#pV  
Thread.sleep(nSecond); )R"UX:Q>  
} =:H EF;!  
catch(Exception e) `2q]ju  
{ &m TYMpA  
e.printStackTrace (); $]^Io)}f@  
} m\|E
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} aQj6XGu  
H*",'`|-  
//日志 l o- 42)  
public static void log(String sMsg) j& L@L.d  
{ ~O3VX75f  
System.err.println(sMsg); SkU9i
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} N#X* 0i"  
i> {0h3Y  
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public static void log(int sMsg) w+XwPpM0.n  
{ [o 6  
System.err.println(sMsg); J@ 8OU  
} g}*p(Tp9:  
} )k4&S{=  
~!/agLwY  
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/* Z07n>|WF-  
**TestMethod.java LvL2[xh%&  
*/ 7<X!
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package NetFox; lKS 2OOYC`  
:
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public class TestMethod { FbW$H]C$  
;i?R+T  
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public TestMethod() bj?=\u  
{ ///xx/weblogic60b2_win.exe <J.q[fd1*  
try{ (Hs,Tj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'GLpSWL+*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U8<C
4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s/P+?8'9  
fileFetch.start(); `9
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} H9WXp&  
catch(Exception e){e.printStackTrace ();} e&NJj:Ph*  
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} pK0@H"$8  
S&c5Q*->[  
-Q%Pg<Q-#  
public static void main(String[] args) ZCNO_g  
{ Na+h+wD.D  
new TestMethod(); !y$+RA7\  
} "2PT]!  
} hsYv=Tw3C  
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