http断点续传简单实现（java)

/* (
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**SiteFileFetch.java EnJAHgRV;e  
*/ jZcjiOX  
package NetFox; g_}r)CgG|  
import java.io.*; '
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import java.net.*; W :PGj0?  
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public class SiteFileFetch extends Thread { ,>n 4 `A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \.A~>=
:  
long[] nStartPos; //开始位置 MEbx{XC  
long[] nEndPos; //结束位置 ur
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FileSplitterFetch[] fileSplitterFetch; //子线程对象  yf!  
long nFileLength; //文件长度 @4m_\]Wy  
boolean bFirst = true; //是否第一次取文件 nJF"[w,
?  
boolean bStop = false; //停止标志 :2?J#/o  
File tmpFile; //文件下载的临时信息 inavi5.  
DataOutputStream output; //输出到文件的输出流 v6 DN:!&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） . \*Z:  
public SiteFileFetch(SiteInfoBean bean) throws IOException nJny9g  
{ FS r`Y  
siteInfoBean = bean; ^9o;=!D!9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K3&v6 #]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pr.Vfb  
if(tmpFile.exists ()) m,v"N%k,  
{ G6xdGUM  
bFirst = false; TSmuNCR  
read_nPos(); eP-q[U?$n  
} o(w1!spA  
else Y'-BKZv!  
{ 6TxZ^&=  
nStartPos = new long[bean.getNSplitter()]; Z mF}pa,gd  
nEndPos = new long[bean.getNSplitter()]; b7{)B?n  
} ="RDcf/  
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} oYnA 3  
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public void run() )+Wx!c,mb  
{ A?q[C4-BO,  
//获得文件长度 A0yRA+  
//分割文件 u#?K/sU  
//实例FileSplitterFetch vV-ATIf
^  
//启动FileSplitterFetch线程 3@?#4]D{'  
//等待子线程返回 Ob?>zsx  
try{ Y:]~~-f\~  
if(bFirst) I@a7AuOw  
{ E
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nFileLength = getFileSize(); q(e&{pbM)  
if(nFileLength == -1) ;Aiuy{<  
{ |x2>F   
System.err.println("File Length is not known!"); 0]{h,W3]@[  
} @"-<m|lM  
else if(nFileLength == -2) %xf6U>T  
{ ^<$dTr'  
System.err.println("File is not access!"); fQlR;4Q
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} iCao;Zb  
else zuWj@YG\.  
{ g4P059  
for(int i=0;i<nStartPos.length;i++) 7_d gQI3y  
{ 7NRq5d(lP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tS8*l2Y`   
} LCK  
for(int i=0;i<nEndPos.length-1;i++) 'O8"M  
{ xZjD(e'  
nEndPos = nStartPos[i+1]; |Rw0$he  
} fzRzkn:=  
nEndPos[nEndPos.length-1] = nFileLength; tQbDP!,A*=  
} (tP>z+  
} .GM&]Hb  
+?[TH?2c+  
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//启动子线程  $.(%7[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }]N7CWy  
for(int i=0;i<nStartPos.length;i++) 7qV_QZ!.  
{ bqN({p&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &4sUi K"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ej47'#EY  
nStartPos,nEndPos,i); AQU4~g mI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); li8l+5d q  
fileSplitterFetch.start(); c~b[_J)  
} .B{3=z^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,(}7 ST  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hAHl+q)w?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bKYLBu:  
nEndPos = " + nFileLength); uI@:\Rss  
// fileSplitterFetch[nPos.length-1].start(); FEw51a+V  
5Jd&3pO  

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//等待子线程结束 OljUK,I]  
//int count = 0; `+1+0
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//是否结束while循环 9 bYoWw  
boolean breakWhile = false; [Pi8gj*  
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while(!bStop) 4~hd{8  
{ ~;QO`I=0P  
write_nPos(); PQ<""_S||  
Utility.sleep(500); jn>3(GRGC$  
breakWhile = true; E< "aUnI  
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for(int i=0;i<nStartPos.length;i++) t8\F7F P  
{ +'2Mj|d@p  
if(!fileSplitterFetch.bDownOver) gpVZZ:~  
{ @zB{Ig  
breakWhile = false; *4Y1((1k
 
break; Dr$k6kZ}'U  
} uDay||7^g  
} t@QaxZIlt;  
if(breakWhile) ;RB]aw
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break; (Ybc~M)z  
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//count++; ZK1d3
 
//if(count>4) r@f8-!{s2h  
// siteStop(); 2aX|E4F  
} Jm0P~E[n  
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System.err.println("文件下载结束！"); L&MR%5  
} 6C4c
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catch(Exception e){e.printStackTrace ();} C$SuFL(pb  
} g2JNa?z  
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//获得文件长度 )~v`dwKj;  
public long getFileSize() ;"-(QE?Mv  
{ K>l$Y#x}k  
int nFileLength = -1; F?\XhoJ3G  
try{ H)}>&Z4  
URL url = new URL(siteInfoBean.getSSiteURL()); Ij` %'/J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rE;*MqYt&
 
httpConnection.setRequestProperty("User-Agent","NetFox"); yhJH3<  
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int responseCode=httpConnection.getResponseCode(); qc2j}D0  
if(responseCode>=400) q,F\8M\$  
{ vm"LPwSk>  
processErrorCode(responseCode); z6]dF"N  
return -2; //-2 represent access is error 9u^PM  
} C$(US8:{  
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String sHeader; R8I%Cyc  
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for(int i=1;;i++) :m]~o3KRy  
{ f6vhW66:?x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); njtz,qt_;G  
//Utility.log(in.readLine()); "XlNKBgM  
sHeader=httpConnection.getHeaderFieldKey(i); ukpbx;O:hc  
if(sHeader!=null) [Ul"I-K  
{ HC(Vu  
if(sHeader.equals("Content-Length")) C-E~z{  
{ )'+" y~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 83K)j"!<X  
break; OB`(,m#  
} b3F)$UQ  
} -0r0M)  
else v/*}M&vo  
break; h/5|3  
} ADK)p?  
} ^\ A[^' 9  
catch(IOException e){e.printStackTrace ();} 4&X D  
catch(Exception e){e.printStackTrace ();} cWjb149@)  
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Utility.log(nFileLength); n75)%-  
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return nFileLength; FlGU1%]m  
} pqe7a3jr  
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//保存下载信息（文件指针位置） J{;XNf =  
private void write_nPos() K
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{ .a2b&}/.d  
try{ E! d?@Xr@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yJQ>u  
output.writeInt(nStartPos.length); ?+av9;Kg  
for(int i=0;i<nStartPos.length;i++) X-LCIT|1  
{ Q2yD4>qy  
// output.writeLong(nPos); W
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output.writeLong(fileSplitterFetch.nStartPos); xfoQx_]$Im  
output.writeLong(fileSplitterFetch.nEndPos); W*S}^6ZT`  
} Ln:6@Ok)5%  
output.close(); TOapq9B]  
} p3r("\Za,  
catch(IOException e){e.printStackTrace ();} p0*qv"lA  
catch(Exception e){e.printStackTrace ();} b S-o86u  
} }
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//读取保存的下载信息（文件指针位置） =LXjq~p  
private void read_nPos() Gyx4}pV  
{
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try{ S[ch/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q^\m@7O :  
int nCount = input.readInt(); &~mJ ).*  
nStartPos = new long[nCount]; &Va="HNKt  
nEndPos = new long[nCount]; b@QCdi,u  
for(int i=0;i<nStartPos.length;i++) Hg&.U;n  
{ IiU\}<O  
nStartPos = input.readLong(); %xt;&HE  
nEndPos = input.readLong(); %
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} [Ef6
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input.close(); 5(zdM)Y7  
} !3F3E8%  
catch(IOException e){e.printStackTrace ();} .;rE4B  
catch(Exception e){e.printStackTrace ();} vf&_ N  
} 5P Zzaz<  
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private void processErrorCode(int nErrorCode) M"Dv-#f  
{ c@3mfc
{  
System.err.println("Error Code : " + nErrorCode); xXf,j#`"  
} {Qi J-[q  
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//停止文件下载 AH{#RD  
public void siteStop() +0}z3T1L  
{ 6Hbu7r*tm  
bStop = true; t4iD<{4  
for(int i=0;i<nStartPos.length;i++) M>E~eb/  
fileSplitterFetch.splitterStop(); X+1Mv  
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} 3k3C\Cw  
} _9g-D9  
//负责部分文件的抓取 8.,d`~  
**FileSplitterFetch.java .TMLg(2hgv  
*/ V/3@iOwD  
package NetFox; [ *Dj7zt:  
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import java.io.*; N4#D&5I",  
import java.net.*; :YQI1 q[6  
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public class FileSplitterFetch extends Thread { `OfD^Q=  
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String sURL; //File URL uu9IUqEq2  
long nStartPos; //File Snippet Start Position O\CnKNk,  
long nEndPos; //File Snippet End Position ta6>St7.  
int nThreadID; //Thread's ID lb$_$+@Vr  
boolean bDownOver = false; //Downing is over [YP{%1*RM  
boolean bStop = false; //Stop identical CT5s`v!s  
FileAccessI fileAccessI = null; //File Access interface CY*o"@-o5)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m.p$f$A_  
{ #}Yrxf  
this.sURL = sURL; P1AC2<H  
this.nStartPos = nStart; c<,LE@V  
this.nEndPos = nEnd; wZZ~!"
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nThreadID = id; PtYG%/s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HMC-^4\%[  
} ,jEc4ih4  
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public void run() y=c={Qz@vn  
{ 7nNNc[d*=  
while(nStartPos < nEndPos && !bStop) 67hfve  
{ 7*j!ZUzp  
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try{ =6qTz3t  
URL url = new URL(sURL); #M{qMJHDo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q8&l%-d`  
httpConnection.setRequestProperty("User-Agent","NetFox"); i(pHJP:a:  
String sProperty = "bytes="+nStartPos+"-"; h}!9?:E  
httpConnection.setRequestProperty("RANGE",sProperty); E_En"r)y  
Utility.log(sProperty); ff5 gE'  
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InputStream input = httpConnection.getInputStream(); PcEE`.  
//logResponseHead(httpConnection); Db<#gH  

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byte[] b = new byte[1024]; /W)A[jR  
int nRead; j{YYG|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w8>h6x"  
{ g\fj6  
nStartPos += fileAccessI.write(b,0,nRead); GyWa=KW.u  
//if(nThreadID == 1) =$Mf:F@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); njf\fw_  
} *Q^z4UY  
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Utility.log("Thread " + nThreadID + " is over!"); V0v,s^\H  
bDownOver = true; >iae2W`
 
//nPos = fileAccessI.write (b,0,nRead); Fu_I0z  
} eFG(2OVg}M  
catch(Exception e){e.printStackTrace ();} sa4w.9O1GS  
} \$ipnQv  
} HB8s[]A:D  
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//打印回应的头信息 m<hP"j  
public void logResponseHead(HttpURLConnection con) GM0
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{ !*}UP|8  
for(int i=1;;i++) RC/ 3\'  
{ Q}|K29Y:p  
String header=con.getHeaderFieldKey(i); Bj1%}B  
if(header!=null) 8{!d'Pks
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >< $LV&  
Utility.log(header+" : "+con.getHeaderField(header)); d]
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else ]~I+d/k d  
break; bsF_.S*k@  
} 9Q%lS  
} 6sSwSS
 
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public void splitterStop() \4q|Qno8  
{ B={_}
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bStop = true; [|OII!"  
} b$7]cE  
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} PlGif)  
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/*  f\<r1  
**FileAccess.java 'd+fGx7i  
*//文件访问(定位，写) ki9&AFs2X  
package NetFox; qT@h/Y  
import java.io.*; v 49o$s4J  
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public class FileAccessI implements Serializable{ ?eIb7O  
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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 AU$~Ap*rsa  
RandomAccessFile oSavedFile; Dcvul4Q  
long nPos; 1.cP3kl  
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public FileAccessI() throws IOException Y[6T7eZ0g  
{ [Cl0Kw.LD  
this("",0); XP@dg4Z=z  
} R&Y_  
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public FileAccessI(String sName,long nPos) throws IOException i)o;,~ee  
{ ?bB>}:~j)  
oSavedFile = new RandomAccessFile(sName,"rw"); :5NMgR.d  
this.nPos = nPos; v|%41xOsr  
oSavedFile.seek(nPos); r%PWv0z_c  
} 7Jf~Bn  
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public synchronized int write(byte[] b,int nStart,int nLen) :<qe2Z5k  
{ r<UVO$N  
int n = -1; qT$k%(  
try{ egaX[j r  
oSavedFile.write(b,nStart,nLen); #d-({blo<  
n = nLen; NKO"'
   
}
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catch(IOException e) fu"cX;  
{ ,9P-<P  
e.printStackTrace (); 1B~O!']N<  
} /f3/}x!po  
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return n; (;l
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} E3uu vQ#|  
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} <Ua~+U(FR0  
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/* 6@N,'a8r  
**SiteInfoBean.java Y Zj-%5  
*/ X0
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package NetFox; T
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public class SiteInfoBean { aCG rS{  
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private String sSiteURL; //Site's URL @Q
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private String sFilePath; //Saved File's Path J>Ar(p  
private String sFileName; //Saved File's Name +A3/^C0  
private int nSplitter; //Count of Splited Downloading File f
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public SiteInfoBean() 46C%at M0}  
{//nSplitter的缺省值为5 ReaZg ?:h  
//default value of nSplitter is 5 E|@C:ghG  
this("","","",5); ?qjdmB|w  
} )d3 09O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'LYDJ~  
{ J n.7W5v  
sSiteURL= sURL; uN%C
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sFilePath = sPath; 4$Ai!a  
sFileName = sName; `cGks  
this.nSplitter = nSpiltter; F
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} )PN8HJAArh  
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public String getSSiteURL() 5U
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{ db )2>  
return sSiteURL; ZX_QnSNZ?  
} mIlg=8:  
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public void setSSiteURL(String value) kepuh%KY[  
{ ().C
  
sSiteURL = value; #/qcp|m  
} iA[T'+.Y  
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public String getSFilePath() QytO0K5  
{ ?1\5X<|,  
return sFilePath; k5RzW4zq;  
} SzLlJUVX  
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public void setSFilePath(String value) "@x(2(Y&  
{ +wQ5m8E  
sFilePath = value; Ec7xwPk  
} A+/Lt>+AS  
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public String getSFileName() %`~4rf"7  
{ #A>*pF  
return sFileName; \KV.lG!  
} SlsNtaNt  
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%jAc8~vW?  
public void setSFileName(String value) U#f*  
{ '&CZ%&(Gw  
sFileName = value; 0hS&4nW  
} IR/S`HD_  
KE\>T:  
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public int getNSplitter() ~vF*&^4Vh  
{ O!Ue0\1Kj0  
return nSplitter; 2Wcu.  
} r,eH7&P9{  
q
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public void setNSplitter(int nCount) o9sQ!gptw  
{ GVT 6cR  
nSplitter = nCount; !MSa -  
} i%yKyfD  
} +HE,Q6-A  
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/* $I5|rB/4?  
**Utility.java &Hw:65O  
*/ ^aaj=p:cV  
package NetFox; 4H;g"nWqO  
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public class Utility { d^'_H>x  
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public Utility()
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{ <_/etw86Z  
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} I>MLI=[Kg  
r[E#JHw  
//线程睡眠 ^3HSw ?a"  
public static void sleep(int nSecond) '(lsJY[-x  
{ hbXmIst  
try{ ~U<j_j)z4.  
Thread.sleep(nSecond); s\'t=}0q  
} -/8V2dv3  
catch(Exception e) ;4+z~7Je]^  
{ \1R
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e.printStackTrace (); Xk:x=4u&  
} hj=n;,a9  
} covCa)kf  
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//日志 i(rYc  
public static void log(String sMsg) j\#)'>"  
{ C4E*q3[Y  
System.err.println(sMsg); D[T\_3W  
} L{sFR^-G  
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public static void log(int sMsg) i{g~u<DH)Q  
{ oKRI2ni$j9  
System.err.println(sMsg); k8Dk;N  
} } %3;j5 ;6  
} 9'X"a  
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=j_4!^  
/* !rx5i  
**TestMethod.java nJH'^rO!C  
*/ ;&b=>kPlZ  
package NetFox; m%U=:u7#M  
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public class TestMethod { k]4CN  
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p@$92> '  
public TestMethod() o/U}G,|G  
{ ///xx/weblogic60b2_win.exe ='#7yVVcs  
try{ \hJLa  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); be6`Sv"H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~HctXe'x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8pmWw?  
fileFetch.start(); 7x*L 1>[`'  
} 98}l`J=i  
catch(Exception e){e.printStackTrace ();} ~LH).\V  
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} } BP.t$_  
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public static void main(String[] args) H2_6m5[&,  
{ j"0TAYmXwu  
new TestMethod(); TIV|7nKL  
} N,)rrBD  
} F0xm%?  
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