http断点续传简单实现（java)

/* [FB&4>V/  
**SiteFileFetch.java 6/|U  
*/ c2/FHI0J;  
package NetFox; wOjv[@d  
import java.io.*; DWu
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import java.net.*; ?#4+r_dP  
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public class SiteFileFetch extends Thread { .SG0}8gW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 (%i!%{!]  
long[] nEndPos; //结束位置 l#Yx
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 7k>zuzRyF  
long nFileLength; //文件长度 Q5g,7ac8L  
boolean bFirst = true; //是否第一次取文件 K~USK?Q%  
boolean bStop = false; //停止标志 CP +4k.)*O  
File tmpFile; //文件下载的临时信息 Wt(Kd5k0'2  
DataOutputStream output; //输出到文件的输出流 _O$tuC%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o5>/}wIf  
public SiteFileFetch(SiteInfoBean bean) throws IOException /n(9&'H<  
{ -=}b;Kf-  
siteInfoBean = bean; vsH3{:&;"P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [4Y[?)7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :H{Bb{B%  
if(tmpFile.exists ()) i9KTX%s5^  
{ Ga.0Io&}C  
bFirst = false; <p09oZ{6  
read_nPos(); [qiOd!  
} INOH{`}Ew  
else M]1;  
{ GN0duV  
nStartPos = new long[bean.getNSplitter()]; ?C}sR:K/  
nEndPos = new long[bean.getNSplitter()]; ^ZR8s^X  
} `y'aH 'EEd  
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} AhR0zg  
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public void run() .`Sw,XL5  
{ V+46R ]  
//获得文件长度 gd K*"U  
//分割文件 F,zG;_  
//实例FileSplitterFetch p(.N(c  
//启动FileSplitterFetch线程 ^eobp.U  
//等待子线程返回 C*a,<`
  
try{ ;t|,nz4kJ  
if(bFirst) ?;_H{/)m  
{ <z',]hy  
nFileLength = getFileSize(); cg{Gc]'1#  
if(nFileLength == -1) @/LiR>,  
{ I :@|^PYw  
System.err.println("File Length is not known!"); "(<%Ua  
} bTiBmS  
else if(nFileLength == -2) >{b3>s~T  
{ };^}2Xo+  
System.err.println("File is not access!"); nW11wtiO.  
} g**5z'7  
else 3
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{ vnL?O8`c  
for(int i=0;i<nStartPos.length;i++) JxHv<p[  
{ ).Q[!lly  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); T
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} [T-*/}4$  
for(int i=0;i<nEndPos.length-1;i++) w]}f6VlEl  
{ ^(DL+r,  
nEndPos = nStartPos[i+1]; J B(<.E2  
} k&!6fZ)  
nEndPos[nEndPos.length-1] = nFileLength; $,@JYLC2  
} y`6
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} oJh"@6u6K  
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//启动子线程 c`ftd>]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Sj@15 W  
for(int i=0;i<nStartPos.length;i++) jccOsG9;_  
{ %7 /,m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :WO{xg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W/=7jM   
nStartPos,nEndPos,i); <cj}:H *  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _CL
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fileSplitterFetch.start(); m d_g}N(C  
} R B%:h-t4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pjdo|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =-5[Hn%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @i{]4rk lv  
nEndPos = " + nFileLength); i&*<lff  
// fileSplitterFetch[nPos.length-1].start(); (7~%B"  
cf\&No?-p  
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//等待子线程结束 "|hlDe<  
//int count = 0; 8+ hhdy*b  
//是否结束while循环 ` .$&T7  
boolean breakWhile = false; ` jyKCm.$#  
&//2eL  
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while(!bStop) >8(jW  
{ ($'V&x8T  
write_nPos(); F<gMUDB  
Utility.sleep(500); J)Ol"LXV  
breakWhile = true; hJLT!33:  
{!r#f(?uT  
_ ~[M+IO   
for(int i=0;i<nStartPos.length;i++) 1
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{ %4/xH9  
if(!fileSplitterFetch.bDownOver) JRo;(wqZ  
{ Bq;1^gtpe  
breakWhile = false; &r:=KT3  
break; Sz)b7:  
} >:$"a  
} x;(g  
if(breakWhile) GMw)*  
break; *Dc@CmBr  
&oEyixe  
fbV@=(y?  
//count++;
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//if(count>4) @k9Pz<ub  
// siteStop(); 7f r>ZY^  
} 0MrN:M2B  
^vM_kArA  
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System.err.println("文件下载结束！"); `O n(v  
} x0ne8NDP  
catch(Exception e){e.printStackTrace ();} Why"G
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} f"P$f8$  
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@ZG>mP1Vo  
//获得文件长度 x,uBJ  
public long getFileSize() t\%%d)d9  
{ *:
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int nFileLength = -1; `2e_ L  
try{ m9!DOL1pl  
URL url = new URL(siteInfoBean.getSSiteURL()); _r5wF(Y?7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7>mhK7l  
httpConnection.setRequestProperty("User-Agent","NetFox"); Wc\+x1:8  
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int responseCode=httpConnection.getResponseCode(); ?;RD u[eD  
if(responseCode>=400) ^RDU p5,T  
{ _D JCsK|  
processErrorCode(responseCode); E-F5y  
return -2; //-2 represent access is error WUY,. 8  
} RY<%'\A`~  
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String sHeader; ( OXY^iq  
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for(int i=1;;i++) 6klD22b2$  
{ xW0Z'==  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F|*tNJU>  
//Utility.log(in.readLine()); +ouY  
sHeader=httpConnection.getHeaderFieldKey(i); q)k{W>O  
if(sHeader!=null) OfJd/D  
{ Y;g% e3nu  
if(sHeader.equals("Content-Length")) v#F-<?Vv  
{ &
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [S)G$JW  
break;
}<&d]N  
} BfVBywty  
} O]bKNA.5  
else BUDGyl/=  
break; X|Dpt2A=  
} M}KZG'7  
} ?S9Nm~vlt  
catch(IOException e){e.printStackTrace ();} 5W{hH\E _5  
catch(Exception e){e.printStackTrace ();} W0|_]"K-  
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Utility.log(nFileLength); gb(#DbI  
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return nFileLength; _Fxe|"<^  
} 03F3q4"  
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//保存下载信息（文件指针位置） 0$QIfT)  
private void write_nPos() Uuz?8/w}#  
{ ? oc+ 1e  
try{ -f 4>MG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 82s5VQ6  
output.writeInt(nStartPos.length); pl?kS8#U?  
for(int i=0;i<nStartPos.length;i++) k,lqT>C  
{ -$9~xX  
// output.writeLong(nPos); yfC2^#9 Zu  
output.writeLong(fileSplitterFetch.nStartPos); rmQ\RP W  
output.writeLong(fileSplitterFetch.nEndPos); RAwk7F3qn  
} nzWQQra|?  
output.close(); =Sa~\k+  
} | +fwvi&a  
catch(IOException e){e.printStackTrace ();} K-6p'|  
catch(Exception e){e.printStackTrace ();} +dM.-wW  
} )WmZP3$^TX  
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//读取保存的下载信息（文件指针位置） 3;A$
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private void read_nPos() |,{+;:  
{ [aHlu[,  
try{ F:_F
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &urb!tQ>&  
int nCount = input.readInt(); gW}}5Xq  
nStartPos = new long[nCount]; eVrNYa1>H  
nEndPos = new long[nCount]; A6Q c;v+  
for(int i=0;i<nStartPos.length;i++) JSRg?p\  
{ H>Ks6V)RL4  
nStartPos = input.readLong(); 80HEAv,O  
nEndPos = input.readLong(); \6i9q=  
} cCk1'D|X[e  
input.close(); p
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} r.?+gW!C  
catch(IOException e){e.printStackTrace ();} A]#_"fayo  
catch(Exception e){e.printStackTrace ();} W#VfX!~  
} XHZLWh"gS  
8;0^'Qr8  
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private void processErrorCode(int nErrorCode) F=:c5z  
{ `BpCRKTG  
System.err.println("Error Code : " + nErrorCode); RW)k_#%=  
} 1 0V+OIC  
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c[Yq5Bu{y  
//停止文件下载 B6uf;Yc  
public void siteStop() 9!c
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{ .jCk#@+  
bStop = true; e_^KI  
for(int i=0;i<nStartPos.length;i++) =@%MV(  
fileSplitterFetch.splitterStop(); =^by0E2  
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} r&=r/k2  
} <9T [yg  
//负责部分文件的抓取 ijg,'a~3E  
**FileSplitterFetch.java
$:P[v+Uy  
*/ x7Eeb!s0f,  
package NetFox; n
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import java.io.*; *x5o=)Y  
import java.net.*; 27$\sG|g  
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public class FileSplitterFetch extends Thread { '&+Z,  
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#i6[4X?  
String sURL; //File URL R+C+$?4NG  
long nStartPos; //File Snippet Start Position %uF:)  
long nEndPos; //File Snippet End Position ayHn_  
int nThreadID; //Thread's ID *SWv*sD  
boolean bDownOver = false; //Downing is over ;>sq_4_  
boolean bStop = false; //Stop identical eUYG96Jw  
FileAccessI fileAccessI = null; //File Access interface 4U:DJ_GN  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v#w4{.8)  
{  PVS\,  
this.sURL = sURL; g\E ._ab<  
this.nStartPos = nStart; f.sPE8#3=  
this.nEndPos = nEnd; 0GF%~6  
nThreadID = id; s8C:QC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !:&2+%  
} +W!'B
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public void run() `;R|V  
{ ;9 lqSv/6  
while(nStartPos < nEndPos && !bStop) &0?DL  
{ H;4oZ[g  
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}6F_2S3c  
try{ NWaI[P
 
URL url = new URL(sURL); ~y( ,EO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9(V=Ubj  
httpConnection.setRequestProperty("User-Agent","NetFox"); +*WUH513  
String sProperty = "bytes="+nStartPos+"-"; 6f<*1YR F  
httpConnection.setRequestProperty("RANGE",sProperty); 7m vSo350  
Utility.log(sProperty); \nn56o@eN  
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InputStream input = httpConnection.getInputStream(); N.ItyV  
//logResponseHead(httpConnection); EG8%~k+R  
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byte[] b = new byte[1024]; iG?w;  
int nRead; q_OY sg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2X qPZ]2g  
{ 17?NR\Q  
nStartPos += fileAccessI.write(b,0,nRead); 7]R6  
//if(nThreadID == 1) 1==P.d(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N4
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} ayB=|*Q"  
_:/Cl9~  
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Utility.log("Thread " + nThreadID + " is over!"); Y0R\u\b  
bDownOver = true; v)X[gt tf  
//nPos = fileAccessI.write (b,0,nRead); k 2 mkOb  
} '` BjRg57]  
catch(Exception e){e.printStackTrace ();} +Y_Q?/M@8  
} y$+!%y*  
} )m$1al  
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Off: ~  
//打印回应的头信息 E1mI Xd;.  
public void logResponseHead(HttpURLConnection con) BZnp #}f  
{ 8,Q.t7v  
for(int i=1;;i++) \rB/83[;u  
{ U)IsTk~}O  
String header=con.getHeaderFieldKey(i); 7zz(#  
if(header!=null) mH7CgI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (@N~ j&
  
Utility.log(header+" : "+con.getHeaderField(header)); f z/?=  
else
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break; g~i''lng  
} ?(|TP^  
} 9OO0Ht4j  
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public void splitterStop() =PeW$q+  
{ N7Z(lI|a;  
bStop = true; +qu@dU0\`|  
} x _YV{  
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} wd2P/y42;;  
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/* kOlI?wc  
**FileAccess.java P5ESrZ@f  
*//文件访问(定位，写) VygXhh^7\  
package NetFox; c DEe?WS  
import java.io.*; ~I8"l@H>  
q^T&A[hMPx  
3>:zo:;  
public class FileAccessI implements Serializable{ qx#ghcU  
80R=r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +lXdRc`6  
RandomAccessFile oSavedFile; qAuUe=w%p  
long nPos; s\3Z?zm8  
%
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public FileAccessI() throws IOException HCe-]nMd  
{ o+6^|RP  
this("",0); J T0,Z  
} !@]h@MC$7  
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*6\`A!C  
public FileAccessI(String sName,long nPos) throws IOException =":V WHf  
{ =."WvBKg  
oSavedFile = new RandomAccessFile(sName,"rw"); iu:p&h  
this.nPos = nPos; iA{chQBr  
oSavedFile.seek(nPos); aF4V|?+  
} [XY:MUe  
r)Mx.`d!  
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public synchronized int write(byte[] b,int nStart,int nLen) R;Ix<y{U  
{ Hhce:E@K  
int n = -1; b$$L]$q2  
try{ 6r-<XNv)0  
oSavedFile.write(b,nStart,nLen);  zxynEdO  
n = nLen; UU:QK{{E  
} 0I ND9h.%  
catch(IOException e) Z:o' +oh  
{ v'
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e.printStackTrace (); Kw5+4R(5  
} bju,p"J1-E  
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return n; kdueQ(\  
} s"^YW+HMb  
qT-nD}  
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} A5>gLhl7  
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/* Q/9vDv  
**SiteInfoBean.java R;,u >P "  
*/ \5L4*  
package NetFox; %;\2QI`R  
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public class SiteInfoBean { ^Ihdq89t  
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private String sSiteURL; //Site's URL OmUw.VH  
private String sFilePath; //Saved File's Path Zn=JmZ  
private String sFileName; //Saved File's Name `a1R "A  
private int nSplitter; //Count of Splited Downloading File pa> 2JF*  
#}]il0d  
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public SiteInfoBean() (k HQKQmq  
{//nSplitter的缺省值为5 YI(OrR;V  
//default value of nSplitter is 5 H fmMf^c  
this("","","",5); BrH`:Dw  
} }Us
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <?va) ou  
{ L5N{ie_  
sSiteURL= sURL; e^fKatI1  
sFilePath = sPath;
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sFileName = sName; v(nQd6;T  
this.nSplitter = nSpiltter; (R 2P<
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} 1Qe!  
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!{ )AV/\D  
public String getSSiteURL() k^%ec3l  
{ xTawG?"D  
return sSiteURL; >yHnz?bf@  
} !?-5hh1\  
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public void setSSiteURL(String value) S/:QVs  
{ e ~,'|~ C5  
sSiteURL = value;  eJ\j{-  
} BNm va  
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}
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public String getSFilePath() 9TN
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{ ML"P"&~u6  
return sFilePath; f?I *`~k  
} .t%Vx  
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public void setSFilePath(String value) =X'7V}Q}  
{ 4g^+y.,r_f  
sFilePath = value; rxk{Li<9  
} _!p$47  
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e;u
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public String getSFileName() 4W-+k  
{ 1E_Ui1[  
return sFileName; g~D6.OZU  
} Gv3Fg[MA@c  
/g7?,/vnZ  
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public void setSFileName(String value) (eE}W~Z  
{ ' 1]bjW*!  
sFileName = value; #]/T9:  
} Ca"+t lO  
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public int getNSplitter() * CGdfdxW  
{ &_hCs![  
return nSplitter; =9@yJ9c-  
} '*Mb .s"  
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public void setNSplitter(int nCount) MFsy`aiS  
{ A+E@OOw*~  
nSplitter = nCount;  Hu2g (!  
} U+M?<4J)"  
} trt\PP:H%  
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/* BtApl)q#  
**Utility.java ~,-O  
*/ -)+DVG.t  
package NetFox; s""8V_,;  
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public class Utility { m6<0 hP  
-s "$I:v  
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public Utility() VjMuU"++@  
{ 4ux5G`oL  
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} Mwk_SCy  
rL"k-5>fd  
//线程睡眠 8{t&8Ql n  
public static void sleep(int nSecond) 6^u(PzlA|~  
{ =@  
try{ (.+n1)L?  
Thread.sleep(nSecond); N\&;R$[9:  
} ,^C;1ph  
catch(Exception e) xhS/X3<th  
{ ENjD~S  
e.printStackTrace (); uelTsn  
} +N_%|!F-c  
} 'A2"&6m)28  
qEz'l'%(  
//日志 P9wDTZ :4  
public static void log(String sMsg) nQmYeM  
{ 83*k.]S`  
System.err.println(sMsg); ^uzVz1%mM  
} 1`\kXaG  
Mp=+*I[  
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public static void log(int sMsg) _3[BS9  
{ nJg2O@mRJ  
System.err.println(sMsg); rM |RGe  
} ^u,x~nPXg  
}  '|T=  
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0VPa;{i/  
/* zy;w07-)  
**TestMethod.java u;}B4Rx
  
*/ S}O\<6&  
package NetFox; u)pBFs<dn  
czRh.kz,  
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public class TestMethod { RfRaWbn  
&N;6G`3  
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public TestMethod() _"V0vV  
{ ///xx/weblogic60b2_win.exe lsi8?91  
try{ &0`7_g7G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,cEcMaJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gK#w$s50  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (5_(s`q.  
fileFetch.start(); UMaKvr-C&  
} KW<CU'  
catch(Exception e){e.printStackTrace ();} Um<vs
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} ` 454=3H  
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public static void main(String[] args) {%Sww:  
{ ?|dz"=y  
new TestMethod(); h6t>yC\  
} v2V1&-
  
} eGil`:JY"  
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