http断点续传简单实现（java)

/* M SnRx*-  
**SiteFileFetch.java WXj iKW(  
*/ z{q
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package NetFox; >x3$Ld  
import java.io.*; `xq/<U;i  
import java.net.*; Fs3rsig  
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public class SiteFileFetch extends Thread { '|7'dlW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Sc/\g  
long[] nStartPos; //开始位置 D^30R*gV  
long[] nEndPos; //结束位置 O u-/dE%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yU{Q`6u T  
long nFileLength; //文件长度 J
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boolean bFirst = true; //是否第一次取文件 v]?zG&Jh  
boolean bStop = false; //停止标志 "G[yV>pxv  
File tmpFile; //文件下载的临时信息 %`# HGji)  
DataOutputStream output; //输出到文件的输出流 ]Uu:t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b)(rlX  
public SiteFileFetch(SiteInfoBean bean) throws IOException d$gT,+|vu  
{ $SbgdbX  
siteInfoBean = bean; nkxv,_)ZT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "8#EA<lsS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) |nMg.t`8  
{ yP^C)  
bFirst = false;  
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read_nPos(); O!U8"Yr$  
} `:Bm@eN  
else {2v,J]v_[  
{ SmUj8?6"  
nStartPos = new long[bean.getNSplitter()]; +I>V9%%vW_  
nEndPos = new long[bean.getNSplitter()]; $[xS>iuD  
} r1A<XP|1?I  
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} csd~)a nb  
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public void run()
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{ @r*
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//获得文件长度 8-u #<D.  
//分割文件 U(rY,4'  
//实例FileSplitterFetch UID0|+%Y  
//启动FileSplitterFetch线程 gtwUY
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//等待子线程返回 {y%cTuC=  
try{ b9Mp@I7Q-  
if(bFirst) r^v1_u,1I  
{ crbph.0  
nFileLength = getFileSize(); /=K(5Xd  
if(nFileLength == -1) X? l5}  
{ /_D_W,#P  
System.err.println("File Length is not known!"); %nV6#pr  
} 1$#
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else if(nFileLength == -2) 8n"L4jb(:  
{ O\+b1+&b3Y  
System.err.println("File is not access!"); 53<.Knw5a  
} p&$O}AX|  
else &~KAZ}xu  
{ Z4s+8cTHn  
for(int i=0;i<nStartPos.length;i++) WXs?2S*  
{ *w OU=1+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I R|[&}z  
} HPc~wX  
for(int i=0;i<nEndPos.length-1;i++) EpU}~vC9C  
{ )_a;xB`S(  
nEndPos = nStartPos[i+1]; WI6h G  
} X8\UTHT&0  
nEndPos[nEndPos.length-1] = nFileLength; { u %xc"0y  
} %}}?Y`/W)  
} 0$BX8?Z  
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//启动子线程 Pq(7lua7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3%(,f,  
for(int i=0;i<nStartPos.length;i++) ]R*h3U@5#K  
{ X#<+D
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !!+LFe4su  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;wa#m1  
nStartPos,nEndPos,i); &[7z:`+Y##  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AaLbJYuKd  
fileSplitterFetch.start(); r
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} 9U4 D$M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g%_3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MS`XhFPS.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0t(2^*I?>  
nEndPos = " + nFileLength); TXS{=  
// fileSplitterFetch[nPos.length-1].start(); ^jE8 "G*  
_A~>?gJ;,  
;Sl%I+?  
//等待子线程结束 KsSIX
  
//int count = 0; <)a7Nrc\T  
//是否结束while循环 SajasjE!^1  
boolean breakWhile = false; +n>
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while(!bStop) 8gxo{<,9  
{ |)y-EBZe\"  
write_nPos(); Y~k,AJ{ ^  
Utility.sleep(500); &)izh) FA  
breakWhile = true; hplxs#  
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for(int i=0;i<nStartPos.length;i++) +Kp8X53  
{ ()W`4p  
if(!fileSplitterFetch.bDownOver) sV;q(,oru  
{ GmH`ipi  
breakWhile = false; &f
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break; 3vHkhhYQ  
} }U
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} Ce/D[%  
if(breakWhile) /V }Z,'+  
break; [0!*<%BgK'  
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//count++; 3Mq%3jX  
//if(count>4) +45.fo  
// siteStop(); '?Xf(6o1  
} #x6EZnG  
#wZbG|%  
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System.err.println("文件下载结束！"); aZ8f>t1Q  
} Vy6~O|68=  
catch(Exception e){e.printStackTrace ();} ^"iJ  
} cs 58: G5  
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//获得文件长度 Md&K#)9,(  
public long getFileSize() Dxe]LES\]  
{ |$Cfm}  
int nFileLength = -1; \olY)b[  
try{ Z>[n~{-,p  
URL url = new URL(siteInfoBean.getSSiteURL()); p2 !w86 F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >*EJ6FPO  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ I J^
 
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int responseCode=httpConnection.getResponseCode(); JfRLq
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if(responseCode>=400) ?DE{4Ti/[  
{ Myf2"\}  
processErrorCode(responseCode); KB{IWu  
return -2; //-2 represent access is error Wf~PP;  
} :<v@xOzxx  
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String sHeader; 3G'cDemc  
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for(int i=1;;i++) +LlAGg]Z  
{ <Y"HCa{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U,8mYv2|  
//Utility.log(in.readLine()); BKV:U\QZ  
sHeader=httpConnection.getHeaderFieldKey(i); 6]mAtA`Y  
if(sHeader!=null) d4)0G-|  
{ yZ)-=H  
if(sHeader.equals("Content-Length")) p^w_-(p  
{ 2Vs+8/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o1k+dJUd  
break; .hjN*4RY  
} xwj{4fzpk{  
}  `)>}b 3  
else 0./Rdf=-1j  
break; iI;np+uYk  
} w,j;XPp  
} ,hZ?]P&  
catch(IOException e){e.printStackTrace ();} y(O~=S+<  
catch(Exception e){e.printStackTrace ();} ;M"[dy`dY  
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Utility.log(nFileLength); jhkXU+4  
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return nFileLength;  pLM?m  
} nd[Ja_h  
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//保存下载信息（文件指针位置） Y?-Ef sK  
private void write_nPos() {"*_++|  
{ >>cL"m  
try{ n]t3d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )$K\:w>  
output.writeInt(nStartPos.length); v3(0Mu0J  
for(int i=0;i<nStartPos.length;i++) 5=b6B=\*~  
{ fu?u~QZ8  
// output.writeLong(nPos); "bz.nE*  
output.writeLong(fileSplitterFetch.nStartPos); 03_M+lv  
output.writeLong(fileSplitterFetch.nEndPos); h gu\~}kD  
} wYDdy gS  
output.close(); Lt i2KY}/%  
} |{RCvm  
catch(IOException e){e.printStackTrace ();} 9v1Snr  
catch(Exception e){e.printStackTrace ();} {;Oj  
} ],{M``]q  
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//读取保存的下载信息（文件指针位置） s<oT,SPt  
private void read_nPos() P.jy7:dB,  
{ %/BBl$~ji  
try{ WO6+r?0M2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b;nqhO[f}  
int nCount = input.readInt(); o6:@j#b  
nStartPos = new long[nCount]; wr~Qy4 ny  
nEndPos = new long[nCount]; S]A[eUF~  
for(int i=0;i<nStartPos.length;i++) vQj{yJ\l1  
{ &*oljGt8  
nStartPos = input.readLong(); ?A04qk  
nEndPos = input.readLong(); qE8Di\?  
} h,6>^A  
input.close(); SwaMpNXL  
} orbz`IQc  
catch(IOException e){e.printStackTrace ();} JSx[V<7m  
catch(Exception e){e.printStackTrace ();} 7PwH&rI  
} shO4>Ha  
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private void processErrorCode(int nErrorCode) V;Q@'<w  
{ Wys$#pJ  
System.err.println("Error Code : " + nErrorCode); fAfB.|cd  
} rV2>;FG  
5kADvi.  
>U?#'e{qW  
//停止文件下载 !)}D_9{  
public void siteStop() 4G hg~0  
{ L">m2/ HG  
bStop = true; er2;1TW3E  
for(int i=0;i<nStartPos.length;i++) EfkBo5@Qi  
fileSplitterFetch.splitterStop(); M:L-j{?y_  
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# %'%LY=  
} )\kNufP  
} ~#)9Kl7<X  
//负责部分文件的抓取 Fq`@sM$  
**FileSplitterFetch.java %NfH`%`  
*/ 02)Ybp6y  
package NetFox; AP8J28I  
6j!a*u:}"  
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import java.io.*; 44KWS~  
import java.net.*; j&b<YPZ  
_Y$v=!fY&  
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public class FileSplitterFetch extends Thread { C4t~
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String sURL; //File URL [?(qhp!  
long nStartPos; //File Snippet Start Position #a'CoJs   
long nEndPos; //File Snippet End Position  v&7x ~!O  
int nThreadID; //Thread's ID \&U"7gSL  
boolean bDownOver = false; //Downing is over bjN"H`Q  
boolean bStop = false; //Stop identical vV*/"'>  
FileAccessI fileAccessI = null; //File Access interface Z=<D`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wo$ F_!3u  
{ ;&kZ
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this.sURL = sURL; Ik@MIxLK  
this.nStartPos = nStart; 1F+nWc2b  
this.nEndPos = nEnd; ju4wU;Nu  
nThreadID = id; {UF|-VaG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~q}]/0-m  
} pW>.3pj  
'*t<g@2$  
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public void run() 5d}bl{  
{ ,4}s 1J#  
while(nStartPos < nEndPos && !bStop) xsrdHP
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{ 2uMSeSx$  
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try{ A5O;C
 
URL url = new URL(sURL); jO`L:D/C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vkW;qt}yO  
httpConnection.setRequestProperty("User-Agent","NetFox"); a)6?:nY$  
String sProperty = "bytes="+nStartPos+"-"; }VVtv1  
httpConnection.setRequestProperty("RANGE",sProperty); gEq6[G  
Utility.log(sProperty); a t=;}}X  
$. sTb  
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InputStream input = httpConnection.getInputStream(); e'=#G$S?g  
//logResponseHead(httpConnection); `qZ@eGZ z  
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3ZvQUH/{W  
byte[] b = new byte[1024]; v{8r46Y~Z)  
int nRead; /)rv Ndn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9Z3Vf[n5\  
{ W=2]!%3#  
nStartPos += fileAccessI.write(b,0,nRead); ;)sC{ "Jb  
//if(nThreadID == 1) 5 L-6@@/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fv
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} L_!}R  
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Utility.log("Thread " + nThreadID + " is over!"); ytV4qU82G  
bDownOver = true; t3!~=U  
//nPos = fileAccessI.write (b,0,nRead); ~$7YEs)  
} 0f;|0siTAm  
catch(Exception e){e.printStackTrace ();} u0$}VO5/a  
} lvUWs  
} ESe$6)P  
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//打印回应的头信息 j"&Oa&SH  
public void logResponseHead(HttpURLConnection con) ,ZnL38GW  
{ lnV!Xuf  
for(int i=1;;i++) cQ0+kX<  
{ Tcq@Q$H  
String header=con.getHeaderFieldKey(i); PW9tZx#  
if(header!=null) lW]&a"1$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZZ>(o d!B  
Utility.log(header+" : "+con.getHeaderField(header)); u#3Cst8Y  
else vQ{mEaH  
break; $@[Mo   
} d2g7,axi  
} '/Xm%S  
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public void splitterStop() jW}hLjlN  
{ CR-2>,*a9  
bStop = true; F5
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} ^YEMR C  
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} Ul:M=8nE%  
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IN"6=2:  
/* dAjm4F-  
**FileAccess.java Q*/jQC  
*//文件访问(定位，写) 5"Y:^_8  
package NetFox; hP jL  
import java.io.*; ~e+pa|lO  
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) =|8%IrB  
public class FileAccessI implements Serializable{ =8DS~J{  
u/5)Yx+5_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DF"*[]^[  
RandomAccessFile oSavedFile; So#>x5dL  
long nPos; yuF\YOA9  
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public FileAccessI() throws IOException U2(mWQ[mO  
{ \%.&$z3wz  
this("",0); *(nu0  
} Bo/i =/7%  
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public FileAccessI(String sName,long nPos) throws IOException (z%OK[  
{ Qs_]U  
oSavedFile = new RandomAccessFile(sName,"rw"); |PLWF[+t8  
this.nPos = nPos; "T6s;'k  
oSavedFile.seek(nPos); p%e/>N.P  
} a,[NcdG  
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public synchronized int write(byte[] b,int nStart,int nLen) ymA8`k5>@  
{ `(@{t:L  
int n = -1; w#;y  
try{ SdJkno  
oSavedFile.write(b,nStart,nLen); RIF*9=,S  
n = nLen; L>,xG.oG  
} M =GF@C;b  
catch(IOException e) (}CA?/  
{ "D
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e.printStackTrace (); 05;J7T<  
} QH6_nZY  
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return n; E1|:t$>Ld  
} >):>Pz%U  
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} a.SxMF  
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/* wUmcA~3D  
**SiteInfoBean.java xc$jG?83#  
*/ wmit>69S  
package NetFox; m?`$NJST  
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public class SiteInfoBean { 6$p6dmV|  
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private String sSiteURL; //Site's URL :"Kr-Hm`  
private String sFilePath; //Saved File's Path 2;YL+v2  
private String sFileName; //Saved File's Name E)(Rhvij  
private int nSplitter; //Count of Splited Downloading File qLm g18  
wmFS+F4`2  
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public SiteInfoBean() @5TJ]=  
{//nSplitter的缺省值为5 2Xp?O+b#"O  
//default value of nSplitter is 5 A)D1 #,0  
this("","","",5); Us8nOr>5  
} ?) VBkA5j  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) AM4 :xz  
{ :Pi="  
sSiteURL= sURL; p}-B>v  
sFilePath = sPath; Q E*`#r#e  
sFileName = sName; i  M!=/  
this.nSplitter = nSpiltter; MH_3nN  
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} Z<$y)bf  
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public String getSSiteURL() jftf]n&Z(q  
{ u/X1v-2  
return sSiteURL; }e&Z"H |  
} .
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public void setSSiteURL(String value) Z=>#|pW,)  
{ z4*`K4W  
sSiteURL = value; k54Vh=p  
} 6?KJ"Ai9  
EnXTL]=0S  
X##hSGQM  
public String getSFilePath() BW&)Zz  
{ _.3O(?p,  
return sFilePath; #Ue_  
} ]jwF[D  
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public void setSFilePath(String value) kY`L[1G$  
{ _0qp!-l}  
sFilePath = value; Py-}tFr  
} _tpqo>  
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public String getSFileName() lAx^!#
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{ +(J{~A~  
return sFileName; ?ZT+4U00U  
} ($Ck5`_MK  
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public void setSFileName(String value) by0M(h  
{ $${9 %qPzb  
sFileName = value; =9#cf-?  
} R(N5K4J  
t5jZ8&M5]  
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public int getNSplitter() 84u%_4/  
{ R3gg{hQ  
return nSplitter; \v[?4[  
} YV
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public void setNSplitter(int nCount) AF-uTf  
{ fs wQ*  
nSplitter = nCount;  oN7JNMT  
} ;]xJC j  
} l<=Y.P_2  
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/* [DO U
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**Utility.java Uk|(VR9  
*/ nRlvW{p;  
package NetFox; zeG_H}[2&  
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public class Utility { i$!-mYi+Q!  
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public Utility() $d_%7xx  
{ E8s&.:;+  
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} U4ELlxGe  
eW^_YG%(  
//线程睡眠 MC&sM-/  
public static void sleep(int nSecond) ;OynkZs)  
{ Y]gb`z$?  
try{ sM$g
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Thread.sleep(nSecond); .,5N/p"aV  
} a+Z95~*sZ"  
catch(Exception e) W_ hckq.  
{ #^~[\8v>  
e.printStackTrace (); |T@\-8Ok  
} (:2,Rr1"  
} 1JXa/f+  
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//日志 ^q=D!g  
public static void log(String sMsg) _@Le MNv  
{ llP 5  
System.err.println(sMsg); JD}"_,-  
} t^zmvPDK  
">^O{X\  
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public static void log(int sMsg) B1!b@0^  
{ 9dFSppM  
System.err.println(sMsg); Z U^dLN-N  
} u!VAAX  
} Q-g}{mFS  
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) ]x/3J@  
/* 43 h0i-%1  
**TestMethod.java xVn"xk  
*/ ,AO]4Ec  
package NetFox; 42wa9UL<Ka  
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public class TestMethod { ZfYva(zP{Q  
)|?s!rw +  
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public TestMethod() ;P#c!  
{ ///xx/weblogic60b2_win.exe uYv"5U]MFv  
try{ l].Gz`L
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v9qgfdBS5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @GpM4>:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dE[nPtstb  
fileFetch.start(); &eHhj9  
} W%xg;uzp  
catch(Exception e){e.printStackTrace ();} MWxv\o   
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} "X }@VT=  
l"#}g%E  
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public static void main(String[] args) t<|S7EqIL  
{ &(]@L\A  
new TestMethod(); l12_&o"C~  
} 9$u'2TV  
} P~5[.6gW  
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