http断点续传简单实现（java)

/* 63A}TBC  
**SiteFileFetch.java iTaWup  
*/ /t(C>$ }p  
package NetFox; dUsxvho  
import java.io.*; --DoB=5%8  
import java.net.*; Sf8{h|71  
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public class SiteFileFetch extends Thread { rXHv`ky  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0x!2ihf  
long[] nStartPos; //开始位置 Fgh]KQ/5  
long[] nEndPos; //结束位置 QPq7R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b6*!ACY  
long nFileLength; //文件长度 ]~Z6;  
boolean bFirst = true; //是否第一次取文件 0#MqD[U(  
boolean bStop = false; //停止标志 h\'n**f_x  
File tmpFile; //文件下载的临时信息 %'T #
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DataOutputStream output; //输出到文件的输出流 N 8-oY$*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "]G\9b)  
public SiteFileFetch(SiteInfoBean bean) throws IOException AQ='|%  
{ 0P]E6hWgg  
siteInfoBean = bean; wm^J;<T[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >+[&3u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2;?I>~  
if(tmpFile.exists ()) )YqXRm  
{ FLY Ca  
bFirst = false; ,`aq+K  
read_nPos(); FKmFo^^0  
}
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else LlSZr)X  
{ `[n("7,  
nStartPos = new long[bean.getNSplitter()]; %$DI^yS  
nEndPos = new long[bean.getNSplitter()]; =yy5D$\  
} uyY|v$FM  
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} Cn[0(s6  
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public void run() jkvg
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{ tzh1s i  
//获得文件长度 2rZxSg  
//分割文件 ,tg0L$qC  
//实例FileSplitterFetch &ZQJ>#~j^  
//启动FileSplitterFetch线程 ~_!F0
1s  
//等待子线程返回
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try{ o-Ga3i 8  
if(bFirst) ZR'H\Z  
{ i _%Q`i  
nFileLength = getFileSize(); Kx%Sku<F'  
if(nFileLength == -1) 2j&AiD  
{ L~KM=[cn  
System.err.println("File Length is not known!"); dYgXtl=#j  
} fX|Y;S-@+  
else if(nFileLength == -2) >_LDMs[-p  
{ T'b_W,m~,u  
System.err.println("File is not access!"); =*LS%WI  
} %x} O1yV  
else $O5UyKI  
{ )<Hd T  
for(int i=0;i<nStartPos.length;i++) s S7c!  
{ J:\|Nc?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [r[=W!  
} 0xXC^jx:  
for(int i=0;i<nEndPos.length-1;i++) ;I!MLI  
{ jXMyPNTK  
nEndPos = nStartPos[i+1]; >MvDVPi~+  
} >HS W]"k  
nEndPos[nEndPos.length-1] = nFileLength; N~xLu8,  
} X'
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} L:'J Bhg  
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//启动子线程 oo.2Dn6z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }O4
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for(int i=0;i<nStartPos.length;i++) q')R4=0 K  
{ `kJ^zw+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `{xNXH]@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +o51x'Ld*  
nStartPos,nEndPos,i); O7$hYk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~7Tc$ "I  
fileSplitterFetch.start(); =pC3~-;3  
} c?,i3s+2Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e[#j.|m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v7`HQvQEz=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d
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nEndPos = " + nFileLength); ]]wA[c~G  
// fileSplitterFetch[nPos.length-1].start(); ^!by3Elqqk  
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//等待子线程结束 S9",d~EM  
//int count = 0; h^o{@/2  
//是否结束while循环 <z!CDg4  
boolean breakWhile = false; [n$BRk|  
6 M*O{f
 

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while(!bStop) &sL&\+=<(  
{ ?28N ^  
write_nPos(); M%0C_=zg  
Utility.sleep(500); JQ@E>o7_  
breakWhile = true; [YcG(^^  
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for(int i=0;i<nStartPos.length;i++) !f+H,]D"  
{ 9amaL~m  
if(!fileSplitterFetch.bDownOver) C-H@8p?T  
{ 5)MS~ii  
breakWhile = false; }dd8N5b  
break; dp*u9z~NA  
} F;<xnC{[  
} CLJ;<  
if(breakWhile) <>aw 1WM+  
break; <h'5cO  
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//count++; t>$kWd{9e;  
//if(count>4) >b{q.  
// siteStop(); %eO0wa$a  
} H"dJ6  
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System.err.println("文件下载结束！"); -#HA"7XOE  
} hs$GN
]  
catch(Exception e){e.printStackTrace ();} u!W0P6   
} M%kO7>h8  
Oz%>/zw[h
 
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//获得文件长度 LpqO{#ZG  
public long getFileSize() 6'Worj  
{ E}nH1  
int nFileLength = -1; pj?f?.^  
try{ 7w6cwHrL@  
URL url = new URL(siteInfoBean.getSSiteURL()); L>RP-x>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ls] g  
httpConnection.setRequestProperty("User-Agent","NetFox"); u2?|Ue@[  
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int responseCode=httpConnection.getResponseCode(); &H`jL4S  
if(responseCode>=400) MfWyc_  
{ (j3xAA  
processErrorCode(responseCode); YS*9t Q{  
return -2; //-2 represent access is error 65aK2MS@  
} !74S  
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String sHeader; ?3.b{Cq{-  
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for(int i=1;;i++) ?}U(3  
{ "\o+v|;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )j0TeE1R  
//Utility.log(in.readLine()); In<n&ib  
sHeader=httpConnection.getHeaderFieldKey(i); 7OJ'){R$  
if(sHeader!=null) n+A?"`6*#  
{ ikvWh<=>H  
if(sHeader.equals("Content-Length")) qtQ6cqLd  
{ u*ObwcI/Bn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ''\O
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break; Dw<bn<e-  
} SX# e:_  
} x?2@9u8Yb  
else O4V.11FnW  
break; KQg]0y d  
} 9|gr0&#~j  
} 2h1vVF3  
catch(IOException e){e.printStackTrace ();} O#S
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catch(Exception e){e.printStackTrace ();} Pn>Xbe  
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Utility.log(nFileLength);
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return nFileLength; )E-inHD /  
} 6&!PmKFO.  
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//保存下载信息（文件指针位置） F.=2u"[*&  
private void write_nPos() C8V/UbA /  
{ f-`)^5E  
try{ 6MT1$7|P&x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y+c|vdW%  
output.writeInt(nStartPos.length); {_ i\f ]L  
for(int i=0;i<nStartPos.length;i++) Kk-S}.E  
{ G <i@ 5\#  
// output.writeLong(nPos); K,:cJ  
output.writeLong(fileSplitterFetch.nStartPos); ECrex>zr%  
output.writeLong(fileSplitterFetch.nEndPos); uP~@U"!  
} eOs)_?}  
output.close(); H?&
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} $+Z)  
catch(IOException e){e.printStackTrace ();} "2)H'<  
catch(Exception e){e.printStackTrace ();} ]dGw2y  
} .ZVUd84B  
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//读取保存的下载信息（文件指针位置） 06c>$1-?  
private void read_nPos() OHb[qX\  
{ 3W3ZjdV+  
try{ ?"i}^B`*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j/_s"}m{  
int nCount = input.readInt(); LHkc7X$  
nStartPos = new long[nCount]; jU9$Ehg I  
nEndPos = new long[nCount]; 34%RZG_o'  
for(int i=0;i<nStartPos.length;i++) 3c]b)n~Y  
{ gT0BkwIV  
nStartPos = input.readLong(); [BqHx5Xz(  
nEndPos = input.readLong(); z8SmkL  
} e%@~MQ-  
input.close(); 6/r)y+H  
} +#lM  
catch(IOException e){e.printStackTrace ();} ,D]QxbwZ  
catch(Exception e){e.printStackTrace ();} pgE}NlW  
} -ZRO@&tMD  
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private void processErrorCode(int nErrorCode) gy 3i+J  
{ rA5=dJ"I  
System.err.println("Error Code : " + nErrorCode); x7jC)M<k0  
} X.f>'0i  
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//停止文件下载 %yW3VL  
public void siteStop() D(AXk8Vub  
{ C/vIEYG4  
bStop = true; AGQ#$fh>7=  
for(int i=0;i<nStartPos.length;i++) YW_Q\|p]M  
fileSplitterFetch.splitterStop(); 1m:XR0P  
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} D6>2s\:>vp  
} CF&6J$ZBgJ  
//负责部分文件的抓取 \]2]/=2tLd  
**FileSplitterFetch.java \Zqng  
*/ mpuq 9)6  
package NetFox; YaKeq5%y  

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import java.io.*; QS` PpyBkd  
import java.net.*; jV>ra
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public class FileSplitterFetch extends Thread { 723bkJw V  
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String sURL; //File URL K;>9ZZtl  
long nStartPos; //File Snippet Start Position Jq&uF*!  
long nEndPos; //File Snippet End Position i|w81p^o  
int nThreadID; //Thread's ID 9F)z4  
boolean bDownOver = false; //Downing is over J'SZ  
boolean bStop = false; //Stop identical u09:Z{tL;@  
FileAccessI fileAccessI = null; //File Access interface -0$55pa/@:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E*V`":efS  
{ [E!oQVY  
this.sURL = sURL; aE&,]'6  
this.nStartPos = nStart; \?0&0;5  
this.nEndPos = nEnd; Tx|Ir+f6L  
nThreadID = id; 9`I _
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 +*ZO&yJQ^<  
} 6y+Kjd/D  
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@SJL\{_  
public void run() XQ9O$ ~q  
{ )}D'<^=#T  
while(nStartPos < nEndPos && !bStop) :PIF07$xl  
{ :km61  
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try{ }=gx#  
URL url = new URL(sURL); _=Z,E.EN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xjo5v*Pu  
httpConnection.setRequestProperty("User-Agent","NetFox"); /'].lp  
String sProperty = "bytes="+nStartPos+"-"; s>;v!^N?u  
httpConnection.setRequestProperty("RANGE",sProperty); P7nc7a  
Utility.log(sProperty); *1p|5!4c  
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InputStream input = httpConnection.getInputStream(); !sDh4jQ`  
//logResponseHead(httpConnection); ^?0DP>XA  
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byte[] b = new byte[1024]; 8$85^Of  
int nRead; k2c}3 MeP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6x h:/j3  
{ Sp@^XmX(S  
nStartPos += fileAccessI.write(b,0,nRead); <tF9V Jq  
//if(nThreadID == 1) J pFfzb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gn|F`F  
} M m[4yP%  
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Utility.log("Thread " + nThreadID + " is over!"); $@^pAP   
bDownOver = true; zEd0Tmt  
//nPos = fileAccessI.write (b,0,nRead); i]Fp..`v~  
} Q1O}ly}JS  
catch(Exception e){e.printStackTrace ();} ;> _$`  
} ORyE`h
 
} NO|KVZ~  
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//打印回应的头信息 8YZbP5'  
public void logResponseHead(HttpURLConnection con) T]t+E'sQ  
{ A )^`?m3  
for(int i=1;;i++) GN ]cDik  
{ T&%ux=Jt  
String header=con.getHeaderFieldKey(i); Kqp(%8mf  
if(header!=null) &Sl[lXE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #33fGmd[  
Utility.log(header+" : "+con.getHeaderField(header)); jhXkSj  
else Q<h-FW8z  
break; yaah*1ip[  
} 9K5pwC\$%  
} Rv#]I#O  
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public void splitterStop() :`-,Lbg  
{ u.mJQDTH  
bStop = true; jNLw=  
} AvxfI"sp  
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} b7NM#Hb
 
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/* )2V:  
**FileAccess.java eoai(&o0$  
*//文件访问(定位，写) (eCJ;%%k  
package NetFox; }`W){]{kO  
import java.io.*; J6U$qi  
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public class FileAccessI implements Serializable{ plb!.g  
rM .|1(u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u=/{cOJI6  
RandomAccessFile oSavedFile; tE@;X=  
long nPos; &j4xgh9  
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public FileAccessI() throws IOException ^aH\7J@Y  
{ 5jd,{<  
this("",0); R%Q@  
} b~'"^ Bts*  
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public FileAccessI(String sName,long nPos) throws IOException BF
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{ uT}' Y)m  
oSavedFile = new RandomAccessFile(sName,"rw"); 5]n[]FW  
this.nPos = nPos; V}dJ.I /#  
oSavedFile.seek(nPos); ?Cl%{2omO  
} |K.mP4CKY  
Qa.<K{m#?  
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public synchronized int write(byte[] b,int nStart,int nLen) (iL|Sq&}b  
{ f!s=(H;  
int n = -1; 1+9W+$=h2  
try{ POvP]G9'"  
oSavedFile.write(b,nStart,nLen); Z8rvWH9  
n = nLen; clNkph  
} `Jzp Sw  
catch(IOException e) W_kHj}dj,p  
{ kPVO?u
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e.printStackTrace (); LL2=&VK  
} UD8op]>L  
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return n; U-IpH+E  
} ~ vJ,`?  
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} c17_2 @N  
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/*  /% M/  
**SiteInfoBean.java @^T1
XX  
*/ _~piZmkG$  
package NetFox; "tB;^jhRs  
JKGc3j,+#  
Vm3v-=6  
public class SiteInfoBean { rd9e \%A  
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private String sSiteURL; //Site's URL j#+!\ft5  
private String sFilePath; //Saved File's Path S,Xnzrz  
private String sFileName; //Saved File's Name 1UE6 4Kl:S  
private int nSplitter; //Count of Splited Downloading File dYL"h.x  
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=>M^02
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public SiteInfoBean() r7b1-  
{//nSplitter的缺省值为5 5*1D$mxD"  
//default value of nSplitter is 5 C}_ ojcR  
this("","","",5); hRs&t,{&  
} !4^C #{$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K?BOvDW"`  
{ ',:*f8Jk  
sSiteURL= sURL; `[W[H(AjQ  
sFilePath = sPath; P*I}yPeb  
sFileName = sName; EL(nDv  
this.nSplitter = nSpiltter; 1IZ3=6  
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} d4?Mi2/jF  
22.8PO0  
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public String getSSiteURL() 6f\Lf?vF  
{ 0a}u;gt,4w  
return sSiteURL; jpO7'ivG  
} BK,{N0  
4iKgg[)7`=  
Mz~M3$$9n  
public void setSSiteURL(String value) OoA|8!CFa  
{ aFS,GiB  
sSiteURL = value; Q$="_y2cTA  
} hM{{\yZS  
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public String getSFilePath() Jo@|"cE=  
{ no< ^f]33  
return sFilePath; @>W(1mRi  
} Z@]e{zO  
. r[Hu40p  
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public void setSFilePath(String value) cd$m25CxC  
{ a{ ?`t|  
sFilePath = value; {TX]\ufG  
} z7Q?D^miy  
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public String getSFileName() ]%?YZn<{  
{
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return sFileName; 1T-8K
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} M#As0~y  
] :BX!<  
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public void setSFileName(String value) Q\ U:~g3  
{ iZaI_\"__  
sFileName = value; !f&Kf,#b`  
} ?kB2iU_f+  
N4L|;?  
^eR%N8Z  
public int getNSplitter() h-Fn?  
{ >(?
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return nSplitter; p;t
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} `kZ@Zmj#  
3td)'}  
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public void setNSplitter(int nCount) Q4f/Z  
{ Hhari!RXC  
nSplitter = nCount; 2@%$;.  
} <
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} ^OstR`U3  
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<xgTS[k  
/* PzA|t;*
  
**Utility.java ~~SwCXZ+b^  
*/ >i5acuth  
package NetFox; ;S57w1PbVA  
&:
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jF=gr$  
public class Utility { 1DvR[Lx%  
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public Utility() 'J6 M*vO  
{ D(h18  
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}RwSp!}C  
} S%yd5<%_  
a^=-Mp  
//线程睡眠 ; =X P&  
public static void sleep(int nSecond) yjhf   
{ :&:JTa1cv  
try{ TW[_Ko86  
Thread.sleep(nSecond); ?)`L$Vr=  
} 5lm<%  
catch(Exception e) d"6&AJ5a  
{ ,:Lb7bFv>  
e.printStackTrace ();
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j  
} |=$-Wu  
} xv&Q+HD  
q
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//日志 V\^EfQ  
public static void log(String sMsg) .R9IL-3fO  
{ [BT/~6ovrZ  
System.err.println(sMsg); Qt/8r*Oe  
} Z| V`B `  
EpFQ|.mQ  
WC|.g,9#  
public static void log(int sMsg) gMaN)ESqd4  
{ h
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System.err.println(sMsg); ^d~1E Er  
} hED=u/ql[  
} <j5NFJ9  
Oh'Y0_oB>  
%7gkNa  
/* ,{LG4qvP  
**TestMethod.java k&.Jk B"  
*/ US%
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package NetFox; DXa-rk8  
~R&;v3  
#_(jS+lP?k  
public class TestMethod { t| 'N+-T3  
`$B3X  
:@!ic
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public TestMethod() l?Fb ='#  
{ ///xx/weblogic60b2_win.exe @)-$kk*  
try{ y^}6!>Ou:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5<ux6,E1{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j'BMAn ?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ##EYH1P]  
fileFetch.start(); hYM@?/(q  
} Xa[?^P  
catch(Exception e){e.printStackTrace ();} ;\\@q"n%<  
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6p?JAT5  
} \@1=stK:F  
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public static void main(String[] args) ?HV`| Cw  
{ X_g 3rv1J  
new TestMethod(); I=.z+#Y  
} EoxQ */  
} e&qh9mlE  
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