http断点续传简单实现（java)

/* 8t9sdqM/C  
**SiteFileFetch.java P^VV8Z>\&  
*/ HgduH:
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package NetFox; "c1vW<;  
import java.io.*; %D e<H*  
import java.net.*; \'BKI;  
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public class SiteFileFetch extends Thread { q'",70"\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 };29'_.."x  
long[] nEndPos; //结束位置 Kze\|yJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z4H!b+   
long nFileLength; //文件长度 D-~
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boolean bFirst = true; //是否第一次取文件 TS-m^Y'R  
boolean bStop = false; //停止标志 |~#!e}L(  
File tmpFile; //文件下载的临时信息 G4=%<+
  
DataOutputStream output; //输出到文件的输出流 HPtaW:J  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） V@e0VV3yx%  
public SiteFileFetch(SiteInfoBean bean) throws IOException /rKrnxw  
{ 1B,RRHXn6  
siteInfoBean = bean; Kd7OnU  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SYa!IL-B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2R:['QT  
if(tmpFile.exists ()) NVJvCs)3f  
{ "AUY+ LN  
bFirst = false; ^9qncvV
 
read_nPos(); ;l}TUo  
} vJmE}  
else [rE,fR   
{ l&;#`\s!V  
nStartPos = new long[bean.getNSplitter()]; z}u  
nEndPos = new long[bean.getNSplitter()]; qhLe[[>  
} wyvs#T  
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} f0MHh5  
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public void run() \HTXl]  
{ 6i{W=$RQ  
//获得文件长度 }w"laZ*  
//分割文件 lZ/Yp~2S  
//实例FileSplitterFetch Kax85)9u  
//启动FileSplitterFetch线程 %8hhk]m\b>  
//等待子线程返回 Gq+!%'][P  
try{ =GFlaGD  
if(bFirst) V&)-u(s_S/  
{ *hFT,1WE=+  
nFileLength = getFileSize(); vF1]L]z:?  
if(nFileLength == -1) !mq+Oz~  
{ gd/W8*NFR  
System.err.println("File Length is not known!"); l,,5OZw  
} 9K FWa0G  
else if(nFileLength == -2) L!-T`R8'c  
{ \CU.'|X  
System.err.println("File is not access!"); >E[cl\5$E  
} 6M259*ME  
else %hcY [F<  
{ v3.JG]zLpP  
for(int i=0;i<nStartPos.length;i++) eUx|_*`  
{ Y~fds#y0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u=RF6V|  
} =;^2#UxXA&  
for(int i=0;i<nEndPos.length-1;i++) ]7c715@  
{ e@=Bl-  
nEndPos = nStartPos[i+1]; } Tp!Ub\Cc  
} q$>At}4  
nEndPos[nEndPos.length-1] = nFileLength; )6IO)P/Q~  
} }$81FSKh  
} mA3C)V  
S%g`X  
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//启动子线程 NqlG=pu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8;Yx a8ie  
for(int i=0;i<nStartPos.length;i++) p
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{ F4Z+)'oDr,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o D:
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \BUr2]  
nStartPos,nEndPos,i); xNE<$Bz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !XzRV?Ih;  
fileSplitterFetch.start(); R9fM9  
} %'k^aqFL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oy#Qj3M8=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RzFv``g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", W@#)8];>  
nEndPos = " + nFileLength); krI<'m;a  
// fileSplitterFetch[nPos.length-1].start(); ~/iE  
o;
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//等待子线程结束 ?5jkb  
//int count = 0; XQHvs{Po  
//是否结束while循环 A;q}SO%b  
boolean breakWhile = false; WPpl9)Qc  
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while(!bStop) ;la(Q~#  
{ "P"~/<:)  
write_nPos(); ?_}[@x  
Utility.sleep(500); MXSPD#gN  
breakWhile = true; bC)diC  
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*siS4RX2  
for(int i=0;i<nStartPos.length;i++) |*i0h`a  
{ GC~Tfrf=r  
if(!fileSplitterFetch.bDownOver) T>.*c6I b  
{ Abd&p N  
breakWhile = false; !1w=_  
break; *<"xF'C  
} Xr6UN{_-  
} F{B__Kf  
if(breakWhile) WFsa8qv  
break; NuLQkf)  
28>gAz.#  
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//count++; Mw*R~OX  
//if(count>4) /mo
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// siteStop(); (9{)4[3MAG  
} &v'e;W  
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System.err.println("文件下载结束！"); =Y?M#3P.I  
} [8(e`6xePb  
catch(Exception e){e.printStackTrace ();} Qpe&_.&RE  
} XGbtmmQG  
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//获得文件长度 pg [F{T<  
public long getFileSize() xQ-]Iw5  
{ -c~nmPEG6  
int nFileLength = -1; {: T'2+OH>  
try{ gH(,>}{^K  
URL url = new URL(siteInfoBean.getSSiteURL()); K8ecSs}}J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b'3w.%^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Oyz/P(p  
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int responseCode=httpConnection.getResponseCode(); w|OMT>.  
if(responseCode>=400) v\'Eo*4  
{ Pp*|EW 1  
processErrorCode(responseCode); WIa4!\Ky!  
return -2; //-2 represent access is error \|L ~#{a  
} vxzh|uF  
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String sHeader; z v*hA/  
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for(int i=1;;i++) Rs$k3
  
{ *&Np
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U^-:qT;CX  
//Utility.log(in.readLine()); BlF>TI%2  
sHeader=httpConnection.getHeaderFieldKey(i); N2 wBH+3w  
if(sHeader!=null) KnaQhZ  
{ }*4XwUM e  
if(sHeader.equals("Content-Length")) D'$ki[{,  
{ vSb$gl5H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !iN=py  
break; 4onRO!G,  
} w4\b^iJz  
} f R$E*Jd  
else /. k4Y  
break; d3v5^5kU  
} \tc4DS  
} suC]  
catch(IOException e){e.printStackTrace ();} _VLc1svv  
catch(Exception e){e.printStackTrace ();} )$p<BLU  
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Utility.log(nFileLength); Rq-BsMX!A  
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return nFileLength; \DI%/(?  
} %5?qS`/c(  
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//保存下载信息（文件指针位置） _z4c7_H3  
private void write_nPos() ^oDCF  
{  yr9%,wwN  
try{ W3Oj6R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u,mC`gz  
output.writeInt(nStartPos.length); 4D=p#KZ  
for(int i=0;i<nStartPos.length;i++) gXBC= ?jl  
{ Q
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// output.writeLong(nPos); >k)}R|tJ  
output.writeLong(fileSplitterFetch.nStartPos); &ejJf{id  
output.writeLong(fileSplitterFetch.nEndPos); L #c*)  
} 1S/KT4  
output.close(); #EQwl6  
} u/-ul  
catch(IOException e){e.printStackTrace ();} d:cs8f4>  
catch(Exception e){e.printStackTrace ();} 2+y<&[A8U  
} ];P$w.0  
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//读取保存的下载信息（文件指针位置） e"Kg/*Ji1  
private void read_nPos() Y3KKskhLx  
{ .
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try{ E&ou(Q={  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @0H}U$l  
int nCount = input.readInt(); 1AiqB Rs  
nStartPos = new long[nCount]; _+73Y'  
nEndPos = new long[nCount]; Y7g
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for(int i=0;i<nStartPos.length;i++) lf3QMr+  
{ <Yif-9  
nStartPos = input.readLong(); f86
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nEndPos = input.readLong(); =m]|C1x  
} 5$9g4  
input.close(); ye!}hm=w  
} lJ1_Zs `  
catch(IOException e){e.printStackTrace ();} 0/z=G!z\  
catch(Exception e){e.printStackTrace ();}
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} hUN]Lm6M  
*M6' GT1%c  
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private void processErrorCode(int nErrorCode) ^oaFnzJdf  
{ j:ze5FA+  
System.err.println("Error Code : " + nErrorCode); s~(!m. R  
} Hs,pY(l^  
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6^_:N1@  
//停止文件下载 I.#V/{J  
public void siteStop() n3Uw6gLD  
{ CEbZj z|  
bStop = true; 4B?8$&b  
for(int i=0;i<nStartPos.length;i++) $3.hZx>  
fileSplitterFetch.splitterStop(); c%,@O&o  
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} 2UqLV^ZY  
} EMK>7 aks  
//负责部分文件的抓取 $d\]s]}`  
**FileSplitterFetch.java ^I2+$  
*/ D2<(V,h9  
package NetFox; #2AKO/  
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import java.io.*; N1dv}!/*.+  
import java.net.*; B'sgCU  
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public class FileSplitterFetch extends Thread { oZVq}}R  
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String sURL; //File URL 9Q)9*nHe  
long nStartPos; //File Snippet Start Position qkHdr
2  
long nEndPos; //File Snippet End Position Y'n+,g  
int nThreadID; //Thread's ID j'xk[bM  
boolean bDownOver = false; //Downing is over vq(ElXTO  
boolean bStop = false; //Stop identical 9&]g2iT P  
FileAccessI fileAccessI = null; //File Access interface %<[?;  
+q*Cw>t /  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G_m$W3 zS  
{ aS2Mx~  
this.sURL = sURL; 6ooCg>9/Z  
this.nStartPos = nStart; <<#j?%  
this.nEndPos = nEnd; ~%.<rc0  
nThreadID = id; oXW51ty  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J9buf}C[  
} xb6y=L  
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public void run() VH*4fcT'D  
{ y+jOk6)W75  
while(nStartPos < nEndPos && !bStop) T-.Q  
{ CSu}_$wC#  
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try{ mEh([ZnY  
URL url = new URL(sURL); CGYZEPRR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jEaU;  
httpConnection.setRequestProperty("User-Agent","NetFox"); /^Ckk  
String sProperty = "bytes="+nStartPos+"-"; Jw-?7O  
httpConnection.setRequestProperty("RANGE",sProperty); MTyBGrs(  
Utility.log(sProperty); :_,oD  
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InputStream input = httpConnection.getInputStream(); 4xYW?s(  
//logResponseHead(httpConnection); Dej_(Dz_S  
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byte[] b = new byte[1024]; = ^NTHc^*  
int nRead; 16pk4f8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )c;zNs  
{ 1\XR6q:2  
nStartPos += fileAccessI.write(b,0,nRead); >5%;NI5 G  
//if(nThreadID == 1) >)+-:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3_5]0:?]-  
} ZjB]pG+  
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Utility.log("Thread " + nThreadID + " is over!"); TAE@KSPvo  
bDownOver = true; }I )%Gw  
//nPos = fileAccessI.write (b,0,nRead); V{D~e0i/v  
} BSyl!>G6n8  
catch(Exception e){e.printStackTrace ();} sFrerv&0  
} eI#b%h  
} "kdmqvTHK0  
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' 5F3,/r  
//打印回应的头信息 KFuPgp  
public void logResponseHead(HttpURLConnection con) ^F="'/Pq[  
{ dm:2:A8^  
for(int i=1;;i++) dX^d\ wX  
{ awC:{5R8v  
String header=con.getHeaderFieldKey(i); K6BP~@H_D  
if(header!=null) }M0GPpv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g]mR
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Utility.log(header+" : "+con.getHeaderField(header)); rYn)E=FG/  
else 8mh@C6U  
break; .,l4pA9v  
} J]-z7<j']  
} B3';Tcs  
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public void splitterStop() 4DTT/ER'qA  
{ C{<dzooz  
bStop = true; +9fQ YJBA  
} f_m~_`m  
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} {^jRV@  
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/* iTu~Y<'m  
**FileAccess.java c|2+J:}p  
*//文件访问(定位，写) ^VOA69n>$  
package NetFox; ahmxbv3f=5  
import java.io.*; t`!@E#VK  
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public class FileAccessI implements Serializable{ ]*&`J4i  
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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 ;4s7\9o  
RandomAccessFile oSavedFile; ny'wS  
long nPos; VEGp!~D  
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$ vt6~nfI  
public FileAccessI() throws IOException Sa 8T'%W  
{ twr-+rm2  
this("",0); 6$5?%ZLJ  
} xWuvT,^  
2,^U8/  
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public FileAccessI(String sName,long nPos) throws IOException 14S_HwX  
{ {=Z _L?j  
oSavedFile = new RandomAccessFile(sName,"rw"); m2j]wUh"  
this.nPos = nPos; z0-[ RGg  
oSavedFile.seek(nPos); !;U;5e=0  
} 87ptab@  
k+%c8w 9  
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public synchronized int write(byte[] b,int nStart,int nLen) g}gOAN3.  
{ ? \p,s-CR:  
int n = -1; 6BY(Y(z  
try{ dhCrcYn  
oSavedFile.write(b,nStart,nLen); m> YjV>5  
n = nLen; k8S`44vj  
} Dwa.ZY}-  
catch(IOException e) =}OcMM`f  
{ 3T)_(SM"  
e.printStackTrace (); 5STk"  
} {9;x\($&a  
8}.V[,]6  
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return n; r=c
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}
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} {osadXdC  
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/* rk7d7`V  
**SiteInfoBean.java ZO*?02c  
*/
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package NetFox; a2.@Zyz  
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public class SiteInfoBean { )>r sX)  
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private String sSiteURL; //Site's URL _`d=0l*8  
private String sFilePath; //Saved File's Path D`hg+64}  
private String sFileName; //Saved File's Name 8\BYm|%aa  
private int nSplitter; //Count of Splited Downloading File _BPp=(|  
,wB)hp  
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public SiteInfoBean() [+(fN  
{//nSplitter的缺省值为5 c1}i|7/XSi  
//default value of nSplitter is 5 ewOe A|  
this("","","",5); \o<&s{6L  
} ?O.'_YS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 30<3DA_P  
{ Q4B(NYEu(  
sSiteURL= sURL; H|I.h{:  
sFilePath = sPath; n<3{QqF  
sFileName = sName; DP08$Iq  
this.nSplitter = nSpiltter; 
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} 0RGqpJxk  
CQh6;[\:  
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public String getSSiteURL() 5$%CRm  
{ ~zcB@; :  
return sSiteURL; CJf4b:SY@  
} a'|/=$  
n|Gw?@CU7  
&]jCoBj+_  
public void setSSiteURL(String value) w|( ix;pK  
{ '~n=<Y  
sSiteURL = value; 8ps1Q2|  
} >d<tcaB  
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public String getSFilePath() $&KiN82,  
{ k5
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return sFilePath; i/aj;t
  
} o!sHK9hvJ)  
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public void setSFilePath(String value) 5@yBUwMSj  
{ ,.TwM;w=  
sFilePath = value; #)z7&nD  
} l;vA"b=]  
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n{E9p3
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public String getSFileName() =0_((eXwf  
{ l(uV@_3  
return sFileName; )@E'yHYO>  
} TQsTL2a  
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l^;=0UR_  
public void setSFileName(String value) *$9Rb2}kK  
{ t&
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sFileName = value; b0h>q$b  
} `V=F>s$W  
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public int getNSplitter() ^9`~-w  
{ }-%:!*bLj  
return nSplitter; i?IV"*Ob1N  
} g]m}@b6(h  
Mk|*=#e;  
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public void setNSplitter(int nCount) Vh8RVFi;c  
{ ](SqLTB+?  
nSplitter = nCount; ]tc Cr;  
} .y2np  
} 4]m?8j) 6b  
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/* g7
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**Utility.java .7r$jmuFs  
*/ ^=,N] j  
package NetFox; *%jd>e7d  
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public class Utility { *vP:+]  
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public Utility() &d&nsQ
 
{ M =6  
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} R\:t 73  
t2#zQ[~X!  
//线程睡眠 A=l1_8,`h  
public static void sleep(int nSecond) SS"Z>talw  
{ h f9yK6  
try{ QIu!o,B  
Thread.sleep(nSecond); %tZ[wwt  
} ;7bY>zc(w  
catch(Exception e) /*hS0xN*  
{ 7,,#f&jP  
e.printStackTrace (); ~_W>ND  
} Jec<1|  
} .tt=\R  
#PZBh  
//日志 w$FN(BfA  
public static void log(String sMsg) "MU)8$d  
{ g%2twq_  
System.err.println(sMsg); Zm#qW2a]P  
} <G#z;]N  
{6brVN.V  
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public static void log(int sMsg) r:9H>4m  
{ q.69<Rs  
System.err.println(sMsg); ["XS|"DM  
} R4Si{J*O  
} f f_| 3G  
62{[)jt{  
W!4xE  
/* kG|pM54:^  
**TestMethod.java HK!Vd_&9,  
*/ Y~uqKb;A  
package NetFox; v9+1[Y";  
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?,Zc{  
public class TestMethod { {#J1D*?
$"  
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public TestMethod() 9Qhk~^ngg  
{ ///xx/weblogic60b2_win.exe /S\y-M9  
try{ 8WRxM%gsH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NzuH&o][  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B(U0 ~{7a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `8N],X  
fileFetch.start(); hV>@qOl '  
} /e4#DH  
catch(Exception e){e.printStackTrace ();} ky98Bz%  
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} }%I)bU  
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public static void main(String[] args) um$K^  
{ Afq?Ps+  
new TestMethod(); ~\D H[Mt  
} gw`}eA$  
} <6) w  
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