http断点续传简单实现（java)

/* oN`khS]_v0  
**SiteFileFetch.java D  ,[yx='  
*/ !7p&n3dz  
package NetFox; QlS_{XV  
import java.io.*; T`9nY!  
import java.net.*; 6h0}ZM  
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public class SiteFileFetch extends Thread { '%YE#1*gH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6Cfsh<]b  
long[] nStartPos; //开始位置 %/qwqo`Q  
long[] nEndPos; //结束位置 z[y
  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A4rkwM  
long nFileLength; //文件长度 u'T-}95 V  
boolean bFirst = true; //是否第一次取文件 mA@!t>=oMq  
boolean bStop = false; //停止标志 =ADOf_n}  
File tmpFile; //文件下载的临时信息 Ejnk\8:  
DataOutputStream output; //输出到文件的输出流 B:Awy/XMi  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #T@k(Bz{L  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2\;/mQI2A  
{ z;_vl  
siteInfoBean = bean; |dDKO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ZT8LMPC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T|0d2aa  
if(tmpFile.exists ()) f>|<5zm#
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{ \xcf<y
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bFirst = false; KP7 {  
read_nPos(); ~Yc!~Rz  
} D4uAwmc  
else V^rL  
{ [B+:)i  
nStartPos = new long[bean.getNSplitter()]; c2?VjuB0  
nEndPos = new long[bean.getNSplitter()]; %?Q&a ]  
} 9ExI,  
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} 5:C>:pAV  
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public void run() 
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{ ZOpKi:\  
//获得文件长度 2e03m62*  
//分割文件 ,eWLig  
//实例FileSplitterFetch GLX{EG9Z  
//启动FileSplitterFetch线程 EVC]B}  
//等待子线程返回 ayQeT  
try{ drk BW}_  
if(bFirst) CGkx_E]  
{ B^/k`h6J  
nFileLength = getFileSize(); >Bu9
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if(nFileLength == -1) \9uK^oS  
{ wNn=JzP  
System.err.println("File Length is not known!"); %(W8WLz}  
} Nwe-7/Q  
else if(nFileLength == -2) ?%Ww3cU+J  
{ *M_^I)*L  
System.err.println("File is not access!"); <q>d@Foi  
} /+8VW;4|I  
else KY%{'"'u  
{ rs( e  
for(int i=0;i<nStartPos.length;i++) fre5{=@  
{ pLys%1hg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /J&ks>St  
} *N}$~N  
for(int i=0;i<nEndPos.length-1;i++) f=u
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{ E!BzE_|i  
nEndPos = nStartPos[i+1]; ~(7ct*U~  
} I)s_f5'  
nEndPos[nEndPos.length-1] = nFileLength; )Y9\>Xj7  
} x 4sIZe+  
} 0L1sF'ZN  
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cc:$$_'L  
//启动子线程 MvnQUZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; = ^Vp \  
for(int i=0;i<nStartPos.length;i++) rHk,OC  
{ WiZTE(NM`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E@n~ @|10  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lI+^}-<  
nStartPos,nEndPos,i); e+D]9wM8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >d *`K  
fileSplitterFetch.start(); 8S8UV(K0  
} O&yAFiCd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]61HQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T,rRE7  
nEndPos = " + nFileLength); ts}OE  
// fileSplitterFetch[nPos.length-1].start(); GZKYRPg  
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//等待子线程结束 $mE3 FJP>  
//int count = 0; RA;/ ?l  
//是否结束while循环 -sZb+2tDa  
boolean breakWhile = false; {K6Z.-.`  
R/*"N'nH-%  
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while(!bStop) ~G-W|>  
{ 9 wbQ$>G9  
write_nPos(); BV }CmU&DA  
Utility.sleep(500); YOj&1ymBZ  
breakWhile = true; &/ED.K  
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for(int i=0;i<nStartPos.length;i++) ^y KkWB*  
{ R5%CK_  
if(!fileSplitterFetch.bDownOver) [#RFdn<  
{ F",TP,X  
breakWhile = false; ",J&UTUh  
break; 12m-$/5n+  
} 'bz&m(!  
} 5]upfC6  
if(breakWhile) ~zG)<S"q  
break; hayJgkZ'  
}!R*Q`m  
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//count++; !{+.)%d'g  
//if(count>4) '`.-75T  
// siteStop(); v9Sk\9}S  
} 32?'jRN(ue  
c$^v~lQS  
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System.err.println("文件下载结束！"); NsSZ?ky  
} l|E4 7@#  
catch(Exception e){e.printStackTrace ();} 5J|S
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} v'b%m8  
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//获得文件长度 .`5|NUhN  
public long getFileSize() |+::sL\r  
{ qNP)oU92  
int nFileLength = -1; N6\rjYx+7  
try{ hf0(!C*  
URL url = new URL(siteInfoBean.getSSiteURL()); b;5j awG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i*m;kWu,  
httpConnection.setRequestProperty("User-Agent","NetFox"); e&U$;sS`  
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int responseCode=httpConnection.getResponseCode(); wytMoG\  
if(responseCode>=400)
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{ lS7L|  
processErrorCode(responseCode); 7aKI=;60.  
return -2; //-2 represent access is error c%^B '  
} \k`9s q  
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String sHeader; g?Nk-cg
  
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for(int i=1;;i++) R=D}([pi  
{ oH?:(S(   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u)I\R\N  
//Utility.log(in.readLine()); PpBptsb^|J  
sHeader=httpConnection.getHeaderFieldKey(i); %;v~MC@  
if(sHeader!=null) l9="ccM  
{ *A
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if(sHeader.equals("Content-Length")) :[328X2  
{ ".$kOH_:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'j, 
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break; 0XCAnMVo  
} :Dw_$  
} LjE3|+pJ  
else G?=&\fg_:  
break; jll:Rh(b  
} ,>7dIJqzw  
} 3*2~#dh=  
catch(IOException e){e.printStackTrace ();} :r hB=  
catch(Exception e){e.printStackTrace ();} <I tS_/z  
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Utility.log(nFileLength); ZvT,HJ0?  
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return nFileLength; kk6 !krZ  
} T$%QK?B  
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//保存下载信息（文件指针位置） rf4f'cUa  
private void write_nPos() y&5 O
)  
{
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try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); .Y]0gi8z  
output.writeInt(nStartPos.length); UE"v+GH  
for(int i=0;i<nStartPos.length;i++) ksOsJ~3)  
{ qve'Gm)  
// output.writeLong(nPos); La9}JvQoX  
output.writeLong(fileSplitterFetch.nStartPos); [BJzZ>cY  
output.writeLong(fileSplitterFetch.nEndPos); y$]<m+1  
} /7Pqy2sgE  
output.close(); xatq  
} DC*MB:c#U  
catch(IOException e){e.printStackTrace ();} @0P4pt;(  
catch(Exception e){e.printStackTrace ();} 9t)Hi qj  
} *8?2+)5"  
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//读取保存的下载信息（文件指针位置） -sKtT
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private void read_nPos() *nJ,|T  
{ ou~$XZ7oi  
try{ >4Tk#+%Jj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DGb1_2ZQ  
int nCount = input.readInt(); tJ K58m$  
nStartPos = new long[nCount]; .x,y[/[[)  
nEndPos = new long[nCount]; OzrIiahz/  
for(int i=0;i<nStartPos.length;i++) u%z'.#r;a  
{ (XmmbAbVom  
nStartPos = input.readLong(); `G\Gk|4;2  
nEndPos = input.readLong(); 0{z8pNrc  
} QJ(%rvn3  
input.close(); =LV-n  
} YCltS!k  
catch(IOException e){e.printStackTrace ();} d[,Rgdd@I  
catch(Exception e){e.printStackTrace ();} Sv/P:r _  
} K'J_AMBL  
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private void processErrorCode(int nErrorCode) pMHl<HH  
{ \zg R]|  
System.err.println("Error Code : " + nErrorCode); eg}g}a  
} Z+y'w#MZL  
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//停止文件下载 '%ilF1#  
public void siteStop() bS~Y
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{ b:hta\%/2  
bStop = true; ydO+=R0M  
for(int i=0;i<nStartPos.length;i++) EF\OM?R  
fileSplitterFetch.splitterStop(); WXmfh  
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} GLecB
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} a'jUM+D;  
//负责部分文件的抓取 TY %zw6 #p  
**FileSplitterFetch.java q#mL-3OQ  
*/ bH/4f93Nb  
package NetFox; 77[
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import java.io.*;
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import java.net.*; ,:L^v
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public class FileSplitterFetch extends Thread { bHRn}K+<}c  
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String sURL; //File URL iu8Q &Us0P  
long nStartPos; //File Snippet Start Position 96~y\X@x  
long nEndPos; //File Snippet End Position LJPJENtFIs  
int nThreadID; //Thread's ID T})q/oUqK  
boolean bDownOver = false; //Downing is over J~WT;s  
boolean bStop = false; //Stop identical +%\Ci!%b  
FileAccessI fileAccessI = null; //File Access interface CqC )H7A  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K<5yjG8&  
{ X/:
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this.sURL = sURL; &}e>JgBe0  
this.nStartPos = nStart; ,NZllnW  
this.nEndPos = nEnd; ANBuX6q  
nThreadID = id; EIQ3vOq6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fiWN^sTM  
} X[dfms;H  
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public void run() D
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{ _ncBq;j{  
while(nStartPos < nEndPos && !bStop) DKfpap}8u  
{ IKP_%R8.  
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try{ iZfZF  
URL url = new URL(sURL); Sdmz(R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PjBAf'  
httpConnection.setRequestProperty("User-Agent","NetFox"); DVhBZ!u9  
String sProperty = "bytes="+nStartPos+"-"; t adeG  
httpConnection.setRequestProperty("RANGE",sProperty); V~KWy@7  
Utility.log(sProperty); f?/OV*  
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InputStream input = httpConnection.getInputStream(); Wfd`v  
//logResponseHead(httpConnection); @, fvWNI  
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byte[] b = new byte[1024]; O DN
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int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R_/;U&R  
{ :$u[1&6  
nStartPos += fileAccessI.write(b,0,nRead);
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//if(nThreadID == 1) cKkH*0B5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~L<"]V+B  
} d'MZ%.#  
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Utility.log("Thread " + nThreadID + " is over!"); ),`jMd1`  
bDownOver = true; ,yNuz@^ P  
//nPos = fileAccessI.write (b,0,nRead); {0F/6GwUC  
} "t
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catch(Exception e){e.printStackTrace ();} f4.jWBF  
} "$(D7yFO  
} tL;.vR
x  
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//打印回应的头信息 ; k.
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public void logResponseHead(HttpURLConnection con) ui)mYR[8X  
{ Ix_w.f=8  
for(int i=1;;i++) k%~;mu"4}  
{ p:nl4O/  
String header=con.getHeaderFieldKey(i); Rq+7&%dy  
if(header!=null) BV@q@C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W*S4gPGM  
Utility.log(header+" : "+con.getHeaderField(header)); 7P3/Ky@6  
else LqD7SJ}/f  
break; ?Ybq]J\q  
} RYvcuA)  
} %,vq@..^  
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public void splitterStop() Sd^I>;  
{ d.w]\  
bStop = true; 6BA$v-VVU  
} ?`xF>P]M  
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} ,\ 1X\  
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/* ~v\ W[  
**FileAccess.java zMpvS rc  
*//文件访问(定位，写) t=}]4&Yp  
package NetFox; rZ(#t{]=!  
import java.io.*; .zdaY, U  
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public class FileAccessI implements Serializable{ 1ED7
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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 Z}0{FwW"4  
RandomAccessFile oSavedFile; M .6BFC  
long nPos; qZ>_{b0f  
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public FileAccessI() throws IOException {9|*au(K  
{ ;|XX^  
this("",0); 1mtYap4  
} tQNc+>7k+u  
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public FileAccessI(String sName,long nPos) throws IOException
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{ -32P}58R  
oSavedFile = new RandomAccessFile(sName,"rw"); i75\<X
 
this.nPos = nPos; 4KxuSI^q  
oSavedFile.seek(nPos); M]Vi]s  
} dKEy6
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public synchronized int write(byte[] b,int nStart,int nLen) 2Jiy`(P  
{ sbVEA  
int n = -1; KAE %Wwjr  
try{ qF(i1#  
oSavedFile.write(b,nStart,nLen); %e25Z.Se$  
n = nLen; a
"Iu!$&N  
} p3-~cr.LD  
catch(IOException e) dEMv9"`*!  
{ f-i5tnh  
e.printStackTrace (); :/SGB3gb1t  
} *^{j!U37s  
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return n; .EWjeVq  
} =ePwGm1:c  
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} DsxNg  
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lUq`tK8  
/* $SA @ "  
**SiteInfoBean.java LdiNXyyzet  
*/ O+'k4  
package NetFox; @Kt!uKrI  
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=C(BZ+-^  
public class SiteInfoBean { ]YZ_kc^(V;  
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private String sSiteURL; //Site's URL t6e6v=.Pg  
private String sFilePath; //Saved File's Path Y/m-EL  
private String sFileName; //Saved File's Name )iIsnM  
private int nSplitter; //Count of Splited Downloading File t vW0 W  
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BUi,+NdIk  
public SiteInfoBean() 7|Wst)_~j  
{//nSplitter的缺省值为5 ]3]B$  
//default value of nSplitter is 5 .8'uIA{_2  
this("","","",5); 32j#kJW  
} 9ec#'i=  
753gcY#i  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pox;NdX7  
{ Wo9=cYC)  
sSiteURL= sURL; ia.+<, $`S  
sFilePath = sPath; YGyw^$.w  
sFileName = sName; -`spu)  
this.nSplitter = nSpiltter; fK(:vwh  
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* >NML]#0  
} {
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public String getSSiteURL() ) .V,zmI  
{ X?r$o>db  
return sSiteURL; e&(Wn2)o  
} KF#qz2S  
E\Iz:ES^  
1"<{_&d1  
public void setSSiteURL(String value) meap;p  
{ S n~P1C  
sSiteURL = value; 9zBt a  
} g[ @Q iy  
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public String getSFilePath() VJr~h "[  
{ wB[ JFy"E  
return sFilePath; mH<|.7~0  
} 4/SltWU  
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public void setSFilePath(String value) 'wBOnGi6  
{ =b6G' O[  
sFilePath = value; uE,TEa9;  
} ^MhMYA  
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public String getSFileName()
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{
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return sFileName; V+|$H h8  
} ]P^3uXi  
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public void setSFileName(String value) cqb6]  
{ hJ4 A5m.  
sFileName = value; }U%E-:  
} `B3YP1  
o/RGzPR  
^#w9!I{4.  
public int getNSplitter() JV2[jo}0N  
{ PI*Z>VE
?  
return nSplitter; _$}@hD*R~  
} }g2l ni  
5!6iAS+I  
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public void setNSplitter(int nCount) !D 'A  
{ S->S
p  
nSplitter = nCount; 4;IZ}9|G  
} >;xkiO>Y  
} !0X"^VB  
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/* 94rx4"AN8;  
**Utility.java N45@)s!F9j  
*/ uE#i3( J  
package NetFox; 8rz,MsFR  
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public class Utility { qV$0 ";d  
%we! J%'Y]  
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public Utility() c-?0~A  
{ _z"\3hZ  
Z= pvoTY  
PB{5C*Y7^k  
} DxP65wU  
$*9:a3>zny  
//线程睡眠 l2LO,j}  
public static void sleep(int nSecond) cgQ2Wo7tCq  
{ HN&]`cr;  
try{ ef:Zi_o   
Thread.sleep(nSecond); 3-![%u  
} 
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catch(Exception e) o-A
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{  A1jA$  
e.printStackTrace (); d\ Xijy  
} dpcv'cRfw  
} r
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$! UEpQ  
//日志 p1\EC#Q  
public static void log(String sMsg) <2w41QZX  
{ UzkX;UA  
System.err.println(sMsg); l_&T)Ei  
} ?d)eri8,  
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c/G^}d%  
public static void log(int sMsg) 0t00X/  
{ .YIb ny1  
System.err.println(sMsg); -s:NF;"  
} j&,%v+x  
} S'q4va"  
04#r'UIF  
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/* e]l.m!,r  
**TestMethod.java {y>Kcfc/?E  
*/ 1ZfhDtK(  
package NetFox; -s6;IoG/  
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public class TestMethod {  ] 2lhJ  
@p7*JLO  
|w`Q$ c  
public TestMethod() MSS0Sx<f  
{ ///xx/weblogic60b2_win.exe !r_2b! dy  
try{ t. kOR<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H|B4.z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h4? 'd+
K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v6KF0mqA&  
fileFetch.start(); 4ko(bW#jL  
} =a./HCF  
catch(Exception e){e.printStackTrace ();} 7Dx<Sr!  
C5'#0}6i  
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} CC`Y r  
k*= #XbX  
@RI\CqFHR  
public static void main(String[] args) RD'i(szi?  
{ O8w|!$Q.  
new TestMethod(); G9a6
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} {rZ )!  
} JXF@b-c  
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