http断点续传简单实现（java)

/*  G 3Z"U  
**SiteFileFetch.java ,>;21\D  
*/ aZFpt/.d  
package NetFox; $DbnPZ2$  
import java.io.*; 17LhgZs&  
import java.net.*; 5 ~Wg=u<6  
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public class SiteFileFetch extends Thread { YKyno?m  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7EJ2 On  
long[] nStartPos; //开始位置 PTQ#8(_,  
long[] nEndPos; //结束位置 WR;1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HK;NR.D  
long nFileLength; //文件长度 LP2~UVq  
boolean bFirst = true; //是否第一次取文件 +jm,nM9  
boolean bStop = false; //停止标志 \T
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File tmpFile; //文件下载的临时信息 8Q'Emw |  
DataOutputStream output; //输出到文件的输出流 $%bSRvA  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EL 5+pt  
public SiteFileFetch(SiteInfoBean bean) throws IOException u#0snw~)/  
{ pgU[di  
siteInfoBean = bean; V;M_Y$`Lh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]PXM;w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A;oHji#*  
if(tmpFile.exists ()) ci0A!wWD  
{ Q]ersA8 V>  
bFirst = false; dSM\:/t  
read_nPos(); F.9}jd{  
} Un?
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else yW_yHSx;  
{ I2Xd"RHN  
nStartPos = new long[bean.getNSplitter()]; @\K[WqF$$q  
nEndPos = new long[bean.getNSplitter()]; g'"~'  
} LrB 0x>  
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} T5XXC1+  
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public void run() B*,6;lCjX  
{ AO#9XDEM  
//获得文件长度 19!?oeOU  
//分割文件 *1|7%*!8  
//实例FileSplitterFetch ACszx\[K3  
//启动FileSplitterFetch线程 +|A`~\@N  
//等待子线程返回 amBg<P`'_  
try{ Cf% qa
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if(bFirst) YT\`R  
{ ;%e&6  
nFileLength = getFileSize(); /*0t_  
if(nFileLength == -1) n]%-2`}(  
{ |[\;.gT K  
System.err.println("File Length is not known!"); N/4E ~^2  
} kAftW
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else if(nFileLength == -2) XT7m3M  
{ D"7}&Ry:  
System.err.println("File is not access!"); 55Ss%$k@  
} `TrWtSwv  
else )6"}M;v  
{ K-RmB4WI  
for(int i=0;i<nStartPos.length;i++)  RD$:.  
{ %OQdUH4x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2W AeSUX  
} .-gJS-.c  
for(int i=0;i<nEndPos.length-1;i++) D,#UJPyg  
{ #{i*9'  
nEndPos = nStartPos[i+1]; waMF~#PJlt  
} WAu
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nEndPos[nEndPos.length-1] = nFileLength; NxP(&M(  
} 5pQpzn=  
} !eX0Q 2  
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9"~ FKMN  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; DAn2Pqf  
for(int i=0;i<nStartPos.length;i++) \"lz,bT  
{ HC iRk1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {j2V k)\[i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H:fKv7XL  
nStartPos,nEndPos,i); I}C2;[aB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I8xdE(o8+  
fileSplitterFetch.start(); (t&RFzE?G  
} K_i|cYGV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a5*r1,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ImXYI7PL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \&"C  
nEndPos = " + nFileLength); 1%Xh[  
// fileSplitterFetch[nPos.length-1].start(); wh$bDTCj  
SNj-h>&Mha  
uwwR$ (\7  
//等待子线程结束 gOF^?M11x  
//int count = 0; (7 I|lf e  
//是否结束while循环 xSY"Ru  
boolean breakWhile = false; 0 R6:3fV6R  
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while(!bStop) `v*HH}aDO  
{ Wjb_H (D  
write_nPos(); R)NSJ-A!2  
Utility.sleep(500); $n<a`PdH  
breakWhile = true; h"FI]jK|}  
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for(int i=0;i<nStartPos.length;i++) g'.OzD  
{ ;1k&}v&  
if(!fileSplitterFetch.bDownOver) rA~f68h|  
{ Z?
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breakWhile = false; BJ|l  
break; fU>l:BzJK  
} 6bm7^e(  
} nFnM9 pdMK  
if(breakWhile) ;;0'BdsL`  
break; |UTajEL  
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//count++; 2`o @L  
//if(count>4) B+W7zv  
// siteStop(); oE '
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} xf,[F8 2y  
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System.err.println("文件下载结束！"); z33UER"  
} CG1MT(V7?  
catch(Exception e){e.printStackTrace ();} =%<=Bn  
} hGtz[u#p  
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//获得文件长度 <KMCNCU\+  
public long getFileSize() wQ33Gc  
{ ] Q5:JV  
int nFileLength = -1; .psb#4  
try{ ,`geOJn'  
URL url = new URL(siteInfoBean.getSSiteURL()); s%)f<3=a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;Y7'U rn  
httpConnection.setRequestProperty("User-Agent","NetFox"); #Y7jNrxE
  
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int responseCode=httpConnection.getResponseCode(); sT^R0Q'>  
if(responseCode>=400) (`(D $%  
{ J[ZHAnmPH  
processErrorCode(responseCode); :nx+(xgw  
return -2; //-2 represent access is error o=rR^Z$G   
}
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String sHeader; eHr0],  
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for(int i=1;;i++) 7zu\tCWb  
{ f,G*e367:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `~XksyT  
//Utility.log(in.readLine()); ~F"S]  
sHeader=httpConnection.getHeaderFieldKey(i); j iKHx_9P  
if(sHeader!=null) o/Ismg-p  
{ 8iIp[9~=  
if(sHeader.equals("Content-Length")) \U:OQ.e  
{  2%@tnk|@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ajSB3}PN  
break; M@[W"f Wq  
} &gCGc?/R#  
} y3~`qq  
else Q(& @ra!{  
break; Ark]>4x>  
} 8T1`9IT
l:  
} &%2^B[{  
catch(IOException e){e.printStackTrace ();} lHM+<Z  
catch(Exception e){e.printStackTrace ();} XvI~"}  
6 f*:;  
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Utility.log(nFileLength); ]0UYxv%]  

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return nFileLength; $;^|]/-  
} $Cz2b/O  
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//保存下载信息（文件指针位置） 1KZigeHXI  
private void write_nPos() oJa}NH   
{ #Z1%XCt  
try{ 50
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ;EBKzB  
output.writeInt(nStartPos.length); {o~TbnC  
for(int i=0;i<nStartPos.length;i++) ?t'V5$k\  
{ #D9.A7fCc5  
// output.writeLong(nPos); \,13mB6  
output.writeLong(fileSplitterFetch.nStartPos); 
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output.writeLong(fileSplitterFetch.nEndPos); }u8(7  
} uWJJ\  
output.close(); u8c@q'_  
} Sr \y1nt  
catch(IOException e){e.printStackTrace ();} #B\s'j[A"  
catch(Exception e){e.printStackTrace ();} 2"D4q(@  
} k A3K  
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t4oD> =,92  
//读取保存的下载信息（文件指针位置） <tvLKx  
private void read_nPos() (.UU40:t  
{ n.g-%4\q  
try{ 2E1`r@L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f2e;N[D  
int nCount = input.readInt(); D$>!vD'  
nStartPos = new long[nCount]; 8i',~[  
nEndPos = new long[nCount]; I8XP`Ccq  
for(int i=0;i<nStartPos.length;i++) qur2t8gnxq  
{ lie,A  
nStartPos = input.readLong(); ,zgz7  
nEndPos = input.readLong(); Ch]d\GM  
} +zh\W9  
input.close(); UVux[qX<  
} lT
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catch(IOException e){e.printStackTrace ();} ao)';[%9s  
catch(Exception e){e.printStackTrace ();} Gwk$<6E  
} /ZyMD(_J  
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private void processErrorCode(int nErrorCode) sJLOz>  
{ u\ _yjv#  
System.err.println("Error Code : " + nErrorCode); e|oMbTZ5m  
} &dtst??  
)#i@DHt=  
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//停止文件下载 cF 5|Pf  
public void siteStop() xf&[QG+Ef  
{ 1["i,8zB  
bStop = true; w=#'8ZuU  
for(int i=0;i<nStartPos.length;i++) \-yI dKj  
fileSplitterFetch.splitterStop(); ].s;Yxz  
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} ]EKg)E  
} Z"VP<-  
//负责部分文件的抓取 U~D~C~\2;  
**FileSplitterFetch.java 0B(s+#s  
*/ uE.BB#  
package NetFox; _M%>Qm  
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import java.io.*; OKh0m_ )7  
import java.net.*; +ydd"`  
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public class FileSplitterFetch extends Thread { +(2$YJ35  
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String sURL; //File URL m\qeYI6,Z  
long nStartPos; //File Snippet Start Position Gko"iO#  
long nEndPos; //File Snippet End Position H
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int nThreadID; //Thread's ID 4Kch=jt4#  
boolean bDownOver = false; //Downing is over [2-n*a(q  
boolean bStop = false; //Stop identical Oa/zEH  
FileAccessI fileAccessI = null; //File Access interface P<IDb%W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :^ywc O   
{ 7?yS>(VmT  
this.sURL = sURL; K T0t4XPM  
this.nStartPos = nStart; AJ%E.+@=r  
this.nEndPos = nEnd; "AUSgVE+h  
nThreadID = id; u9~5U9]O%6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S L 5k^|  
} G:1d6[Q5{  
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public void run() R ABw(b  
{ Tc(=J7*r&  
while(nStartPos < nEndPos && !bStop) Wh i#Ii~  
{ %[|^
7  
42
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try{ l~"T>=jq3  
URL url = new URL(sURL); SAdT#0J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2 `>a(  
httpConnection.setRequestProperty("User-Agent","NetFox"); BP9#}{kE  
String sProperty = "bytes="+nStartPos+"-"; %rb$tKk  
httpConnection.setRequestProperty("RANGE",sProperty); )I&.6l!#  
Utility.log(sProperty); ~)f^y!PMQ  
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InputStream input = httpConnection.getInputStream(); #DgHF*GG+>  
//logResponseHead(httpConnection); e%cTFwX?n  
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byte[] b = new byte[1024]; sex\dg<  
int nRead; > T*`Y0P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ketp9}u  
{ bVzi^R"  
nStartPos += fileAccessI.write(b,0,nRead); AY5iTbL1  
//if(nThreadID == 1) ;~<To9O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KFbB}oId  
} 3'.@aMA@  
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*:yG)J 3F  
Utility.log("Thread " + nThreadID + " is over!"); k^Qf
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bDownOver = true; N#l2wT  
//nPos = fileAccessI.write (b,0,nRead); os{ iY  
} ol"|?*3q  
catch(Exception e){e.printStackTrace ();} U1r]e%df)  
} ~Fuq{e9`  
} XY| y1L 3[  
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//打印回应的头信息 &1Ndi<Y^  
public void logResponseHead(HttpURLConnection con) _94 W@dW  
{ ??"_o3  
for(int i=1;;i++) YHEn{z7  
{ Ef#LRcG-Z  
String header=con.getHeaderFieldKey(i); d[_26.
 
if(header!=null) pbAL&}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1x|3|snz)  
Utility.log(header+" : "+con.getHeaderField(header)); &MSU<S?1  
else lBbb7*Ljt<  
break; P)K$+oo  
}
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} `sKyvPtG  
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public void splitterStop() MOD&3>NI  
{ =3
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bStop = true; M<Wi:r:  
} 9;#RzelSp  
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} y`va6 %u{  
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/* ]B3](TH"  
**FileAccess.java #r9+thyC  
*//文件访问(定位，写) <(KCiM=E$  
package NetFox; -iiX!@  
import java.io.*; _uO$=4Sd  
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\!\:p/f  
public class FileAccessI implements Serializable{ 0 SSdp<  
59oTU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K[y")ooE<j  
RandomAccessFile oSavedFile; }i!+d,|f  
long nPos; w||t3!M+n  
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public FileAccessI() throws IOException Q|)>9m!tt  
{ %NQ%6B  
this("",0); ,LA'^I?  
} <uuumi-!%G  
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public FileAccessI(String sName,long nPos) throws IOException 6RbDc*  
{ |3FI\F;^q  
oSavedFile = new RandomAccessFile(sName,"rw"); 9F807G\4Qt  
this.nPos = nPos; 4fKvB@O@.  
oSavedFile.seek(nPos); 9;L4\  
} ;3/}"yG<p  
^i8,9T'=  
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public synchronized int write(byte[] b,int nStart,int nLen)  NAD^1
0  
{ 1)= H2
n4)  
int n = -1; y8$3kXh  
try{ |1%%c %  
oSavedFile.write(b,nStart,nLen); t+KW=eW  
n = nLen; %!\=$s}g  
} 5b:1+5iF-  
catch(IOException e) ?V2P]|  
{ 9&* 7+!  
e.printStackTrace (); STnMBz7  
} 4C`RxQJM  
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b;VI
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return n; ''9]`B,:a0  
} zn>lF  
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} \)dp  
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/* f4p*!e  
**SiteInfoBean.java 0Ye/
 
*/ 0hoMf=bb$  
package NetFox; {LiJ=Ebt  
1vo3aF  
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public class SiteInfoBean { |>(Vo@  
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private String sSiteURL; //Site's URL T)e2IXGN  
private String sFilePath; //Saved File's Path >l 0aME@-0  
private String sFileName; //Saved File's Name (/uN+  
private int nSplitter; //Count of Splited Downloading File H}r]j\  
zCJ"O9G<V  
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public SiteInfoBean() 9C \}bT  
{//nSplitter的缺省值为5 ]lA}5  
//default value of nSplitter is 5 2@MpWj4  
this("","","",5); B5 /8LEWw  
} "1gIR^S%9  
s#5#WNzP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) diNSF-wi,,  
{ V<WWtu;3  
sSiteURL= sURL; p|gVIsg[-e  
sFilePath = sPath; C1{Q 4(K%  
sFileName = sName; -Cvd3%Jje  
this.nSplitter = nSpiltter; |vd|;" `  
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cy@oAoBq  
} )$p36dWl  
#fF5O2E'3  
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public String getSSiteURL() ~EmK;[Z  
{ |\Gkhi>;  
return sSiteURL; f=91 Z_M  
} Q.$/I+&j  
P>q
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#^RIp>NN9  
public void setSSiteURL(String value) nP*DZC0kE&  
{ 06HU6d,  
sSiteURL = value; ?MywA'N@x  
} .~I:Hcf/  
:Jyr^0`J  
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public String getSFilePath() GdC=>\]  
{ <!t;[ie?y  
return sFilePath; Gu{1%bb#kL  
} fUvXb>f,  
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public void setSFilePath(String value) Pjq9BK9p  
{ *As"U99(  
sFilePath = value; J,v024TM  
} }{:Jj/d p  
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public String getSFileName() V?t*c [  
{ &u9,|n]O9  
return sFileName; ipu~T)
}  
} YP!}Bf  
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9/8+R%  
public void setSFileName(String value) V9ZM4.,OCN  
{ 6 [bQ'Ir^8  
sFileName = value; i=^6nwD&  
} _l)3pm6  
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public int getNSplitter() : HU|BJ>  
{ qCVb-f  
return nSplitter; w:I!{iX
  
} _$
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iPCn-DoIS  
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public void setNSplitter(int nCount) w?_'sP{pd  
{ F+5 5p8  
nSplitter = nCount; 2 .Xx)(>  
} DIYR8l}x  
} S^1ZsD.  
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a
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/* ]/p>p3@1C  
**Utility.java EFU)0IAL[  
*/ ENA"T-p  
package NetFox; w}/+3z  
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public class Utility { 18~jUYMV  
9h+TO_T@F  
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public Utility() 'o=DGm2H  
{ ',+Zqog92  
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} r0f&n;0U4  
d8Cd4qIXX  
//线程睡眠 >}Mw"   
public static void sleep(int nSecond) `o{_+Li9  
{ c=-qbG0`  
try{ 1"t9x.  
Thread.sleep(nSecond); YajAz5N  
} ( ?e Et&  
catch(Exception e) jU 3ceXV  
{ ijcF[bmE  
e.printStackTrace (); K{Nj-Rqd  
} mDt!b6N/  
} ]#S<]vA  
18j>x3tn  
//日志 Jzp|#*~$E  
public static void log(String sMsg) $BLd>gTzmv  
{ /&qE,>hd.+  
System.err.println(sMsg);
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} wKpD++k  
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o=zl{tZV  
public static void log(int sMsg) UZ-pN_!Z:  
{ KAVkYL0  
System.err.println(sMsg); H7drDw  
} \,m*CYs`  
} hZ|0<u  
+s7w@  
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/* ',D%,N}J  
**TestMethod.java h*hkl#  
*/ @I&k|\  
package NetFox; gLFSZ  
mU[  
[Ak
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public class TestMethod { XE0b9q954  
re4z>O*  
:"nh76xg<  
public TestMethod() l"h6e$dP  
{ ///xx/weblogic60b2_win.exe /,<s9 :  
try{ 6\UIp#X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t8lGC R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "fN 6
_
*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oBnes*  
fileFetch.start(); YJDJj x  
} AnE] kq u  
catch(Exception e){e.printStackTrace ();} @d0~'_vtB  
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[T3%Xt'4  
} 4B[uF/[  
s`yg?CR`,  
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public static void main(String[] args) WXf[W  
{ LF
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new TestMethod(); m}beT
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} !F Zg' 9  
} A&jR-%JG  
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