http断点续传简单实现（java)

/* z,nRw/o  
**SiteFileFetch.java 0;Y_@UVj  
*/ A$RN7#  
package NetFox; A"V3g`dP  
import java.io.*; Ed|
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import java.net.*; q_8qowu"  
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public class SiteFileFetch extends Thread { GYiUne$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %@U<|9 %ua  
long[] nStartPos; //开始位置 KM|[:v  
long[] nEndPos; //结束位置 P%smX`v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mg95u
s  
long nFileLength; //文件长度 FuaGr0]  
boolean bFirst = true; //是否第一次取文件 :Ke~b_$Uy-  
boolean bStop = false; //停止标志 ^HKxaW9W  
File tmpFile; //文件下载的临时信息 uJG^>B?`b  
DataOutputStream output; //输出到文件的输出流 il-v>GJU7{  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +D1;_DU  
public SiteFileFetch(SiteInfoBean bean) throws IOException *#EyfMz-B  
{ tiwhG%?2  
siteInfoBean = bean; #hzs,tvvD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1K,bmb xRt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); NF0} eom  
if(tmpFile.exists ()) FFtj5e  
{ hGF:D#jyT  
bFirst = false; xYRL4  
read_nPos(); ~@R=]l"  
} x&)
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else f&^K>Jt1@#  
{ bM8b3,}?n  
nStartPos = new long[bean.getNSplitter()]; H"I|dK:  
nEndPos = new long[bean.getNSplitter()]; g<KBsz!{  
} b
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} Yk<?HNf  
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public void run() "S#0QH%5  
{ if:2sS9r  
//获得文件长度 WABq6q!  
//分割文件 "v jFL9  
//实例FileSplitterFetch _V6;`{$WK  
//启动FileSplitterFetch线程 V
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//等待子线程返回 |??uVA)\X  
try{ R$(,~~MH  
if(bFirst) :(A]Bm3  
{ 7Y@&&  
nFileLength = getFileSize(); sEe^:aSN  
if(nFileLength == -1) 2}I1z_dq~  
{ v8 ggPI  
System.err.println("File Length is not known!"); /$WEO[o  
} A#2Fd7&  
else if(nFileLength == -2) K-k;`s#  
{ 6/s#'#jh  
System.err.println("File is not access!"); tQz-tQg  
} Sxjwq
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else (Pc:A!}  
{ }#'O b  
for(int i=0;i<nStartPos.length;i++) Q>JJI:uC4  
{ 6BLw 4m=h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fX#Em'Ab[  
} #Cvjv; QwY  
for(int i=0;i<nEndPos.length-1;i++) q%Obrk  
{ *8,]fBUq  
nEndPos = nStartPos[i+1]; 8>6+]]O  
} d1``}naNw  
nEndPos[nEndPos.length-1] = nFileLength;  yYp!s
 
} *hAq]VC})  
} vDv:3qN7(  
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sR+=<u1  
//启动子线程 t_x\&+W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j5G8IP_Wx  
for(int i=0;i<nStartPos.length;i++) -fT]}T6=  
{ >q[(UV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vv"_u=H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b,]hX  
nStartPos,nEndPos,i); !d&K,k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yFH)PQ_  
fileSplitterFetch.start(); |.)oV;9  
} #fRhG^QKp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sD_Z`1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &^{HD }/{b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
=UM30 P/  
nEndPos = " + nFileLength); 5|9,S  
// fileSplitterFetch[nPos.length-1].start(); l~!\<, !  
M`9qo8zCi  
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//等待子线程结束 @vCPX=c  
//int count = 0; T7'njaLec  
//是否结束while循环 m@u!frE,  
boolean breakWhile = false; fJH09:@^%  
6 GO7[?U<  
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while(!bStop) k>FMy#N|@  
{ *[wy- fu  
write_nPos(); l|/h4BJ'  
Utility.sleep(500); &<_*yl p  
breakWhile = true; SWNi@  
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for(int i=0;i<nStartPos.length;i++) 1j`-lD  
{ [V|,O'X ~  
if(!fileSplitterFetch.bDownOver) cuO(*%Is1  
{ j#f+0  
breakWhile = false; +?w 7Nm`  
break; m.iCGX  
} d(3F:dbk  
} me_DONW  
if(breakWhile) w9rwuk  
break; D^baXp8  
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9%S{fd\#  
//count++; WS/^WxRY  
//if(count>4) GpMKOjVm|  
// siteStop(); 9c1g,:8\  
} IL 'i7p  
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System.err.println("文件下载结束！"); HJhPd#xCW  
} peCmb)>Sa  
catch(Exception e){e.printStackTrace ();}  9f+|m9~2  
} EgOAEv  
MqGF~h|+  
q#:,6HDd  
//获得文件长度 r(y1^S9!8  
public long getFileSize() 'YIFHn$!  
{ D9zw' RY  
int nFileLength = -1; dIQ7u  
try{ 9uV/G7Geq  
URL url = new URL(siteInfoBean.getSSiteURL()); ]sjYxe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q/m))!ikMt  
httpConnection.setRequestProperty("User-Agent","NetFox"); BIEc4k5(  
3UU]w`At  
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int responseCode=httpConnection.getResponseCode(); IMIZ
#/  
if(responseCode>=400) S(9Xbw)T  
{ ;ZHKTOoK  
processErrorCode(responseCode); h#'(i<5v  
return -2; //-2 represent access is error 5!$m3j_,]?  
} ,Xs%Cg_Ig  
A
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String sHeader; !8yw!hA  
+M
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for(int i=1;;i++) ^"7tfo8  
{ >8_#L2@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5JW+&XA  
//Utility.log(in.readLine()); sP$bp Z}  
sHeader=httpConnection.getHeaderFieldKey(i); ["- pylhK  
if(sHeader!=null)
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{ A"x1MjuqLM  
if(sHeader.equals("Content-Length")) ZZOBMF7  
{ @P#uH5U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oJe9H<  
break; g <^Y^~+E  
} yn<H^c  
} \?c0XD  
else JYL/p9K[I  
break; Oe4 l` =2  
} Y$b4Ga9j  
} UZ0fw@RM  
catch(IOException e){e.printStackTrace ();} ez=$]cln  
catch(Exception e){e.printStackTrace ();} Yr5A,-s  
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Utility.log(nFileLength); i<(Xr  
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return nFileLength; 5y?-fT]X  
} [b$4Shx  
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{8I.`U  
//保存下载信息（文件指针位置） n6k9~"?  
private void write_nPos() oP4GEr  
{ 1nu^F,M  
try{ TXZv2P9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )Jv[xY~  
output.writeInt(nStartPos.length); |c`w'W?C6  
for(int i=0;i<nStartPos.length;i++) ?:Bv iF);/  
{ yZ!T8"mz{  
// output.writeLong(nPos); K!KMQ
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output.writeLong(fileSplitterFetch.nStartPos); 7h)iu9j  
output.writeLong(fileSplitterFetch.nEndPos); bz| D-.  
} b pv=%  
output.close(); "HXYNS>  
} VAXT{s&4>  
catch(IOException e){e.printStackTrace ();} pn*3\  
catch(Exception e){e.printStackTrace ();} <`0h|m'U  
} l (3bW1{n  
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//读取保存的下载信息（文件指针位置） 8?FbtBAn  
private void read_nPos() ?^j^K-rx  
{ tbO H#|  
try{ rL5z]RY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); LF0sH)e]  
int nCount = input.readInt(); 6b!F1
  
nStartPos = new long[nCount]; d9n?v)<v  
nEndPos = new long[nCount]; f}D1|\7  
for(int i=0;i<nStartPos.length;i++) 5 Qoew9rA  
{ ?,yj")+  
nStartPos = input.readLong(); boo }u  
nEndPos = input.readLong(); 21(p|`X  
} `|Or{ih  
input.close(); e]Zngt?b  
} *kIc9}  
catch(IOException e){e.printStackTrace ();} t&9A ]<n%,  
catch(Exception e){e.printStackTrace ();} A 8 vbQ  
} >s`J5I!  
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private void processErrorCode(int nErrorCode) ujJI 1I  
{ G/v/+oX  
System.err.println("Error Code : " + nErrorCode); Pm$q]A~  
} YSaJeU>@  
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[  
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//停止文件下载 R=Tqj,6  
public void siteStop() [ 4;Ii  
{ H}LS??P  
bStop = true; I=;+n-  
for(int i=0;i<nStartPos.length;i++) wKH ::!  
fileSplitterFetch.splitterStop(); .IJ_jt-^d  
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)}  
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} oBUxKisW  
} V)P&Zw  
//负责部分文件的抓取 .%zy`n  
**FileSplitterFetch.java F,5r9^,_  
*/ #oJ5k8Wy  
package NetFox; F:#J:x'  
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import java.io.*; + S4fGT  
import java.net.*; *H[Iq!@  
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public class FileSplitterFetch extends Thread { ,&4qgp{)  
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dt  
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String sURL; //File URL {m`A!qcD|  
long nStartPos; //File Snippet Start Position MV=9!{`  
long nEndPos; //File Snippet End Position L^^4=ao0  
int nThreadID; //Thread's ID gDIBnH  
boolean bDownOver = false; //Downing is over tb?YLxMV  
boolean bStop = false; //Stop identical S^Au#1e   
FileAccessI fileAccessI = null; //File Access interface nv<` K9d  
4'p=p#o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {J5JYdK  
{ _owjTo}  
this.sURL = sURL; D=TL>T.bf  
this.nStartPos = nStart; +u'I0>)S  
this.nEndPos = nEnd; an2AX%u  
nThreadID = id; d4% `e&K]'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 b h*^
{  
} JxnuGkE0[#  
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public void run() y&y/cML?  
{ T0YDfo  
while(nStartPos < nEndPos && !bStop) "bPCOJ[v9  
{ 5St`@  
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try{ Ri;=aZ5m  
URL url = new URL(sURL); epn#qeX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FOc|*>aKP  
httpConnection.setRequestProperty("User-Agent","NetFox"); |PI)A`  
String sProperty = "bytes="+nStartPos+"-"; (=`Z0)=  
httpConnection.setRequestProperty("RANGE",sProperty); Sf=F cb  
Utility.log(sProperty);  oHOW5  
6g}^Q?cpV#  
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InputStream input = httpConnection.getInputStream(); Q,D0kS P  
//logResponseHead(httpConnection); ]7v81G5E  
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byte[] b = new byte[1024]; xLe =d|6  
int nRead; Ir!2^:]!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4 #aqz9k  
{ {d^Q7A:`  
nStartPos += fileAccessI.write(b,0,nRead); K2*1T+?X  
//if(nThreadID == 1) /%62X{=>
;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CdDH1[J  
} 3\7'm]  
"!xvpsy  
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Utility.log("Thread " + nThreadID + " is over!"); ]}p2Tp;1  
bDownOver = true; a_Z.J
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//nPos = fileAccessI.write (b,0,nRead); anK[P'Y  
} cT_uJbP+  
catch(Exception e){e.printStackTrace ();} m~##q}LZ  
} 03~+-h&n  
} >sn"  
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//打印回应的头信息 c
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public void logResponseHead(HttpURLConnection con) FTbT9   
{ ^Vl^,@  
for(int i=1;;i++) A,3@j@bdy  
{ yQ<6p3  
String header=con.getHeaderFieldKey(i); B1x'5S;Bq  
if(header!=null) sVE>=0TVP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <+<)xwOQ ]  
Utility.log(header+" : "+con.getHeaderField(header)); ny278tr Q7  
else Lv  
break; PXOrOK  
} -;sJ25(  
} 3js)niT9u  
g@$0FY{Q  
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public void splitterStop() +`Q PBj^  
{ 4aj[5fhb-  
bStop = true; j'G"ZPw1  
} 9c"0~7v  
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} zb@L)%  
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.}  
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/* y&n1 Nj]^  
**FileAccess.java 3c1o,2  
*//文件访问(定位，写) #gxRTx  
package NetFox; F7k4C2r  
import java.io.*; $-C6pZN(X  
?9o#%?6k  
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public class FileAccessI implements Serializable{ 5A0KV7N5  
==jkp U*=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t:?<0yfp&  
RandomAccessFile oSavedFile; v&t`5-e-A  
long nPos; '0\0SL   
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public FileAccessI() throws IOException Z&~k]R0y  
{ o'x_g^ Y  
this("",0); EGQ1li'B  
} !nP8ysB  
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public FileAccessI(String sName,long nPos) throws IOException ~N
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{ sqq/b9 uL/  
oSavedFile = new RandomAccessFile(sName,"rw"); /ieu)m:2  
this.nPos = nPos; ~Mg8C9B?%3  
oSavedFile.seek(nPos); u
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} fzGZ:L  
dK=D=5r,  
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public synchronized int write(byte[] b,int nStart,int nLen) BDB zc5Q(  
{ a$+e8>  
int n = -1; %k1q4qOG]^  
try{ .@x"JI>;  
oSavedFile.write(b,nStart,nLen); Ggxrj'r  
n = nLen; ey9fbS ^I  
} e>)}_b  
catch(IOException e) R'1vjDuv  
{ H|(*$!~e  
e.printStackTrace (); I'6ed`|  
} kBDe*K.V  
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return n; \fQgiX  
} eog,EP"a8Y  
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} ><Mbea=U+  
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/* !O%f)v?  
**SiteInfoBean.java JzS^9)&  
*/ (cqA^.Td  
package NetFox; H$($l<G9C  
\`<s@U  
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$  
public class SiteInfoBean { N;Gf,pE  
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jAQ)3ON<  
private String sSiteURL; //Site's URL iM-hWhU  
private String sFilePath; //Saved File's Path {(zL"g46  
private String sFileName; //Saved File's Name wxr}*Z:ZMa  
private int nSplitter; //Count of Splited Downloading File -%QEzu&  
oVj A$|  
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public SiteInfoBean() \2LA%ZU  
{//nSplitter的缺省值为5 X|QX1dl  
//default value of nSplitter is 5 ?_h#>  
this("","","",5); tX2>a  
} U:\oGa84A  
& /FA>  
!C)>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^SL}wC x  
{ 
]V[  
sSiteURL= sURL; (^OC%
pc  
sFilePath = sPath; B2+_F"<;  
sFileName = sName; -B++V  
this.nSplitter = nSpiltter; E4fvYV_ra  
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} AXv3jH,HF  
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,-  

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public String getSSiteURL() $F'~^2  
{ .dq.F#2B;  
return sSiteURL; UqQZ A0e  
} orN2(:Ct7  
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&I">{J<  
public void setSSiteURL(String value) _:z
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{ Z-r0 D  
sSiteURL = value; 0~I) /T  
} gQzF C&g  
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6(;[ov1  
public String getSFilePath() P_}_D{G  
{ X=RmCc$:  
return sFilePath; tbt9V2U:"n  
} P6Ol+SI#m  
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public void setSFilePath(String value) @!tmUme1c  
{ H "/e%  
sFilePath = value; { l~T~3/i  
} ry=[:\Z~  
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@o.i2iG  
public String getSFileName() ':fbf7EL<  
{ KuAGy*:4T  
return sFileName; 8&AorYw[  
} zL=I-fVq  
H0:6zSsc=|  
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public void setSFileName(String value) W8/6  
{ CHSD8D  
sFileName = value; y")>"8H  
} [
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%Y[/Ucdm  
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public int getNSplitter() *8HxJ+[,[  
{ sm <kb@g  
return nSplitter; 3m9E2R,  
} zTzG&B-  
MA QY/s~F  
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public void setNSplitter(int nCount) 0To 5|r  
{ v2<gkCK^  
nSplitter = nCount; X'p%$HsMG  
} l"g%vS,;`  
} =hb87g.  
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>}tG^)os  
/* -igZU>0B_  
**Utility.java MH(g<4>*  
*/ rkXSygb  
package NetFox; :jCaDhK  
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rI$10R$+H  
public class Utility { y$W3\`2q  
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public Utility() 1EzA@3:{  
{ :36^^Wm  
&?pAt30K:  
7t/SZm  
} wN.Jyb  
LZ$!=vg4  
//线程睡眠 WJ,ON-v  
public static void sleep(int nSecond) $9$NX/P  
{ _3JTHf<+  
try{ AX?6Q4Gq1  
Thread.sleep(nSecond); yFv3>\  
} *GnO&&m'B  
catch(Exception e) WVFy ZpB  
{ G(e?]{(  
e.printStackTrace (); e70*y'1fu  
} /zAx`H  
} [Y+
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J]e&z5c  
//日志 B 8,{jwB  
public static void log(String sMsg) m\Nc}P_"p  
{ rZ7 Ihof  
System.err.println(sMsg); 3Q;l*xu  
} zc5_;!t  
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y+<HS]vyV  
public static void log(int sMsg) C5?M/xj  
{ Qmn5-yiw1d  
System.err.println(sMsg); sIe(;%[`  
} DO; 2)ZQ%  
} W@Wh@eSb;  
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[)?3Dp|MH  
/* R8)"M(u=l  
**TestMethod.java 9IMcp~zX  
*/ mB`r6'#=  
package NetFox; FB`HwE<  
A>k;o0r  
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public class TestMethod { VdgPb (  
R _%pR_\  
/zM7G
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public TestMethod() h9mR+ng*oD  
{ ///xx/weblogic60b2_win.exe 6fiJ' j@  
try{ dLq!t@?iu>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t+tGN\q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z:{Z&HQC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ub&1L_K  
fileFetch.start(); Y|L57F  
} `N0E;=g  
catch(Exception e){e.printStackTrace ();} /uWON4  
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} KK}&4^q  
~F-,Q_|-  
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public static void main(String[] args) C/JFg-r  
{ *MNY1+RJ  
new TestMethod(); >8##~ZuF+
 
} ME.LS2'n  
} ,3K?=e2  
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