http断点续传简单实现（java)

/* Ahd\TH  
**SiteFileFetch.java q1<Fg.-r  
*/ o>$|SU!a  
package NetFox; 8q{1E];:q  
import java.io.*; -Cml0}.O  
import java.net.*; V[To,f  
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public class SiteFileFetch extends Thread { ax;{MfsK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &KOO
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long[] nStartPos; //开始位置 `L+~&M  
long[] nEndPos; //结束位置 y 2cL2c$BT  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xan/ay>  
long nFileLength; //文件长度 1wU=WE(kKZ  
boolean bFirst = true; //是否第一次取文件 Q;Q  
boolean bStop = false; //停止标志 3[iSF5%V*p  
File tmpFile; //文件下载的临时信息 ^,~N7`  
DataOutputStream output; //输出到文件的输出流 `6n!$Cxo  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <XY;fhnB  
public SiteFileFetch(SiteInfoBean bean) throws IOException %
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{ T&mbXMN  
siteInfoBean = bean;
+i_'gDy$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T^+1rG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q!9^#c  
if(tmpFile.exists ()) h<Jc;ht  
{ tu7+LwF7  
bFirst = false; =]WW'~  
read_nPos(); @
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} QR|XV%$  
else A4}JZi6@  
{ p"g1V7B  
nStartPos = new long[bean.getNSplitter()]; CL EpB2_  
nEndPos = new long[bean.getNSplitter()]; )#)
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} JgxE|#*7U  
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} Zm`'MsgFr  
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public void run() 9*7Hoi4Ji  
{ j{-mQTSD  
//获得文件长度 **Qe`}E:  
//分割文件 wBg<Q{J  
//实例FileSplitterFetch Xs{:[vRW  
//启动FileSplitterFetch线程 =W;
t@"6>2  
//等待子线程返回 m]{<Ux  
try{ )RpqZe/h4  
if(bFirst) oqm  
{ v@F|O8t:s  
nFileLength = getFileSize(); E_ o{c5N  
if(nFileLength == -1) J
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{ Qx9>,e6+  
System.err.println("File Length is not known!"); E`A<]dAoK  
} L"Qh_+  
else if(nFileLength == -2) i5ajM,i/K  
{ P@^z:RS*{  
System.err.println("File is not access!"); ~uP r]#  
} ~ >&I^4  
else E.
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{ :;" aUHU'  
for(int i=0;i<nStartPos.length;i++) Ib_n'$5#z  
{ j;1~=j])  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); []GthF  
} Xtu:  
for(int i=0;i<nEndPos.length-1;i++) _)HD4,`  
{ ws*~$x?7  
nEndPos = nStartPos[i+1]; Vy?R/ Uu  
} ccHLL6F{  
nEndPos[nEndPos.length-1] = nFileLength; H1aV}KD  
} {
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} 2LhfXBWf  
pDLu+}@  
&:!ZT=  
//启动子线程 gaLEhf^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V6DBKq  
for(int i=0;i<nStartPos.length;i++) XgwMppacw  
{ [u`17hyX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o2[vM$]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .g6PrhzFbk  
nStartPos,nEndPos,i); 2eZk3_w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PfwI@%2  
fileSplitterFetch.start(); $V`KrA~]  
} &=+cov(3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M<SbVP|V"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); el2*\(XT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k"Z"$V2i  
nEndPos = " + nFileLength); @%I_&!d  
// fileSplitterFetch[nPos.length-1].start(); >?\v@  
$UFge%`,q@  
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//等待子线程结束 = )JVT$]w  
//int count = 0; yr/]xc$  
//是否结束while循环 vp )}/&/  
boolean breakWhile = false; O<eWq]  
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while(!bStop) Zq\RNZ}  
{ :_{{PY0PK  
write_nPos(); j#Ky0+@V  
Utility.sleep(500); z*NC?\  
breakWhile = true; SIaUrC  
'[M^f+H|  
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for(int i=0;i<nStartPos.length;i++) w(vE2Y ?  
{ ,w9#%=xE  
if(!fileSplitterFetch.bDownOver) YJ$Vn>6Z  
{ +WU|sAK"  
breakWhile = false; IF36K^K  
break; `uM0,Z

  
} B"?+5A7  
} !i~x"1  
if(breakWhile) }rj C_q  
break; #x4h_K Y  
@dWS*@  
/P?|4D}<  
//count++; tpNtoqg_$  
//if(count>4) &.+n L  
// siteStop(); !yV,|)y5F  
} Th&Wq  
Y^94iOk%T  
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System.err.println("文件下载结束！"); }ZM*[j  
} EL 8N[]RF  
catch(Exception e){e.printStackTrace ();} `\RX~ $^  
} nyl8=F:V  
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//获得文件长度 &0th1-OP_  
public long getFileSize() 4mM2C`I  
{  s>*Q  
int nFileLength = -1; c5wkzY h  
try{ "&~?Hzm  
URL url = new URL(siteInfoBean.getSSiteURL()); 5Sm5jRr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iXG>j.w{79  
httpConnection.setRequestProperty("User-Agent","NetFox"); B:6sVJ  
I
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int responseCode=httpConnection.getResponseCode(); *1o+o$hY2  
if(responseCode>=400) quCWc2pXX  
{ >^a"Z[s[  
processErrorCode(responseCode); wEHAkc
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return -2; //-2 represent access is error UgD'Bi  
} JK:mQ_  
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q
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String sHeader; lEYT{  
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for(int i=1;;i++) <*r<+S   
{ }n2-*{)x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aaqd:N)  
//Utility.log(in.readLine()); |W~V@n8"6  
sHeader=httpConnection.getHeaderFieldKey(i); QGbD=c7  
if(sHeader!=null) f,`}hFD  
{ bWQORjnd8  
if(sHeader.equals("Content-Length")) '4^V4i  
{ _;J9q}X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a7v[l04  
break; ]\D6;E8P-~  
} QS=$#Gp  
} @aiLGwh  
else rs 1*H  
break; [K)1!KK,L  
} R26tQbwE  
} ,@'){V
 
catch(IOException e){e.printStackTrace ();} LD~uI  
catch(Exception e){e.printStackTrace ();} QIMv9;  
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Utility.log(nFileLength); FbCZV3Y  
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return nFileLength; @DQ"vFj6<  
} !k>H e*M}P  
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//保存下载信息（文件指针位置） MVeQ5c(  
private void write_nPos() 9+is?Pj  
{ ndCS<ojcBP  
try{ tzW<&^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iQ]c k-  
output.writeInt(nStartPos.length); v20
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for(int i=0;i<nStartPos.length;i++) 't]EkH]BC  
{ da?th  
// output.writeLong(nPos); !^w\$cw&  
output.writeLong(fileSplitterFetch.nStartPos); 18/
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output.writeLong(fileSplitterFetch.nEndPos); M(h H#_$  
} \2<yZCn  
output.close(); mN'9|`>V>  
} n8O
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catch(IOException e){e.printStackTrace ();} w)m0Z4*  
catch(Exception e){e.printStackTrace ();} 9-E>n)  
} 55\X\> 0C7  
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\  
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//读取保存的下载信息（文件指针位置） GY$?^&OO>  
private void read_nPos() 'y M:WcN  
{ ^Lfn3.M  
try{ ;~Gpw/]5E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); CU>K  
int nCount = input.readInt(); U)w|GrxX  
nStartPos = new long[nCount]; >'|xQjLl  
nEndPos = new long[nCount]; /L|}Y242  
for(int i=0;i<nStartPos.length;i++) <9@]|  
{ 5WNg+  
nStartPos = input.readLong(); vBn=bb'W  
nEndPos = input.readLong(); SQKY;p  
} &G,o guo  
input.close(); 6% y)  
} / ?[gB:s  
catch(IOException e){e.printStackTrace ();} wCTR-pL^  
catch(Exception e){e.printStackTrace ();} ^)IL<S&h  
} ;?lM|kK  
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9MzkG87J  
private void processErrorCode(int nErrorCode) POg0=32  
{ 5 EuJ  
System.err.println("Error Code : " + nErrorCode); PKM$*_LcGI  
} pnA]@FW  
WmVw>.]@~  
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//停止文件下载 0l1]QD+Gc5  
public void siteStop() ,WDAcQ8\  
{ muX4Y1M_  
bStop = true; 
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for(int i=0;i<nStartPos.length;i++) :kx#];2i  
fileSplitterFetch.splitterStop(); 4b(irDT3F  
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} Okg8Ve2  
} =]xk-MY"|R  
//负责部分文件的抓取 VUv.Tx]Z[  
**FileSplitterFetch.java Sw( H]  
*/ Rw{v"n  
package NetFox;  ~M^7qO  
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import java.io.*; u[|S*(P  
import java.net.*; z%dlajYm:  
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public class FileSplitterFetch extends Thread { |ShRxE3@'  
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String sURL; //File URL {uM{5GSL  
long nStartPos; //File Snippet Start Position ;_\  
long nEndPos; //File Snippet End Position pbvEIa-Y4  
int nThreadID; //Thread's ID %+!9  
boolean bDownOver = false; //Downing is over e&4wwP"`<  
boolean bStop = false; //Stop identical IIn\{*|mW  
FileAccessI fileAccessI = null; //File Access interface x15t
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _vLT!y  
{ WI!z92qq[  
this.sURL = sURL; 4$2
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this.nStartPos = nStart; !cq|g  
this.nEndPos = nEnd; Tc(v\|F,  
nThreadID = id; M)pi)$&c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BBJ]>lQ  
} :::f,aCAu  
+\oHQ=s>}\  
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public void run() uv!qE1z@':  
{ ~S>ba']  
while(nStartPos < nEndPos && !bStop) .*f4e3  
{ #R PB;#{  
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try{ y8S6ZtA}2  
URL url = new URL(sURL); &&S4x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eRy'N|'  
httpConnection.setRequestProperty("User-Agent","NetFox"); GWZXRUc  
String sProperty = "bytes="+nStartPos+"-"; ^k<$N  
httpConnection.setRequestProperty("RANGE",sProperty); RWQW/Gwx  
Utility.log(sProperty);  Q<ExfJm  
QGj5\{E_  
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InputStream input = httpConnection.getInputStream(); 5nq-b@?L  
//logResponseHead(httpConnection); P1>X5:  
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byte[] b = new byte[1024]; }t-|^mY>  
int nRead; 3}1+"? s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qTMz6D!Q  
{ ujqktrhuLb  
nStartPos += fileAccessI.write(b,0,nRead); p% %Y^=z  
//if(nThreadID == 1) Qu\l$/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 64X#:t+  
} c
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3A}8
?  
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Utility.log("Thread " + nThreadID + " is over!"); FN`kSTm*0!  
bDownOver = true; 1CVaGD^r{  
//nPos = fileAccessI.write (b,0,nRead); r3vj o(  
} =F[,-B~  
catch(Exception e){e.printStackTrace ();} 2=M!lB *  
} hD"~ ^  
} SZD2'UaG  
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//打印回应的头信息 [te7uZv-  
public void logResponseHead(HttpURLConnection con) 5g2+Ar(  
{ ]LOtwY  
for(int i=1;;i++) }jgAV  
{ aKtTx~$@  
String header=con.getHeaderFieldKey(i); p&l:937  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); B9:0|i!!A`  
Utility.log(header+" : "+con.getHeaderField(header)); |?=1tS{iT  
else
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break; K3D $ hb  
} '+zsj0!A  
} Jz0S2&  
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public void splitterStop() P`"DepeD  
{ .WE0T|qDX  
bStop = true; 'B6H/d
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} bQjHQ"
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} 1&"1pH  
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/* @cGql=
t  
**FileAccess.java bM3e7olWS  
*//文件访问(定位，写) AR3=G>hO,  
package NetFox; L"/ato  
import java.io.*; D9C; JD  
^D[;JV  
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public class FileAccessI implements Serializable{ ".<p R} qp  
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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 rP4@K%F9jB  
RandomAccessFile oSavedFile; 9ksrr{tW  
long nPos; lM,:c.R  
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public FileAccessI() throws IOException ;f~'7RKy!G  
{ %TgM-F,8  
this("",0); iW~f  
} vy?YA-  
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public FileAccessI(String sName,long nPos) throws IOException Y|nTc.A  
{ Mv=;+?z!  
oSavedFile = new RandomAccessFile(sName,"rw"); \s'6)_  
this.nPos = nPos; ?0Zw ^a  
oSavedFile.seek(nPos); _0E,@[  
} Bx>@HU
 
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public synchronized int write(byte[] b,int nStart,int nLen) R&xd ic!  
{ gXMkI$ab  
int n = -1; [?*^&[  
try{ mJ7kOQ-.$  
oSavedFile.write(b,nStart,nLen); c= uORt>  
n = nLen; mH .I!  
} Y,~]ecI  
catch(IOException e) <~w#sIh  
{ MsQS{ok+  
e.printStackTrace (); LJ3UB  
} DI[Ee?  
9t1_"{'N1  
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return n; Qpq0j^\  
} (tN$G:+")F  
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#
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} yl%F<5  
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/* th,qq  
**SiteInfoBean.java ^5}3FvW  
*/ pE N`&'4  
package NetFox; H(s^le:!  
o+&sodt|`  
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public class SiteInfoBean { b87o6"j  
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private String sSiteURL; //Site's URL s2WB4Uk  
private String sFilePath; //Saved File's Path ps{(UYM=b  
private String sFileName; //Saved File's Name p?@
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private int nSplitter; //Count of Splited Downloading File GkFNLM5'  
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public SiteInfoBean() is$d<Y&F  
{//nSplitter的缺省值为5 E?uv&evPK7  
//default value of nSplitter is 5 CjGI}t  
this("","","",5); A )cb
 
} HZ3<}`P_W  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R?Qou!*
]  
{ Kw|`y %~  
sSiteURL= sURL; }s[/b"%y  
sFilePath = sPath; ]\U'_G2]  
sFileName = sName; \Wk$>?+#@  
this.nSplitter = nSpiltter; JV>OmUAk  
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(x@"Dp=MZW  
} =[&Jxy>Y  
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public String getSSiteURL() XEI]T~  
{ ( 9l|^w["  
return sSiteURL; K]l)z* I  
} plq\D.C  
T5h[{J^  
=Sq7U^(>  
public void setSSiteURL(String value) y8@!2O4  
{ sBwgl9  
sSiteURL = value; Ih0GzyU*4  
}  ^8iy(  
AXCJFqk;  
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public String getSFilePath() vY6
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{ xjpW<-)MLf  
return sFilePath; EbQ}w"{  
} *
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public void setSFilePath(String value) LFC k
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{ >+r2I%  
sFilePath = value; vhC"f*  
} tdm /U  
VbjFQ@[l!  
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public String getSFileName() Z6p>R;9n  
{ fu/c)D6u*m  
return sFileName; w#XJ!f6*_9  
} XV&3h>5  
cW RY[{v  
&}r932  
public void setSFileName(String value) KB^IGF  
{ 5eYCnc9  
sFileName = value; 1^COR+>L  
} ?=l(29tH  
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B06/mKZ7  
public int getNSplitter() y}VKFRky  
{ iq#Z\Y(  
return nSplitter; Z&%61jGK  
} 3-05y!vbcE  
+vP1DXtj(  
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public void setNSplitter(int nCount) d={}a,3?  
{ 7"NUof?i  
nSplitter = nCount; 7j Q`i;L}Y  
} e|I5Nx2)  
} ,RZktWW_  
}Y[.h=X  
6=
 
/* Q|>y2g!  
**Utility.java D"MNlm  
*/ =k'dbcfO$9  
package NetFox; mXr)lA  
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public class Utility { 'BC-'Ot  
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public Utility() ?}y7S]B FI  
{ Ul=`]@]]  
| 8AH_Fk  
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} p7*\]HyE)  
&"BKue~q@p  
//线程睡眠 R1nctA:  
public static void sleep(int nSecond) 8wBns)wy@  
{ |^1eL I  
try{ jkbz8.K  
Thread.sleep(nSecond); yoH6g?!O  
} 4avM:h  
catch(Exception e) j_}e%
,}  
{ eRGip2^cq+  
e.printStackTrace (); cX*^PSM  
} T:si?7CR  
} ':Te#S  
' o5,P/6  
//日志 !} 1p:@  
public static void log(String sMsg) M! s&<Bi  
{ lY~xoHT;[  
System.err.println(sMsg); I=1tf;Bsi  
} AOTI&v  
Ei#"r\q j_  
m,pDjf  
public static void log(int sMsg) $o
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{ !v^D j']  
System.err.println(sMsg); K1Tzy=Z9j  
} x*YJ:t  
} =$HzEzrw  
W4N$]D=  
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/* '{J!5x?L^  
**TestMethod.java #hai3>9|B  
*/ ?znSA >  
package NetFox; AVi|JY)>  
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r6^DD$X  
public class TestMethod { ]Z~H9!%t  
`0sa94H1[  
IlwY5iL  
public TestMethod() 4Q$\hO3b  
{ ///xx/weblogic60b2_win.exe F Hv|6zUX  
try{ `T-(g1:9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @A)gsDt9A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /_LUys/0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7c+u+Yet  
fileFetch.start(); %3q@\:s  
} 0s4%22  
catch(Exception e){e.printStackTrace ();} tUtl>>6Iu  
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b2Ct^`|M5  
} kcQ |Z
g  
Jl}$)'  
}ulFW]A^7  
public static void main(String[] args) =Y89X6  
{ Jk`A}  
new TestMethod(); 5H<rI?  
} N^)L@6  
} r|&qXb x  
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