http断点续传简单实现（java)

/* z
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**SiteFileFetch.java 2C8M1^0:Z  
*/ $K G?d>wx  
package NetFox; zR<jZwo]#  
import java.io.*; :e9E#o
 
import java.net.*; oL6_Ya  
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public class SiteFileFetch extends Thread { nEn2!)$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean FP\[7?ZLn  
long[] nStartPos; //开始位置 _88~uYG  
long[] nEndPos; //结束位置 `H|g~7KD&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @LmUCP~  
long nFileLength; //文件长度 QTyl=z7  
boolean bFirst = true; //是否第一次取文件 PHOW,8)dZh  
boolean bStop = false; //停止标志 WMC6dD_6e  
File tmpFile; //文件下载的临时信息 4v?S`w:6  
DataOutputStream output; //输出到文件的输出流 !kz\ {  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [j/-(?+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~gAx  
{ 5s|g
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siteInfoBean = bean; Cv=
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lubS{3<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bBQp:P?E  
if(tmpFile.exists ()) w5nRgdboy!  
{ GS^4tmc  
bFirst = false; d8K^`k+x  
read_nPos();  )Ob{]  
} p*'?(o:=  
else "h#=ctCx"  
{ ]Lh\[@#1f  
nStartPos = new long[bean.getNSplitter()]; &,)tD62s  
nEndPos = new long[bean.getNSplitter()]; D *tBbV  
} 5u!
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} =wQ=`  
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public void run() _96&P7  
{
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//获得文件长度 dvf*w:5K!  
//分割文件 (+@.L7>m+t  
//实例FileSplitterFetch BKTsc/v2>:  
//启动FileSplitterFetch线程 Psv!`K  
//等待子线程返回 xWMMHIu  
try{ kDKpuA!  
if(bFirst) *SW,pHYnLb  
{ I@B7uFj  
nFileLength = getFileSize(); ,)RdXgCs  
if(nFileLength == -1) ibq@0CR  
{ AjS5  
System.err.println("File Length is not known!"); C+mU_g>  
} JB|I/\(A  
else if(nFileLength == -2) : ?V;  
{ y\[=#g1(@  
System.err.println("File is not access!"); }B5I#Af7  
} PX'LN  
else Dz{e@+>M  
{ a !IH-XJ2  
for(int i=0;i<nStartPos.length;i++) ZUu^==a  
{ W< n`[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2*|]#W
 
} i_MI!o  
for(int i=0;i<nEndPos.length-1;i++) \x!>5Z Y  
{ LWI~m2  
nEndPos = nStartPos[i+1]; @FTi*$Ix  
} D)_Ei'+*l  
nEndPos[nEndPos.length-1] = nFileLength; dd$N4&  
} V~=)#3]`[  
} y AWDk0bx  
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//启动子线程 =%3nKSg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _=8+_OEk  
for(int i=0;i<nStartPos.length;i++) T)uw2  
{ ]ok>PH]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c;^J!e  
nStartPos,nEndPos,i); ^Toi_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R+K[/AA  
fileSplitterFetch.start(); #RF=a7&F  
} Trrh`@R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gy{a+Wbc*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <}%ir,8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B /W$RcV  
nEndPos = " + nFileLength); E(@;p%:  
// fileSplitterFetch[nPos.length-1].start(); +RkYW*|$S  
~laZ(Bma);  
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//等待子线程结束 `9ox?|iJ  
//int count = 0; )hug<D *h  
//是否结束while循环 #*!$!c{  
boolean breakWhile = false; :~(im
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while(!bStop) 5)UmA8"zVB  
{ CC\z_C*P-p  
write_nPos(); `y}
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Utility.sleep(500); q8Dwu3D  
breakWhile = true; i7rq;t<  
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for(int i=0;i<nStartPos.length;i++) ZkW@|v  
{ g1~I*!p  
if(!fileSplitterFetch.bDownOver) hptuTBD  
{ PlZiTP  
breakWhile = false; qedGBl&  
break; MbfzGYA2~  
} $T6Qg(p  
}  qR qy  
if(breakWhile) y
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break; (5~C _Y  
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//count++; 5-^%\?,x  
//if(count>4) 8-
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// siteStop(); ^%&x{F.  
} >A&@Wp1  
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System.err.println("文件下载结束！"); $VWzv4^:  
} 91H0mP>ki  
catch(Exception e){e.printStackTrace ();} l,.?-|Poa  
} h '[vB^  
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//获得文件长度 ~7pjk  
public long getFileSize() kA__*b}8UK  
{ sg{D
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int nFileLength = -1; :OCuxSc%5  
try{ U
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URL url = new URL(siteInfoBean.getSSiteURL()); 'c&@~O;^d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n*Vd<m;w  
httpConnection.setRequestProperty("User-Agent","NetFox"); +5[oY,^cO  
-kbm$~P  
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int responseCode=httpConnection.getResponseCode(); @@83PJFid  
if(responseCode>=400) pm]DxJ@  
{ .KucjRI  
processErrorCode(responseCode); Da[C'm=  
return -2; //-2 represent access is error N@6OQ:,[F  
} yvCR =C  
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String sHeader; toqzS!&.v  
| ",[C3Jg  
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for(int i=1;;i++) Rt^<xXX$  
{ p{q!jm~Nq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4q13xX  
//Utility.log(in.readLine()); U5!f++  
sHeader=httpConnection.getHeaderFieldKey(i); W@,p9=425  
if(sHeader!=null) 
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{ Reu{   
if(sHeader.equals("Content-Length")) *Ca)RgM  
{ 9
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lt6
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break; j yRSEk$  
} =nx:GT3&[  
} -'[(Uzj  
else [!@oRK
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break; :z.Y$]F@  
} *xg`Kwl5Kl  
} 9xn23*Fo  
catch(IOException e){e.printStackTrace ();} S tnv>  
catch(Exception e){e.printStackTrace ();} UVc<C 1q  

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}  
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Utility.log(nFileLength); s;2/Nc   
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return nFileLength; 12sD|j  
} V.ji _vX  
] 5v4^mk  
qmA2bw]  
//保存下载信息（文件指针位置） 'd#\7J>d  
private void write_nPos() ^mueFw}\  
{ ,LW+7yD  
try{ \c~{o+UD-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); knOnUU  
output.writeInt(nStartPos.length); s S5fd)x  
for(int i=0;i<nStartPos.length;i++) ydND$@; Z  
{ HNy/ -  
// output.writeLong(nPos); x8?x/xE  
output.writeLong(fileSplitterFetch.nStartPos); 5
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output.writeLong(fileSplitterFetch.nEndPos); {kPe#n>xT  
} pzq;vMr  
output.close(); {HHh.K  
} r1oku0o  
catch(IOException e){e.printStackTrace ();} $54=gRo^  
catch(Exception e){e.printStackTrace ();} <D!c ~*[  
} /3Nb  
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//读取保存的下载信息（文件指针位置） g[s\~MF@s  
private void read_nPos() 0UGiPH,()  
{ d)0LVa(  
try{ 1V
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); oY%"2PW1B  
int nCount = input.readInt(); X#DL/#z k  
nStartPos = new long[nCount]; ')5L_$  
nEndPos = new long[nCount]; wfDp,T3w7  
for(int i=0;i<nStartPos.length;i++) lMwk.#  
{ [.;%\>Qk<  
nStartPos = input.readLong(); YxEbg(Y  
nEndPos = input.readLong(); qA/#IUi)1  
} mT6q}``vtG  
input.close(); Fkcx+
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} Jf?S9r5Q  
catch(IOException e){e.printStackTrace ();} 5'X74`  
catch(Exception e){e.printStackTrace ();} K)/!&{7n}a  
} U.RW4df%E  
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private void processErrorCode(int nErrorCode) -4e)N*VVu  
{ g={]Mzh  
System.err.println("Error Code : " + nErrorCode); N&fW9s}  
} 1Sg|3T8bGT  
f4'El2>-86  
{jOzap|  
//停止文件下载 T+;H#&  
public void siteStop() K[uY+!'1  
{ ZU-4})7uSB  
bStop = true; 3J'73)y  
for(int i=0;i<nStartPos.length;i++) hIVI\U,  
fileSplitterFetch.splitterStop(); 3cOY0Z#T  
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} ;GE26Ymqly  
} Cs:+93w  
//负责部分文件的抓取 n .f4z<  
**FileSplitterFetch.java B;z;vrrL  
*/ O`i)?BC  
package NetFox; Y^R?Q'  
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import java.io.*; $A;7Em  
import java.net.*; 3s`V)aXP  
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public class FileSplitterFetch extends Thread { j?:`-\w5  
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String sURL; //File URL W/ g
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long nStartPos; //File Snippet Start Position /Jxq 3D)v  
long nEndPos; //File Snippet End Position m$fQ`XzU  
int nThreadID; //Thread's ID 9ZDVy7m\i-  
boolean bDownOver = false; //Downing is over FZe:co8Mu  
boolean bStop = false; //Stop identical *.,"N}  
FileAccessI fileAccessI = null; //File Access interface UrO=!
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #V.ZdLo(  
{ 3ty4D2y  
this.sURL = sURL; k"">2#V  
this.nStartPos = nStart; "7=
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this.nEndPos = nEnd; ;asm 0H(  
nThreadID = id; Mv
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 =X%!YZk p  
} 2E$^_YT C  
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public void run() U/ ?F:QD4  
{ QVIcb;&:}  
while(nStartPos < nEndPos && !bStop) +J|+es  
{
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try{ NW z9C=y  
URL url = new URL(sURL); L-#e?Y}$J
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (O$}(Tn  
httpConnection.setRequestProperty("User-Agent","NetFox"); D=$4/D:;  
String sProperty = "bytes="+nStartPos+"-"; }@d>,1DU  
httpConnection.setRequestProperty("RANGE",sProperty); zhNQuK,L  
Utility.log(sProperty); ?-e7e%  
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}N?g|  
InputStream input = httpConnection.getInputStream(); wHx}U M"  
//logResponseHead(httpConnection); :^n*V6.4  
'X9AG6K1  
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byte[] b = new byte[1024]; 6N"m?g*Z d  
int nRead; rwy+~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H4t)+(:D'  
{ Zr=ib  
nStartPos += fileAccessI.write(b,0,nRead); d$pYo)8o({  
//if(nThreadID == 1) ^f9>l;Lb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8qn 9|  
} OY:u',T  
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Utility.log("Thread " + nThreadID + " is over!"); 0; 7#ji  
bDownOver = true; Z a! gbt  
//nPos = fileAccessI.write (b,0,nRead); `19qq]  
} U_]=E<el  
catch(Exception e){e.printStackTrace ();} B`i$Wt<7  
} j_p
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} !x>,N%~  
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//打印回应的头信息 :$Q`>k7A  
public void logResponseHead(HttpURLConnection con) 1Pm4.C)  
{ V\0E=M*P  
for(int i=1;;i++) .46#`4av  
{ CphFv!k'Z  
String header=con.getHeaderFieldKey(i); }`9jH:q-Z  
if(header!=null) 2HD:JdL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k@yh+v5  
Utility.log(header+" : "+con.getHeaderField(header)); 3A_G=WaED  
else =NadAyv  
break; ?-f,8Z|h  
} /,!<
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} Q^L) Vp"  
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+ ~"5!  
public void splitterStop() \/ErPi=g  
{ eIH$"f;L  
bStop = true; 6#U^<`  
} /'ZKST4  
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} V C-d0E0  
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/* M diwRi  
**FileAccess.java R:M,tL-l  
*//文件访问(定位，写) TkRm
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package NetFox; ziiwxx_  
import java.io.*; "oR@JbdX  
^XG*z?Tt  
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public class FileAccessI implements Serializable{ k[%aCGo  
9gy(IRGq/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 le8 #Z}p  
RandomAccessFile oSavedFile; 2Q@Y^t   
long nPos; y\D=Z N@  
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public FileAccessI() throws IOException Xh F_]  
{ %Ds+GM-  
this("",0); Ab2Q \+,  
} I-kWS4  
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public FileAccessI(String sName,long nPos) throws IOException uH:YKH':/  
{ Z+4D.bA  
oSavedFile = new RandomAccessFile(sName,"rw"); WF[bO7:  
this.nPos = nPos; 4t*so~  
oSavedFile.seek(nPos); 2:SO_O4C  
} v+xB7w  
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public synchronized int write(byte[] b,int nStart,int nLen) qtMD CXZ^n  
{ PyBD  
int n = -1; hr/o<#OW  
try{ r|eZv<6  
oSavedFile.write(b,nStart,nLen); @kxel`,$e  
n = nLen; $!B}$I;cd  
} ;j9\b9m  
catch(IOException e) `XKVr  
{ x#*QfE/E(@  
e.printStackTrace (); 3I $>uR  
} 9t$]X>}  
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AX
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return n; H,y4`p 0  
} tU:EN;H  
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} &%mXYj3y5  
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/* Nd@~>&F  
**SiteInfoBean.java Ef)yQ  
*/ 4a''Mi`u  
package NetFox; t9cl"
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public class SiteInfoBean { 4(8xjL:  
+&i +Mpb  
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private String sSiteURL; //Site's URL <hx+wrv  
private String sFilePath; //Saved File's Path Ig6T g ?  
private String sFileName; //Saved File's Name :j^FJ@2_  
private int nSplitter; //Count of Splited Downloading File x@KZ]  
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public SiteInfoBean() )]htm&q5  
{//nSplitter的缺省值为5 j)C:$  
//default value of nSplitter is 5 N?P%-/7  
this("","","",5); ye}p~&  
} >e,mg8u6$  
$I9qgDJ)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
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{ UVQ7L9%?f  
sSiteURL= sURL; cyM-)r@YQV  
sFilePath = sPath; kg
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sFileName = sName; [U/(<?F{(  
this.nSplitter = nSpiltter;  ._O  
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w= P9FxB  
} L+}n@B  
$*R/tJ.  
{0"YOS`3AX  
public String getSSiteURL() *%/~mSx  
{ ({WyDu&=  
return sSiteURL; y|wlq3o  
} ]X Z-o>+,  
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public void setSSiteURL(String value) X;v$5UKU  
{ Vv1|51B  
sSiteURL = value; mtz#}qD66  
} $-}e; VZb  
*^%Q0mU[  
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public String getSFilePath()  -!W<DJ*  
{ 9}a_:hAy/  
return sFilePath; O3DmNq$dz  
} a2Pf/D]n  
,JU@|`  
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public void setSFilePath(String value) L@`ouQ"sa  
{ ~w8JH2O  
sFilePath = value; sm[94,26  
} ';Zi@f"  
~vlype3/EF  
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public String getSFileName() >{\7&}gz  
{ ./Q,  
return sFileName; %NL^WG:  
} ;bHV  
_=CZR7:O  
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public void setSFileName(String value) [(1c<b2r  
{ 9z)5Mdf1j  
sFileName = value; ]BR,M4   
} U!U$x74D5  
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public int getNSplitter() mU}F!J#6  
{ 4jD2FFG- G  
return nSplitter; F1L:,.e`  
} <! )**  
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}!IL]0q  
public void setNSplitter(int nCount) ]Oq[gBL"A  
{ orOt>5}b<  
nSplitter = nCount;
y ]?V~%  
} Sb~MQ_  
} 23~Sjr  
^%O]P`$  
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/* Y>'|oygHA  
**Utility.java !%$`Eq)M^7  
*/ " Hd|7F'u=  
package NetFox; $56,$K`H  
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public class Utility { w*R$o
 
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public Utility() @')[
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{ K4kMM*D  
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} ght$9>'n  
ti#7(^
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//线程睡眠 ~
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public static void sleep(int nSecond) qT+%;(  
{ '3g[]M@M  
try{ #'y#"cmQ.  
Thread.sleep(nSecond); 0\eIQp  
} ?"g!  
catch(Exception e) /FRm2m83  
{ =uS9JU^E  
e.printStackTrace (); HPZ}*m'  
} pej|!oX  
} 4T ~
}  
62zYRs\Y)X  
//日志 9gmW&{6q  
public static void log(String sMsg) !_Wi!Vr_  
{ &wV]
"&-  
System.err.println(sMsg); o7$'cn  
} \ZkA>oO".  
;XBI{CW  
]iUxp+  
public static void log(int sMsg) h5^Z2:#  
{ ,LnII  
System.err.println(sMsg); OOo3G~2r  
} k=jk`c{<[  
} r8xv#r1  
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/* 6}FP  
**TestMethod.java Jt}Bpg!J  
*/ 32`{7a3!=  
package NetFox; V)[@98T_4?  
6|PrX L&  
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public class TestMethod { 7Mg=b%IYs  
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,&  
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public TestMethod() %yv<y+yP~  
{ ///xx/weblogic60b2_win.exe ]d! UJ&<?  
try{ qm"rY\:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =ACVE;L?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 24z< gO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &tg&5_  
fileFetch.start(); FG.em  
} +nJgl8'^y  
catch(Exception e){e.printStackTrace ();} 2h5nMI]'  
+lHjC$  
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} iT2B'QI=<  
 J4fi'  
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public static void main(String[] args) hpO`]  
{ o!kbK#k  
new TestMethod(); ~f$|HP}  
} SAy=WV  
} e&&53?  
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