http断点续传简单实现（java)

/* Y'{}

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**SiteFileFetch.java jG~
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*/ :i4AkBNK  
package NetFox; 0K'{w]Q  
import java.io.*; 5vFM0  
import java.net.*; $l2`@ia"  
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public class SiteFileFetch extends Thread { cLEd-{x  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (gnN</%  
long[] nStartPos; //开始位置 Atb`Q'Yrw  
long[] nEndPos; //结束位置 K@<*m!%<2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _TLspqi  
long nFileLength; //文件长度 Nw9@
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boolean bFirst = true; //是否第一次取文件 E[WU  
boolean bStop = false; //停止标志 #.rkvoB0N  
File tmpFile; //文件下载的临时信息 kebk f,`p  
DataOutputStream output; //输出到文件的输出流 W[I$([  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） p5jR;nOZ%l  
public SiteFileFetch(SiteInfoBean bean) throws IOException !E&l=*lM.  
{
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siteInfoBean = bean; vf zC2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [[HCP8Wk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fF(AvMsO  
if(tmpFile.exists ()) O=t~.]))  
{ t{>#)5Pqv  
bFirst = false; \6
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read_nPos(); 0$ON`Vsu|  
} &@,lF{KTL  
else X~UL$S;  
{ pV(k6h  
nStartPos = new long[bean.getNSplitter()]; Z^]jy>dj  
nEndPos = new long[bean.getNSplitter()]; c(uDkX  
} }W@refS  
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} P4HoKoj2`  
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public void run() -.r"|\1X  
{ GMg!2CIU  
//获得文件长度 3$xpZm60  
//分割文件 TE;f*!  
//实例FileSplitterFetch KTt+}-vP^  
//启动FileSplitterFetch线程 Zr1"'+-  
//等待子线程返回 (u^8=#  
try{ etT9}RbQ  
if(bFirst) \?oT.z5VG&  
{ z Ohv>a  
nFileLength = getFileSize();  71@kIJI  
if(nFileLength == -1) w>8HS+  
{ c0Bqm  
System.err.println("File Length is not known!"); wm^1Fn--  
} 
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else if(nFileLength == -2) w,X)g{^T  
{ SHs [te[  
System.err.println("File is not access!"); T*mR9 8i  
} m_Pk$Vwx  
else !yT=*Cj4  
{ qtdkK LT  
for(int i=0;i<nStartPos.length;i++) _h4]gZ  
{ q6N{N
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); akk*f+TD`  
} FAL#p$y}  
for(int i=0;i<nEndPos.length-1;i++)  ZB|s/  
{ B8eZ}9X  
nEndPos = nStartPos[i+1]; qE3Ud:j  
} ]zVQL_%,  
nEndPos[nEndPos.length-1] = nFileLength; C[<{>fl)  
} 'zav%}b]L  
} p+<qI~  
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//启动子线程  ]Tb?z&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k~so+k&=b  
for(int i=0;i<nStartPos.length;i++) ,tQNL\t  
{ Y@:l!4DI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _f8H%Kgk;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5=8v\q?)c  
nStartPos,nEndPos,i); t\LE\[XM>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 50dN~(;p  
fileSplitterFetch.start(); IP$eJL[&D"  
} JBA{i45x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xv Xci W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8\9W:D@"x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kssRwe%>;  
nEndPos = " + nFileLength); ?*$uj(  
// fileSplitterFetch[nPos.length-1].start(); {ZSAPq4)L  
n|?sNM<J3  
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//等待子线程结束 E.;Hm;  
//int count = 0; n:B)
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//是否结束while循环 <m^a ?q^  
boolean breakWhile = false; *1!'ZfT;  
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while(!bStop) +zbCYA  
{ :R +BC2x  
write_nPos(); n7B2rRJH  
Utility.sleep(500); lK/4"&  
breakWhile = true; ,aD~7QX1:  
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v FQ]>nX  
for(int i=0;i<nStartPos.length;i++) .SmG)5U]  
{ 88<d<)7t  
if(!fileSplitterFetch.bDownOver) yPT o,,ca=  
{ 5D=U.UdR  
breakWhile = false; ]@cI_n  
break; ZvQZD=,F  
} r_+!3   
} uH?4d!G  
if(breakWhile) Xjxa 2D  
break; !]}C!dXd  
j@#RfVx  
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//count++; 8@+<W%+th  
//if(count>4) N-b'O`C  
// siteStop(); su
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} %scIZCrI~  
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System.err.println("文件下载结束！"); ns~bz-n  
} -6WSYpHV  
catch(Exception e){e.printStackTrace ();} AxH`4=3<  
} BMQ4i&kF|  
~N}Zr$D  
6AdUlPM  
//获得文件长度 Drf Au  
public long getFileSize() #@w/S:KbJt  
{ pYm#iz  
int nFileLength = -1; 7O%^4D  
try{ _a9oHg  
URL url = new URL(siteInfoBean.getSSiteURL()); _g9j_
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZU0*iA  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4`9ROC  
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int responseCode=httpConnection.getResponseCode(); I(kEvfxc"  
if(responseCode>=400) 6C"zBJcGc  
{ Y1>OhHuN  
processErrorCode(responseCode); RTbV!I  
return -2; //-2 represent access is error _*g
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} ~iiDy;"  
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String sHeader; -R1;(n)  
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for(int i=1;;i++) B 5qy4MFWs  
{ tI^[|@,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pRxVsOb  
//Utility.log(in.readLine()); FIAmAZH}_  
sHeader=httpConnection.getHeaderFieldKey(i); %jf|efxo  
if(sHeader!=null) 7rbw_m`12-  
{ T*Ge67  
if(sHeader.equals("Content-Length")) = =Q*|L-g  
{ 9 `bLQd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P0_Ymn=&  
break; 7BqP3T=&_  
} )+Z.J]$O-  
} J4j:nd  
else z19%!k  
break; C|g1:#0  
} ]oz>/\!  
} qf ]le]J  
catch(IOException e){e.printStackTrace ();} I*JJvqh
  
catch(Exception e){e.printStackTrace ();} F\&^(EL  
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Utility.log(nFileLength); a{}#t}  
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return nFileLength; HE_
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} (E,[Ad,$  
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//保存下载信息（文件指针位置） "D
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private void write_nPos() =+?OsH v  
{ s S3RK  
try{ W?!rqo2SP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K5^zu`19  
output.writeInt(nStartPos.length); ez%:>r4  
for(int i=0;i<nStartPos.length;i++) 9M1DE  
{ ~Al3Dv9x  
// output.writeLong(nPos); @x A^F%(  
output.writeLong(fileSplitterFetch.nStartPos); :yi} CM4  
output.writeLong(fileSplitterFetch.nEndPos); |=~mRqG  
} lfd-!(tXD  
output.close(); JV4fL~  
} #h9Gl@|  
catch(IOException e){e.printStackTrace ();} yt,Ky8y1  
catch(Exception e){e.printStackTrace ();} U7g,@/Qx  
} q(R|3l^6T  
w@6y.v1I{  
#j+cl'  
//读取保存的下载信息（文件指针位置） .!lLj1?p  
private void read_nPos() a+O?bO  
{ aR@+Qf  
try{ Pf?&ys6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cH:&S=>h  
int nCount = input.readInt(); n_Y7*3/b-o  
nStartPos = new long[nCount]; L*|P'  
nEndPos = new long[nCount]; @;y@Hf'Jv  
for(int i=0;i<nStartPos.length;i++) [ybK  
{ o /1+ }f  
nStartPos = input.readLong(); =WZ9|
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nEndPos = input.readLong(); j` * bz-  
} -k2|`t _  
input.close(); ?|}qT05  
} d( ru5*p  
catch(IOException e){e.printStackTrace ();} ;l0%yg/}  
catch(Exception e){e.printStackTrace ();}
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} :f_oN3F p  
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private void processErrorCode(int nErrorCode) -byaV;T?"  
{ hgDFhbHtd6  
System.err.println("Error Code : " + nErrorCode); >o&%via}  
} ?8< =.,r  
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//停止文件下载 y@2"[fo3~  
public void siteStop() %1{O  
{ ''!j:49  
bStop = true; hBaG*J{  
for(int i=0;i<nStartPos.length;i++) {-]K!tWda  
fileSplitterFetch.splitterStop(); ;p<BiC$b  
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} (
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} ;Oq>c=9%  
//负责部分文件的抓取 `C-8zA  
**FileSplitterFetch.java i&%dwqp  
*/ b KDD29  
package NetFox; 9PG{>W$M  
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import java.io.*; usoyH0t!?  
import java.net.*; qx*b\6Rt  
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public class FileSplitterFetch extends Thread { 4OO^%`=)M'  
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String sURL; //File URL ZnRj}y  
long nStartPos; //File Snippet Start Position @7Ln1v  
long nEndPos; //File Snippet End Position >Lo'H
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int nThreadID; //Thread's ID .A6pPRy e  
boolean bDownOver = false; //Downing is over 9asA-'fZ  
boolean bStop = false; //Stop identical (sH4T>  
FileAccessI fileAccessI = null; //File Access interface -=UvOzw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pa?AKj]  
{ rTJqw@]#WH  
this.sURL = sURL; H+gB|  
this.nStartPos = nStart; Ro<5c_k  
this.nEndPos = nEnd; L>hLYIW  
nThreadID = id; M\JAB ;A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7`)RBhGB  
} 3|)cT1ej  
\S?-[v*{  
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public void run() 6e5A8e8"]  
{ w_~tY*IwB  
while(nStartPos < nEndPos && !bStop) BV/ ^S.~  
{ asy:[r"  
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try{ 1sJz`+\  
URL url = new URL(sURL); E6T=lwOZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2pSp(@N3  
httpConnection.setRequestProperty("User-Agent","NetFox"); B(eiRr3  
String sProperty = "bytes="+nStartPos+"-"; T0b/txS  
httpConnection.setRequestProperty("RANGE",sProperty); R@>^t4#_Q0  
Utility.log(sProperty); ^)|tf\4  
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InputStream input = httpConnection.getInputStream(); b%C7 kL-  
//logResponseHead(httpConnection); U!BZsVx  
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byte[] b = new byte[1024]; )`gxaT>&l  
int nRead; H3iYE~^#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {S@, ,  
{ h+YPyeAs  
nStartPos += fileAccessI.write(b,0,nRead); &=T>($3r94  
//if(nThreadID == 1) '*&V7:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ExL7 ]3r  
} ).Iifu|
ks  
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Utility.log("Thread " + nThreadID + " is over!"); ]a*26AbU+  
bDownOver = true; hX-^h2
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//nPos = fileAccessI.write (b,0,nRead); rCA0c8  
} ICG:4n(,  
catch(Exception e){e.printStackTrace ();} pk;S"cnk  
} GQjU="+  
} c7tO'`q$e  
c@j3L23B  
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//打印回应的头信息 lD# yXLaC\  
public void logResponseHead(HttpURLConnection con) tm_\(  
{ ir|L@Jj,  
for(int i=1;;i++) 4Y G\<Zf  
{ {8%KO1xB  
String header=con.getHeaderFieldKey(i); HuN_$aP  
if(header!=null) oIE3`\xS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9c0
  
Utility.log(header+" : "+con.getHeaderField(header)); R-4#y%k<  
else <p`
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break; Dv^M/z2&[  
} k@>(sXs  
} )hVn/*mH  
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public void splitterStop() &*Kk> 4  
{ Q } 0_}W  
bStop = true; [8acan+ 2l  
} 9sv#TT5V  
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} a'>n'Y~E  
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8ddBQfCY  
/* #B_H/9f(  
**FileAccess.java H5jk#
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*//文件访问(定位，写) LW
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package NetFox; yhnPS4DC  
import java.io.*; {t]8#[lo  
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public class FileAccessI implements Serializable{ 8@FgvWC  
M%$-c3x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `C^0YGO%  
RandomAccessFile oSavedFile; PT4iy<  
long nPos; h`p=~u +  
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public FileAccessI() throws IOException l
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{ 4#B56f8  
this("",0); wkJ@#jD*[  
} (7??5gjh  
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public FileAccessI(String sName,long nPos) throws IOException %9L+ Q1o  
{ _.m|Ml,`{  
oSavedFile = new RandomAccessFile(sName,"rw"); 6_;n b
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this.nPos = nPos; [mG!-
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oSavedFile.seek(nPos); :"K9(XKKU  
} fzN?X=  
y (%y'xBP  
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public synchronized int write(byte[] b,int nStart,int nLen) ' Yy+^iCus  
{ <(45(6fQ  
int n = -1; vI"BNC*Q1  
try{ }YU\}T-P  
oSavedFile.write(b,nStart,nLen); 'XOWSx;Y  
n = nLen; fM(~>(q&  
} "|E'E"_1  
catch(IOException e) \23m*3"W  
{ p@d_Ru  
e.printStackTrace (); >YcaFnY  
} .kfx\,lgm  
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;):E 8;B)  
return n; 4S* X=1  
} ~L_1&q^4!i  
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} i G%R'/*  
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}:]CXrdg>  
/* EO/41O  
**SiteInfoBean.java T#&X7!4  
*/ ]na$n[T/I  
package NetFox; NBw{
 
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public class SiteInfoBean {
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private String sSiteURL; //Site's URL }>b@=5O  
private String sFilePath; //Saved File's Path wZ_"@j<  
private String sFileName; //Saved File's Name }V 4u`=  
private int nSplitter; //Count of Splited Downloading File 8\+DSA  
`~NjBtQ  
G#1W":|`  
public SiteInfoBean() "EZpTy}Ee  
{//nSplitter的缺省值为5 D8WKy  
//default value of nSplitter is 5 p&
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this("","","",5); |z0% q2(  
} $3cZS  
^W~8)Rbf  
VU+=b+B~m  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w8`B}Dr23  
{ jcRe),  
sSiteURL= sURL; :OA;vp~$x  
sFilePath = sPath; G(bl)p^  
sFileName = sName; w,OPM}) il  
this.nSplitter = nSpiltter; xZVZYvC,t  
$dsLU5]1o  
/RWD\u<l  
} <00=bZzX  
SErh"~[  
~G.MaSm  
public String getSSiteURL() WwxV}?Cf+  
{ @c).&7  
return sSiteURL; yqP=6   
} x4v&%d=M  
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public void setSSiteURL(String value) ~
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{ 1yFIIj:^|  
sSiteURL = value; =o'g5Be<F  
} b)r;a5"<5  
lWBewnLKE  
h+j*vX/!  
public String getSFilePath() & u6ydN1xe  
{ KWM}VZY:Z  
return sFilePath; 7R,;/3wWjG  
} Uz%ynH  
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P  
q(v|@l|)yO  
public void setSFilePath(String value) bEmzigN[  
{ zT93Sb  
sFilePath = value; .eyJ<b9  
} f*VXg[&\\F  
C 1)+^{7ef  
2#s8Dxt  
public String getSFileName() Oc5f8uv  
{ U
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return sFileName; 5tEkQ(Ei8  
} ;s8\F]K  
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C u
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public void setSFileName(String value) B;2#Sa.  
{
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sFileName = value; KDj/
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} 86a,J3C[  
BnaI30-  
;J:*r0  
public int getNSplitter() \ rKUPI\  
{ cg9*+]rc  
return nSplitter; =)a%,H  
} ^)h&s*  
+{#Z^y6&  
KEf1GU6s  
public void setNSplitter(int nCount) ;j+*}|!  
{ xc7Rrh]}  
nSplitter = nCount; '}-QZ$|*  
} 9Q\RCl_1  
} F)@zo/u5L  
*e:2iM)8~  
VKg9^%#b`[  
/* kYR^  
**Utility.java b;NVvc(  
*/ fUPYCw6F  
package NetFox; c{qTVi5e  
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public class Utility { $x#
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</R@)_'  
public Utility() A$L:,b(  
{ bfkFk  
x'SIHV4M@Q  
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} H}(WL+7  
XinKG<3!  
//线程睡眠 $4og{  
public static void sleep(int nSecond) 'pF$6n;  
{ S"`{ JCW$  
try{ j
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Thread.sleep(nSecond); dCLNZq h6  
} /+WC6&  
catch(Exception e) %ofq  
{ ,wy;7T>ODd  
e.printStackTrace (); `,4YPjk^  
} 2EO9IxIf  
} ce719n$   
ZZc^~  
//日志 D&]xKx  
public static void log(String sMsg) xn)F(P 0kv  
{ }iLi5Qkx  
System.err.println(sMsg); %=V"
}P[  
} )Lk2tvr  
k?/!`  
RN;#H
_ q  
public static void log(int sMsg) z80*Ylx  
{ /q/^B>]  
System.err.println(sMsg); Kek%io  
} tCGA3t  
} P2U4,?_e  
?}EWfs
A  
mxe\+j#  
/* > kwhZ/x  
**TestMethod.java "chf\-!$  
*/ J%fJF//U  
package NetFox; a FWTm,)  
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^;?
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public class TestMethod { SCfk!GBVD  
ETR7%0$r  
?zVcP=p@  
public TestMethod() B}aW y&D  
{ ///xx/weblogic60b2_win.exe F)19cKx7  
try{ v[?gM.SF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9<"F3F0|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Urksj:N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nFro#qx  
fileFetch.start(); ucbtPTFYvr  
} 8 -w|~y';  
catch(Exception e){e.printStackTrace ();} *Tmqs@L  
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T>&dPVmG,  
} u!fZ>kS  
!A14\  
- 8jlh  
public static void main(String[] args) VRHS 4  
{ t*Z-]P  
new TestMethod(); 0t*PQ%  
} !L_xcov!Y  
} V=+p8nE0  
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