http断点续传简单实现（java)

/* bQ|#_/?  
**SiteFileFetch.java N(:EK  
*/ doxdRYKL  
package NetFox; |o;j0  
import java.io.*; P3,Z5|)  
import java.net.*; X~IRpzC  
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public class SiteFileFetch extends Thread { (`q6G d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (R;) 9I\  
long[] nStartPos; //开始位置 {UV<=R,E  
long[] nEndPos; //结束位置 Lic{'w&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CYTuj>Ww  
long nFileLength; //文件长度 !:g>CDA  
boolean bFirst = true; //是否第一次取文件 $ g1wK}B3  
boolean bStop = false; //停止标志 Zh@4_Z9n!  
File tmpFile; //文件下载的临时信息 ]noP  
DataOutputStream output; //输出到文件的输出流 iECC@g@a  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &F<J#cfe8  
public SiteFileFetch(SiteInfoBean bean) throws IOException BCa90  
{ 1{\,5U&  
siteInfoBean = bean; p ?Ij-uo"o  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WcZo+r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =hOj8;2  
if(tmpFile.exists ()) A
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{ yPzULO4  
bFirst = false; hX'z]Am<  
read_nPos(); _4XoUE\\  
} f2R+5`$  
else -Z/6;2
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{ laD.or  
nStartPos = new long[bean.getNSplitter()]; &8:iB {n  
nEndPos = new long[bean.getNSplitter()]; [`Qp;_K?t  
} n}ZBU5_  
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} )"i>R ~*  
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public void run() n8;G,[GM80  
{ oC@"^>4  
//获得文件长度 w/^0
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//分割文件 SS45<!iy  
//实例FileSplitterFetch Fb\2df{@  
//启动FileSplitterFetch线程 sa0^1$(<  
//等待子线程返回 Rrs`h `'-  
try{ =JySY@
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if(bFirst) /RXk[m-  
{ ![X.%  
nFileLength = getFileSize(); ]Nd'%M  
if(nFileLength == -1) tx|"v|&e2  
{ 56O<CgJF<  
System.err.println("File Length is not known!"); )z4kP09  
} !5' 8a5  
else if(nFileLength == -2) a dz;N;rIY  
{ gqHH Hh  
System.err.println("File is not access!"); 3'
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} Bgo"JNM  
else -f|+
 
{ (

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for(int i=0;i<nStartPos.length;i++) 00.iMmJ  
{ v&CO#vK5.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b3 %&   
} <7
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for(int i=0;i<nEndPos.length-1;i++) :[X}.]"  
{ Ie`SWg*WL  
nEndPos = nStartPos[i+1]; &:cTo(C'  
} O7<V@GL+  
nEndPos[nEndPos.length-1] = nFileLength; CSk  
} >{LJ#Dc6  
} Cn./Naq  
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//启动子线程 ^v'g~+@o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; aD2CDu  
for(int i=0;i<nStartPos.length;i++) BB73'W8y  
{ te)g',#lT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zm)CfEF 8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^) b7m  
nStartPos,nEndPos,i); +G=C~X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8L9S^ '  
fileSplitterFetch.start(); D^R! |K/  
} b09#+CH?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |\r\i&|g1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L+0N@`nRF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6
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nEndPos = " + nFileLength); UgP=k){  
// fileSplitterFetch[nPos.length-1].start(); I`n1M+=%  
+IOK
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`v/tf|v6  
//等待子线程结束 eQ)ioY  
//int count = 0; i7w}
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//是否结束while循环 3bI|X!j  
boolean breakWhile = false; k9VQ6A  
3z/O`z  
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while(!bStop) ZsK'</7  
{ +[l{C+p  
write_nPos(); bM3'm$34  
Utility.sleep(500); MT#[ -M\  
breakWhile = true; 7zkm  
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for(int i=0;i<nStartPos.length;i++) =L; n8~{@y  
{  q&Ua(I  
if(!fileSplitterFetch.bDownOver) J`D<  
{ V:"\(Y  
breakWhile = false; va*>q-QCr  
break; cF<DUr)Ve  
} pcxl2I  
} 7QL) }b.H  
if(breakWhile) >5@ 0lYhH  
break; I8pxo7(-  
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//count++; :w`i  
//if(count>4) 8#JyK+NU  
// siteStop(); wYxFjXm  
} >8HRnCyp/  
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System.err.println("文件下载结束！"); * jNu?$  
} nOoh2jUM  
catch(Exception e){e.printStackTrace ();} E=U^T/  
} ^~kFC/tQ  
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//获得文件长度 U?m?8vhR6(  
public long getFileSize() _@3O`
 
{ 5<ya;iK  
int nFileLength = -1; 9mtC"M<   
try{ o>k-~v7  
URL url = new URL(siteInfoBean.getSSiteURL());  u^eC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _"e( ^yiK  
httpConnection.setRequestProperty("User-Agent","NetFox"); vH:+  
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int responseCode=httpConnection.getResponseCode(); g
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if(responseCode>=400) 7^}Z%c  
{ ea;c\84_N  
processErrorCode(responseCode); Tf]VcEF  
return -2; //-2 represent access is error I)4|?tb?  
} Dg4^ C  
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String sHeader; u6&Ixi/s'  
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for(int i=1;;i++) Yy:sZJ  
{ =|zyi|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); us *l+Jw,m  
//Utility.log(in.readLine()); $R}iL  
sHeader=httpConnection.getHeaderFieldKey(i); :r+ 1>F$o  
if(sHeader!=null) ^\t">NJ^  
{ .3SjkC4I  
if(sHeader.equals("Content-Length")) )W7H{#  
{ ;7{wa]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4>eg@sN  
break; pv.),Iv-68  
} X~VZ61vNu  
} >R!I  
else d~s-;T  
break; \evgDZf  
}
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} <^
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catch(IOException e){e.printStackTrace ();} GdwHm  
catch(Exception e){e.printStackTrace ();} =7Gi4X%  
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Utility.log(nFileLength); X7!A(q+h  
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i; uM!d}  
return nFileLength; ;Awzm )Q  
} ;{u#~d}  
( I~XwP&  
8#3cmpx4  
//保存下载信息（文件指针位置） b8Ad*f\  
private void write_nPos() `l@t3/  
{ h.%Qn vL  
try{ : .e
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output = new DataOutputStream(new FileOutputStream(tmpFile)); *J-jr8&  
output.writeInt(nStartPos.length); N^j''siB  
for(int i=0;i<nStartPos.length;i++) z@LP9+?dE  
{ #.K&]OV/88  
// output.writeLong(nPos); PltPIu)F  
output.writeLong(fileSplitterFetch.nStartPos); uB9+E%jOdQ  
output.writeLong(fileSplitterFetch.nEndPos); G!Q)?N   
} {i?K~| h  
output.close(); a.Vs>1  
} #rC+13  
catch(IOException e){e.printStackTrace ();} P=i |{vv(  
catch(Exception e){e.printStackTrace ();} 3Sb%
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} V3nv5/6  
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//读取保存的下载信息（文件指针位置） ^E8Hv  
private void read_nPos() L^Af3]]2  
{ D7oV&vXg  
try{ g[Y$SgJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !SNtJi$;v  
int nCount = input.readInt(); p_N=V. w  
nStartPos = new long[nCount]; z#!Cg*K(  
nEndPos = new long[nCount]; 5rhdm?Ls0  
for(int i=0;i<nStartPos.length;i++) \%*y+I0>  
{ /qY(uPJ  
nStartPos = input.readLong(); }jXUd=.Nu  
nEndPos = input.readLong(); l0,O4k2'  
} nP /$uj  
input.close(); qd;f]ndo  
} 'S ;vv]}Gs  
catch(IOException e){e.printStackTrace ();} N{@eV][Q  
catch(Exception e){e.printStackTrace ();} DA\O,^49h  
} ,4UJ|D=J  
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private void processErrorCode(int nErrorCode)  iSax-Mc  
{ b(,[g>xH  
System.err.println("Error Code : " + nErrorCode); a_x6 v*  
} 9dv~WtH>5  
s!
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//停止文件下载 Sy~Mh]{E  
public void siteStop() IT"jtV  
{ {hR23eE)#  
bStop = true; \/GY0s  
for(int i=0;i<nStartPos.length;i++) ld6@&34  
fileSplitterFetch.splitterStop(); EORAx  
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/otgFQ_  
}  #pK)  
} Sn,z$-;h;  
//负责部分文件的抓取 F3'G9Xf8Q=  
**FileSplitterFetch.java (x!bZ,fu  
*/ {,X(fJ  
package NetFox; sa?;D  
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*l} 0x@  
import java.io.*; E{B<}n|}&  
import java.net.*; u?i1n=Ne  
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public class FileSplitterFetch extends Thread { q fe#kF9  
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String sURL; //File URL Ks-><-2+N  
long nStartPos; //File Snippet Start Position 19DW~kvYk  
long nEndPos; //File Snippet End Position 2;tp>,
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int nThreadID; //Thread's ID |F`'m":$m  
boolean bDownOver = false; //Downing is over V-|}.kOH2  
boolean bStop = false; //Stop identical '`"&RuB  
FileAccessI fileAccessI = null; //File Access interface 0]HIc  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c9'b`#'  
{ Ws@s(5r  
this.sURL = sURL; x@)u:0  
this.nStartPos = nStart; HmKE>C/  
this.nEndPos = nEnd; ySZ)yT  
nThreadID = id; j|9 2 g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I1jF`xQ&0  
} w4mL/j  
|d8o<Q  
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public void run() (@9-"W  
{ `x3c},'@k  
while(nStartPos < nEndPos && !bStop) R!ij CF\  
{ |V5H(2/nk  
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try{ :csLZqn[  
URL url = new URL(sURL); n_j[hA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <T>f@Dn,  
httpConnection.setRequestProperty("User-Agent","NetFox"); WqO*vK!t  
String sProperty = "bytes="+nStartPos+"-"; ^q$sCt}  
httpConnection.setRequestProperty("RANGE",sProperty); L\5n!(,0  
Utility.log(sProperty); t!LvV.g+  
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InputStream input = httpConnection.getInputStream(); &M0v/!%L  
//logResponseHead(httpConnection); ]MyWB<9M  
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byte[] b = new byte[1024]; |{(ynZ]R  
int nRead; r=;k[*;{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lK0coj1+  
{ VPuzu|  
nStartPos += fileAccessI.write(b,0,nRead); (msJ:SG  
//if(nThreadID == 1) &%<G2x$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tQ"PCm  
} ,h"M{W$  
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Utility.log("Thread " + nThreadID + " is over!"); d?JVB  
bDownOver = true; 1x]G/I*  
//nPos = fileAccessI.write (b,0,nRead); {.AFg/Z  
} >*&[bW'}?  
catch(Exception e){e.printStackTrace ();} \W4SZR%u  
} OWU]gh@r  
} }
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;XjKWM;  
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//打印回应的头信息 3't?%$'5  
public void logResponseHead(HttpURLConnection con) IlY,V  
{ TX;|g1K  
for(int i=1;;i++) =6'A8d  
{ c`TgxMu  
String header=con.getHeaderFieldKey(i); v?}/WKe+0  
if(header!=null) z 'j%.Dd8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xZhh%~  
Utility.log(header+" : "+con.getHeaderField(header)); 0z.&  
else 7ORwDR,`5  
break; B; ~T|exu  
} z[B7k%}  
} YS9|J=!~  
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{"s8X(#_sC  
public void splitterStop() 1cPi>?R:  
{ i^yQ; 2-  
bStop = true; w] VvH"?  
} OF)X(bi4j  
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} nG2RBeJV  
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/* w!Z3EA;`  
**FileAccess.java
]
>!]X*\9  
*//文件访问(定位，写) U`D"L4},.  
package NetFox; H&I0\upd  
import java.io.*; /IgTmXxxj  
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~Oolm_+{}  
public class FileAccessI implements Serializable{ '8Yx  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r3|vu"Uei  
RandomAccessFile oSavedFile; r]TeR$NJ  
long nPos; mIOx)`
$  
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public FileAccessI() throws IOException O*CKyW_$t  
{ [qc90)^Q,  
this("",0); `":< ]lj  
} 'kp:yI7w  
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public FileAccessI(String sName,long nPos) throws IOException ezFyd'P  
{ zdtzR<X  
oSavedFile = new RandomAccessFile(sName,"rw");
{R(q7ALR  
this.nPos = nPos;
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oSavedFile.seek(nPos); 6x_8m^+m  
} F<oJ
  
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public synchronized int write(byte[] b,int nStart,int nLen) {jbOcx$t  
{ Fq
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int n = -1; pDW .Pav  
try{ VF;%Z  
oSavedFile.write(b,nStart,nLen); _bW#* Y5  
n = nLen; %h^; "|Z  
} ugOcK Gf  
catch(IOException e) Ta~Ei=d^  
{ bjbm"~  
e.printStackTrace (); w}+j
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} 5'6Oan7dL:  
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return n; ;R}:2  
} IU&n!5d$)|  
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} s(-$|f+s  
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/* lRn>/7sg$  
**SiteInfoBean.java b16\2%Ea1  
*/ zK?[6n89f  
package NetFox; kz]qk15w  
%-> X$,Q :  
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public class SiteInfoBean { 6~j6M4*  
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private String sSiteURL; //Site's URL .-uH ax0  
private String sFilePath; //Saved File's Path ~#Vrf0w/  
private String sFileName; //Saved File's Name ;=aj)lemCr  
private int nSplitter; //Count of Splited Downloading File _A1r6  
1#6c sZW5  
:D;BA  
public SiteInfoBean() eWE7>kwh  
{//nSplitter的缺省值为5 624l5}@:  
//default value of nSplitter is 5 ELPzqBI  
this("","","",5); 6ID@0  
} ZE#A?5lb  
/aNlr>^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fn;`Vit#  
{ c#Y/?F2p  
sSiteURL= sURL; PIl:z?q({  
sFilePath = sPath; g=Rl4F]  
sFileName = sName; gM&XVhQJ\  
this.nSplitter = nSpiltter; *i?#hTw  
9n%vz@X  
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} "KS
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53  
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public String getSSiteURL() &( aw  
{ .7_<0&kW  
return sSiteURL; 3vepJ)D (  
} SN'j?-  
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public void setSSiteURL(String value) AhWcJD]  
{ 2Jm#3zFYz3  
sSiteURL = value; E.45s? r  
} `r+zNJ@q  
~nDbWv"  
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public String getSFilePath() Z^wogIAV  
{ wO.T"x%X  
return sFilePath; "V'<dn  
} B OKY X  
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public void setSFilePath(String value) :"{("!x  
{ eaB6e@]@  
sFilePath = value; N3"O
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} Vq4g#PcG  
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public String getSFileName() LYhjI  
{ 'ioX,
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return sFileName; UXgeL2`;  
} V(wm?Cc]  
/fgy07T  
rU/8R'S  
public void setSFileName(String value) (J}tCqP  
{ E?v:7p<  
sFileName = value; /#TtAkH  
} Bre:_>*  
#:[^T,YD0  
q|h#J}\  
public int getNSplitter() x`n7D  
{ +@G#Z3;l!  
return nSplitter; (}
*1,N!#  
} M$,4B  
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djmd @{Djt  
public void setNSplitter(int nCount) (_IP
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{ Z@(m.&ZRx  
nSplitter = nCount; <!;NJLe`  
} r?7tI0  
} {?X:?M_  
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/* *{<460`!q  
**Utility.java wDp5HZ>  
*/ 0H!J  
package NetFox; -RI&uFqOI  
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yi.GD~69  
public class Utility { SR>(GQ,m0;  
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public Utility() 03Uj0.Z|7  
{ s'B$/qCkR  
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} BK]5g[   
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//线程睡眠 ,,8'29yEq  
public static void sleep(int nSecond) bt'lT  
{ tZ>'tE   
try{ /JjSx/  
Thread.sleep(nSecond); '+&!;Jj,  
} xcE2hK/+  
catch(Exception e) M.qE$  
{ XcFu:B  
e.printStackTrace (); weH;,e*r  
} N1fPutl$a
 
} \%}w7
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//日志 W %<,GV  
public static void log(String sMsg) zD@RW<M  
{ ,8[R0wsBaz  
System.err.println(sMsg); +OaBA>Jh9  
} b?,''t  
JuDadIrd{  
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public static void log(int sMsg) EG!Nsb^,  
{ "M}3T?0 O  
System.err.println(sMsg); tS3!cO\  
} OE/r0C<&  
} ,5& Rra/  
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JD)wxoeg  
/* @Zzg^1Ilpu  
**TestMethod.java "Wg5eML0  
*/ -&h<t/U  
package NetFox; /lLG
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&SMM<^P.  
$Zn>W@\  
public class TestMethod { :Qu.CvYF  
oM!zeJNA  
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public TestMethod() AzMX~cd  
{ ///xx/weblogic60b2_win.exe .A F94OlE/  
try{ 0ZJrK\K;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6m0-he~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k r5'E#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Wgm{ ]9Q  
fileFetch.start(); wvI}|c  
} (V>/[Ev  
catch(Exception e){e.printStackTrace ();} x-T7 tr&(  
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} F%I*m^7d  
uQl=?085  
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public static void main(String[] args) Og1Hg B3v  
{ |@rYh-5  
new TestMethod(); PmA_cP7~  
} x75 3o\u!  
} ]]hsLOM]  
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