http断点续传简单实现（java)

/* SO<K#HfE$?  
**SiteFileFetch.java u"|nu!p`  
*/ `8bp6}OD,  
package NetFox; xEWa<P#.u  
import java.io.*; /7)G"qG~F~  
import java.net.*; 7+-}8&syu  
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public class SiteFileFetch extends Thread { 9h=WWu',  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l7um9@[4  
long[] nStartPos; //开始位置 ;.a)
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long[] nEndPos; //结束位置 8rNxd=!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HJrg  
long nFileLength; //文件长度 TI&J>/z;$  
boolean bFirst = true; //是否第一次取文件 /qze  
boolean bStop = false; //停止标志 .}>[Kr  
File tmpFile; //文件下载的临时信息 /bk} J:QRg  
DataOutputStream output; //输出到文件的输出流 >R-$JrU.=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 39eoL;O_  
public SiteFileFetch(SiteInfoBean bean) throws IOException Wm_-T]#_  
{ ^O"`.2O1  
siteInfoBean = bean; `Yve  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4D
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q+N @j]'  
if(tmpFile.exists ()) Y" |U$  
{ w$H
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bFirst = false; w]XBq~KO  
read_nPos(); IrM3Uh  
} kS!*kk*a  
else `-2`UGB-  
{ zg"ZXZ  
nStartPos = new long[bean.getNSplitter()]; 5%/%i}e~(  
nEndPos = new long[bean.getNSplitter()]; ArMe[t0$  
} GMI>$$<  
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} h|Qh/jCX  
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public void run() 7.-|3Wcg  
{ CeemR>\t  
//获得文件长度 ~8E rl3=5{  
//分割文件 T]k@g_  
//实例FileSplitterFetch r|8..Ll  
//启动FileSplitterFetch线程 lPP7w`[PA  
//等待子线程返回 tzPe*|m<  
try{ Hqv(X=6E0  
if(bFirst) ]F!,Jx  
{ d4tVK0 ~  
nFileLength = getFileSize(); :l{-UkbB  
if(nFileLength == -1) 2Hj]QN7"   
{ Jr zU-g  
System.err.println("File Length is not known!"); \!Pm^FD .  
} l-rI|0D#  
else if(nFileLength == -2) |ESe=G  
{ (>'d`^kjk  
System.err.println("File is not access!"); 6zSN?0c  
} .v'8G)6g  
else wu3ZSLY  
{ >d|W>|8e  
for(int i=0;i<nStartPos.length;i++) K+H82$ #  
{ Rlu;l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s RB8 jY  
} i=rW{0c%  
for(int i=0;i<nEndPos.length-1;i++) 6iOAYA=  
{ n&lLC&dL  
nEndPos = nStartPos[i+1]; Hr'#
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} mqpZby  
nEndPos[nEndPos.length-1] = nFileLength; ) Lv{  
} iFnM6O$(  
} hw1s^:|+2  
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//启动子线程 3dfSu'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +{&g|V  
for(int i=0;i<nStartPos.length;i++) L[efiiLh$  
{ 2*N# %ZUX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '=xl}v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w1Kyd?~%]  
nStartPos,nEndPos,i); ~j_H2+!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dx#N)?  
fileSplitterFetch.start(); $U1'n@/J  
} ^;e`ZtcI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TM9>r :j'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G1BVI:A&S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dBkB9nz  
nEndPos = " + nFileLength); qW9|&GuZ$  
// fileSplitterFetch[nPos.length-1].start(); 6Z 7$ZQ~  
v~SN2,h  
. x$` i  
//等待子线程结束 Iq9+  
//int count = 0; #i?TCO  
//是否结束while循环 p O.8>C%  
boolean breakWhile = false; ;
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while(!bStop) ZWv$K0agu  
{ Wp ]u0w  
write_nPos(); 3)sqAs(  
Utility.sleep(500); pa7fTd  
breakWhile = true; 6%>0g^`)9Y  
}[|"db  
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for(int i=0;i<nStartPos.length;i++) K)n(U9#  
{ "+Kr1nW  
if(!fileSplitterFetch.bDownOver) +oc}kv,h]  
{ Wr;)3K  
breakWhile = false; H]-nm+  
break; _oWenF  
} c?|/c9f  
} @<P[z[  
if(breakWhile) QH;
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break; jWQB~XQY  
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m&2m' =(  
//count++; !Lo{zTDW  
//if(count>4) '(Pbz   
// siteStop(); p^2pv{by  
} XHV+Y+VG  
1BF+sT3  
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System.err.println("文件下载结束！"); 7}xKiHh:  
} 3|C"F-'<  
catch(Exception e){e.printStackTrace ();} t]V)3Ww  
} R
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/  
j \SDw  
//获得文件长度 W[b/.u5z:  
public long getFileSize() k,H4<")H  
{ wvfCj6}S&  
int nFileLength = -1; v / a/  
try{ |Q$C%7  
URL url = new URL(siteInfoBean.getSSiteURL()); GYj`-t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gpPktp2  
httpConnection.setRequestProperty("User-Agent","NetFox"); hPl;2r  
/c09-$M  
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int responseCode=httpConnection.getResponseCode(); (7"qT^s3  
if(responseCode>=400) o)NWsUXf  
{ {KR/
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processErrorCode(responseCode); Z-WWp#b  
return -2; //-2 represent access is error y jb.6  
} d;f,vN(  
/(Y\ <  
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String sHeader; f+d{^-  
>$}nKPC,Y  
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for(int i=1;;i++) ]UM
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{ ;$Wa=wHb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #GTmC|[  
//Utility.log(in.readLine()); r
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sHeader=httpConnection.getHeaderFieldKey(i); n^'{{@&(v  
if(sHeader!=null) NKd):>d%  
{ 1r@v \#P  
if(sHeader.equals("Content-Length")) 9t=erhUr  
{ MjHeUf
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m0:8thZN  
break; z\fk?Tj<ro  
} 7FWf,IjcGY  
} {C 7=  
else ]RxNSr0e  
break; &:Q""e!  
} 1cUC>_%?  
} |%$d/<<PZ  
catch(IOException e){e.printStackTrace ();} l*h6JgU  
catch(Exception e){e.printStackTrace ();} A+?n=IHh  
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Utility.log(nFileLength); i2y?CI  
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i`
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return nFileLength; h$lY,7  
} \2W( >_z  
7m8L!t9  
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//保存下载信息（文件指针位置） wd u>3Ch"y  
private void write_nPos() )U8F6GIC&}  
{ |]Ockg[
  
try{ k/Cr ^J"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L[IjzxUv  
output.writeInt(nStartPos.length); y#r=^r]l)  
for(int i=0;i<nStartPos.length;i++) qD2<-E&M/  
{ <{e0i  
// output.writeLong(nPos); %R(j|a9z  
output.writeLong(fileSplitterFetch.nStartPos); | YvO$4=s  
output.writeLong(fileSplitterFetch.nEndPos); 7GKeqv  
} IWT
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output.close(); NJn~XCq  
} 594$X@!v  
catch(IOException e){e.printStackTrace ();} 6Bs_" P[  
catch(Exception e){e.printStackTrace ();} >4bOM@[]  
} dBCg$Rud&  
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}Dk_
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//读取保存的下载信息（文件指针位置） Jg^tr>I~  
private void read_nPos() SxMh '  
{ I#9A\.pO  
try{ g=a-zg9LX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ""TRLs!:M  
int nCount = input.readInt(); h%#@Xd>.  
nStartPos = new long[nCount]; v)BUt,A  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) %N>@( .  
{ _M{m6k(h  
nStartPos = input.readLong(); R(ay&f%E  
nEndPos = input.readLong(); 2N`Vx3  
} aNfgSo05@n  
input.close(); (n#  
} eDG=-a4  
catch(IOException e){e.printStackTrace ();} |)1"*`z  
catch(Exception e){e.printStackTrace ();} y=-d*E  
} ZO:{9vt=/  
>pz/wTOi  
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private void processErrorCode(int nErrorCode) J>x)J}:;  
{ :N(L7&<
 
System.err.println("Error Code : " + nErrorCode); 61CNEzQ  
} r0?`t!%V  
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B-JgXW.\0  
//停止文件下载 RDk{;VED{  
public void siteStop() wXfy,W  
{ >(*jL  
bStop = true; UIbVtJ  
for(int i=0;i<nStartPos.length;i++) (Z sdj  
fileSplitterFetch.splitterStop(); l0Y(9(M@  
0G;RMR':5  
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} t:$p8qR  
} v||8Q\d  
//负责部分文件的抓取 mii9eZ  
**FileSplitterFetch.java [BmondOx  
*/ DS-Kot(k(z  
package NetFox; <"aPoGda  
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#>[+6y]U!  
import java.io.*; v-4eN1OS  
import java.net.*; -,3Ka:  
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public class FileSplitterFetch extends Thread { \/lH]u\x  
v&p
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$:F]O$A  
String sURL; //File URL %]RzC`NZ  
long nStartPos; //File Snippet Start Position F71.%p7C8"  
long nEndPos; //File Snippet End Position Bglh}_X  
int nThreadID; //Thread's ID RwN*/Li  
boolean bDownOver = false; //Downing is over <d
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boolean bStop = false; //Stop identical !)KX?i[Q  
FileAccessI fileAccessI = null; //File Access interface 2A {k>TjQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L@9"6&  
{ bZ:w_z[3=  
this.sURL = sURL; hZ5h(CQ?"#  
this.nStartPos = nStart; fGY. +W_  
this.nEndPos = nEnd; &nTB^MF  
nThreadID = id; *_3+ DF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KGzBK:  
} y~Sh|2x8v  
.,<-lMC+  
;g7nG{  
public void run() ~~b[X\1  
{ 5k<qJ9  
while(nStartPos < nEndPos && !bStop) Yc+/="&z  
{ 9kQ~)4#  
,`)!K}2  
p7Gs  
try{ \KDOI7  
URL url = new URL(sURL); Z_cTuu0'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NA!;#!  
httpConnection.setRequestProperty("User-Agent","NetFox"); D 0\  
String sProperty = "bytes="+nStartPos+"-"; jvCk+n[  
httpConnection.setRequestProperty("RANGE",sProperty); UACWs3`s+  
Utility.log(sProperty); pX*Oc6.0mu  
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InputStream input = httpConnection.getInputStream(); >/eQjp?:  
//logResponseHead(httpConnection); @ 4j#X  
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byte[] b = new byte[1024]; rW
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int nRead; TBvv(_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4Ts5*_  
{ 83Bp_K2\  
nStartPos += fileAccessI.write(b,0,nRead); n\ZDI+X  
//if(nThreadID == 1) 9=K=gfZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (]0ZxWF  
} 5<Xq7|Jt  

&iId<.SiJ  
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Utility.log("Thread " + nThreadID + " is over!"); IH'DCY:  
bDownOver = true; >jq~5HN  
//nPos = fileAccessI.write (b,0,nRead); "#qyX[\  
} Ks{^R`Oau  
catch(Exception e){e.printStackTrace ();} M~zdcVTbH  
} 4JT9EKo
 
} K.dgQ-vn  
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//打印回应的头信息 `$fwLC3j  
public void logResponseHead(HttpURLConnection con) <pK
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{ k#w[GL|T  
for(int i=1;;i++) 3;>|*(cO  
{ :(!il?  
String header=con.getHeaderFieldKey(i); I.euuzBgA  
if(header!=null) e{>X2UNW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); { P&l`  
Utility.log(header+" : "+con.getHeaderField(header)); #,0%g1  
else a)`b;]+9  
break; 0' @^PzX  
} ~ubGx  
} )R<hYd  
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public void splitterStop() JD^(L~n]  
{ '@3hU|jO!  
bStop = true; Q!(C$&f  
} e3yBB*@  
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} o2He}t2o  
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/* tT ~}lW)Y  
**FileAccess.java [kDjht|$>  
*//文件访问(定位，写) >c|u|^3zt  
package NetFox; .Qn54tS0q  
import java.io.*; ,)@Q,EHN;  
3tMs613  
Ayadvi(@P  
public class FileAccessI implements Serializable{ "~jt0pp  
.#2YJ~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k`F$aQV9`  
RandomAccessFile oSavedFile; Q?B5@J  
long nPos; )F,H(LblH  
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public FileAccessI() throws IOException <iajtq<Z  
{ ek1YaE  
this("",0); s+gZnne  
} 4=9To|U*  
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public FileAccessI(String sName,long nPos) throws IOException BQ2EDy=}6  
{ cE '`W7&A  
oSavedFile = new RandomAccessFile(sName,"rw"); Y4sf
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this.nPos = nPos; x JQde4  
oSavedFile.seek(nPos); }eXzs_  
} =toqEm~  
j{?,nJdQ  
6kK\nZ$o$  
public synchronized int write(byte[] b,int nStart,int nLen) 0(iTnzx0  
{ 6.kX~$K  
int n = -1; RMMx6L|-:  
try{ *Em 9R  
oSavedFile.write(b,nStart,nLen); I83ZN]  
n = nLen; Uc/MPCqZ  
} 'j6PL;~c  
catch(IOException e) qsk8#  
{ *y9 iuJ}  
e.printStackTrace (); 9&q<6TZz  
} O,>1GKw"\  
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return n; JEL=,0J  
} DBANq\  
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} ,R5NKWo  
"K5n|{#  
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/* L:"i,K#P  
**SiteInfoBean.java J?&lpsB3_l  
*/ J)vP<.3:  
package NetFox; -g(&5._,ZW  
oqH811  
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public class SiteInfoBean { {|c <8  
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Adp:O"-H1o  
private String sSiteURL; //Site's URL 3U9]&7^  
private String sFilePath; //Saved File's Path ("<3w2Vlh  
private String sFileName; //Saved File's Name q$`{$RX  
private int nSplitter; //Count of Splited Downloading File ]#]|]>& <  
NWd%Za5K;  
&2C6q04b  
public SiteInfoBean() ~gQ$etPd  
{//nSplitter的缺省值为5 .<}(J#vC  
//default value of nSplitter is 5 z1X
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this("","","",5); kFZw"5hb  
} PXof-W  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {Hm0Q  
{
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sSiteURL= sURL; )
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sFilePath = sPath; v_?0|Ei[  
sFileName = sName; TkXD#%nFY  
this.nSplitter = nSpiltter; a@$U?=\e  
A rC4pT  
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} 7Gd)=Q{uur  
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public String getSSiteURL() "PK\;#[W|  
{ NXb_hF  
return sSiteURL; /( %Q  
} _\waA^ F  
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public void setSSiteURL(String value) p!BZTwP  
{ cf)2GoV>e  
sSiteURL = value; 0(\ybppx  
} S^'?sfq  
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public String getSFilePath() hn\<'|n  
{ fx(^}e  
return sFilePath; =$;i  
} 6
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;M}'\.  
public void setSFilePath(String value) d%VG@./xq  
{ VZBT'N  
sFilePath = value; H'|b$rP0@  
} %S
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public String getSFileName() >fRI^Q,  
{ :%cL(',Q  
return sFileName; ~`)`Ip  
} ( P|Ph  
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public void setSFileName(String value) F`KA^ZI  
{ ,DsqKXSU  
sFileName = value; rKEi1b  
} +>mbBu!7  
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public int getNSplitter() #1
2  
{ ]7" W(  
return nSplitter; 5W_u|z+/g  
} '7AlE!7%  
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public void setNSplitter(int nCount) A.tONPi  
{ S^0Po%
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nSplitter = nCount; aC:Sy^Tf  
} 5q?2?j/h  
} D#|+PG7  
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/* Si#I^aF`%  
**Utility.java KPO?eeT.WZ  
*/ ZYD
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package NetFox; a_Y*pOu  
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public class Utility { 1%~yb Q  
EUH&"8 L  
^_W+
 
public Utility() DZo7T!  
{ 0gdFXh$!e  
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h
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} Gq%q x4  
3\_ae2GW  
//线程睡眠 KP{|xQ>  
public static void sleep(int nSecond) B1dVHz#  
{ 7x`dEi<  
try{
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Thread.sleep(nSecond); w@w(AFV9/  
} i}teY{pyc  
catch(Exception e) |hBX"  
{ KW.*LoO  
e.printStackTrace (); v5STe`  
} 9}p>='  
} .?{rd3[ec  
-4ityS @  
//日志 ^uB9EP*P  
public static void log(String sMsg) ?m.WqNBH7  
{ S9/oBxGN  
System.err.println(sMsg); 8xs}neDg*  
} cojtQD
6  
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public static void log(int sMsg) gzfs9e  
{ Yd]y`J?#  
System.err.println(sMsg); ZC}'! $r7  
} zAT7^q^  
} qxS=8#-`(  
y+b4sFf  
^Ud1 ag!-  
/* ?d@3y<A,~  
**TestMethod.java `K -j  
*/ 2R9AYI  
package NetFox; +M4X r*  
k#mQLv  
)~/;Xl#b-  
public class TestMethod { g'2'K  
lAjP'(  
#[ZF'9x  
public TestMethod() k?r-%oJ7  
{ ///xx/weblogic60b2_win.exe hM}rf6B  
try{ j8Nl'"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4n6EkTa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D7q%rO|F'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g\9I&z~?  
fileFetch.start(); b4NUx)%ln  
} Axb,{X[6g  
catch(Exception e){e.printStackTrace ();} },r30`)Q  
kU uDA><1  
u,h,;'J  
} zadn`B#2  
50MdZ;R-3  
-+1_ 1!  
public static void main(String[] args) =W+ h.?  
{ !~X[qT  
new TestMethod(); J\7ukm"9  
} ,
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} hC1CISm.U  
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