http断点续传简单实现（java)

/* P#rwYPww\  
**SiteFileFetch.java 8m-jU 5u  
*/ M8S4D&vpD4  
package NetFox; fs>0{  
import java.io.*; lKH"PH7*_w  
import java.net.*; Gash3}+  
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public class SiteFileFetch extends Thread { D.R5-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Kq6m5A]z  
long[] nStartPos; //开始位置 ~iF*+\  
long[] nEndPos; //结束位置 p~Dm3^Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UxD1+\N6?  
long nFileLength; //文件长度 sOU_j4M{  
boolean bFirst = true; //是否第一次取文件 #BlH)Cv  
boolean bStop = false; //停止标志 @YW
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File tmpFile; //文件下载的临时信息 otX#}} +  
DataOutputStream output; //输出到文件的输出流 &v3r#$Hj[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D1#E&4   
public SiteFileFetch(SiteInfoBean bean) throws IOException ((;9%F:/$  
{ --",}%-  
siteInfoBean = bean; CcAsJX~_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  v+G}n\F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]WyV~Dzz<  
if(tmpFile.exists ()) b^hCm`2w*  
{ }[ux4cd8Y  
bFirst = false; ot(|t4^  
read_nPos(); LUS7-~:F  
} rw_&t>Ri;  
else '>'h
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{ EkWe6m  
nStartPos = new long[bean.getNSplitter()]; Qpf BM  
nEndPos = new long[bean.getNSplitter()]; U|U/B  
} ): Q5u6  
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} v`beql  
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public void run() ]2b" oHg  
{ kF
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//获得文件长度 SL@Vk(  
//分割文件 fVR ~PG0  
//实例FileSplitterFetch hTVN`9h7  
//启动FileSplitterFetch线程 >SfC '*1  
//等待子线程返回 j] M)i:n  
try{ ~R!(%j ]  
if(bFirst) O aF+Z@s  
{ 0SvPyf%A
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nFileLength = getFileSize(); >2$Ehw:K^  
if(nFileLength == -1) )m5<gp`  
{ y<3v/,Y  
System.err.println("File Length is not known!"); G/<{:R"  
} /:awPYGH<1  
else if(nFileLength == -2) #c/v2  
{ \4zvknk<  
System.err.println("File is not access!"); r]0o  
} ;}|.crMF  
else aoF>{Z4&B  
{ L)B?p!cdLT  
for(int i=0;i<nStartPos.length;i++) o L6[i'H|  
{ u$<FKp;I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @@ZcW<Y"  
} :MJBbrV ,  
for(int i=0;i<nEndPos.length-1;i++) / HaS.  
{ Kau*e8  
nEndPos = nStartPos[i+1]; hh:)"<[  
} WxO*{`T!  
nEndPos[nEndPos.length-1] = nFileLength;  ] mP-HFl  
} Q&M(wnl5  
} 1Rp|*>  
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y=
  
//启动子线程 &Lq @af#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O]{H2&k@  
for(int i=0;i<nStartPos.length;i++) X8;03EW;  
{ unD8h=Z2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o/=K:
5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #+ n &  
nStartPos,nEndPos,i); Hyee#fB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1egryp  
fileSplitterFetch.start(); 
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} 39~fP)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]]d@jj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {'r(P&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JmN;v|wF:c  
nEndPos = " + nFileLength); WNL3
+  
// fileSplitterFetch[nPos.length-1].start(); }[i35f[w  
y)(SS8
JR  
A9tQb:  
//等待子线程结束 \N"K^kR4  
//int count = 0; rt~X(S  
//是否结束while循环 YrZAy5\  
boolean breakWhile = false; cMK6  
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)]qFI"B7  
while(!bStop) c1:op@t  
{ G9VzVx#T#  
write_nPos();
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Utility.sleep(500); 
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breakWhile = true; ]/d2*#  
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for(int i=0;i<nStartPos.length;i++) hj4A&`2  
{ 9lA YCsX  
if(!fileSplitterFetch.bDownOver) ?hDEFW9&^x  
{ Ud{-H_m+  
breakWhile = false; luC',QJB  
break; 8,kbGlSD  
} #+_OyZ*  
} vZ|-VvG  
if(breakWhile) I;mtyS
 
break; 4] DmgOru%  
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//count++; \uanQ|Nu  
//if(count>4) F7"Ihb^l  
// siteStop(); Gl1`Nx0  
} J`"1
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System.err.println("文件下载结束！"); F ^E(AE  
} u)Y#&qA  
catch(Exception e){e.printStackTrace ();} 9`09.`U9[  
} &6}vvgz  
3:=XU9p)x  
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//获得文件长度 CQtd%'rt6  
public long getFileSize() 9sT?"(=  
{ Wa[~)A  
int nFileLength = -1; =BGc@:2  
try{ z,]fR  
URL url = new URL(siteInfoBean.getSSiteURL()); A#jiCIc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $B$=,^)3  
httpConnection.setRequestProperty("User-Agent","NetFox"); \sRRLDj%  
;#Mq=Fr-SG  
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int responseCode=httpConnection.getResponseCode(); EG9S? $  
if(responseCode>=400) c\;}ov+  
{ C %EQ9Iq6r  
processErrorCode(responseCode); ;j/ur\37  
return -2; //-2 represent access is error .vT'hu  
} ?94da4p  
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String sHeader; "[#jq5> :  
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for(int i=1;;i++) /pyKTZ|  
{ FAQ:0L$G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?T4%"0  
//Utility.log(in.readLine()); r_2  
sHeader=httpConnection.getHeaderFieldKey(i); YDQV,`S7  
if(sHeader!=null)
/?_{DMt  
{ ]AHi$Xx  
if(sHeader.equals("Content-Length")) Tzk8y7$[  
{ X2Lhb{ZHE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }]n&"=Zk-  
break; {{<o1{_H  
} !P:hf/l[B  
} qC3 rHT]  
else -<s?`Rnk  
break; T`WFY  
} pH"LZ7)DI0  
} qKSM*k~  
catch(IOException e){e.printStackTrace ();} '2.F-~  
catch(Exception e){e.printStackTrace ();} @Qx;J<{+g  
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Utility.log(nFileLength); ?29 KvT;#]  
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return nFileLength; dmF<J>[  
} c/x(v=LW  
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//保存下载信息（文件指针位置） n1cAI|ZE  
private void write_nPos() y'zEaL&SI@  
{ %9zcc)cP  
try{ m' aakq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G
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output.writeInt(nStartPos.length); I
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for(int i=0;i<nStartPos.length;i++) s*!2oj  
{ jf
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// output.writeLong(nPos); ".@SQgyb0  
output.writeLong(fileSplitterFetch.nStartPos); g`&pQ%|=  
output.writeLong(fileSplitterFetch.nEndPos); &Owt:R)9~  
} 5T;_k'qe  
output.close(); T+~~w'v0  
} 0[hl&7 Ab@  
catch(IOException e){e.printStackTrace ();} S`*al<m  
catch(Exception e){e.printStackTrace ();} 'Lm.`U  
} $9l3DJ  
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//读取保存的下载信息（文件指针位置） E|5gKp-wJ  
private void read_nPos() ]#*@<T*[  
{ ~ R*6w($  
try{ TY88PXW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \Xkx`C  
int nCount = input.readInt(); 2cmqtlW"  
nStartPos = new long[nCount]; APLu?wy7s5  
nEndPos = new long[nCount]; +ATN2 o  
for(int i=0;i<nStartPos.length;i++) RCmPZ  
{ wZOO#&X#r  
nStartPos = input.readLong(); ^iI^)  
nEndPos = input.readLong(); 5-C6;7%:  
} x/4lD}Pw]  
input.close(); %d?%^) u,  
} N.&K"J  
catch(IOException e){e.printStackTrace ();} w1GCjD*y  
catch(Exception e){e.printStackTrace ();} iYnw?4Y  
} Y&&Y:+ V  
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private void processErrorCode(int nErrorCode) yk#:.5H  
{ @E==~ b  
System.err.println("Error Code : " + nErrorCode); 2>H\arEstR  
} 1fC|_V(0  
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//停止文件下载 Np=*B_ @8  
public void siteStop() U5"F1CaW~  
{ @lmke>  
bStop = true; !W3Le$aL  
for(int i=0;i<nStartPos.length;i++) -bj1y2)n  
fileSplitterFetch.splitterStop(); fqr}tvMr=T  
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} HQE#O4  
} ,Tr12#D:  
//负责部分文件的抓取 $ &^ ,(z9  
**FileSplitterFetch.java yx}:Sgv%  
*/ lRO8}XSI  
package NetFox; i>rn!?b  
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import java.io.*; ioviJ7N% O  
import java.net.*;
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public class FileSplitterFetch extends Thread { a v`eA`)S  
*3k~%RM%?  
4,aBNuxWd  
String sURL; //File URL PuOo^pFhH  
long nStartPos; //File Snippet Start Position {#;6$dU;(  
long nEndPos; //File Snippet End Position cX&c%~  
int nThreadID; //Thread's ID cfj6I  
boolean bDownOver = false; //Downing is over T&S< 0  
boolean bStop = false; //Stop identical .oe,#1Qh{  
FileAccessI fileAccessI = null; //File Access interface +g.WO5A  
1/{:}9Z@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I@z{Gr  
{ -~aVt~{k/  
this.sURL = sURL; gWlmQl  
this.nStartPos = nStart; ]ny(l#Hu:  
this.nEndPos = nEnd; -\I0*L'$|\  
nThreadID = id; +fwq9I>L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uj]GBo=  
} ?Rwn1.Z  
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public void run() %v|,-B7Yx  
{ F(w>lWs;  
while(nStartPos < nEndPos && !bStop) 4s"HO/  
{ O-G@To3\  
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try{ RM`8P5i]sF  
URL url = new URL(sURL); 62zlO{ >rJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V]<dh|x  
httpConnection.setRequestProperty("User-Agent","NetFox"); U{R*WB b  
String sProperty = "bytes="+nStartPos+"-"; c'(]n]a%  
httpConnection.setRequestProperty("RANGE",sProperty); j[z\p~^  
Utility.log(sProperty); <D 5QlAN  
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InputStream input = httpConnection.getInputStream(); w"sRK  
//logResponseHead(httpConnection); Y# lE  
#?-W.  
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byte[] b = new byte[1024]; @-7K~in?^  
int nRead;
1X{A}9nA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Z$pR_dazU  
{ C qxP@  
nStartPos += fileAccessI.write(b,0,nRead); LCdc7  
//if(nThreadID == 1) *(HH71Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c]n4vhUa5  
} XRz.R/  
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Utility.log("Thread " + nThreadID + " is over!"); VJNPs6  
bDownOver = true; L,l+1`Jz  
//nPos = fileAccessI.write (b,0,nRead); Gm|QOuw  
} Jsw<,uTD  
catch(Exception e){e.printStackTrace ();} A1Zu^_y'  
} ZWr\v!4  
} @4Y>)wn&;  
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Y
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//打印回应的头信息 i&l$G55F  
public void logResponseHead(HttpURLConnection con) ZNx{7]=a  
{ Na`qAj}  
for(int i=1;;i++) R<wb8iir  
{ S=my;M-  
String header=con.getHeaderFieldKey(i); z1L.  
if(header!=null) <oeHZD_OR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T@z$g  
Utility.log(header+" : "+con.getHeaderField(header)); &d*9#?9  
else k!%HcU%J  
break; xWlB!r<}Gz  
} ]]]7"a  
} -x RsYYw  
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public void splitterStop() c#rbyx?5  
{ 7IvCMb&%R  
bStop = true; yRy9*r=  
} In 1.R$O  
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} E+Gea[c  
).&$pXj  
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/* &556;l  
**FileAccess.java ilNm\fQ.  
*//文件访问(定位，写) ~PV>3c3l=  
package NetFox; }%:?s6Ler  
import java.io.*; vWgh?h/ot  
R `'@$"  
Y /wvn8~C  
public class FileAccessI implements Serializable{ a'A0CQ
 
6)?TWr'Ke  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8pk5[=3Z  
RandomAccessFile oSavedFile; U?}Maf  
long nPos; +wio:==  
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public FileAccessI() throws IOException XM)|v|  
{ ,CvU#ab8$  
this("",0); 5Q^~Z},  
} 85X^T]zo  
5 )C~L]  
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public FileAccessI(String sName,long nPos) throws IOException hgh1G7A&  
{ 0zfrx-'zN  
oSavedFile = new RandomAccessFile(sName,"rw"); Le}q>>o;q  
this.nPos = nPos; H37Z\x
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oSavedFile.seek(nPos); ?Jma^ S  
} O/5W-u  
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public synchronized int write(byte[] b,int nStart,int nLen) ?/u&U\P  
{ xr=f9?%R  
int n = -1; ;3-ssF}k*  
try{ TLkkB09fvk  
oSavedFile.write(b,nStart,nLen); f8n'9HOw>  
n = nLen; x~mXtqg  
} %?cPqRHJ ~  
catch(IOException e) "JGaw_o  
{ bhgh ]{  
e.printStackTrace (); 8(+X0}  
} Psv-y  
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return n; "q%)we  
} SnXLjJe  
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} ,iHt*SZ,*  
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/* ?@u &3/&  
**SiteInfoBean.java !]`]67lC  
*/ 6tzn%
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package NetFox; O8lOr(|l  
SrKF\h%/+  
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public class SiteInfoBean { H
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private String sSiteURL; //Site's URL zZy>XHR H  
private String sFilePath; //Saved File's Path M\]E;C'"U  
private String sFileName; //Saved File's Name DnTM#i:  
private int nSplitter; //Count of Splited Downloading File [C&c;YNp  
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public SiteInfoBean() Hnaq+ _]  
{//nSplitter的缺省值为5 n[clYi@e  
//default value of nSplitter is 5 Fl O%OD  
this("","","",5); ?oF@q :W  
} 4x3`dvfp/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9hq7:  
{ 3)7'dM  
sSiteURL= sURL; 1n,JynJ  
sFilePath = sPath; 6-^+btl)#  
sFileName = sName; "3v%|  
this.nSplitter = nSpiltter; d,>l;
l  
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} .=NK^  
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public String getSSiteURL() `j2z=5  
{ 6m{3GKaW~  
return sSiteURL; _Ih~'Y Fd  
} abK/!m[q  
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public void setSSiteURL(String value) WT0U)x( m5  
{ 
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sSiteURL = value; B>'\g O\2  
} C2VZE~U+  
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public String getSFilePath() bySw#h_  
{ 8Ej2JMc  
return sFilePath; p&q&Fr-  
} )PwDP  
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3Y8%5/D5  
public void setSFilePath(String value) UR\*KR;yM  
{ jjwY{jV  
sFilePath = value; fu|I(^NV  
} e]5QqM7  
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I7}[%(~Sf/  
public String getSFileName() &2g1Oy~  
{ D]0#A|nF  
return sFileName; 7_|zMk.J*  
} 1,/oS&?E  
)i?wBxq'MA  
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public void setSFileName(String value) ?iq:Gf
  
{ %@IR7v~  
sFileName = value; c~Ha68  
} X-%*`XG'  
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Z$@Juv&>5^  
public int getNSplitter() @
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{ M^bujGD  
return nSplitter; +XQS -=  
} J"z8olV  
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APF-*/K?  
public void setNSplitter(int nCount) 1ptPey  
{ 7y60-6r  
nSplitter = nCount; y)=
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} D,R/abYZH  
} >Rr]e`3wG  
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/* ^y??pp<1J  
**Utility.java /2YI!U@A  
*/ -dza_{&+iZ  
package NetFox; b,!h[  
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*%MY. #  
public class Utility { GB{%4)%6  
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public Utility() $
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{ DQE.;0ld  
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} ;Neld #%J  
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//线程睡眠 qEywExdiu  
public static void sleep(int nSecond) J0{0B=d;  
{ Er%nSH^"  
try{ e\)PGjSI  
Thread.sleep(nSecond); tW 9vo-{+  
} /Jo*O=Lpo  
catch(Exception e) f):|Ad|  
{ O* 7"Q&  
e.printStackTrace (); -()CgtSR  
} AJj6@hi2P  
} p!HpqW  
tQ*5[F,fm  
//日志 QupCr/Hs  
public static void log(String sMsg) zEa3a  
{ cm-!6'`  
System.err.println(sMsg); 9V\5`QXu  
} &6!x;RB  
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public static void log(int sMsg) Bl(we/r  
{ w%`7,du|  
System.err.println(sMsg); ?a(ApD\  
} 4D0"Y#&G  
} 9CxU:
;3  
@UX'(W  
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/* {Z$Aw4a"d  
**TestMethod.java dMYDB  
*/ -cOLgrmp  
package NetFox; 2y,f  
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public class TestMethod { O$KLQ'0"n  
t}]=5)9<  
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public TestMethod() EQMn'>  
{ ///xx/weblogic60b2_win.exe %[5hTf  
try{ <kp?*xV]]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (Y:5u}*Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); cbNr
to9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <Knl6$B  
fileFetch.start(); PjDYdT[  
} h>q&X4-  
catch(Exception e){e.printStackTrace ();} }c$Zlb  
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} YG$Y4h" @"  
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public static void main(String[] args) 0)+F}SyyD  
{ gm(`SC?a  
new TestMethod(); j$,:cN  
} Qv|A^%Ub!  
} 7$Jb"s  
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