http断点续传简单实现（java)

/* $tqr+1P  
**SiteFileFetch.java s}lp^Uh=  
*/ PfN[)s4F{R  
package NetFox; ':d9FzGKa  
import java.io.*; cGM?r}zJ  
import java.net.*; YZy%]i=1  
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public class SiteFileFetch extends Thread { /?%1;s:'  
*v#Z/RrrA  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VQ7A"&hh
 
long[] nStartPos; //开始位置 rI#,FZ  
long[] nEndPos; //结束位置 ^wlo;.8Y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cqG&n0zb  
long nFileLength; //文件长度 /0YO`])"  
boolean bFirst = true; //是否第一次取文件 :h8-y&;  
boolean bStop = false; //停止标志 Gp0yRT.  
File tmpFile; //文件下载的临时信息 cT|aQM@iW  
DataOutputStream output; //输出到文件的输出流 :>-&  
7-Mm+4O9  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }B
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public SiteFileFetch(SiteInfoBean bean) throws IOException !B/5@P  
{ MLvd6tIv,  
siteInfoBean = bean; kYZj^tR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HhB&vi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "IJ 9vXI  
if(tmpFile.exists ()) tjJi|  
{ av"dJm  
bFirst = false; +W+o~BE  
read_nPos(); Hto+
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} Gt$PBlq0  
else L2IY$+=M  
{ p5Wz.n.<'  
nStartPos = new long[bean.getNSplitter()]; b *Ca*!  
nEndPos = new long[bean.getNSplitter()]; |xFSGrC  
} }qg.Go  
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} /s Bs eI  
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public void run() &hnKBr(Lw  
{ Z#zXary5s  
//获得文件长度 5}4>vEn  
//分割文件 85rjM#~
  
//实例FileSplitterFetch vAqVs5 j  
//启动FileSplitterFetch线程 \ZtF,`Z  
//等待子线程返回 ?t [C?{'  
try{ i:2eJ.  
if(bFirst) @r
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{ cuQAXqXC@  
nFileLength = getFileSize(); lZJbQ=K{  
if(nFileLength == -1) zU2Mno  
{ M)G|K a  
System.err.println("File Length is not known!"); &~"e["gF=  
} c JOT{  
else if(nFileLength == -2) ,HwOMoP7  
{ !h70<Q^  
System.err.println("File is not access!"); X< 4f7;]O  
} |3C5"R3ZGO  
else W3A9uk6  
{ &Fh#otH_  
for(int i=0;i<nStartPos.length;i++) >JHQA1mX  
{ )\+1*R|H}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "H|hN  
} lNx:_g:SrZ  
for(int i=0;i<nEndPos.length-1;i++) Su
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{ |W*i'E  
nEndPos = nStartPos[i+1]; Vi>`g{\  
} <K
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nEndPos[nEndPos.length-1] = nFileLength; ~m&q@ms&  
} 8F/JOtkGMt  
} 64l(ru<  
;uaZp.<um&  
O0QK `F/)*  
//启动子线程 4||dc}I"E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \+>g"';f  
for(int i=0;i<nStartPos.length;i++) tr<0NV62>  
{ "bA8NQIP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~y>NJM>1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^v&)z,  
nStartPos,nEndPos,i); B qcFbY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); fBnlB_}e  
} u5A$VRMN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S3sxK:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '5}@#Mi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jd+U+8r  
nEndPos = " + nFileLength); @QAI 0ZY  
// fileSplitterFetch[nPos.length-1].start(); -op(26:W<  
UgD&tD0fp  
I2)#."=Ew  
//等待子线程结束 fcisD
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//int count = 0; )<vuv9=k\%  
//是否结束while循环 6$ ag<  
boolean breakWhile = false; ;` !j~  
?y2v?h"  
1{?5/F \ +  
while(!bStop) ^ ^k]2oG  
{ %ql2 XAY  
write_nPos();
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Utility.sleep(500); Y(C-o[-N  
breakWhile = true; v|wO qS  
.NT9dX  
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for(int i=0;i<nStartPos.length;i++) 5?-@}PL!Y  
{ {xCqz0  
if(!fileSplitterFetch.bDownOver) G'(8/os{  
{ HBcL1wfS  
breakWhile = false; ~ ":}Rs  
break; %Iv*u sXP  
} ~c${?uf   
} {J]x8
1}*;  
if(breakWhile) 7(B"3qF8|  
break; N.?)s.D(  
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e#s-MK-Q  
//count++; Bb*P);#.K  
//if(count>4) -}9>#<v  
// siteStop(); ~ }?*v}  
} X^)vZL?  
qORRpW
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System.err.println("文件下载结束！"); ObSRd$M  
} aLO'.5 ~^  
catch(Exception e){e.printStackTrace ();} Gk]6WLi  
} ?(>fB2^  
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//获得文件长度 ?VR:e7|tU  
public long getFileSize() 4x2,X`pe3  
{ P:fcbfH+  
int nFileLength = -1; Q$8K-5U%  
try{ hv#|dI=kZR  
URL url = new URL(siteInfoBean.getSSiteURL()); HB
, k}Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G$-[(eu-  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;CLOZ{  
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int responseCode=httpConnection.getResponseCode(); /eY}0q%  
if(responseCode>=400) UpS7>c7s  
{ ^(~%'f  
processErrorCode(responseCode); M&^Iun  
return -2; //-2 represent access is error 1XJLGMW,  
} Wph@LRB]  
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String sHeader; WFG`-8_e[I  
(X~JTH:e/  
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for(int i=1;;i++) vY2^*3\<D  
{ m.w.h^f$&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y8$I=  
//Utility.log(in.readLine()); Sq[LwJ  
sHeader=httpConnection.getHeaderFieldKey(i); 9_xJT^10  
if(sHeader!=null) J1"16Uu  
{ wA
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if(sHeader.equals("Content-Length")) WnL7 A:sZ  
{ uO5y{O2W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;-6   
break; kn&>4/')  
} 1`)e}
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} +{au$v}  
else I8Q!`KJ  
break; oe,yCdPs  
} '|@?R|i0  
} $$e"[g  
catch(IOException e){e.printStackTrace ();} lky5%H  
catch(Exception e){e.printStackTrace ();} ]4eIhj?  
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Utility.log(nFileLength); jP}Ix8vc=  
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return nFileLength; T.pc3+B8N  
} THY=8&x)  
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GGez!?E%  
//保存下载信息（文件指针位置） @@d6,=  
private void write_nPos() &*#Obv  
{ bDjm:G  
try{ 1h#e-Oyff  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L)X[$:  
output.writeInt(nStartPos.length); 7~!F3WT{  
for(int i=0;i<nStartPos.length;i++) nd,2EX<bE  
{ `&URd&ouJD  
// output.writeLong(nPos); P
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output.writeLong(fileSplitterFetch.nStartPos); |OBh:d_B]  
output.writeLong(fileSplitterFetch.nEndPos); DC(u,iW%6  
}  B6.9hf  
output.close(); \k
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} KZGy&u >`  
catch(IOException e){e.printStackTrace ();} rmJ`^6V  
catch(Exception e){e.printStackTrace ();} NM+(ss'  
} Sy"!Q%+|  
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//读取保存的下载信息（文件指针位置） y&6 pc  
private void read_nPos() Td5yRN! ?  
{ 2x!cblo  
try{ s2"<<P[q'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HpIWH*  
int nCount = input.readInt(); =fK6P6'B  
nStartPos = new long[nCount]; yR1v3D4E  
nEndPos = new long[nCount]; d-`z1'  
for(int i=0;i<nStartPos.length;i++) ::sk)  
{ 0SV4p.  
nStartPos = input.readLong(); "Pa  y2  
nEndPos = input.readLong(); 7mA:~-.u  
} r<5i  
input.close(); Y|cj&<o  
} gN.n_!  
catch(IOException e){e.printStackTrace ();} c' Q4Fzj0'  
catch(Exception e){e.printStackTrace ();} om2)Cd9~7  
} tL]T_]z  
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private void processErrorCode(int nErrorCode) @ RP?)*8}&  
{ @:t2mz:^i  
System.err.println("Error Code : " + nErrorCode); L~E|c/  
} X+QoO=02LR  
%+@<T<>J<k  
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//停止文件下载 6cXZ3;a  
public void siteStop() s9,Z}]Th  
{ t5k=ngA  
bStop = true; eI1C0Uz1  
for(int i=0;i<nStartPos.length;i++) <Yn-sH  
fileSplitterFetch.splitterStop(); GDYFhH7H  
5xhYOwQBo  
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} 6"yIk4u:  
} Y2$xlqQd"  
//负责部分文件的抓取 $S/EINc  
**FileSplitterFetch.java ZuT5}XxF  
*/ 7)*q@  
package NetFox; #|K5ma  
|O{kv}YZ  
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import java.io.*; '?1g_C QsS  
import java.net.*; $0*D7P^8  
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public class FileSplitterFetch extends Thread { r*UE>_3J  
`t>:i!s/  
RG:_:%@%}  
String sURL; //File URL #6@4c5{2=4  
long nStartPos; //File Snippet Start Position <3laNk  
long nEndPos; //File Snippet End Position ]/7#[  
int nThreadID; //Thread's ID > 1=].  
boolean bDownOver = false; //Downing is over t'[`"pp=  
boolean bStop = false; //Stop identical ~z'Y(qG  
FileAccessI fileAccessI = null; //File Access interface :{%~L4$HI  
(
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S3^(L   
{ |LirjC4  
this.sURL = sURL; H3+P;2{  
this.nStartPos = nStart; 465?,EpS  
this.nEndPos = nEnd; vF9fX
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nThreadID = id; lJt?0;gn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yM*_"z!L  
} Rbcu5.6  
H@'u$qr$:  
~:99 )AOM  
public void run() Bh;N:{&^Eu  
{ {bNVNG^  
while(nStartPos < nEndPos && !bStop) }(!3)k7*  
{ G%>M@nYUE  
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try{ Bw>)gSB5$k  
URL url = new URL(sURL); ?8YbTn1f)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ijmGk:L(  
httpConnection.setRequestProperty("User-Agent","NetFox"); _|7bpt
9  
String sProperty = "bytes="+nStartPos+"-"; wZt2%+$6m  
httpConnection.setRequestProperty("RANGE",sProperty); \hP.Q;"MtO  
Utility.log(sProperty); 2FQTu*p&B  
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InputStream input = httpConnection.getInputStream(); *fI\|%K  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; W4=A.2[q  
int nRead; JhvT+"~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tk+4noA  
{ Wa9yyc  
nStartPos += fileAccessI.write(b,0,nRead); W!JEl|]  
//if(nThreadID == 1) %v[KLMo'(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9>=S@hVMd  
} bT`et*]  
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Utility.log("Thread " + nThreadID + " is over!"); WQsu}_g5y  
bDownOver = true; .f`KP!p.  
//nPos = fileAccessI.write (b,0,nRead); "Iacs s0;  
} jXIVR'n(  
catch(Exception e){e.printStackTrace ();} { T?1v*.[  
} 8zQN[[#n  
} o@ @|4 F  
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//打印回应的头信息 )B"E+Q'h{7  
public void logResponseHead(HttpURLConnection con) tc{Qd&"(  
{ ut.tf \c  
for(int i=1;;i++) mp8Zb&Ggb  
{ =oTj3+7  
String header=con.getHeaderFieldKey(i); fDAT#nlyp  
if(header!=null) 6ipQx/IQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~-'-<-  
Utility.log(header+" : "+con.getHeaderField(header)); gSkY c{b  
else 3\K;y>NK  
break; e8{!Kjiz  
} oE)xL%*  
} %$=2tfR  
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public void splitterStop() sU/vXweky"  
{ NMESGNa)z  
bStop = true; 9]:F!d/  
} fvj  
)1f.=QZN^;  
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} ]j]
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/* TjOK8 t  
**FileAccess.java rq:sy=;  
*//文件访问(定位，写) `:Zgq+j&  
package NetFox; p,14'HS%@  
import java.io.*; I7W?}bR*6  
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(#+81 Dr  
public class FileAccessI implements Serializable{ y w:=$e5  
ON"p^o>/_?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AJ z 1  
RandomAccessFile oSavedFile; ps33&  
long nPos; Aa^w{D  
0@&/W-VXg  
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public FileAccessI() throws IOException tv5N wM  
{ <DhuY/o  
this("",0); "g5MltH  
} `bWc<
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/
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public FileAccessI(String sName,long nPos) throws IOException 8:K_S a%  
{ XpPcQIM*  
oSavedFile = new RandomAccessFile(sName,"rw"); v!AfIcEV  
this.nPos = nPos; G`f|#-}  
oSavedFile.seek(nPos); cbW=kQc_  
} qNUd "%S  
VH] <o0  
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public synchronized int write(byte[] b,int nStart,int nLen) +pe\9F  
{ K6,d{n  
int n = -1; AR c  
try{ %!R\-Vej  
oSavedFile.write(b,nStart,nLen); % -.V6}V  
n = nLen; f7Gs1{  
} 57EL&V%j  
catch(IOException e) X$eR RSW  
{ B[5<&  
e.printStackTrace (); 1*:BOoYx  
} SVPksr  
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return n; qAt#0  
} CHDt^(oa!B  
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} pv^:G;  
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/* ek d[|g  
**SiteInfoBean.java xu@xP5GB^  
*/ WA5.qw  
package NetFox; #-l+cu{  
=[0|qGzg  
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public class SiteInfoBean { tO3#kV\,  
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private String sSiteURL; //Site's URL 0|,Ij$  
private String sFilePath; //Saved File's Path 67U6`
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private String sFileName; //Saved File's Name lInf,Q7W  
private int nSplitter; //Count of Splited Downloading File $p*.[)  
{&J OO  
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public SiteInfoBean() L#fK ,r8  
{//nSplitter的缺省值为5 mNJCV8 <  
//default value of nSplitter is 5 6UU<:KH  
this("","","",5); I(j$^DA.  
} >|mZu)HIY;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xdMY2u  
{ z7pw~Tqlz  
sSiteURL= sURL; eKRE1
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sFilePath = sPath; biRkqc;  
sFileName = sName; ADA}_|O  
this.nSplitter = nSpiltter; W9S6 SO^\  
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(/ -90u  
} sYB2{w   
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public String getSSiteURL() y s[z[  
{ znAo]F9=J"  
return sSiteURL; 9}+X#ma.Nc  
} 27MwZz  
bnH:|-?q  
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public void setSSiteURL(String value) D#[<N  
{ lkJe7 +s  
sSiteURL = value; 5=1Ml50  
} V?~!Dp  
|Z8Eu0RSb  
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public String getSFilePath() p[}~Z|(  
{ Ao\Im(?  
return sFilePath; 8EU/}Ym  
} ,x?Jrcx~'C  
< Yc)F.:  
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public void setSFilePath(String value) {:=]J4]  
{ H;#C NB<e  
sFilePath = value; +K,T^<F;  
} 7tne/Yz  
szD9z{9"y  
Az/B/BLB  
public String getSFileName() g*!1S  
{ Bve',.xH  
return sFileName; eV"Uv3  
} FM|3'a-z  
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szXqJG8|  
public void setSFileName(String value) V5gr-^E  
{ _>_"cKS  
sFileName = value; 6NQ`IC  
} @h(Z;  
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public int getNSplitter() #k,.xMJ~  
{ cH707?p/I  
return nSplitter; Z:diM$Z?7  
} d+"
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public void setNSplitter(int nCount) 5x!rT&!G  
{ ):fu]s"  
nSplitter = nCount; <v?2p{U%  
} =Z..&H5i  
} x@D>JG  
"BIhd*K[~  
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/* bD?gwhAKA  
**Utility.java 8t
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*/ !v
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package NetFox; 6XnUs1O  
'r1X6?dJ  
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public class Utility { u
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T "#DhEM  
public Utility() ?QtM|e  
{ '@5x
=>  
5?|y%YH;R\  
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} 8"rK  
-![{Zb@  
//线程睡眠 V0n8fez b  
public static void sleep(int nSecond) $QwzL/a  
{ O2xqNQ`d  
try{ n^nQrRIp  
Thread.sleep(nSecond); L@J$kq
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} UJjtDV3@_g  
catch(Exception e) JURg=r]LI  
{ iF_u/#  
e.printStackTrace (); YoZd,} i  
} C~PP}|<~V  
} g!i45]6[Nw  
Z% ]LZ/O8  
//日志 w^:@g~  
public static void log(String sMsg) 5i'KGL  
{ "2 D{X  
System.err.println(sMsg); h;mOfF  
} 3@* ~>H  
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HUbXJsSP  
public static void log(int sMsg) M7#CMLy  
{ 6=x]20  
System.err.println(sMsg); hMgk+4*  
} Fxn=+Xgg  
} gx2v(1?S  
D'Uc?2X,&  
SCjVzvG$yg  
/* 2o7o~r  
**TestMethod.java 
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*/ %Rf{v5  
package NetFox; 4-9cp=\PE  
#IeG/t(  
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public class TestMethod { p*JP='p  
^c"\%!w"O  
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public TestMethod() |T-Ytuy8  
{ ///xx/weblogic60b2_win.exe }S%}%1pG7  
try{ ES#q/yab5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (e9hp2m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y 2^y73&k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7w\!3pv  
fileFetch.start(); (~(FQ:L%U  
} swMR+F#u*  
catch(Exception e){e.printStackTrace ();} S<5.}cR  
 h}}7_I9  
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} [P]M)vJ**  
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public static void main(String[] args) #XNURj  
{ "*KOU2}
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new TestMethod(); knWI7  
} #t VGqf  
} RG/P]  
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