http断点续传简单实现（java)

/* E{0e5.{  
**SiteFileFetch.java 6f2?)jOW^N  
*/ _\=x A6!  
package NetFox; ;>uB$8<_7  
import java.io.*; B}S+/V` Y5  
import java.net.*; 3[j,d]\|  
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public class SiteFileFetch extends Thread { Iprt ZqiL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |}L=e.  
long[] nStartPos; //开始位置 L3w.<h  
long[] nEndPos; //结束位置 kebk f,`p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W[I$([  
long nFileLength; //文件长度 i=L 86Ks  
boolean bFirst = true; //是否第一次取文件 p5jR;nOZ%l  
boolean bStop = false; //停止标志 !E&l=*lM.  
File tmpFile; //文件下载的临时信息 ~/X8Hy!-  
DataOutputStream output; //输出到文件的输出流 vf zC2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >?1GJ5]\s  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^KdT,
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{ fF(AvMsO  
siteInfoBean = bean; ;vneeW4|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ep~+]7\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ber
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if(tmpFile.exists ()) @<3E`j'p  
{ DXG`%<ZMn  
bFirst = false; X~UL$S;  
read_nPos(); '<3h8\"  
} ,ss"
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else whYk"N  
{ wK0x\V6dJ  
nStartPos = new long[bean.getNSplitter()]; b}fC' h  
nEndPos = new long[bean.getNSplitter()]; BYu(a  
} /lbj!\~  
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} V@]SKbK}wN  
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public void run() -. o,bg  
{ Rz&`L8Bz  
//获得文件长度 ia3Q1 9r  
//分割文件 :1Nc6G  
//实例FileSplitterFetch %3*|Su%uC  
//启动FileSplitterFetch线程 \?oT.z5VG&  
//等待子线程返回 0J^Z)U>j  
try{ w+"E{#N  
if(bFirst) *Lxt{z`9  
{ c0Bqm  
nFileLength = getFileSize(); W**[:n+  
if(nFileLength == -1) *+zFsu4l  
{ =dH=3iCG  
System.err.println("File Length is not known!"); SHs [te[  
} T*mR9 8i  
else if(nFileLength == -2) XlD=<$Nk7  
{ !yT=*Cj4  
System.err.println("File is not access!"); p6NPWaBR  
} _h4]gZ  
else !?_CIt$p  
{ akk*f+TD`  
for(int i=0;i<nStartPos.length;i++) ?A;RTM  
{  ZB|s/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h<)ceD<,  
} qE3Ud:j  
for(int i=0;i<nEndPos.length-1;i++) ]zVQL_%,  
{ C[<{>fl)  
nEndPos = nStartPos[i+1]; 'zav%}b]L  
} p+<qI~  
nEndPos[nEndPos.length-1] = nFileLength; p2Gd6v.t  
} V dvj*I
 
}  ]Tb?z&  
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//启动子线程 Y@:l!4DI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cLp_\\  
for(int i=0;i<nStartPos.length;i++) 5=8v\q?)c  
{ G
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 50dN~(;p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IP$eJL[&D"  
nStartPos,nEndPos,i); JBA{i45x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xv Xci W  
fileSplitterFetch.start(); 8\9W:D@"x  
} kssRwe%>;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?*$uj(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {ZSAPq4)L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n|?sNM<J3  
nEndPos = " + nFileLength); zRmVV}b  
// fileSplitterFetch[nPos.length-1].start(); =$+0p3[r  
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n:B)
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//等待子线程结束 -W.-m2:1  
//int count = 0; *z6A ~U  
//是否结束while循环 Du +_dr^4  
boolean breakWhile = false; "=+i~N#Sc  
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while(!bStop) Dq%}({+  
{ )7!,_r  
write_nPos(); %QrOEs  
Utility.sleep(500); <$hv{a  
breakWhile = true; 4YI6&  
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for(int i=0;i<nStartPos.length;i++) \1&
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{ {>vgtkJ  
if(!fileSplitterFetch.bDownOver) @aN~97 H\  
{ ZvQZD=,F  
breakWhile = false; r_+!3   
break; uH?4d!G  
} N.+A-[7,W  
} 5#x[rr{^*  
if(breakWhile) 9>0OpgvC(  
break; KztQT9kY  
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//count++; nC !NZ  
//if(count>4) h8%QF'C  
// siteStop(); Cq7 u
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} 
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System.err.println("文件下载结束！"); g$mMH  
} bC"h7$3  
catch(Exception e){e.printStackTrace ();} +~YoP>  
} 2Mq
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//获得文件长度 J!RRG~  
public long getFileSize() Pzd!"Gl9  
{ A'uaR?  
int nFileLength = -1; /=l!F'  
try{ ooB9iNo^  
URL url = new URL(siteInfoBean.getSSiteURL()); O(-6Zqk8Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^8bc<c:P  
httpConnection.setRequestProperty("User-Agent","NetFox"); jj;TS%  
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int responseCode=httpConnection.getResponseCode(); G9xO>Xp^Al  
if(responseCode>=400) ZwY mR=  
{ js;YSg{m  
processErrorCode(responseCode); +A1*e+/b\  
return -2; //-2 represent access is error gBWr)R  
} =Ez@kTvOs  
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String sHeader; 9bRUN<  
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for(int i=1;;i++) nLwfPj  
{ p:$v,3:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eHKb`K7C.  
//Utility.log(in.readLine()); {/N8[?zML  
sHeader=httpConnection.getHeaderFieldKey(i); ge%QbU1J  
if(sHeader!=null) 3?`TEw~'  
{ IY[qWs  
if(sHeader.equals("Content-Length")) "Xwsu8~  
{ G(shZ=fq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'byTM?Sp{  
break; = =Q*|L-g  
} 9 `bLQd  
} P0_Ymn=&  
else 7BqP3T=&_  
break; }#M>CNi'PU  
} #H |p)2k  
} ?-o_]!*v0/  
catch(IOException e){e.printStackTrace ();} )h>dD  
catch(Exception e){e.printStackTrace ();} dblf,x  
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Utility.log(nFileLength); ^?\|2H  
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return nFileLength; UUbO\_&y  
} t>LSP$  
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//保存下载信息（文件指针位置） khT[  
private void write_nPos() m~W[,7NE0&  
{ #u+qV!4  
try{ 1^GRUbOU[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @q>#]8  
output.writeInt(nStartPos.length); b KIL@AI  
for(int i=0;i<nStartPos.length;i++) %qE"A6j  
{ 9C Ki$L  
// output.writeLong(nPos); n"}*C|(k  
output.writeLong(fileSplitterFetch.nStartPos); c68y\  
output.writeLong(fileSplitterFetch.nEndPos); 5A5t
 
}  @e\ @EW  
output.close(); "Y5 :{Kj  
} J{kS4v*J  
catch(IOException e){e.printStackTrace ();} c05-1  
catch(Exception e){e.printStackTrace ();} _*{Lha  
} vr?u=_%Z  
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//读取保存的下载信息（文件指针位置） G;pmR^  
private void read_nPos() IZ^:wIKo{  
{ 3QVUWhJ  
try{ +O8zVWr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BG.8 q4[  
int nCount = input.readInt(); c3c3T`B  
nStartPos = new long[nCount]; r58<A'#  
nEndPos = new long[nCount]; 3m-g-  
for(int i=0;i<nStartPos.length;i++) {%P2.:  
{ pXBh^  
nStartPos = input.readLong(); agruS'c g  
nEndPos = input.readLong(); +R;LHRS%  
} 
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input.close(); (~5]1S}F  
} umAO&S.+M  
catch(IOException e){e.printStackTrace ();} 8cMX
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catch(Exception e){e.printStackTrace ();} `)KGajB  
} ci:|x =  
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private void processErrorCode(int nErrorCode) *>Bew  
{ P
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System.err.println("Error Code : " + nErrorCode); HFFrS%  
} QuI!`/N)z  
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//停止文件下载 SdMLO6-  
public void siteStop() cH|J  
{ 7i02M~*uS  
bStop = true; 0
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for(int i=0;i<nStartPos.length;i++) Qgf|obrEi6  
fileSplitterFetch.splitterStop(); *A}td8(  
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} >zw@!1{1  
} *}Z  
//负责部分文件的抓取 w~pe?j_F$  
**FileSplitterFetch.java &t_TLV 8T  
*/ e}7!A  
package NetFox; dNqj|Vu  
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import java.io.*; -'WR9M?fq  
import java.net.*; 0(Z:QqpU$  
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public class FileSplitterFetch extends Thread { I3sf
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String sURL; //File URL ER[$TH&  
long nStartPos; //File Snippet Start Position z^4+Un  
long nEndPos; //File Snippet End Position ]]}iSw'  
int nThreadID; //Thread's ID Iue=\qUK^  
boolean bDownOver = false; //Downing is over $$Ibr]$5  
boolean bStop = false; //Stop identical yzL9Ic  
FileAccessI fileAccessI = null; //File Access interface R*k;4*1u  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rp:I&f$Hk/  
{ (sH4T>  
this.sURL = sURL; 9U3}_  
this.nStartPos = nStart; K9VP@[zbJ  
this.nEndPos = nEnd; UMFM.GI  
nThreadID = id; pa?AKj]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 87)/dHc  
} H+gB|  
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public void run() };Df ><  
{ 7`)RBhGB  
while(nStartPos < nEndPos && !bStop) gA1j'!\6l9  
{ \S?-[v*{  
8 K)GH:a  
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try{ 8-kR {9r  
URL url = new URL(sURL); BV/ ^S.~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m@L>6;*  
httpConnection.setRequestProperty("User-Agent","NetFox"); If'N0^'W  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); Z R~2Y?Wt9  
Utility.log(sProperty); 1sJz`+\  
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InputStream input = httpConnection.getInputStream(); L7xiq{t`Y  
//logResponseHead(httpConnection); 9j-;-`$S  
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byte[] b = new byte[1024]; B7[#z{8'#  
int nRead; A%&lW9z7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LUpkO  
{ 4[%_Bnv#AJ  
nStartPos += fileAccessI.write(b,0,nRead); ={
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//if(nThreadID == 1) .+u r+"i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QMX  
} #BH]`A J  
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Utility.log("Thread " + nThreadID + " is over!"); g@?R"  
bDownOver = true; 2sEG#/Y=  
//nPos = fileAccessI.write (b,0,nRead); }#=t%uZ/  
}  : ?Z9  
catch(Exception e){e.printStackTrace ();} dg+"G|nr  
} X%;4G^%ZI  
} dEX67rUj;  
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//打印回应的头信息 /%{CJ0Y  
public void logResponseHead(HttpURLConnection con) 0dD.xuor  
{ hX-^h2
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for(int i=1;;i++) rCA0c8  
{ ICG:4n(,  
String header=con.getHeaderFieldKey(i); pk;S"cnk  
if(header!=null) GQjU="+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m>!o Yy_  
Utility.log(header+" : "+con.getHeaderField(header)); :r:x|[3.  
else .~^A!t  
break; lD# yXLaC\  
} ~~p)_  
} ir|L@Jj,  
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public void splitterStop() HuN_$aP  
{ oIE3`\xS  
bStop = true; 9c0
  
} =dWqB&  
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} -y$<fu9 e  
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 2q9$5   
/* CSNz8 y  
**FileAccess.java {9Q**U`w  
*//文件访问(定位，写) z'gJy  
package NetFox; ]2@lyG#<<  
import java.io.*; d5=&:cF  
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public class FileAccessI implements Serializable{ 5pff}Ru`  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d@Wze[M?0  
RandomAccessFile oSavedFile; eG
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long nPos; "412w^5[T  
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public FileAccessI() throws IOException 4:s,e<Tc4v  
{ &C?4'e  
this("",0); br?pfs$U  
} VY=YI}E  
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public FileAccessI(String sName,long nPos) throws IOException `C^0YGO%  
{ 9R[PpE''  
oSavedFile = new RandomAccessFile(sName,"rw"); yRp&pUtb  
this.nPos = nPos; _0iV6Bj  
oSavedFile.seek(nPos); 3A! |M5  
} xxC2 h
3  
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public synchronized int write(byte[] b,int nStart,int nLen) YYe=
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{ -V'Y
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int n = -1; |#(y?! A^  
try{ w,<n5dMv  
oSavedFile.write(b,nStart,nLen); 7eF
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n = nLen; ^=gN >xP  
} _+Pz~_+kS  
catch(IOException e) Juk'eH2^s  
{ 5ne&6  
e.printStackTrace (); | `?J2WGe  
} fK^;?4  
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return n; 2LCOB&-Ww  
} owA.P-4  
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} pMf ?'l  
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/* ;[:IC^9fv  
**SiteInfoBean.java .k,,PuP
  
*/ *(Z\"o!  
package NetFox; GgtYO
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public class SiteInfoBean { wF*9%K'E  
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private String sSiteURL; //Site's URL v&sl_w/tn  
private String sFilePath; //Saved File's Path #9HX"<5  
private String sFileName; //Saved File's Name M>{*PHze0  
private int nSplitter; //Count of Splited Downloading File K d{o/R  
;O<-4$  
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public SiteInfoBean() ?YF2Uc8z%2  
{//nSplitter的缺省值为5 Z~;rp`P  
//default value of nSplitter is 5 IJ7wUZp"  
this("","","",5); Ir Y\Q)  
} ^SIA%S
3  
\ #la8,+9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MG^YT%f  
{ FA%V>&;`  
sSiteURL= sURL; UC.kI&A  
sFilePath = sPath; E<@N4%K_Q  
sFileName = sName; -'^:+FU  
this.nSplitter = nSpiltter; KppYe9?  
2g5jGe*0  
/^WOrMR  
} A~<cp)E  
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6$H`wDh#(&  
public String getSSiteURL() _Ec"[xW  
{ {"|la;*I  
return sSiteURL; D&OskM60  
} ({cWb:+r  
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public void setSSiteURL(String value) 3XDuo|(  
{ 1aPFpo!  
sSiteURL = value; AN)r(86L  
} u>*q
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public String getSFilePath() a>,Zp*V(  
{ 6!([Hu#= *  
return sFilePath; G[{Av5g mx  
} >1` '5A}s  
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public void setSFilePath(String value) 6d3YLb4M$i  
{ [JVUa2Sm  
sFilePath = value; Pv3 e*I(
(  
} \J{%xW>  
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4)d#dy::\  
public String getSFileName() .A<n2-
  
{ %XZdz=B  
return sFileName; 0I>[rxal  
} a]R1Fi0n  
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public void setSFileName(String value) >2< Jb!f&  
{ 0bR})}a+Yg  
sFileName = value; :FI4GR*?  
} XFvPc  
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public int getNSplitter() Qx[ nR/  
{ C.{z+  
return nSplitter; n0=[N'Tw3  
} >)iCKx
 
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public void setNSplitter(int nCount)
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{ tje  
nSplitter = nCount; A(qy>x-BI  
} e/
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} \g\,  
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*'ex>4^  
/* 5TcirVO82  
**Utility.java +J%9%DqF  
*/ Klk[h  
package NetFox; Fu#mMn0c  
$~2qEe.h  
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public class Utility { _#6ekl|%  
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public Utility() -<WQ>mrB&  
{ %wS5m#n  
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} 0p'=Vel{}  
c{s%kVOzg  
//线程睡眠 H-1y2AQ  
public static void sleep(int nSecond) 1t7S:IZ  
{ ?3:xR_VWZu  
try{ Z,m;eCLG]  
Thread.sleep(nSecond); S,TK;g
 
} .jC-&(R +  
catch(Exception e) ^ G(GjW8  
{ Q[N6#C:(4  
e.printStackTrace (); WD,iY_'7u^  
} gsp|?)]x  
} !<xeAo%8  
_,;|,  
//日志 QC*> qo  
public static void log(String sMsg) q!+m, !M  
{ t9B]V  
System.err.println(sMsg); U.HeIJ#  
} L|[0&u!  
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Y!|*`FII  
public static void log(int sMsg) |0$wRl+kN  
{ }^ j"@{~  
System.err.println(sMsg); Lz'05j3!  
} MH,vn</Uw  
} @ \(*pa  
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/* 5w+X   
**TestMethod.java LE:nmo  
*/ kmXaLt2Z  
package NetFox; .oFkx*Ln  
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@< @\CiM  
public class TestMethod { ^q0Ox&X  
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public TestMethod() T};fy+iq  
{ ///xx/weblogic60b2_win.exe E#=slj@  
try{ ;8 D31OT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?lYi![.o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7Bhi72&6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |?Z;tAF!  
fileFetch.start(); `|i[*+WC  
} GX+oA]  
catch(Exception e){e.printStackTrace ();}  D|[~Py  

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*VFUC:  
} |-c)OS3#D  
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Q!<b"8V]  
public static void main(String[] args) qUY QN2wG  
{ ]#N~r&hmQ  
new TestMethod(); _f8<t=R  
} v]tbs)x;h  
} QDg\GA8|  
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