http断点续传简单实现（java)

/* #fM`}Ij.A  
**SiteFileFetch.java {?7Uj  
*/ w_VP J  
package NetFox; 0JujesUw(  
import java.io.*; Zx>=t
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import java.net.*; "Z+k=~(  
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public class SiteFileFetch extends Thread { ?:9"X$XR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #,'kX
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long[] nStartPos; //开始位置 lH~[f  
long[] nEndPos; //结束位置 *lJxH8\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J]r^W)O  
long nFileLength; //文件长度 m.0*NW  
boolean bFirst = true; //是否第一次取文件 u:  
boolean bStop = false; //停止标志 |k00Z+O(  
File tmpFile; //文件下载的临时信息 z\4.Gm-  
DataOutputStream output; //输出到文件的输出流 ;q>ah!"k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <wHP2|<l*  
public SiteFileFetch(SiteInfoBean bean) throws IOException >/6 _ ^  
{ +LJ73 !  
siteInfoBean = bean; u)Whr@m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8H`[*|{'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;<4a*;IO  
if(tmpFile.exists ()) <%mRSv  
{ :b!s2n!u  
bFirst = false; *qpSXmOz  
read_nPos(); M D#jj3y  
} bvOq5Q6
 
else + >!;i6|  
{ b\,+f n  
nStartPos = new long[bean.getNSplitter()]; {Y1Ck5  
nEndPos = new long[bean.getNSplitter()]; 0PCGDLk8  
} \z)%$#I  
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} pTuS*MYz  
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public void run() ,`sv1xwd  
{ I( Mm?9F  
//获得文件长度 K@%].:  
//分割文件 z{r}~{{E  
//实例FileSplitterFetch HK%7g  
//启动FileSplitterFetch线程 Pc]HP  
//等待子线程返回 y<.5xq5_3  
try{ ez[Vm:2K  
if(bFirst) 4mbBmQV$#  
{ u$`a7Lp,n  
nFileLength = getFileSize(); lk=<A"^S  
if(nFileLength == -1) NX&_p!_V  
{ dQG=G%W  
System.err.println("File Length is not known!"); 2 ? 4!K.  
} \}G^\p6?M  
else if(nFileLength == -2) gI`m.EH}}N  
{ >.D4co>  
System.err.println("File is not access!"); u]G\H!WkQ  
} 3iU=c&P  
else Qv ?"b  
{ JsS-n'gF'  
for(int i=0;i<nStartPos.length;i++) ^kSqsT"  
{ 0IWf!Sk ]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BL4-7  
} _WbxH  
for(int i=0;i<nEndPos.length-1;i++) h>bx}$q  
{ (QiAisE  
nEndPos = nStartPos[i+1]; VS|2|n1<6  
} [.}oyz;}N  
nEndPos[nEndPos.length-1] = nFileLength; ;O#>Y  
} q0\6F^;M  
} Zgb!E]V[
 
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//启动子线程 OB}Ib]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bQ5\ ]5M  
for(int i=0;i<nStartPos.length;i++) Ht&YC<X  
{ &>}5jC.I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I*^Ta{j[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -DAlRz#d,  
nStartPos,nEndPos,i); 9Gz=lc[!7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =?`c=z3~i$  
fileSplitterFetch.start(); ]]Ufa
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} q75
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yoll?_k+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x$(f7?s] 1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8a"%0d#  
nEndPos = " + nFileLength); xe$_aBU  
// fileSplitterFetch[nPos.length-1].start(); ft Wv~Eh  
EB|}fz  
S5EK~#-L[  
//等待子线程结束 ?Ss!e$jf  
//int count = 0; ]J]h#ZH
x  
//是否结束while循环 PmM3]xVzd  
boolean breakWhile = false; 2b8L\$1q  
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while(!bStop) 3T0"" !Q  
{ j
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write_nPos(); t.C5+^+%  
Utility.sleep(500); '/%H3A#L  
breakWhile = true; {+b7sA3
 
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for(int i=0;i<nStartPos.length;i++) ,"79P/C  
{ XRQ4\bMA8  
if(!fileSplitterFetch.bDownOver) 1yY0dOoLG)  
{ S
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breakWhile = false; [=`q>|;pOv  
break; hK|Ul]qI  
} 8Xs8A.  
} I1&aM}y{G  
if(breakWhile) MnW+25=N  
break; k$}fWR  
#A8sLkY  
*}W_+qo"  
//count++; 8*a&Jl  
//if(count>4) `~q<N  
// siteStop(); r9G>jiw8  
} L9#g)tf 8T  
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System.err.println("文件下载结束！"); &PtJ$0%q  
} "@

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catch(Exception e){e.printStackTrace ();} IMONgFBS  
} kB%JNMF{A  
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}\k"n{!"  
//获得文件长度 A\5L 7  
public long getFileSize() C$)onk  
{ ,~W|]/b<q  
int nFileLength = -1; x'R`. !g3  
try{ Od)C&N=y  
URL url = new URL(siteInfoBean.getSSiteURL()); 9(wK@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wo=jskBrQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Ryp% Bn  
<1M-Ro?5k  
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int responseCode=httpConnection.getResponseCode(); U:_^#\p  
if(responseCode>=400) \1Em`nvOX  
{ r",GC]  
processErrorCode(responseCode); sCHJ&>m5-  
return -2; //-2 represent access is error "C`Ub  
} [}]Q?*_  
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String sHeader; 7Hu3>4<  
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for(int i=1;;i++) uM6+?A9@l  
{ k"w"hg&e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3=ymm^  
//Utility.log(in.readLine()); VY\&8n}e(  
sHeader=httpConnection.getHeaderFieldKey(i); SasJic2M  
if(sHeader!=null) R{T$[$6S  
{ V3j= Kf  
if(sHeader.equals("Content-Length")) 8)I^ t81
 
{ H$4:lH&(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0{R=9wcc  
break; '2^Q1{ :\  
} 6)Lk-D  
} :9 ^* ^T  
else kMd.h[X~  
break; k$^`{6l  
} 6!FQzFCZq  
} VP]%Hni]  
catch(IOException e){e.printStackTrace ();} B^9j@3Ux  
catch(Exception e){e.printStackTrace ();} czd~8WgOa  
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Utility.log(nFileLength); -3Vx76Y  
4{`{WI{  
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return nFileLength; ~qOa\#x_  
} V "h +L7T  
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//保存下载信息（文件指针位置） OI*Xt`  
private void write_nPos() 4r}8lpF_(  
{ D,FkB"ZZE  
try{ BThrO d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?5 7Sk+  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) D d</`iUq  
{ 9q[oa5INd  
// output.writeLong(nPos); w+CA1q<  
output.writeLong(fileSplitterFetch.nStartPos); W6/yn
 
output.writeLong(fileSplitterFetch.nEndPos); :6\qpex  
} ]?[fsdAQW  
output.close(); BF{Y"8u$  
} b1?'gn~  
catch(IOException e){e.printStackTrace ();} S|`o]?nc>  
catch(Exception e){e.printStackTrace ();} dlTt_.  
} )hfpwdQ  
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//读取保存的下载信息（文件指针位置） Z?m3~L9L2  
private void read_nPos() `+Q%oj#FF  
{ ]GQG~H^  
try{ Q$@I"V&G.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9zy!Fq  
int nCount = input.readInt(); ZExlGC  
nStartPos = new long[nCount]; TbW38\>.R  
nEndPos = new long[nCount]; jtc]>]6i  
for(int i=0;i<nStartPos.length;i++) NHZz _a=  
{ s,&Z=zt0R  
nStartPos = input.readLong(); JnM["Q=`  
nEndPos = input.readLong(); '(|ofJe!  
} _zi|  
input.close(); WEi2=3dV  
} 0Z{ZO*rK  
catch(IOException e){e.printStackTrace ();} ~FG]wNgS  
catch(Exception e){e.printStackTrace ();} :X (=z;B;N  
} G*P#]eO  
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}#  
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private void processErrorCode(int nErrorCode) |_@>*Vmg  
{ IB]l1<  
System.err.println("Error Code : " + nErrorCode); j+ 0I-p  
} VS8Rx.?  
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}?Ai87-{  
//停止文件下载
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public void siteStop() L0WN\|D  
{ b!5~7Ub.No  
bStop = true; XuM'_FN`A<  
for(int i=0;i<nStartPos.length;i++) 2!=f hN
 
fileSplitterFetch.splitterStop(); *YuF0Yt  
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*wB1,U{  
} QE`
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} e h?zNu2=  
//负责部分文件的抓取 P?of<i2E  
**FileSplitterFetch.java ExL0?FemWV  
*/ L>4"(  
package NetFox; -4{<=y?"a  
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import java.io.*; .jjG(L  
import java.net.*; JYbL?N  
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public class FileSplitterFetch extends Thread { %2V?,zY@  
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String sURL; //File URL KF!Yf\  
long nStartPos; //File Snippet Start Position Od,qbU4O  
long nEndPos; //File Snippet End Position _5Ct]vy  
int nThreadID; //Thread's ID [~c|mOk  
boolean bDownOver = false; //Downing is over &powy7rR  
boolean bStop = false; //Stop identical dk4CpN  
FileAccessI fileAccessI = null; //File Access interface "n5N[1bk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zw S F^  
{ XrGglBIV  
this.sURL = sURL; y(yHt=r  
this.nStartPos = nStart; O:{~urV  
this.nEndPos = nEnd; "CQa.%  
nThreadID = id; ['tY4$L(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wIaony  
} ,G?WAOy,  
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public void run() u.m[u)HQ  
{ czgO ;3-C  
while(nStartPos < nEndPos && !bStop) aP
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{ ' ;FnIZ  
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try{ B:S>wFE(.  
URL url = new URL(sURL); qUW! G&R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }"P|`"WW  
httpConnection.setRequestProperty("User-Agent","NetFox"); CMG&7(MR  
String sProperty = "bytes="+nStartPos+"-"; G+"t/?/  
httpConnection.setRequestProperty("RANGE",sProperty); L;NvcUFn  
Utility.log(sProperty); o!Ieb  
/}fHt^2H  
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InputStream input = httpConnection.getInputStream(); Ls$D$/:q?  
//logResponseHead(httpConnection); y@:h4u"3  
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byte[] b = new byte[1024];  vzs)[AD  
int nRead; n&;85IF1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .B]MpmpK  
{ {JO  
nStartPos += fileAccessI.write(b,0,nRead); 'qb E=  
//if(nThreadID == 1) FaQe_;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "fCu=@i  
} JPc+rfF  
*yt=_Q  
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Utility.log("Thread " + nThreadID + " is over!"); 7uS~MW  
bDownOver = true; NMa}{*sQ  
//nPos = fileAccessI.write (b,0,nRead); RK'\C\gMDu  
} XSe=s
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catch(Exception e){e.printStackTrace ();} J6s`'gFns  
} Pw7]r<Q  
} ,.83m%i  
jk; clwyz/  
B:;pvW]  
//打印回应的头信息 ?Wr+Q  
public void logResponseHead(HttpURLConnection con) h5{'Q$Erl  
{ 7a=gH2]&  
for(int i=1;;i++) /7nb,!~~l  
{ nA-.mWD_C  
String header=con.getHeaderFieldKey(i); SIF/-{i(X  
if(header!=null) hLd^ agX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Bw)/DM]  
Utility.log(header+" : "+con.getHeaderField(header)); "/*\1v9  
else 53;}Nt#R  
break; q1$N>;&  
} Cx(>RXVoJ,  
} UN;H+gNnN  
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public void splitterStop() n71r_S*  
{ V%7WUq  
bStop = true; knu,"<  
} =V,mtT  
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} b(eNmu  
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&=@IzmA  
/* \+oQd=K@  
**FileAccess.java 7{e 4c  
*//文件访问(定位，写) fIx+ILs  
package NetFox; 4x=v?g&  
import java.io.*; %B2'~|g  
$-OA'QwB]  
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public class FileAccessI implements Serializable{ j78i#}e  
,8S/t+H  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oA7tEu   
RandomAccessFile oSavedFile; (Z+.45{-  
long nPos;
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public FileAccessI() throws IOException g+8OekzB5  
{ "(3[+W{|  
this("",0);
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} zq3\}9  
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public FileAccessI(String sName,long nPos) throws IOException ]g#:KAqz  
{ 2 ~dE<}  
oSavedFile = new RandomAccessFile(sName,"rw"); >2Y=*K,:  
this.nPos = nPos; ^rB8? kt  
oSavedFile.seek(nPos); Z\(q@3C  
} AmUr.ofu  
<v"R.<  
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public synchronized int write(byte[] b,int nStart,int nLen) vOH4#  
{ \,'m</o~,  
int n = -1; 0G(/Wb"/  
try{ sbfuzpg]*  
oSavedFile.write(b,nStart,nLen); /m!BY}4W  
n = nLen; xS5vbJ  
} OW&!at  
catch(IOException e) dUD[e,?  
{
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e.printStackTrace (); xf'V{9*  
} "6("9"  
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return n; 3RUy,s  
}  >^O7  
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} [XN={  
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/* i}(LqcYU  
**SiteInfoBean.java Do9x XK  
*/ M.JA.I@XC  
package NetFox; `T1  
}czrj%6  
~\r*  
public class SiteInfoBean { HGl|-nW>  
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private String sSiteURL; //Site's URL hy9\57_#  
private String sFilePath; //Saved File's Path 1l9G[o *  
private String sFileName; //Saved File's Name [=C6U_vU  
private int nSplitter; //Count of Splited Downloading File v<k?Vu  
)J=!L\  
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public SiteInfoBean() I2XU(pYU  
{//nSplitter的缺省值为5 6]i-E>p3R  
//default value of nSplitter is 5 S*pGMuui  
this("","","",5); Xa[.3=bV?  
} y4yhF8E>;U  
^"E^zHM(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
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{ z>xmRs   
sSiteURL= sURL; 7K12 G!)  
sFilePath = sPath; cF*TotU_m  
sFileName = sName; :S]%6gb8G  
this.nSplitter = nSpiltter; c&6I[R  
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} Nd4f^Y  
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public String getSSiteURL() cs48*+m  
{ _r#Z}HK  
return sSiteURL; ZT*ydln  
} '(6z. toQ  
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public void setSSiteURL(String value) _IMW{  
{ e v}S+!|U  
sSiteURL = value; +SzU  
} 3qgS&js 7  
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public String getSFilePath() t mntp
 
{ wKh4|Ka  
return sFilePath; N>uRf0E>  
} O *C;Vqt  
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public void setSFilePath(String value)
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{ _{ue8kGt  
sFilePath = value; ,O5NLg-  
} ~i= _J3'  
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public String getSFileName() pp?D7S  
{ m[osg< CR_  
return sFileName; @)F)S7  
} eSn+B;  
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@3i\%R)n;  
public void setSFileName(String value) bG"~"ipn%  
{ +.8 \p5  
sFileName = value; rw[ph[\X  
} d7^}tM  
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public int getNSplitter() zC:ASt  
{ b)#hSjWO#  
return nSplitter; -:^U_FL8un  
} n)/z0n!\  
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public void setNSplitter(int nCount) &<g|gsG`  
{ Ju
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nSplitter = nCount; Rr$-tYy6  
} Oxnp0 s  
} FgnTGY}  
t^-d/yKt0w  
R+:yVi[F]U  
/* OF>mF~  
**Utility.java 2>9C-VL2  
*/ 1.JK33  
package NetFox; ZgJQ?S$D  
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public class Utility { lgAoJ[  
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h f)?1z4  
public Utility() 3Aip}<1  
{ *"2+B&Y  
s
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S>+|OCl";  
} hNiE\x  
^#-l q)  
//线程睡眠 A|[?#S((]  
public static void sleep(int nSecond) @u+]aI!`-  
{ <{p4V|:  
try{ 4KAZ ':  
Thread.sleep(nSecond); S\EyCi+  
}
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catch(Exception e) ITQA0PISL  
{ w(Ovr`o?9t  
e.printStackTrace (); )}R0Y=e  
} ~NgA  
} Ib!RD/  
+ J{IRyBc  
//日志 unzr0x {  
public static void log(String sMsg) `7Q<'oK  
{ )m+W j  
System.err.println(sMsg); F;EwQjTF  
} P:S.~Jq  
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g/_5unI}u  
public static void log(int sMsg) ~At7 +F[  
{ XW H5d-  
System.err.println(sMsg); QZwNw;$k*  
} hag$GX'2k
 
} c]-<vkpV  
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/* /<k/7TF`  
**TestMethod.java (/YHk`v2  
*/ <nf@U>wlw  
package NetFox; ]
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m~ABC#,2  
wm@@$  
public class TestMethod { .LZ?S"z$w  
h*
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public TestMethod() **0~K";\  
{ ///xx/weblogic60b2_win.exe @{e}4s?7od  
try{ 3%|&I:tI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GA)`-*.R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C=xa5Y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -ad{tJV|  
fileFetch.start(); :kV#y  
} }#+^{P3;  
catch(Exception e){e.printStackTrace ();} }&D WaO]J7  
{WS;dX4  
klYX7?  
} bWS&Yk(  
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public static void main(String[] args) ~P qM]^  
{ E=Bf1/c\  
new TestMethod(); RC"MdcD:]y  
} B mb0cFQ  
} "{xrL4BtC  
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