http断点续传简单实现（java)

/* - s{&_]A~  
**SiteFileFetch.java hsQ*ozv[)  
*/  ZLf(m35  
package NetFox; >{rD3X"d  
import java.io.*; b=L|GV@$  
import java.net.*; n
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public class SiteFileFetch extends Thread { %T;VS-f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c.>OpsF  
long[] nStartPos; //开始位置 _PP-'^ U  
long[] nEndPos; //结束位置 8p/&_<mnW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hs
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long nFileLength; //文件长度 5fp&!HnG  
boolean bFirst = true; //是否第一次取文件 =#%Vs>G  
boolean bStop = false; //停止标志 =jU#0FAO  
File tmpFile; //文件下载的临时信息 )M56vyo  
DataOutputStream output; //输出到文件的输出流 )Q|sW+AF  
)G#O#Yy
  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3Ea/)EB]  
public SiteFileFetch(SiteInfoBean bean) throws IOException BG]|iHi  
{ nv:VX{%  
siteInfoBean = bean; |4` ;G(ta  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =feVT2*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,pdf$) XB  
if(tmpFile.exists ()) n

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{ TF,([p*  
bFirst = false; C3K")BO!  
read_nPos(); 7|)K!  
} 8Urj;KkD  
else S;nlC  
{ ^Uik{x  
nStartPos = new long[bean.getNSplitter()]; C33RXt$X  
nEndPos = new long[bean.getNSplitter()]; ZM57(D  
} 0!1cHB/c  
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} #/hXcF  
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public void run() B+ZhQW  
{ buMST&  
//获得文件长度 bp P3#~ K  
//分割文件 |W|RX3D  
//实例FileSplitterFetch D}nRH@<`  
//启动FileSplitterFetch线程 9t&m\J >8;  
//等待子线程返回 Z.U8d(  
try{  ;W@  
if(bFirst) !q^2| %  
{ A$::|2~  
nFileLength = getFileSize(); h$$i@IO0  
if(nFileLength == -1) N6!9QIu~i  
{ PD:lI]:s  
System.err.println("File Length is not known!"); m=^ihQ  
} Q\2~^w1
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else if(nFileLength == -2) (:7Z-V2(  
{ oUN;u*  
System.err.println("File is not access!"); 1@^*tffL:  
} kAAD&t;w  
else kY~o3p<  
{ 6CNxb
  
for(int i=0;i<nStartPos.length;i++) Mqmy*m[
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{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); A_|X54}w&  
} Twk,R. O  
for(int i=0;i<nEndPos.length-1;i++) \U HI%1^  
{ xG,L*3c{o  
nEndPos = nStartPos[i+1]; OH`|aqN  
} zj#8@gbh+  
nEndPos[nEndPos.length-1] = nFileLength; -1]8f  
} #pWeMt'  
} jg(cpo d  
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//启动子线程 [CG*o>n&|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0G#s/u#  
for(int i=0;i<nStartPos.length;i++) 
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{ =XZd_v  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `4t*H>:y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5uL!Ae  
nStartPos,nEndPos,i); W JG8E7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0M;aTM  
fileSplitterFetch.start(); }r;#|=HR  
} zdN(r<m9"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V7,;N@FL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Uk0 0lPG.U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x:`"tJa  
nEndPos = " + nFileLength); $Rf)iW;h  
// fileSplitterFetch[nPos.length-1].start(); 3TNj*jo  
#Dl=K<I  
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//等待子线程结束 y-@{  
//int count = 0; m+pFU?<|  
//是否结束while循环 Y86mg7[U/  
boolean breakWhile = false; kD_616  
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while(!bStop) lQf38u||  
{ ~_|ZUb  
write_nPos(); ITBa ^P  
Utility.sleep(500); ?;CMsO*q  
breakWhile = true;  7D\:i1~  
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for(int i=0;i<nStartPos.length;i++) _K<Z  
{ Cg];UB}k  
if(!fileSplitterFetch.bDownOver) nT/Azg  
{ vptBDfzz  
breakWhile = false; _"S1>s)X?j  
break; G[a&r   
} \@GKVssw  
} W=!di3IA  
if(breakWhile) FYX"q-Z  
break; c"`CvQO64  
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//count++; DkeFDzQ5  
//if(count>4) E6s)J -a  
// siteStop(); DY8w\1g"  
} tZ_D.syBAc  
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System.err.println("文件下载结束！"); .%x%(olf  
} V-w{~  
catch(Exception e){e.printStackTrace ();} ;;7:l,vy  
} d\j[O9W>  
m 9.BU2.  
L IRdWGQ4  
//获得文件长度 jLF,R7t  
public long getFileSize() mD go@f  
{ wdQ%L4l  
int nFileLength = -1; E}8wnrxf  
try{ {9<c*0l  
URL url = new URL(siteInfoBean.getSSiteURL()); a0 8Wt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \jHIjFwQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); w ;xbQZ|+  
bTW# f$q:4  
RKO} W#?  
int responseCode=httpConnection.getResponseCode(); XywsjeI4  
if(responseCode>=400) l1ViUY&Z  
{ ^#)]ICV  
processErrorCode(responseCode); tQmuok4"d  
return -2; //-2 represent access is error 7s}Eq~  
} hmr2(f%U  
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String sHeader; sJ5Ws%q  
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for(int i=1;;i++) )6:1`&6  
{ Gq0`VHAn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tqwAS)v=  
//Utility.log(in.readLine()); b+e9Pi*\  
sHeader=httpConnection.getHeaderFieldKey(i); &^(4yw(~  
if(sHeader!=null) X@H/"B%u2  
{ {P!1VYs5  
if(sHeader.equals("Content-Length")) 4O:y ?D/e  
{ @"O|[%7e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gfly?)VnF  
break; c,FZ{O@  
} ytyB:# J  
} 9y{R_  
else EdC/]  
break; tM3Q;8gB!  
} {Xv0=P  
} GtpBd40"  
catch(IOException e){e.printStackTrace ();} r!y3VmJ'm  
catch(Exception e){e.printStackTrace ();} <7Ry"z6g;  
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Utility.log(nFileLength); :'X:cL  
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return nFileLength; 8\Kpc;zb  
} n'qWS/0U=  
 {B7${AE  
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//保存下载信息（文件指针位置） ,U?^u%  
private void write_nPos() A#8J6xcSrL  
{ bO+]1nZ.  
try{ <KBS ;t="1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i2l/y,UX  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) uo-1.[9ds  
{ XWag+K  
// output.writeLong(nPos); ^"] ]rZ)  
output.writeLong(fileSplitterFetch.nStartPos); e&-MP;kgW9  
output.writeLong(fileSplitterFetch.nEndPos); Fuy"JmeR  
} $nr=4'yZ  
output.close(); BI+x6S>d  
} P`AW8Y6o  
catch(IOException e){e.printStackTrace ();} =2e{T J/  
catch(Exception e){e.printStackTrace ();} C_S2a0?  
} 3wN{k\ns  
\Sv8c}8  
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//读取保存的下载信息（文件指针位置） <HH\VG\H6  
private void read_nPos() dheobD  
{ e5#?@}?  
try{ S9%ZeM+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @K1'Q!S*  
int nCount = input.readInt(); PC3?eS}  
nStartPos = new long[nCount]; YT}ZLx  
nEndPos = new long[nCount]; ToM1#]4  
for(int i=0;i<nStartPos.length;i++) g9@H4y6fe=  
{ BKKW3PT  
nStartPos = input.readLong(); <kKuis6h  
nEndPos = input.readLong(); pMd!Jl#(N  
} &X#6jTh+  
input.close();
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} 2hsRYh  
catch(IOException e){e.printStackTrace ();} uSUog+i  
catch(Exception e){e.printStackTrace ();} C2H2*"  
} bMB*9<c~  
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private void processErrorCode(int nErrorCode) >f70-D28  
{ 5O[\gd-  
System.err.println("Error Code : " + nErrorCode); #@L5yy2  
} \1<8'at  
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//停止文件下载 >!
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public void siteStop() 'Lh nl3  
{ 6'Q*SO;1gh  
bStop = true; lP*p7Y '  
for(int i=0;i<nStartPos.length;i++) Og7^7))  
fileSplitterFetch.splitterStop(); M}]4tAyT  
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} wizLA0W  
} eI98J"h%?  
//负责部分文件的抓取 ~DP5Qi  
**FileSplitterFetch.java IO7cRg'-F  
*/ >?[?W|k7V  
package NetFox; F0tcVdv  
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import java.io.*; -?w3j9kk>  
import java.net.*; '&/~Sh$%  
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public class FileSplitterFetch extends Thread { 2TgS )  
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String sURL; //File URL O Ke 9/._  
long nStartPos; //File Snippet Start Position JqV}$E"M2  
long nEndPos; //File Snippet End Position <[vsGUbc  
int nThreadID; //Thread's ID :9f 9Z7M  
boolean bDownOver = false; //Downing is over AjJ/t4<  
boolean bStop = false; //Stop identical kn+@)3W:*  
FileAccessI fileAccessI = null; //File Access interface |E&|6h1  
.EZ8yJj1Q  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?(M$r\\  
{ baGV]=j  
this.sURL = sURL; e5(c,,/  
this.nStartPos = nStart; .|0$?w  
this.nEndPos = nEnd; vI]V@il  
nThreadID = id; =R*IOJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ET(/h/r  
} cZ3A~dTOR  
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public void run() NfZC}  
{ .Hg{$SAC(w  
while(nStartPos < nEndPos && !bStop) g){gF(  
{ )}u?ftu\  
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try{ Zt}b}Bz  
URL url = new URL(sURL); 8S5Q{[!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J^!wk
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httpConnection.setRequestProperty("User-Agent","NetFox"); k ~4o`eA  
String sProperty = "bytes="+nStartPos+"-"; E {UhM q7  
httpConnection.setRequestProperty("RANGE",sProperty); f|Nkk*9$  
Utility.log(sProperty); XB a^ A  
}(oWXwFb&W  
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InputStream input = httpConnection.getInputStream(); \H 5t-w=  
//logResponseHead(httpConnection); h6?o)Q>N  
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byte[] b = new byte[1024]; l!": s:/'  
int nRead; -`$J& YU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }!"Cvu  
{ 89t"2|9 u  
nStartPos += fileAccessI.write(b,0,nRead); m~4ik1wq  
//if(nThreadID == 1) 8( Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `Om W#\  
} 5sSAH  
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Utility.log("Thread " + nThreadID + " is over!"); iFZ.a.NDc  
bDownOver = true; Ym6v4k!@O  
//nPos = fileAccessI.write (b,0,nRead); _-2;!L#/  
} j+e s  
catch(Exception e){e.printStackTrace ();} /T2 v`Li  
} bK{ VjXF  
} &'Xgf!x  
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JW"`i   
//打印回应的头信息 }GHCu
 
public void logResponseHead(HttpURLConnection con) ?5F;4oR2g  
{ 0IZF%`  
for(int i=1;;i++) %3. np  
{ dh1 N/[  
String header=con.getHeaderFieldKey(i); ED);2*qP}  
if(header!=null) A@-U#UvN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dj}|EW4  
Utility.log(header+" : "+con.getHeaderField(header)); UzW]kY[A<  
else =CO'LyG  
break; s[VYd:}se  
} c4zGQoeH:  
} olKM0K  
)u0/s'  
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public void splitterStop() /. H(&  
{ Oz
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bStop = true; 2`A[<S  
} 5W=Jn?y2  
m -0EcA/  
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} rC_saHo>#R  
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/* (iIzoEpb8W  
**FileAccess.java x:h)\%Dg<  
*//文件访问(定位，写) )`6OSB  
package NetFox; [.6bxK  
import java.io.*; B ]sVlbt  
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public class FileAccessI implements Serializable{ 4~8-^^  
#w8.aNU+]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 50a';!H  
RandomAccessFile oSavedFile; +|x%a2?x:  
long nPos; L(9AcP  
(*,R21<%  
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public FileAccessI() throws IOException ux,eY  
{ SLp nVD:'1  
this("",0); D(WV
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} 3{$>-d  
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public FileAccessI(String sName,long nPos) throws IOException Tt=;of{  
{ %a:T9v  
oSavedFile = new RandomAccessFile(sName,"rw"); @VyNe(U  
this.nPos = nPos; l}k'ZX4  
oSavedFile.seek(nPos); Z,"YMUl'  
} F?ps? e  
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public synchronized int write(byte[] b,int nStart,int nLen) B?Rkz  
{ :_`Yrx5  
int n = -1; n xR\tBv  
try{ +q+JOS]L  
oSavedFile.write(b,nStart,nLen); F&B E+b/#  
n = nLen; m=Mk@xfQ#  
} = uepg@J  
catch(IOException e) =@q,/FR-  
{ 4vND ~9d  
e.printStackTrace (); ^(@]5
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} c#>:U,j
 
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return n; 7#X`D  
} M 9NT%7Il  
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} 2izBB,# "  
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/* ?^LG>GgV  
**SiteInfoBean.java d`%7Pk  
*/ b!teSf  
package NetFox; .[1@wW&L  
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public class SiteInfoBean { 8dJ+Ei~M  
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private String sSiteURL; //Site's URL 9xE_Awlc85  
private String sFilePath; //Saved File's Path G({VK  
private String sFileName; //Saved File's Name TI0=nfj  
private int nSplitter; //Count of Splited Downloading File 4Lz[bI  
?FEh9l)d\  
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public SiteInfoBean() |KO[[4b ?+  
{//nSplitter的缺省值为5 m Ph=bG  
//default value of nSplitter is 5 "?FBbJ  
this("","","",5); 6&L;Sw#Dg  
} e AaS }g 0  
+}:2DXy@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '-$cvH7_  
{ Y"nz l]T  
sSiteURL= sURL; I]3!M`IMG  
sFilePath = sPath;
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sFileName = sName; @W~aoq6  
this.nSplitter = nSpiltter; W@zu
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} fN:FD`  
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public String getSSiteURL() ;lt8~ea  
{ uD[T l  
return sSiteURL; 09{s'  
} U!E}(9 tb
 
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public void setSSiteURL(String value) "|R75m,Id  
{ OI3j!L2f  
sSiteURL = value; =EU;%f  
} zZey
 
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[[  
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public String getSFilePath() NgF"1E  
{ bQ&%6'ck  
return sFilePath; pd.unEWwF  
}
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public void setSFilePath(String value) 'Asr,[]?  
{ @xBO[v  
sFilePath = value; <Q`3;ca^  
} nK
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VZtFgN$J  
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public String getSFileName() tCPK_Wws?Z  
{ "5?1S-Vl  
return sFileName; _j*I\  
} sD&V_ &i  
3Wx\Liw,  
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public void setSFileName(String value) #7}YSfm^6  
{ xr7M#n  
sFileName = value; a`?Vc}&  
} z+CX$
.Z  
<:mK&quf  
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public int getNSplitter() Q("4R  
{ `O;4b#!g  
return nSplitter; @Pi]kWW})  
} 2^w{Hcf  
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Z%=A[`5]  
public void setNSplitter(int nCount) 5w+&plIJ  
{ ;d_<6|*M  
nSplitter = nCount; <=w!:   
} WT3g31  
} X\i;j!;d  
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(Jk[%_b>_  
/* b)E<b{'W  
**Utility.java
o|#F@L3i  
*/ -(ST   
package NetFox; #hMkajG  
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public class Utility { cqW(9A|8  
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public Utility() Y]uVA`%"b  
{ 5r~hs6H  
v(Sh+p  
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} aygK$.wos  
W"CG&.  
//线程睡眠 PAxR?2m{  
public static void sleep(int nSecond) S2W@;XvV  
{ ^\Q%V
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try{ ZvO1=* J,  
Thread.sleep(nSecond); ~`B]G  
} W/CZ/Mc  
catch(Exception e) pK"Z9y&  
{ In+2~Jw/2!  
e.printStackTrace (); #^$_3AY  
} F2EX7Crj  
} ?32i
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2~B5?(g  
//日志 ugTnz$  
public static void log(String sMsg) \=xS?(v!  
{ RZ ?SiwE  
System.err.println(sMsg); |zd5P  
} w|*D{`O  
{LCKt/Z>P  
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public static void log(int sMsg) f|)~_JH  
{ vg_PMy\  
System.err.println(sMsg);  x\VP X  
} bka%W@Y%  
} Fdq5:v?k  
!C^>
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/* oEj$xm_}  
**TestMethod.java x-4d VKE*z  
*/ v$5D&Tv  
package NetFox; { 9\/aXPS  
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public class TestMethod { b^P\Q s*m  
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public TestMethod() i*A_Po  
{ ///xx/weblogic60b2_win.exe
GxC\Nj#  
try{ raU_Z[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "QD>:G;u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'm-5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @l5GBsLK  
fileFetch.start(); 9jNh%raG|  
} R|wS*xd,  
catch(Exception e){e.printStackTrace ();} GJHJ?^%  
f;Ijl0d@  
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} && PZ;  
7 `c!  
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public static void main(String[] args) W
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{ *O)i)["  
new TestMethod(); iWW >]3
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} /WK1(B:  
} P.1Z@HC  
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