http断点续传简单实现（java)

/* 3J}/<
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**SiteFileFetch.java 9jJ:T$}  
*/ }>yQ!3/i  
package NetFox; 92D :!C  
import java.io.*; lEC91:Jyt  
import java.net.*; Ih_=yk  
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public class SiteFileFetch extends Thread { +5N09$f;R  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rPx:o}&<  
long[] nStartPos; //开始位置 oTb4T=  
long[] nEndPos; //结束位置 f-5}`)`.+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yv(\5)XF  
long nFileLength; //文件长度 '/GZ/$a_l  
boolean bFirst = true; //是否第一次取文件 0czEA  
boolean bStop = false; //停止标志 BDcA_=^R&  
File tmpFile; //文件下载的临时信息 h,x'-]q  
DataOutputStream output; //输出到文件的输出流 O[5u6heNMr  
JL=s=9N;3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8z`Ne(h;  
public SiteFileFetch(SiteInfoBean bean) throws IOException df8aM<&m3  
{ vq8&IL  
siteInfoBean = bean; X8~gLdv8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I,7n-G_'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oL
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if(tmpFile.exists ()) v"V?  
{ pKhV<MFB  
bFirst = false; 9;L50q>s  
read_nPos(); ~PA6e+gmL  
} *3h!&.zm  
else .]LP327u  
{ 9V?:!%J  
nStartPos = new long[bean.getNSplitter()]; ,K8(D<{  
nEndPos = new long[bean.getNSplitter()]; /rzZU}3[  
} yr q){W  
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} A08{]E#v>  
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public void run() Vbp`Rm1?  
{ !^IAn  
//获得文件长度 o]WG8Mo-  
//分割文件 dL|*#e  
//实例FileSplitterFetch N6uKFQL:{  
//启动FileSplitterFetch线程
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//等待子线程返回 (E<QA  
try{ /u pDbP.O  
if(bFirst) h%!N!\  
{ YnwP\Arfq  
nFileLength = getFileSize(); r1AG1Y  
if(nFileLength == -1) `t Zw(Z=h  
{ }Oe9Zq  
System.err.println("File Length is not known!"); !~a1xI~s  
} ^<v]
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else if(nFileLength == -2) S1E=EVG  
{ V"W)u#4,  
System.err.println("File is not access!"); *S\/l-D  
} :'K%&e?7s  
else $#HUxwx4  
{ Sj9NhtF]f  
for(int i=0;i<nStartPos.length;i++) M|\C@,F]8  
{ hgI;^ia  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |C3~Q{A  
} {on+ ;,  
for(int i=0;i<nEndPos.length-1;i++) Jsw%.<  
{ t.6gyrV7><  
nEndPos = nStartPos[i+1]; N-<m/RS  
} 3PRK.vf  
nEndPos[nEndPos.length-1] = nFileLength; x L]Z3"p%  
} 8L,i}hIo.  
} &J}w_BFww  
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//启动子线程 Cl'3I%$8K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )+v'@]r  
for(int i=0;i<nStartPos.length;i++) {,
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{ ;&U! g&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1`l10fqU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WoX,F1o  
nStartPos,nEndPos,i); ~JSa]6:_+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1xt N3{c  
fileSplitterFetch.start(); ZY{zFg9  
} r^$WX@ t&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $ZfoJR]%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :Tn1]a)f6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c(!8L\69V}  
nEndPos = " + nFileLength); EP}NT)z,{  
// fileSplitterFetch[nPos.length-1].start(); 2` j
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//等待子线程结束 )ZQML0}P;  
//int count = 0; D$/*Z5Z)]  
//是否结束while循环 h;Se.{  
boolean breakWhile = false; AZ& ]@Ao  
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while(!bStop) HzD=F
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{ ~@N0$S  
write_nPos(); RlnJl
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Utility.sleep(500); .qG*$W2f  
breakWhile = true; )1 =|\  
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for(int i=0;i<nStartPos.length;i++) 3FpSo+  
{ {Wh7>*p{3  
if(!fileSplitterFetch.bDownOver) 7(1UXtT  
{ Q2HULz{
 
breakWhile = false; U8s&5~IPn  
break;
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} HE>sZ;  
} /;\{zA$uC=  
if(breakWhile) Y
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break; *m9,_~t  
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//count++; s2M|ni=  
//if(count>4) R8YA"(j!L  
// siteStop(); h!UB#-  
} L2m~ GnP|?  
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System.err.println("文件下载结束！"); 2*9rhOK*  
} yHt `kb2  
catch(Exception e){e.printStackTrace ();} nlaeo"]  
} cri.kr9Y  
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{  
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//获得文件长度 hY-;Vh0J  
public long getFileSize() SFRQpQ06  
{  LAfv1  
int nFileLength = -1; c DO<z  
try{ dLIZ)16&  
URL url = new URL(siteInfoBean.getSSiteURL()); -L)b;0%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0'O*Y ]h+  
httpConnection.setRequestProperty("User-Agent","NetFox"); .P>-Fh,_p  

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int responseCode=httpConnection.getResponseCode(); dJYQdo^X  
if(responseCode>=400) Bm&%N?9  
{ \"^.>+  
processErrorCode(responseCode); {^qp
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return -2; //-2 represent access is error __N#Y/e ]  
} 5\|u] ~b  
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String sHeader; ,}hJ)  
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for(int i=1;;i++) G,6Zy-Y9  
{ 9X6l`bo'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F"*.Qq  
//Utility.log(in.readLine()); dDoKmuY>5  
sHeader=httpConnection.getHeaderFieldKey(i); S0uEz;cE  
if(sHeader!=null) !p#+I=  
{ F4%vEn\!  
if(sHeader.equals("Content-Length")) j/+e5.EX/  
{ jaq`A'o5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WnLMa|e  
break; [~_()i=Y  
} hRWRXC9  
} DRU
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else rBY{&JhS  
break; |K
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} j(SBpM  
} uqMe%  
catch(IOException e){e.printStackTrace ();} hR1n@/nh  
catch(Exception e){e.printStackTrace ();} @<W^/D1#L  
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;  
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Utility.log(nFileLength); *MBu5 +u%e  
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return nFileLength; 4v("qNw#  
} "\l O1D  
RN0=jo!58  
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//保存下载信息（文件指针位置） <#r/4a"V  
private void write_nPos() MPg"n-g*  
{ ao(l
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try{ CS<,qvLpL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }F~4+4B^  
output.writeInt(nStartPos.length); mm,be.  
for(int i=0;i<nStartPos.length;i++) ZXR#t?D  
{ `
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// output.writeLong(nPos); lIlmXjL0  
output.writeLong(fileSplitterFetch.nStartPos); ^
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output.writeLong(fileSplitterFetch.nEndPos); ].C4RH  
} !u;r<:g!  
output.close(); zu@5,AH  
} t@(`24  
catch(IOException e){e.printStackTrace ();} `0qBuE_^h  
catch(Exception e){e.printStackTrace ();} Pb(XR+  
} UD@u hL  
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;F:~HrxT}  
//读取保存的下载信息（文件指针位置） =gjq@N]lAW  
private void read_nPos() M_Qv{   
{ J0eJRs  
try{ ,GH;jw)P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >){"x(4`  
int nCount = input.readInt(); :GaK.W q  
nStartPos = new long[nCount]; iO,_0Y4  
nEndPos = new long[nCount]; pDg_^
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for(int i=0;i<nStartPos.length;i++) 8'Y7lOXS  
{ ]U8VU  
nStartPos = input.readLong(); U0Y;*
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nEndPos = input.readLong(); .<Lbv5m  
} ?pAO?5Z:}  
input.close(); =(^-s Jk  
} ]S=AO/'  
catch(IOException e){e.printStackTrace ();} 0Ek+ }`  
catch(Exception e){e.printStackTrace ();} /s\_"p  
} 2unaK<1s  
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private void processErrorCode(int nErrorCode) 'K9{xI@N  
{ 69o,T
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System.err.println("Error Code : " + nErrorCode); PU6Sa-fQ2,  
} APC,p,"  
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//停止文件下载 q*^F"D:?k  
public void siteStop() w!=Fi  
{ p? dXs^ c  
bStop = true; *+-L`b{SX  
for(int i=0;i<nStartPos.length;i++) TC=djC4$/  
fileSplitterFetch.splitterStop(); o?Wp[{K  
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} %L\buwjy$  
} 6^oQ8unmS  
//负责部分文件的抓取 xgX"5Czvv`  
**FileSplitterFetch.java nS53mLU)  
*/ 7HpfHqJ7  
package NetFox; NiCH$+c\  
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import java.io.*; huu v`$~y  
import java.net.*; *7ggw[~  
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public class FileSplitterFetch extends Thread { G9/5KW}-  
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String sURL; //File URL D?v)Xqw=  
long nStartPos; //File Snippet Start Position Q bg,q  
long nEndPos; //File Snippet End Position $8{|25 *E  
int nThreadID; //Thread's ID QEavb
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boolean bDownOver = false; //Downing is over @-~ )M_  
boolean bStop = false; //Stop identical Q UQ"2oC  
FileAccessI fileAccessI = null; //File Access interface m5G9 B-\?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #9{9T"ed  
{ p;GT[Ds^  
this.sURL = sURL; d"1DE  
this.nStartPos = nStart; 4@qKML  
this.nEndPos = nEnd; C;T:'Uws  
nThreadID = id; =*AAXNs@3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y}fF<qih'>  
} yN0!uzdW*  
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public void run() c\n&Z'vK  
{ V>{G$(v$  
while(nStartPos < nEndPos && !bStop) Bc/'LI.%  
{ M<A*{@4$w&  
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try{ A?Dg
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URL url = new URL(sURL); &nc0stuL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cmzu @zq  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6O`s&T,t  
String sProperty = "bytes="+nStartPos+"-"; D['z/r6F  
httpConnection.setRequestProperty("RANGE",sProperty); SG&VZY  
Utility.log(sProperty); yU-^w^4  
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InputStream input = httpConnection.getInputStream(); !Od?69W, $  
//logResponseHead(httpConnection); Qg7rkRia  
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byte[] b = new byte[1024]; pzo9?/-  
int nRead; 2\$P&L a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CO
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{ PY4RwN  
nStartPos += fileAccessI.write(b,0,nRead); ad\?@>[I  
//if(nThreadID == 1) 2 kOFyD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -:hiLZJ7-  
} n~1'M/wh  
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Utility.log("Thread " + nThreadID + " is over!"); ')d&:K*M  
bDownOver = true; NF}QQwG3  
//nPos = fileAccessI.write (b,0,nRead); q(i^sE[y  
} P9Gjsu #  
catch(Exception e){e.printStackTrace ();} &B^zu+J  
} yqy5i{Y
 
} )yV|vn  
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//打印回应的头信息 }Htnhom0n  
public void logResponseHead(HttpURLConnection con) |Ef\B]Ns  
{ n21Pfig  
for(int i=1;;i++) s`j QX\{  
{ x[mxp/ /P  
String header=con.getHeaderFieldKey(i); X{n7)kgL  
if(header!=null) DcNQ2Zz?%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b7 pD#v  
Utility.log(header+" : "+con.getHeaderField(header)); X5@SLkJ-`  
else ^w0V{qF{  
break; 61Z#;2]  
} (M1HNIM;(  
}
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public void splitterStop() ")/TbTVu  
{ hX-([
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bStop = true; vv2N;/;I  
} y_^w|  
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} Lx{bR=  
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/* ]=s!cfu  
**FileAccess.java o/EN3J  
*//文件访问(定位，写) GM.2bA(y  
package NetFox; h8b*=oq  
import java.io.*; s6#@S4^=\  
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public class FileAccessI implements Serializable{ 16iymiLz&  
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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 <b-BJ2],k  
RandomAccessFile oSavedFile; "6T: &>  
long nPos; 5ryzAB O\2  
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@S/PB[%S  
public FileAccessI() throws IOException K!X>k

 
{ s m42  
this("",0); #q;hX;Va  
} wzw`9^B  
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public FileAccessI(String sName,long nPos) throws IOException ;z6Gk&?  
{ JvA6kw,  
oSavedFile = new RandomAccessFile(sName,"rw"); omxBd#;F$  
this.nPos = nPos; T&?0hSYt  
oSavedFile.seek(nPos); E$$pO.\  
} NDG3mCl  
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public synchronized int write(byte[] b,int nStart,int nLen) %ZNp  
{ -1tdyCez  
int n = -1; OD,"8JF  
try{ |!r.p_Zt  
oSavedFile.write(b,nStart,nLen); N=qe*Rlf  
n = nLen; xS~OAcxg  
} (BtavE  
catch(IOException e) 5lp L$  
{ L*ZC` .h  
e.printStackTrace (); {x{/{{wzv  
} Yp8~wdm  
9NH"Ik*  
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return n; )P6n,\  
}
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}
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/* L  lP  
**SiteInfoBean.java Qm|Q0u  
*/ '4PAH2&n  
package NetFox; ,&S^Ryc  
U @Il:\I  
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public class SiteInfoBean { Mr}]P(4h  
)" H$1  
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private String sSiteURL; //Site's URL Nw'3gJ:
 
private String sFilePath; //Saved File's Path j@0/\:1(U  
private String sFileName; //Saved File's Name \NYtxGV[Z  
private int nSplitter; //Count of Splited Downloading File P#o/S4  
!Jo3>!,j  
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public SiteInfoBean() {~*aXu3  
{//nSplitter的缺省值为5 ;H#'9p,2  
//default value of nSplitter is 5 2 }QD>  
this("","","",5); 2#4_/5(j*  
} a8T<f/qW k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0B(<I?a/  
{ myTz  
sSiteURL= sURL; NIeKS_ +  
sFilePath = sPath; !HA[:-JCz  
sFileName = sName; |>(@n{  
this.nSplitter = nSpiltter; I*e85wef  
G Q&9b_  
r`]&{0}23  
} K 7)1wiEj  
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public String getSSiteURL() QN[-XQ>Xt  
{ )hH9VGZq(  
return sSiteURL; GyV3]Qqj  
} !F0MLvdX7^  
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public void setSSiteURL(String value) qC9$xIWq  
{ ^/K\a ,  
sSiteURL = value; j(
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} 9Vx2VjK2'  
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public String getSFilePath() !FweXFl  
{ %H:uE*WZ  
return sFilePath; qvz2u]IOw  
} Wjt1NfS&  
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6  
public void setSFilePath(String value) ?45kN=%*s  
{ ScrEtN  
sFilePath = value;
! /Z{uy  
} = GirUW D  
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public String getSFileName() !j8h$+:K  
{ N9r}nqCN  
return sFileName; :+ef|,:`/  
} lkf(t&vL2  
.gNWDk0$Y  
]%IcUd}  
public void setSFileName(String value) :ho)3kB  
{ @sly-2{e1  
sFileName = value; D'aq^T'  
} ~LPxVYhK  
:.['e
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public int getNSplitter() $ WAFr  
{ bkkhx,Oi[G  
return nSplitter; |w2H5f{fR  
} gnmKh>0@6o  
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u
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public void setNSplitter(int nCount) o.t$hv|  
{ O"4Q=~Y  
nSplitter = nCount; ^yUel.N5"  
} l%*KBME  
} PL/as3O^A  
2wE?O^J  
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/* 5EDN 9?a  
**Utility.java &^e%gU8!\  
*/ I*R[8|  
package NetFox; _aVrQ@9  
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public class Utility { Z%~j
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public Utility() /
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{ LZm6\x  
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} Ed9ynJ~)X  
D.o|pTZ  
//线程睡眠 6>v`6  
public static void sleep(int nSecond) 7''l\3mIn  
{ kH1hsDe|&y  
try{ 1g6AzUXg  
Thread.sleep(nSecond); 78>)<$+d  
} vJDK]p<}  
catch(Exception e) obRR))  
{ *]~ug%a  
e.printStackTrace (); Y3r m')c  
} IlsXj`!e  
} O{a<f7 W  
pfgFHNH:  
//日志 n'=-bj`  
public static void log(String sMsg)
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{ Qj~m;F!  
System.err.println(sMsg); mdvooJ  
} LziEF-_  
;T~]|#T\6  

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public static void log(int sMsg) $.kP7!`:,  
{ yC !`6$  
System.err.println(sMsg); wXp A1,i  
} IW3ZHmrpA  
} t9SzZ2E  
{]<l|qK  
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/* SV16]V
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**TestMethod.java =8$//$  
*/ | 2BIAm]  
package NetFox; {8UYu2t  
*"` dO9Yf_  
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public class TestMethod { OiX
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public TestMethod() $9<q'hf<w  
{ ///xx/weblogic60b2_win.exe @#K19\dQ  
try{ yjUZ40Dq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ov"]&e(I[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =3OK3|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); km2('t7?  
fileFetch.start(); ;LE4UOK  
} py.lGywb_  
catch(Exception e){e.printStackTrace ();} /%9D$\  
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} }#'wy  
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public static void main(String[] args) %JM:4G|q  
{ $ysemDq-a\  
new TestMethod(); `Bk7W]{L  
} R>SS\YC'X  
} t!RR5!  
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