http断点续传简单实现（java)

/* &fhurzzAm  
**SiteFileFetch.java mqc Z3lsv  
*/ 3Ty{8oUs^  
package NetFox; -#M~NbI,  
import java.io.*; l'8TA~  
import java.net.*; =QO[zke:  
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b'"%  
public class SiteFileFetch extends Thread { ;pK"N:|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `%I{l  
long[] nStartPos; //开始位置 ##ea-"m8  
long[] nEndPos; //结束位置 #/=
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 3t6'5{  
long nFileLength; //文件长度 yk6UuI^/  
boolean bFirst = true; //是否第一次取文件 #{cpG2Rs  
boolean bStop = false; //停止标志 yj9gN}+  
File tmpFile; //文件下载的临时信息 PY<V  
DataOutputStream output; //输出到文件的输出流 WG r\R  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5Cka."bQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException &b8D'XQu  
{ +ANIm^@  
siteInfoBean = bean; S.>9tV2Ca  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +-137!x\q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #$)rwm.jW?  
if(tmpFile.exists ()) H pfI  
{ =W^L8!BE'  
bFirst = false; Z6ex<[`I  
read_nPos(); ?kefRev<#h  
} R6.#gb8^oS  
else +34jot.!  
{ )BrqE uX@"  
nStartPos = new long[bean.getNSplitter()]; Gnq~1p5^  
nEndPos = new long[bean.getNSplitter()]; 2b` M(QL  
}  `.-C6!  
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} G\AQql(f4  
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public void run() dPX>A4wp  
{ IsL/p3|  
//获得文件长度 :|Ty 0>k  
//分割文件 E#]%e^  
//实例FileSplitterFetch X;RI7{fW%X  
//启动FileSplitterFetch线程 m<ruFxY  
//等待子线程返回 :HQ/vVw'"9  
try{ |{"7/~*[  
if(bFirst) !A0bbJ  
{ rnaDo\5  
nFileLength = getFileSize(); 9?6$2I  
if(nFileLength == -1) .r"?w  
{ 9>P(eN  
System.err.println("File Length is not known!"); [!
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} IGQ8-#=  
else if(nFileLength == -2) 0~+k  
{ ((q(Q9(F  
System.err.println("File is not access!"); je%12DM  
} =?aB@&  
else __npX_4%S  
{ #O ]IXo(5z  
for(int i=0;i<nStartPos.length;i++) aoX$,~oI5  
{ 4!|ar?Zy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r&RSQHa)  
} ^Y |s^N  
for(int i=0;i<nEndPos.length-1;i++) =c4U%d2  
{ J6P Tkm}^  
nEndPos = nStartPos[i+1]; q;JQs:U!  
} ;
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nEndPos[nEndPos.length-1] = nFileLength; HPB1d!^  
} )YnN9"8  
} mYX) =
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x N)Ck76  
//启动子线程 j=4>In?x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,Fiiw  
for(int i=0;i<nStartPos.length;i++) M?lr#}d  
{ B\yid@e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yd'ke,Je  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TXv#/@  
nStartPos,nEndPos,i); !y.7"G*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3\ed4D  
fileSplitterFetch.start(); &|eQLY #l  
} 2ra4t]f6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hI0l2OE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `Fr$q1qae{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", i=@*F$,  
nEndPos = " + nFileLength); L4%LE/t|e  
// fileSplitterFetch[nPos.length-1].start(); jRc#>;dN  
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//等待子线程结束 !hUyX}{`j  
//int count = 0; <KX#;v!I  
//是否结束while循环 oef(i}8O@  
boolean breakWhile = false; M:E#}(
 
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while(!bStop) AaVlNjB  
{ M-hnBt  
write_nPos(); r9[J3t*({~  
Utility.sleep(500); g;T`~  
breakWhile = true; 00+5a TrE  
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for(int i=0;i<nStartPos.length;i++) (B5G?cB9  
{ L\I/2aiE  
if(!fileSplitterFetch.bDownOver) ~MF. M8  
{ _nUuiB>  
breakWhile = false; ,*US) &x  
break; "^`AS"z'  
} m{|n.b  
} !v=ha%w{  
if(breakWhile) NT'Yh  
break; =1C9lKm  
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wvD|c%   
//count++; J5wq}<8  
//if(count>4) Zh*I0m
   
// siteStop(); w'C(? ?mH  
} FU zY&@Y  
= 4L.  
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System.err.println("文件下载结束！"); wuCODz@~  
} 4[D@[kAs  
catch(Exception e){e.printStackTrace ();} KVBz=  
} XQ>m8K?\d  
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//获得文件长度 -VL3em|0  
public long getFileSize() Jh1fM`kB5K  
{ }tN"C 3)@  
int nFileLength = -1; y$rp1||lH  
try{ ZC"p^~U_e[  
URL url = new URL(siteInfoBean.getSSiteURL()); c)?y3LX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7o3f5"z  
httpConnection.setRequestProperty("User-Agent","NetFox"); *"ws
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int responseCode=httpConnection.getResponseCode(); 6Y=)12T  
if(responseCode>=400) i{.!1i:  
{ [||$1
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processErrorCode(responseCode); raCxHY  
return -2; //-2 represent access is error B^Vb=* QRo  
} y7JJ[:~~  
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String sHeader; e([}dz  
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for(int i=1;;i++) ebf0;1!  
{ qbjRw!2?w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C 7v 8  
//Utility.log(in.readLine()); :7'anj  
sHeader=httpConnection.getHeaderFieldKey(i); \O[Cae:^?  
if(sHeader!=null) n,`&f~tap  
{ ` 6PdMvF  
if(sHeader.equals("Content-Length")) w;XXjT  
{ ffdyDUzQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z' @F@k6  
break; ~e|~c<!z8@  
} |#k1a:  
} <Fi/!  
else ZDlMk
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break; m6s32??m  
} uv,t(a.^  
} _|3n h;-m  
catch(IOException e){e.printStackTrace ();} /p~gm\5Z  
catch(Exception e){e.printStackTrace ();} w1[F]|  
a!;?!f-i  
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Utility.log(nFileLength); I%
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return nFileLength; X=lOwPvP  
} |VIBSty2d  
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//保存下载信息（文件指针位置） ds`a6>746  
private void write_nPos() )]'?yS"  
{ E1=]m  
try{ Lf3:' n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
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output.writeInt(nStartPos.length); o@}Jd0D4  
for(int i=0;i<nStartPos.length;i++) QHOem=B  
{ C;_10Rb2ut  
// output.writeLong(nPos); -rUn4a  
output.writeLong(fileSplitterFetch.nStartPos); 7tJPjp4l  
output.writeLong(fileSplitterFetch.nEndPos); ^J?I-LG  
} bUt?VR}P(  
output.close(); DJhi>!xJ  
} $Ad 5hkz  
catch(IOException e){e.printStackTrace ();} ~)ls.NXI  
catch(Exception e){e.printStackTrace ();} Pn0V{SJOJ%  
} B+ +:7!  
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//读取保存的下载信息（文件指针位置） D3$}S{Yw1  
private void read_nPos() El,p}Bi.  
{ M(xd:Fa?  
try{ ;a2TONW   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XDU&Z2A  
int nCount = input.readInt(); {2A/@$?  
nStartPos = new long[nCount]; z>~Hc8*]3  
nEndPos = new long[nCount]; ?Yxk1Y4ig)  
for(int i=0;i<nStartPos.length;i++) jT%k{"+>+?  
{ i!9yN:m0  
nStartPos = input.readLong(); K[O'@v  
nEndPos = input.readLong(); s#>Bwn&b)  
} )=#QTiJ  
input.close(); ?J|~G{yH  
} .>_p7=a  
catch(IOException e){e.printStackTrace ();} GHfsq|*j,Z  
catch(Exception e){e.printStackTrace ();} Q u{#4qToA  
} 1t6VS3  
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private void processErrorCode(int nErrorCode) Mz_*`lRN  
{ |}t[-a  
System.err.println("Error Code : " + nErrorCode); ;vnG  
} \^i/:  
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//停止文件下载 HsO4C)/  
public void siteStop() B/7
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{ P >HEV a  
bStop = true; va[@XGaC3  
for(int i=0;i<nStartPos.length;i++) )Z2HzjE  
fileSplitterFetch.splitterStop(); X H,1\J-S  
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} G$( B26  
}
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//负责部分文件的抓取 _Gvn1"l  
**FileSplitterFetch.java |5^tp  
*/ e4ym6q<6!  
package NetFox; kO>F, M  
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import java.io.*; v!JQ;OX  
import java.net.*; BxVo
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public class FileSplitterFetch extends Thread { p'tB4V qT  
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String sURL; //File URL }&M$  
long nStartPos; //File Snippet Start Position +zn&DG0\X  
long nEndPos; //File Snippet End Position Ev+m+  
int nThreadID; //Thread's ID Z:j6AF3;  
boolean bDownOver = false; //Downing is over b=(?\  
boolean bStop = false; //Stop identical QpbyC_:;$4  
FileAccessI fileAccessI = null; //File Access interface p;$Vw6W=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uY{V^c#mv  
{ ziPE(B  
this.sURL = sURL; J0K25w  
this.nStartPos = nStart; v0v%+F#>@  
this.nEndPos = nEnd; H=,0p  
nThreadID = id; sTv;Ogs.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %iMRJ}8(7  
} jzt$  
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public void run() WCJ$S\#  
{ QU{|S.\  
while(nStartPos < nEndPos && !bStop) b5NPG N  
{ >LS*G qjq  
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try{ ;c};N(2  
URL url = new URL(sURL); zI1-l9 o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qv4g#jX{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9OI&De5?=V  
String sProperty = "bytes="+nStartPos+"-"; 
#ub!
 
httpConnection.setRequestProperty("RANGE",sProperty); OZ2YflT  
Utility.log(sProperty); AXBf\)[  
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InputStream input = httpConnection.getInputStream(); ! 3&_#VO  
//logResponseHead(httpConnection); afE`GG-  
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byte[] b = new byte[1024]; %z9eVkPI~  
int nRead; ?7n(6kmj4Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uj 6dP  
{ G3r9@2OC  
nStartPos += fileAccessI.write(b,0,nRead); -`knSR  
//if(nThreadID == 1) `GGACH3#s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x|3f$ =b  
} e&*< "WN  
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Utility.log("Thread " + nThreadID + " is over!"); s{q)P1x  
bDownOver = true; X%1j-;Wr@  
//nPos = fileAccessI.write (b,0,nRead); Y5rR  
} H#zsk*=QD  
catch(Exception e){e.printStackTrace ();} Dl/Jlsd@  
} 7=Vs1TVc  
} ;}/@ar7s3  
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//打印回应的头信息  +=Xgi$  
public void logResponseHead(HttpURLConnection con) 02|f@bP.  
{ Gn+3OI"  
for(int i=1;;i++) $mS]K!\  
{ 39j "z8n  
String header=con.getHeaderFieldKey(i); |gl~wG1@  
if(header!=null) KaRdO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )+!~xL  
Utility.log(header+" : "+con.getHeaderField(header)); /<J&ZoeJB  
else ze5Hg'f  
break; ?uiQ'}
 
} e<Pbsj  
} 1a|Z!Vzi  
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public void splitterStop() '1o1=iJN@$  
{ ,sU#{.(  
bStop = true; ">?ocJ\9  
} ?z "fp$  
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} o'9K8q\1  
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/* X[F<sxw  
**FileAccess.java Uwd^%x*  
*//文件访问(定位，写) ~}B6E)   
package NetFox; aahAUhF  
import java.io.*; H\BhAf  
gc%aaYf>  
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public class FileAccessI implements Serializable{ zP[_ccW@  
_3G;-iNX;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m%mA0r  
RandomAccessFile oSavedFile; -85]x)JE  
long nPos; ~hJ/&,vH!  
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public FileAccessI() throws IOException W>ZL[B
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{ C&d%S|:IR  
this("",0); \dIc_6/D1  
} !>%U8A  
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public FileAccessI(String sName,long nPos) throws IOException ZjlFr(  
{ cy0 %tsB|  
oSavedFile = new RandomAccessFile(sName,"rw"); Y6_%HYI$  
this.nPos = nPos; < C{-ph  
oSavedFile.seek(nPos); MT`gCvoF4P  
} a,B2;4"  
)+
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public synchronized int write(byte[] b,int nStart,int nLen) 2<Vw :+,  
{ ;B8#Nf  
int n = -1; >lD*:#o  
try{ )kMA_\$,  
oSavedFile.write(b,nStart,nLen); "K.XoG4|  
n = nLen; Nk~Xz  
} $Vu%4kq  
catch(IOException e) ]e*Zx;6oi  
{ 81O\BO.T  
e.printStackTrace (); u!&w"t61Nd  
} t#kPEiD  
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return n; Xp(e/QB  
} ;(]O*{F7k  
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} =44hI86  
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/*
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**SiteInfoBean.java @uIY+_E40g  
*/ @B<B#  
package NetFox; --ED]S 8  
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public class SiteInfoBean { /}_OCuJJ,  
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private String sSiteURL; //Site's URL R@h@@lSf  
private String sFilePath; //Saved File's Path IW48Sg  
private String sFileName; //Saved File's Name "E? 8.`T  
private int nSplitter; //Count of Splited Downloading File )gO=5_^u*o  
=cy;{2S'p  
.JR"|;M}  
public SiteInfoBean() a@1r3az  
{//nSplitter的缺省值为5 HA +EuQE"  
//default value of nSplitter is 5 oD5VE  
this("","","",5); s_(%1/{  
} :z;}:+7n  
k\:f2%!!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |2yTt*!-r  
{ &9Vm3X  
sSiteURL= sURL; 9.bMA<X  
sFilePath = sPath;
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sFileName = sName; v-*CE[  
this.nSplitter = nSpiltter; +y+-~;5iv  
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} M6ol/.G[  
*`}4]OGv.  
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public String getSSiteURL() -
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{ VrV* -J'  
return sSiteURL; ^':Az6Z  
} \M]w I  
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public void setSSiteURL(String value) &FQ]`g3_@  
{ NNWbbU3wjh  
sSiteURL = value; $N7:;X"l  
} qXHr"  
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<  
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public String getSFilePath() $Cr? }'a  
{ )~hsd+ 0t
 
return sFilePath; !Ua74C
 
} R~-r8dWcw  
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public void setSFilePath(String value) Ga4Ru  
{ ~YxLDo'.t  
sFilePath = value; ]rEFWA  
} gE,i
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public String getSFileName() 48.2_H<  
{ 8T5s6EmIOW  
return sFileName; {FR#je  
} O5PCR6U  
sje}E+{[  
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public void setSFileName(String value) 'ADaz75`*r  
{ E'p5  
sFileName = value; %@<
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} U=<E,tM  
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public int getNSplitter() \ H#zRSbZ  
{ jW6~^>S  
return nSplitter; q#v&&]N=  
} ~o:lh],~  
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public void setNSplitter(int nCount) a;p3M
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{ XVi?-/2  
nSplitter = nCount; W M/pP?||
 
} `0+zF-  
} A7.$soI\  
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/* C& 0iWY\a  
**Utility.java <C\snB  
*/ #uNQ+US0  
package NetFox; "Vp+e%cqG  
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public class Utility { clQN@1] M  
7O{c>@\  
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public Utility() Xj.Tg1^K"  
{ hV_eb6aj}P  
#$(F&>pj  
^{8r(1,  
} ?6B n&qa  
Oy$*ZG)  
//线程睡眠 %n`wU-?lK  
public static void sleep(int nSecond) k<uC[)_  
{ sfez0Uqe.~  
try{ vukI`(#  
Thread.sleep(nSecond); @bdGV#*d  
} /jih;J|  
catch(Exception e) #SQao;>  
{ U7U-H\t7  
e.printStackTrace (); lmb5Z-xB  
} qp>O#tj[  
} |yiM7U,i  
t&(}`W  
//日志 ;5 cg<~t  
public static void log(String sMsg) t^.U<M  
{ <5MnF  
System.err.println(sMsg); +)Tt\Q%7  
} Hep]jxp+  
n{j14b'  
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public static void log(int sMsg) <#w0=W?  
{ O3#4B!J$E  
System.err.println(sMsg); [ajF  
} I&|%Fn  
} K2<Q9 ,vt  
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:0ZFbIy  
/* uArs[e|f  
**TestMethod.java zYfn;s%A  
*/ [gFpFz|b<  
package NetFox; P6*IR|  
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public class TestMethod { fkWuSGi  
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public TestMethod() R[5*]$(b  
{ ///xx/weblogic60b2_win.exe A:F*Y%ZW  
try{ \?&P|7N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +N2?fgA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t_c;4iE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Qjh5m5e  
fileFetch.start(); >5)E\4r-  
} A!&p,KfT5+  
catch(Exception e){e.printStackTrace ();} 2MmqGB}YcW  
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} !
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public static void main(String[] args) E[HXbj"  
{ TTpK8cC  
new TestMethod(); #R<4K0Xan  
} Epsc2TuH7  
} J3cbDE%^m  
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