http断点续传简单实现（java)

/* x1m8~F  
**SiteFileFetch.java P[rAJJN/E  
*/ ub`z7gL  
package NetFox; M
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import java.io.*; m\*&2Na  
import java.net.*; YW8K $W  
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public class SiteFileFetch extends Thread { pG,<_N@P  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lQh E]m>+  
long[] nStartPos; //开始位置 7XUhJN3n  
long[] nEndPos; //结束位置 8lU;y)Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gq H`GI  
long nFileLength; //文件长度 P<>[e9|  
boolean bFirst = true; //是否第一次取文件 ?@Z7O.u  
boolean bStop = false; //停止标志 /J1S@-  
File tmpFile; //文件下载的临时信息 u{g]gA8s  
DataOutputStream output; //输出到文件的输出流 ]~?S~l%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2-8YSHlh  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'is,^q:@  
{ ..??O^  
siteInfoBean = bean; |9+bSH9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IS
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -`-ACWeNV  
if(tmpFile.exists ()) >:.w7LQy/  
{ c*.G]nRc  
bFirst = false; sEoZ1E  
read_nPos(); 8BHL  
} OfD@\;L  
else VKT@2HjNT`  
{ G{F6  
nStartPos = new long[bean.getNSplitter()]; 5XzrS-I+X@  
nEndPos = new long[bean.getNSplitter()]; `if
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} btUq  
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} ~;}\zKQKE  
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public void run() `f%&<,i  
{ ~@xT]D!BQ  
//获得文件长度 ~q{\;  
//分割文件 Dz,uS nnm  
//实例FileSplitterFetch DD2adu^  
//启动FileSplitterFetch线程 <H<!ht%q3  
//等待子线程返回 ,r@xPZPz:e  
try{ Dp^"J85}   
if(bFirst) '-`O. 4u  
{ 1JIG+ZNmd  
nFileLength = getFileSize(); R_maNfS]Z  
if(nFileLength == -1) aZP2
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{ 8098y,mQe  
System.err.println("File Length is not known!"); 4/b(Y4$,[r  
} Xc{ZN1 4n  
else if(nFileLength == -2) >Q&CgGpW$  
{ B@d1xjp)']  
System.err.println("File is not access!"); n4Vwao/9x  
} wqcDAO(  
else {JXf*IJ  
{ B<Ol+)@,}  
for(int i=0;i<nStartPos.length;i++) 3]N q@t  
{ ?fB5t;~E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gglf\)E;}E  
}
;;M"hI3@  
for(int i=0;i<nEndPos.length-1;i++) s}s|~  
{
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nEndPos = nStartPos[i+1]; lHcA j{6  
} VXA[TIqp  
nEndPos[nEndPos.length-1] = nFileLength; xg?auje  
} ^1R"7h  
} DjY8nePyE  
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|4Qx=x>  
//启动子线程 lVP |W:~K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #vtN+E  
for(int i=0;i<nStartPos.length;i++) "3wv:BL  
{ ^}hJL7O'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JwB"\&'1ZS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bf1)M>g,O  
nStartPos,nEndPos,i); l~NEGb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7_KXD#  
fileSplitterFetch.start(); P8<hvMF  
} {tc57jsr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); fCg@FHS&^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h D.)M  
nEndPos = " + nFileLength); $T?]+2,6;  
// fileSplitterFetch[nPos.length-1].start(); S@Iw;V  
Y([d;_#P  
>nK%^T  
//等待子线程结束 |kseKZ3  
//int count = 0; ; h85=l<8u  
//是否结束while循环 `w+1C&>^[  
boolean breakWhile = false; FfG%C>E6~  
' Rc#^U*n  
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while(!bStop) r%|A$=[Q  
{ r8,om^N6  
write_nPos(); \2>3Opt  
Utility.sleep(500); W~yLl%  
breakWhile = true; H{%H^t>  
+?Ez} BP  
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for(int i=0;i<nStartPos.length;i++) `;cz;"  
{ d8o ewkiR  
if(!fileSplitterFetch.bDownOver) :BD>yOlG  
{ #Kl}= 1 4  
breakWhile = false; #q;z8 @  
break; VE$t%QT  
} (:n|v%  
} /NU103F yt  
if(breakWhile) ]-bQNYKX  
break; P#;Th8k{K2  
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NO4Z"3Pd_  
//count++; i?-Y  
//if(count>4) h/?6=D{  
// siteStop(); dp<$Zw8BE  
} V{ |[oIp  
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System.err.println("文件下载结束！"); [0!{_E)<  
} N}mh}  
catch(Exception e){e.printStackTrace ();} aq$q ~,E  
} <u0,Fp  
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6 64q~_@B1  
//获得文件长度 #xp(B5  
public long getFileSize() ) EXJ   
{ cmDT +$s  
int nFileLength = -1; mNDuwDd$S  
try{ VB"(9O]  
URL url = new URL(siteInfoBean.getSSiteURL()); MI*Sq\-i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ag;dc  
httpConnection.setRequestProperty("User-Agent","NetFox"); [.&[<!,.  
=:~(m  
QBihpA1;  
int responseCode=httpConnection.getResponseCode(); vRr9%zx  
if(responseCode>=400) vD26;S.y[a  
{ U=m=1FYaG  
processErrorCode(responseCode); Nfb`YU=  
return -2; //-2 represent access is error {7X~!e|w  
} R=$Ls6z  
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String sHeader; ~Z/7pP+  
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ab
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for(int i=1;;i++) WeVi]n  
{ jQ$BPEG&X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nk/vGa4
  
//Utility.log(in.readLine()); CDCC1BG"  
sHeader=httpConnection.getHeaderFieldKey(i); fM^<+o@  
if(sHeader!=null) ri+U0[e3  
{ sfI N)jh  
if(sHeader.equals("Content-Length")) %?=)!;[  
{ m UgRm]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~gddcTp  
break; KlO(o#&N  
} v8'5pLt"  
} %wL,v.}  
else :-Wv>V\t  
break; uvv.WbZ  
} d+5:Qrr  
} tlGWl0V?7Q  
catch(IOException e){e.printStackTrace ();} 'C~9]Y].  
catch(Exception e){e.printStackTrace ();} rBfg*r`)  
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Utility.log(nFileLength); VGZ6  
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return nFileLength; 4bI*jEc\[  
} 9L"?wv  
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//保存下载信息（文件指针位置） fl)zQcA  
private void write_nPos() Eem g  
{ (}~ucI<~  
try{ e/94y6*
>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oMc1:=EG  
output.writeInt(nStartPos.length); x'i0KF   
for(int i=0;i<nStartPos.length;i++) v[L[A3`"/  
{ &+- e  
// output.writeLong(nPos); ) ,Npv3(  
output.writeLong(fileSplitterFetch.nStartPos); (\& 62B1  
output.writeLong(fileSplitterFetch.nEndPos); m6MaX}&zv  
} j38 6gL  
output.close();
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} all*P #[X  
catch(IOException e){e.printStackTrace ();} ? s4oDi|:  
catch(Exception e){e.printStackTrace ();} Q|//Z  
} 8\_*1h40s  
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//读取保存的下载信息（文件指针位置） 'tuBuYD\  
private void read_nPos() b1)\Zi  
{ %zflx~  
try{ K~@`o-Z[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); **HrWM%?8o  
int nCount = input.readInt(); Yb9cW\lr  
nStartPos = new long[nCount]; (&c,twa~  
nEndPos = new long[nCount]; NWnWk  
for(int i=0;i<nStartPos.length;i++) XtzOFx/  
{ ]}~4J.Yn  
nStartPos = input.readLong(); R@$+t:}  
nEndPos = input.readLong(); d?}hCo=/Xq  
} }.t^D|  
input.close(); ;qb Dbg  
} PW)8aLU  
catch(IOException e){e.printStackTrace ();} O! (85rp/  
catch(Exception e){e.printStackTrace ();} Ql8^]gbp+  
} ^'YHJEK  
}VZM,.w  
#[(gIOrNn8  
private void processErrorCode(int nErrorCode) @ExLh9  
{ _.-#E$6s#q  
System.err.println("Error Code : " + nErrorCode); WG\Q5k4Ba  
} Gym#b{#":  
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//停止文件下载 B G5X_s0/  
public void siteStop() q;No"_aAd  
{ L6xB`E9  
bStop = true; Iht'e8)gq  
for(int i=0;i<nStartPos.length;i++) B'#4;R!8P=  
fileSplitterFetch.splitterStop(); jm+blB^%K  
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} ,3k@L\$.x  
} ;Rs.rl>;t/  
//负责部分文件的抓取 }pKv.  
**FileSplitterFetch.java }1,'rmT
 
*/ LS{bg.
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package NetFox; [\a:4vDAbi  
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import java.io.*; n_1jHJo  
import java.net.*; dB
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public class FileSplitterFetch extends Thread { W
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String sURL; //File URL :q(D(mK  
long nStartPos; //File Snippet Start Position }'v{dK  
long nEndPos; //File Snippet End Position WqR7uiCi  
int nThreadID; //Thread's ID 1*L^^%w  
boolean bDownOver = false; //Downing is over "~_$T@^k>  
boolean bStop = false; //Stop identical ?P%|P  
FileAccessI fileAccessI = null; //File Access interface )=y.^@UT@  
4`$5 _} j!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IeH^Wm&^  
{ KM5jl9Vv  
this.sURL = sURL; g%ZdIKj!  
this.nStartPos = nStart; }M^_Z#|,  
this.nEndPos = nEnd; >B`Cch/'U  
nThreadID = id; Ywmyr[Uh'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lK "'nLL  
} )ni"qv~J  
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public void run() dr.**fGYde  
{ bAN10U  
while(nStartPos < nEndPos && !bStop) h|K\z{ A  
{ SwyaYK  
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try{ u$apH{  
URL url = new URL(sURL); sf fV.cC`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >ze>Xr'm5=  
httpConnection.setRequestProperty("User-Agent","NetFox"); j[_t6Z  
String sProperty = "bytes="+nStartPos+"-"; ~(
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httpConnection.setRequestProperty("RANGE",sProperty); >9 q]>fJ  
Utility.log(sProperty); }*0,>w>  
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InputStream input = httpConnection.getInputStream(); ,m2A p\l  
//logResponseHead(httpConnection); tX@0:RX%  
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byte[] b = new byte[1024]; ?$UH9T9)  
int nRead; I).=v{@9V<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  -PcS(  
{ &\JK%X.Jlt  
nStartPos += fileAccessI.write(b,0,nRead); s4x'f$r  
//if(nThreadID == 1) W,xi>5k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mk#>Dpy?  
} sGXp}{E9  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; {CW1t5$*  
//nPos = fileAccessI.write (b,0,nRead); >L#];|  
} J@oEV=L  
catch(Exception e){e.printStackTrace ();} 29&sydu  
} /p[|DJoM  
} 83mlZ1jQz  
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Q&oC]u(="&  
//打印回应的头信息 q>Q:X3  
public void logResponseHead(HttpURLConnection con) MDMtOfe|  
{ mgmWDtxN  
for(int i=1;;i++) 6H(fk1E  
{ \pjRv  
String header=con.getHeaderFieldKey(i); 5F'%i;)oq  
if(header!=null) vpZu.#5c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8 m%>:}o  
Utility.log(header+" : "+con.getHeaderField(header)); SQ1M4:hP  
else Mfnlue](  
break; 0!9?H1>  
} ;X?Ah  
} \(.nPW]9  
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public void splitterStop() sN}s61  
{ bBkm] 
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bStop = true; g*:ae;GP  
} C><<0VhU  
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} D6&mf2'u  
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/* >P6^k!R1y  
**FileAccess.java v#Cz&j  
*//文件访问(定位，写) )GiFkG  
package NetFox; XM$5S+e  
import java.io.*; F&W0DaH  
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public class FileAccessI implements Serializable{ D..{|29,:  
'Z*\1Ci  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [ 4?cM\_u@  
RandomAccessFile oSavedFile; kPx]u\  
long nPos; @Og\SZhn  
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public FileAccessI() throws IOException E5,%J  
{ f7EIDFX>pt  
this("",0); >,w
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} lKh2LY=j  
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public FileAccessI(String sName,long nPos) throws IOException I3}HNGvU  
{ >cwJl@wx-  
oSavedFile = new RandomAccessFile(sName,"rw"); ~6@c]:  
this.nPos = nPos; p\\P50(-  
oSavedFile.seek(nPos); Z/V`Z* fy  
} %fn'iKCB  
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public synchronized int write(byte[] b,int nStart,int nLen) 
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{ j:rs+1bc  
int n = -1; Y0P}KPD  
try{ n&2=6$*,k  
oSavedFile.write(b,nStart,nLen); FT*yso:X/  
n = nLen; OEy:#9<'  
} u):%5F/  
catch(IOException e)  m+72C]9  
{ ),D`ZRXS  
e.printStackTrace (); s]nGpA[!  
} c"f-$^<  
:|3"H&FWK  
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return n; FT3,k&i  
} +,vJ7  
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} WQIM2_=M  
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/* Zi<Sw  
**SiteInfoBean.java {jx#^n&5R  
*/ yO$r'9?,*  
package NetFox; :N*q;j>  
Ru9pb~K  
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public class SiteInfoBean { _Ssv:xc,  
(_%JF[W  
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private String sSiteURL; //Site's URL 4Rrw8Bw  
private String sFilePath; //Saved File's Path %CsTB0Y7n,  
private String sFileName; //Saved File's Name ZaNyNxbp>z  
private int nSplitter; //Count of Splited Downloading File 6gg#Z  
%Zl_{Q]h  
%`s9yRk9>E  
public SiteInfoBean() iaa (ce  
{//nSplitter的缺省值为5 0+2Matk>.  
//default value of nSplitter is 5 1^WA  
this("","","",5); 8&2gM  
} 2\z`G  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ('o; M:  
{ E3.W#=o  
sSiteURL= sURL; VtPoc(o4]  
sFilePath = sPath; !+
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sFileName = sName; i/O,`2  
this.nSplitter = nSpiltter; G"UH4n[1ur  
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,rl <ye*&  
} w_z^5\u0  
c;t(j'k`  
\ \mO+N47i  
public String getSSiteURL() z7l;|T  
{ C"m0"O>  
return sSiteURL; g9lg  
} &_%+r5  
IDk:jO  
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public void setSSiteURL(String value) hk$nlc|$  
{ ~NW5+M(u  
sSiteURL = value; oj4)7{  
} Kp=3\)&  
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public String getSFilePath() ks`  
{ %Pvb>U(Xs  
return sFilePath;  /qQ2@k  
} T[!q&kFB  
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public void setSFilePath(String value) WO*WAP)n  
{ d<cbp[3F  
sFilePath = value; +MoxvW6  
} xY}j8~k  
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public String getSFileName() H><mcah  
{ #&8pp8wd,}  
return sFileName; Q@.9wEAJ  
} fD}]Mi:V  
d=OO(sf  
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public void setSFileName(String value) (Gk]<`d#N  
{ iU+,Jeu  
sFileName = value; mS;Q8Crh  
} 1#_j6Q2  
6o23#JgN  
Ecl7=-y  
public int getNSplitter() }~,cCtg:o  
{ #w?%&,Kp  
return nSplitter; pO+wJ|f  
} <EN[s  
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public void setNSplitter(int nCount) *8eh%3_$h  
{ ]x{H  
nSplitter = nCount; QMpA~x_m  
} 90696v.

 
} x=|@AFI  
['`'&+x&!  
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/* L#MxB|fcr  
**Utility.java (=B7_jrl  
*/ Y$5v3E\uc  
package NetFox; b
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#Z5Wk  
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public class Utility { XzFqQ-H  
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public Utility() I,Y^_(JW  
{ ,(?4T
~  
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} (?wKBUi  
K4L#%KUPW  
//线程睡眠 5]ob;tAm  
public static void sleep(int nSecond) 6j![m+vo%  
{ ZlXs7 &_  
try{ *3oQS"8  
Thread.sleep(nSecond); / UBAQ8TR  
} KAEpFobYo  
catch(Exception e) v^E2!X  
{ mw.aavB  
e.printStackTrace (); z1A-EeT  
} .b)(_*  
} $l"(tB7d  
AMfu|%ZL  
//日志 ?%n9g)>Yej  
public static void log(String sMsg) 0kEq|k9  
{ 2Rt ZTn  
System.err.println(sMsg); h"m7r4f  
} 'm((G4  
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'*.};t~;"d  
public static void log(int sMsg) :fUmMta  
{ q@> m~R  
System.err.println(sMsg); 7:<>#  
} 5lY9  
}  .l'QCW9  
x&p=vUuukP  
(#BA{9T,^  
/* 3F3?be  
**TestMethod.java  3".W  
*/ $nN$"  
package NetFox; ?!vW&KJZx  
69L&H!<i:  
3<lDsb(}0A  
public class TestMethod { evP`&23t
P  
)E|Bb=%  
m 9Q{)?J7  
public TestMethod() 2/WXdo  
{ ///xx/weblogic60b2_win.exe nV1
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try{ 5lbh "m=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C
Q ?|=cN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J0o[WD$Ax  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'ZZ/:MvQa  
fileFetch.start(); u[@*}|uXM  
} YN3uhd[2  
catch(Exception e){e.printStackTrace ();} q3t@)+l>*  
x;/3_"$9>\  
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} 4|UIyDt8  
4
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6w#v,RDEu  
public static void main(String[] args) _\zfXHp  
{ TY}?>t+  
new TestMethod(); u^$ CR  
} G})mw  
} *{bqHMd4L  
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