http断点续传简单实现（java)

/* Vi|jkyC8  
**SiteFileFetch.java rN~`4mZ  
*/ e4b~s  
package NetFox; Mww]l[1'EL  
import java.io.*; D{l((t3=T  
import java.net.*; .0|J+D  
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public class SiteFileFetch extends Thread { Vwqfn4sx?i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean YC_^jRB8n  
long[] nStartPos; //开始位置 Vel;t<1  
long[] nEndPos; //结束位置 u@EM,o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {EUH#':  
long nFileLength; //文件长度 IXN4?=)I  
boolean bFirst = true; //是否第一次取文件 M5V1j(URE  
boolean bStop = false; //停止标志 |<*(`\'w  
File tmpFile; //文件下载的临时信息 !%X`c94  
DataOutputStream output; //输出到文件的输出流 D+3Y.r9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "p{'984r<  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;Z_C3/b  
{ eQx"nl3U%  
siteInfoBean = bean; #c>MUC(?s:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $(R) =4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !q/lgpEi  
if(tmpFile.exists ()) [mPdT^h  
{ `[\phv  
bFirst = false; ^-!HbbVv  
read_nPos(); "/fs%F  
} h;KK6*Z*$E  
else S\ZAcz4  
{ z{d5Lrk  
nStartPos = new long[bean.getNSplitter()]; "/?qT;<$)  
nEndPos = new long[bean.getNSplitter()]; 0d ->$gb  
} sriz b  
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} '5U$`Xe1  
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public void run() ["<(\v9P)  
{ jTr4A-"  
//获得文件长度 ;NeP&)Td  
//分割文件 '>Y 2lqa  
//实例FileSplitterFetch =7Vl{>*1N  
//启动FileSplitterFetch线程 0gD0}nH  
//等待子线程返回 v`BG1&/|  
try{ cvA\C_  
if(bFirst) WN#lfn8 7  
{ \2xBOe-a]  
nFileLength = getFileSize(); J\'5CG  
if(nFileLength == -1) ~,68S^nP)H  
{ @t8kN6.  
System.err.println("File Length is not known!"); ~bTae =FP  
} S\5k'ifh  
else if(nFileLength == -2) b H_pNx81  
{ c$kb0VR  
System.err.println("File is not access!"); ON0+:`3\  
} Td1ba^J  
else v|(b,J3  
{ "D(8]EG=  
for(int i=0;i<nStartPos.length;i++) -3tBN*0+  
{ Rl4zTAI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); OX/.v?
c  
} PX2k,%  
for(int i=0;i<nEndPos.length-1;i++) oQnk+>}%  
{ XFTMT'9  
nEndPos = nStartPos[i+1]; vGwD~R  
} }@%ahRGx%9  
nEndPos[nEndPos.length-1] = nFileLength; BQ&q<6Tk  
} V )k, 9=  
} y32++b!  
MW~B[%/  
9[{>JRm.  
//启动子线程 aijGz<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2^#UO=ct  
for(int i=0;i<nStartPos.length;i++) ;sR6dT)  
{ ?_>^<1I1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G=HxD4l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NJf(,Mr*|  
nStartPos,nEndPos,i); ]}7rWs[|1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pEj^x[b`^  
fileSplitterFetch.start(); pptM&Y  
} MlK`sH6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zWs*kTtA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .*~u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /cC6qhkp%  
nEndPos = " + nFileLength); 9m!!b{  
// fileSplitterFetch[nPos.length-1].start(); QlYs7zZ  
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//等待子线程结束 ~po%GoH(K  
//int count = 0; Va Yu%  
//是否结束while循环 G7Abhb,  
boolean breakWhile = false; N@*wi"Q  
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while(!bStop) CQzjCRS d  
{ Wt9iL  
write_nPos(); (:-Jl"&R@  
Utility.sleep(500); #C1A5JE&  
breakWhile = true; ,r 2VP\hLh  
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for(int i=0;i<nStartPos.length;i++) BU:Ecchbr  
{ [AX"ne#M*  
if(!fileSplitterFetch.bDownOver) Sci4EGc  
{ /witDu7  
breakWhile = false; I\rZk9F  
break; ::OFW@dS  
} *V6QBe  
} Sm$j:xw<  
if(breakWhile) .pIR/2U\F  
break; e(w/m(!Wny  
{ w8 !K  
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//count++; *$Lz2 ]  
//if(count>4) Z-t}6c'Kg  
// siteStop(); :-u-hO5*8  
} G?-`>N-u  
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#  
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System.err.println("文件下载结束！"); e-iYJ?  
} ,V33v<|wc  
catch(Exception e){e.printStackTrace ();} J7ktfyQ0W  
} #5-A&  
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//获得文件长度 $35,\ZO>  
public long getFileSize()
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{ KIKq9*  
int nFileLength = -1; nEd M_JPv  
try{ umm\r&]A  
URL url = new URL(siteInfoBean.getSSiteURL()); *"ykTqa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L8:]`MQ0  
httpConnection.setRequestProperty("User-Agent","NetFox"); chO'Q+pw  
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int responseCode=httpConnection.getResponseCode(); ~Un64M?  
if(responseCode>=400) DhWWN>I  
{ D(qHf9  
processErrorCode(responseCode); P(pd0,%i;a  
return -2; //-2 represent access is error ]HyHz9QkL  
} G}P)vfcH  
L{2
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String sHeader; }O.LPQ0  
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for(int i=1;;i++) emv;m/&8  
{ (|<h^] y3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Bw3F7W~l  
//Utility.log(in.readLine()); p;qRm} 0}  
sHeader=httpConnection.getHeaderFieldKey(i); gHi~nEH  
if(sHeader!=null) m3xz=9Ve  
{ QT1:>k  
if(sHeader.equals("Content-Length")) l5=u3r9WYC  
{ GB<R7J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zP:~O  
break; e{fZ}`=7y  
} W>Mse[6`c  
} \;-=ODC  
else J4gI=@e  
break; n2n00%Wu[  
} #"Eks79s  
} S)"##-~`T  
catch(IOException e){e.printStackTrace ();} YKP=0 j3,  
catch(Exception e){e.printStackTrace ();} |?x^8e<*  
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Utility.log(nFileLength); e=gboR  
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return nFileLength; c8#T:HM|`  
} GFdZ`i  
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//保存下载信息（文件指针位置） 6Cl+KcJH  
private void write_nPos() v]WH8GI  
{ 9U2Px$E  
try{ ElQJ\%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
uQ:Qb|  
output.writeInt(nStartPos.length); 6oj4Rg+(  
for(int i=0;i<nStartPos.length;i++) OlEpid'Z  
{ 2;~KL-h0TK  
// output.writeLong(nPos); $42Au2Jg  
output.writeLong(fileSplitterFetch.nStartPos); '1CD- Bu  
output.writeLong(fileSplitterFetch.nEndPos); o-SRSu  
} oy2(Ag\  
output.close(); T$H2'tK|  
} WYSck&9  
catch(IOException e){e.printStackTrace ();} J#6LSD@(O  
catch(Exception e){e.printStackTrace ();} n&_YYEHx  
} @<vF]\Ce  
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//读取保存的下载信息（文件指针位置） HG3.~ 6X  
private void read_nPos() sL)Rg(rkx  
{ 5{')GTdX>  
try{ X!T|07#c  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TkA9tF
i  
int nCount = input.readInt(); \4OK!6LkI  
nStartPos = new long[nCount]; B^Xy0fq  
nEndPos = new long[nCount]; G3H#XK D  
for(int i=0;i<nStartPos.length;i++) HjV\lcK:v  
{ *I=_*LoG2  
nStartPos = input.readLong(); -"F0eV+y  
nEndPos = input.readLong(); 8dc538:q}  
} M|U';2hZN:  
input.close(); %v]7BV^%6  
} ER{yuw  
catch(IOException e){e.printStackTrace ();} BwJNi6,  
catch(Exception e){e.printStackTrace ();} IK8%Q(.c  
} L<0=giE  
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private void processErrorCode(int nErrorCode) +d=~LQ}*  
{ 7.%f01/i  
System.err.println("Error Code : " + nErrorCode); -<O JqB  
} )j\r,9<K+5  
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{U(Bfe^a,  
//停止文件下载 w]n4KR4  
public void siteStop() .SG0}8gW  
{ #xlZU  
bStop = true; /[0F6  
for(int i=0;i<nStartPos.length;i++) gC0;2  
fileSplitterFetch.splitterStop(); =Wj{]&`  
=h(7rU"Yz  
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} otU@X 3<_  
} _]P a>8X*  
//负责部分文件的抓取 _=uviMuE  
**FileSplitterFetch.java %=BtOM_2  
*/ . /Y&\<  
package NetFox; m+H%g"Zj  
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import java.io.*; hPcS, p{%  
import java.net.*; 1c'79YU  
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public class FileSplitterFetch extends Thread { T4eWbNSs  
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String sURL; //File URL j13riI3A  
long nStartPos; //File Snippet Start Position Ex6o=D2  
long nEndPos; //File Snippet End Position @2u#93Y  
int nThreadID; //Thread's ID D{>\-]\  
boolean bDownOver = false; //Downing is over N50fL  
boolean bStop = false; //Stop identical E$w#+.QP  
FileAccessI fileAccessI = null; //File Access interface 6Hda]y  
#aa1<-&H  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B9}E {)T?  
{ M=W 4:H,gx  
this.sURL = sURL; YtMlqF  
this.nStartPos = nStart; ]s_@n!  
this.nEndPos = nEnd; au}s=ua~i  
nThreadID = id; "tKNlHBu'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t|.Ft<c#  
} .W$ sxVXB  
7g5@vYS+  
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public void run() s*f1x N<  
{ qT$)Rb&  
while(nStartPos < nEndPos && !bStop) Y5n>r@)m  
{ c88_}%h?(  
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try{ B7|c`7x(  
URL url = new URL(sURL); -rO*7HO
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5:$Xtq  
httpConnection.setRequestProperty("User-Agent","NetFox"); ly[lrD0Kn.  
String sProperty = "bytes="+nStartPos+"-"; a/b92*&k  
httpConnection.setRequestProperty("RANGE",sProperty); k
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Utility.log(sProperty); >{b3>s~T  
};^}2Xo+  
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InputStream input = httpConnection.getInputStream(); 4b=
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//logResponseHead(httpConnection); \KCWYi]  
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byte[] b = new byte[1024]; AxEc^Co
f  
int nRead; >4~#%&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W1hX?!xp!  
{ <}cZi4l'  
nStartPos += fileAccessI.write(b,0,nRead); $
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//if(nThreadID == 1) G~(&3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aV#h5s  
} _\UIc;3Gl  
2 ^oGwx @  
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Utility.log("Thread " + nThreadID + " is over!"); L$kgK#T  
bDownOver = true; oK$'9c5<  
//nPos = fileAccessI.write (b,0,nRead); *y?[<2"$
 
} $C$ub&D ~"  
catch(Exception e){e.printStackTrace ();} H~eGgm;p  
} |*ReqM|_C  
} 3[.3dy7,Z  
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//打印回应的头信息 n_}aZB3;U  
public void logResponseHead(HttpURLConnection con) "Vx6 #u@}  
{ 6`Lc
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for(int i=1;;i++) >O3IfS(l  
{ V,vc_d?,_o  
String header=con.getHeaderFieldKey(i); Bh,Q8%\6  
if(header!=null) vbaC+AiX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oBC]UL;8xJ  
Utility.log(header+" : "+con.getHeaderField(header)); s*.3ZS5  
else a
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break; i&*<lff  
} 50*@.!^*  
} 2eHx"Ha  
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public void splitterStop() m@[3~ 6A  
{ i?x$w{co  
bStop = true; T6X}Ws"  
} Cx,-_  
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} p(?g-
  
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/* 3e *-\TP-  
**FileAccess.java T0Q51Q  
*//文件访问(定位，写) MO TE/JG  
package NetFox; <%&_#<C)  
import java.io.*; hX3@f;[B2  
Z vRxi&Z{?  
7 OWsHlU  
public class FileAccessI implements Serializable{ # M>wH`Q#  
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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 >:$"a  
RandomAccessFile oSavedFile; x;(g  
long nPos; 3daC;;XO  
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public FileAccessI() throws IOException {mf.!Xev
 
{ }^ ,q#'  
this("",0); =JxFp, Xr  
} O"iak  
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public FileAccessI(String sName,long nPos) throws IOException #D0 ~{H  
{ `O n(v  
oSavedFile = new RandomAccessFile(sName,"rw"); x0ne8NDP  
this.nPos = nPos; hkF^?AJ  
oSavedFile.seek(nPos); D J_DonO]  
} "k, K~@}  
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public synchronized int write(byte[] b,int nStart,int nLen) xl,ryc3J  
{ Y;eoTJ  
int n = -1; Tyd h9I  
try{ 6]ZO'Nwo  
oSavedFile.write(b,nStart,nLen); |6*Va%LYO-  
n = nLen; {=iyK/Uf  
} ?BsH{QRYQ  
catch(IOException e) .1{l[[= W  
{ R;'?;I  
e.printStackTrace (); )qd={  
} CI
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return n; cm,4&x6  
} &mdB\Y?^  
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} O8y9dX-2  
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/* >f%,`r  
**SiteInfoBean.java JhH`uA&  
*/ 3.FR C  
package NetFox; sUV>@UMnu  
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public class SiteInfoBean { UFf,+4q  
#D0W7a  
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private String sSiteURL; //Site's URL &
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private String sFilePath; //Saved File's Path [S)G$JW  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File 5us^B8Q  
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public SiteInfoBean() 5{>>,pP&  
{//nSplitter的缺省值为5 fp tIc#4  
//default value of nSplitter is 5 @(){/
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this("","","",5); KC]tY9 FK  
} H0+:XF\M  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b}}y=zO|$  
{ v8  
sSiteURL= sURL; \OA L Or  
sFilePath = sPath; _Fxe|"<^  
sFileName = sName; zb?kpd}r  
this.nSplitter = nSpiltter; 69iM
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} ? oc+ 1e  
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public String getSSiteURL() I{EIHD<  
{ m3luhGn  
return sSiteURL; AA2ui%  
} y{9
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public void setSSiteURL(String value) Pa
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{ p+)C$2YK  
sSiteURL = value; #@E(<Pu4`  
} 2m_H*1HJ  
0mVuD\#=!  
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public String getSFilePath() 0Nt%YP  
{ .*:h9AE7vo  
return sFilePath; |,{+;:  
} 8m|x#*5fQl  
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public void setSFilePath(String value) 7PA=)a\  
{ "*t6t4/Q  
sFilePath = value; (rIXbekgB  
} H>Ks6V)RL4  
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public String getSFileName() cCk1'D|X[e  
{ p
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return sFileName; 8:<1|]]  
} jzQ I>u  
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public void setSFileName(String value) WkP|4&-<  
{ %_)b>C18y  
sFileName = value; 7BS/T  
} <\p&jk?  
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public int getNSplitter() qhnapZJ  
{ .01TTK*  
return nSplitter; y+
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} }-dF+m:  
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public void setNSplitter(int nCount) D"'#one  
{ Rn8#0%/Q  
nSplitter = nCount; ^>eFm8`N  
} Nl=+.d6Qo  
} +yvBSpY  
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/* #|q;t   
**Utility.java ,rXW`7!2  
*/ bu;vpNa  
package NetFox; ]Px:d+wX:  
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public class Utility { R4yJ.f  
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public Utility() ,I=O"z>9  
{ 6B /Jp  
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} c'SM>7L  
/1U,+g^O>  
//线程睡眠 aQC7V!v  
public static void sleep(int nSecond) E|\3f(aF  
{ V`U/'N-ay  
try{ ;B(;2.<"J  
Thread.sleep(nSecond); E#m76]vkCU  
} L{zamVQG  
catch(Exception e) e_\SSH@tw  
{ i;gw=Be  
e.printStackTrace (); -g~iE]x6Y  
} VB}PNg  
} s9=pV4fA~w  
O$YJku  
//日志 5QNBB|X@  
public static void log(String sMsg) =xl7vHn7  
{ ?NQD#  
System.err.println(sMsg); 6CCZda@  
} +HYN$>  
*'s&/vEy  
+W!'B
r  
public static void log(int sMsg) [qq`cT@  
{ dV'6m@C
 
System.err.println(sMsg); u)wu=z8  
} k:@a[qnY  
} 1i ?gvzrq  
 j@s=ER  
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/* G;87in ,}  
**TestMethod.java 2nVuz9h  
*/ 9(V=Ubj  
package NetFox; +*WUH513  
HrM)jC<~  
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public class TestMethod {  zgZi  
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K#%O3RRs  
public TestMethod() qFB9,cUqh  
{ ///xx/weblogic60b2_win.exe 9_I[o.q   
try{ o<9yaQ;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _gis+f/8h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 94S .9A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $@XPL~4  
fileFetch.start(); 56/.*qa  
} N^)<)?  
catch(Exception e){e.printStackTrace ();} 7/$nA<qM  
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;))[P_$zB  
} :T8u?@.  
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public static void main(String[] args) f]O5V$!RuE  
{ Te{aB"B  
new TestMethod(); ^R&_}bp  
} <T4 7kLI  
} 1mvu3}ewx  
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