http断点续传简单实现（java)

/* qcR|E`k-G  
**SiteFileFetch.java c4!c_a2pS  
*/ Fi,e}j=2f  
package NetFox; XhHel|!g:  
import java.io.*; Ba"^K d`  
import java.net.*; {ar5c&<  
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public class SiteFileFetch extends Thread { ~#HH;q_7m  
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SiteInfoBean siteInfoBean = null; //文件信息Bean knNhN=hG+  
long[] nStartPos; //开始位置 !0>!tW  
long[] nEndPos; //结束位置 L@gQ L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 35]j;8N:  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 Mhu53DT  
boolean bStop = false; //停止标志 P;HVLflu  
File tmpFile; //文件下载的临时信息 al3BWRq'f  
DataOutputStream output; //输出到文件的输出流 +
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l`~a}y"n  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z>>gXh<e[  
{ 8|S1|t,  
siteInfoBean = bean; FcA)RsMI*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Qwp\)jVi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -@gJqoo>  
if(tmpFile.exists ()) 1`2);b{@  
{ Tb!B!m  
bFirst = false; hB2s$QS  
read_nPos(); iECC@g@a  
} q>D4m
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else &F<J#cfe8  
{ " kE:T.,  
nStartPos = new long[bean.getNSplitter()]; Tv*1q.MB  
nEndPos = new long[bean.getNSplitter()]; 1{\,5U&  
} BM=V,BZy  
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} X1 0"G~0  
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public void run() n!CP_  
{ t9$AvE#a!=  
//获得文件长度 ]sm0E@1  
//分割文件 Y7b,td1  
//实例FileSplitterFetch cW~6@&
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//启动FileSplitterFetch线程 ]$?zT`>(F  
//等待子线程返回 m"?'hR2  
try{ ||
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if(bFirst) A^= Hu,"
e  
{ U:pLnNp`  
nFileLength = getFileSize(); Vx\#+)4  
if(nFileLength == -1) C,VqT6E<  
{ O_s9  
System.err.println("File Length is not known!"); Y|x6g(b  
} WW8YB"  
else if(nFileLength == -2) 6/V{>MTZg  
{ b
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System.err.println("File is not access!"); xRTg [  
} l b1sV  
else r=P$iG'&  
{ 9`gGsC  
for(int i=0;i<nStartPos.length;i++) !7,K9/"  
{ @6I[{{>X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Jq?^8y  
} S7#^u`'Q_^  
for(int i=0;i<nEndPos.length-1;i++) LfjS[  
{ J7
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nEndPos = nStartPos[i+1]; UtGd/\:  
} mn6p s6OB  
nEndPos[nEndPos.length-1] = nFileLength; F|n$0vQ*  
} [V#&sAe  
} 8G[Y9A(bmP  
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w'!}(Z5X?  
//启动子线程 0t:|l@zB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G7kFo6Cb  
for(int i=0;i<nStartPos.length;i++) 6!Tf'#TV~!  
{ 5f^`4pT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \.{pZMM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5@%=LPV  
nStartPos,nEndPos,i); g:HbmXOBpj  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $Zu4tuXA  
fileSplitterFetch.start(); 2AdHj&XE  
} zm)CfEF 8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UNZVu~WnF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h?pGw1Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sVm'9k  
nEndPos = " + nFileLength); l`5}i|4KTW  
// fileSplitterFetch[nPos.length-1].start(); loqS?bC]  
n.H`1@  
$Bwvw)(%  
//等待子线程结束 gQ+_&'C  
//int count = 0; -"JE-n  
//是否结束while循环 hoD[wAC  
boolean breakWhile = false; GF.g'wYc)Y  
{*=5qV}  
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while(!bStop) 0?4^.N n3  
{ J<P/w%i
2  
write_nPos(); @1qUC"Mg  
Utility.sleep(500); t"74HZO>  
breakWhile = true; )dN,b(w9  
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for(int i=0;i<nStartPos.length;i++) ]I*#R9  
{ |sZ9/G7  
if(!fileSplitterFetch.bDownOver)  q&Ua(I  
{ Rx"VscB6z  
breakWhile = false; CYic_rF$  
break; \?mU$,voI  
} MvjwP?J]  
} +P6  
if(breakWhile) m5Laq'~0_  
break; ,vY I O  
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//count++; T6?d`i i1  
//if(count>4) 6V_5BpXt  
// siteStop(); RkXLE"G'  
} 'w$we6f  
b8-^wJH!  
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System.err.println("文件下载结束！"); Ei(`gp  
} _q!ck0_  
catch(Exception e){e.printStackTrace ();} GMp'KEQQ  
} ^~kFC/tQ  
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//获得文件长度 PL B=%[  
public long getFileSize() U?m?8vhR6(  
{ K]azUK7  
int nFileLength = -1; ^J=txsx  
try{ sAAIyPJts  
URL url = new URL(siteInfoBean.getSSiteURL()); &7y1KwfXn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Qm{\  
httpConnection.setRequestProperty("User-Agent","NetFox"); ' xq5tRg>  
`];[T=  
9(Xch2tpO!  
int responseCode=httpConnection.getResponseCode(); Fl(ZKpSZU  
if(responseCode>=400) 5TW<1'u  
{ $G([#N<  
processErrorCode(responseCode); gmH0-W)=  
return -2; //-2 represent access is error HE.Dl7{  
} \Hx#p`B%  
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String sHeader; KE1@z]  
]tV{#iIJ*  
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for(int i=1;;i++) ^Q+5M"/8  
{ @ShJ:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9Yne=R/]  
//Utility.log(in.readLine()); {y%O_-C'r  
sHeader=httpConnection.getHeaderFieldKey(i); GnHf9 JrR  
if(sHeader!=null) W${sD|d-  
{ BHBR_7  
if(sHeader.equals("Content-Length")) KD<`-b)7<  
{ JZ0+VB-3U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^rb7`s#G  
break; R_&V.\e_  
}
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} \evgDZf  
else
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break; \nt'I;f  
} WED7]2>  
} Ho{?m^  
catch(IOException e){e.printStackTrace ();} lt2&uYgp  
catch(Exception e){e.printStackTrace ();} -BH'.9uqGQ  
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Utility.log(nFileLength); 78A4n C  
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return nFileLength; ^HKaNk<  
} _'v )Fy  
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//保存下载信息（文件指针位置） 3Jit2W4  
private void write_nPos() Eu_0n6J  
{ C/#/F#C  
try{ :7]R2J
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output = new DataOutputStream(new FileOutputStream(tmpFile)); BU .G~0  
output.writeInt(nStartPos.length); M4]|(A  
for(int i=0;i<nStartPos.length;i++) 1Ee>pbd  
{ ov}{UP]a?  
// output.writeLong(nPos); l1j   
output.writeLong(fileSplitterFetch.nStartPos); Cf 8-%  
output.writeLong(fileSplitterFetch.nEndPos); J8[Xl.  
} dTNgrW`4  
output.close(); ITOGD  
} ?7dDQI7^(  
catch(IOException e){e.printStackTrace ();} l)eaIOyk  
catch(Exception e){e.printStackTrace ();} 2Nszxvq,  
} K1yM'6Zw  
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//读取保存的下载信息（文件指针位置） SQRz8,sqkw  
private void read_nPos() +4RaN`I  
{ RozsRt;i  
try{ 2^j9m}`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $:P~21,  
int nCount = input.readInt(); cA^7}}?e  
nStartPos = new long[nCount]; QpZhxp  
nEndPos = new long[nCount]; 0 N^V&k   
for(int i=0;i<nStartPos.length;i++) D{}\7qe  
{ eS+LFS7*k  
nStartPos = input.readLong(); T{Q&}`D)r  
nEndPos = input.readLong(); mQ)l`
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} #@`^ .  
input.close(); aesFv)5DK  
} BF#e=p  
catch(IOException e){e.printStackTrace ();} |8rJqtf +&  
catch(Exception e){e.printStackTrace ();} Yf9L~K  
} W12K93tO  
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private void processErrorCode(int nErrorCode) l#:Q V:  
{ r#}%sof  
System.err.println("Error Code : " + nErrorCode); mcracj[B  
} sRG3`>1  
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6C5qW8q]u3  
//停止文件下载 %?y`_~G  
public void siteStop() [!$>:_Vq/  
{ c}cboe2  
bStop = true; /267Q;d C)  
for(int i=0;i<nStartPos.length;i++) EORAx  
fileSplitterFetch.splitterStop(); w, wt<@}  
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} Sn,z$-;h;  
} Rx<F^J
 
//负责部分文件的抓取 NoIdO/vy"  
**FileSplitterFetch.java P$yJA7]j;%  
*/ 1gr jK.x  
package NetFox; gr7_oJ:R  
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import java.io.*; oE&[W>,x  
import java.net.*; C,rZ}-  
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public class FileSplitterFetch extends Thread { ]vrs?  
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String sURL; //File URL lX7^LB  
long nStartPos; //File Snippet Start Position &3. 8i%  
long nEndPos; //File Snippet End Position v|z1nD!?]  
int nThreadID; //Thread's ID ,%^0 4sl  
boolean bDownOver = false; //Downing is over ZvJx01F{  
boolean bStop = false; //Stop identical jTIn@Q  
FileAccessI fileAccessI = null; //File Access interface H9?~#GPb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l+,rc*-j0  
{ X35hLp8 M  
this.sURL = sURL; Z5K,y19/~  
this.nStartPos = nStart; [%y D,8  
this.nEndPos = nEnd; G_@H:4$3  
nThreadID = id; \~>#<@h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UK/k?0  
} C09@2M'  
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public void run() AnQRSB
(  
{ #e[5O|V~  
while(nStartPos < nEndPos && !bStop) P[~a'u  
{ rjzRH  
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try{ }ls>~uN  
URL url = new URL(sURL); }^t?v*kcA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5q[@N J  
httpConnection.setRequestProperty("User-Agent","NetFox"); uNjy&I:  
String sProperty = "bytes="+nStartPos+"-"; Q]C1m<x  
httpConnection.setRequestProperty("RANGE",sProperty); ijfT!W  
Utility.log(sProperty); K[H$qJmPX  
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InputStream input = httpConnection.getInputStream(); %!RQ:?=  
//logResponseHead(httpConnection); lDzVc`c  
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byte[] b = new byte[1024]; f32nO
 
int nRead; ]2+(i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M*Xzr .6  
{ BH^q.p_#>X  
nStartPos += fileAccessI.write(b,0,nRead); 9b>a<Z  
//if(nThreadID == 1) (msJ:SG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .W\Fa2}%av  
} Om*Dy}  
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Utility.log("Thread " + nThreadID + " is over!"); P_}$|zj7  
bDownOver = true; FK>rc3 q  
//nPos = fileAccessI.write (b,0,nRead); Zx6BK=4G  
} B(hNBq7  
catch(Exception e){e.printStackTrace ();} |dO1w.x/  
} G9jtL$}E<  
} ]4PG[9J@  
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//打印回应的头信息 BTB,a$P/  
public void logResponseHead(HttpURLConnection con) JkTL+obu  
{ rz(DZV  
for(int i=1;;i++) gg=z.`}  
{ 98l#+4+  
String header=con.getHeaderFieldKey(i); '`n\YO.N  
if(header!=null) U}NNbGQj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >i'3\  
Utility.log(header+" : "+con.getHeaderField(header)); l\H9Io3  
else Z=ho7i  
break; TAP/gN'  
} Rh39x-`Z  
} aX!J0
&3  
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/ wEr>[8S  
public void splitterStop()  )57OZ  
{ 0W@C!mD~  
bStop = true; `KZ}smMA  
} r~X6qC  
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} wx<DzC  
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/* qzq>C"z\Y$  
**FileAccess.java u >x2  
*//文件访问(定位，写) R]dc(D  
package NetFox; U7O2.y+  
import java.io.*; A\:M}D-(  
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public class FileAccessI implements Serializable{ 6;ICX2Wq'  
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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 o9JJ_-O"  
RandomAccessFile oSavedFile; }a8N!g  
long nPos; 27)$;1MT:  
l-5-Tf&j  
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public FileAccessI() throws IOException ^#;2 Pd>  
{  7p{lDQ  
this("",0); .S[5CO^  
} :iq1-Pw  
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public FileAccessI(String sName,long nPos) throws IOException lgU7jn  
{ H}A67J9x  
oSavedFile = new RandomAccessFile(sName,"rw"); Oa{M9d,l  
this.nPos = nPos; ]^dXB0  
oSavedFile.seek(nPos); ?(F~9V  
} Xf
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public synchronized int write(byte[] b,int nStart,int nLen) Fm:Ri$iT  
{ g8^$,  
int n = -1; qz?9:"~$C  
try{ k9a-\UIMet  
oSavedFile.write(b,nStart,nLen); $H?v  
n = nLen; 
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} e<q;` H  
catch(IOException e) %ePInpb  
{ th !Gc  
e.printStackTrace (); RE*;nSVFt  
} wqJH  
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return n; +YXyfTa  
} *PD7H9m  
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} pX"f "  
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/* IpHGit28  
**SiteInfoBean.java (tys7og$'  
*/ tM
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package NetFox; 5s8k^n"A  

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public class SiteInfoBean { UkeX">  
64Q{YuI  
rcAx3AK.  
private String sSiteURL; //Site's URL K-#v5_*  
private String sFilePath; //Saved File's Path pf[bOjtR  
private String sFileName; //Saved File's Name k]w;(<  
private int nSplitter; //Count of Splited Downloading File 8H;yrNL  
tK1P7pbC8r  
j%0D:jOY]  
public SiteInfoBean() PU[] Nw  
{//nSplitter的缺省值为5 3(jI  
//default value of nSplitter is 5 cJGU~\  
this("","","",5); 4;y*y tY*  
} =56O-l7T*w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kect)=T(  
{ 0"LJ{:plz  
sSiteURL= sURL; 5@6F8:x}V  
sFilePath = sPath; U%_BgLwy%  
sFileName = sName; WQK ~;GV-  
this.nSplitter = nSpiltter; 7;5SK:X%dm  
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d=yuuS/  
} 22(7rUkI  
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public String getSSiteURL() u8 Q`la  
{ M:rE^El  
return sSiteURL; &( aw  
} .7_<0&kW  
3vepJ)D (  
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public void setSSiteURL(String value) D.su^m_1  
{ R0HzNk  
sSiteURL = value; ,Y ./9F  
} [2ez"4e  
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public String getSFilePath() lp+Uox  
{ }fU"s"  
return sFilePath; Lk#8G>U  
} "V'<dn  
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public void setSFilePath(String value) K!g!tA$  
{ Cj'XL}  
sFilePath = value; zsOOx% +  
} b*Sw")#  
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public String getSFileName() ';'gKX
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{ }6b" JoC  
return sFileName; j2^Vz{  
} yGj'0c::  
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public void setSFileName(String value) |q!O~<H@  
{ QN)EPS:y  
sFileName = value; Q!.JV.(  
} ^Q,-4\ec  
V96:+r  
[`(W(0U%  
public int getNSplitter() 3'2>3Y/7Bb  
{ `cgyiJ  
return nSplitter; sYa;vg4[  
} <Ukeq0  
rJtpTV@.  
s`#g<_{X  
public void setNSplitter(int nCount) jEu-CU#:  
{ o&-D[|E|  
nSplitter = nCount; <!;NJLe`  
} r?7tI0  
} {?X:?M_  
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tK7v&[cI  
/* wjy<{I  
**Utility.java ]Ub"NLYV  
*/ b=+3/-d  
package NetFox; T$!Pkdh  
 9q[d?1  
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public class Utility { ;
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public Utility() N||a0&&  
{ lq}m0}9<  
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} Bi-x gq'z  
.VXadgM  
//线程睡眠 pddumbp  
public static void sleep(int nSecond) =[do([A  
{ aE(DNeG-H  
try{ <5O:jd  
Thread.sleep(nSecond); P1_6:USBM  
} &[b(Lx|i  
catch(Exception e) t9~Y ?  
{ s7?d_+O  
e.printStackTrace (); #KUNZW  
} XcFu:B  
} 'IQ;;[Q  
!,<rW<&;  
//日志 fD<0V  
public static void log(String sMsg) A=96N@m6  
{ +k;][VC[O  
System.err.println(sMsg); zD@RW<M  
} NjFlV(XT}  
]kdU]}z  
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public static void log(int sMsg) gY {/)"
 
{ U_sM==~  
System.err.println(sMsg); }Jo}K)>!  
} fA)4'7UT  
} Ex<@:  
yYH>~,  
w!r.MWE  
/* !ZS5}/ZU  
**TestMethod.java L'HO"EZFj  
*/ h9Tst)iRi  
package NetFox; e'X"uH Xt.  
Z6fR2A~Q[  
o*5b]XWw  
public class TestMethod { /lLG
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4Q(w D  
Lvb'qZ6n  
public TestMethod() Bo4iX,zu  
{ ///xx/weblogic60b2_win.exe L"L a|  
try{ +WE<S)z<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8;i
'dF:)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @NYlVk2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jwp?eL!7  
fileFetch.start(); Y;=GM:*H  
} !-Uq#Ea0/  
catch(Exception e){e.printStackTrace ();} 2m,t<Y;  
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!DBaC%TGC  
} ^Sc48iDc  
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GrA}T`]  
public static void main(String[] args)
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{ m!WDXt  
new TestMethod(); 2Uy}#n|)r  
} V!f' O@p[  
} @4wN-T+1  
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