http断点续传简单实现（java)

/* i`nw"8  
**SiteFileFetch.java '-]BSU  
*/ qddT9U|8~  
package NetFox; %V1T!<  
import java.io.*; j% USu+&  
import java.net.*; 8(/f!~  
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07"Oj9NlA  
public class SiteFileFetch extends Thread { W]}V<S$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !@Vp Bl  
long[] nStartPos; //开始位置 -zLI!F 0  
long[] nEndPos; //结束位置 {i}Q}OgYq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ftU5A@(T  
long nFileLength; //文件长度 Hr*Pi3dSI  
boolean bFirst = true; //是否第一次取文件 YB3=ij!K  
boolean bStop = false; //停止标志 <d&)|W  
File tmpFile; //文件下载的临时信息 W>wi;Gf#  
DataOutputStream output; //输出到文件的输出流 2-c0/?_4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） H'\EA(v+  
public SiteFileFetch(SiteInfoBean bean) throws IOException bl>b/u7/6  
{ g?AqC  
siteInfoBean = bean; {5IG3'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y4qyy\}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JIKxY$GS  
if(tmpFile.exists ()) ZpctsCz]  
{ J'c9577$  
bFirst = false; 5"~^;O  
read_nPos(); HgATH  
} sfPN\^k2  
else 71&+
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{ 49fq6ZhO  
nStartPos = new long[bean.getNSplitter()]; <m:wuNEM  
nEndPos = new long[bean.getNSplitter()]; M*6@1.n  
} LbbQ3$@WD  
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} xy3
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public void run() .);:K  
{ O:p649A  
//获得文件长度 AX RNV  
//分割文件 }/r
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//实例FileSplitterFetch _:p_#3s$  
//启动FileSplitterFetch线程 }Y ];ccT  
//等待子线程返回 tRBK1h  
try{ l'%R^  
if(bFirst) ^|;4/=bbs  
{ R./6Q1  
nFileLength = getFileSize(); {1DYXKe
 
if(nFileLength == -1) jF_I4
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{ c+/C7C o  
System.err.println("File Length is not known!"); iQ"F`C  
} ~WXxVm*@  
else if(nFileLength == -2) F/>Pvq]  
{ ^tcBxDC"]  
System.err.println("File is not access!"); azc:C  
} Hbc&.W;g7[  
else +##I4vP  
{ Bic { H  
for(int i=0;i<nStartPos.length;i++) X hX'*{3k  
{ 0%NI- Zyo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VDY1F_Fk  
} :Rj,'uH+h)  
for(int i=0;i<nEndPos.length-1;i++) {leG~[d  
{ &)jZ|Q~  
nEndPos = nStartPos[i+1]; .{Oq)^!ot  
} 4H)"d  
nEndPos[nEndPos.length-1] = nFileLength; r['C.S6  
} 6|cl`}g_j  
} DJ0T5VE W3  
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//启动子线程 E2kRt'~N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G@!9)v]9  
for(int i=0;i<nStartPos.length;i++) 1^^D :tt  
{ S Tk#hhx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >D62l*VC)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1tz .e\  
nStartPos,nEndPos,i); 1u+(rVQN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (r\h dLX  
fileSplitterFetch.start(); MXV4bgltT  
} P[8N58#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nn%xN\~<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D~&e.y/gHN  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &~f_1<  
nEndPos = " + nFileLength); bR,Iq}p  
// fileSplitterFetch[nPos.length-1].start(); JhIK$Ti  
p;=(-4\V}  
(k&aD2PH  
//等待子线程结束 0*@S-Lj^c  
//int count = 0; gj X1b
2  
//是否结束while循环 5K~6`  
boolean breakWhile = false; Ib2pV2`h(  
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while(!bStop) *=@pdQkR  
{ 0|;=mYa4M  
write_nPos(); 8:fiO|~%  
Utility.sleep(500); K.m[S[cy  
breakWhile = true; mDfWR  
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for(int i=0;i<nStartPos.length;i++) TeqsP1{?  
{ j~q`xv+
R  
if(!fileSplitterFetch.bDownOver) Mwc3@  
{ {2@96o2}  
breakWhile = false; _I4sy=tYXK  
break; q:.BY}X9  
} dxWw%_Q  
} = g}yA=.  
if(breakWhile) G].KJ5,y  
break; oD\+ 5[x  
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//count++; nVzo=+Yp  
//if(count>4) '7s!NF2  
// siteStop(); 54w-yY  
} Lai"D[N  
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System.err.println("文件下载结束！"); IhLfuyFWu  
} 0aWb s$FyU  
catch(Exception e){e.printStackTrace ();} C<>.*wlp=  
} `f]O  
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//获得文件长度 q3`t0eLZ  
public long getFileSize() o:<3n,T  
{ ^dv>n]?  
int nFileLength = -1; 7<D_ h/WV  
try{ y{JkY\g  
URL url = new URL(siteInfoBean.getSSiteURL()); F}>`3//u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BYU.ptiJJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xk'.t|  
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int responseCode=httpConnection.getResponseCode(); a0.XJR{T"  
if(responseCode>=400) mN02T@R-  
{ za7wNe(s  
processErrorCode(responseCode);
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return -2; //-2 represent access is error W6Pg:Il7  
} C.<4D1}P  
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@  
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String sHeader; :xCobMs_/  
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for(int i=1;;i++) fF%r$`2  
{ jQ*Qh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~55>uw<  
//Utility.log(in.readLine()); 'oG'`ED"  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) dp_q:P4;B  
{ soF^G21N  
if(sHeader.equals("Content-Length")) g 7X>i:  
{ ,dBI=D'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m='OnTeOE  
break; 4<|u~n*JF  
} {SV$fl;  
} G<'S  
else -eTGRr  
break; JK4 @  
} 7(H/|2;-d8  
} zYgLGwi{  
catch(IOException e){e.printStackTrace ();} zeX?]@]Y  
catch(Exception e){e.printStackTrace ();} GCHssw~P'v  
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Utility.log(nFileLength); P6Ei!t,>  
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return nFileLength; V QI7lJV"  
} Dg`W{oj  
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L
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//保存下载信息（文件指针位置） (C&f~U  
private void write_nPos() lV
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{ UWI5/R  
try{ I8y\D,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8CCA/6  
output.writeInt(nStartPos.length); 1Q<a+ l  
for(int i=0;i<nStartPos.length;i++) i&Ea@b  
{ eo!z>9#.  
// output.writeLong(nPos); BeQJ/`  
output.writeLong(fileSplitterFetch.nStartPos); zx27aZ[  
output.writeLong(fileSplitterFetch.nEndPos); 3?:}lY<,  
} A Ho<E"R\  
output.close(); <$E8T>U  
} M5]wU   
catch(IOException e){e.printStackTrace ();} R-ci?7dt3  
catch(Exception e){e.printStackTrace ();} /-T%yuU  
} R##O9BSI8Z  
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//读取保存的下载信息（文件指针位置） 7DDot_qb  
private void read_nPos() $\H>dm  
{ 3I]5DW %-  
try{ ]#`bYh^y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H X8q+  
int nCount = input.readInt(); VrpYBU  
nStartPos = new long[nCount]; BtspnVBez  
nEndPos = new long[nCount]; q6q=,<T%S  
for(int i=0;i<nStartPos.length;i++) 7 UR)4dYA  
{ `g7' )MSy  
nStartPos = input.readLong(); q07>FW R  
nEndPos = input.readLong(); ;RXv%ML  
} [yz;OoA:;  
input.close(); m9/a!|fBE  
} Mvux=Ws  
catch(IOException e){e.printStackTrace ();} H_9~gi  
catch(Exception e){e.printStackTrace ();} E)Dik`Ccl  
} 1*Z}M%  
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private void processErrorCode(int nErrorCode) @I%m}>4Jm  
{ b+kb7  
System.err.println("Error Code : " + nErrorCode); X:YxsZQ5Y  
} E>&dG:3no  
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//停止文件下载 I)clGMS,  
public void siteStop() NFQ0/iuW  
{ l
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bStop = true; FkH4|}1  
for(int i=0;i<nStartPos.length;i++) xaPTTa  
fileSplitterFetch.splitterStop(); 1*XqwBV  
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} mWZVO,t$  
}  A/9 wr  
//负责部分文件的抓取 H=0Y4 T@)T  
**FileSplitterFetch.java [.2>=3T  
*/ fSj^/>  
package NetFox; f.!cR3XgV  
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import java.io.*; 0'gJSrgNI  
import java.net.*; JWLQ9UX  
;(z0r_p<q  
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public class FileSplitterFetch extends Thread { iKu5K0x{>I  
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String sURL; //File URL C3|M\[*fp  
long nStartPos; //File Snippet Start Position xk#/J]j  
long nEndPos; //File Snippet End Position kc}e},k  
int nThreadID; //Thread's ID VP[ J#TPU  
boolean bDownOver = false; //Downing is over 4]Krx m`8  
boolean bStop = false; //Stop identical C@xh$(y  
FileAccessI fileAccessI = null; //File Access interface 86[TBX5'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1g *4e  
{ J 9z\ qTI  
this.sURL = sURL; 0 ~VniF^  
this.nStartPos = nStart; ^*Sb)tu\ W  
this.nEndPos = nEnd; 0 j6/H?OT  
nThreadID = id; ^X^4R1V)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zT.qNtU%  
} U`xjau+  
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public void run() $cc]pJy"}  
{ QHK$2xtq|  
while(nStartPos < nEndPos && !bStop) )8yNqnD  
{ B&cC;Hw  
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try{ `C,479~J  
URL url = new URL(sURL); #5F\zeo@F?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $cnIsyKWY  
httpConnection.setRequestProperty("User-Agent","NetFox"); 60Y&)UR  
String sProperty = "bytes="+nStartPos+"-"; O.}{s;  
httpConnection.setRequestProperty("RANGE",sProperty); ;'*"(F=D6  
Utility.log(sProperty); @Kp2l<P  
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InputStream input = httpConnection.getInputStream(); Q1g@FsW&U  
//logResponseHead(httpConnection); M*|x,K=U  
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byte[] b = new byte[1024]; 9|fg\C  
int nRead; .^ so
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =}F &jl  
{ s~,Ypo?  
nStartPos += fileAccessI.write(b,0,nRead); K%.\@l2Cp  
//if(nThreadID == 1) =j6f/8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Eb[*nWF=  
} }!x\qpA  
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Utility.log("Thread " + nThreadID + " is over!"); 4Z,MqG>  
bDownOver = true; M#UW#+*g!  
//nPos = fileAccessI.write (b,0,nRead); lo Oh }y+  
} NZ7g}+GTG  
catch(Exception e){e.printStackTrace ();} ,!Gw40t  
} abp]qvCV  
} CtfI&rb[  
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//打印回应的头信息 <`}Oi5nW  
public void logResponseHead(HttpURLConnection con) 1Jjay#  
{ E)7vuWOO  
for(int i=1;;i++) 9t9x&.A  
{ /^SIJS@^`>  
String header=con.getHeaderFieldKey(i); CNwIM6
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if(header!=null) ;N#d'E\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qS:hv&~  
Utility.log(header+" : "+con.getHeaderField(header)); -W<x|ph U  
else Yxp.`  
break; QX-%<@  
} ?#da4W  
} {1Z8cV  
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public void splitterStop() [@(M%  
{ Bvb.N$G  
bStop = true; E<y0;l?H<  
} u_shC"X:  
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}
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/* n]S DpptM  
**FileAccess.java 5[suwaJQ  
*//文件访问(定位，写) L|A}A[P  
package NetFox; M{w[hV  
import java.io.*; `lygJI?H+{  
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public class FileAccessI implements Serializable{ {}RE;5n\['  
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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 6aRPm%  
RandomAccessFile oSavedFile; bis}zv^%v  
long nPos; {xJq F4  
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public FileAccessI() throws IOException Z\c^CN  
{ _$g6Mj]1z  
this("",0); iZm# "}VG  
} 4LO4SYW7  
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public FileAccessI(String sName,long nPos) throws IOException iYJ:P  
{ <?yf<G'$  
oSavedFile = new RandomAccessFile(sName,"rw"); dp;;20z  
this.nPos = nPos; IsP-[0it  
oSavedFile.seek(nPos); trlZ^K  
} #y;TSHx/  
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public synchronized int write(byte[] b,int nStart,int nLen) '9d<vWg  
{ [Ume^  
int n = -1; tjLp;%6e  
try{ \A "_|Yg  
oSavedFile.write(b,nStart,nLen); " ,k(*  
n = nLen; WRIOjQ:  
} #x|x
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catch(IOException e) yR}PC/>  
{ Y%$@ZYW  
e.printStackTrace (); GY%^!r  
} v|~&I%S7  
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return n; F3uR:)4<M  
} Fs+ CY  
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} }MU}-6  
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/* 5~8FZ-x  
**SiteInfoBean.java <=O/_Iu(  
*/ sVzU
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package NetFox; MX*T.TG8  
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public class SiteInfoBean { "!w$7|%T  
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private String sSiteURL; //Site's URL $4YyZ!_.@  
private String sFilePath; //Saved File's Path _T\/kJ)Q\  
private String sFileName; //Saved File's Name Q5K<ECoPk  
private int nSplitter; //Count of Splited Downloading File AlPk o($E*  
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public SiteInfoBean() l rRRRR  
{//nSplitter的缺省值为5 q!fdiv`  
//default value of nSplitter is 5 /i!3Fr"  
this("","","",5); U
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} J)kH$!csi  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $nf5bo/;  
{ g#W/WKvM  
sSiteURL= sURL; s*XE  
sFilePath = sPath; UYw_k\  
sFileName = sName; *HC[LM  
this.nSplitter = nSpiltter; 3P}^Wu  
N*mm[F2+F  
P }BU7`
8  
} fC4#b?Q  
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public String getSSiteURL() Ire+r "am  
{ 6x]x>:8  
return sSiteURL; mKTa.  
} PQ0l<]Y  
,V`zW<8
  
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public void setSSiteURL(String value) %jBI*WzR  
{ '!V5 #J  
sSiteURL = value; (7zdbJX  
} K-<kp!v  
^Fop/\E  
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public String getSFilePath() ,)svSzR  
{ jIvSjlmI  
return sFilePath; dRhsnT+KX  
} j]6c_r3
 
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public void setSFilePath(String value) L!>EW0  
{ HxE`"/~.7k  
sFilePath = value; i!nPiac  
} Le?yzf  
S
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public String getSFileName() bdxmJ9a:R  
{ L/+KY_b:*  
return sFileName; s7 K](T4  
} q8=hUD%5C  
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public void setSFileName(String value) `i"7; _HoV  
{ ^q@6((O  
sFileName = value; )@hG#KMK  
} _T^+BUw  
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public int getNSplitter() rn8#nQ>QZ%  
{ sI,S(VWor  
return nSplitter; _v\L'`bif  
} (\qO~)[0  
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public void setNSplitter(int nCount) sM _m  
{ CS\ E]f  
nSplitter = nCount; =Z~nzyaN  
} _Pe,84Ro  
} }i\U,mH0_&  
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/* WF&?OHf2  
**Utility.java n7$2
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*/ ^{l^Z +b.  
package NetFox; p]^?4  
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public class Utility { cy%S5Rz  
}b$W+/M\  
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public Utility() U%qE=u-  
{ 3B^`xnV  
kCVO!@yZz  
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} I<}<!.Bc!  
?E2$  
//线程睡眠 F?jFFwim  
public static void sleep(int nSecond) QVq+';cG  
{ /t$J<bU  
try{ ch-.+p3  
Thread.sleep(nSecond); qVe&nXo  
} MEled:i  
catch(Exception e) >I&'Rj&Mc  
{ 3{/Y&/\"'^  
e.printStackTrace (); 6 h%%?  
} \[CPI`yQe  
} C\RJ){dk  
2g`<*u*  
//日志 Kc,=J?Ob  
public static void log(String sMsg) i p"LoCE  
{ yr"BeTrS.  
System.err.println(sMsg); wusj;v4C4M  
} QGkMT+A  
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7#G8qh<
 
public static void log(int sMsg) 8 mFy9{M  
{ <,\Op=$l3I  
System.err.println(sMsg); tpQ?E<O  
} 9`8D Ga  
} R32A2Ml  
KN\*|)  
#J_+ SL[  
/* !\(j[d#  
**TestMethod.java %7vjYvo>  
*/ Jp#Onl+d6  
package NetFox; @5tW*:s  
s/cclFji]  
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public class TestMethod { ynQ+yW74Z  
83[gV@LW0m  
:@=;WB*0
 
public TestMethod() a|5^4 J\%  
{ ///xx/weblogic60b2_win.exe >anq1Kf  
try{ u.~`/O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O S%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {!]7=K)W9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R8(Bt73  
fileFetch.start(); +"8-)'  
} OMM5p=2Q  
catch(Exception e){e.printStackTrace ();} >$ok3-tuU  
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} ~;ZT<eCIA  
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public static void main(String[] args) iFBH;O_~  
{ _O w]kP='  
new TestMethod();
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} 3~5%6`  
} 7LZA!3  
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