http断点续传简单实现（java)

/* 0d|DIT#>?  
**SiteFileFetch.java )Vf!U"  
*/ G4;5$YGG  
package NetFox; a\l?7Jr  
import java.io.*; e0z(l/UB  
import java.net.*; 1=@csO_yn  
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3 BQZ[%0@  
public class SiteFileFetch extends Thread { ?se\?q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b4?]/Uy+/  
long[] nStartPos; //开始位置 x@LNjlP  
long[] nEndPos; //结束位置 "tF#]iQQ u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /?Y]wY  
long nFileLength; //文件长度 |MMaaW^"  
boolean bFirst = true; //是否第一次取文件 xg;I::hE7X  
boolean bStop = false; //停止标志 FQh8(^(  
File tmpFile; //文件下载的临时信息 t9eEcqMg  
DataOutputStream output; //输出到文件的输出流 o|V`/sW{  
% B^BN|r  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T B(K&3_D  
public SiteFileFetch(SiteInfoBean bean) throws IOException }.k*4Vw#Wt  
{ 1@:BUE;jZ  
siteInfoBean = bean; Ys@OgdS@:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y a/+|mv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dMw}4c3E  
if(tmpFile.exists ()) Liv.i;-qE  
{ /6{P ?)]pE  
bFirst = false; aN?^vW<  
read_nPos(); +R2+?v6  
} 90Bn}@t=Q  
else S Rb-eDk'  
{ 5q,ZH6\ {  
nStartPos = new long[bean.getNSplitter()]; s1>d)2lX  
nEndPos = new long[bean.getNSplitter()]; "&%Lhyt  
} &WKAg:^k)  
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} wx*03(|j;  
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public void run() 5V*R
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{ JUCp#[q  
//获得文件长度 &dky_H  
//分割文件 6o)RsxN eu  
//实例FileSplitterFetch 3lsfT-|Wt&  
//启动FileSplitterFetch线程 )]tf|Mbu  
//等待子线程返回 S;^'Ek"Z.  
try{ gwyX%9  
if(bFirst) @j<Q2z^  
{ {\vcwMUzZ  
nFileLength = getFileSize(); z'&tmje[?  
if(nFileLength == -1) "lRxatM  
{ e'|IRhr  
System.err.println("File Length is not known!"); \C<'2KZR,  
} {|B 2$1':  
else if(nFileLength == -2) S| |OSxZ  
{ 0[ZB^  
System.err.println("File is not access!"); j8)rz  
} Oq*;GR(Q  
else Oy_%U*  
{ | Di7,$c  
for(int i=0;i<nStartPos.length;i++) -&EU#Wqh  
{ A5E^1j}h@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 
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} `-w,6  
for(int i=0;i<nEndPos.length-1;i++) 2jF}n*[OW  
{ 8ByNaXMO6  
nEndPos = nStartPos[i+1]; u<JkP <"S  
} x~QZVL=:  
nEndPos[nEndPos.length-1] = nFileLength; ntQW+!s
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} /:@)De(S  
} 6~OJB!  
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//启动子线程 -Q6Vz=ku  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  ]&OI.p  
for(int i=0;i<nStartPos.length;i++) *?pnTQs^  
{ 88KQ) NU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^c]c`w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ns#v?D9NF  
nStartPos,nEndPos,i); t|m=X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K5HzA1^  
fileSplitterFetch.start(); H`s[=Y,m  
} ws<pBC,m  
// 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); [jR>.H'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0Ibe~!EiQJ  
nEndPos = " + nFileLength); u7SC_3R  
// fileSplitterFetch[nPos.length-1].start(); Rn*@)5  
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//等待子线程结束 .I0M'L~!/L  
//int count = 0; 3el/,v|qj  
//是否结束while循环 !l5@L\  
boolean breakWhile = false; sIMN""@Y^  
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while(!bStop) y3':x[d  
{ S$=caZ?  
write_nPos(); J1w,;T\55  
Utility.sleep(500); seVT|z  
breakWhile = true; 5<M$ XT  
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for(int i=0;i<nStartPos.length;i++) RI<&cgWn+<  
{ R*?!xDJ  
if(!fileSplitterFetch.bDownOver) ^Y%<$I
FG  
{ -"EPU]q  
breakWhile = false; vdh[%T,&  
break; #^tnRfS"  
} %]1te*_  
} t&i4kS^y  
if(breakWhile) |\xTcS|d  
break; >abpse  
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//count++; ?<
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//if(count>4) a ?\:,5=  
// siteStop(); H43d[@h  
} Z<*"sFpAO  
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System.err.println("文件下载结束！"); J!}\v=Rn  
} 2UIZ<#|D>s  
catch(Exception e){e.printStackTrace ();} fWf't2H&  
} \]g51U!'  
+6x}yc:yd  
+,Or^pO=  
//获得文件长度 _gEojuaN  
public long getFileSize() _U9.u#>sV  
{ Jpc%i8  
int nFileLength = -1; /A+5q\8G  
try{ /Ny#+$cfk  
URL url = new URL(siteInfoBean.getSSiteURL()); hj\A-Yf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bYmk5fpRG  
httpConnection.setRequestProperty("User-Agent","NetFox"); pgs<Mo$\%B  
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int responseCode=httpConnection.getResponseCode(); SW5n?Qj3-  
if(responseCode>=400) >[&ser  
{ p(cnSvg  
processErrorCode(responseCode); E.*gKfL  
return -2; //-2 represent access is error ^%m{yf#  
} w}s5=>QG%  
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String sHeader; 3.9/mztS  
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for(int i=1;;i++) mM~&mAa+Z  
{ JmeE}:5lpj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A%X=yqY  
//Utility.log(in.readLine()); #M<YNuE#"  
sHeader=httpConnection.getHeaderFieldKey(i); F'"-aB ~  
if(sHeader!=null) S;u.Ds&  
{ HCx0'|J  
if(sHeader.equals("Content-Length")) 8Zy*#[-  
{ hgbf"J6V8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _pzYmQ  
break; Igw2n{})w  
} 4TyzD%pOw  
} {?q`9[Z  
else B%`|W@v  
break; .V\~#Ro$G  
} s:cJF  
} #K*p1}rf  
catch(IOException e){e.printStackTrace ();} Z78i7k}  
catch(Exception e){e.printStackTrace ();} Sy]W4%  
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Utility.log(nFileLength); 2b
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return nFileLength; tc{l?7P  
} NJmx(!Xsh  
vE1:;%Q  

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//保存下载信息（文件指针位置） SrGJ#K&%  
private void write_nPos() L,!\PV|  
{ 0d+b<J,  
try{ _ nz^+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @=2u;$.  
output.writeInt(nStartPos.length); Hzc}NyJ  
for(int i=0;i<nStartPos.length;i++) }x&XvI  
{ }gFa9M<  
// output.writeLong(nPos); b4EUrSL  
output.writeLong(fileSplitterFetch.nStartPos); Y+kuj],h  
output.writeLong(fileSplitterFetch.nEndPos); `t44.=%  
} Y^C(<
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output.close(); 2 E?]!9T~|  
} Y]Z&  
catch(IOException e){e.printStackTrace ();} 2Nx:Y+[  
catch(Exception e){e.printStackTrace ();} 9P,[MZ  
} JG&E"j#q  
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//读取保存的下载信息（文件指针位置） 2Dt^W.!  
private void read_nPos() N"tX K  
{ ^uphpABpD  
try{ >;F}>_i  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5q'b M  
int nCount = input.readInt(); 0M)\([W9&  
nStartPos = new long[nCount]; Pa#Jwo  
nEndPos = new long[nCount]; /|#2ehE  
for(int i=0;i<nStartPos.length;i++) ?"T!<L  
{ TaaCl#g$?  
nStartPos = input.readLong(); 3sIdwY)ZS_  
nEndPos = input.readLong(); '4D7:  
} Mn3j6a  
input.close(); Bn%?{z)  
} *_mER`  
catch(IOException e){e.printStackTrace ();} /;:4$2R(;  
catch(Exception e){e.printStackTrace ();} J_j4Zb% K  
} vO53?vN[m9  
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private void processErrorCode(int nErrorCode) Wb#<ctM>  
{ L>&{<M_  
System.err.println("Error Code : " + nErrorCode); pAqPHD=  
} 8kr$w$=q  
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//停止文件下载 VKw.g@BY  
public void siteStop() XR p60i6f  
{ ,\1Rf
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bStop = true; N)a5~<fBG  
for(int i=0;i<nStartPos.length;i++) osmCwM4O  
fileSplitterFetch.splitterStop(); '66nqJb*  
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} @[`]w
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} XbeT x  
//负责部分文件的抓取 k]P'D .  
**FileSplitterFetch.java #c"05/=A  
*/ YHke^Ind
 
package NetFox; (CtRU  
*b!.9pK  
6 {F#_.  
import java.io.*; F&^&"(H}  
import java.net.*; 3RI6+Cgmn  
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public class FileSplitterFetch extends Thread { a+CJJ3T-  
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String sURL; //File URL d_f*'M2Gv  
long nStartPos; //File Snippet Start Position (&V)D?/hS  
long nEndPos; //File Snippet End Position |Q@(<'8=  
int nThreadID; //Thread's ID ftRdK>a D  
boolean bDownOver = false; //Downing is over =Lb(N61  
boolean bStop = false; //Stop identical BeD>y@ it  
FileAccessI fileAccessI = null; //File Access interface L_+Fin  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cG3tn&AXi  
{ Lpnw(r9Y  
this.sURL = sURL; }5z!FXB  
this.nStartPos = nStart; "4T36b  
this.nEndPos = nEnd; s<:);-tL  
nThreadID = id; 33a}M;vx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a@9W'/?igk  
} |mdf 
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public void run() J-azBi  
{ mi5bk>o  
while(nStartPos < nEndPos && !bStop) /xr75|-8  
{ EG_P^<z  
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try{ ZEpu5`  
URL url = new URL(sURL); 9"/=D9o9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HCYy9  
httpConnection.setRequestProperty("User-Agent","NetFox"); bP|-GCKM8  
String sProperty = "bytes="+nStartPos+"-"; Q&@<?K9  
httpConnection.setRequestProperty("RANGE",sProperty); Y{@foIZ  
Utility.log(sProperty); pe).  
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InputStream input = httpConnection.getInputStream(); f'7/
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//logResponseHead(httpConnection); /Tw $}8  
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byte[] b = new byte[1024]; V' i@N  
int nRead; <h<_''+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !+YSc&R_fW  
{ vDR> Q&/K  
nStartPos += fileAccessI.write(b,0,nRead); p]toDy-}  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |TJu|zv^  
} jxq89x  
P8w56  
}XRfHQk  
Utility.log("Thread " + nThreadID + " is over!"); YluvWHWi  
bDownOver = true; ]D^; Ca  
//nPos = fileAccessI.write (b,0,nRead);
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} @00&J~D  
catch(Exception e){e.printStackTrace ();} V4
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} V.yDZ"  
} Y8fel2;  
- s{&_]A~  
|y
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//打印回应的头信息 hsQ*ozv[)  
public void logResponseHead(HttpURLConnection con) l~@ -oE  
{ A9Pq}3U  
for(int i=1;;i++) K!-iDaVI  
{ k^s7s{  
String header=con.getHeaderFieldKey(i); &##JZ  
if(header!=null) bQu@.'O!k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0f5)]  
Utility.log(header+" : "+con.getHeaderField(header)); em ]0^otM  
else 6}\J-A/  
break; /$FpceB!W  
} "Gq%^^*
 
} :&RpB^]  
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public void splitterStop() 92*"3)
  
{ "9y0]~  
bStop = true; uL~.#Y_jQ  
} SuBUhzR  
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} xp\6,Jyh  
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!\\1#:*_W  
/* 3Z%jx#  
**FileAccess.java WxtB:7J  
*//文件访问(定位，写) K#yCZ2  
package NetFox; WtMDHfwqu\  
import java.io.*; d#I; e  
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public class FileAccessI implements Serializable{ NnY+=#j7L  
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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 T{F 'Y%  
RandomAccessFile oSavedFile; T@r%~z  
long nPos; 5j5}c`:  
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public FileAccessI() throws IOException XIp>PcU^  
{ h]o{> |d9  
this("",0); ^VjF W  
} sz4;hSTy  
[>:9
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public FileAccessI(String sName,long nPos) throws IOException In#m~nE[M  
{ [*Vo`WgbD  
oSavedFile = new RandomAccessFile(sName,"rw"); ~eekv5  
this.nPos = nPos; % +M,FgW  
oSavedFile.seek(nPos); d{]2Q9g  
} ?T'a{~]R  
ey U*20  
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public synchronized int write(byte[] b,int nStart,int nLen) lfLLk?g3k  
{ v-B&"XGy:  
int n = -1; 1?".R]<{2T  
try{ 1X#gHstD  
oSavedFile.write(b,nStart,nLen); N[xa=  
n = nLen; NHaqT@:  
} 2>kk6=<5'  
catch(IOException e) T2XLP  
{ .;;
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e.printStackTrace (); s{0c.
M  
} XILreATK@  
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return n; _%PEv{H0.  
} 7qhX`$  
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[4\n(/  
} GbBz;ZV%z,  
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/* a,?u 2  
**SiteInfoBean.java JZoH -  
*/ XchVsA  
package NetFox; 'oZdMl&  
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public class SiteInfoBean { @kB^~Wf
 
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private String sSiteURL; //Site's URL l9F]Lw  
private String sFilePath; //Saved File's Path `"eIzLc%o6  
private String sFileName; //Saved File's Name `it  
private int nSplitter; //Count of Splited Downloading File [xl+/F7  
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public SiteInfoBean() 3TNj*jo  
{//nSplitter的缺省值为5 #Dl=K<I  
//default value of nSplitter is 5 '/<f'R^  
this("","","",5); Hni?r!8r  
} _'U(q\ri  
|j!U/n.%w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x^6b$>1  
{ Q=F4ZrNqD  
sSiteURL= sURL; 70T{tB  
sFilePath = sPath; Q>l5:2lq  
sFileName = sName; G"F:68  
this.nSplitter = nSpiltter; N/r8joi#  
}x?2txuu  
U oG+du[  
} $5J~4B"%3  
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[Qn$i/`J  
public String getSSiteURL() c7t.  
{ &>
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return sSiteURL; Og9:MFI  
} vptBDfzz  
&K-0ld(;  
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public void setSSiteURL(String value) \@GKVssw  
{ sx@%3j  
sSiteURL = value; FYX"q-Z  
} c"`CvQO64  
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public String getSFilePath() 9wpV} .(  
{ U$wD'v3pw  
return sFilePath; t}f,j^`e  
} ~cb7]^#u1l  
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public void setSFilePath(String value) ,2`F
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{ Q
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sFilePath = value; 05Y4=7,!  
} &4jc3_UKV  
!ZzDSQ;  
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public String getSFileName() uN9J?j*ir  
{ TX$4x~:  
return sFileName; :a'[4w  
} 9<-7AN}Z  
L3'$"L.|u  
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public void setSFileName(String value) 3 cF4xUIZ  
{ 6~!l7HqO  
sFileName = value; +$\/HO  
} m"RSDM!  
!6l}s$1i|  
rtZEK:.#  
public int getNSplitter() ja+PVf  
{ ]r(s02  
return nSplitter; aW;DfH  
} N2$uw@s  
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public void setNSplitter(int nCount) Q;y)6+VU4  
{ <@J0 770  
nSplitter = nCount; HCZVvsG  
} G)3Q|Vc  
} P|QM0GI  
-5d^n\CDK  
J @^Ypq  
/* #B!<gA$/  
**Utility.java tlpTq\;  
*/ JbXd9AMh2  
package NetFox; *8I &|)x  
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public class Utility { Qk]^]I  
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public Utility() o&:'MwU  
{ Fu[<zA^  
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} dd:vQOF;  
ZXC_kmBN/  
//线程睡眠 k8E{pc6;  
public static void sleep(int nSecond) D2 X~tl5<  
{ ^~JF7u  
try{ S$NJmXhx5  
Thread.sleep(nSecond); {YF(6wVl  
} J*;= f8  
catch(Exception e) OZ6:u^OS]  
{ xt1Ug~5  
e.printStackTrace (); .njk^,N  
} ~UQXt r  
} LW!>_~g-  
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//日志 i>%A0.9  
public static void log(String sMsg) (DY&{vudF  
{ ]\(Ho   
System.err.println(sMsg); \IO
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} XWag+K  
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public static void log(int sMsg) yyM`J7]J  
{ DLD5>  
System.err.println(sMsg); PpezWo)9  
} !Wz4BBU8o  
} ^5rB/y,  
_t?#
 
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/* "X \Yp_g  
**TestMethod.java UT_kw}1o  
*/ ,ut7`_Fy  
package NetFox; kc/"  
\HQw$E/p  
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public class TestMethod { YT'olk  
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public TestMethod() ?.^n,[2  
{ ///xx/weblogic60b2_win.exe i'p6#  
try{ z>z9xG'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :pvB}RYD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =d#(n M*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [,sm]/Xlc  
fileFetch.start(); jr/IU=u*v  
} ag6[Nk  
catch(Exception e){e.printStackTrace ();} H @5dj}  
vOo-
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} Q%x-BZb~  
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public static void main(String[] args) \hI|I!sDWy  
{ 6G7+&g`  
new TestMethod(); ng:B;; m  
} yb!/DaCd  
} =HjC.h  
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