http断点续传简单实现（java)

/* #~54t0|Cd>  
**SiteFileFetch.java &_ Ewu@4  
*/ A\Q]o#U  
package NetFox;  yf!  
import java.io.*; AA9OElCa  
import java.net.*; &E$jAqc  
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*Wv]DV=\  
public class SiteFileFetch extends Thread { ,ijgqEN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e =V
u;  
long[] nStartPos; //开始位置 Re('7m h~  
long[] nEndPos; //结束位置 *TA${$K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $!Z6?+  
long nFileLength; //文件长度 ZGa>^k[:  
boolean bFirst = true; //是否第一次取文件 ;uNcrv0J  
boolean bStop = false; //停止标志 )'xTDi  
File tmpFile; //文件下载的临时信息 PIn'tV  
DataOutputStream output; //输出到文件的输出流 d:O>--$_tw  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） V^=z\wBZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException X3I
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{ I@a7AuOw  
siteInfoBean = bean; 'Zf_/y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;Aiuy{<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &}VGC=F;d  
if(tmpFile.exists ()) ePK^v_vBD  
{ w`,[w,t  
bFirst = false; uh%%MhTjv  
read_nPos(); (1fE^KF@f  
} #Oz<<G<  
else 49~5U+x;  
{ m;lwMrY\7>  
nStartPos = new long[bean.getNSplitter()]; vL{~?vq6  
nEndPos = new long[bean.getNSplitter()]; D|,d_W  
} =;0#F&  
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nt  
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} Y.3]vno?X  
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public void run() }]N7CWy  
{ u}D.yI8  
//获得文件长度 xIf,1g@Cq9  
//分割文件 K5z*DYT  
//实例FileSplitterFetch ~K
8eRT  
//启动FileSplitterFetch线程 [#kfl  
//等待子线程返回 Lg[*P8wE  
try{ hAHl+q)w?  
if(bFirst) CtV$lXxup  
{ uz".!K[,wE  
nFileLength = getFileSize(); 7m{
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if(nFileLength == -1) 4\x'$G  
{ THWT\3~,  
System.err.println("File Length is not known!"); R8F[ 7&(  
} *TVr| to  
else if(nFileLength == -2) r5Jy( ~  
{ ^E8&!s  
System.err.println("File is not access!"); PQ<""_S||  
} 9XX&~GW/  
else F(^vD_
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{ wo$9$~(  
for(int i=0;i<nStartPos.length;i++) VZ'[\3J  
{ ] NL-)8u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9xyj,;P>  
} _N$3c<dY'  
for(int i=0;i<nEndPos.length-1;i++) RlyF#X#7{  
{ >B U0B  
nEndPos = nStartPos[i+1]; ++-HdSHY  
} 2aX|E4F  
nEndPos[nEndPos.length-1] = nFileLength; xmb]L:4F  
} h^D?G2O  
} SGre[+m~m  
B/:q  
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//启动子线程 n@XI$>B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QxH%4 )?  
for(int i=0;i<nStartPos.length;i++) cKdn3 2Y4  
{ tq H7M0Ry  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tisSj?+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?>cx;"xF  
nStartPos,nEndPos,i); >N62t9Ll[  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g&!UaJ[#9  
fileSplitterFetch.start(); s]50Y-C  
} {mrTpw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D+P(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C$(US8:{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Yrs7F.Y"  
nEndPos = " + nFileLength); #(F/P!qk  
// fileSplitterFetch[nPos.length-1].start(); <{GpAf8-  
L15?\|':
Y  
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//等待子线程结束 f6vhW66:?x  
//int count = 0; &a5UQ>  
//是否结束while循环 8=CdO|XV
 
boolean breakWhile = false; "s]r"(MX  
<K;  
~~a,Fyko2  
while(!bStop) qq.M]?Z  
{ _8A  
write_nPos(); h/5|3  
Utility.sleep(500); #%N v\g;  
breakWhile = true; G d~ v _  
S"'0lS   
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for(int i=0;i<nStartPos.length;i++) s!,m,l[P  
{ {,NGxqhE  
if(!fileSplitterFetch.bDownOver) "5 ;fuM1  
{ uzg(C#sp  
breakWhile = false; Su?e\7aj  
break; U{i xok  
} ${m;x:'  
} lC/1,Z/M  
if(breakWhile) EQI9J#;+  
break; @W}cM  
v+Eub;m   
[As9&]Bv5  
//count++; %"-bG'Yc  
//if(count>4) g>G+?PY  
// siteStop(); !yqez  
} & "i4og<  
9gq+,g>E_  
R !g'zS'  
System.err.println("文件下载结束！"); q9Zp8&<EqH  
}  _
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catch(Exception e){e.printStackTrace ();} ~,ZU+  
} {uUV(FzF6  
aeZ$Wu>]W  
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//获得文件长度 1lo.X_  
public long getFileSize() &~mJ ).*  
{ ^h\(j*/#X  
int nFileLength = -1; I3gl+)Q  
try{ {p\ll  
URL url = new URL(siteInfoBean.getSSiteURL()); )<Fq}Q86  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n%|og^\0  
httpConnection.setRequestProperty("User-Agent","NetFox"); '0-YFx'U0V  
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>|X )  
int responseCode=httpConnection.getResponseCode(); 
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if(responseCode>=400) Su/8P[q_  
{ Sq&r ;  
processErrorCode(responseCode); "QD>m7  
return -2; //-2 represent access is error E1r-$gf_  
} _(zZrUHB  
'C4cS[1  
M*!WXQlud  
String sHeader; :V3z`}Rl  
(Bq^ D9  
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for(int i=1;;i++) Y5CDdn  
{ HQvJ*U4++  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2&"qNpPtE  
//Utility.log(in.readLine()); .k:heN2-x  
sHeader=httpConnection.getHeaderFieldKey(i); M>E~eb/  
if(sHeader!=null) +GJPj(S  
{ u,V_j|(e  
if(sHeader.equals("Content-Length")) mC0_rN^Aj  
{ b)@D@K"5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @9eN\b%I^H  
break; Sn S$5o  
} It7R}0Smg  
} ,Nt^$2DZW  
else c/F
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break; iC3C~?,
7  
} nY7gST  
} )=#e*1!b  
catch(IOException e){e.printStackTrace ();} +OqEe[Wk#  
catch(Exception e){e.printStackTrace ();} l\F71pwSI  
? cXW\A(  
55'  
Utility.log(nFileLength);
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return nFileLength; Nc&J%a  
} ~`Rar2%B  
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//保存下载信息（文件指针位置） |.,]0CRg  
private void write_nPos() 41R6V>e@9J  
{ LPBa!fq  
try{ m~ 5"q%;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &8w# 4*W  
output.writeInt(nStartPos.length); O2\(:tvw  
for(int i=0;i<nStartPos.length;i++) 67hfve  
{ 5RvE ),  
// output.writeLong(nPos); :_y!p  
output.writeLong(fileSplitterFetch.nStartPos); ywl=@  
output.writeLong(fileSplitterFetch.nEndPos); {1Y
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} DI8<0.L  
output.close(); gyD;kn\CP  
} 5@%.wb4  
catch(IOException e){e.printStackTrace ();} (:qc[,m  
catch(Exception e){e.printStackTrace ();} /2zan}  
} gs;^SRE I  
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//读取保存的下载信息（文件指针位置） &oMWs]0  
private void read_nPos() M,S'4Szuk  
{ 9sT5l"?g  
try{ /zt M'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hO&b\#@
~  
int nCount = input.readInt(); y/y~<-|<@  
nStartPos = new long[nCount]; PBnH#zm  
nEndPos = new long[nCount]; 71\53Qr#U  
for(int i=0;i<nStartPos.length;i++) #H w(w  
{ 'St6a*  
nStartPos = input.readLong(); &:g:7l]g  
nEndPos = input.readLong(); *s*Y uY%y  
} ?9a%g\`?:  
input.close(); A $gn{ c  
} n'v\2(&uYN  
catch(IOException e){e.printStackTrace ();} +x=)Kp>  
catch(Exception e){e.printStackTrace ();} ] re=8s6  
} R__:~uv,  
#M16qOEw  
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private void processErrorCode(int nErrorCode) Z;Hkx1  
{ L)bMO8JH~m  
System.err.println("Error Code : " + nErrorCode); <mE`<-$  
} VFL^-tXnA^  
qU7_%Z  
'ZW(Hjrd  
//停止文件下载 C)z4Cn9#  
public void siteStop() )&c#?wx'w  
{ k?14'X*7yu  
bStop = true; m4 (pMrJ  
for(int i=0;i<nStartPos.length;i++) \~l_w ,Poo  
fileSplitterFetch.splitterStop(); 3

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 /ooGyF  
} &2y4k"B&)  
} ]8\I{LR  
//负责部分文件的抓取 P>C'?'Q7  
**FileSplitterFetch.java ki9&AFs2X  
*/ YpDJ(61+  
package NetFox; "Gp[.=.z?  
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import java.io.*; Reikf}9Q  
import java.net.*; HeAXZA,  
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public class FileSplitterFetch extends Thread { HrBJi  
U=.PL\  
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String sURL; //File URL 0N,<v7PX  
long nStartPos; //File Snippet Start Position ,x8;| o5  
long nEndPos; //File Snippet End Position b# N"}-\^  
int nThreadID; //Thread's ID @'R)$:I%L  
boolean bDownOver = false; //Downing is over 35& ^spb  
boolean bStop = false; //Stop identical 8%7%[WC#  
FileAccessI fileAccessI = null; //File Access interface pbzFzLal  
VI2lwE3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8)X9abC  
{ 7Jf~Bn  
this.sURL = sURL; 6{y7e L3!  
this.nStartPos = nStart; 9(N  
this.nEndPos = nEnd; fjRVYOG#  
nThreadID = id; @V%\Gspv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 VL9wRu;  
} +`HMl;0m  
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public void run() +~^S'6yB  
{ TEC^|U`G  
while(nStartPos < nEndPos && !bStop) SyvoN,;Q  
{ +/ukS6>gr  
,X?/FAcb
 
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try{ b(*\4n  
URL url = new URL(sURL); !#KKJ`uB"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b#6S8C+@  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~:a1ELqVw  
String sProperty = "bytes="+nStartPos+"-"; !mNst$-H4  
httpConnection.setRequestProperty("RANGE",sProperty); | &X<-  
Utility.log(sProperty); tIuM9D{P  
9M96$i`P  
*()['c#CC  
InputStream input = httpConnection.getInputStream(); fkxkf^g)  
//logResponseHead(httpConnection); *g(d}C!  
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byte[] b = new byte[1024]; H/D=$)3op  
int nRead; #1<m\z7l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kKyU?/aj  
{ 5|H;%T3_  
nStartPos += fileAccessI.write(b,0,nRead); 8M5)fDu*?  
//if(nThreadID == 1) \"
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d0aXA+S%  
} LqWiw24#  
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Utility.log("Thread " + nThreadID + " is over!"); 6Og@tho  
bDownOver = true; 7'\.QJ!<  
//nPos = fileAccessI.write (b,0,nRead); Z0<Vss  
} s%jBIeh  
catch(Exception e){e.printStackTrace ();} ~fXNj-'RW  
} #HcQ*BiF3  
} K"!rj.Da  
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//打印回应的头信息 Id=
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public void logResponseHead(HttpURLConnection con) IL@yGuO,  
{ gfL:SP8  
for(int i=1;;i++) 7U [C=NL  
{ 4&*lpl*N  
String header=con.getHeaderFieldKey(i); =D(a~8&,  
if(header!=null) Q
7+WV`&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LK h=jB^bT  
Utility.log(header+" : "+con.getHeaderField(header)); 48xgl1R(j  
else Ab$E@H#  
break; eXl
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} QytO0K5  
} :DH@zR  
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public void splitterStop() f}c;s  
{ 8r(Vz  
bStop = true; ?wtKi#k'v#  
} YdI6|o@vc  
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} ,88B@a  
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/* lr&2,p<  
**FileAccess.java {tVA(&\<  
*//文件访问(定位，写) 2?,lr2  
package NetFox; <(E)M@2  
import java.io.*; T)tr"<F5NP  
S%RxYJ(  

ZPf&4#|  
public class FileAccessI implements Serializable{ rT="ciQ  
thPAD+u.3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jHq+/\  
RandomAccessFile oSavedFile; -dMH>e0  
long nPos; P#pb48^-  
55v=Ij?M  
:/->m6C`0  
public FileAccessI() throws IOException <_/etw86Z  
{ T:j41`g%s  
this("",0); 9Zx| L/\  
} ^3HSw ?a"  
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mcwd
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public FileAccessI(String sName,long nPos) throws IOException #cR5k@  
{ ""`z3-  
oSavedFile = new RandomAccessFile(sName,"rw"); ycN!N  
this.nPos = nPos; SP0ueAa}  
oSavedFile.seek(nPos); z%fjG}z  
} m<Gd 6V5  
319 4]  
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public synchronized int write(byte[] b,int nStart,int nLen) kb-XEJ}L  
{ H( LK}[  
int n = -1; )m-(-I  
try{ b#709VHm  
oSavedFile.write(b,nStart,nLen); B4OFhtYE  
n = nLen; 
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} 0>Kgz!I  
catch(IOException e) Y}vV.q  
{ :hHKm|1FE  
e.printStackTrace (); V\Lh(zPt  
} |}l/6WHB  
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return n; rp]H&5.*  
}
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} #;2kN &  
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/* d.snD)X  
**SiteInfoBean.java H8c -/  
*/ ^]LWcJ?"^!  
package NetFox; 2$Z4 >!  
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public class SiteInfoBean { voN,u>U  
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t-FrF</0  
private String sSiteURL; //Site's URL K>+c2;
t;  
private String sFilePath; //Saved File's Path <XpG5vV  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File bmC{d  
5X`m.lhUc  
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public SiteInfoBean() Nrp1`qY  
{//nSplitter的缺省值为5 i/DUB<>p6  
//default value of nSplitter is 5 0Q/BTT%X  
this("","","",5); +_fxV|}P  
} xirZ.wjW  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5,V3_p:)VI  
{ DTV"~>@  
sSiteURL= sURL; bq}o#d5p-_  
sFilePath = sPath; SR'u*u!  
sFileName = sName; XuW>GT/  
this.nSplitter = nSpiltter; 4q^'MZm1  
z!\)sL/"  
8z"*CJ@  
} "M:0lUy  
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public String getSSiteURL() y[:xGf]8@  
{ Bt-2S,c
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return sSiteURL; (ft$ R?  
} &Ukh  
h.h\)>DM@  
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public void setSSiteURL(String value) @ **]o  
{ %:]ive]e  
sSiteURL = value; ;l=ZW  
} kC-OZVoO  
{`1gDKH  
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public String getSFilePath() iyf vcKO  
{ t5WW3$Nf  
return sFilePath; a{7'qmN1  
} p!3!&{  
vTU*6
)  
%Y//}  
public void setSFilePath(String value) a@V`EEZ  
{ J PK
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sFilePath = value; g O ;oM?|  
} <mdHca  
a
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f& >[$zh  
public String getSFileName() /V@9!  
{ =Hwlo!  
return sFileName; s xp>9&  
} tjTnFP/=  
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public void setSFileName(String value) m3i+b  
{ TY6Q;BTU  
sFileName = value; Ga
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} NhYce>  
yvp$s  
dGY:?mf&  
public int getNSplitter() rsgTd\b  
{ /f0*NNSat-  
return nSplitter; 2/m4|  
} sbi+o,%1  
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~ '/Yp8(  
public void setNSplitter(int nCount) *kE<7  
{ yhSbX4Q  
nSplitter = nCount; q71~Y:7f  
} qzt.k^'-^  
} wYAi-gdOi  
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+#V.6i  
/* $zUHka  
**Utility.java &K.js  
*/ %!r@l7<  
package NetFox; g`9`/  
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public class Utility { f5ttQ&@FF  
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public Utility() |.EC>D/  
{ 3JJE
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} xg8$ <Ut  
a 0+W-#G  
//线程睡眠 `+0K~k|DC  
public static void sleep(int nSecond) 2{;~Bgd  
{ O.Xhi+  
try{ |Jpi|'  
Thread.sleep(nSecond); .Gq]Mrim9G  
} ;\48Q;  
catch(Exception e) Lsb`,:  
{ p38RgEf  
e.printStackTrace (); AREpZ2GiU  
} '74*-yd  
} * ,#SwZ  
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//日志 m:x<maP#E  
public static void log(String sMsg) z=1N}l~|*  
{ # ;3v4P  
System.err.println(sMsg); &X&
msEM  
} T6M=BkcP  
m[8?d~  
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public static void log(int sMsg) 8ZL9>"%l  
{ `),ACkU>U  
System.err.println(sMsg); ,LftQ1*;  
} Of.%rpgy  
} gEISnMH  
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]g
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/* y)uxj-G  
**TestMethod.java ZZ2vdy38  
*/ hywy(b3  
package NetFox; 4D=^24f`0  
hZwJ@ Vm#  
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public class TestMethod { B x-"<^<  
&3CC |  
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public TestMethod() %Fp1c K  
{ ///xx/weblogic60b2_win.exe JxmFUheLt  
try{ #M@Ki1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J-
5E# v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [oDu3Qn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &e)V!o@wJV  
fileFetch.start(); u{8:VX  
} Aq;WQyZ2  
catch(Exception e){e.printStackTrace ();} u#)ARCx,w  
{n 4W3  
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} OOZxs?pR  
8>AS
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public static void main(String[] args) 0HPqoen$  
{ *IQQsfL)  
new TestMethod(); .1YiNmW=  
} nA#N,^Rr  
} `G "&IQ8.  
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