http断点续传简单实现（java)

/* 4c0 =\v  
**SiteFileFetch.java clyZD`*  
*/ $MhfGMk!'  
package NetFox; O4t0 VL$  
import java.io.*; K+|G9  
import java.net.*; lsq\CavbM  
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public class SiteFileFetch extends Thread { Qa>t$`o`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean POB6#x  
long[] nStartPos; //开始位置 bS7%%8C  
long[] nEndPos; //结束位置 @?e+;Sx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QN)EPS:y  
long nFileLength; //文件长度 Q!.JV.(  
boolean bFirst = true; //是否第一次取文件 xU9T8Lw  
boolean bStop = false; //停止标志 5d|h
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File tmpFile; //文件下载的临时信息 <aSjK#  
DataOutputStream output; //输出到文件的输出流 1K\zamBg  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） As"% u  
public SiteFileFetch(SiteInfoBean bean) throws IOException VYG o;  
{ 4fSGc8  
siteInfoBean = bean; o@2Y98~Q}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \8Y62  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &uP,w#  
if(tmpFile.exists ()) eU(cn8/}  
{ 7G':h0i8  
bFirst = false; %/.yGAPkx  
read_nPos();  |pgrR7G'  
} vX30Ijm  
else tqk^)c4FF(  
{ *E.uqu>I  
nStartPos = new long[bean.getNSplitter()]; tw k  
nEndPos = new long[bean.getNSplitter()]; b=+3/-d  
} T$!Pkdh  
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} dj-/%MU  
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public void run() tXfXuHa  
{ JIatRc?g  
//获得文件长度 !(A<  
//分割文件 gkhmQd  
//实例FileSplitterFetch FeL!%z  
//启动FileSplitterFetch线程 ?uh%WN6nU]  
//等待子线程返回 `}.jH1Fx/m  
try{ adY ,Nz  
if(bFirst) R+r;V]-/
 
{ {&TP&_|H  
nFileLength = getFileSize(); bUU\bc  
if(nFileLength == -1) br;~}GR_h
 
{ }y>/#]X  
System.err.println("File Length is not known!"); yU|=)p5  
} y3@m1>]09  
else if(nFileLength == -2) O%s7}bR3  
{ z?<Xx?Kk  
System.err.println("File is not access!"); a! gj_  
} >c)-o}bd^  
else ^UmhSxQ##  
{ Qa#Em1co  
for(int i=0;i<nStartPos.length;i++) ^Ycn&
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{ v`&>m'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]kdU]}z  
} +OaBA>Jh9  
for(int i=0;i<nEndPos.length-1;i++) ak_n  
{ *JArR1J  
nEndPos = nStartPos[i+1]; 1EMrXnv,  
} cC pNF `DN  
nEndPos[nEndPos.length-1] = nFileLength; h^v+d*R N  
} E3V_qT8  
} ^6@6BYf)  

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m^$KDrkD  
//启动子线程 K |^OnM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p'4ZcCW?f  
for(int i=0;i<nStartPos.length;i++) |-9##0H  
{ 9}T(m(WQVu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *RD<*l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~--b#o{  
nStartPos,nEndPos,i); 6 m%/3>q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /"@k_[O  
fileSplitterFetch.start(); 9]gV#uF  
} #X"fm1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m$`4.>J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .R^q$U~v3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t=IM"ZgfL  
nEndPos = " + nFileLength); 0ZJrK\K;  
// fileSplitterFetch[nPos.length-1].start(); th|'t}bWV  
&[t} /+)  
)1/J5DI @8  
//等待子线程结束 _};T:GOT  
//int count = 0; jwp?eL!7  
//是否结束while循环 Bq~?!~\?.  
boolean breakWhile = false; CqLAtS X7  
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while(!bStop) =>*9"k%m  
{ LG vPy  
write_nPos(); *5mJA -[B+  
Utility.sleep(500); T5eJIc3a"  
breakWhile = true; H,(4a2zx  
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for(int i=0;i<nStartPos.length;i++) U]Fnf?(  
{ Va$JfWef  
if(!fileSplitterFetch.bDownOver) <z QUa  
{ "y-/ 9C  
breakWhile = false; ]RuH6d2d|  
break; NchEay;`  
} PEMuIYm$  
} T,uJO<  
if(breakWhile) ]t-B-(D  
break; 72\o6{BiC  
& &:ZY4`  
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//count++; /h,-J8[  
//if(count>4)
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// siteStop(); qf*e2"~v  
} (,['6k<  
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System.err.println("文件下载结束！"); /t04}+,e^  
} YR.f`-<Z  
catch(Exception e){e.printStackTrace ();} Mb+CtI_'  
} uDMyO<\  
SJO^.[  
pAH9  
//获得文件长度 @rlL'|&X*  
public long getFileSize() \GCT3$  
{ i%otvDn1  
int nFileLength = -1; J%P{/nR  
try{ |#5_VEG  
URL url = new URL(siteInfoBean.getSSiteURL()); ?mh0^G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M5{vYk>,1Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); SXRND;-W8  
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71G00@&w9D  
int responseCode=httpConnection.getResponseCode(); +~?K@n  
if(responseCode>=400) 0E`6g6xMS  
{ GD<pqm`vVY  
processErrorCode(responseCode); *h~(LH"tN  
return -2; //-2 represent access is error yHxi^D]  
} @l?2",  
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String sHeader; Cgn@@P5ZC  
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for(int i=1;;i++) QW>(LGG=  
{ C44*qiG.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^ =RSoR  
//Utility.log(in.readLine()); O;RNmiVoq  
sHeader=httpConnection.getHeaderFieldKey(i); '?b.t2  
if(sHeader!=null) 8zH/a   
{ g&L $5  
if(sHeader.equals("Content-Length")) }\d3   
{ $F~hL?"?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UY&DX
IPM  
break; (=w ff5U  
} 0@2pw2{Ru  
} hJ0m;j&4y  
else Yd$64d7,h  
break; N0
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} nXxSv
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} 5h>t4 [~  
catch(IOException e){e.printStackTrace ();} /[Sy;wn  
catch(Exception e){e.printStackTrace ();} vQ
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!' jXN82  
Utility.log(nFileLength); ybVdWOqv  
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return nFileLength; {#%;HqP  
} }$1Aw%p^  
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[  
//保存下载信息（文件指针位置） }NETiJ"6  
private void write_nPos() 8A|i$#.&  
{ 2s8(r8AI  
try{ 0%5x&vx'S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z,/y2H2  
output.writeInt(nStartPos.length); M^~  
for(int i=0;i<nStartPos.length;i++) gb@ |\n  
{ My\  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); >jBnNA@  
output.writeLong(fileSplitterFetch.nEndPos); o!M*cyq  
} AZ
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output.close(); ^p!bteA>  
} s*W)BK|+?  
catch(IOException e){e.printStackTrace ();} w\3'wD!  
catch(Exception e){e.printStackTrace ();} 7`6JK  
} Id'@!U:NA  
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//读取保存的下载信息（文件指针位置） [8C6%n{W  
private void read_nPos()
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{ k0R;1lZ0n  
try{ |A@Gch fd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =v]
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int nCount = input.readInt(); 3a#
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nStartPos = new long[nCount]; 9@|X~z5E  
nEndPos = new long[nCount]; b3!,r\9V  
for(int i=0;i<nStartPos.length;i++) 9 ulr6  
{ fO{E65uA  
nStartPos = input.readLong(); _G5MQ%z  
nEndPos = input.readLong(); yy-\$<j  
} +qEvz<kch  
input.close(); aXefi'!6  
} QZ54Osdl  
catch(IOException e){e.printStackTrace ();} "RJf2~(ZX  
catch(Exception e){e.printStackTrace ();} ))>)qav  
} xj!_]XJ^w  

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private void processErrorCode(int nErrorCode) c~UYs\  
{ _;+N=/l0  
System.err.println("Error Code : " + nErrorCode); $0K%H  
} 0IEFCDeCO  
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<U$A_]*w  
//停止文件下载 #Rdq^TGMi;  
public void siteStop() weiqt *,8  
{ _"`U.!3*  
bStop = true; __V6TDehJ$  
for(int i=0;i<nStartPos.length;i++) x 1
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fileSplitterFetch.splitterStop(); =pS\gLQu  
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} *
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} &p$SFH?s  
//负责部分文件的抓取 t9()?6H\  
**FileSplitterFetch.java B$
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*/ -zVa[&  
package NetFox; -ijQTB  
X+K$y:UZ  
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import java.io.*; b_ |  
import java.net.*; /-39od0  
8EPV\M1%  
ft[g1  
public class FileSplitterFetch extends Thread { %?EOD=e=  
*<
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e+F5FAMR68  
String sURL; //File URL #={L!"3?e  
long nStartPos; //File Snippet Start Position SS;QPWRZ  
long nEndPos; //File Snippet End Position FBcF  
int nThreadID; //Thread's ID yX(6C]D  
boolean bDownOver = false; //Downing is over n]@+<TA<uA  
boolean bStop = false; //Stop identical <nj[=C4v  
FileAccessI fileAccessI = null; //File Access interface v=|BqG`  
k852M^JP  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QWf)5S  
{ Rh%/xG#k  
this.sURL = sURL; aM9St!i  
this.nStartPos = nStart; _|Ml6;1aZ  
this.nEndPos = nEnd; `B6{y9J6  
nThreadID = id; rQ'tab.,]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G1~|$X@@  
} k[
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public void run() D.<CkDB  
{ &hba{!`y  
while(nStartPos < nEndPos && !bStop) 
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{ 5e,Dk0d  
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try{ .VmI4V?}h  
URL url = new URL(sURL); ZjEO$ts=@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Md {,@ G  
httpConnection.setRequestProperty("User-Agent","NetFox"); G6eC.vU]j  
String sProperty = "bytes="+nStartPos+"-"; xM;gF2  
httpConnection.setRequestProperty("RANGE",sProperty); jl2nRo  
Utility.log(sProperty); )
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InputStream input = httpConnection.getInputStream(); g#_?Vxt  
//logResponseHead(httpConnection); u6y\GsM.a  
5!Z+2Cu]  
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byte[] b = new byte[1024]; ?/)5U}*M0T  
int nRead; =O)JPo&iwY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MZw%s(lv  
{ G"TPu_g  
nStartPos += fileAccessI.write(b,0,nRead); 6DJ,/J2F  
//if(nThreadID == 1) :<&}/r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DcbL$9UI  
} <'~8mV1  
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Mn~A;=%qF  
Utility.log("Thread " + nThreadID + " is over!"); !n
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bDownOver = true; 0v0Y( Mo@  
//nPos = fileAccessI.write (b,0,nRead); vEzzdDwi6  
} 2c%}p0<;|?  
catch(Exception e){e.printStackTrace ();} ,0
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} :/%Vpdd@  
} ^MJGY,r6b  
h;4g#|,  
|7`Vw Z  
//打印回应的头信息 4&ea*w  
public void logResponseHead(HttpURLConnection con) k #*|-?  
{ &OhKx  
for(int i=1;;i++) o@LjSQ5!  
{ qqzQKN  
String header=con.getHeaderFieldKey(i); t48(GKF  
if(header!=null) {C]M]b*F6(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); iW"L!t#\|  
Utility.log(header+" : "+con.getHeaderField(header)); 1wc -v@E  
else +zs6$OI]V  
break; FYcMvY  
} ZVp\5V*  
} &{]%=stI  
@su{Uno8/  
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public void splitterStop() Xb^\{s?b  
{ >>$IHz4Z"  
bStop = true; RaU.yCYyu  
} dWqFP  
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} Yn<0D|S;X  
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/* o~-X7)]  
**FileAccess.java Q5,@P?  
*//文件访问(定位，写) 4G>|It  
package NetFox; =(n'#mV  
import java.io.*; 3K?0PRg  
mzT} C&hfP  
9uS7G*  
public class FileAccessI implements Serializable{ K%pmE?%,8  
#dpt=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <,E*,&0W  
RandomAccessFile oSavedFile; /2@%:b)  
long nPos; 0X0D8H(7Q  
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public FileAccessI() throws IOException 3-mw-;.  
{ +1)C&:  
this("",0); `C*!de]Y%  
} <Y orQ>  
44W3U~1  
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public FileAccessI(String sName,long nPos) throws IOException T?\CAk>  
{ Rm*}<JN31  
oSavedFile = new RandomAccessFile(sName,"rw"); y2+a2  
this.nPos = nPos; =O;SXzgE  
oSavedFile.seek(nPos); @l(Y6m|v\  
} jYy0^)6X(  
4iLU "~  
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public synchronized int write(byte[] b,int nStart,int nLen) R&4E7wrdP  
{ ]~qN<x  
int n = -1; Vd?v"2S(9  
try{ m_(hCY=Q$  
oSavedFile.write(b,nStart,nLen); q~^:S~q  
n = nLen; yX-xVvlv@  
} 13QC
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catch(IOException e) ^z^>]Qd  
{ + kF[Oh#  
e.printStackTrace (); P+b^;+\1s  
} %b{!9-n}  
^ Wl/  
c}QJ-I  
return n; aqM_t  
} Q jBCkx]g  
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} t3GK{X  
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/* <dN=d3S  
**SiteInfoBean.java iCK$ o_`?  
*/ +zD'r5  
package NetFox; x5|v# -F ^  
A$F;fCV*  
^97ZH)Ww  
public class SiteInfoBean { \Zv =?\  
.]e6TFsrO  
btF%}<o)  
private String sSiteURL; //Site's URL _Y|kX2l S@  
private String sFilePath; //Saved File's Path j?,*fp8  
private String sFileName; //Saved File's Name u W|x)g11a  
private int nSplitter; //Count of Splited Downloading File 7[H`;l  
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public SiteInfoBean() cP2R24th  
{//nSplitter的缺省值为5 &JlR70gdHi  
//default value of nSplitter is 5 d*>k ]X@G  
this("","","",5); JKT+ q*V  
} ,jnRt%W  
3kQ^f=Wd  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gkz#kiGF  
{ c_q+
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sSiteURL= sURL; 0X?fDz}jd  
sFilePath = sPath; ~yi&wbTjM  
sFileName = sName; \!QF9dP4  
this.nSplitter = nSpiltter; =Yj[MVn  
z{g<y^Im+E  
I7PWOd  
} 9AYe,R  
@c!67Z  
L%d?eHF  
public String getSSiteURL() 12PE{Mut  
{ v,+l xY  
return sSiteURL; h<K;VpL6  
} JYr7;n'!  
SU'1#$69F  
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public void setSSiteURL(String value) nh=Us^xD  
{ VQ?H:1R  
sSiteURL = value; x#0@$  
} 9(F?|bfk  
LQ@|M.$A  
02^(z6K'&?  
public String getSFilePath() qX'a&~s)n  
{ R$fIb}PDr  
return sFilePath; T+nC>}*jgJ  
} (bt]GAxb1  
'h^DI`  
$JB:rozE  
public void setSFilePath(String value) C55n  
{ Kg`x9._2  
sFilePath = value; ]0i2]=J&,  
} (1,#=e+  
IA`8ie+  
c'+r[rSn1  
public String getSFileName() ;]M67ma7C  
{ ba9<(0`  
return sFileName; 1ysLZ;K  
} gqD^Bs'VF  
JGDUCb~  
YaZt+WA  
public void setSFileName(String value)  |~uzQU7  
{ W:poUG1UR  
sFileName = value; !(_xu{(DL  
} K2rS[Kdfaq  
9H}iX0O  
~}0hN]*G  
public int getNSplitter() K^vp(2  
{ -mHhB(Td'  
return nSplitter; z{3%Hq  
} /Tf*d>Yh;  
0*;9CH=BE  
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public void setNSplitter(int nCount) q&$
0i   
{ 3d'ikkXK  
nSplitter = nCount; y [9}[NMZ  
} 06@0r  
} To8v#.i  
wt.{Fqm  
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/* lMzCDx!m  
**Utility.java N"x\YHp  
*/ 
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package NetFox; ?*R^?[  
?3TK7]1V:  
p@
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public class Utility { KO]?>>5S6  
FV6he[,  
tbzvO<~  
public Utility() q\b ?o!#_  
{ Y
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ua|Z`qUyq  
l&sO?P[ /  
} Xf_tj:eO~  
~sHZh  
//线程睡眠 &]yJCzo]  
public static void sleep(int nSecond) %M)oHX1p  
{ 9poEUjBI  
try{ wz0$g4  
Thread.sleep(nSecond); ?tC}M;~  
} g.Caapy  
catch(Exception e) h,'mN\6t  
{ V0'p1J tD  
e.printStackTrace (); .FbZVYc]  
} 8X ?GY8W:  
} KYRm Ui#  
,Z*3,/a  
//日志 @2~O^5[>  
public static void log(String sMsg) 0o=6A<#x  
{ K]pKe"M  
System.err.println(sMsg); y|+~>'^JR  
} p]
V-<
 
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&X]=Qpl  
public static void log(int sMsg) ptWG@"j/b  
{ BtpjQNN  
System.err.println(sMsg); x:n9dm  
}
 TCKI  
} 2.Eu+*UC  
>.O*gv/_  
ok>P [ &!  
/* `m@]  
**TestMethod.java
#1jtprc  
*/ SCh7O}  
package NetFox; a._^E/EV  
%$Jqt  
V
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public class TestMethod { 8`inRfpY  
cdJ`Gk  
]EVe@  
public TestMethod() ^!o1l-Y^gr  
{ ///xx/weblogic60b2_win.exe !7kLFW  
try{ H81.p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PX69  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RlslF9f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @!&Jgg53G  
fileFetch.start(); Y( V3PnH  
} LG Y!j_bD  
catch(Exception e){e.printStackTrace ();} _8x'GK tU  
;vI*ThzdD  
|auX*hb9  
} 1O]5/Eu  
f1CMR4D  
hP4)8>  
public static void main(String[] args) rAlh& ?X  
{ i!.I
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new TestMethod(); Wlr&g xZ  
} h=K36a)  
} a*W_fxb  
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