http断点续传简单实现（java)

/* #q>\6} )  
**SiteFileFetch.java ^ FM  
*/ 8 C9ny}  
package NetFox; /=T:W*C  
import java.io.*; 7xFZJ#  
import java.net.*; lwz\"8  
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public class SiteFileFetch extends Thread { @t;726  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -L<FVB  
long[] nStartPos; //开始位置 -$X4RS  
long[] nEndPos; //结束位置 h#c7v!g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )TEm1\  
long nFileLength; //文件长度 /::Y &&$f  
boolean bFirst = true; //是否第一次取文件 4U16'd  
boolean bStop = false; //停止标志 WEJ-K<A(  
File tmpFile; //文件下载的临时信息 !iq|sXs  
DataOutputStream output; //输出到文件的输出流 #G_'5{V  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8.>himL  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]G D` f  
{ \ @[Q3.VX  
siteInfoBean = bean; ,p#r; O<O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o@7U4#E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c%bzrYQvA;  
if(tmpFile.exists ()) !{{gL=_@  
{ |fIyq}{7  
bFirst = false; f$tm<:)Y  
read_nPos(); T:Ovh.$  
} 7>f"4r_r6<  
else u:f.;?  
{ i]s%tEZ1  
nStartPos = new long[bean.getNSplitter()]; Y%?*Lj|  
nEndPos = new long[bean.getNSplitter()]; bdY:-8!3  
} nt+OaXe5D  
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} V#b=mp  
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public void run() Zxhbnl6  
{ YaL:6[6  
//获得文件长度 OScqf]H  
//分割文件 s2GF*{  
//实例FileSplitterFetch (KwC,0p  
//启动FileSplitterFetch线程 =Xg/[J%  
//等待子线程返回 0:>hK\F#  
try{ X:I2wJDs\  
if(bFirst)  jr_z ?  
{ f0j]!g  
nFileLength = getFileSize(); <
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if(nFileLength == -1) GmaNi  
{ lGBg8/[  
System.err.println("File Length is not known!"); #9Jr?K43  
} n>R(e>  
else if(nFileLength == -2) ,lStT+A  
{ ,i??}Wm5G  
System.err.println("File is not access!"); .}v" `>x  
} T1*.3_wtP  
else k].swvIi  
{ D7T|K :F)  
for(int i=0;i<nStartPos.length;i++) E>f
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{ l)dE7$H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $B_%MfI  
} gua7<z6=eh  
for(int i=0;i<nEndPos.length-1;i++) (ie%zrhS  
{ {wsJ1v8!  
nEndPos = nStartPos[i+1]; =*jFaj  
} ""XAUxo  
nEndPos[nEndPos.length-1] = nFileLength; *U]&a^N  
} xY#J((-iH  
} (3lA0e`Y  
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//启动子线程 [U8/nT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V-@4s}zX  
for(int i=0;i<nStartPos.length;i++) e,VF;Br  
{ ,z>-_HOnw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~59lkr8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ooUVVp  
nStartPos,nEndPos,i); JO0o@M5H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E:ci/09wD  
fileSplitterFetch.start(); Ul9^"o  
} K%+4M#jj5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W dD889\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oKCy,Ot<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R-9o3TPa  
nEndPos = " + nFileLength); m7g*zu2#  
// fileSplitterFetch[nPos.length-1].start(); GT)7VFrL  
@$n $f  
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//等待子线程结束 yDK
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//int count = 0; 7/51_=%kR  
//是否结束while循环 P1T{5u!T  
boolean breakWhile = false; pR93T+X  
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while(!bStop) J sz=5`  
{ g:a[N%[C  
write_nPos(); W h
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Utility.sleep(500); ;"x+V gS'  
breakWhile = true; E V)H>kM  
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for(int i=0;i<nStartPos.length;i++) H"8B4~*7H  
{ tEvDAI} 5  
if(!fileSplitterFetch.bDownOver) 7~XA92  
{ vm_]X{80
;  
breakWhile = false; W/xPVmnV  
break; S-q"'5>  
} t#|R"Q#  
} CvE^t#Bok  
if(breakWhile) *c[
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break; R$hIgw+p[  
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; Z7!BU  
//count++; h7q{i|5  
//if(count>4) !zF07.(E  
// siteStop(); 5l1R")0`t_  
} 7
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System.err.println("文件下载结束！"); _7Y-gy#\a  
} =3QhGFd  
catch(Exception e){e.printStackTrace ();} (b//YyqN  
} >pLJ ,Z  
)MF@'zRK  
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//获得文件长度 ||QK)$"  
public long getFileSize() O}Pqbx&  
{ )5~T%_  
int nFileLength = -1; b)Da6fp  
try{ 7uL.=th'  
URL url = new URL(siteInfoBean.getSSiteURL()); SA}Dkt&,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = NZgbl  
httpConnection.setRequestProperty("User-Agent","NetFox"); f0sLe 3  
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int responseCode=httpConnection.getResponseCode(); heou\;GI"  
if(responseCode>=400) +5*bU
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{ fEXFnQ#  
processErrorCode(responseCode); \ opM}qZ  
return -2; //-2 represent access is error e[u}Vf  
} bKM*4M=k  
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String sHeader; d;YKw1  
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for(int i=1;;i++) b.RU%Y#>\  
{ /Tm+&Jd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2A~o)7JaZ  
//Utility.log(in.readLine()); \]f+{d-&  
sHeader=httpConnection.getHeaderFieldKey(i); 
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if(sHeader!=null) {:!>Y1w>  
{ gR# k'  
if(sHeader.equals("Content-Length")) M9R'ONYAa  
{ Eqz|eS*6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (JlPe)Q5  
break; ]VKQm(,0  
} Ut\:jV=f  
} A/I\MN|  
else 0l[52eZ/  
break; 4vWiOcJF!O  
} PB$beQ  
} -`XS2  
catch(IOException e){e.printStackTrace ();} =YgH-{  
catch(Exception e){e.printStackTrace ();} 9h\RXVk{tA  
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Utility.log(nFileLength); ao9#E"BfM  
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return nFileLength;
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} lb't
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//保存下载信息（文件指针位置） gjG SI'M0B  
private void write_nPos() $3 -QM  
{ ~M^[  
try{ r_$*euh@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @,.D]43  
output.writeInt(nStartPos.length); _J6 Xq\  
for(int i=0;i<nStartPos.length;i++) kh.P)h'9  
{ MZQDFuvDxZ  
// output.writeLong(nPos); W.[!Q`  
output.writeLong(fileSplitterFetch.nStartPos); W..*!UGl  
output.writeLong(fileSplitterFetch.nEndPos); ^@*`vz^_  
} mTtaqo_Bh  
output.close(); 46D`h!7L  
} u~M$<|;  
catch(IOException e){e.printStackTrace ();} v[ML=pL  
catch(Exception e){e.printStackTrace ();} 4Z%1eOR9V  
} /A,w{09G  
. KLEx]f.  
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//读取保存的下载信息（文件指针位置） p=nbsS~":  
private void read_nPos() 63l& ihj  
{ f4P({V  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C\5G43`  
int nCount = input.readInt(); QyVAs;  
nStartPos = new long[nCount]; )S+fc=  
nEndPos = new long[nCount]; vx($o9  
for(int i=0;i<nStartPos.length;i++) XjL3Ar*  
{ yYJ_;Va  
nStartPos = input.readLong(); J1I,;WGf  
nEndPos = input.readLong(); _"@:+f,  
} Up?RN%gq  
input.close(); <!>\ n\A  
} tlp,HxlP  
catch(IOException e){e.printStackTrace ();} ZN)EbTpc\a  
catch(Exception e){e.printStackTrace ();} <(>t"<  
} 9.\SeJ8c  
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private void processErrorCode(int nErrorCode) WC<[<uI*  
{ W=^.s>7G  
System.err.println("Error Code : " + nErrorCode); wl]3g  
} _"
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//停止文件下载 I?g}q,!]  
public void siteStop() Cs>`f,o  
{ Sk7R;A  
bStop = true; -)(=~|,Pq/  
for(int i=0;i<nStartPos.length;i++) ~|S0E:*.  
fileSplitterFetch.splitterStop(); (CIcM3|9C  
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} }#D=Rf?2\P  
} ;dUKFdKH}  
//负责部分文件的抓取 }ZVond$y4  
**FileSplitterFetch.java b)'CP Cu*  
*/ eg/itty  
package NetFox; ].xSX0YQ%  
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import java.io.*; /jJD {  
import java.net.*; *]U`]!Esp  
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public class FileSplitterFetch extends Thread { &,G2<2_b  
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String sURL; //File URL :lo5,B;k  
long nStartPos; //File Snippet Start Position lFt!  
long nEndPos; //File Snippet End Position xk~gGT&  
int nThreadID; //Thread's ID *nU5PSs  
boolean bDownOver = false; //Downing is over 0yC~"u[N Y  
boolean bStop = false; //Stop identical `.pEI q^  
FileAccessI fileAccessI = null; //File Access interface a~jb%i_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 13F]7l-#  
{ VnW6$W?g  
this.sURL = sURL; ~{lb`M^]h  
this.nStartPos = nStart; X<8|uP4  
this.nEndPos = nEnd; I ==)a6^
 
nThreadID = id; 'qT;Eht5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +Xw%X3o)  
} dQ{qA(m  
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public void run() $,by!w'e:l  
{ ?:9y !Q=  
while(nStartPos < nEndPos && !bStop) Vv+nq_  
{ 7<]&pSt=  
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try{ K_L7a>Fr  
URL url = new URL(sURL); $7AsMlq[(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I1>f2/$z*  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cydo~/  
String sProperty = "bytes="+nStartPos+"-"; u|}\
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httpConnection.setRequestProperty("RANGE",sProperty); u~uz=Yse  
Utility.log(sProperty); L@T/4e./  
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InputStream input = httpConnection.getInputStream(); H6`k%O*  
//logResponseHead(httpConnection); TfZM0Wz  
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byte[] b = new byte[1024]; 6w &<j&V  
int nRead; Hb*Z_s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +3.9)w  
{ `&c[s%0  
nStartPos += fileAccessI.write(b,0,nRead); XlF,_  
//if(nThreadID == 1) vaF1e:(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fpQFNV  
} wT!?.Y)aj  
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Utility.log("Thread " + nThreadID + " is over!"); %TN$   
bDownOver = true; ,YM=?No  
//nPos = fileAccessI.write (b,0,nRead); rR@]`@9  
} ]_B<K5  
catch(Exception e){e.printStackTrace ();} %%X/gvaJ  
} }Y!V3s1bm  
} iSf%N>y'K  
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//打印回应的头信息 XuJyso9kA  
public void logResponseHead(HttpURLConnection con) d4IQ;u  
{ KB~[nZs7  
for(int i=1;;i++) 'vVt^h2  
{ }\<=B%{  
String header=con.getHeaderFieldKey(i); *3Lo[GE>  
if(header!=null) ;q-c[TZC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '{cND  
Utility.log(header+" : "+con.getHeaderField(header)); UUWRC1EtI  
else >b\|%=(x!*  
break; v0) %S  
} E!}'cxb^  
} g0biw?  
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public void splitterStop() BDfMFH[1  
{ X_X7fRC0  
bStop = true; gHp4q!SJ7  
} yx?oxDJg  

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} 1d49&-N  
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-ABj>y[  
/* U*K4qJ6U  
**FileAccess.java )( 3)^/Xz  
*//文件访问(定位，写) t9<BQg  
package NetFox; }!fIY7gv  
import java.io.*; a+z>pV|  
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public class FileAccessI implements Serializable{ WVQHb3Pe0  
7n .A QII  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C\"C12n{  
RandomAccessFile oSavedFile; %6fnL~A  
long nPos; <k1muSe  
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public FileAccessI() throws IOException k"[AV2UW1  
{ *fi`DiO  
this("",0); ,.{M1D6'R`  
} W="pu5q$5  
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public FileAccessI(String sName,long nPos) throws IOException vRaxB  
{ 4 w*m]D{  
oSavedFile = new RandomAccessFile(sName,"rw"); >N! Xey  
this.nPos = nPos; E5S(1Z}]p{  
oSavedFile.seek(nPos); T)22P<M8  
} FB?V<x  
uh9b!8  
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public synchronized int write(byte[] b,int nStart,int nLen) z
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{ "(H%m9K  
int n = -1; Fi+DG?zu  
try{ G$*=9`  
oSavedFile.write(b,nStart,nLen); jm&[8ApW  
n = nLen; .3+8Ip#z  
} &Pv$nMB$I  
catch(IOException e) ^K[xVB(&  
{ ]Y?ZUSCJ  
e.printStackTrace (); -|#/KKF  
} JK{2hr_a  
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return n; e 0$m<5  
} B;Z _'.i,d  
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} VZamR}x  
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/* r.LOj6c  
**SiteInfoBean.java ?:GrM!kq76  
*/ zBI2cB8;P  
package NetFox; R^@`]dX$  
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public class SiteInfoBean { uUBUUr  
WM$Z?CN%KB  
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private String sSiteURL; //Site's URL o^uh3,.  
private String sFilePath; //Saved File's Path Ia9!ucN7DA  
private String sFileName; //Saved File's Name ?o]
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private int nSplitter; //Count of Splited Downloading File _^eA1}3  
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public SiteInfoBean() 'Q7t5v@FF  
{//nSplitter的缺省值为5 jfvlkE-uK  
//default value of nSplitter is 5 |d42?7}  
this("","","",5); Kzt:rhiB  
} rmX5-k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9l&G2o  
{ |tY6+T}  
sSiteURL= sURL; S:2 xm8 i  
sFilePath = sPath; H`3w=T+I  
sFileName = sName; <VN< ~sz  
this.nSplitter = nSpiltter; DB jUHirK  
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} "AWk jdj  
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public String getSSiteURL() a(JtGjTf&  
{ y </i1qM  
return sSiteURL; CpgaQG^  
} Ym]rG 4  
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public void setSSiteURL(String value) )i-`AJK-'v  
{ YSZ
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sSiteURL = value; oqK
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} ``Um$i~e%  
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public String getSFilePath() _ -ec(w~/  
{ `Sj8IxO  
return sFilePath; Frhm4H%,_R  
} bx".<q(  
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public void setSFilePath(String value) A}"uEk
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{ oY@]&A^ah  
sFilePath = value; Oh}@c~7;  
} T(qHi?Y  
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public String getSFileName() I= z+`o8  
{ .lcgM  
return sFileName; jd+HIR  
} pAEJ=Te  
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public void setSFileName(String value) 4 >D5t)254  
{ fG7-0
7  
sFileName = value; PO2]x:  
} [9p@uRE  
mL,{ZL ^  
l4^8$@;s  
public int getNSplitter() ,6
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{ hn/SS  
return nSplitter; Qbj:^{`>(  
} t6+>Zr  
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public void setNSplitter(int nCount) y2C/DyuAY|  
{ \g@jc OKU  
nSplitter = nCount; L\<J|87p?  
} %cMayCaI!@  
} J=DD/Gp  
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/* A<g5:\3  
**Utility.java JDMsco+j5  
*/ Od]wh  
package NetFox; c$3ZEe
 
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public class Utility {
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public Utility() 
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{ |1 LKdP  
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} OoAZ t  
bNz2Uo!0K  
//线程睡眠 _ID =]NJ_  
public static void sleep(int nSecond) /^Lo@672  
{ ,PyPRPk  
try{ rg+3pX\{  
Thread.sleep(nSecond);  M Xl!  
} \cq.M/p  
catch(Exception e) q/YO5>s15  
{ =0mGfTc  
e.printStackTrace (); o Bp.|8-  
} 5s2/YG=  
} >5]w\^QN9_  
"[]J[!}x  
//日志 P,Rqv)}X  
public static void log(String sMsg) mZ t:  
{ C;!h4l7L  
System.err.println(sMsg); P~*v}A  
} <Xj ,>2m;  
qS2]|7q?Tc  
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public static void log(int sMsg) qT_E=)
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{ ?B,B<@='%  
System.err.println(sMsg); s}Sxl0  
} x1*@PiO,.  
} 8"S? Toqq  
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/* 
_
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**TestMethod.java s=|&NlO$  
*/ 7wc{.~+  
package NetFox; S{ !m})1?  
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Sst`*PX:  
public class TestMethod { l{x?i00tAS  
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public TestMethod() 32V,25 (`5  
{ ///xx/weblogic60b2_win.exe 1]XIF?_Dm  
try{ j2|!h%{nI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lf9_!`DGV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U^X8{,8O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -?<L"u  
fileFetch.start(); 5Bc)QKh`l|  
} _`Sz}Yk  
catch(Exception e){e.printStackTrace ();} #3u471bp  
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C!" .[3  
} /waZ9  
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public static void main(String[] args) ?`O Dt]s  
{ *Cgd?*\7  
new TestMethod(); *:A)j?(  
} ~d?\rj3=  
} 4==LtEp  
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