http断点续传简单实现（java)

/* G Y ]bw  
**SiteFileFetch.java ytGcigw(P  
*/ ,dk!hm u  
package NetFox; tsTCZ);(  
import java.io.*; =qTmFszT  
import java.net.*; 4}HY= 0Um  
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public class SiteFileFetch extends Thread { TzY[-YlvF  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I.}E#f/A'  
long[] nStartPos; //开始位置 eN]9=Y~-K  
long[] nEndPos; //结束位置 w'D=K_h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 64-;| k4F  
long nFileLength; //文件长度 p#(5 ;  
boolean bFirst = true; //是否第一次取文件 h>'Mh;+  
boolean bStop = false; //停止标志 6<C|O-  
File tmpFile; //文件下载的临时信息 _QOZ`st  
DataOutputStream output; //输出到文件的输出流 ]EPFyVt~3  
nx'D&,VX  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kEM|;&=_  
public SiteFileFetch(SiteInfoBean bean) throws IOException uY|-: =  
{ =ET|h}I  
siteInfoBean = bean; Wi{ jC?2Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EJ`"npU  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n[`FoY  
if(tmpFile.exists ()) /q>1X!Z  
{ UgZuEfEGve  
bFirst = false; OuF%!~V  
read_nPos(); TW}nO|qw  
} c'~6 1HA<  
else UB1/0o  
{ ?T <2Cl'C  
nStartPos = new long[bean.getNSplitter()]; 6` @4i'.  
nEndPos = new long[bean.getNSplitter()]; %oE3q>S$en  
} J PK
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} ^8eu+E.{  
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public void run() jLG Q^v"  
{ 8!(09gW'>  
//获得文件长度 VsM~$ )  
//分割文件 JQ)w/@Vu=  
//实例FileSplitterFetch ;4ETqi9  
//启动FileSplitterFetch线程 m<uBRI*I  
//等待子线程返回 I7q}<"`
 
try{ tjTnFP/=  
if(bFirst) pw5uH  
{ Dm0Ts~  
nFileLength = getFileSize(); +:?"P<'  
if(nFileLength == -1) wXnluE  
{ )4BLm  
System.err.println("File Length is not known!"); VwrHD$  
} ii:E>O(0B  
else if(nFileLength == -2) ;XXB^,  
{ I[v6Y^{q  
System.err.println("File is not access!"); %^CoWbU  
} lo:{T_ay  
else z->[:)c  
{ qTUyax  
for(int i=0;i<nStartPos.length;i++) qz<>9n@o  
{ OkaNVTB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Gm2q`ki  
} H!yqIh  
for(int i=0;i<nEndPos.length-1;i++) /f0*NNSat-  
{ QlCs,bT  
nEndPos = nStartPos[i+1]; VuWBWb?0Q  
} .>Fy ]Cqoh  
nEndPos[nEndPos.length-1] = nFileLength; r0fxEYze&  
} yO`HL'SMo  
} 85GU~.  
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c Y(2}Ay  
//启动子线程 5b5Hc Inu
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :@8N${7`$A  
for(int i=0;i<nStartPos.length;i++) 14 Toi  
{ VHihC]ks,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i~0x/wSl_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3"HW{
=  
nStartPos,nEndPos,i); $\A=J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L
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fileSplitterFetch.start(); waI:w,  
} 'Wz`P#/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +<1MY'>y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zt|DHVy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gONybz6]  
nEndPos = " + nFileLength); ;S.o`z1GI  
// fileSplitterFetch[nPos.length-1].start(); kzuI<DW  
.ZK^kcyA  
s7>a  
//等待子线程结束 A4>
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//int count = 0; (764-iv(  
//是否结束while循环 P/XCaj3a[  
boolean breakWhile = false; 'V#$PZx  
fS#I?!*}  
6(0ME$  
while(!bStop) j|Hyv{sM  
{ ]w;!x7bU(  
write_nPos(); 9 m`VIB  
Utility.sleep(500); |%l&H/  
breakWhile = true; p]E\!/  
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for(int i=0;i<nStartPos.length;i++) =)mA.j}E2  
{ I->BDNk  
if(!fileSplitterFetch.bDownOver) ^ 9`O ^  
{ =dM'n}@U  
breakWhile = false; 1@W*fVn  
break; &=S<StH  
} J=sj+:GS  
} _ ,~D]JYE  
if(breakWhile) !/RL.`!>  
break; QopA'm  
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k(23Zt]  
//count++; &6q67  
//if(count>4) Rw!wfh_+  
// siteStop(); #m;|QWW  
} O@-|_N*;K  
{ d|lN:B  
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System.err.println("文件下载结束！"); p%ZOLoc)Y  
} 5BRZpCb  
catch(Exception e){e.printStackTrace ();} ' |Ia-RbX  
} Pof]9qE-y  
}LTyXo  
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//获得文件长度 ;@$v_i  
public long getFileSize() GA+#'R  
{ '"M9`@Y3^  
int nFileLength = -1; _A]=45cn~  
try{ s9F{UN3  
URL url = new URL(siteInfoBean.getSSiteURL()); k!)Pl,nJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'D&[Y)f^  
httpConnection.setRequestProperty("User-Agent","NetFox"); |B~^7RHXo  
|$+ xVi8  
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int responseCode=httpConnection.getResponseCode(); X(M|T]`b:  
if(responseCode>=400) G{]tB w  
{ >1S39n5z.  
processErrorCode(responseCode); =s/UF_JN  
return -2; //-2 represent access is error we}G%09L  
} '<-F
3  
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String sHeader; Cr>YpWm  
9AP."RV  
![Ll$Lr  
for(int i=1;;i++) 9gQ ]!Oq  
{ T7#}&>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hA:RVeS{  
//Utility.log(in.readLine()); o_R_  
sHeader=httpConnection.getHeaderFieldKey(i); ffI z>Of:  
if(sHeader!=null) ,0\Pr  
{ d8ck].m=  
if(sHeader.equals("Content-Length")) Aw"Y_S8.  
{ /ht-]Js$G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aaRc?b'/  
break; uRCZGg&V?#  
} 4#Cm5xAt6  
} ?M9?GodbP.  
else JrNqS[c/  
break; hmp!|Q[)  
} :
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} :J;&Z{  
catch(IOException e){e.printStackTrace ();} SbK6o:[  
catch(Exception e){e.printStackTrace ();} =QS%D*.|D  
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Utility.log(nFileLength); D*}_

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return nFileLength; w
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} Ju"K"  
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//保存下载信息（文件指针位置） U^ ;H{S  
private void write_nPos() ;Q\MH t*  
{ 6Ij'z9nJw  
try{ ;Z!x\{-L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9^g?/8  
output.writeInt(nStartPos.length); I4(z'C  
for(int i=0;i<nStartPos.length;i++) 2F#DJN#  
{  1 .Nfl@]  
// output.writeLong(nPos); >SHP,><H/  
output.writeLong(fileSplitterFetch.nStartPos); \V%l.P4>e  
output.writeLong(fileSplitterFetch.nEndPos); m<I>NYfE  
} <_3OiU=w  
output.close(); *IQQsfL)  
} ]
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catch(IOException e){e.printStackTrace ();} $A^OP{  
catch(Exception e){e.printStackTrace ();}
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} GZzBATx  
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//读取保存的下载信息（文件指针位置） ;!pSYcT,  
private void read_nPos() 4_W*LG~2s  
{ )MeeF-Ad6  
try{ 6H^=\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Dks"(0g  
int nCount = input.readInt();
_
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nStartPos = new long[nCount]; :rSCoi>K  
nEndPos = new long[nCount]; ~%!"!Z4  
for(int i=0;i<nStartPos.length;i++) 75W@B}dZd  
{ WwF2Ry^a  
nStartPos = input.readLong(); cI (}  
nEndPos = input.readLong(); Wxa</n8S[n  
} sUz,F8G  
input.close(); '#NDR:J"  
} t~M0_TnXlP  
catch(IOException e){e.printStackTrace ();} :wY(</H  
catch(Exception e){e.printStackTrace ();} v{;^>"5o  
} bj,cU)t0  
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"
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private void processErrorCode(int nErrorCode) se*!OiOt  
{ g=e~YM85  
System.err.println("Error Code : " + nErrorCode); e'T|5I0K  
} (w1$m8`=  
s(pNg?R  
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//停止文件下载 Qb#iT}!p%  
public void siteStop() vVf%wei^#  
{ TpRI+*\  
bStop = true; MQMc=Z4d  
for(int i=0;i<nStartPos.length;i++) bkS-[rW  
fileSplitterFetch.splitterStop(); e/R$Sfj
]  
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} ]N{jF$  
} :&J1#% t  
//负责部分文件的抓取 ,'%*z  
**FileSplitterFetch.java *:"p*qV*  
*/ 4uE|$  
package NetFox; +wGFJLHJ  
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import java.io.*; }ws(:I^  
import java.net.*; @y8) "m"  
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public class FileSplitterFetch extends Thread { K$c?:?wmo  
!|~yf3  
A`nzqe#(1  
String sURL; //File URL 46D_K  
long nStartPos; //File Snippet Start Position =)f5JwZPG  
long nEndPos; //File Snippet End Position 6r)B|~,OA  
int nThreadID; //Thread's ID yX%NFXD  
boolean bDownOver = false; //Downing is over <
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boolean bStop = false; //Stop identical l0lvca=;  
FileAccessI fileAccessI = null; //File Access interface /)<Xoa  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +Uxtxl'  
{ PQXCT|iJ  
this.sURL = sURL; an)Z.x  
this.nStartPos = nStart; ]23+ d/  
this.nEndPos = nEnd; Y2W{?<99  
nThreadID = id; ZY*_x)h+#7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (97&mhs3  
} (l}nwyh5  
#&snl  
=8AL>:_  
public void run() <])kO`
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{ R= .UbY  
while(nStartPos < nEndPos && !bStop) O'S9y  
{ LF ;gdF%@  
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try{ 
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URL url = new URL(sURL); eA-$TSWh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o,!W,sx_  
httpConnection.setRequestProperty("User-Agent","NetFox"); E
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String sProperty = "bytes="+nStartPos+"-"; j`QXl  
httpConnection.setRequestProperty("RANGE",sProperty); Sr+ &  
Utility.log(sProperty); %Mf3OtPiJW  
&W%fsy<  
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InputStream input = httpConnection.getInputStream(); q3ebps9^  
//logResponseHead(httpConnection); wDKA1i%G  
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>S@><[C  
byte[] b = new byte[1024]; Q&vU|y  
int nRead; 6\RZ[g
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w_*$wVl
 
{ O +Xu?W]  
nStartPos += fileAccessI.write(b,0,nRead); +kx#"L:  
//if(nThreadID == 1) eKe[]/}e9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4ok
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} %";ap8J04F  
+<'>~lDg  
hy"=)n(  
Utility.log("Thread " + nThreadID + " is over!"); `gdk,L]  
bDownOver = true; v
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//nPos = fileAccessI.write (b,0,nRead); }i52MI1-XP  
} *R8P brN  
catch(Exception e){e.printStackTrace ();} oiItQ4{<  
} !_?#f|  
} 6t'vzcQs  
R]NCD*~  
KP CZiu7  
//打印回应的头信息 LT:8/&\  
public void logResponseHead(HttpURLConnection con) FrhI[D  
{ 86W.z6  
for(int i=1;;i++) &G_XgQsg{  
{ }*VRj;ff  
String header=con.getHeaderFieldKey(i); |M|>/
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if(header!=null) bf/z T0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UxvT|~"  
Utility.log(header+" : "+con.getHeaderField(header)); =W"9a\m  
else Oe&gTXo  
break; K%YR; )5A  
} C:RA(
  
} WnQ+  
:U6Q==B$_  
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public void splitterStop() >
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{ V-lp';bD  
bStop = true; Mc6v  
} h! wd/jR  
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} gt!tDu  
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/* 5$c*r$t_RK  
**FileAccess.java ]f*.C9Y  
*//文件访问(定位，写) +krDmU9(  
package NetFox; [N0"mE<  
import java.io.*; (4IH%Ez){  
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public class FileAccessI implements Serializable{ gqDSHFm:  
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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 6o~CX  
RandomAccessFile oSavedFile; a[RqK#  
long nPos; A:V/i:IZfR  
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public FileAccessI() throws IOException U)D}J_Zi(  
{ +,J!xy+~,  
this("",0); uOb}R   
} Z+ )<FX  
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public FileAccessI(String sName,long nPos) throws IOException YRU#/TP  
{ _s+_M+
@et  
oSavedFile = new RandomAccessFile(sName,"rw"); cfL:#IM  
this.nPos = nPos; MG4(,"c!  
oSavedFile.seek(nPos); 6eW9+5oL  
} Z"E2ZSa0  
c@{M),C~E  
IaGF{O3.  
public synchronized int write(byte[] b,int nStart,int nLen) 59k-,lyU,  
{ TJs~}&L  
int n = -1; {#&j
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try{ gk4DoOj#P  
oSavedFile.write(b,nStart,nLen); .}3K9.hkr  
n = nLen; z/|tsVK  
} >C -N0H
 
catch(IOException e) R?}<CjI  
{ S{zl<>+  
e.printStackTrace (); xDIl  
} '|nA
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return n; r_3=+  
} Y{2L[5_1  
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} 7 '{wl,u  
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/* DpQ:U5j  
**SiteInfoBean.java [wcp2g3Px  
*/ ;D}E/'=  
package NetFox; lA,*]Mr~  
YH{FTVOt{C  
3'[ g2JR  
public class SiteInfoBean { .%_=(C<E  
rG{,8*  
pR3K~bx^  
private String sSiteURL; //Site's URL XvkFP'%i/  
private String sFilePath; //Saved File's Path )0{ZZ-beG  
private String sFileName; //Saved File's Name mh8)yy5\  
private int nSplitter; //Count of Splited Downloading File &Tk@2<5=  
@!%HEs!# #  
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public SiteInfoBean() A'T: \Wl  
{//nSplitter的缺省值为5 en29<#8TO  
//default value of nSplitter is 5 {r1}ACw{  
this("","","",5); UKf0cU  
} Ia-nA|LBxI  
z&Lcl{<MA  
>{k0N@_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F"t.ND
 
{ U46Z~B  
sSiteURL= sURL; sF p% T4j  
sFilePath = sPath; a/U4pSug  
sFileName = sName; h2vD*W  
this.nSplitter = nSpiltter; SaA-Krn  
|\SwZTr  
lM[FT=M  
} }&LLo  
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public String getSSiteURL() <@+{EK'`q  
{ ~P!%i9e_  
return sSiteURL; 8Xz \,}$O  
} |:5[`  
r*t\F&D  
rY]QTS">o  
public void setSSiteURL(String value) r$&WwH2^  
{ VZr AZV^c  
sSiteURL = value; ,\D*=5  
} IeGVLC
  
2g%p9-MO]I  
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public String getSFilePath() "%K[kA6  
{ FuFA/R=x/  
return sFilePath; *hkNJ  
} zl@hg<n  
"[\),7&03  
iKE
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public void setSFilePath(String value) U].3vju`c  
{ oPR?Ar  
sFilePath = value; SJ8|~,vL  
} Oi\,clR^[o  
G*rlU  
swG!O}29OX  
public String getSFileName() 2q%vd
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{ MLt'tzgl  
return sFileName; dR >hb*kJ  
} yIma7H@=L  
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nBGcf(BE.$  
public void setSFileName(String value) _#TbOfu  
{ d2Ox:| <)  
sFileName = value; Q ;$NDYV1  
} obSLy Ed  
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/@+[D{_Fw  
public int getNSplitter() tz/NR/[  
{ gR@,"6b3  
return nSplitter; yPVK>em5  
} #]lK!:  
]%I|C++
0  
t(=Z@9)]4F  
public void setNSplitter(int nCount) & _mp!&5XV  
{ 7aJ:kumDZ  
nSplitter = nCount; [M&.'X  
} Rge\8H/z  
} =x}p>#o,J  
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/* nsyeid*  
**Utility.java u]s}@(+.  
*/ ==Bxv:6  
package NetFox; ,_RPy2N  
:x36Z4:  
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public class Utility { xaW9Sj0ZM  
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QLOcgU^  
public Utility() Q'Vejz/  
{ <
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} +/DT#}JE  
A!^gF~5  
//线程睡眠 HR$;QHl~F  
public static void sleep(int nSecond) Ygfv?  
{ b]@@
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try{ >0.a#-u^  
Thread.sleep(nSecond); ?$0t @E  
} 8 ;o*c6+  
catch(Exception e) l[M?"<Ot;  
{ ;'4HR+E"  
e.printStackTrace (); ~<q^4w.=7C  
} (K3eb  
} ^ 9FRI9
?  
<F<jx"/)  
//日志 %M u$0~ct"  
public static void log(String sMsg) l|5;&(Y+s  
{ 6>j0geFyE2  
System.err.println(sMsg); to#N>VfD  
} .f
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FFpG>+*3  
Jj,fdP#\  
public static void log(int sMsg) Vc$y^|=  
{ ^=7XA894  
System.err.println(sMsg); i'`[dwfS  
} L2\NTNY  
} K5EU?J&  
4$_:a?9  
p@jwHlX  
/* "*Gp@  
**TestMethod.java ~dlp
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*/ z 3N'Xk  
package NetFox; E% d3}@  
pW1(1M)[%Z  
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public class TestMethod { c@/K}  
t$-!1jq  
o2W^!#]=
 
public TestMethod() eGj[%pk  
{ ///xx/weblogic60b2_win.exe 5Za%EaW%G  
try{ g~]?6;uu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k07pI<a?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D%!GY1wdn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !FHm.E_>  
fileFetch.start(); Q+a"Z^Z|  
} [ %6(1$Ih  
catch(Exception e){e.printStackTrace ();} D2MWrX  

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} ]8dzTEjk  
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public static void main(String[] args) IHcR/\mz  
{ Ucd~-D  
new TestMethod(); Qkb=KS%z  
} 55Ag<\7  
} }b=Cv?Zg$m  
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