http断点续传简单实现（java)

/* /]Md~=yNp  
**SiteFileFetch.java | rtD.,m   
*/ oIzj,v8$  
package NetFox; y
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import java.io.*; mnX2a  
import java.net.*; :KP@RZm  
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public class SiteFileFetch extends Thread { H=
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SiteInfoBean siteInfoBean = null; //文件信息Bean WO>nIo5Y  
long[] nStartPos; //开始位置 xr Jg\to{i  
long[] nEndPos; //结束位置 @,my7?::oM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CxW>~O:  
long nFileLength; //文件长度 c]o'xd,T8\  
boolean bFirst = true; //是否第一次取文件 {]@= ijjf  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 "e>;'%W  
DataOutputStream output; //输出到文件的输出流 vw/J8'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Flm%T-Dl  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~4Fvy'  
{ >tV{Pd1  
siteInfoBean = bean; sBg.u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KU(&%|;g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S g![Lsj  
if(tmpFile.exists ()) .g<DD)`  
{ z,p~z*4  
bFirst = false; 0pd'93C  
read_nPos(); 3~{:`[0Q  
} ={&j07,*a  
else H40p86@M  
{ *P=VFP  
nStartPos = new long[bean.getNSplitter()]; E4/Dr}4  
nEndPos = new long[bean.getNSplitter()]; 3;{kJQ
 
} mNTzUoZF'@  
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} ^k">A:E2  
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public void run() qfm|@v|De5  
{ K?1W!fY  
//获得文件长度 /7F:T[  
//分割文件 _Q4)X)F  
//实例FileSplitterFetch dcN22A3  
//启动FileSplitterFetch线程 %l[( Iw  
//等待子线程返回 N S[l/0F&  
try{ >}i E(  
if(bFirst) }|NCboM^_  
{ Y.rsR6  
nFileLength = getFileSize(); e6$WQd`O  
if(nFileLength == -1) y_-0tI\J  
{ M!^az
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System.err.println("File Length is not known!"); 5Yq@;e  
} ?%[@Qb=2  
else if(nFileLength == -2) BW*rIn<?G  
{ T:yE(OBf  
System.err.println("File is not access!"); U$z-e/  
} )Y{L&A  
else +',S]Edx  
{ `+:`_4  
for(int i=0;i<nStartPos.length;i++) &d^m 1  
{ S;#'M![8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /@TF5]Ri  
} k,+0u/I  
for(int i=0;i<nEndPos.length-1;i++) "J_9WUN  
{ >_T-u<E  
nEndPos = nStartPos[i+1]; s9DYi~/,  
} g*C7 '  
nEndPos[nEndPos.length-1] = nFileLength; tl^9WG  
} }Oq5tC@$G  
} vV-`jsq20H  
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//启动子线程 Z,Dl` w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M!D3}JRm  
for(int i=0;i<nStartPos.length;i++) Y&Z.2>b
 
{ .|i.Cq8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f(y:G^V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S3Xl  
nStartPos,nEndPos,i); 'e'cb>GnA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @<EO`L)Z  
fileSplitterFetch.start(); {fT6O&br  
} srrgvG,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z5*'{t)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u <v7;dF|s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?J>  
nEndPos = " + nFileLength); M@v.c;Lt  
// fileSplitterFetch[nPos.length-1].start(); Ne1$ee.NE  
Si;H0uPO  
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//等待子线程结束 i5
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//int count = 0; u>a5GkG.  
//是否结束while循环 #BH*Z(  
boolean breakWhile = false; Ry6@VQ"NLb  
{8bSB.?R  
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while(!bStop) -;WGS o  
{ B>P{A7Q  
write_nPos(); pG;U2wE  
Utility.sleep(500); \bvfEP  
breakWhile = true; &E5g3lf  
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for(int i=0;i<nStartPos.length;i++) 0*{%=M  
{ )|#sfHv7  
if(!fileSplitterFetch.bDownOver) gT6jYQ  
{ s&3Vg7B  
breakWhile = false; suDQ~
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break; R.yvjPwJ  
} V+9 MoT?8  
} CB}2j  
if(breakWhile) SSMHoJGm  
break; J)p l|I  
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//count++; LyFN.2q
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//if(count>4) V1B5w_^>h'  
// siteStop(); p9{mS7R9T  
}
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System.err.println("文件下载结束！"); qF;|bF  
} 9V*qQS5<p  
catch(Exception e){e.printStackTrace ();} /hyN;.hpOO  
} *VxgARIL  
i?^L/
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//获得文件长度 z*%q@]ym  
public long getFileSize() B \2SH%\  
{ onxLyx|A  
int nFileLength = -1; toC^LZgZ_6  
try{ L) T (<  
URL url = new URL(siteInfoBean.getSSiteURL()); Qh\60f>0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a<bwzX|.  
httpConnection.setRequestProperty("User-Agent","NetFox"); T1=fNF  
Z4 =GMXj  
*u;Iw{.{  
int responseCode=httpConnection.getResponseCode(); 1#+S+g@#  
if(responseCode>=400) p H2Sbs:Tk  
{ v):Or'$~M  
processErrorCode(responseCode); ji0@P'^;  
return -2; //-2 represent access is error t\7[f >  
} z!9-
:  
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String sHeader; XU(eEnmom  
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for(int i=1;;i++) hM@>q&q_  
{ ]~3V}z,T*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -6B4sZpzD  
//Utility.log(in.readLine()); rmg}N  
sHeader=httpConnection.getHeaderFieldKey(i); 7J<5f)  
if(sHeader!=null) 6qnzBA7  
{ c9h6C  
if(sHeader.equals("Content-Length")) Wvf ^N(  
{ C1QA)E['V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0flRh)[J  
break; [ v*ju!  
} 1yu4emye4  
} [`7ThHX  
else wz%NbLy-  
break; cyz3,3\e  
} r*Ca}Z  
} +QJ#2~pE  
catch(IOException e){e.printStackTrace ();} YNi.SXH  
catch(Exception e){e.printStackTrace ();} 5$C-9  
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Utility.log(nFileLength); +52{-a,>  
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return nFileLength; *0=j?~&  
} *J`O"a  
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//保存下载信息（文件指针位置） Xc&9Glf  
private void write_nPos() Qzw;i8n{  
{ /m

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try{ NTs aW}g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z(CkZll  
output.writeInt(nStartPos.length); "=MeM)K  
for(int i=0;i<nStartPos.length;i++) e$rZ5X  
{ b d!Y\OD
  
// output.writeLong(nPos); t*w/{|yO  
output.writeLong(fileSplitterFetch.nStartPos); 7-fb.V9  
output.writeLong(fileSplitterFetch.nEndPos); }@d@
3  
} \,0oX!<YY  
output.close(); 2<}%kQ`  
} L~
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catch(IOException e){e.printStackTrace ();} h<<v^+m  
catch(Exception e){e.printStackTrace ();} IW] rb/H  
} aK^q_ghh[  
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//读取保存的下载信息（文件指针位置） 6.yu-xm
 
private void read_nPos() x
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{ o?Oc7$+u  
try{ 7HYwLG:\~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @f3E`8  
int nCount = input.readInt(); +v:SM9  
nStartPos = new long[nCount]; AH~E)S  
nEndPos = new long[nCount]; R.<g3"Lm>  
for(int i=0;i<nStartPos.length;i++) {E|$8)58i  
{ e$Pj.>-<=  
nStartPos = input.readLong(); mQ"-,mMI  
nEndPos = input.readLong(); pOoEI+t  
} DZtsy!xA  
input.close(); [ub e6  
} a0H+.W+]  
catch(IOException e){e.printStackTrace ();} 67FWa  
catch(Exception e){e.printStackTrace ();} 7WzxA=*#  
} )zDCu`  
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+9sQZB# (  
private void processErrorCode(int nErrorCode) [j+sC*  
{ >Cq<@$I2EB  
System.err.println("Error Code : " + nErrorCode); mj7#&r,1l  
} G$('-3@i`w  
1T n}
 
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//停止文件下载 gL/9/b4  
public void siteStop() 1EX;MW-p<T  
{ E}Uc7G  
bStop = true; *MW\^PR?  
for(int i=0;i<nStartPos.length;i++) >uEzw4w  
fileSplitterFetch.splitterStop(); &s>Jb?_5Mx  
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} )Hr`MB  
} YKK*ER0  
//负责部分文件的抓取 &s!@29DXR  
**FileSplitterFetch.java 2=!RQv~%  
*/ Y"$xX8o
  
package NetFox; s_p!43\J  
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import java.io.*; <<O$ G7c  
import java.net.*; .O<obq~;C  
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public class FileSplitterFetch extends Thread { C\hM =%  
i SQu#p@  
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String sURL; //File URL -MBxl`JU  
long nStartPos; //File Snippet Start Position [0("Q;Ec[j  
long nEndPos; //File Snippet End Position XW92gI<O  
int nThreadID; //Thread's ID w5 Li&m  
boolean bDownOver = false; //Downing is over @_{=V0  
boolean bStop = false; //Stop identical Bk{]g=DO  
FileAccessI fileAccessI = null; //File Access interface vtJJ#8a]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =($xG#g`  
{ ,|/f`Pl  
this.sURL = sURL; cPQiUU~W@  
this.nStartPos = nStart; YtLt*Ig%  
this.nEndPos = nEnd; ti,d&c_7  
nThreadID = id; Q\0'lQJdy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E' uZA  
} ;}p  
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public void run() n~Lt\K:  
{ ]T) 'Hb  
while(nStartPos < nEndPos && !bStop) _DEjF)S  
{ [()koU#w.  
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try{
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URL url = new URL(sURL); |;{6&S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7_[L o4_  
httpConnection.setRequestProperty("User-Agent","NetFox"); -$Ih@2"6  
String sProperty = "bytes="+nStartPos+"-"; ~)M~EX&pK  
httpConnection.setRequestProperty("RANGE",sProperty); %\:Wi#w>  
Utility.log(sProperty); dqcL]e  
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InputStream input = httpConnection.getInputStream(); a?oI>8*  
//logResponseHead(httpConnection); &uVnZ@o42  
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byte[] b = new byte[1024]; ZYNsHcTY  
int nRead; M D#jj3y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AQ^u  
{ a$fnh3j[  
nStartPos += fileAccessI.write(b,0,nRead); #4;wjcGWw  
//if(nThreadID == 1) qZZK#,Qb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )QJUUn#  
} (**oRwr%  
(^>J&[=  
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Utility.log("Thread " + nThreadID + " is over!"); ?gXp*>Kg[  
bDownOver = true; b#o|6HkW  
//nPos = fileAccessI.write (b,0,nRead); DVeE1Q  
} q1ma%
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catch(Exception e){e.printStackTrace ();} PZzMHK?hP  
} iU:cW=W|M\  
} ?\n> AC  
\ B%+fw  
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//打印回应的头信息 43 :X,\~)  
public void logResponseHead(HttpURLConnection con) 7-V/RChBm  
{ !p/goqT~dY  
for(int i=1;;i++) .jK4?}]  
{ tT._VK]o&R  
String header=con.getHeaderFieldKey(i); *yGGBqd  
if(header!=null) 5`_SN74o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qcRs$-J  
Utility.log(header+" : "+con.getHeaderField(header)); f?)-}\[IR{  
else @E8+C8'  
break; >.D4co>  
} u]G\H!WkQ  
} )YI(/*+]  
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public void splitterStop() ^kSqsT"  
{ 0IWf!Sk ]  
bStop = true; Gp\ kU:}&  
} 4{Z)8;QX  
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} fTX;.M/%   
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/* f<6lf7qzC  
**FileAccess.java /<BI46B\  
*//文件访问(定位，写) *n"{J(Jt`  
package NetFox; d0 /#nz  
import java.io.*; o<!?7g{  
m)D|l1AtF  
t3^&;&[  
public class FileAccessI implements Serializable{ U`s{Jm  
3=;<$+I6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HLi%%"'  
RandomAccessFile oSavedFile; XB5DPx  
long nPos; \.}c9*)  
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public FileAccessI() throws IOException ]
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{ Vf1^4t  
this("",0); Dum9l
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} k==h|\|  
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public FileAccessI(String sName,long nPos) throws IOException h@wgd~X9  
{ HkVB80hv  
oSavedFile = new RandomAccessFile(sName,"rw"); Jfl!#UAD|n  
this.nPos = nPos; 6-ils3&  
oSavedFile.seek(nPos); <=C?e<Y  
} @=f\<"$vt  
3irl (;v  
'/%H3A#L  
public synchronized int write(byte[] b,int nStart,int nLen) {+b7sA3
 
{ k~z Iy;AZ  
int n = -1; g#E-pdY  
try{ pI<f) r  
oSavedFile.write(b,nStart,nLen); l}M!8:UzU  
n = nLen; 1yY0dOoLG)  
} Srd4))2/0  
catch(IOException e) is@?VklnB  
{ 5Jnlz@P9  
e.printStackTrace (); E&:,oG2M  
} <ZR9GlIr  
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return n; q-d:TMkc  
} Y`wSv NU  
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} "5$B>S(Q  
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/* ~WV"SaA)*U  
**SiteInfoBean.java 1[-tD0{H  
*/ JOBhx)E  
package NetFox; [z9Z5sLO  
'@P^0+B!(.  
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public class SiteInfoBean { }\k"n{!"  
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private String sSiteURL; //Site's URL ,~W|]/b<q  
private String sFilePath; //Saved File's Path x'R`. !g3  
private String sFileName; //Saved File's Name Od)C&N=y  
private int nSplitter; //Count of Splited Downloading File 9(wK@  
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public SiteInfoBean() <1M-Ro?5k  
{//nSplitter的缺省值为5 Aq7osU1B  
//default value of nSplitter is 5 >b4eL59  
this("","","",5); !jR=pIfq  
} +^T@sa`[I  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;,e2egC'  
{ BIL Lq8)  
sSiteURL= sURL; jWfa;&Ra  
sFilePath = sPath; u\JNr}bL  
sFileName = sName; Nda *L|  
this.nSplitter = nSpiltter; _zMW=nypdx  
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=_u4=4
 
} hY8reQp1  
VyGJ=[ ]  
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public String getSSiteURL() UFuX@Lu0  
{ $iz|\m  
return sSiteURL; _:27]K:  
} x-3\Ls[I  
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public void setSSiteURL(String value) tIgN$BHR>  
{ cYt!n5w~W  
sSiteURL = value; pz>>)c`  
} 4HA<P6L  

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public String getSFilePath() *;*r8[U}q  
{ rw #$lP  
return sFilePath; J-hbh  
} &:)Wh[  
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public void setSFilePath(String value) n.0fVV-A  
{ ZJs$STJ*  
sFilePath = value; o"#\ >  
}
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[ibu/W$  
~$?ZK]YOrx  
public String getSFileName() M/gGoE{  
{ d>C$+v>  
return sFileName; 'b{]:Y  
} `W*U4?M  
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N?"]  
public void setSFileName(String value) CzEd8jeh7  
{ kPLxEwl  
sFileName = value; W6/yn
 
} D>tR-
  
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public int getNSplitter() LSr]S79N1  
{ ~R92cH>L  
return nSplitter; ,\%c^,HLJ  
} e**qF=HCw  
[HZv8HU|  
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public void setNSplitter(int nCount) "a U aotx  
{ Y/zj[>  
nSplitter = nCount; W:L AP R  
} WI-1)1t  
} '1s0D]  
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/* ;;N9>M?b  
**Utility.java OpYY{f  
*/ I9hK}
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package NetFox; g7W"  
|8tilOqI  
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public class Utility { j#q-^
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public Utility() q5)O%l!  
{ fmDCPkj  
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} N5b!.B x-w  
._{H~R|  
//线程睡眠 5C5sgR C  
public static void sleep(int nSecond) b}TS0+TF  
{ JrRH\+4K  
try{ -C?ZB}`   
Thread.sleep(nSecond); P me^l%M  
} |4 0`B% Z  
catch(Exception e) ,wAF:7'  
{ :^B1~p(?sK  
e.printStackTrace (); E#N|wq  
} I(BQ34q  
} YGCL2Y  
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//日志 l)l^[2  
public static void log(String sMsg) _.Uh)-yR  
{ %aVq+kC h  
System.err.println(sMsg); x-&@wMqkc  
} 'kO!^6=4M  
lp%pbx43s  
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public static void log(int sMsg) H]Z$OpI  
{ tG22#F`  
System.err.println(sMsg); [%1CRk  
} 57']#j#"hj  
} ;,:`1UI  
+*/Zu`kzX  
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/* Od,qbU4O  
**TestMethod.java fSvM(3Y<Qh  
*/ :(*V?WI  
package NetFox; [~c|mOk  
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XYOC_.f1  
public class TestMethod { VY=jc~c]v  
h^(*Tv-!  
dn$!&
  
public TestMethod() z/2//mM  
{ ///xx/weblogic60b2_win.exe DAr1C+Dy  
try{ '$]97b7G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }Sh?S]]`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;RPx^X~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8\A#CQ5b  
fileFetch.start(); ^KT Y?  
} scz&h#0V  
catch(Exception e){e.printStackTrace ();} [MM~H0=s  
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7CURhDdk  
} m'=Crei  
uGK.\PB$  
a![{M<Y~  
public static void main(String[] args) ,G?WAOy,  
{ h_,i&d@(  
new TestMethod(); j@3Q;F0ba  
} q\4Xs$APq  
} 9W1YW9rL  
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