http断点续传简单实现（java)

/* +V046goX W  
**SiteFileFetch.java }"%?et(  
*/ NzOx0WLF  
package NetFox; W^LY'ypT  
import java.io.*; c"V"zg22  
import java.net.*; Ep3N&Imp  
k(7&N0V%zz  
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public class SiteFileFetch extends Thread { jrr*!^4|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^{;oM^Q'  
long[] nStartPos; //开始位置 ][h%UrV  
long[] nEndPos; //结束位置 Yz"#^j}Kg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jaMjZp;{(  
long nFileLength; //文件长度 aPfO$b:  
boolean bFirst = true; //是否第一次取文件 J1RJ*mo7,  
boolean bStop = false; //停止标志 GmEJhr.3`=  
File tmpFile; //文件下载的临时信息 cyv`B3}  
DataOutputStream output; //输出到文件的输出流 JZ*/,|1}EC  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MvHm)h  
public SiteFileFetch(SiteInfoBean bean) throws IOException j94=hJVKi  
{ BBRR
)  
siteInfoBean = bean; KNpl:g3{<Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #;qdY[v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lN?qp'%H`  
if(tmpFile.exists ()) lC("y' ::  
{ #+HJA42  
bFirst = false; `nv~NLkl  
read_nPos(); "
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} ex9g?*Q  
else #9}D4i.`}  
{ D] jzAx  
nStartPos = new long[bean.getNSplitter()]; lVR~Bh  
nEndPos = new long[bean.getNSplitter()]; T?soJ]A  
} E=CsIK   
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} m=A(NKZ  
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public void run() ;F!5%}OcL%  
{ iWB=sL&p  
//获得文件长度 aS{n8P6vW  
//分割文件 z/WE,R  
//实例FileSplitterFetch [.'|_l  
//启动FileSplitterFetch线程 <+Dn8  
//等待子线程返回 3<Zq ]jk?n  
try{ bv9i*]  
if(bFirst) gG:Vt}N  
{ EQyC1j  
nFileLength = getFileSize(); LX
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if(nFileLength == -1) '4Ixqb+  
{ 4Lh!8g=/  
System.err.println("File Length is not known!"); [.8BTj1%  
} %C'?@,7C  
else if(nFileLength == -2) &Gn 2tr  
{ W5lR0)~#*  
System.err.println("File is not access!"); H*QIB_  
} #!qm ZN  
else c~$)UND^  
{ Y1OkkcPb{  
for(int i=0;i<nStartPos.length;i++) @+
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{ KL:j
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); X_ cV%#  
} {M$1N5Eh  
for(int i=0;i<nEndPos.length-1;i++) 3yY}04[9<  
{ (GuzN  
nEndPos = nStartPos[i+1]; nntuLuW  
} 2*< nu><b  
nEndPos[nEndPos.length-1] = nFileLength; w%VU/6
~  
} HU}7zK2  
} C:* *;=.  
,p@y] cr  
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//启动子线程 `*["UER  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k\YG^I  
for(int i=0;i<nStartPos.length;i++) a|x.C6Pe  
{ axRV:w;E<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [b<oDX#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |zNX=mAV  
nStartPos,nEndPos,i); _AYK435>N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o\<ULW*  
fileSplitterFetch.start(); *@r/5pM2}  
} 69?wc!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Un(aW=PQ0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M~#gRAUJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Xe'x[(l  
nEndPos = " + nFileLength); bv9]\qC]T<  
// fileSplitterFetch[nPos.length-1].start(); p2[n$61  
_476pZ_  
N/'b$m5= S  
//等待子线程结束 >~sI8czR*  
//int count = 0; -M~:lK]n  
//是否结束while循环 dulI&_x  
boolean breakWhile = false; GR.^glG?6  
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while(!bStop) Y3cMC)  
{ qu6D 5t  
write_nPos(); D|L9Vs`  
Utility.sleep(500); '!cCMTj  
breakWhile = true; (KD RkE|=  
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for(int i=0;i<nStartPos.length;i++) HTcb_a  
{ 2K6qY)/_  
if(!fileSplitterFetch.bDownOver) #7$ H  
{ /-qNh>v4  
breakWhile = false; :&rt)/I  
break; k&q;JyUi  
} <QAFL uey  
} V-2(?auZd  
if(breakWhile) v0+BkfU+p  
break; 4qh?,^Dq  
\0I_<  
#n#}s  
//count++; VUGmi]qd  
//if(count>4) I-)+bV G  
// siteStop(); 4Zddw0|2  
} m@F`!qY~Y\  
~&_z2|UXp  
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System.err.println("文件下载结束！"); d-ZJL6-  
} @|m/djN5x  
catch(Exception e){e.printStackTrace ();} oUr66a/[U  
} 9@:2wR |  
Jk11fn;\>  
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//获得文件长度 m%?pf2%I#  
public long getFileSize() xY8$I6  
{ t]g-CW3  
int nFileLength = -1; o5O#vW2Il&  
try{ (k)v!O-  
URL url = new URL(siteInfoBean.getSSiteURL()); ww3-^v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z`}qkbvi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1;8UC;,  
2'\H\|  
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int responseCode=httpConnection.getResponseCode(); $am$EU?s  
if(responseCode>=400) t!X.|`h  
{ :zbQD8jv  
processErrorCode(responseCode); Hqx-~hQO  
return -2; //-2 represent access is error KYhwOGN  
} b<ZIWfs  

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String sHeader; "ycJ:Xv49  
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6=/F$|  
for(int i=1;;i++) A#<?4&  
{ -p-ZzgQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cn3\k
T*  
//Utility.log(in.readLine()); 'n]w"]|  
sHeader=httpConnection.getHeaderFieldKey(i); jo@6?( *4  
if(sHeader!=null) F6|]4H.3Q  
{ 1D7`YKI9h  
if(sHeader.equals("Content-Length")) [Ek7b*  
{ o5GcpbZ3k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (@VMH !3  
break; LEf^cM=>  
} D%SlAzZ3  
} X-Kh(Z  
else T!kN)#S  
break; n\'4  
} 1#2 I  
} MUc$j&  
catch(IOException e){e.printStackTrace ();} @ioJ]$o7  
catch(Exception e){e.printStackTrace ();} [5b--O  
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Utility.log(nFileLength); k5e;fA/w  
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return nFileLength; #x60xz  
} 9T9!kb  
_Y4` xv0/  
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//保存下载信息（文件指针位置） =v&hWjP  
private void write_nPos() >Q;l(fdj  
{ n'LrQU  
try{ [yQt^!;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _8J.fT$${  
output.writeInt(nStartPos.length); sb*G!8j  
for(int i=0;i<nStartPos.length;i++) $GcqBg-Hi  
{ ]p GL`ge5  
// output.writeLong(nPos); q`7PhA
  
output.writeLong(fileSplitterFetch.nStartPos); :\c ^*K(9  
output.writeLong(fileSplitterFetch.nEndPos); m?}6)\ob  
} p27~>xQ  
output.close(); P|E| $)m  
} rJ4S%6w  
catch(IOException e){e.printStackTrace ();} FVbb2Y?R  
catch(Exception e){e.printStackTrace ();} f~R(D0@  
} R+z2}}Z!`  
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//读取保存的下载信息（文件指针位置） [l??A
3G  
private void read_nPos() ?e4YGOe.  
{ t%)7t9j  
try{ @b%=H/5\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k]|~>9eY]  
int nCount = input.readInt(); +@f26O7$*  
nStartPos = new long[nCount]; lfgq=8d  
nEndPos = new long[nCount]; Qd{CMmx  
for(int i=0;i<nStartPos.length;i++) ;ef}}K  
{ lrE5^;/s1  
nStartPos = input.readLong(); ? :%@vM  
nEndPos = input.readLong(); ec;o\erPG  
} I$G['`XX/  
input.close(); gz9j&W.  
} JPHL#sKyz  
catch(IOException e){e.printStackTrace ();} z&\a:fJ&  
catch(Exception e){e.printStackTrace ();} J*A,o~U|  
} |YWD8 +  
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private void processErrorCode(int nErrorCode) VCkq"f7cw  
{ n( yn<  
System.err.println("Error Code : " + nErrorCode); Ll't>)  
} N>`Aw^ _@&  
+Kc
  
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//停止文件下载 nR~@#P\  
public void siteStop() T?
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{ (5YM?QAd  
bStop = true; vA{-{Q  
for(int i=0;i<nStartPos.length;i++) (%6P0*  
fileSplitterFetch.splitterStop(); Nai2W<,  
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} ;[DU%f  
} zC!t;*8a  
//负责部分文件的抓取 $h"\N$iSq  
**FileSplitterFetch.java 9cF[seE"0  
*/ 8TKnL\aar  
package NetFox; >tr}|>  
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import java.io.*; h438`  
import java.net.*;  mq.`X:e  
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public class FileSplitterFetch extends Thread { {JT&w6Jz  
+O{*M9B  
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String sURL; //File URL 6nvz8f3*r]  
long nStartPos; //File Snippet Start Position Yj49
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long nEndPos; //File Snippet End Position qyTU8Wp  
int nThreadID; //Thread's ID cm+Es6
;  
boolean bDownOver = false; //Downing is over g!|kp?  
boolean bStop = false; //Stop identical :5<UkN)R(  
FileAccessI fileAccessI = null; //File Access interface #;yZ  
#;e:A8IQ  
6bC3O4Rw  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x 9fip-  
{  }my`K  
this.sURL = sURL; -Q*gW2KmV  
this.nStartPos = nStart; 5t]H?b8  
this.nEndPos = nEnd; a1lh-2xX  
nThreadID = id; q0vQa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,f>k%_U}  
} Y:[u1~a  
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public void run() #X1
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{ :"c*s4  
while(nStartPos < nEndPos && !bStop) TvbE2Q;/UL  
{ DvvK^+-~  
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try{ f+!(k)GWd  
URL url = new URL(sURL); k9!{IScq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F JyT+  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dp9+HA9
t  
String sProperty = "bytes="+nStartPos+"-"; (!WD1w
 
httpConnection.setRequestProperty("RANGE",sProperty); nNn:-  
Utility.log(sProperty); :vbW  
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InputStream input = httpConnection.getInputStream(); 6i/(5 nQ  
//logResponseHead(httpConnection); b]KBgZ  
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byte[] b = new byte[1024]; z2GY:<s  
int nRead; =Xr.'(U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1yhD
rpm  
{ Dlvz)  
nStartPos += fileAccessI.write(b,0,nRead); s$j,9uRr  
//if(nThreadID == 1) InI$:kJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ww1[rCh\+  
} ]/L0,^RI  
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Utility.log("Thread " + nThreadID + " is over!"); D&y7-/  
bDownOver = true; K
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//nPos = fileAccessI.write (b,0,nRead); WpvhTX  
} %pCT
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catch(Exception e){e.printStackTrace ();} es7=%!0  
} &oMh]Z*:  
} "w<#^d_6  
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//打印回应的头信息 ~P-mC@C  
public void logResponseHead(HttpURLConnection con) w7L)'9  
{ 4Z0]oIX  
for(int i=1;;i++) G3T]`Atf  
{ -QNh  
String header=con.getHeaderFieldKey(i); ~k5W@`"W  
if(header!=null) z F;K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;O,jUiQ  
Utility.log(header+" : "+con.getHeaderField(header)); hhvyf^o  
else 4*;MJ[|  
break; %?/
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} dWBA1p  
} JucY[`|JV  
y@yD5$/  
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public void splitterStop() \9EjClfo  
{ E]r?{t`]  
bStop = true; owv[M6lbD  
} H\[W/"  
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} R4d=S4i  
a 1*p*dM#  
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/* "0TZTa1e  
**FileAccess.java
Iq.*8Oc  
*//文件访问(定位，写) tZo} ;|~'  
package NetFox; u ^RxD^=L  
import java.io.*; zm;C\s rF  
GC'O[q+  
/>>\IR  
public class FileAccessI implements Serializable{ |y!A&d=xYn  
,/unhfs1q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DtnEi4h,  
RandomAccessFile oSavedFile; ],].zlN  
long nPos; EoDA]6?Lj  
-UT}/:a  
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public FileAccessI() throws IOException sDV Q#}a  
{ g9F?z2^  
this("",0); poFg1  
} i@J;G`  
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public FileAccessI(String sName,long nPos) throws IOException |EN
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{ Xn ;AZu^'R  
oSavedFile = new RandomAccessFile(sName,"rw"); A+{VGP^  
this.nPos = nPos; (7*}-Uy[C  
oSavedFile.seek(nPos); 6W UrQFK  
} Gs[XJ 5%`~  
@KAI4LP  
#.[k=dj   
public synchronized int write(byte[] b,int nStart,int nLen) 3;Fhg!ZO  
{ :BTq!>s  
int n = -1; syK^<xa  
try{ TS5Q1+hWHV  
oSavedFile.write(b,nStart,nLen); @lph)A Nk  
n = nLen; k VQ\1!  
} Aiea\jBv  
catch(IOException e) Wm5dk9&x  
{ {l>hMxij  
e.printStackTrace (); +nGAz{&@r%  
} Y6d@h? ht  
qIqM{#' ^  
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return n; lw5`p,`  
} n'w.; q  
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} g=o4Q< #^y  
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/* |zE'd!7E  
**SiteInfoBean.java h)nG)|c  
*/ " 2Dngw  
package NetFox; FxtI"g\0  
POR\e|hRT]  
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public class SiteInfoBean { !{41!O,K#  

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}o{
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private String sSiteURL; //Site's URL c[Zje7 @  
private String sFilePath; //Saved File's Path %u5]>]M+  
private String sFileName; //Saved File's Name Om {'1  
private int nSplitter; //Count of Splited Downloading File dC4'{n|7  
y*h<MQ  
>yh2Lri  
public SiteInfoBean() &iVs0R  
{//nSplitter的缺省值为5 \D&KC,i5f  
//default value of nSplitter is 5 /H+a0`/  
this("","","",5); 7v_8_K  
} M& CqSd  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 76` .Y  
{ ,,|^%Ct']  
sSiteURL= sURL; 5rUdv}.  
sFilePath = sPath; .3!1`L3  
sFileName = sName; @ur+;IK$  
this.nSplitter = nSpiltter; T9q-,w/j;  
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W`*r>`krVJ  
} &]-DqK7  
*4_Bd=5(U  
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public String getSSiteURL() ?[>3QE  
{ 9Lfv^V0  
return sSiteURL; 5ms(Wd  
} G9vpt M  
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*k>n<p3dd  
public void setSSiteURL(String value) Q)z8PQl O  
{ sFTy(A/  
sSiteURL = value; ji,kkipY?w  
} RY*U"G0#w  
qb` \)X]9  

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public String getSFilePath() VgS_s k  
{ rk)`\=No  
return sFilePath; dcWD(-  
} jm r"D>  
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m9}P9?  
public void setSFilePath(String value) w.-!UD9/.x  
{ *G9V'9  
sFilePath = value; k+l b@!  
} 9k[9P;"F:  
:S(ZzY Q  
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public String getSFileName() ?#Q #u|~  
{ F^fdIZx  
return sFileName; 2T[9f;jM'  
} $a ` G  
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'(jG[ry&T  
public void setSFileName(String value) Lbb0_-']  
{ QnX(V[  
sFileName = value; %C_HXr@  
} ',5ky{  
^D-/`d  
j^2j&Ta  
public int getNSplitter() KdbHyg<4  
{ 42ivT_H  
return nSplitter; 3%=~)7cF  
} %3''}Y5  
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}|5Pr(I  
public void setNSplitter(int nCount) ^@NU}S):yN  
{ ,UdVNA  
nSplitter = nCount; Bj-:#P@  
} @x'"~"%7b  
} ^mO~W!"  
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/* E3gh?6  
**Utility.java .Blf5b  
*/ WE.{p>  
package NetFox; -^h' >.  
};jN\x?&q  
#S*/bao#  
public class Utility { 8sM|%<$=j  
dS!:JO27  
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public Utility() 4Vi`* !  
{ 4DOH`6#an  
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~8P!XAU56%  
} {rH@gz|@i  
';jYO
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//线程睡眠 O%
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public static void sleep(int nSecond) RcM/!,B  
{ EGzzHIZ`!  
try{ ^l=!JP=M=  
Thread.sleep(nSecond); >dG;w
6y'  
} h WtVWVNL  
catch(Exception e) B!_mC<*4`X  
{ pg.ri64H<  
e.printStackTrace (); A1D^a,  
} 4Thn])%I  
} 9~mh@Kgv  
:'3XAntZA  
//日志 IE&!YP(U(  
public static void log(String sMsg) Dhw(#{N  
{ ?Exv|e  
System.err.println(sMsg); dzsmIV+  
} 'y2nN=CN  
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public static void log(int sMsg) D2!X?"[P  
{ QnXA*6DJ  
System.err.println(sMsg); 7;sj%U^'l  
} bRJMYs  
} 1+qw$T  
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/* ?NR A:t(}  
**TestMethod.java )- viGxJ@  
*/ 36
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package NetFox; xtE_=
5$~  
!?
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!*m5F8Qm?A  
public class TestMethod { LuSLkLN  
%Bn?n{/  
V
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public TestMethod() ') gi%  
{ ///xx/weblogic60b2_win.exe o/6-3QUak  
try{ XKttZOiGT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i;jw\ed  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Rhz_t@e  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r>"   
fileFetch.start(); 7_Z#m (  
} F\AX:  
catch(Exception e){e.printStackTrace ();} 04'~ta(t  
'wI"Bo6e  
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} Q/I!}C4  
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x&9hI  
public static void main(String[] args) y[\VUzD*'  
{ m&\h4$[kql  
new TestMethod(); l>{R`BZ/  
} +~roU{& o  
} ?~;:jz|9<'  
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