http断点续传简单实现（java)

/* ^Y{6;FJ  
**SiteFileFetch.java ]g>m?\'n  
*/ <+T\F;   
package NetFox; *K+jsVDY  
import java.io.*; ]_ejDN\>{V  
import java.net.*; cuQ7kECV  
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public class SiteFileFetch extends Thread { FQk_#BkK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s;B j7]  
long[] nStartPos; //开始位置 ?qg^WDs$  
long[] nEndPos; //结束位置 bkr~13S{+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qGpP,  
long nFileLength; //文件长度 I|g@
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boolean bFirst = true; //是否第一次取文件 lh,ylh  
boolean bStop = false; //停止标志 ?iPZsV  
File tmpFile; //文件下载的临时信息 A6^p}_  
DataOutputStream output; //输出到文件的输出流 E!zd(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |rE!   
public SiteFileFetch(SiteInfoBean bean) throws IOException 5q5 )uv"  
{ Q7~'![(a  
siteInfoBean = bean; @<D'-mMt  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tt6. jo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @-wNr
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if(tmpFile.exists ()) ;x:k-s2-  
{ 6R1wn&8  
bFirst = false; ku/\16E/k  
read_nPos(); (dzH3_U  
} BIxV|\k  
else h8f!<:rTS  
{ '1W!xQ}E  
nStartPos = new long[bean.getNSplitter()]; r{t.c?/  
nEndPos = new long[bean.getNSplitter()]; MV"E?}0  
} P0%N Q1bn  
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} 5h`m]#YEG  
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public void run() |av*!i5Q  
{
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//获得文件长度 2[jL^XMM  
//分割文件 Jj2g5={  
//实例FileSplitterFetch 2y3?!
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//启动FileSplitterFetch线程 O&`U5w  
//等待子线程返回 x96qd%l/  
try{ f
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if(bFirst) +7| [b  
{ /xl4ohL$a  
nFileLength = getFileSize(); .)LZ`Ge3F  
if(nFileLength == -1) Mw/?wtW  
{ vuYO\u+ud  
System.err.println("File Length is not known!"); }1QI"M*  
} J.1O/Pw!.a  
else if(nFileLength == -2) S5uJX#*;  
{ H_VEPp,T  
System.err.println("File is not access!"); rHvF%o  
} x&at^Fp  
else CQ@LmTW[  
{ /8f>':zUb  
for(int i=0;i<nStartPos.length;i++) an3~'g?  
{ AXz-4,=xX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u@<Pu@?xm  
} :lUX5j3  
for(int i=0;i<nEndPos.length-1;i++) 1TKEm9j]u  
{ [/ AIKZM<  
nEndPos = nStartPos[i+1]; I[}75:^Rt  
} ?q\FLb%"7  
nEndPos[nEndPos.length-1] = nFileLength; ;avQ1T'{?g  
} 3\;v5D:  
} d)N^PJ/  
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//启动子线程 ,mBZ`X@N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =v.{JV#  
for(int i=0;i<nStartPos.length;i++) DW#
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{ 3)}(M
 
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W%TQYR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +wipfL~&S  
nStartPos,nEndPos,i); w#oGX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :*^:T_U  
fileSplitterFetch.start(); <>%,}j 9  
} M(yH%i^A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rVY?6OMkd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y<TOqn  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )IQ*  
nEndPos = " + nFileLength); X:>$8^gS  
// fileSplitterFetch[nPos.length-1].start(); `)T&~2n
 
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//等待子线程结束 Bp :~bHf  
//int count = 0; =-_)$GOI'  
//是否结束while循环 g6WPPpqus  
boolean breakWhile = false; X2qv^G,  

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t#Th9G]1  
while(!bStop) te i`/  
{ Bz?l{4".  
write_nPos(); c7\VTYT  
Utility.sleep(500); zxkM'8JC  
breakWhile = true; +=7:4LFOL  
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for(int i=0;i<nStartPos.length;i++) -;$nb~y  
{ a5|@R<iF  
if(!fileSplitterFetch.bDownOver) NetYg]8`  
{ ^5>s7SGB"  
breakWhile = false; 3)3Hck  
break; @D)Z{=>{=5  
} L7]]ZAH!1  
} {Bh("wg$Lk  
if(breakWhile) Ea-bC:>  
break; !DPF7x(-{  
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K/^ +eoW(  
//count++; WfZF~$li`  
//if(count>4) OiF{3ae(  
// siteStop(); i\)3l%AK]T  
} =Q-k'=6\  
);Z]SGd  
2:Q(Gl`<l  
System.err.println("文件下载结束！"); ;\qXbL7  
} P>(P2~$Y"  
catch(Exception e){e.printStackTrace ();} qNxB{0(D  
} VevNG*  
Fi4UaJ3K  
-p`L%xj\  
//获得文件长度 4J5pXlzV  
public long getFileSize() FbAW_Am(  
{ <C'Z H'p  
int nFileLength = -1; OUI6 ax\[  
try{ g
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URL url = new URL(siteInfoBean.getSSiteURL()); 9#qeFBI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "k:=Y7Dx  
httpConnection.setRequestProperty("User-Agent","NetFox"); F)SPaC4  
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int responseCode=httpConnection.getResponseCode(); )o{aeV  
if(responseCode>=400) m2xBS!fm  
{ &$=!dA  
processErrorCode(responseCode); Ja|{1&J.  
return -2; //-2 represent access is error px=]bALU  
} 2/B)O)#ls  
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String sHeader; 9 |{%i$  
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for(int i=1;;i++) $ J1f.YE  
{ -:<lkq&/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [|RjHGf  
//Utility.log(in.readLine()); | kXm}K  
sHeader=httpConnection.getHeaderFieldKey(i); };b1ahaG  
if(sHeader!=null) iidT~l  
{ /7/0x ./{  
if(sHeader.equals("Content-Length")) 6ZOy&fd,Ty  
{ 1$pb (OK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XN;&qR^j  
break; gl8Ib<{  
} Q`ME@vz  
} Vn, ><g  
else q/PNJ#<  
break; QA?oJ_}y  
} fDh]tua  
} eKG2*CV  
catch(IOException e){e.printStackTrace ();} /Vww?9U;  
catch(Exception e){e.printStackTrace ();} =:=/Gz1  
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d ~`V7B2Y  
Utility.log(nFileLength); w5,Mb  
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return nFileLength; W\cjdd  
} wRvb8F0  
)d`mvZBn1  
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//保存下载信息（文件指针位置） Ak@Dyi?p  
private void write_nPos() 86 .`T l;  
{ r.yK,  
try{ YcDe@Zuwn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w0lT%CPx  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) =qu(~]2(  
{ w7TJv4_  
// output.writeLong(nPos); $B(kZ  
output.writeLong(fileSplitterFetch.nStartPos); r!GW=u'  
output.writeLong(fileSplitterFetch.nEndPos); 8b(!k FxD  
} -_N)E ))G  
output.close(); ;9a 6pz<  
} `]i []|  
catch(IOException e){e.printStackTrace ();} %*}Y6tl'|  
catch(Exception e){e.printStackTrace ();} "ju'UOcS/  
} iE].&>w  
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//读取保存的下载信息（文件指针位置） G`0
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private void read_nPos() zM#sOg  
{ 8LzBh_J?  
try{ u<xo/=Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !l@zT}i??  
int nCount = input.readInt(); P-`(0M7^  
nStartPos = new long[nCount]; 9+=gke  
nEndPos = new long[nCount]; u]*0;-tz  
for(int i=0;i<nStartPos.length;i++) % Zjdl  
{ u=x+J=AH  
nStartPos = input.readLong(); d+eZub94U  
nEndPos = input.readLong(); }UwO<#  
} dT|vYK}\  
input.close(); sD;M!K_  
} hX:"QXx  
catch(IOException e){e.printStackTrace ();} \ 0W!4
D  
catch(Exception e){e.printStackTrace ();} zUJZ`seF  
} c9"r6j2m5  
;&b.T}Nf06  
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private void processErrorCode(int nErrorCode) C1kYl0zR[  
{ ]=pR  
System.err.println("Error Code : " + nErrorCode); /YAJbr  
} u\yVR$pQ  
w;6bD'.>;  
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//停止文件下载 zi9[)YqxPH  
public void siteStop() g4p  
{ RE2&mYt  
bStop = true; 6w8">~)Z  
for(int i=0;i<nStartPos.length;i++) e'%v1-&sP  
fileSplitterFetch.splitterStop(); "qz3u`[o  
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} Zdc63fllM  
} Mj#-j/{x{5  
//负责部分文件的抓取 &#`l;n:]+  
**FileSplitterFetch.java XRx+Dddt;  
*/ T;TA7{B  
package NetFox; b?X.U}62_  
l e4?jQQ@L  
#DU26nCL  
import java.io.*; TfYVw~p_%  
import java.net.*; soA|wk\A  
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public class FileSplitterFetch extends Thread { [epi#]m  
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String sURL; //File URL P262Q&.}d  
long nStartPos; //File Snippet Start Position H,fZ!8(A_)  
long nEndPos; //File Snippet End Position v{zMO:3  
int nThreadID; //Thread's ID }/tf>?c  
boolean bDownOver = false; //Downing is over X|f7K  
boolean bStop = false; //Stop identical ]V l]XT$Um  
FileAccessI fileAccessI = null; //File Access interface e
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gxz-R?.  
{ m7a#qs;,  
this.sURL = sURL; h,aAw#NE*  
this.nStartPos = nStart; ryF7  
this.nEndPos = nEnd; O/AaYA&  
nThreadID = id; xsd_Uu*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (wDm*bZ*  
} g
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public void run() <h%O?mkC  
{ An;MVA  
while(nStartPos < nEndPos && !bStop) 5pr"d@.  
{ +/,icA}PI  
@SZM82qU2z  
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try{ EVp,Q"V]  
URL url = new URL(sURL); 3bk|<7tl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )[0T16  
httpConnection.setRequestProperty("User-Agent","NetFox"); f` =CpO*  
String sProperty = "bytes="+nStartPos+"-"; _XJ2fA )  
httpConnection.setRequestProperty("RANGE",sProperty); jK \T|vGJa  
Utility.log(sProperty); x~xa6  
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InputStream input = httpConnection.getInputStream(); m'
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//logResponseHead(httpConnection); J)P$2#  
JJ;[,  
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byte[] b = new byte[1024]; rSXh;\MfB4  
int nRead; I}Nd$P)>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _ZY)M  
{ HGm 3+,  
nStartPos += fileAccessI.write(b,0,nRead); 9Gv[8'I  
//if(nThreadID == 1) 'YNT8w/3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =]:>"_jN  
} GKN%Tv:D_  
!vG'J\*xc  
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Utility.log("Thread " + nThreadID + " is over!"); 'cY`
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bDownOver = true; Y3Vlp/"rB"  
//nPos = fileAccessI.write (b,0,nRead); $)
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} #fT*]NN  
catch(Exception e){e.printStackTrace ();} m[j70jYe  
} nX$XL=6mJ&  
} J[f;Xlh  
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626Z5Afg  
//打印回应的头信息 FQ g~l4WX  
public void logResponseHead(HttpURLConnection con) O_Oj|'bBC  
{ Cvn#=6V3  
for(int i=1;;i++) nstUMr6  
{ yAoe51h?  
String header=con.getHeaderFieldKey(i); LpR3BP@At  
if(header!=null) | WvUq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w)Covz'uf  
Utility.log(header+" : "+con.getHeaderField(header)); @V03a )6,h  
else =[F<7pvE  
break; ]`Oo%$Ue  
} ,o)d3g-&g  
} %-d
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public void splitterStop() g!-,]  
{ 4;2< ^[M  
bStop = true; o6V}$wT3J  
} H^YSJ6  
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} $@UN4B?y  
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/* d/i`l*  
**FileAccess.java AhZ8 0!  
*//文件访问(定位，写) N!g9*Z
 
package NetFox; tKpmm`2  
import java.io.*; 9<KAXr#  
1Tu *79A  
qi_Jywd:w  
public class FileAccessI implements Serializable{ _-EyT  
r#XT3qp$d  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @|\}.M<e*)  
RandomAccessFile oSavedFile; =jN*P?  
long nPos; mauI42  
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public FileAccessI() throws IOException ih7/}  
{ XGl+S  
this("",0); mvq&Pj 1}L  
} g1jTy7g?  
~Q\3pI. |  
7D<#(CE{  
public FileAccessI(String sName,long nPos) throws IOException ]MxC_V+P`  
{ 3`k;a1Z#O'  
oSavedFile = new RandomAccessFile(sName,"rw"); {~F4WjHJp  
this.nPos = nPos; B[KJR?>  
oSavedFile.seek(nPos); aoXb22]{  
} zzxGAVu  
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}`@728E  
public synchronized int write(byte[] b,int nStart,int nLen) E2m8UBS  
{ h=:Q-?n-  
int n = -1; VY3&  
try{ w
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oSavedFile.write(b,nStart,nLen); ~J P=T  
n = nLen; }2e??3  
} ho$+L  
catch(IOException e) bua+I;b  
{
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e.printStackTrace (); ]wtb-PC  
} QDu2?EYZq  
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return n; g[3)P+  
} `DC2gJKk%  
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} ={z*akn,  
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/* PbmDNKEh{  
**SiteInfoBean.java S;)w.  
*/ 6Aku1h  
package NetFox; tQjLOv+?=  
@~%r5pz6  
kOed ]>H  
public class SiteInfoBean { {j7uv"|X7  
^pYxKU_O  
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private String sSiteURL; //Site's URL `5C,N!d8X  
private String sFilePath; //Saved File's Path og kD^   
private String sFileName; //Saved File's Name dUQDOo  
private int nSplitter; //Count of Splited Downloading File t{.8|d@  
H XmS|PX  
FAj)OTI2S  
public SiteInfoBean() +1D+]*t_?[  
{//nSplitter的缺省值为5 #H:7@  
//default value of nSplitter is 5 lMBLIB
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this("","","",5); ^3UGV*Ypk  
} sNLs\4v  
1A\OC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MerFZd 1  
{ @WVcY:1t#  
sSiteURL= sURL; 6=fSE=]DY  
sFilePath = sPath; EUxGAj$-  
sFileName = sName; @g&ct>@y  
this.nSplitter = nSpiltter; 8/=L2fNN[  
&MCbYph,  
#':fkIYe'  
} BYMi6wts  
o<|P9#(U"  
}3OKC2K~  
public String getSSiteURL() MZT23[+  
{ 6Q${U7%7  
return sSiteURL; y$_eCmq  
} "\3B^ e,  
"t~  
E/%9jDTQ  
public void setSSiteURL(String value) H
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{ Y9&,t\ q  
sSiteURL = value; rl#p".4q  
} o !vE~  
iT%} $Lu~  
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public String getSFilePath() PEc=\?  
{ ZR(x%ews  
return sFilePath; Yj6*NZ*  
} njWL U!  
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public void setSFilePath(String value) 23DiW#o'  
{ (aH'h1,G  
sFilePath = value; 9R7A8  
} z}MP)|aH:  
/,g,Ch<d  
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public String getSFileName() pLLGus+W  
{ Bi @2  
return sFileName; @ < Q|5  
} n6BQk2l  
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public void setSFileName(String value) a_'2V;  
{ //s:5S<Z  
sFileName = value;
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} ''0fF_P  
W7 #9jo  
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public int getNSplitter() =g|IG [V  
{ n}!PO[m~  
return nSplitter; !& z(:d  
} .MP !`  
O vk_\On  
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public void setNSplitter(int nCount) xUa{1!Y8  
{ YLiSbLz1  
nSplitter = nCount; _s .G  
} 4UW_Do  
}  q)^Jj?W  
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VB,?Mo}R  
/* z<##g  
**Utility.java mjKS{  
*/ Yd#/1!A7u  
package NetFox; {l
/-LZ.  
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public class Utility { <U!`J[n%  
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public Utility() WRrd'{sB  
{ vJ-q*qM1  

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} 29?,<bB)  
3tZ]4ms}  
//线程睡眠 L_wk~z  
public static void sleep(int nSecond) nh!a)]c[  
{ '8{Ne!y  
try{ -\ EP.Vtz  
Thread.sleep(nSecond); DUC#NZgw  
} !>zo_fP  
catch(Exception e) 4'!c*@Y  
{ 
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e.printStackTrace (); Os
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} JU^ly
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} ]Zyur`  
dAkgR~  
//日志 RIY,K*f.  
public static void log(String sMsg) enSXP~9w  
{ Z(ACc9k6:'  
System.err.println(sMsg); zhpt%7So  
} Cif>7]M  
o .qf _A  
oBzfbg8p  
public static void log(int sMsg) H\:lxR^  
{ |Y[wzDYV  
System.err.println(sMsg); d+Ek%_  
} T^~5n6  
} JAQb{KefdO  
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/* p4-o/8rO  
**TestMethod.java ]jmL]Ny^  
*/ 5`gQ~  
package NetFox; e0T34x'
  
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ysQ,)QoiR{  
public class TestMethod { RWgNo#<  
JQ6zVS2SSS  
)`A3M)  
public TestMethod() :=/>Vbd: )  
{ ///xx/weblogic60b2_win.exe T QSzx%i2  
try{ [ji#U s:h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C86J IC"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i5K[>5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F=a
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fileFetch.start(); 1M 781  
} ZGYr$C~  
catch(Exception e){e.printStackTrace ();} O2f-5Y$@  
),ma_{$N  
,kF}lo)  
} 1][S#H/?  
Gr^E+#;  
hnc@  
public static void main(String[] args) -2A(5B9Fq  
{ _;UE9S%  
new TestMethod(); \3S8 62B7  
}  lS'-xEv?  
} al9t^  
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