http断点续传简单实现（java)

/* Fl&Z}&5p  
**SiteFileFetch.java l:rT{l=8*  
*/ \LZVazXD  
package NetFox; - d(RK_  
import java.io.*; SRf.8j  
import java.net.*; G%RhNwm  
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public class SiteFileFetch extends Thread { _f5n t:-  
8]-c4zK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b".e6zev  
long[] nStartPos; //开始位置 `jyBF  
long[] nEndPos; //结束位置 "
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 -THU5AB  
long nFileLength; //文件长度 F
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boolean bFirst = true; //是否第一次取文件 }c~o3t(7`b  
boolean bStop = false; //停止标志 b];? tP  
File tmpFile; //文件下载的临时信息 "G3zl{?GP  
DataOutputStream output; //输出到文件的输出流 B'"RKs]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8h| 9;%  
public SiteFileFetch(SiteInfoBean bean) throws IOException O'} %Bjl  
{ C7lBK<gQ  
siteInfoBean = bean; %1oG<s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $9Yk]~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 17{$D,P  
if(tmpFile.exists ()) 4(FEfde=  
{ jvfQG:F }  
bFirst = false; QL4BD93v  
read_nPos(); #b?)fqRJL  
} jsrIZbN  
else RY]Vo8  
{ ;_vo2zl1  
nStartPos = new long[bean.getNSplitter()]; 7v^V]&&s  
nEndPos = new long[bean.getNSplitter()]; #fR~7KR  
} XY1eeB-  
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} [nnX,;  
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public void run() 3l8k O  
{ z1u1%FwOfM  
//获得文件长度 n!K<g.tjW  
//分割文件 {v>orP?  
//实例FileSplitterFetch D7"RZF\)  
//启动FileSplitterFetch线程 Htu}M8/4  
//等待子线程返回 oTqv$IzqP  
try{ ADQ#qA,/  
if(bFirst) Q7-d]xJ^  
{ x.OCE`  
nFileLength = getFileSize(); ;=[~2*8  
if(nFileLength == -1) &:"[hU  
{ xYGB{g]  
System.err.println("File Length is not known!"); bez_|fY{T  
} $WV N4fg  
else if(nFileLength == -2) X^;LiwQv  
{ oI6l`K$  
System.err.println("File is not access!"); iHB1/  
} aA5rvP+  
else 09psqXU@I  
{ |tkhsQ-;  
for(int i=0;i<nStartPos.length;i++) *j0kb"#  
{ LYv$U;*+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sZ!/uN!6  
} CI };$4W~  
for(int i=0;i<nEndPos.length-1;i++) XvIrO]F-  
{ C/{tvY /o  
nEndPos = nStartPos[i+1]; eZ^-gk?  
} -:|1>og  
nEndPos[nEndPos.length-1] = nFileLength; {IlX@qWr  
} `1
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} z`:uvEX0  
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//启动子线程 9<ev]XaSl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rprtp5Cg  
for(int i=0;i<nStartPos.length;i++) V!Q1o!J  
{ Alsr6uLT1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -%*w&',G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0DFxVH_xN  
nStartPos,nEndPos,i); mar BVFz~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eaI!}#>R+  
fileSplitterFetch.start(); `f9I#B  
} UF)4K3X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #l!Sz247  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KF#,Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )Bq~1M 2  
nEndPos = " + nFileLength); smM*HDK  
// fileSplitterFetch[nPos.length-1].start(); C)r!;u)AZH  
w
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-m.SN>V  
//等待子线程结束 f;k'dqlv  
//int count = 0; >%~%O`+  
//是否结束while循环 A\jX#gg  
boolean breakWhile = false; RU1+-  
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while(!bStop) 1qw*mV;W)_  
{ T@ [
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write_nPos(); x-:a5Kz!  
Utility.sleep(500); Fj`6v"h  
breakWhile = true; 7n1@m_7O  
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for(int i=0;i<nStartPos.length;i++) h7( R/Rf  
{ )@ /!B`  
if(!fileSplitterFetch.bDownOver) i5>]$j1/  
{ F|3 =Cl  
breakWhile = false; U/e$.K3v  
break; 39w|2%(O.  
} ]0VjVU-  
} ?~;8Y=O  
if(breakWhile) XL/?v" /  
break; ` R;6]/I?  
/GK1}h  
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//count++; MmjeFv  
//if(count>4) RE72%w(oM  
// siteStop(); Hvn{aLa.  
} nH#|]gVI  
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4&Q.6HkL  
System.err.println("文件下载结束！"); O;u&>BMk  
} ~"E@do("  
catch(Exception e){e.printStackTrace ();} yX}riXe
  
} a]<y*N?qu  
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//获得文件长度 #)aUKFX  
public long getFileSize() iI27N'g  
{ liW0v!jBo  
int nFileLength = -1; @w)Vt$+b]  
try{ 1CkBfK  
URL url = new URL(siteInfoBean.getSSiteURL()); 0i[,`>-Av  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Qgxf';+$  
httpConnection.setRequestProperty("User-Agent","NetFox"); >Jl(9)e  
Ix;9D'^}  
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int responseCode=httpConnection.getResponseCode(); q F\a]e  
if(responseCode>=400) 7j&iHL  
{ #|\NG  
processErrorCode(responseCode); ~Bll\3-=  
return -2; //-2 represent access is error eB`7C"Z  
} K[%)_KW  
,DN>aEu1  
: GZx-   
String sHeader; ?N 6'*2{NT  
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for(int i=1;;i++) <p<J;@  
{ |fx*F}1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'n7)()"2  
//Utility.log(in.readLine()); )Q_^f'4  
sHeader=httpConnection.getHeaderFieldKey(i); +ht -Bl  
if(sHeader!=null) <<zYF.9L]  
{ KaJCfu yp  
if(sHeader.equals("Content-Length")) w`kn!k8  
{ Tl.dr   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _H:mBk,,  
break; ]UR@V;JG  
} Pg]&^d&$  
} ]ov>VF,<  
else ^:.=S`,^  
break; 35dbDgVz$  
} no*p`a *  
} :27GqY,3sK  
catch(IOException e){e.printStackTrace ();} 5",@!1ju  
catch(Exception e){e.printStackTrace ();} 8Bvc#+
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Utility.log(nFileLength); mHqw,28}  
2|xNT9RW  
rZ0+mS'/G  
return nFileLength; pDGX$1O"  
} X>Cl{.  
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vJ__jO"Sq  
//保存下载信息（文件指针位置） rkF]Q_'`t;  
private void write_nPos() _raj b1!  
{ `K.2&6xc  
try{ 0B0Uay'd_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lx8@;9fLy  
output.writeInt(nStartPos.length); B'( /W@  
for(int i=0;i<nStartPos.length;i++) O7p>"Bh  
{ p`@7hf|hm  
// output.writeLong(nPos); c#?JW:^|Df  
output.writeLong(fileSplitterFetch.nStartPos); j'#Y$d1.  
output.writeLong(fileSplitterFetch.nEndPos); LTGKs^i4  
} :zXkQQD8`  
output.close(); >wiW(Ki}  
} $F|3VQ~  
catch(IOException e){e.printStackTrace ();} teO%w9ByY  
catch(Exception e){e.printStackTrace ();} N? r{Y$x  
} c2aX_ "  
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//读取保存的下载信息（文件指针位置） Yx4TUA$c'  
private void read_nPos() oMH-mG7:K  
{ R;2tb7o  
try{ }%K)R5C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =-XI)JV#  
int nCount = input.readInt(); 3jMHe~.E<  
nStartPos = new long[nCount]; ')kn  
nEndPos = new long[nCount]; o1x IGP<  
for(int i=0;i<nStartPos.length;i++) Tw|cgB  
{ 3<ikMUq&  
nStartPos = input.readLong(); 7B@[`>5?%L  
nEndPos = input.readLong(); 1'c  
} (1`z16  
input.close(); )/BI
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} `N8?F3>
 
catch(IOException e){e.printStackTrace ();} NwH`t#zd  
catch(Exception e){e.printStackTrace ();} s8,{8k  
} YGRv``(  
D^+#RR'#,  
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private void processErrorCode(int nErrorCode) s8,N9o[.~P  
{ [42vO  
System.err.println("Error Code : " + nErrorCode); P`JO6O:&  
} ][ri A  
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a2l\B~n  
//停止文件下载 g3r4>SA  
public void siteStop() 8!a6)Zeux  
{ Q;m:o8Q5  
bStop = true; #/u%sX`#y  
for(int i=0;i<nStartPos.length;i++) 9>y6zFTV  
fileSplitterFetch.splitterStop(); ?&Zfb  
}cov"o  
}}AooziH9  
} II!Nr{A  
} >j [> 0D  
//负责部分文件的抓取 YzTmXwuA5  
**FileSplitterFetch.java F`W8\u'db  
*/ q9GSUkb  
package NetFox; "I"(yiKD  
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import java.io.*; O>YXvu  
import java.net.*; mTG v*=l  
n9.` 5BH7/  
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public class FileSplitterFetch extends Thread { ( Z-~Eh  
5r;M61  
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String sURL; //File URL i *W9 4  
long nStartPos; //File Snippet Start Position oLJP@J  
long nEndPos; //File Snippet End Position $O}:*.{(W  
int nThreadID; //Thread's ID +b<q4W  
boolean bDownOver = false; //Downing is over k
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boolean bStop = false; //Stop identical =yn|.%b  
FileAccessI fileAccessI = null; //File Access interface ,uEi*s>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dl:uI5]  
{ EeW%5/;  
this.sURL = sURL; 4%h@K(iN  
this.nStartPos = nStart; qT( 3M9!  
this.nEndPos = nEnd; }Wxu=b  
nThreadID = id; 2
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 J(CqT/Au-  
} qla$}dnvc  
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public void run() _1D'9!+  
{ p=T,JAIt  
while(nStartPos < nEndPos && !bStop) Ol8ma`}Nq3  
{ "xS?#^a  
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try{ 2Z3c`/k  
URL url = new URL(sURL); _7?LINF9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /UGH7srx  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pb05>J3N  
String sProperty = "bytes="+nStartPos+"-"; &"vh=Z-  
httpConnection.setRequestProperty("RANGE",sProperty); FKU$HQw*  
Utility.log(sProperty); ^j1?LB  
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InputStream input = httpConnection.getInputStream(); #q`-"2"|  
//logResponseHead(httpConnection); aBX^Wd  
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byte[] b = new byte[1024]; O=wA/T=w?  
int nRead; vM5u]u!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }gY:VDW  
{ !oTF2Q+C  
nStartPos += fileAccessI.write(b,0,nRead); 9p ;)s  
//if(nThreadID == 1) S^}@X?v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y|bCbaF  
} :-xF=Y(;  
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#{~  
jPG&Ypm1   
Utility.log("Thread " + nThreadID + " is over!"); Q_<CG[,6D1  
bDownOver = true; ps:|YR  
//nPos = fileAccessI.write (b,0,nRead);
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} 4%#C _pE9  
catch(Exception e){e.printStackTrace ();} :cv_G;?  
} C^]y iR-U  
} 5;=,BWU  
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?(Dk{-:
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//打印回应的头信息 RC5b'+E&#  
public void logResponseHead(HttpURLConnection con) t\2Lo7[Pu  
{ 1n7tmRl  
for(int i=1;;i++) q5il9*)d(  
{ V!=1 !"}OG  
String header=con.getHeaderFieldKey(i); AhOvI{  
if(header!=null) rSU%!E+|<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;qT~81  
Utility.log(header+" : "+con.getHeaderField(header)); KD]8n]c
 
else %a-:f)@  
break; Jq1 Zb  
} !QoOL<(){  
} k8E
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public void splitterStop() $Bd{Y"P@6  
{ 9)={p9FZY  
bStop = true; I>X_j)  
} \D8d!gr
 
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{3Z&C$:s  
} R3;GMe@D#
 
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/* U[5  
**FileAccess.java D.G+*h@ g  
*//文件访问(定位，写) a@
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package NetFox; /M>8
ad  
import java.io.*; 3^kZydZCN  
7<&
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public class FileAccessI implements Serializable{ CA[-\>J7y  
!( xeDX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0tVZvXgTu  
RandomAccessFile oSavedFile; l_JPkM(mJw  
long nPos; pNFL;k+p}  
h@$M.h@mcG  
@;m7u
  
public FileAccessI() throws IOException /YYI 4  
{ x6A*vP0nm)  
this("",0); 7B GMG|  
} @$ E&H`da  
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public FileAccessI(String sName,long nPos) throws IOException :Mr_/t2(  
{ xk=5q|u_-  
oSavedFile = new RandomAccessFile(sName,"rw"); r=[T5,L(s  
this.nPos = nPos; A$G>D3  
oSavedFile.seek(nPos); &CW,qY,sh  
} )&[S*g  
F3/aq+<P[  
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public synchronized int write(byte[] b,int nStart,int nLen) -Y'Qa/:7  
{ mXnl-_  
int n = -1; O:'UsI1Y  
try{ j`1%a]Bwc  
oSavedFile.write(b,nStart,nLen); kmjSSh/t  
n = nLen; &i*/}OZz  
} @K`2y'#b  
catch(IOException e) GD?4/HkF  
{ 9(k5Irv"'h  
e.printStackTrace (); ]8*#%^  
} XiE  
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I, 9!["^|  
return n; 9:N@+;|T  
} Hg
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} g+h)s!$sB  
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/* uxF88$=!t  
**SiteInfoBean.java /I|.^ Id|  
*/ Eh\0gQ=  
package NetFox; e,/b&j*4th  
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hmJ{'D1"  
public class SiteInfoBean { &U:bRzD  
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private String sSiteURL; //Site's URL T% J;~|  
private String sFilePath; //Saved File's Path Fi.gf?d  
private String sFileName; //Saved File's Name -miWXEe@l  
private int nSplitter; //Count of Splited Downloading File t3!?F(&  
s"b()JP  
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public SiteInfoBean() 1qXqQA  
{//nSplitter的缺省值为5 lquY_lrri  
//default value of nSplitter is 5 ^Nl)ocHv!  
this("","","",5); FWqnlK#  
} 7g1"s1~or  
cwiHHf>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U^<\'`  
{ )3g7dtq}  
sSiteURL= sURL; ZGrjb22M  
sFilePath = sPath; ?r"][<  
sFileName = sName; sr%tEKba)  
this.nSplitter = nSpiltter; =)}m4,LA  
'j>+eA>  
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} Nx>WOb98  
>
}{'{ Z &  
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public String getSSiteURL() !<\"XxK+l  
{ @cNBY7=  
return sSiteURL; Cw1Jl5OVZ  
} =/wAk0c^y  
i1RU5IRy|j  
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public void setSSiteURL(String value) b6%T[B B  
{ iR j/Tm*T'  
sSiteURL = value; a86m?)-c  
} FtbqZN[  
j.
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T;D`=p#  
public String getSFilePath() $P#Cf&R  
{ Wlm%W>%  
return sFilePath; k{>rI2;  
} QA_SS'*  
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public void setSFilePath(String value) z-(@j;.  
{ GFd~..$  
sFilePath = value; ?d`?Ss;v  
} ZzfGs  
|0nbO2}  
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public String getSFileName() f&=y\uP]  
{ OMG.64DX .  
return sFileName; p-n_ ">7  
} .-[uQtyWW  
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public void setSFileName(String value) R:SFj!W1  
{ 5fi6>>  
sFileName = value; K|$Dnma^n  
} ^)=c74;;  
]UyIp`nV;  
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public int getNSplitter() pjr,X+6o  
{ yP2[!vYw  
return nSplitter; %m[
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} J0xOB;rd  
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public void setNSplitter(int nCount) a x1  
{ )2T?Z)"hO  
nSplitter = nCount; V~-<VM6  
}
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} v|acKux=t  
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/* #UGtYD}"  
**Utility.java a.)Gd]}g  
*/ lO},fM2j  
package NetFox; Omo1p(y  
i-!Z/,oL  
`?VtB!p@x=  
public class Utility { :Bc)1^I  
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public Utility() +P,hT  
{ w^N xR,  
l +RT>jAmK  
J<dr x_gc  
} -+4:} sD  
($:s}_<>s  
//线程睡眠 dK|6p_  
public static void sleep(int nSecond) !J ")TP=  
{ H
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try{ Gy0zh|me  
Thread.sleep(nSecond); 3Gi#WV4$  
} q:N"mp<%  
catch(Exception e) u )+;(Vd  
{ |0YDCMq(  
e.printStackTrace (); 8v)pPJr  
} v,w/g|  
} 'J~{8w,.  
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//日志 O-- "\4  
public static void log(String sMsg) aWhhq@  
{ s6SG%Vd  
System.err.println(sMsg); e$>.x< Eq  
} %lPAq  
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tcOgF:  
public static void log(int sMsg) F VW&&ft  
{ Unev[!  
System.err.println(sMsg); aRg/oA4}  
} 2ILMf?}  
} vum6O3  
88~BE ^  
Z4NNrA#  
/* HV'xDy[)  
**TestMethod.java JSX-iHhW  
*/ t4)~A5s  
package NetFox; vk\a>};  
h
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public class TestMethod { Y$SZqW0!/  
ec
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public TestMethod() =YlsJ={h  
{ ///xx/weblogic60b2_win.exe #JVw`=P  
try{ fiA_6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B6&PYMFK?*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^qXc%hjg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '5zolp%St  
fileFetch.start(); IB#L5yN r  
} `hYj0:*)S$  
catch(Exception e){e.printStackTrace ();} T7vilfO5G  
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} z zL@3/<j  
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public static void main(String[] args) bmN'{09@  
{ dWV.5cViP  
new TestMethod(); !mhV$2&r  
} ;w";s$  
} [#S[=%  
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