http断点续传简单实现（java)

/* A3s-C+@X  
**SiteFileFetch.java H/''lI{k)  
*/ k/,7FDO?m  
package NetFox; h6;vOd~%  
import java.io.*; l#|wF$J  
import java.net.*; u.rFZu?E\  
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public class SiteFileFetch extends Thread { 6qK`X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K'f`}y9  
long[] nStartPos; //开始位置 MJugno  
long[] nEndPos; //结束位置 7wz9x8\t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S3N+9*iK  
long nFileLength; //文件长度 E]c0+rh~  
boolean bFirst = true; //是否第一次取文件 }l<:^lX  
boolean bStop = false; //停止标志 ko+fJ&$  
File tmpFile; //文件下载的临时信息 TMw6 EM  
DataOutputStream output; //输出到文件的输出流 }MIg RQ9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EN/r{Cm$B  
public SiteFileFetch(SiteInfoBean bean) throws IOException mhW*rH*m  
{ }Hy4^2B  
siteInfoBean = bean; ncdj/C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #t<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r0/aw  
if(tmpFile.exists ()) )F'r-I%Hi  
{ 77H"=  
bFirst = false; n%K^G4k^  
read_nPos(); rGmxK|R  
} z]HaE|j}S  
else 1{-yF :A
 
{ bZlKy`Z  
nStartPos = new long[bean.getNSplitter()]; K:q|M?_  
nEndPos = new long[bean.getNSplitter()]; Y|nC_7&Bv  
} r?2J 
 
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} l}_6_g>6  
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public void run() fJD+GvV$x  
{ ?)O!(=6%'  
//获得文件长度 0)]?@"j  
//分割文件 _^@>I8ix  
//实例FileSplitterFetch ["WWaCcx  
//启动FileSplitterFetch线程 U28frRa  
//等待子线程返回 "_ H9]}Q  
try{ tLzb*U8'1w  
if(bFirst) E RjMe'q4  
{ k"F\4M  
nFileLength = getFileSize(); p+#]Jr  
if(nFileLength == -1) S0w:R:q}L  
{ !:3X{)4  
System.err.println("File Length is not known!"); V.}3d,Em%]  
} fk2p}  
else if(nFileLength == -2) L>&9+<-B  
{ c&'5r OY~  
System.err.println("File is not access!"); [w{x+6uX'  
} .~,=?aq^  
else -T2w?|  
{ O"~CZh,:r}  
for(int i=0;i<nStartPos.length;i++) KnC:hus  
{ F$@(0c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _c>8y  
} 4SJb\R)XK  
for(int i=0;i<nEndPos.length-1;i++) I~Q G  
{ <.=-9O6  
nEndPos = nStartPos[i+1];   bKt4  
}
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nEndPos[nEndPos.length-1] = nFileLength; ~oz??SX  
} 3
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} Ejj+%)n.  
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//启动子线程 >';UF;\5]Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +1nzyD_E  
for(int i=0;i<nStartPos.length;i++) }=p+X:k=  
{ GL,( N|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l#TE$d^ym  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "t%Jj89a\  
nStartPos,nEndPos,i); F^CR$L& K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t!\B6!Fo  
fileSplitterFetch.start(); &3 *#h  
} ?N=`
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;r}yeISf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R(f6uO!m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @?*; -]#)  
nEndPos = " + nFileLength); ^$s&bH'8  
// fileSplitterFetch[nPos.length-1].start(); e2kW,JV/<$  
}H:wgy`  
ej,R:}C%`  
//等待子线程结束 Y)2#\ F  
//int count = 0; (_=R<:  
//是否结束while循环 {uurLEe?  
boolean breakWhile = false; 3.6Gh
|7  
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while(!bStop) uyvjo)T  
{ o(yyj'=(  
write_nPos(); 0UhJ I  
Utility.sleep(500); %D3Asw/5a  
breakWhile = true; Nx"|10gC  
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for(int i=0;i<nStartPos.length;i++) \. a7
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{ $f=6>Kn|^]  
if(!fileSplitterFetch.bDownOver) ~l}\K10L*  
{  9XhcA  
breakWhile = false; 3)y=}jw  
break; o,RiAtdk  
} #,h0K  
} W3jwc{lj  
if(breakWhile) C{~O!^2G  
break; 7^<6|>j4  
+F*h\4ry#  
q6}KOO)  
//count++; NAOCQDk{  
//if(count>4) 7^C&2k5G  
// siteStop(); -vv_6ZL[  
} W;?e@}  
OZEbs 7  
9"zp>VR  
System.err.println("文件下载结束！"); $b)t`r+  
} (4|R}jv  
catch(Exception e){e.printStackTrace ();} n`V?n  
} qRHT~ta-?  
={;7WB$  
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//获得文件长度 &ET$ca`j#  
public long getFileSize() $Z3{D:-)  
{ [5]n,toAh  
int nFileLength = -1; pj$kSS|m6-  
try{ Yl=-
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URL url = new URL(siteInfoBean.getSSiteURL()); >[;L.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8nwps(3  
httpConnection.setRequestProperty("User-Agent","NetFox"); r7FJ
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int responseCode=httpConnection.getResponseCode(); 0lV;bVa%  
if(responseCode>=400) Mh MXn;VKj  
{ HPg%v|  
processErrorCode(responseCode); }<zbx*!  
return -2; //-2 represent access is error a#lytp  
} r
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YFDOp*  
String sHeader;  DTa!vg  
7$x%A&]  
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for(int i=1;;i++) =R"LB}>h}  
{ _l+C0lQ
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tEt
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//Utility.log(in.readLine());  O*.n;_&  
sHeader=httpConnection.getHeaderFieldKey(i); P-<1vfThH  
if(sHeader!=null)  n(|rs  
{ :^U>n{
 
if(sHeader.equals("Content-Length")) y06xl:iQwF  
{ @v3)N[|d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z$Le,+  
break; qHT73_R  
} }=Xlac_U  
} )5n:UD{f[#  
else Q @[gj:w  
break; B&_Z&H=  
} I0qJr2[X~  
} [$td:N *  
catch(IOException e){e.printStackTrace ();} jo3(\Bq  
catch(Exception e){e.printStackTrace ();} 0+u>"7T  

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Utility.log(nFileLength); yz,0 S'U  
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return nFileLength; v+}${h9  
} :L
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_#MKpH  
//保存下载信息（文件指针位置） /DP0K @%  
private void write_nPos() o 0T1pGs'  
{ gf?N(,  
try{ sT "q]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i+pQ 7wx  
output.writeInt(nStartPos.length); ec/>LJDX7  
for(int i=0;i<nStartPos.length;i++) 29CzG0?B  
{ K|OPtYeb  
// output.writeLong(nPos); z 2jC48~  
output.writeLong(fileSplitterFetch.nStartPos); >2= Y 35j  
output.writeLong(fileSplitterFetch.nEndPos); 7WUvO  
} GgnR*DVP$  
output.close(); C|2|OTtQ  
} ~mwIr  
catch(IOException e){e.printStackTrace ();} >#'?}@FWQN  
catch(Exception e){e.printStackTrace ();} ^b}Wl0Fn  
} Od^Sr4C  
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//读取保存的下载信息（文件指针位置） 8Lgm50bs  
private void read_nPos() S4?WR+:h  
{ jVZ<i}h0B  
try{ Pf<yLT]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L[
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int nCount = input.readInt(); r;MFVj{  
nStartPos = new long[nCount]; aEh9za  
nEndPos = new long[nCount]; ||.Hv[ ]V*  
for(int i=0;i<nStartPos.length;i++) %K.rrn M  
{ N3*1,/,l.  
nStartPos = input.readLong(); G "!v)o  
nEndPos = input.readLong(); ?L0k|7  
} WUo\jm[yr  
input.close(); `34{/}w  
} Ok|Dh;1_  
catch(IOException e){e.printStackTrace ();} VIN0kRQ#  
catch(Exception e){e.printStackTrace ();} bar=^V)  
} 8ZqLGa]  
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private void processErrorCode(int nErrorCode) + d
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{ pT3icy!A=  
System.err.println("Error Code : " + nErrorCode); $45.*>,  
} k3nvML,bv  
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, ,ng]&%i  
//停止文件下载 eV/oY1B]<  
public void siteStop() Dte5g),R  
{ U8y?S]}vo  
bStop = true; R&&&RI3{  
for(int i=0;i<nStartPos.length;i++) jWV}Ua  
fileSplitterFetch.splitterStop(); yP>025o't  
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} E`V\/`5D  
} ^]'_Qbi]}  
//负责部分文件的抓取 esQ$.L
 
**FileSplitterFetch.java "tl$JbRTY  
*/ t*-cX  
package NetFox; bk;uKV+<  
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import java.io.*; kd\Hj~*  
import java.net.*; ;^0rY)&  
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public class FileSplitterFetch extends Thread { S4[#[w`=  
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String sURL; //File URL ;b~\[  
long nStartPos; //File Snippet Start Position (_<,Oj#*S  
long nEndPos; //File Snippet End Position t89Tt@cf  
int nThreadID; //Thread's ID t|i<}2  
boolean bDownOver = false; //Downing is over noL9@It0  
boolean bStop = false; //Stop identical M@<9/xPS  
FileAccessI fileAccessI = null; //File Access interface f,Dic%$q  
X(X[v]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3Jlap=]68S  
{ 4oueLT(zc  
this.sURL = sURL; O!{YwE8x9  
this.nStartPos = nStart; Bt(<Xj D  
this.nEndPos = nEnd;
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nThreadID = id; !khEep}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1' v!~*af  
} 6h,!;`8O  
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public void run() `&7tADFB  
{ D9A%8o  
while(nStartPos < nEndPos && !bStop) jVQ89vf ~  
{ f$:SacF  
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try{ L YF|  
URL url = new URL(sURL); P/|1,Sk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %dg[ho  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,xVAJ6_#  
String sProperty = "bytes="+nStartPos+"-"; {.jW"0U  
httpConnection.setRequestProperty("RANGE",sProperty); )y;7\-K0  
Utility.log(sProperty); matna  
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InputStream input = httpConnection.getInputStream(); ocJG4#  
//logResponseHead(httpConnection); 9jqsEd-SW  
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byte[] b = new byte[1024]; v[^8_y}A`  
int nRead; 9 %4:eTcp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;tZQ9#S  
{ ^PezV5(  
nStartPos += fileAccessI.write(b,0,nRead); 4fC:8\A  
//if(nThreadID == 1) @r/~Y]0Ye5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qJrKt=CE  
} $=N?[h&4  
/B~[,ES@1  
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Utility.log("Thread " + nThreadID + " is over!"); ]4en|Aq  
bDownOver = true; n"6L\u  
//nPos = fileAccessI.write (b,0,nRead); XDPgl=~  
} X(*O$B{ R  
catch(Exception e){e.printStackTrace ();} bNVeL$'  
} w,FPL&{  
} &4S2fWx  
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//打印回应的头信息 /}m*|cG/  
public void logResponseHead(HttpURLConnection con) o!":mJy  
{ y7fy9jQ 8.  
for(int i=1;;i++) SnmUh~`L~  
{ %}VH5s9\  
String header=con.getHeaderFieldKey(i); D4[t^G;J  
if(header!=null) {ptHk<K:)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @e GBF Ns  
Utility.log(header+" : "+con.getHeaderField(header)); >VkBQM-%  
else 3}8o 9  
break; 0~^RHb.NA8  
} mQ"uG?NE  
} pLtw|S'4  
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public void splitterStop() m)Kg6/MV.  
{ r9})~>   
bStop = true; 5P-t{<]tx  
} ([dd)QU  
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} 4v hz`1  
/GC&@y0yi  
src+z#  
/* ~EPVu  
**FileAccess.java x~!|F5JbM  
*//文件访问(定位，写) " L`)^  
package NetFox; &b
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import java.io.*; "U-jZ5o"  
5z!$=SFz  
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public class FileAccessI implements Serializable{ bT^dtEr[  
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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 Xi98:0<=  
RandomAccessFile oSavedFile; 0yI1r7yNB+  
long nPos; njaMI8|Pa  
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public FileAccessI() throws IOException /D3{EjUE=  
{ VE|l;aXi  
this("",0); _V-KyK  
} p/HDG ^T:u  
Ec@n<KK#  
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public FileAccessI(String sName,long nPos) throws IOException Szgo@x$^  
{ wwB3m&  
oSavedFile = new RandomAccessFile(sName,"rw"); Lz'VQO1U=  
this.nPos = nPos; MxIa,M<  
oSavedFile.seek(nPos); QS&B"7;g  
} rTIu'  
6(f'P_*  
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public synchronized int write(byte[] b,int nStart,int nLen) Y#ZgrziYM  
{ [7FG;}lB-  
int n = -1; ]$@D=g,r  
try{ w#|L8VAh  
oSavedFile.write(b,nStart,nLen); i.vH$  
n = nLen; R}M ;, G  
} IT_I.5*A2  
catch(IOException e) :
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{ =Xh)34q  
e.printStackTrace (); @i1e0;\  
} I4X9RYB6c  
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return n; h^yqrDyJ  
} `GCoi ?n7  
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} N7+L@CC6T  
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/* ?dgyi4J?=`  
**SiteInfoBean.java Q!e560@  
*/
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package NetFox; `r`8N6NQ&]  
:}lqu24K  
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public class SiteInfoBean { FPDTw8" B;  
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vjuFVJwL  
private String sSiteURL; //Site's URL 50^ux:Uv+N  
private String sFilePath; //Saved File's Path  p+h$]CH  
private String sFileName; //Saved File's Name ]dpL PR  
private int nSplitter; //Count of Splited Downloading File ;Y?MbD  
hJ@vlMW  
a[-!X7,IU  
public SiteInfoBean() 69g{oo  
{//nSplitter的缺省值为5 `t~jHe4!Y  
//default value of nSplitter is 5 !*N9PUM  
this("","","",5); <1D|TrP  
} ]%' AZ`8  
Qd[_W^QI  
1UP=(8j/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tJ\ $
%  
{ a#YK1n[!  
sSiteURL= sURL; zfeT>S+  
sFilePath = sPath; ky2 bj}"p9  
sFileName = sName;   Q.g/  
this.nSplitter = nSpiltter; FE~D:)Xj'?  
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_QPqF{iI  
} )>iOj50n3  
FZr/trP~  
9zu;OK%  
public String getSSiteURL() :!%VSem  
{ HZyA\FS  
return sSiteURL; oN7SmP_  
} Z}J5sifr  
$Habhw  
e8F]m`{_"  
public void setSSiteURL(String value) }aZuCe_  
{ >HP `B2Q H  
sSiteURL = value; b(iF0U>&  
} )kpEcMlR  
N~v6K}`}  
wVBKVb9N  
public String getSFilePath() d1<";b2Jt^  
{ -50DGA,K6  
return sFilePath; Hr|f(9xA  
} <^5!]8*O  
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bdg6B7%Q  
public void setSFilePath(String value) /( Wq  
{ zBF~:Uc`B  
sFilePath = value; u_(~zs.N]  
} IiU>VLa  
XB)D".\  
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public String getSFileName() {213/@,  
{ NAGM3{\5v$  
return sFileName; |&; ^?M  
} QL?_FwZL  
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f9.?+.^_  
public void setSFileName(String value) hyI7X7Hy  
{ (8duV  
sFileName = value; aZFpt/.d  
} $DbnPZ2$  
17LhgZs&  
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public int getNSplitter() rq+_[!
 
{ xe@1H\7:  
return nSplitter; y>I2}P  
} l5[5Y6c>  
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public void setNSplitter(int nCount) >>U>'
}@Q  
{ LOh2eZ"
n  
nSplitter = nCount; M<vPE4TIr*  
} SyWZOE%p  
} @)Qgy}*5  
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K d&/9<{>  
/* d)o5JD/  
**Utility.java E }L Hp  
*/ `|dyT6V0I_  
package NetFox; L)e"qC_-  
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public class Utility { pgU[di  
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,;k+n)  
public Utility() osW"wh_
  
{ >B BV/C'9  
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} ;tOsA
#  
^_2c\mw_I  
//线程睡眠 CMt<oT6.?  
public static void sleep(int nSecond) $O"ss>8Se  
{ z0z@LA4k6@  
try{ Qb536RpcTY  
Thread.sleep(nSecond); E&M(QX5  
} -+R,="nRQ  
catch(Exception e) vObZ|>.J~O  
{ MmF&jd-=  
e.printStackTrace (); w#A)B<Y/"  
} [!'+}  
} AO#9XDEM  
YpZB-9Krf  
//日志 1"h"(dA  
public static void log(String sMsg) ;Qi:j^+P)  
{ =pH2V^<<#  
System.err.println(sMsg); DIC*{aBf  
} a<cw
rDZ  
amBg<P`'_  
!/FRL<mp  
public static void log(int sMsg) l_I)d7  
{ Gm~([Ln{  
System.err.println(sMsg); ohx[_}xN  
} /*0t_  
} 7^L  
^Q/*on;A,/  
je] DR~  
/* '&IGdB I  
**TestMethod.java ,AP&N'  
*/ qZ1'uln=C-  
package NetFox; )6"}M;v  
K-RmB4WI  
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public class TestMethod { JZ5k3#@e  
N\{"&e  
O]N/(pe:d  
public TestMethod() |]\zlH"w  
{ ///xx/weblogic60b2_win.exe fY<#KM6X  
try{ AwM`[`R
eE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `7"="T~ *  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5pQpzn=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `fv5U%  
fileFetch.start(); Q\Ek U.[I  
} /%@;t@BK4  
catch(Exception e){e.printStackTrace ();} >eJ<-3L;  
1J?v\S$ma`  
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} .9
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public static void main(String[] args) 2 bc&sU)X  
{ hU?DLl:bXF  
new TestMethod(); MAh1tYs4D
 
}
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} K_i|cYGV  
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