http断点续传简单实现（java)

/* p~n62(  
**SiteFileFetch.java S? -6hGA j  
*/ D7D:?VoR  
package NetFox; |f:1Br  
import java.io.*; 4x`.nql  
import java.net.*; h
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public class SiteFileFetch extends Thread { ?89K [D|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Dd3GdG@*~  
long[] nStartPos; //开始位置 :`pgdn  
long[] nEndPos; //结束位置 0[f8Gb3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7$z]oVbO'  
long nFileLength; //文件长度 =54"9*  
boolean bFirst = true; //是否第一次取文件 $.7Ov|  
boolean bStop = false; //停止标志 1>KZ1Kf  
File tmpFile; //文件下载的临时信息 h{J=Rq  
DataOutputStream output; //输出到文件的输出流 aSN"MTw.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yF~iVt  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6N6}3J5  
{  QB/H  
siteInfoBean = bean; u?ALZxj?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q ,C)AZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W)RCo}f  
if(tmpFile.exists ()) #QWG5  
{ "JH /ODm  
bFirst = false; o 0-3[W'x<  
read_nPos(); Cwb}$=p'  
} )kBN]>&R  
else
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{ \-Oq/g{j  
nStartPos = new long[bean.getNSplitter()]; /3(|P  
nEndPos = new long[bean.getNSplitter()]; Po ,zTz  
} X;~3 U 9  
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} X-Yy1"6m1  

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public void run() |uT&M`7\{  
{ g[#4`Q<.  
//获得文件长度 Zx1I&K\Cd  
//分割文件 (_9cL,v  
//实例FileSplitterFetch nVO|*Bnf)  
//启动FileSplitterFetch线程 @CxXkR  
//等待子线程返回 e5"?ol0  
try{ ^Hdru]A$2  
if(bFirst) &fIx2ZM[  
{ Ah_Ttj  
nFileLength = getFileSize(); ",qcqG(  
if(nFileLength == -1) b8>2Y'X  
{ JfrPK/Vn  
System.err.println("File Length is not known!"); zvDg1p  
} !9n!:"(r  
else if(nFileLength == -2) N?RJuDW  
{ |%i|P)]  
System.err.println("File is not access!"); #S*@RKSE|7  
} A`H&"A  
else ]tu:V,q  
{ o#X=1us  
for(int i=0;i<nStartPos.length;i++) *Dz<Pi^  
{ 'QMvj` -  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jn+M L&  
} kW 7$  
for(int i=0;i<nEndPos.length-1;i++) 3 zF"GT  
{ '&|]tu:q  
nEndPos = nStartPos[i+1]; N9[2k.oBH  
} "I7 Sed7  
nEndPos[nEndPos.length-1] = nFileLength; OLl?1  
} Dd=iYMm7  
} ITq$8  
x+X^K_*  
Y!+q3`-%T  
//启动子线程 q%RPAe  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E&RiEhuv  
for(int i=0;i<nStartPos.length;i++) 0Xke2
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{ T VuDK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "%,KZI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DaK2P;WP  
nStartPos,nEndPos,i); PCx] >&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y5v}EX`m&  
fileSplitterFetch.start(); MgP6ki1z  
} nVK`H@5fw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t!u{sr{j=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); nJ ZQRRa:C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?eU=xO  
nEndPos = " + nFileLength); gmU0/z3&  
// fileSplitterFetch[nPos.length-1].start(); Gp PlO]  
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k *#fN(_  
//等待子线程结束 z1WF@Ej  
//int count = 0; Hf ]w  
//是否结束while循环 clcj5
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boolean breakWhile = false; 4)IRm2
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while(!bStop) (16U]s  
{ ?9?eA^X%  
write_nPos(); 6?CBa]QG  
Utility.sleep(500); =LsW\.T6  
breakWhile = true; 9AbSt&#  
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for(int i=0;i<nStartPos.length;i++) ? 7H'#l  
{ v)TFpV6b{p  
if(!fileSplitterFetch.bDownOver) EZz`pE  
{ }EW@/; kC  
breakWhile = false; M< T[%)v  
break; rLy<3  
} 7n_'2qY  
} ZgXn8O[a  
if(breakWhile) T9N&Nh7 3  
break; Ao%;!(\I%  
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Vd'KN2Jm  
//count++; _;M46o%h  
//if(count>4) c<(LXf+61  
// siteStop(); )/:r$n7  
} XHN`f#(w  
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System.err.println("文件下载结束！"); upJ|`,G{  
} :N3'$M"  
catch(Exception e){e.printStackTrace ();} /!u#S9_B  
} Q]?Lg  
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5_d=~whO&2  
//获得文件长度 [CfA\-gx<f  
public long getFileSize() =>PBdW  
{ * MJl(  
int nFileLength = -1; @k~_ w#  
try{ }iK_7g`yKa  
URL url = new URL(siteInfoBean.getSSiteURL()); 6]#\|lds1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !A6l\_  
httpConnection.setRequestProperty("User-Agent","NetFox"); *@C4~Zo  
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int responseCode=httpConnection.getResponseCode(); A(xCW+h@)  
if(responseCode>=400) (4U59<ie  
{ Ix"hl0Kh  
processErrorCode(responseCode); )ZU=`!4  
return -2; //-2 represent access is error L 1fK  
} fO4e[g;G  
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String sHeader; s 4Mi9h_  
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for(int i=1;;i++) qlUw;{;p  
{ 6iozb~!Rr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BBub'  
//Utility.log(in.readLine()); Qe~2'Hw#9  
sHeader=httpConnection.getHeaderFieldKey(i); Qoj}]jve  
if(sHeader!=null) 8Jz/'  
{ a-`OE"  
if(sHeader.equals("Content-Length")) .45XS>=z#  
{ cI5*`LML1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #&@qmps(T  
break; O$><E8q  
} t*fG;YOg  
} +3c!.] o;  
else x bG'![OX  
break; %Jrdr`<  
} NMSpi[dr  
} UL/|!(s  
catch(IOException e){e.printStackTrace ();} O\5*p=v  
catch(Exception e){e.printStackTrace ();} ]g>@r
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Utility.log(nFileLength); a?+Ni|+  
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return nFileLength; )$#r6fQO  
} dh7PpuN{  
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//保存下载信息（文件指针位置） /nK)esB1L  
private void write_nPos() bw@DcT&,  
{ qM`XF32A$  
try{ _{EO9s2FG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ez2 gy"  
output.writeInt(nStartPos.length); seFug  
for(int i=0;i<nStartPos.length;i++) 5(/
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{ ;%1ob f 89  
// output.writeLong(nPos); [;c'o5M&  
output.writeLong(fileSplitterFetch.nStartPos); a0"gt"qA  
output.writeLong(fileSplitterFetch.nEndPos); C?n3J  
} 1MtvnPY  
output.close(); W#<&(s4  
} `ag7xd!  
catch(IOException e){e.printStackTrace ();} $jYwV0  
catch(Exception e){e.printStackTrace ();} vT<q zN  
} 5XNIX)H  
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//读取保存的下载信息（文件指针位置） JJnZbJti  
private void read_nPos() SL;\S74  
{ Z=O2tR  
try{ 7Q<uk[d0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +uF!.!}  
int nCount = input.readInt(); ~Od4( }/G  
nStartPos = new long[nCount]; Sx,O)  
nEndPos = new long[nCount]; :E|HP#iwu  
for(int i=0;i<nStartPos.length;i++) 1i}Rc:  
{ mT.p-C  
nStartPos = input.readLong(); ?VMj;+'tr  
nEndPos = input.readLong(); U~8.uldnF  
} S9Fg0E+J  
input.close(); v
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} [aF?1KxNMt  
catch(IOException e){e.printStackTrace ();} x@+m_y  
catch(Exception e){e.printStackTrace ();} -jB1tba  
} oZO6J-ea  
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private void processErrorCode(int nErrorCode) xMsos?5}  
{ w5l:^^zF(  
System.err.println("Error Code : " + nErrorCode); ~U:{~z  
} {xw*H<"f<  
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//停止文件下载 4C(vBKl  
public void siteStop() NyD[9R?  
{ D4yJ:ATO&  
bStop = true; 7N^9D H{`  
for(int i=0;i<nStartPos.length;i++) e~r%8.Wm  
fileSplitterFetch.splitterStop(); 5_+vjV;5  
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} ,\;;1Kq  
} 'Y+AU#1~H  
//负责部分文件的抓取 ,ZcW+!  
**FileSplitterFetch.java zCD?5*7  
*/ 07"dU  
package NetFox; \5^#5_<  
lKs*KwG  
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import java.io.*; \4wM8j  
import java.net.*; m",wjoZe*  
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public class FileSplitterFetch extends Thread { { p {a0*$5  
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String sURL; //File URL [ADr _  
long nStartPos; //File Snippet Start Position ;YxQo o>  
long nEndPos; //File Snippet End Position v*5n$UFV  
int nThreadID; //Thread's ID W|@EKE.k  
boolean bDownOver = false; //Downing is over (US]e un  
boolean bStop = false; //Stop identical sk!v!^\_r  
FileAccessI fileAccessI = null; //File Access interface Wy%q9x]}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zIWw055W  
{ SsDz>PP  
this.sURL = sURL; v'B++-%  
this.nStartPos = nStart; o)KF+[^  
this.nEndPos = nEnd; buGW+TrWY  
nThreadID = id; 3%m2$\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ykSn=0  
} 5O&6 (Gaf  
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public void run() <Mo_GTOC!  
{ ]{
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while(nStartPos < nEndPos && !bStop) |")}p=   
{ [JFmhLP9  
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try{ z8M^TV  
URL url = new URL(sURL); g^(wZ$NH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9iWDEk  
httpConnection.setRequestProperty("User-Agent","NetFox"); $j^Jj  
String sProperty = "bytes="+nStartPos+"-"; xA]CtB*o7  
httpConnection.setRequestProperty("RANGE",sProperty); <CJua1l\  
Utility.log(sProperty); gF1qZ=<  
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InputStream input = httpConnection.getInputStream(); {zBf*x  
//logResponseHead(httpConnection); aksyr$d0V<  
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byte[] b = new byte[1024]; jcQ{,9 H`l  
int nRead; l2>G +t(,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^8aj\xe(  
{ _{&znXf>?6  
nStartPos += fileAccessI.write(b,0,nRead); _n_lO8mK  
//if(nThreadID == 1) 7f#
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QJp _>K  
} 6}  !n0  
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Utility.log("Thread " + nThreadID + " is over!"); ?"PUw3V3lB  
bDownOver = true; `@ULG>   
//nPos = fileAccessI.write (b,0,nRead); "aK3 ylz;  
} DDn@M|*$  
catch(Exception e){e.printStackTrace ();} }6.R.*Imz  
} :kqJ~  
} Dna0M0   
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//打印回应的头信息 ~WU _u,:  
public void logResponseHead(HttpURLConnection con) U?JZ23>bbw  
{ >- ]tOH,0  
for(int i=1;;i++) 4&)*PKq  
{ ]uX'[Z}t  
String header=con.getHeaderFieldKey(i); q=ZLSBZ  
if(header!=null) `w6\II)aB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z`((l#(  
Utility.log(header+" : "+con.getHeaderField(header)); eIK8J,-  
else +ZtqR  
break; xn1  
} G!k&'{2  
} vGO-a2Z  
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public void splitterStop() 8AT;9wZqt  
{ |{+D65R  
bStop = true; #9}E@GGs  
} 9=pG$+01OR  
! lgsV..R  
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} qI\qpWS\  
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/* EcrM`E#kaZ  
**FileAccess.java V"(S<o  
*//文件访问(定位，写) $q]((@i.  
package NetFox; {MU>5\  
import java.io.*; .2/(G{}U  
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public class FileAccessI implements Serializable{ G`PSb<h\oc  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0e9W>J9  
RandomAccessFile oSavedFile; 1w'iD X  
long nPos; ~F^=7oq  
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public FileAccessI() throws IOException AZz }  
{ 7$WO@yOsh  
this("",0); !=--pb  
} GM|gm-t<@  
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public FileAccessI(String sName,long nPos) throws IOException G*uy@s:  
{ e*jt(p[Ge  
oSavedFile = new RandomAccessFile(sName,"rw"); NmYSk6kWJ  
this.nPos = nPos; rc1EJ(c  
oSavedFile.seek(nPos); Um]>B`."wK  
} u&?J+  
]7
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public synchronized int write(byte[] b,int nStart,int nLen) 1u75  
{ x:b0G  
int n = -1; +"6_rbeuO  
try{ !L:!X88  
oSavedFile.write(b,nStart,nLen); /lkIbmV  
n = nLen; 7)S`AQ2:)  
} xekW-=#a7-  
catch(IOException e) S:/;|D
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{ 2;r(?ebw  
e.printStackTrace (); n?_!gqK  
} hL~@Ah5&t  
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return n; \ F#mwl,>"  
} Q\&FuU  
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} frbKi _1  
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/* JDfkm+}uY  
**SiteInfoBean.java |4aV~n[>#  
*/ f!a[+^RB:  
package NetFox; Q ,30  
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public class SiteInfoBean { &0SX*KyI  
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private String sSiteURL; //Site's URL )dgXS//Y  
private String sFilePath; //Saved File's Path A-1Wn^,>*  
private String sFileName; //Saved File's Name F2]v]]F!  
private int nSplitter; //Count of Splited Downloading File K#H}=Y A  
:&}(?=<R}L  
7SLJLn3d  
public SiteInfoBean() /9NQ u  
{//nSplitter的缺省值为5 I8@NQ=UV0  
//default value of nSplitter is 5 &1Y

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this("","","",5); PN[ `p1F  
} 1%Xwk2l,8b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (xpj?zlmM  
{ =`[08  
sSiteURL= sURL; =Ig'Aw$x  
sFilePath = sPath; v Ic0V  
sFileName = sName; mv|eEz)r  
this.nSplitter = nSpiltter; W!8g.r4u+,  
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} _fha9`  
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public String getSSiteURL() L22GOa0  
{ Pf;'eOdp  
return sSiteURL; jnsV'@v8Nj  
} vJVL%,7  
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public void setSSiteURL(String value) _" W<>  
{ 8-5MGh0L  
sSiteURL = value; MO&QR-OY  
} e}yoy+9  
r,X5@/  
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public String getSFilePath() -jnx0{/  
{ |ybW  
return sFilePath; W.TZU'%  
} 87P{vf#  
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public void setSFilePath(String value) ]C_g:|q  
{ #7I,.DUy[  
sFilePath = value; 7yo/sb9h  
} X5UcemO  
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PhW<)B]  
public String getSFileName() 3IQ)%EN  
{ <-62m8N|  
return sFileName; &54fFyJF  
} w|:UTJ>@  
..6 : _{wg  
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public void setSFileName(String value) 4of3#M  
{ Ac;rMwXk#  
sFileName = value; c;c'E&9P]  
} R+k-mbvnt  
vKN"o* q  
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public int getNSplitter() oV
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{ gXN#<g,:^  
return nSplitter; ]Aap4+s  
} E;$)Oz  
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public void setNSplitter(int nCount) qYv/" 1  
{ sKYb&2wJ  
nSplitter = nCount; ',j'Hf  
} wr{03mQHxp  
} f>\OT  
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/* LW6&^S?4{  
**Utility.java =S/$h}Vi  
*/ maQE Bi,  
package NetFox; >yFEUD:  
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public class Utility { N|hNh$J[  
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public Utility() _h>S7-X  
{ Rr! PU  
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@/h_v#W  
} )R$+dPu>  
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//线程睡眠 P\\4 w)C  
public static void sleep(int nSecond) 2`>/y  
{ TY~8`+bJ  
try{ N1$lG? )+  
Thread.sleep(nSecond); 'U ',9  
} U ^1Xc#Ff  
catch(Exception e) ~01 o  
{ TP'  
e.printStackTrace (); V\^rs41$;  
} /.
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} D>M a3g  
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//日志 4DI.RK9  
public static void log(String sMsg)
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{ h- .V[]<  
System.err.println(sMsg); 3
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} (7BG~T
 
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public static void log(int sMsg) m^cr-'  
{ W5,e;4/hL  
System.err.println(sMsg); T|^rFaA  
} jqq96hP,  
} 4zuM?Dp  
tiG=KHK%o  
*A C){M  
/* dr0<K[S_  
**TestMethod.java kbzzage6L  
*/ IJHNb_Cku  
package NetFox; @ hH;d\W#  
2[f8"'lUQ  
?dMyhU}  
public class TestMethod { ?B ;+,  
G)5w_^&%  
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public TestMethod() GJz d4kj  
{ ///xx/weblogic60b2_win.exe Z$!>hiz2  
try{ B:S/ ?v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *sK")Q4N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kKr|PFz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I>ks H  
fileFetch.start(); X`bN/sI  
} _j{^I^P  
catch(Exception e){e.printStackTrace ();} i zJa`K  
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} )RA$E`!b  
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public static void main(String[] args) x'Pp!  
{ *,qW9z  
new TestMethod(); S <~"\<ED  
} X,VOKj.%  
} '>dsROB->  
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