http断点续传简单实现（java)

/* LmE%`qNg  
**SiteFileFetch.java `md)|PSU  
*/ u(iEuF;7  
package NetFox; =~}\g;K1Q  
import java.io.*; l*V]54|ON3  
import java.net.*; ZV=O oLt,  
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public class SiteFileFetch extends Thread { z UN&L7D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Eh/B[u7T[  
long[] nStartPos; //开始位置 Jn!-Wa,  
long[] nEndPos; //结束位置 pB*8D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !A!}j.s  
long nFileLength; //文件长度 lJ1_Zs `  
boolean bFirst = true; //是否第一次取文件 rG)K?B~  
boolean bStop = false; //停止标志 /D2 cY>  
File tmpFile; //文件下载的临时信息 jYE<d&Cq  
DataOutputStream output; //输出到文件的输出流 mhU ?
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） TN!8J=sx.  
public SiteFileFetch(SiteInfoBean bean) throws IOException Awy-kou[C  
{ n3Uw6gLD  
siteInfoBean = bean; WxO2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  &ig6\&1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k<xPg5  
if(tmpFile.exists ()) 'e @`HG  
{ 8NU<lV`  
bFirst = false; `P/7Mf  
read_nPos(); R <Mvwu  
} ^I2+$  
else )*6]m1  
{ $hv o
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nStartPos = new long[bean.getNSplitter()]; ++{,1wY\  
nEndPos = new long[bean.getNSplitter()]; y*ux7KO  
} ;QZ}$8D6Q  
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} IXQxjqd^  
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public void run() ^xz*%2@  
{  NW$_w  
//获得文件长度 V!^5#A<  
//分割文件 _4+'@u #  
//实例FileSplitterFetch E(%_aFx>/  
//启动FileSplitterFetch线程 (tY0/s  
//等待子线程返回 M^C|
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try{ O4Z_v%2M  
if(bFirst) Lt8J^}kwl  
{ 6sE%]u<V  
nFileLength = getFileSize(); p0r:U<&  
if(nFileLength == -1) '+8`3['  
{ I;u1my
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System.err.println("File Length is not known!"); q-t
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} ',>Pz+XKc  
else if(nFileLength == -2) 98Dg[O  
{ 3Ql77?&k  
System.err.println("File is not access!"); +c+i~5B4  
} ;^yR,32F  
else E$8D^Zt  
{ JSf \ApX  
for(int i=0;i<nStartPos.length;i++) )P|&o%E  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); PjxZ3O  
} _zuX6DO  
for(int i=0;i<nEndPos.length-1;i++) C*C;n4AT  
{ B)!ty"  
nEndPos = nStartPos[i+1]; 3 *g>kRMJ  
} I=;.o>  
nEndPos[nEndPos.length-1] = nFileLength; Q)lN7oD  
} BSyl!>G6n8  
} 45 \W%8  
sFrerv&0  
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//启动子线程 D~^P}_e.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,JU3w  
for(int i=0;i<nStartPos.length;i++) Q"(*SA+-|  
{ QGq8r>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O~udlVn<6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LtK= nK  
nStartPos,nEndPos,i); m ?)k&{I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @,\J\ rb  
fileSplitterFetch.start(); ?D?ldg  
} (H[.\O-`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K5"8zF)*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &;x*uG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kWZ@v+Mk3  
nEndPos = " + nFileLength); o1k X`Eu  
// fileSplitterFetch[nPos.length-1].start(); #s}&  
:svKE.7{  
mD"[z}r)  
//等待子线程结束 gXb * zt2  
//int count = 0; FdcmA22k*  
//是否结束while循环 [11D7L%1t  
boolean breakWhile = false; xj#anr  
=1SG^rp  
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while(!bStop) 6eB2mcV  
{ 3ss0/\3P  
write_nPos(); lK2=[%,~  
Utility.sleep(500); J=`2{ 'l  
breakWhile = true; n@PXC8}  
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+N>z|T<  
for(int i=0;i<nStartPos.length;i++) ;x
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{ +YFAZv7`  
if(!fileSplitterFetch.bDownOver) }fqy vI  
{ tupAU$h?!  
breakWhile = false; C&/_mm
5  
break; W>'KE:!sp  
} K @h94Ni6  
} .`TDpi9OB  
if(breakWhile) mr[+\ 5  
break; v"v-c!k  
v~AD7k2{8  
kBlk^=h<:w  
//count++; :< *xG&  
//if(count>4) 8iwH^+h~  
// siteStop(); n5z";:p  
} J
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=c34MY(#X  
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System.err.println("文件下载结束！"); /V"6Q'D  
} $a.,;:  
catch(Exception e){e.printStackTrace ();} %s),4  
} Id<O/C  
k"pN  
*a2-
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//获得文件长度 ClWxL#L6~  
public long getFileSize() gnWEsA\!  
{ G]k+0&X  
int nFileLength = -1; 6Z>G%yK  
try{ `Re{j{~s  
URL url = new URL(siteInfoBean.getSSiteURL()); *Me&>"N"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HU47S  
httpConnection.setRequestProperty("User-Agent","NetFox"); (p!w`MSv  
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int responseCode=httpConnection.getResponseCode(); 3T)_(SM"  
if(responseCode>=400) 5STk"  
{ {9;x\($&a  
processErrorCode(responseCode); 8}.V[,]6  
return -2; //-2 represent access is error (/e[n.T  
} Lz:Q6  
N;|:Ks#!  
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String sHeader; 557%^)v  
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for(int i=1;;i++) v"8i2+j  
{ EHF dQ0gIa  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0o]T6
  
//Utility.log(in.readLine()); ,: Z7P@  
sHeader=httpConnection.getHeaderFieldKey(i); z:)z]6  
if(sHeader!=null) =
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{ ohlCuH3  
if(sHeader.equals("Content-Length")) QqCwyK0  
{ Z1N=tL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); & oj$h  
break; kj]m@mS[  
} bS&XlgnKi  
} 6|B;C  
else )=Ens=>Z  
break; 6vr8rJ-  
}  BRF4p:  
} @E%fAC  
catch(IOException e){e.printStackTrace ();} Y5R|)x  
catch(Exception e){e.printStackTrace ();} \o<&s{6L  
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Utility.log(nFileLength); :} N;OS_  
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return nFileLength; 4O>0gK{w  
} txFcV  
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6e4A|<  
//保存下载信息（文件指针位置） 39oI &D>8  
private void write_nPos() flS_rY5  
{ =(Pk7{  
try{ Gi Max  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oA`G\Xh_E  
output.writeInt(nStartPos.length); +x)x&;B)/  
for(int i=0;i<nStartPos.length;i++) 3bZ:*6W.6  
{ :IRQouTf:,  
// output.writeLong(nPos); GN=-dLN  
output.writeLong(fileSplitterFetch.nStartPos); ~4=XYYcka  
output.writeLong(fileSplitterFetch.nEndPos); ZL+46fj  
} G4{TJ,~  
output.close(); !HSX:qAP$  
} PmlQW!gfBi  
catch(IOException e){e.printStackTrace ();} 6r}w  
catch(Exception e){e.printStackTrace ();} ?V$@2vBVX4  
} H5/w!y@  
J 7]LMw7  
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//读取保存的下载信息（文件指针位置） #|;;>YnZ  
private void read_nPos() y2:Bv2}  
{ Igb%bO_  
try{ ^^kL.C Ym  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Dy^A??A[E}  
int nCount = input.readInt(); U{ZKxE  
nStartPos = new long[nCount]; }ZkGH}K_}  
nEndPos = new long[nCount]; {9|S,<9  
for(int i=0;i<nStartPos.length;i++) Q'c[yu  
{ /[=U$=uH  
nStartPos = input.readLong(); m?]= =9  
nEndPos = input.readLong(); '=1@,Skj-  
} y7-daek  
input.close(); OJ,Z  
} 4ad-'  
catch(IOException e){e.printStackTrace ();} Tk:%
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catch(Exception e){e.printStackTrace ();} ~NBlJULS  
} #waK^B)<a  
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private void processErrorCode(int nErrorCode) Azag*M?  
{ G[s/M\l  
System.err.println("Error Code : " + nErrorCode); n*y@3.  
} WS2@; 8.N  
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z]n&,q,5g  
//停止文件下载 9B2`FJ  
public void siteStop() s,]z6L0  
{ +9]CGYj  
bStop = true; ;`rz]7,*  
for(int i=0;i<nStartPos.length;i++) jGFDj"Y  
fileSplitterFetch.splitterStop(); jOU1F1  
3 , nr*R!  
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} v\Edf;(  
} P;[>TCs ]8  
//负责部分文件的抓取 AN4(]_]  
**FileSplitterFetch.java Na{&aqdz  
*/ K?H(jP2mpM  
package NetFox; 1SY3  

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import java.io.*;  H;Cv]-  
import java.net.*; }`D-]/T8.  
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public class FileSplitterFetch extends Thread { lCK|PY*  
4<y|SI!  
mcLxX'c6<h  
String sURL; //File URL A}z1~Z+  
long nStartPos; //File Snippet Start Position oPC qv  
long nEndPos; //File Snippet End Position &WHK|bl  
int nThreadID; //Thread's ID  !AFii:#  
boolean bDownOver = false; //Downing is over XDAwE  
boolean bStop = false; //Stop identical MB3 N3,yL  
FileAccessI fileAccessI = null; //File Access interface C.Re*;EI,  
a 8.Xy])!  
[*v-i%U}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nCPIpw,]M  
{ q a}=p  
this.sURL = sURL; pb}4{]sI  
this.nStartPos = nStart; &1M#;rE;D#  
this.nEndPos = nEnd; k{ibD5B  
nThreadID = id; q-4#)EnW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T8\%+3e.  
} #PZBh  
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public void run() D0@d}N  
{ T[]kun  
while(nStartPos < nEndPos && !bStop) m_,j)A%  
{ 9<6Hs3|.!  
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try{ g].v  
URL url = new URL(sURL); .Af H>)E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Q$`3rr  
httpConnection.setRequestProperty("User-Agent","NetFox"); m`H9^w%W  
String sProperty = "bytes="+nStartPos+"-"; QliP9-im3  
httpConnection.setRequestProperty("RANGE",sProperty); XaR(~2  
Utility.log(sProperty); g@IYD  
9}Qrb@DT  
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InputStream input = httpConnection.getInputStream(); IXt cHAgX  
//logResponseHead(httpConnection); UCS`09KNJ  
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byte[] b = new byte[1024]; 4{J'p19  
int nRead; 6HxZS+],c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kJ:zMVN  
{ ;P2(C >|  
nStartPos += fileAccessI.write(b,0,nRead); <]kifiN#  
//if(nThreadID == 1) ?8aPd"x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jG~UyzWH;  
} 2mVLR;s{_  
~ZXAW~a}  
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Utility.log("Thread " + nThreadID + " is over!"); ~n`G>Oe3  
bDownOver = true; \|q.M0  
//nPos = fileAccessI.write (b,0,nRead); W5a>6u=g,  
} TM?7F2
  
catch(Exception e){e.printStackTrace ();} E?3$ *t  
} TM1J1GU  
} N6*v!M+  
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~L=Idt!9  
//打印回应的头信息 jj*e.t:F  
public void logResponseHead(HttpURLConnection con) wO3K2I]>0  
{ /e4#DH  
for(int i=1;;i++) &4-rDR,  
{ 7z4u?>pne*  
String header=con.getHeaderFieldKey(i); 6N]V.;0_5  
if(header!=null) 1[r;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {qkd63X  
Utility.log(header+" : "+con.getHeaderField(header)); o
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else ,Jh('r7  
break; HRZ3}8Qj  
} I\peO/w  
} |? l6S
 
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6 &)fZt  
public void splitterStop() ."\&;:ZNv  
{ =*?2+ ;  
bStop = true; k7ODQ(*v  
} =D6H?K-k!  
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} l\Or.I7n  
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/* 7Vxe]s  
**FileAccess.java {|Pz9a-:  
*//文件访问(定位，写) k1   
package NetFox; M`kR2NCi  
import java.io.*; xr\wOQ*`  
`nDgwp:b"  
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public class FileAccessI implements Serializable{ Z2dy|e(c  
d^<a)>5h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %7oB[2  
RandomAccessFile oSavedFile; y~N,=5>j  
long nPos; }uE8o"q  
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public FileAccessI() throws IOException gB?~!J?  
{ &G>EBKn\2`  
this("",0); ,~_)Cf#CB  
} (]mh}=:KDg  
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public FileAccessI(String sName,long nPos) throws IOException {A2SG#}  
{ n_n0Q}du  
oSavedFile = new RandomAccessFile(sName,"rw"); 0Up@+R
2  
this.nPos = nPos; 5M{DJ/q  
oSavedFile.seek(nPos); Y@S?0  
} 3 9Ql|l$  
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public synchronized int write(byte[] b,int nStart,int nLen) qK4
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{ |Aw(v6  
int n = -1; t/bDDV"  
try{ "b!QE2bRO  
oSavedFile.write(b,nStart,nLen); eYurg6Ob~  
n = nLen; L30x2\C  
} +_?;%PKkuF  
catch(IOException e) PZF>ia}  
{ byv(:xk|'e  
e.printStackTrace (); WG;1[o&  
} ^ZFbp@#U  
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return n; \>j._#t$h  
} buRXzSR  
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} )@3ce'  
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/* 'jeGERMr'  
**SiteInfoBean.java 0gV
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*/ e+=Ojo#  
package NetFox; .bvB8VOrW  
!cLX1S  
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public class SiteInfoBean { S,vrz!'>A  
A5Yfm.Jy  
.*D~ .!  
private String sSiteURL; //Site's URL Tn/ 3`j {  
private String sFilePath; //Saved File's Path ReP7c3D>p  
private String sFileName; //Saved File's Name F5.V
hg  
private int nSplitter; //Count of Splited Downloading File !O)Ruwy  
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public SiteInfoBean() D<}KTyG]  
{//nSplitter的缺省值为5 1bd(JL  
//default value of nSplitter is 5 @6ZQkX/  
this("","","",5); c3!d4mC:  
} Hbx=vLQ6  
a`GoNh,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iO3@2J  
{ sxl29y^*  
sSiteURL= sURL; F)lDK.  
sFilePath = sPath; d/- f]   
sFileName = sName; pF#nj`L  
this.nSplitter = nSpiltter; j,Qp*b#Qo  
WU{G_Fqaz  
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} #+QwRmJdT!  
4'?
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public String getSSiteURL() A"#Gg7]tl'  
{ V;~W,o!  
return sSiteURL; 1>4'YMdZi  
} 1Xt%O86
 
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public void setSSiteURL(String value) X|7gj&1  
{ tV@!jaj\  
sSiteURL = value; 6jiVz%`=Z  
} #)hM]=,e  
=5oE|F%  
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public String getSFilePath() gx#xB8n  
{ &$qqF&  
return sFilePath; X&TTw/J!^  
} 7<mY{!2iF?  
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public void setSFilePath(String value) O2q`2L~  
{ O2us+DhQ  
sFilePath = value; ZTVX5"#Q  
} VjBV2x  
,mhO\P96ik  
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w  
public String getSFileName() =m:xf&r#  
{ <6)Ogv",  
return sFileName; kTT!gZP$  
} _)yn6M'Dt  
Nj5Mc>_   
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public void setSFileName(String value) WOrz7x  
{ 1\=)b< y  
sFileName = value; Waj6.PCFm  
} ']WS@MbJ  
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public int getNSplitter() }KEyJj3"DA  
{ X9K@mX  
return nSplitter; SpU+y|\[0  
} 3s<~}&"  
'X d_8.  
D>|m8-@]  
public void setNSplitter(int nCount) eRKuy l  
{ {`2! 3= "  
nSplitter = nCount; NGcd  
} :hr% 6K7  
} Ua\]]<hj"  
y3{'s>O6  
r:]t9y>$<  
/* HT0VdvLw  
**Utility.java %nk]zf..  
*/ 1G$fU zS  
package NetFox; ``$Dgj[  
E #q gt9  
8[\F*H  
public class Utility { Yj3j?.JJk  
{AUhF}
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mSF>~D1_  
public Utility() g X75zso  
{ X|zQZ<CO  
5Iinen3>  
6<X.]"u+E~  
} `2
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Yef=HSzo  
//线程睡眠 sQUJ]h  
public static void sleep(int nSecond) B( r~Nvc  
{ b* k=
  
try{ 2[!#Xf  
Thread.sleep(nSecond); J<hqF4z  
} OH.^m6Z  
catch(Exception e) $WmB__  
{ UdO(9Jc5^  
e.printStackTrace (); g~EN3~  
} 7QV@lR<C2R  
} 7q\&  
@uA=v/>+  
//日志 %87D(h!.I4  
public static void log(String sMsg) ,w-=8>5lrj  
{ U}f"a!  
System.err.println(sMsg); X 4L"M%i  
} VWhq+8z  
wHx@&Tp  
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public static void log(int sMsg) 7`eg;s^
 
{ (sM$=M<$  
System.err.println(sMsg); p+
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} @yV.Yx"p_  
} X%(1C,C(  
zXX=WH  
^.3(o{g  
/* t =LIkwD  
**TestMethod.java m[aBHA^g  
*/ b'AA*v,b  
package NetFox; ycD.X"  
B`{7-Asc1  
6&oaxAp<s  
public class TestMethod { X|&v]mJ  
q,;8Ka )  
(JMk0H3u  
public TestMethod() !LI 8Xk  
{ ///xx/weblogic60b2_win.exe ,I|3.4z  
try{ N[=c|frho  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~K$dQb])  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Pzt5'O@dA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G^1 5V'*  
fileFetch.start(); F)8M9%g5m  
} =w!>/#U  
catch(Exception e){e.printStackTrace ();} wXR7Ifrv  
=Ju%3ptH0  
:,Zs{\oI3  
} S =5br  
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m=[3"X3W1V  
public static void main(String[] args) "J(T?|t  
{ R6cd;| fan  
new TestMethod(); $G<!+^T  
} } *:H\GL  
} tUGnp'r  
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