http断点续传简单实现（java)

/* N;)Y+amg^  
**SiteFileFetch.java hX?rIx  
*/ "ZuhN(-`  
package NetFox; v&.`^O3W  
import java.io.*; >O7ITy  
import java.net.*; IYJS>G%*  
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public class SiteFileFetch extends Thread { C&d%S|:IR  
\dIc_6/D1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean OI=LuWGQE1  
long[] nStartPos; //开始位置 7.-g=R
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long[] nEndPos; //结束位置 ZjlFr(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cy0 %tsB|  
long nFileLength; //文件长度 \ow3_^Bk  
boolean bFirst = true; //是否第一次取文件 u9d4zR  
boolean bStop = false; //停止标志 bo;;\>k  
File tmpFile; //文件下载的临时信息 Cd>GY  
DataOutputStream output; //输出到文件的输出流 x2 s%qZ#  
1-HL#y*7$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }]8n3&*  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2!6+>nvO  
{ 0zSRk]i.f  
siteInfoBean = bean; dr25;L? B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 35 Y#eU2]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \t'v-x>2y5  
if(tmpFile.exists ()) )p,uZ`~
v  
{ *6Ojv- G|5  
bFirst = false; bp'qrcFuiL  
read_nPos(); (WW*yv.J  
} >g):xi3qK  
else +Lq;0tRC  
{ :'\4%D=w  
nStartPos = new long[bean.getNSplitter()]; x2P}8Idg?A  
nEndPos = new long[bean.getNSplitter()]; 3' Ht
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} {I/|7b>@r  
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} L&C<-BA/  
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public void run() --ED]S 8  
{ 5&
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//获得文件长度 $On  
//分割文件 /}_OCuJJ,  
//实例FileSplitterFetch %?o@YwBo^E  
//启动FileSplitterFetch线程 $_
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//等待子线程返回 R@h@@lSf  
try{ IW48Sg  
if(bFirst) "E? 8.`T  
{ Z0f0tL&A<  
nFileLength = getFileSize(); >a5M:s)  
if(nFileLength == -1) >e]46K  
{ iQrT
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System.err.println("File Length is not known!"); r_sZw@lqJ  
} *O`76+iZ|_  
else if(nFileLength == -2) ?;\xeFy!  
{ (-lu#hJ`&r  
System.err.println("File is not access!"); N8$MAW  
} /xK5%cE>B  
else c|f)k:Q  
{ nm[ yp3B  
for(int i=0;i<nStartPos.length;i++) k+(UpO=/*  
{ S Z@ JzOA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "82<}D^;  
} wm3fd7T  
for(int i=0;i<nEndPos.length-1;i++) AR<'Airi:  
{ "IOu$?  
nEndPos = nStartPos[i+1]; j( *;W}*^  
} z0@)@4z!  
nEndPos[nEndPos.length-1] = nFileLength; In-W,   
} V;b^b5yZ>  
} _g%Wx?K9  
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//启动子线程 ^':Az6Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \M]w I  
for(int i=0;i<nStartPos.length;i++) rcc.FS  
{ !PCw-&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =~Ac=j!q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <lk_]+ XJ3  
nStartPos,nEndPos,i); rUunf'w`e1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qXHr"  
fileSplitterFetch.start(); $(2c0S{1  
} s+"[S%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *^'$YVd#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _$OhV#LKG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #}^kMD >  
nEndPos = " + nFileLength); Y(>]7  
// fileSplitterFetch[nPos.length-1].start(); 3I)!.N[m  
G\ twx ;  
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//等待子线程结束 !ul)e;a  
//int count = 0; Sb&sW?M  
//是否结束while循环 xg'FC/1LD  
boolean breakWhile = false; M2[ywab  
b";w\H  
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while(!bStop) 4|+6a6  
{ .x__X3P>\  
write_nPos(); l}>gG[q!  
Utility.sleep(500); /2,s-^  
breakWhile = true; sje}E+{[  
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for(int i=0;i<nStartPos.length;i++) 3r=IO#  
{ cmQLkT"#K  
if(!fileSplitterFetch.bDownOver) 9R
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{ w%,Iy,G@  
breakWhile = false; 05".;(  
break; (7nWv43  
} &A=q_  
} Qtmsk:qm  
if(breakWhile) ~%Y*2i f  
break; _7SOl.5ZE  
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8-cB0F=j_  
//count++; a#X[V5|6Q  
//if(count>4) s[:e '#^  
// siteStop(); -\;x>=#B  
} e![|-m%  
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System.err.println("文件下载结束！"); f"h{se8C  
} a;p3M
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catch(Exception e){e.printStackTrace ();} F+vgkqs@9  
} HYgq@47$[  
A"S{W^iL  
%YhZ#>WT  
//获得文件长度 dMsX}=EI<  
public long getFileSize() A7.$soI\  
{ 3@e#E4+ff  
int nFileLength = -1; !+T9NqDv[  
try{ WU-.lg'c'  
URL url = new URL(siteInfoBean.getSSiteURL()); kV7c\|N9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &3VR)Bxn  
httpConnection.setRequestProperty("User-Agent","NetFox"); H*_:IfI!  
#uNQ+US0  
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int responseCode=httpConnection.getResponseCode(); }Vw"7  
if(responseCode>=400) 4/S% eZB  
{ ya]CxnKR3  
processErrorCode(responseCode); }q-_|(b;  
return -2; //-2 represent access is error  WpX)[au  
} tP2hU[7Z  
>Pv#)qtm  
#RoGyrLo  
String sHeader; rlYAy5&  
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for(int i=1;;i++) l]whL1N3  
{ TD+V.}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2<Pi2s'  
//Utility.log(in.readLine()); fZ6lnZ  
sHeader=httpConnection.getHeaderFieldKey(i); tk4~ 8  
if(sHeader!=null) yG?,8!/]  
{ /jih;J|  
if(sHeader.equals("Content-Length")) #SQao;>  
{ 4os7tx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wa~'p+<c~b  
break; pR2QS
 
} E1:{5F5/  
} b,YTw  
else /N+*=LIK I  
break; ]Y;EIn  
} \R45#. P6X  
} 6sb,*uSn%  
catch(IOException e){e.printStackTrace ();} `,ZsKxI  
catch(Exception e){e.printStackTrace ();} M xUj7ae  
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Utility.log(nFileLength); ?4wS/_C/
 
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return nFileLength; %fMK^H8{  
} hA6!F#1  
uJ,>Y# ?  
F+R4nFA  
//保存下载信息（文件指针位置） Oqeoh<y!\  
private void write_nPos() bLoAtI  
{ agX-V{l.  
try{ $x]'6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >=c<6#:s<9  
output.writeInt(nStartPos.length); g7@G&Ro9J\  
for(int i=0;i<nStartPos.length;i++) Cul^b_UmP#  
{ 6=2M[T  
// output.writeLong(nPos); wwVK15t  
output.writeLong(fileSplitterFetch.nStartPos); } pE<P;\]k  
output.writeLong(fileSplitterFetch.nEndPos); #/t^?$8\\  
} Pq`]^^=be'  
output.close(); s=Pwkte  
} $-Q,@Bztq  
catch(IOException e){e.printStackTrace ();}  q%,q"WU  
catch(Exception e){e.printStackTrace ();} 0EfM~u  
} ,g%2-#L%  
wI\v5&X-B  
8C4DOz|  
//读取保存的下载信息（文件指针位置） E$m3Gg)s>N  
private void read_nPos() FQ>KbZ
h  
{ qczGv2%!  
try{ 'E+Ty(ED5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TYW$=p|  
int nCount = input.readInt(); W!4(EdT*Cq  
nStartPos = new long[nCount]; ; k{w@L.@  
nEndPos = new long[nCount]; TTpK8cC  
for(int i=0;i<nStartPos.length;i++) #R<4K0Xan  
{ zbZ0BD7e  
nStartPos = input.readLong(); \D>vdn"Lx  
nEndPos = input.readLong(); l)GV&V  
} g@hg u  
input.close(); Az
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} !vHUe*1a{  
catch(IOException e){e.printStackTrace ();} ?e9Acc`G5  
catch(Exception e){e.printStackTrace ();} 1 *'SP6g  
} vtG_A{l  
 )]L:OE  
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private void processErrorCode(int nErrorCode) Ej>5PXp'2  
{ +[Nc";Oy  
System.err.println("Error Code : " + nErrorCode); v|`f8M2  
} AB40WCu]*  
6j@3C`Yd  
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//停止文件下载 F)g.CDQ!c  
public void siteStop() 4-z3+e  
{ Bh?K_{
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bStop = true; i6M_Gk}  
for(int i=0;i<nStartPos.length;i++) Au,xIe!t
 
fileSplitterFetch.splitterStop(); j@$p(P$  
cx M=#Go  
$]EG|]"Ns  
} 6f/>o
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} V|xKvH  
//负责部分文件的抓取 Q-fi(UP  
**FileSplitterFetch.java _3-nw  
*/ V6Ie\+@.\  
package NetFox; 1?sR1du,  
hK*:pf  
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import java.io.*; 1\t}pGSOeh  
import java.net.*; O0Y/y2d  
E$]7w4,n  
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public class FileSplitterFetch extends Thread { We%-?l:"  
Q.Uyl:^PxU  
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String sURL; //File URL DZKVZ_q  
long nStartPos; //File Snippet Start Position i&\N_PUm[  
long nEndPos; //File Snippet End Position 5fuOl-M0W  
int nThreadID; //Thread's ID .dwb@$  
boolean bDownOver = false; //Downing is over 6T0[ ~@g5  
boolean bStop = false; //Stop identical 9MA/nybI  
FileAccessI fileAccessI = null; //File Access interface *&{M,  
eU?SLIof[{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .q#2 op  
{ hGyi@0  
this.sURL = sURL; T<kyxbjR  
this.nStartPos = nStart; JTB
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this.nEndPos = nEnd; )]~'zOE_  
nThreadID = id; m,',luQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j/_@~MJBt  
} =FUORj\O  
i{TErJ{}e  
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public void run() s,>1n0a  
{ -I4-K%%B`  
while(nStartPos < nEndPos && !bStop) LyRto  
{ &g;4;)p*8  
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try{ 6n37R#(  
URL url = new URL(sURL); ~]8bTw@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nV'~uu  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1^rODfY0  
String sProperty = "bytes="+nStartPos+"-"; z 3)pvX5  
httpConnection.setRequestProperty("RANGE",sProperty); ?zp@HSa9  
Utility.log(sProperty); xo/[,rR  
:c%vl$  
//*>p  
InputStream input = httpConnection.getInputStream(); C*Avu  
//logResponseHead(httpConnection); ~jMdM~}  
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byte[] b = new byte[1024]; 'zV/4iE=  
int nRead; r168ft?c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |Z}uN!Jm  
{ LQ pUyqR  
nStartPos += fileAccessI.write(b,0,nRead); *+TIF"|1  
//if(nThreadID == 1) U&#1qRm\h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +*-u_L\'  
} Q?rb(u(  
x"0*U9f  
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Utility.log("Thread " + nThreadID + " is over!"); w.exLC  
bDownOver = true; v{9< ATi  
//nPos = fileAccessI.write (b,0,nRead); M?pu7wa  
} '}h[*IB}5  
catch(Exception e){e.printStackTrace ();} qg?O+-+  
} Fn0Rq9/@  
} )? WiO}"  
OLpE0gZ.|`  
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//打印回应的头信息 ?h4-D:!$L  
public void logResponseHead(HttpURLConnection con) Pda(O;aNU  
{ &A>Hq/Y  
for(int i=1;;i++) Y0iL+=[k`m  
{ UV8,SSDTV  
String header=con.getHeaderFieldKey(i); l9 RjxO.~U  
if(header!=null) Z=`\U?,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 44_7gOZ  
Utility.log(header+" : "+con.getHeaderField(header)); xh Sp<|X_  
else vG9A'R'P  
break; ,W"Q)cL  
} uTY5.8  
} Y%OE1F$6NN  
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public void splitterStop() odAeBQy  
{ QU0K'4Yx5j  
bStop = true; GGHe{l  
} n)$T zND  
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} KZ^W@*`D  
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/* hKP!;R  
**FileAccess.java 2lPj%i 5  
*//文件访问(定位，写) :{NvBxc[  
package NetFox; Z"rrbN1  
import java.io.*; Xi3:Ok6FZ  
Ht#5;c2/  
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public class FileAccessI implements Serializable{ `ro~l_U;A  
~ldqg2c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yvQRr75
  
RandomAccessFile oSavedFile; 12D>~#J  
long nPos; !Zr 9
t|_  
@X$~{Vp__  
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public FileAccessI() throws IOException "[Z'n9C  
{ '@jP$6T&  
this("",0); a9+l:c@  
} v;%>F)I  
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public FileAccessI(String sName,long nPos) throws IOException 5{`a\;*  
{ <k41j=d  
oSavedFile = new RandomAccessFile(sName,"rw"); Ct8}jg
"  
this.nPos = nPos; *$+:Cbe-F  
oSavedFile.seek(nPos); ><l|&&e-  
} ;J]
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public synchronized int write(byte[] b,int nStart,int nLen) kMCgfL  
{ vXq2="+  
int n = -1; +dw=
)A#/  
try{ 2^V/>|W>w  
oSavedFile.write(b,nStart,nLen); I(bxCiRV  
n = nLen; `vMrlKq  
} "8BZj;yS  
catch(IOException e) jDyG~de  
{ UWf@(8  
e.printStackTrace (); NFAjh?#  
} $,s"c(pv[,  
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return n; l-~ o&n  
} #9's
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} x/)o'#d$|l  
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/* Z(~v{c %<  
**SiteInfoBean.java dPVl\<L1  
*/ HZ_,f"22  
package NetFox; M%aA1!@/  
E U# M.  
GIs *;ps7w  
public class SiteInfoBean { mO?yrM *  
saPg2N,  
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private String sSiteURL; //Site's URL @i9eH8lT  
private String sFilePath; //Saved File's Path 8-"lK7  
private String sFileName; //Saved File's Name 1OwVb  
private int nSplitter; //Count of Splited Downloading File &3_S+.JO  
^! r<-J  
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public SiteInfoBean() W "}Cfv  
{//nSplitter的缺省值为5 ?h1r6?Sug{  
//default value of nSplitter is 5 H[;\[3  
this("","","",5); m})EYs1  
} @D3|Ak1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1>"Yw|F-|3  
{ aj\ zc I  
sSiteURL= sURL; Wh7}G   
sFilePath = sPath; Y}aaW[  
sFileName = sName; &4 ~C%{H3  
this.nSplitter = nSpiltter; .!><qVg  
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=D}]
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} (&=gM  
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public String getSSiteURL() V']{n7a-  
{ J Gpy$T{t  
return sSiteURL; Eg/=VBtc  
} '(.vB~m7*+  
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public void setSSiteURL(String value) {] Zet}2  
{ % a9C]?  
sSiteURL = value; Mu>WS)1lS  
} 
2 yY.rs  
0;6^fiSY;  
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public String getSFilePath() aEJds}eE6)  
{ >ow5aOlQ&  
return sFilePath; K3xs=q]:@  
} e ab_"W   
2(%C  
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public void setSFilePath(String value) Xv2u7T\  
{ Lfj]Y~*z  
sFilePath = value; Ic,V,#my  
} O.+02C_*  
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public String getSFileName() -$0w-M8'  
{ Z'ZN^j{  
return sFileName; _go1gf7  
} 9[7Gxmf  
8<w8"B.i  
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public void setSFileName(String value) >i:hdcxe  
{ G|,'6|$jE  
sFileName = value; F/(z3Kf  
} <lxE^M  
c7[+gc5}  
JS:AHJSz  
public int getNSplitter() X7~AqG  
{ _+?v'#  
return nSplitter; Qjl.O HO  
} ]DV=/RpJ9B  
+:#x!i;W8[  
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public void setNSplitter(int nCount) D)my@W0,  
{ QaAWO  
nSplitter = nCount; 'nR'o /!  
} "7RnT3  
} .V.x0  
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/* wFHbz9|@I  
**Utility.java #y4+O;{  
*/ Ki_8
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package NetFox; cf7UV6D g  
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<`/22S"  
public class Utility { j1Q"s(  
^]A,Q%1q^  
$^XCI%DH  
public Utility() {G^f/%  
{ 3%'Y):  
&|8R4l
C|  
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} c|,6(4j>$  
rgOc+[X  
//线程睡眠 [fjP.kw;J  
public static void sleep(int nSecond) ( ;(DI^Un8  
{ Tz"Xm/Gy  
try{ x_K8Gr#Z0  
Thread.sleep(nSecond); '9R.$,N  
} 4{Q{>S*h  
catch(Exception e) ivb?B,Lz0  
{ K>a+-QWK3  
e.printStackTrace (); "{igrl8  
} \dzHG/e  
} =8!FY"c*  
+YA,HhX9  
//日志 zP(UaSXz/  
public static void log(String sMsg) d2!A32m  
{ B{^ojV;]m  
System.err.println(sMsg); G7yR&x^  
} e71dNL'$  
bWe_<'N  
m\];.Da  
public static void log(int sMsg) ~t` uq  
{ -T0@b8  
System.err.println(sMsg); 4U1!SR]s  
} `YinhO:Z  
} OlwORtWzZ  
|sIr}}  
f#mcWL1}  
/* u#c3T'E  
**TestMethod.java (> {CwtH][  
*/ (Q/Kp*a  
package NetFox; $0OWPC1  
ER ^#J**  
[|)Eyd[G  
public class TestMethod { q#n0!5Lv2  

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# {'1\@q
 
public TestMethod() n=+K$R  
{ ///xx/weblogic60b2_win.exe U fzA/  
try{ `]q>A']Dl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hj_%'kk-A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 13X\PO'9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l^$8;$Rq  
fileFetch.start(); PI5a'k0F  
} \~O}V~wE  
catch(Exception e){e.printStackTrace ();} AdWLab;  
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7Y?=ijXXx\  
} 3S97hn{|=  
 >>n
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public static void main(String[] args) Gd]!D~[1  
{ x^J}]5{0  
new TestMethod(); |1@/gqa  
} l?AWG&  
} 1$]hyC/f  
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