http断点续传简单实现（java)

/* "Rs^0iT7>  
**SiteFileFetch.java 9^s sT>&/  
*/ ZwF_hm=/[  
package NetFox; 1rE
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import java.io.*; @eT!v{o  
import java.net.*; %r~TMU2"  
/5r[M=_ihr  
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public class SiteFileFetch extends Thread { 0/(YH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u8
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long[] nStartPos; //开始位置 fX} dh9  
long[] nEndPos; //结束位置 XX}RbE#4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 } "y{d@  
long nFileLength; //文件长度 UmQ 9_H7  
boolean bFirst = true; //是否第一次取文件 KY"W
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boolean bStop = false; //停止标志 I%*o7"  
File tmpFile; //文件下载的临时信息 )Hlr 09t=]  
DataOutputStream output; //输出到文件的输出流 iAWPE`u4  
rMf& HX  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4U>  
public SiteFileFetch(SiteInfoBean bean) throws IOException jPA?0h  
{ NY1olnI  
siteInfoBean = bean; $o1Gxz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bEy j8=P;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <r3F*S=  
if(tmpFile.exists ()) S <|e/![@  
{ @ZK|k  
bFirst = false; XRj<2U5  
read_nPos(); lgA9p 4-  
} ='OPU5(;O  
else a*S4rq@  
{ O&\;BF5:R  
nStartPos = new long[bean.getNSplitter()]; aCFO]  
nEndPos = new long[bean.getNSplitter()]; 0=(5C\w2  
} ?exV:OKLb  
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} ,n~H]66n  
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public void run() pt|u?T_+  
{ ,uEWnZ"4  
//获得文件长度 oe4Fy}Y_;  
//分割文件 UG48g}  
//实例FileSplitterFetch L&'2  
//启动FileSplitterFetch线程 s'fHhG6  
//等待子线程返回 }r*t V)  
try{ 0sk*A0HX-  
if(bFirst) )UZ 's>O  
{ oXV  
nFileLength = getFileSize(); ~n|*-rca  
if(nFileLength == -1) ],&WA?>G  
{ hq$:62NYg  
System.err.println("File Length is not known!"); vQ26U(7\>  
} qeSxE`E"  
else if(nFileLength == -2) I`E9]b(w  
{ >K;p+( <6  
System.err.println("File is not access!"); :%)l*[  
} SAc}5.  
else !}Cd_tj6  
{ oC.:mI  
for(int i=0;i<nStartPos.length;i++) ~0t]`<y=  
{ p^7ZFUP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GZ UDI#  
} ,S}[48$  
for(int i=0;i<nEndPos.length-1;i++) x(5>f9bb  
{ UFm E`|le  
nEndPos = nStartPos[i+1]; &D>e>]E|P  
} |zGwt Z  
nEndPos[nEndPos.length-1] = nFileLength; )DfmO  
} qnv9?Xh  
} C-m OtI  
ft4J.oT  
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//启动子线程 \qi=Us|=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xv9SQ,n<  
for(int i=0;i<nStartPos.length;i++) ;0P2nc:U~  
{ #:w/vk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6}n>Nb;L"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), rM<c;iQ  
nStartPos,nEndPos,i); $2 ~RZpS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `8KWZi4 ]  
fileSplitterFetch.start(); )#9/vIQ  
} b,$H!V*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #ZRQVC;b;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QOcB ]G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G?8LYg!-  
nEndPos = " + nFileLength); ePa1 @
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// fileSplitterFetch[nPos.length-1].start(); \ :1MM  
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ShxB!/s  
//等待子线程结束 t+W+f  
//int count = 0; 3 =KfNz_  
//是否结束while循环 q[] "`?  
boolean breakWhile = false; $j)Er.!9|R  
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while(!bStop) smF#'"{  
{ |Xlc2?e  
write_nPos(); 8sx\b  
Utility.sleep(500); P'KaWu9z  
breakWhile = true; (SfP3  
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wtndXhVC4>  
for(int i=0;i<nStartPos.length;i++) \3hhM}6)DM  
{ [58xT>5`m  
if(!fileSplitterFetch.bDownOver) 5 b( [1*  
{ \vs,$h  
breakWhile = false; L8Z[Ly+_  
break; 1%G<gbHpI  
} /KO!s,Nk  
} s{2BG9s
 
if(breakWhile) WhMr'l/e  
break; #^"\WG7{  
-:Nowb  
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//count++; u7UqN  
//if(count>4) pj6Q0h)  
// siteStop(); @AvXBMq|  
} xYtY}?!"  
&G@(f=  
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System.err.println("文件下载结束！"); @ZK#Y){  
} cm
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catch(Exception e){e.printStackTrace ();} R)?K+
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} ja$e)  
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//获得文件长度 MGCwT@P  
public long getFileSize() ^VR1whCrx  
{ _Z~wpO}/  
int nFileLength = -1; f9cS^v_:  
try{ R|Z$aHQ  
URL url = new URL(siteInfoBean.getSSiteURL()); wc
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CeNpJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); .taJCE  
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int responseCode=httpConnection.getResponseCode(); LS{g=3P0  
if(responseCode>=400) ~Us1F=i_Q  
{ |xG|HJm,  
processErrorCode(responseCode); Uq 2Uv  
return -2; //-2 represent access is error Is` S  
} ^)m]j`}IGb  
@#c(4}^ <w  
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String sHeader; 4xuL{z;\  
!bFa\6]q  
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for(int i=1;;i++) 2-ev7:  
{ c@1C|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xG 7;Ps4L  
//Utility.log(in.readLine()); YES!?^}  
sHeader=httpConnection.getHeaderFieldKey(i); m0t5oO  
if(sHeader!=null) %f\ M61Z  
{ 2lDgvug  
if(sHeader.equals("Content-Length")) j01.`G7Q  
{ KW+ps16~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xw!eB?A  
break; Z'6 o$Xv  
} #\"8sY,j  
} v)N8vFdd  
else >V;JI;[  
break; XtRfzqg?K  
} M@UkXA
}  
} :Qh5ZO&G0  
catch(IOException e){e.printStackTrace ();} yHLclv  
catch(Exception e){e.printStackTrace ();} >P/kb fPA  
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Utility.log(nFileLength); 0PE $n  
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return nFileLength; P1]ucu_y,  
} -q[T0^eS  
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;XSRG*3j~4  
//保存下载信息（文件指针位置） _SjS^z~  
private void write_nPos() ?|Fu^eR%X  
{ "tBdz V  
try{ 2GLq#")P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &_HSrU  
output.writeInt(nStartPos.length); W}EI gVHs  
for(int i=0;i<nStartPos.length;i++) #M&rmKv)g  
{ @g(N!n~  
// output.writeLong(nPos);  HUr;ysw  
output.writeLong(fileSplitterFetch.nStartPos); .!RBhLH_g  
output.writeLong(fileSplitterFetch.nEndPos); PA5ET@mD  
} I>k3X~cG  
output.close(); 8s-RNA>7^  
} u{"o*udU  
catch(IOException e){e.printStackTrace ();} S;M'qw
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catch(Exception e){e.printStackTrace ();} N*$<K
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} x~!B.4gT2  
]|<PV5SY3.  
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//读取保存的下载信息（文件指针位置） J4 .C"v0a  
private void read_nPos() C_dsYuQ5R  
{ ~;_]U[eOL  
try{ zLc.4k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1GN>,Lb:o  
int nCount = input.readInt(); Y}7'OM  
nStartPos = new long[nCount]; LN ]ks)  
nEndPos = new long[nCount]; +2O('}t  
for(int i=0;i<nStartPos.length;i++) ag]b]K  
{ p<Wb^BE  
nStartPos = input.readLong(); xY(+[T!OF  
nEndPos = input.readLong(); " E72j.  
} 5s8S;Pb]<  
input.close(); 3hab51J  
} (l{+T#  
catch(IOException e){e.printStackTrace ();} 54WM*FZ  
catch(Exception e){e.printStackTrace ();} 8jd<|nYnfc  
} KGxF3xS*7  
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91r9RG>  
private void processErrorCode(int nErrorCode) VQU[5C  
{ C6,GgDH`  
System.err.println("Error Code : " + nErrorCode); LO[1xE9  
} eW"i'\`0  
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lAJ)  
//停止文件下载  ^ 'FC.  
public void siteStop() Zq~2BeB  
{ ~f
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bStop = true; s0H_Y'  
for(int i=0;i<nStartPos.length;i++) ~QFD ^SoK  
fileSplitterFetch.splitterStop(); C$){H"#  
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/|t vGC.#  
} 0bQaXxt|p  
} Vo+d3  
//负责部分文件的抓取 {S%)GvrT  
**FileSplitterFetch.java yT`[9u,  
*/ /%po@Pm#I  
package NetFox; Wy@Z)z?  
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bxyEn'vNvQ  
import java.io.*; #pBAGm3  
import java.net.*; @g9j+DcU  
#bUWF|zfT  
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public class FileSplitterFetch extends Thread { :^0g}8$<  
y$r^UjJEO  
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String sURL; //File URL Q-F'-@`(C  
long nStartPos; //File Snippet Start Position aO.'(kk8  
long nEndPos; //File Snippet End Position ;!, ]}2w*X  
int nThreadID; //Thread's ID /O|!Sg{  
boolean bDownOver = false; //Downing is over r(yJE1Wz  
boolean bStop = false; //Stop identical (M4~N)7<P5  
FileAccessI fileAccessI = null; //File Access interface >C+0LF`U  
*h1Zqb  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LeO ))  
{ WLiY:X(+|  
this.sURL = sURL; @I\Z2-J  
this.nStartPos = nStart; bv9\Jp0c  
this.nEndPos = nEnd; J9)wt ?%j  
nThreadID = id; =vT3SY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n} GIf&  
} :>nk63
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public void run() Fly@"W4a  
{ '&Q_5\Tn  
while(nStartPos < nEndPos && !bStop) g,Kb9['  
{ ZB:Fjq  
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$JqdI/
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try{ ~53E)ilB  
URL url = new URL(sURL); Vm'ReH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~ i1w,;(  
httpConnection.setRequestProperty("User-Agent","NetFox"); l"}W $3]u$  
String sProperty = "bytes="+nStartPos+"-"; M$FXDyr  
httpConnection.setRequestProperty("RANGE",sProperty); vxUJ4|Qz  
Utility.log(sProperty); {-^>) iJqt  
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InputStream input = httpConnection.getInputStream(); *0i   
//logResponseHead(httpConnection); 4v3
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byte[] b = new byte[1024]; -yg9ug  
int nRead; _E)x
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \9Itu(<f  
{ C+P}R]cT"  
nStartPos += fileAccessI.write(b,0,nRead); VPys  
//if(nThreadID == 1) ZgtW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $LAaG65V  
} 2c5>0f  
T=VVK6Lc:  
)jR:\fe  
Utility.log("Thread " + nThreadID + " is over!"); vMzR3@4e  
bDownOver = true; & ?/h5<  
//nPos = fileAccessI.write (b,0,nRead); WaWT 5|A  
} { YJ.BWr  
catch(Exception e){e.printStackTrace ();} zVxiCyU  
} _M:)x0("  
} tFwQ /  
\b.2f+;3  
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//打印回应的头信息 A&$!s)8z  
public void logResponseHead(HttpURLConnection con) L]9!
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{ m4E 6L  
for(int i=1;;i++) hrZ~7 0r  
{ <$UMMA  
String header=con.getHeaderFieldKey(i); b$PNZC8f  
if(header!=null) Y4@~NCU/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F5:*;E;$  
Utility.log(header+" : "+con.getHeaderField(header)); (d^pYPr{  
else ~S|Vd  
break; #$jAGt3^BT  
} [+{ ot   
} s7FqE>#c0  
n+zXt?{u  
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public void splitterStop() +/\.%S/  
{ 5tP0dQYd
 
bStop = true; `U2PlCf|  
} /nb(F h|{T  
3(^9K2.s}  
lxbbyy25  
} PwF}yxkI  
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b44H2A.  
/* >P\Tnb"Q\  
**FileAccess.java 70HEu@-  
*//文件访问(定位，写) }xLwv=Ia  
package NetFox; *}
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import java.io.*; "^_p>C)T  
*sAoYx  
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public class FileAccessI implements Serializable{ }5Y.N7F  
&`@,mUi{Ac  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !!2~lG<]  
RandomAccessFile oSavedFile; +R2
 
long nPos; EoQ.d|:g  
of+$TKQNpN  
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public FileAccessI() throws IOException 5? c4aAn  
{ &\0LR?Nh  
this("",0); HP]Xh~aP  
} UY}lJHp0  
qf)
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public FileAccessI(String sName,long nPos) throws IOException N_C\L2  
{ \hi{r@
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oSavedFile = new RandomAccessFile(sName,"rw"); v{JCEb&wN  
this.nPos = nPos; .]r[0U  
oSavedFile.seek(nPos); _ esFx  
} aMv  
sB7DF<91  
D3XQ>T[*q  
public synchronized int write(byte[] b,int nStart,int nLen) -.^Mt.)  
{ %NeKDE  
int n = -1; !Toq~,a8?  
try{ Fi7pq2  
oSavedFile.write(b,nStart,nLen); ,{'~J @  
n = nLen; ^4s#nf:}  
} ?[XH`c,  
catch(IOException e) -|f9~(t  
{ HkEp}R  
e.printStackTrace (); vf5[x!4  
} "<!|am(  
rB=1*.}FLc  
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return n; AqN(htGvx  
} F>^k<E?,C  
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} s)]|zu0"Ku  
5n(p1OM2q  
_BR>- :Jr  
/* s?0r\cc|:  
**SiteInfoBean.java QQC0uta`  
*/
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package NetFox; "G`)x+<~Z8  
vtL)  
)}paQmy#  
public class SiteInfoBean { >Pv%E  
dZnq 96<:|  
^GRd;v=-@  
private String sSiteURL; //Site's URL uidE/7  
private String sFilePath; //Saved File's Path 6GJ?rE E/  
private String sFileName; //Saved File's Name z#,?*v  
private int nSplitter; //Count of Splited Downloading File yGS._;#R  

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bZ3CJ f&mE  
public SiteInfoBean() |$1j;#h  
{//nSplitter的缺省值为5 #wC4$y<>  
//default value of nSplitter is 5 H2k>E}`  
this("","","",5); !_x-aro3<  
} xss D2*l  
apw8wL2  
-O(.J'=8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DK4V/>@8  
{ xhimRi  
sSiteURL= sURL; F'SOl*v(s5  
sFilePath = sPath; Yt|{l  
sFileName = sName; v{%2`_c  
this.nSplitter = nSpiltter; kP[ Y  
4AP<mo  
:=~([oSNW"  
} /jS  
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{BKI8vy  
public String getSSiteURL() J+z0,N[  
{ qPzgGbmD9  
return sSiteURL; *B3` #t  
} JNMZn/  
[8
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public void setSSiteURL(String value) b,SY(Ce~g  
{ C/]0jAAE7  
sSiteURL = value; W}T+8+RU  
}  wl9E  
8.9S91]=  
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public String getSFilePath() Gia_B6*Y[  
{ oq0G@  
return sFilePath; 0eUsvzz15  
} B}*xrPj  
}1(F~6RH  
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public void setSFilePath(String value) 6.K)uQgjmv  
{ vk[Km[(U'  
sFilePath = value; 1}V_:~7  
} #]:nQ(  
4'X^YBm  
s6KZV@1  
public String getSFileName() iCw~4KG  
{ m\jp$  
return sFileName; *4r;H2%c  
} N^`F_R1Z  
{){i ONd  
~BZA_w"`1  
public void setSFileName(String value) m3,]j\  
{ A:;KU  
sFileName = value; u^:!!Suo  
} $Cf_RFH0  
uWMAXGL  
4'_uN$${$  
public int getNSplitter() se(_`a/4Q  
{ 4}?Yp e-  
return nSplitter; A u(Ngq  
} !xa,[$w(^  
v?Y9z!M  
+gT?{;3[i  
public void setNSplitter(int nCount) - d>)  
{ BH%eu 7`t  
nSplitter = nCount; tR2IjvmsX  
} Q*U$i#,  
} JY%c<  
W~DY-;  
yNI}=Z  
/* xJZbax[  
**Utility.java x~
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*/ ^WM)UZEBC  
package NetFox; h4.ZR={E  
?M\3n5;  
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public class Utility { LI(Wu6*Y  
Yo:>m*31  

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public Utility()  H\)on"  
{ Ym0Xl(Se  
6K*7%8Y/G  
{)jQbAr(G  
} tQUp1i{j\  
G~YV6??  
//线程睡眠 HH[?LKd<  
public static void sleep(int nSecond) 3pq&TYQU  
{ >mh:OJH45  
try{ T
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Thread.sleep(nSecond); 7eh}Je8  
} QbS w<V  
catch(Exception e) S{J$[!F  
{ %.<w8ag  
e.printStackTrace (); 3!ulBiMh  
} eK3J9;X  
} !XgkK k  
hv7!x=?8  
//日志 1LcQ*d  
public static void log(String sMsg) ggX'`bK  
{ 9<-AukK m  
System.err.println(sMsg); tjO||]I  
} dkRJ^~  
*crpM3fO>  
30[?XVI&  
public static void log(int sMsg) H VG'v>s@  
{ KqaeRs.u  
System.err.println(sMsg); aoMQ_@0  
} RI cA)I.  
} zneK)C8&q3  
P1H`NOC  
7kG>s9O  
/* `<+D<x)(3  
**TestMethod.java hwkol W  
*/ H}JH339  
package NetFox; Gl}=Q7  
js7J#b7  
CWt,c
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public class TestMethod { UZ&bT'>;9g  
E jBEZL|_  
mKWA-h+f  
public TestMethod() g8}/Ln*W'  
{ ///xx/weblogic60b2_win.exe qFf'RgUtP  
try{ TZPWMCN4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8|V6RgA%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Jp_{PR:&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D='/-3f!F]  
fileFetch.start(); --.:eFE/  
} M
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catch(Exception e){e.printStackTrace ();} Q_LPLmM  
IN`05Q  
hGD7/qTN  
} ':F{st>&H  
*1}9`$  
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public static void main(String[] args) uXu'I  
{ $
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new TestMethod(); (!{_O_&  
} /gXli)  
} QoI@/ jLj  
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