http断点续传简单实现（java)

/* r<4FF=  
**SiteFileFetch.java 9qxB/5d_  
*/ %|md0  
package NetFox; 3uA%1 E  
import java.io.*; .zf#S0y%(  
import java.net.*; aV3:wp]Gn  
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r  
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public class SiteFileFetch extends Thread { iW\cLp "  
<}x_F)E[t  
@#[<5ld  
SiteInfoBean siteInfoBean = null; //文件信息Bean tpp.
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long[] nStartPos; //开始位置 =9@{U2 =l  
long[] nEndPos; //结束位置 !}fq%8"-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t>;u;XY!;  
long nFileLength; //文件长度 >-fOkOWXy  
boolean bFirst = true; //是否第一次取文件 "i/ l'  
boolean bStop = false; //停止标志 7,U^v}$  
File tmpFile; //文件下载的临时信息 z45 7
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DataOutputStream output; //输出到文件的输出流 :db:|=#T  
u'}SaX]0  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m3zmyw}  
public SiteFileFetch(SiteInfoBean bean) throws IOException CC,_I>t  
{ :^".cs?g  
siteInfoBean = bean; luD.3&0n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W.b?MPy]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b,U"N-6  
if(tmpFile.exists ()) ./nq*4=  
{ QV/o;  
bFirst = false; WO{V,<;  
read_nPos(); hd*bPj;  
} Cisv**9  
else $oKT-G  
{ Z
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nStartPos = new long[bean.getNSplitter()]; [>l
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nEndPos = new long[bean.getNSplitter()]; QTX5F5w  
} w~EBm=v_>  
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} CjRI!}S  
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public void run() tNf?pV77  
{ f S-(Kmh  
//获得文件长度 >D20f<w(H  
//分割文件 $|~YXH~O  
//实例FileSplitterFetch f?)BAah  
//启动FileSplitterFetch线程 y>}dKbCN  
//等待子线程返回 S !Dq8  
try{ ,n&@O,XGy  
if(bFirst) D{1k{/cF  
{ Z6@W)QX  
nFileLength = getFileSize(); 'r_{T=  
if(nFileLength == -1) O/EI8Qvm  
{ IK~'ke  
System.err.println("File Length is not known!"); -olD!zKS  
} oCD#Gmr  
else if(nFileLength == -2) `uL^!-  
{ ~Y=v@] 2/  
System.err.println("File is not access!"); ];cJIa  
} + ;u<tA  
else )+ }\NCFh  
{ D*!p8J8Ku  
for(int i=0;i<nStartPos.length;i++) ^~iu),gu  
{ .{,
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); yTj!(C  
} .Y!]{c  
for(int i=0;i<nEndPos.length-1;i++) p'PHBb8I  
{ aH6{_eY  
nEndPos = nStartPos[i+1]; ]ADj9  
} Y![m'q}K  
nEndPos[nEndPos.length-1] = nFileLength; d8l T+MS=  
} $ {29[hO  
} |ymw
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t[>y=89
 
//启动子线程 1+`Bli]dE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fZM)>  
for(int i=0;i<nStartPos.length;i++) |l5ol@2*  
{ QU0FeGtz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]&l.-0jt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J=QuZwt  
nStartPos,nEndPos,i); 2M`]nAk2a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?LE\pk R  
fileSplitterFetch.start(); %6-5hBzZN  
} b|7c]l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~loJYq'y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {Dv^j#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5LJUD>f9Z  
nEndPos = " + nFileLength); L< 3U)Gp  
// fileSplitterFetch[nPos.length-1].start(); =3KK/[2M  
.9r+LA{  
;IklS*p]  
//等待子线程结束 V5
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//int count = 0; <HReh>)[  
//是否结束while循环 jSLC L'  
boolean breakWhile = false; y*i_Ec\h  
Ln~Z_!  
GTvp)^h  
while(!bStop) ]`[r=cG  
{ RZwjc<T  
write_nPos(); *dB^B5  
Utility.sleep(500); Wz}DC7  
breakWhile = true; Dw\)!,,i7U  
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for(int i=0;i<nStartPos.length;i++) BK,h$z7#6  
{ T)QZ9a  
if(!fileSplitterFetch.bDownOver) 0UV5}/2rP  
{ JY$B%R4;]  
breakWhile = false; rU
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break; Yc5{M*w  
} l5?fF6#j  
} w.tQ)x1h  
if(breakWhile) Q<TD5t9  
break; y]1:IJL2;  
TRB)cJZ?  
if|j)h&  
//count++; M6$9-  
//if(count>4) EVovx7dr  
// siteStop(); !uIT5D  
} DyZe+,g;S  
=_(i#}"A  
Y8*k18~  
System.err.println("文件下载结束！"); #. mc+n:I  
} [(%6]L}  
catch(Exception e){e.printStackTrace ();} >FrF"u:kM  
} +f#oij  
,mpvGvAI  
=P* YwLb  
//获得文件长度 \FVm_)  
public long getFileSize() o;.6Y `-fJ  
{ x6=Yt{  
int nFileLength = -1; qs$%/  
try{ < 0S+[7S"  
URL url = new URL(siteInfoBean.getSSiteURL()); jt({@;sU[<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q(tdBd'o6  
httpConnection.setRequestProperty("User-Agent","NetFox"); q]1HCWde  
/jBjqE;_  
wI\ n%#  
int responseCode=httpConnection.getResponseCode(); YX||\  
if(responseCode>=400) nveHLHvC7  
{ .=y-T=}  
processErrorCode(responseCode); e1*<9&S  
return -2; //-2 represent access is error o6{[7jI  
} Mi|PhDXMh  
>]6inS9  
;.%Ii w&WG  
String sHeader; 1J(` kQ)c  
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#bFJ6;g=V  
for(int i=1;;i++) I/whpOg  
{ yJ(BPSt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >U.)?>G/dt  
//Utility.log(in.readLine()); E=Z;T  
sHeader=httpConnection.getHeaderFieldKey(i); J;?#Zt]`L  
if(sHeader!=null) <r[5 S5y  
{ [&6VI?  
if(sHeader.equals("Content-Length")) *}yOL [  
{ :n1^Xw0q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?Hb5<,1u3  
break; p&Os5zw;|  
} D{%l 4og  
} }3G`f> s  
else /h/f&3'h  
break; +`;YK7o  
} bn
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} W(5et5DN,  
catch(IOException e){e.printStackTrace ();} `# N j8  
catch(Exception e){e.printStackTrace ();} Z/y&;N4   
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Utility.log(nFileLength); *2K/)(  
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return nFileLength; SGuR
-$U`)  
} D..dGh.MY  
sTn}:A6  
v() wngn  
//保存下载信息（文件指针位置） qs96($  
private void write_nPos() .XD.'S  
{ u@(z(P  
try{ s-\.j-Sa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (MI8Kkb1d  
output.writeInt(nStartPos.length); 3J^"$qfSn  
for(int i=0;i<nStartPos.length;i++) ^A4bsoW  
{ Ro&s\T+d  
// output.writeLong(nPos); 4$j7DJ8d
j  
output.writeLong(fileSplitterFetch.nStartPos); v[3QI7E3  
output.writeLong(fileSplitterFetch.nEndPos); 1qEpQ
.:](  
} MfX1&/Z+  
output.close(); {8'f>YP  
} ; O6Ez-"  
catch(IOException e){e.printStackTrace ();} pZpAb+  
catch(Exception e){e.printStackTrace ();} <ptskbu  
} ;oej~  
+[ +4h}?  
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//读取保存的下载信息（文件指针位置） `k^d)9  
private void read_nPos() Q]Kc<[E  
{ TLBIM  
try{ 2ZZ%BV!s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j. @CB`  
int nCount = input.readInt(); f!3$xu5  
nStartPos = new long[nCount]; ]Wc:9Zb  
nEndPos = new long[nCount]; 1@xmzTC  
for(int i=0;i<nStartPos.length;i++) xJ2DkZ  
{ +#|| w9p  
nStartPos = input.readLong();  j-H2h  
nEndPos = input.readLong(); a&'!
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} q<5AB{Oj?  
input.close(); nnv&~
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} k9V#=,K0  
catch(IOException e){e.printStackTrace ();} K,ccM[hu|  
catch(Exception e){e.printStackTrace ();} 8'niew 5d  
} Ia>07av  
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private void processErrorCode(int nErrorCode) EWI2qaSnO  
{ my.%zF  
System.err.println("Error Code : " + nErrorCode); ^Po^Co  
} \Zpg,KOT  
,*y\b|<j  
.(RX;.lw  
//停止文件下载 <)D)j[  
public void siteStop() EAPLe{qw:q  
{ hI+mx  
bStop = true; !Vtj:2PQL  
for(int i=0;i<nStartPos.length;i++) 'Gr}<B$A3  
fileSplitterFetch.splitterStop(); Q+Sx5JUR~  
X&s@S5=r]  

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} y4jJ&  
} RM5$O+"  
//负责部分文件的抓取 IB'gY0*  
**FileSplitterFetch.java |a>W9Ym  
*/ +7`7cOqXg  
package NetFox; '@jP$6T&  
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M,uQ8SZA[  
import java.io.*; v;%>F)I  
import java.net.*; )z:"P;b"Nl  
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public class FileSplitterFetch extends Thread { <k41j=d  
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*$+:Cbe-F  
String sURL; //File URL ><l|&&e-  
long nStartPos; //File Snippet Start Position w=|"{-ijo  
long nEndPos; //File Snippet End Position aMLtZ7i>  
int nThreadID; //Thread's ID Vr|sRvz  
boolean bDownOver = false; //Downing is over li4"|T&  
boolean bStop = false; //Stop identical 1@$n)r`  
FileAccessI fileAccessI = null; //File Access interface AW6"1(D  
L}*s_'_e^>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @4ccZ&`  
{ j\/Rjn+:[  
this.sURL = sURL; "DpgX8lG_  
this.nStartPos = nStart; D^\gU-8M  
this.nEndPos = nEnd; <w9<G  
nThreadID = id; ZQ MK1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p+ki1!Ed  
} .huk>   
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public void run() 5[qCH(6  
{ (^U 8wit/  
while(nStartPos < nEndPos && !bStop) \DgWp:|  
{ gq:2`W&5  
x_k@hGSC  
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try{ /:BM]K  
URL url = new URL(sURL); q]^Q?r<g::  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\2&?#GZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); qsUob  
String sProperty = "bytes="+nStartPos+"-"; 2k}8`P;  
httpConnection.setRequestProperty("RANGE",sProperty); <,X?+
hr  
Utility.log(sProperty); <$:Hf@tpMo  
*# 7 1aZ  
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InputStream input = httpConnection.getInputStream(); D.ajO^[  
//logResponseHead(httpConnection); ?gGmJl  
HW"';M%  
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byte[] b = new byte[1024]; C7hJE-  
int nRead; >EJ
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "QV
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{ ZD`9Ez)5  
nStartPos += fileAccessI.write(b,0,nRead); (Y[q2b  
//if(nThreadID == 1) ;_TPJy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IW~q,X+`V  
} UpoTXAD}k  
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Utility.log("Thread " + nThreadID + " is over!"); Y6R+i0guz  
bDownOver = true; =Felo8+   
//nPos = fileAccessI.write (b,0,nRead); iN]#
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} b-Uy&+:X*d  
catch(Exception e){e.printStackTrace ();} |s}7<A  
} `%5~>vPS  
} (&=gM  
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//打印回应的头信息 1|Q-|jq`  
public void logResponseHead(HttpURLConnection con) wq6.:8Or-]  
{ [<!4 a  
for(int i=1;;i++) K7jz*|2  
{ j56Dt_  
String header=con.getHeaderFieldKey(i); `yXJaTbo  
if(header!=null) J;mvD^`g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0DR:qw  
Utility.log(header+" : "+con.getHeaderField(header)); g"P!KPrf1p  
else 4Ww.CkRG  
break; j3kcNb  
} 4w)aAXK  
} Q!&@aKl  
$,&3:ke1  
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public void splitterStop() V]fsjpvlmr  
{ rO;Vr},3\%  
bStop = true; +j">Ju6Q;.  
} ~4t7Q  
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} V+yyy-/  
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/* F%s'R 0l  
**FileAccess.java q<2b,w==  
*//文件访问(定位，写) 5jS8{d0  
package NetFox; |OVD*A  
import java.io.*; +|OrV'  
jykY8;4  
"
^3pP(8;~  
public class FileAccessI implements Serializable{ Pm}
 
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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 _=s{,t &u  
RandomAccessFile oSavedFile; /E|Ac&Qk  
long nPos; 7Ns1b(kU  
_1sjsGp>  
1|8<!Hx#-  
public FileAccessI() throws IOException |mO4+:-~D+  
{ >kN%R8*Sx  
this("",0); 6Pzz= ai<  
} s+jL BY  
-NgL4?p=  
<:gNx%R  
public FileAccessI(String sName,long nPos) throws IOException D)my@W0,  
{ QaAWO  
oSavedFile = new RandomAccessFile(sName,"rw"); 'nR'o /!  
this.nPos = nPos; "7RnT3  
oSavedFile.seek(nPos);
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} {:!CA/0Jx  
 Eqc,/  
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public synchronized int write(byte[] b,int nStart,int nLen) Z8yt8O  
{ 9}_ccq  
int n = -1; Bf-KCqC".  
try{ CPj8`kl  
oSavedFile.write(b,nStart,nLen); 0Ia8x?80V  
n = nLen; X$4MpXx  
} 
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catch(IOException e) $w@0}5Q  
{ m0(]%Kdw  
e.printStackTrace (); }wkZ\q[  
} = "N?v-  
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#;WKuRv  
return n; @UG%B7  
} o[ua$+67E  
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} +uD4$Wt_F  
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|
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/* BA 9c-Ay  
**SiteInfoBean.java ?-HLP%C('  
*/ $QB~ x{v@n  
package NetFox; %x2_njDd  
#3WKm*T/  
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public class SiteInfoBean { %Uz 5Ve  
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private String sSiteURL; //Site's URL #@cOyxUt  
private String sFilePath; //Saved File's Path HL*Fs /W  
private String sFileName; //Saved File's Name /`b(} m  
private int nSplitter; //Count of Splited Downloading File 2x
x  
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HT: p'Yyi  
public SiteInfoBean() >Y\$9W=t  
{//nSplitter的缺省值为5 1m5=N
u  
//default value of nSplitter is 5 |'R^\M Q  
this("","","",5); 6|O2i j-J  
} MMYV8;c  
Oz:J8l%  
#,4CeD|(D,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^G~C#t^  
{ },;ymk|g[  
sSiteURL= sURL; J_H=GHMp}  
sFilePath = sPath; e~+VN4D&b>  
sFileName = sName; 8FmRD  
this.nSplitter = nSpiltter; Az
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9
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k ='c*`IE  
} 2Kg+SLU[~  
[!k#au+#c  
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public String getSSiteURL() 5jb/[i^V  
{ "iC*Eoz#.  
return sSiteURL; j18qY4Gw)  
} \`!M5FJ  
r{Cbx#;  
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public void setSSiteURL(String value) @0mR_\u\  
{ c2aW4TX2  
sSiteURL = value; .-[d6Pn
w  
} ha%3%O8Z  
mK>c+ u)  
+F9)+wT~;q  
public String getSFilePath() V:wx@9m)  
{ Bn5O;I13  
return sFilePath; \en}8r9cy  
} dg?[gD8!4&  
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iLy
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public void setSFilePath(String value) 6u'+#nm  
{ a+--2+~=  
sFilePath = value; _W3>Km-A=/  
} -ST[!W V  
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c~0hu*&  
public String getSFileName() r/32pY  
{ #RG/B2  
return sFileName; )0Lno|l  
} ^Iz(V2  
V\ 7O)g
 
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public void setSFileName(String value) 9MmAoLm  
{ *&m{)cTs  
sFileName = value; '|9fDzW"]  
} rerl-T<3  
(q@DBb4  
)G a%Eg9  
public int getNSplitter() 0rjH`H]M  
{ UZ`GS$D@  
return nSplitter; +-VkRr#  
} %]zaX-2dm!  
wTL&m+xr  
ZE!dg^-L  
public void setNSplitter(int nCount) "i}?jf {a  
{ !5/jDvh  
nSplitter = nCount; }aPx28:/  
} FBR]) h'Z  
} .BWCGb2bH  
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ZP]l%6\.  
/* <ah!!  
**Utility.java
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*/ 2}ttCm  
package NetFox; cr&sI=i  
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public class Utility { /hojm6MM  
>sUavvJ~x  
+~E;x1&'  
public Utility() p\7(`0?8VN  
{ *G<K@k  
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IC1oW)  
} Gs2|#*6  
nO'lN<L  
//线程睡眠 s Y^#I  
public static void sleep(int nSecond) f:=y)+@1My  
{ 6eUM[C.  
try{ F@76V$U.  
Thread.sleep(nSecond); B``)  
} :$>Co\D  
catch(Exception e) z/B[quSio  
{ aQMUC6cPM@  
e.printStackTrace (); K
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} .5i\L OTd  
} J<<Ph  
 <|Pw*L$  
//日志 x9,X0JO  
public static void log(String sMsg) x8#bd{  
{ wNHvYulI  
System.err.println(sMsg); epcBr_}  
} wVSk.OOB  
DRo?7_  
^F>C|FJ2  
public static void log(int sMsg) yc#0c[ZQu  
{ lji&]^1  
System.err.println(sMsg); X0h`g)Bbf  
} th$?#4SbR  
} (iwZs:k-  
baD`k?](  
l(o#N'!j4  
/* d3$*z)12`  
**TestMethod.java {z4v_[-2CF  
*/ yo#aX^v~y  
package NetFox; rv75R}.6R^  
6 J&_H(^  

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public class TestMethod { r+4<Lon~  
qmWK8}F.cE  
6`ZHFe
m  
public TestMethod() Au-_6dT  
{ ///xx/weblogic60b2_win.exe @Kx@ 2#~b  
try{ s/;iZiWK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q_h=O1W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); deRnP$u0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cZd9A(1"^  
fileFetch.start(); +@U}gk;#c  
} rq[+p  
catch(Exception e){e.printStackTrace ();} d]89DdZk  
)_m#|U?Rex  
[>rX/a%c  
} zNZ"PYh<u  
j}uVT2ZE%  
*J ]2"~_.  
public static void main(String[] args) Ju0W  
{ F8c^M</  
new TestMethod(); l*v6U'J  
} TA2?Ia;@xV  
} t_VF=B^LuR  
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