http断点续传简单实现（java)

/* !%5ae82~3  
**SiteFileFetch.java D M(WYL{
 
*/ 5 WSu  
package NetFox; no- Lx-x  
import java.io.*; YLmzMD>  
import java.net.*; TU&6\]yF_  
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public class SiteFileFetch extends Thread { 9w'3d@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lc>)7UF  
long[] nStartPos; //开始位置 v+U( #"  
long[] nEndPos; //结束位置 Uhfm@1 cz&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 LI_>fuv"8  
boolean bFirst = true; //是否第一次取文件 sUN>uroi !  
boolean bStop = false; //停止标志 bq[j4xH0X  
File tmpFile; //文件下载的临时信息 +N5#EpW  
DataOutputStream output; //输出到文件的输出流 K&0op 4&  
|!{Q4<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） OLUQjvnU  
public SiteFileFetch(SiteInfoBean bean) throws IOException G3n* bv  
{ fN~kdm.  
siteInfoBean = bean; s:lar4>kM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \bY
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,X(P/x{B  
if(tmpFile.exists ()) $T{,3;kt  
{ O=LS~&=,  
bFirst = false; >Z?fX  
read_nPos(); Cbm  
} qH!}oPeU'  
else Nv "R'Pps  
{ ,Q4U<`ds!  
nStartPos = new long[bean.getNSplitter()]; fx %Y(W#5  
nEndPos = new long[bean.getNSplitter()]; X).UvPZ/  
} PxzeN
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} .+>w0FG.  
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6TJ5G8z_  
public void run() _6"vPN  
{ _Z+tb]  
//获得文件长度 }Uki)3(  
//分割文件 xEQ2iCeC  
//实例FileSplitterFetch }HtP8F8!x  
//启动FileSplitterFetch线程 ]#R'hL%f  
//等待子线程返回 pxjN\q  
try{ %41dVnWB^4  
if(bFirst) d=V4,:=S  
{ UfjLNe}wA  
nFileLength = getFileSize(); L;/#D>U(  
if(nFileLength == -1) 6g4CUP'Y  
{ 0i\ol9,bf  
System.err.println("File Length is not known!"); ^tX+<X  
} pq_DYG]  
else if(nFileLength == -2) 4NN-'Z>a  
{ 9+@"DuYc6  
System.err.println("File is not access!"); +#8?y 5~q  
} k1Zu&4C\  
else #<f}.P.Uc  
{ |t CD@M  
for(int i=0;i<nStartPos.length;i++) Sxf|gDC  
{ 3
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); GjZ@fnF  
} cw.Uy(ks|$  
for(int i=0;i<nEndPos.length-1;i++) $_ub.g|  
{ HVz-i{M  
nEndPos = nStartPos[i+1]; ~-x8@ /   
} 4 q
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nEndPos[nEndPos.length-1] = nFileLength; ^(m`5]qr7J  
} f/Km$#xOr  
} +*,rOK`C  
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//启动子线程 (bt^L3}a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G&:[G>iSm^  
for(int i=0;i<nStartPos.length;i++) zr@Bf!VG:  
{ I9*o[Jp5  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x={t}qDS8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W~p^AHco`  
nStartPos,nEndPos,i); ASY 
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6nt$o)[  
fileSplitterFetch.start(); T[xGF/
  
} A}C&WT~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (ii 5pnq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }D dg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?I}jsm1)  
nEndPos = " + nFileLength); 0uzis09  
// fileSplitterFetch[nPos.length-1].start(); U#G uB&V  
a8M.EFa:  
 wJ!  
//等待子线程结束 QNFA#`H  
//int count = 0; 1p
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//是否结束while循环 ( f8g}2  
boolean breakWhile = false; JiZ9ly(G  
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+f\tqucI3  
while(!bStop) V'c9DoSRI\  
{ ']$ttfJB  
write_nPos(); FU!U{qDI  
Utility.sleep(500); tnqW!F~  
breakWhile = true; U"-mLv"|  
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H;*:XLPF  
for(int i=0;i<nStartPos.length;i++) x)G/YUv76  
{ WP32t@  
if(!fileSplitterFetch.bDownOver) 5yp~PhHf  
{ R.A}tV=j#  
breakWhile = false; 9L%&4V}BIS  
break; @l"GfDfL9  
} yN{Ybp  
} %P_\7YBC>  
if(breakWhile) {0QD-b o  
break; QC4_\V
>[  
U,iTURd  
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//count++; >~BU<#  
//if(count>4) -2> L*"^  
// siteStop(); N$Gx$u3Cd  
} TW3
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System.err.println("文件下载结束！");  Ea\a:  
} Tj0eW(<!s  
catch(Exception e){e.printStackTrace ();} -rH4/Iby  
} m{%_5nW  
2:pq|eiF  
XF^c(*5  
//获得文件长度 @GnsW;$*~.  
public long getFileSize() h^hEyrJw  
{ OFRzzG@  
int nFileLength = -1; ]qVJ>  
try{ ip>dHj z  
URL url = new URL(siteInfoBean.getSSiteURL()); ::TUSz2/2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y#]Y$n  
httpConnection.setRequestProperty("User-Agent","NetFox"); y9s5{\H  
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!+>yCy$~_  
int responseCode=httpConnection.getResponseCode();  }O1F.5I1  
if(responseCode>=400) OPKX&)SE-  
{ =PZs'K  
processErrorCode(responseCode); 5V?1/  
return -2; //-2 represent access is error $S,
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} |0qk  
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^f`#8G7(  
String sHeader; >F-J}P  
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for(int i=1;;i++) ]/$tt@h  
{ aY {.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]iz5V
I@  
//Utility.log(in.readLine()); Fa/i./V2  
sHeader=httpConnection.getHeaderFieldKey(i); Oi7=z?+j  
if(sHeader!=null) Ak_;GvC!  
{ b-O4IDIT  
if(sHeader.equals("Content-Length")) /(}V!0\?  
{ eQ9x l
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e.HN%LrhS  
break; 4a3f!G$  
} Q z/pz_}  
} V_ ]4UE  
else 5
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break; -8pHjry'q  
} M?\)&2f[Z  
} N{q'wep  
catch(IOException e){e.printStackTrace ();} @+{S-iD"  
catch(Exception e){e.printStackTrace ();} u!@P,,NY  
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Utility.log(nFileLength); {:oZ&y)Ac  
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return nFileLength; +2?0]6EQ  
} PO}Q8Q3  
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//保存下载信息（文件指针位置） 8n73MF  
private void write_nPos() 2;&13%@!  
{ >WD^)W fa  
try{ [7Kn$OfP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .(hb8 rCM  
output.writeInt(nStartPos.length); @qe>ph[UA  
for(int i=0;i<nStartPos.length;i++) ~/#?OLj(T  
{ DRzpV6s  
// output.writeLong(nPos); b1&{%.3[  
output.writeLong(fileSplitterFetch.nStartPos); b\+|g9Tm  
output.writeLong(fileSplitterFetch.nEndPos); AnyFg)a<  
} 0 /kbxpih  
output.close(); M84LbgGM%  
} + zrwz\  
catch(IOException e){e.printStackTrace ();} J`8>QMK^5  
catch(Exception e){e.printStackTrace ();} cwD0 ~B
 
} 7L\GI`y  
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//读取保存的下载信息（文件指针位置） FlgB-qR]<n  
private void read_nPos() 8qc%{8  
{ 1Efl|lV  
try{ SB'YV#--  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nb8<8O ^  
int nCount = input.readInt(); eHJ7L8#  
nStartPos = new long[nCount]; %%Kg'{-:  
nEndPos = new long[nCount]; .;F+ QP0  
for(int i=0;i<nStartPos.length;i++) ~^euaOFU 6  
{ %zD-gw>  
nStartPos = input.readLong(); k1U~S`>$  
nEndPos = input.readLong(); v-gT 3kJ  
} #,PAM.rH  
input.close(); {x4[Bx1  
} _9@?Th&_e  
catch(IOException e){e.printStackTrace ();} ^(\Gonf<  
catch(Exception e){e.printStackTrace ();} __fR #D  
} /SKr.S61e  
"[?/I3{E  
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private void processErrorCode(int nErrorCode) _%2Umy|  
{ KVcZ@0[S  
System.err.println("Error Code : " + nErrorCode); `p{
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} 9HE(*S  
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+7Lco"\w<  
//停止文件下载 PM.SEzhm  
public void siteStop() cGc|n3(  
{ Q kZM(pG  
bStop = true; >h[!gXL^  
for(int i=0;i<nStartPos.length;i++) s4gNS eA  
fileSplitterFetch.splitterStop(); :ky<`Jfr`  
7L+X\oaB  
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} uT/B}`md  
} {~^)-^Wt:  
//负责部分文件的抓取 jDX<iX%e  
**FileSplitterFetch.java |3,V%>z  
*/
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package NetFox; 1D[P\r-  
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=b!J)]  
import java.io.*; )h0E$*  
import java.net.*; ^B5cNEO  
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b H?qijrC  
public class FileSplitterFetch extends Thread { dl6v <  
]kkBgjQbS  
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String sURL; //File URL gww^?j#  
long nStartPos; //File Snippet Start Position E)O|16f|>  
long nEndPos; //File Snippet End Position GWInN8.5  
int nThreadID; //Thread's ID FMdLkyK;  
boolean bDownOver = false; //Downing is over Dum`o^l#  
boolean bStop = false; //Stop identical jN%p5nZ^EK  
FileAccessI fileAccessI = null; //File Access interface Ke?gz:9j  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N+M&d3H`  
{ *fl{Y(_OO  
this.sURL = sURL;
BO4 K#H7  
this.nStartPos = nStart; K@P`
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this.nEndPos = nEnd; N 2"3~  #  
nThreadID = id; RF5q5<0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [DxefYyI  
} QG|GXp_q`  

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public void run() <.WM-Z  
{ e[QxFg0E  
while(nStartPos < nEndPos && !bStop) %A62xnX  
{ x$n~f:1Y  
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>.   
try{ F@$RV_M  
URL url = new URL(sURL); )@,90Vhh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >&;>PZBPCO  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q)Iv_N/  
String sProperty = "bytes="+nStartPos+"-"; hDljY!P>p  
httpConnection.setRequestProperty("RANGE",sProperty); )[^y t0%  
Utility.log(sProperty); $>r>0S#+\&  
%i$M/C"(  
i Y*o;z,~  
InputStream input = httpConnection.getInputStream(); AU)1vx(\w  
//logResponseHead(httpConnection); +9zJlL^A%  
vm\wO._  
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byte[] b = new byte[1024]; EmX>T>~#D  
int nRead; _ }E-~I>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2(m85/Hr\;  
{ ,-(T"Ph<  
nStartPos += fileAccessI.write(b,0,nRead); 7m:|u*ij2~  
//if(nThreadID == 1) !/Iq{2LX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z5G]p4  
} JF~1'"_f:  
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x&C%4Y_]  
Utility.log("Thread " + nThreadID + " is over!"); \3Dk5cSDk+  
bDownOver = true; C8IkpAD  
//nPos = fileAccessI.write (b,0,nRead); v7i^O`{eD?  
} iq"ob8.  
catch(Exception e){e.printStackTrace ();} D|@bGN  
} [%@2
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} {=UFk-$=  
]} 61vV  
0QMTIAW6h  
//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) @#RuSc  
{ 4k8*E5cx  
for(int i=1;;i++) yND"bF9  
{ V0K16#}1gM  
String header=con.getHeaderFieldKey(i); lVPOYl%
 
if(header!=null) fUC9-?(K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &+ KyPY+  
Utility.log(header+" : "+con.getHeaderField(header)); n(g)UNx  
else opsQn\4DZ?  
break; hAm/mu  
} E2@`d6  
} ^ eQFg>  
%Y~>Jl  
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public void splitterStop() 5?WYsj"  
{ (Uk>?XAr  
bStop = true; Cyq?5\a  
} vT|`%~Be  
xJ{_qP  
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} ,57$N&w  
07V8;A<,  
:ygWNK[6D  
/* 'JieIKu  
**FileAccess.java DAfyK?
+UL  
*//文件访问(定位，写) H&#{l)  
package NetFox; *U;'OWE[  
import java.io.*; +TK3{5`!Ae  
`K*b?:0lp  
';0 qj$#  
public class FileAccessI implements Serializable{ ,R?np9wc  
k|xtrW`qo;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `lO(s%HC  
RandomAccessFile oSavedFile; :4:N f  
long nPos; Z\~GU*Y.e  
j%L&jH6@  
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public FileAccessI() throws IOException ]5}=^  
{ \\06T`  
this("",0); \8S~c8Z~  
} ?-MP_9!JK  
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ljC(L/I  
public FileAccessI(String sName,long nPos) throws IOException lhH`dG D
 
{ >5hhd38  
oSavedFile = new RandomAccessFile(sName,"rw"); eg/<[ A:  
this.nPos = nPos; -`b8T0?oK  
oSavedFile.seek(nPos); |l0Ea  
} QSw<%pcJE@  
oR .cSGh  
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public synchronized int write(byte[] b,int nStart,int nLen) ehNzDr\s  
{ :kMHRm@{  
int n = -1; z'7[Tie  
try{ >&,[H:Z  
oSavedFile.write(b,nStart,nLen); /PzcvN  
n = nLen; g7\,{Bw#E  
} `F t]MR  
catch(IOException e) 69m ;XdkKz  
{ |4(~%| 8{  
e.printStackTrace (); 3S*AxAeg  
} 1x)ZB~L  
^n1%OzGK#  
q:\g^_!OGA  
return n; NVKC'==0  
} g.py+ ZFJ  
= ?D(g  
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} +Hvc_Av''  
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/* =Prb'8 W  
**SiteInfoBean.java : _e#  
*/ Byl^?5  
package NetFox; !RB)_7  
<"N_j]wD  
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public class SiteInfoBean { ]\-^>!F#K  
d^03"t0O]  
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private String sSiteURL; //Site's URL :W#rhuzC  
private String sFilePath; //Saved File's Path +4;uF]T  
private String sFileName; //Saved File's Name 5|3e&  
private int nSplitter; //Count of Splited Downloading File (*}yjUYLZ  
S$)*&46g  
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public SiteInfoBean() z]B]QB Y[  
{//nSplitter的缺省值为5 f()FY<b  
//default value of nSplitter is 5 $`ZzvZ'r  
this("","","",5); 32DbNEk  
} zgx&
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L`f^y;Y.  
5oEV-6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o#) {1<0vg  
{ *IgE
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sSiteURL= sURL; De7Ts  
sFilePath = sPath; =4V&*go*\  
sFileName = sName; ZkL8
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this.nSplitter = nSpiltter; dQoYCS}IaV  
4[Z\

?[  
glDcUCF3  
} v+p{|X-  
0a8/B>  
{3;AwhN0H  
public String getSSiteURL() ;g{qYj_  
{ O~j> ?  
return sSiteURL; ojYbR<jn9  
} Xq'cA9v=$J  
EA ]+vq  
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public void setSSiteURL(String value) ? WJ> p  
{ ^`un'5Vk  
sSiteURL = value; S$
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} >U F  
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public String getSFilePath() BA\/
YW @  
{ u]}s)SmDk  
return sFilePath; l/;X?g5+  
} B8E'ddUw  
4iSa7YqhBT  
RMMd#/A@}  
public void setSFilePath(String value) W3`>8v1?o  
{ zJe#m|Z  
sFilePath = value; f{SB1M   
} @`\VBW  
(&/2\0QV  
}VDqj}is  
public String getSFileName() wFG3KzEq ~  
{ *s@Qtgu  
return sFileName; U qG .:@T  
} {vAE:W.s  
$w"$r$K9K  
Ol4+_n8xj  
public void setSFileName(String value)  >S$Z  
{ ss;R8:5  
sFileName = value; xsWur(>]  
} 5 ae2<Y=  
F~A'X  
[O: !(Gje  
public int getNSplitter() SG6sw]x  
{ j*~T1i
 
return nSplitter; ySI~{YVM  
} VfT*7_  
~-wPP
{!  
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public void setNSplitter(int nCount) (O0Urm  
{ R|i/lEq  
nSplitter = nCount; H'Yh2a`!o  
}  i2~  
} V5}B:SUB  
s-dLZ.9F  
B"%{i-v>**  
/* @?h/B=56  
**Utility.java 6uKTGc4  
*/ Jx'i2&hGN  
package NetFox; M'_9A  
Tw +  
q^6+!&"  
public class Utility { B]tIi^  
ve&zcSeb  
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public Utility() 'Ei;^Y 1e  
{ fS^!ZPe1  
zt
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~|<m,)!  
} a#c6[!  
2h?uNW(0Q  
//线程睡眠 mrX^2SR  
public static void sleep(int nSecond) ~on(3|$  
{ b(9FZ]7S  
try{ >I=2!C1w  
Thread.sleep(nSecond); ZJlEKib%2  
} z0/} !  
catch(Exception e) WJ*n29^N^h  
{ %vBhLaE  
e.printStackTrace (); 4DTzSy:x  
} `"%T=w  
} ;E'"Ks[GH  
OgX6'E\E  
//日志 ETB6f  
public static void log(String sMsg) O:da-xWJ  
{ p ;|jI1  
System.err.println(sMsg); < y*x]}  
} m*mm\wN5  
|ae975  
P6MRd/y |  
public static void log(int sMsg) gzeQ|m2]  
{ >MPr=W%E  
System.err.println(sMsg); g[w,!F  
} Z}-Vf$O~  
} JMTvSXr  
n8.kE)?  
SXt{k<|  
/* Z{H5oUk  
**TestMethod.java bGorH=pb5R  
*/ t='# |');  
package NetFox; ;[a|9T
PR  
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public class TestMethod { NH0qVQ@A  
, lJv  
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ic%  
public TestMethod() /EG~sR
vl}  
{ ///xx/weblogic60b2_win.exe 3QpYmX<E  
try{ e)?Fi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); frBX{L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !Kv@\4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (!:cen~|[  
fileFetch.start(); )Z %T27r,^  
} JAI)Eqqv]  
catch(Exception e){e.printStackTrace ();}  aH#l9kCb  
bMU(?hb  
z~A]9|/61v  
} @JRNb=?a  
3"{.37Q  
~xoF6CF  
public static void main(String[] args) 77Bgl4P  
{ pFJB'=c  
new TestMethod(); k#5}\w!  
} c5mZG7-  
} U"50_O  
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