http断点续传简单实现（java)

/* '`<w#z}AF  
**SiteFileFetch.java AzxXB  
*/ ofv)SCjd  
package NetFox; tnG# IU *  
import java.io.*; NN`uI6=  
import java.net.*; {.\Tt
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public class SiteFileFetch extends Thread { m9Hit8f@Q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >e"#'K0?\  
long[] nStartPos; //开始位置 YUIi;  
long[] nEndPos; //结束位置 :08,JL{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?S$P
9^ii'  
long nFileLength; //文件长度 xF44M]i  
boolean bFirst = true; //是否第一次取文件 8ITdS
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boolean bStop = false; //停止标志 #YOA`m,'  
File tmpFile; //文件下载的临时信息 E\,
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DataOutputStream output; //输出到文件的输出流 K6)j0]K1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $p?aVO  
public SiteFileFetch(SiteInfoBean bean) throws IOException %|i`kYsy  
{ !I Qck8Y  
siteInfoBean = bean; Y.r+wc]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h2""9aP!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5[u]E~Fl}  
if(tmpFile.exists ()) ,WB{i^TD  
{ (=@h23 vH  
bFirst = false; /~f'}]W  
read_nPos(); N
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} }~e%J(  
else H+Sz=tg5  
{ 1 Ya`| ?FS  
nStartPos = new long[bean.getNSplitter()]; A$:U'ZG_  
nEndPos = new long[bean.getNSplitter()]; j ?(&#  
} ^M>
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} l2P=R)@{  
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public void run() 2V;PYI  
{ 1HZO9cXJ  
//获得文件长度 n#OB%@]<V  
//分割文件 s+?zL~t  
//实例FileSplitterFetch pD#rnp>WWt  
//启动FileSplitterFetch线程
[mGLcg6Fw  
//等待子线程返回 M1iS(x  
try{ )f<z%:I+Z  
if(bFirst) m-"w0Rl1T  
{ 3x'|]Ns  
nFileLength = getFileSize(); "5wa91*  
if(nFileLength == -1) X*@dj_,  
{ _t #k,;  
System.err.println("File Length is not known!"); 9c :cw  
} ` v@m-j6  
else if(nFileLength == -2) Ge-vWf-RbB  
{ ?'{SX9  
System.err.println("File is not access!"); tHwMX1 IG  
} VZmLS 4E  
else ByNn  
{ 9e,0\J  
for(int i=0;i<nStartPos.length;i++) JB[~;nLlC  
{ czRFMYE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hp-<2i^"!  
} Y^EcQzLw  
for(int i=0;i<nEndPos.length-1;i++) r:ptQo`1-  
{ >_"an~Ss  
nEndPos = nStartPos[i+1]; $6iX   
} S2VA{9:m  
nEndPos[nEndPos.length-1] = nFileLength; Q:k}Jl  
} 'F0e(He@,  
}  DwE[D]7o  
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!58@pLJw  
//启动子线程 !\.pq 2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X
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for(int i=0;i<nStartPos.length;i++) WuUk9_g  
{ GM f `A,>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T&u5ki4NE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Doyx[zZ  
nStartPos,nEndPos,i); qm8B8&-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cl8Cg~2  
fileSplitterFetch.start(); CSq4x5!_7>  
} \B,@`dw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P%&0]FCx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >rKIG~P_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !0LWa"  
nEndPos = " + nFileLength); My[pr_xg  
// fileSplitterFetch[nPos.length-1].start(); ;LSANr&  
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c>:wd@w  
//等待子线程结束 9} M?
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//int count = 0; ?:I*8Fj  
//是否结束while循环 hVAn>_(  
boolean breakWhile = false; RF53Jyt  
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_ y8Wn}19f  
while(!bStop) o5uph=Q{  
{ ""F5z,'  
write_nPos(); jc[Y}gd,  
Utility.sleep(500); V/ uP%'cd  
breakWhile = true; '3DXPR^B6  
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for(int i=0;i<nStartPos.length;i++) YdC6k?tzS  
{ Nk VK  
if(!fileSplitterFetch.bDownOver) /,&<6c-Q@W  
{ [<6^qla  
breakWhile = false; `l){!rg8IC  
break; KD7dye  
} ]uJ"?k=  
} {|_M #w~&  
if(breakWhile) ipgC RHE  
break; j8{i#;s!"  
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J1RJ*mo7,  
//count++; J76kkW`5  
//if(count>4) cyv`B3}  
// siteStop(); 4n g]\ituS  
} 6@ IXqKz  
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System.err.println("文件下载结束！"); L<-_1!wh  
} )<;Y-u.UW  
catch(Exception e){e.printStackTrace ();} Eog0TQ+*  
} )E@.!Ut4o  
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//获得文件长度 >j(_[z|v3  
public long getFileSize() wyj{zWRJp  
{ BsqP?/  
int nFileLength = -1; (X1e5j>Ru  
try{ l%puHZ)t  
URL url = new URL(siteInfoBean.getSSiteURL()); 5Y'qaIFR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~f1%8z  
httpConnection.setRequestProperty("User-Agent","NetFox"); lVR~Bh  
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int responseCode=httpConnection.getResponseCode(); ag#S6E^%S  
if(responseCode>=400) z.9U}F  
{ %x{kc3PnO  
processErrorCode(responseCode); m=A(NKZ  
return -2; //-2 represent access is error >G*eNn  
} foF({4q7b^  
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String sHeader; H*&f:mfq  
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for(int i=1;;i++) EZy)A$|  
{ \fyRsa)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l7259Ro~  
//Utility.log(in.readLine()); ]&xk30  
sHeader=httpConnection.getHeaderFieldKey(i); (vP
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if(sHeader!=null) _jI,)sr4ic  
{ )oDHeU<&  
if(sHeader.equals("Content-Length")) C]eSizS.  
{ '}JhzKNj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eJVjuG  
break; }=UHbU.n~!  
} V>)OpvoT#  
} ox>^>wR*  
else .TMs bZ|j  
break; ^aMg/.
j  
} g\(G\ tnu>  
} 4 \K7xM!  
catch(IOException e){e.printStackTrace ();} S)k*?dQ##R  
catch(Exception e){e.printStackTrace ();} C'+YQ]u  
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Utility.log(nFileLength); udF~5w H  
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return nFileLength; w%VU/6
~  
} HU}7zK2  
C:* *;=.  
YTX,cj#D^&  
//保存下载信息（文件指针位置） i]y<|W)Q3  
private void write_nPos() :O?MSS;~  
{ FLCexlv^  
try{ ,j}6? Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5C*Pd Wpl  
output.writeInt(nStartPos.length); t#/YN.@r  
for(int i=0;i<nStartPos.length;i++)  ZrxD`1L  
{ P[#e/qnXu|  
// output.writeLong(nPos); trA4R/ &  
output.writeLong(fileSplitterFetch.nStartPos); V>%rv'G8  
output.writeLong(fileSplitterFetch.nEndPos); Ic:(Gi- %  
} ,I$`-$_'  
output.close(); el<s8:lA  
} WZejp}x  
catch(IOException e){e.printStackTrace ();} gJXq^~-hd  
catch(Exception e){e.printStackTrace ();} 9ni1f{k  
} SSg8}m5)Q  
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//读取保存的下载信息（文件指针位置） '&R2U_  
private void read_nPos() @=Uh',F  
{ d(x\^z  
try{ =:,g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u+e{Mim  
int nCount = input.readInt(); Uq,^Wy  
nStartPos = new long[nCount]; qu6D 5t  
nEndPos = new long[nCount]; \0I_<  
for(int i=0;i<nStartPos.length;i++) n;C :0  
{ Apag{Z]^B  
nStartPos = input.readLong(); L>NL:68yN  
nEndPos = input.readLong(); |A9F\A->4  
} "]x'PI 4J  
input.close(); 5iw<>9X*  
} Jr!JHC9i  
catch(IOException e){e.printStackTrace ();} D~iz+{Q4  
catch(Exception e){e.printStackTrace ();} Uh4%}-;  
} !bx;Ta.  
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private void processErrorCode(int nErrorCode) ")5":V~fN  
{ Al^d$FaF  
System.err.println("Error Code : " + nErrorCode); J26VnK  
} {n.PF8A5X  
El".I?E*  
7\[@m3s  
//停止文件下载 M}-Rzc  
public void siteStop() |?xN\O^#}  
{ t%FwXaO#  
bStop = true; G]tn i  
for(int i=0;i<nStartPos.length;i++) SrJGTuXg  
fileSplitterFetch.splitterStop(); beGa#JH,  
o#gWbAG;]b  
|\t-g"~sN  
} (vnAbR#e  
} {.|CdqwY  
//负责部分文件的抓取 XS{Qnx_#  
**FileSplitterFetch.java Beo@K|3GN  
*/ "ycJ:Xv49  
package NetFox; P%VSAh\|n  
({)+3]x  
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import java.io.*; 4Uo&d#o)C-  
import java.net.*; W:nef<WH  
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public class FileSplitterFetch extends Thread { @)M9IOR  
D|p9qe5%  
9};8?mucr  
String sURL; //File URL _,0  
long nStartPos; //File Snippet Start Position $G+@_'  
long nEndPos; //File Snippet End Position EjR9JUu  
int nThreadID; //Thread's ID (D&3G;0tK  
boolean bDownOver = false; //Downing is over 0<@KG8@hI;  
boolean bStop = false; //Stop identical gzT*-  
FileAccessI fileAccessI = null; //File Access interface <w9JRpFY  
XJ\DVZ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (OL4Ex']  
{ MK~8}x2K  
this.sURL = sURL; iByf{I>+  
this.nStartPos = nStart; %E>Aw>]v  
this.nEndPos = nEnd; wo/\]5  
nThreadID = id; KC6.Fr{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [kB7@o  
} UHkMn  
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public void run() pa3{8x{9m  
{ QO~P7r|A  
while(nStartPos < nEndPos && !bStop) uyWunpT  
{ 2- h{N  
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try{ >\#*P'y`d  
URL url = new URL(sURL); Eyqa?$R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C2I_%nU Z1  
httpConnection.setRequestProperty("User-Agent","NetFox"); b\!_cb~"@  
String sProperty = "bytes="+nStartPos+"-"; $( kF#  
httpConnection.setRequestProperty("RANGE",sProperty); ]:-mbgW  
Utility.log(sProperty); ZJJY8k `  
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InputStream input = httpConnection.getInputStream(); 8/cX]J  
//logResponseHead(httpConnection); 5Ln,{vsv  
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1n8/r}q'H  
byte[] b = new byte[1024]; &wawr2)}  
int nRead; H$t_Xw==  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &PHTpkaam  
{ Bm<`n;m  
nStartPos += fileAccessI.write(b,0,nRead); ltSU fI  
//if(nThreadID == 1) k]|~>9eY]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $8h%a 8I  
} lfgq=8d  
/Cr%{'Pzk  
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Utility.log("Thread " + nThreadID + " is over!"); o:'MpKm  
bDownOver = true; ? :%@vM  
//nPos = fileAccessI.write (b,0,nRead); ec;o\erPG  
} I$G['`XX/  
catch(Exception e){e.printStackTrace ();} gz9j&W.  
} JPHL#sKyz  
} +3BN}  
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|YWD8 +  
//打印回应的头信息 C.-,^+t;g  
public void logResponseHead(HttpURLConnection con) [|$h*YK  
{ VCkq"f7cw  
for(int i=1;;i++) n( yn<  
{ Ll't>)  
String header=con.getHeaderFieldKey(i); YkSl^j[DHs  
if(header!=null) +Kc
  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &r/Mi%  
Utility.log(header+" : "+con.getHeaderField(header)); $%d*@'c  
else T?
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break; BDDlQci38  
} O0v}43J[  
} F/{!tx  
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public void splitterStop() RtS+<^2a;  
{ 0#hlsfc]\  
bStop = true; 1CZgb  
} T7%S #0,p  
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/{_:{G!Q0  
} 9TC,!0U{_.  
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/* /,yd+wcW#  
**FileAccess.java  mq.`X:e  
*//文件访问(定位，写) C<tl/NC  
package NetFox; dZ
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import java.io.*; J/$&NWF  
2%m BK  
\M^bD4';>  
public class FileAccessI implements Serializable{ Qw*|qGvy^  
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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 {VRf0c  
RandomAccessFile oSavedFile; CHX#^0m.  
long nPos; Wac&b  
0{D'n@veP  
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public FileAccessI() throws IOException k4J+J.|  
{ !F$6-0%  
this("",0); gwMNYMI  
} r,p%U!S<hV  
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public FileAccessI(String sName,long nPos) throws IOException oMa6(3T?E  
{ I\ob7X'Xu!  
oSavedFile = new RandomAccessFile(sName,"rw"); lymCH  
this.nPos = nPos; NXrlk  
oSavedFile.seek(nPos); W${Ue#w77  
} ^09,"<@k  
&h/Xku&0  
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public synchronized int write(byte[] b,int nStart,int nLen) TvbE2Q;/UL  
{ DvvK^+-~  
int n = -1; g2_"zDiw2  
try{ onzxx4bax  
oSavedFile.write(b,nStart,nLen); ON(kt3.h  
n = nLen;  qX{+oy5  
} F JyT+  
catch(IOException e) q_58;Bv  
{ (!WD1w
 
e.printStackTrace (); 8d'0N  
} ^1.By^ $  
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t{{QE:/  
return n; b\2 ds,  
} %'pgGC"|  
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} ?=Kduef  
> ~O.@|  
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/* JWxwJex  
**SiteInfoBean.java gPPkT"  
*/ ym1Y4,  
package NetFox; @q)d  
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public class SiteInfoBean { wibNQ`4k  
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private String sSiteURL; //Site's URL =I_'
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private String sFilePath; //Saved File's Path w}L[u r;I_  
private String sFileName; //Saved File's Name S f# R0SA  
private int nSplitter; //Count of Splited Downloading File 9->if/r,o  
p`qgrI`  
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public SiteInfoBean() Mo|2}nf  
{//nSplitter的缺省值为5 BI@[\aRLQ  
//default value of nSplitter is 5 $I?"lky  
this("","","",5); >A"(KSNL  
} pQB."[n  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ny/MJ#Lq  
{ Mi_$">1-W  
sSiteURL= sURL; [$UI8tV  
sFilePath = sPath; t]G:L}AOl  
sFileName = sName; J{G?-+`  
this.nSplitter = nSpiltter; @H8EWTZ  
seJ^s@H5l  
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} :ShT|n7  
jPkn[W# 6  
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public String getSSiteURL() ?a]mD
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{ )4;`^]F  
return sSiteURL; +=)+'q]S  
} ,V}WM%Km  
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public void setSSiteURL(String value) u*9V&>o  
{ rytyw77t(  
sSiteURL = value; ,a? oaPH  
} veECfR;  
4
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tZo} ;|~'  
public String getSFilePath() u ^RxD^=L  
{ LDa1X2N  
return sFilePath; #g!.T g'  
} alb.g>LNPP  
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public void setSFilePath(String value) X}0cCdW  
{ a8Wwq?@  
sFilePath = value; aw>#P   
} _o~nr]zx  
8q7
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public String getSFileName() c:.eGH_f  
{ ?Mfw]z"\C)  
return sFileName; ,
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} 93hxSRw  
0{SL&<&  
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public void setSFileName(String value) Z3!`J&  
{ Ek}A
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sFileName = value; 9N3eN  
} d'sZxU  
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;l^  
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public int getNSplitter() (7*}-Uy[C  
{ SgOheN-  
return nSplitter; *8XEYZa  
} @KAI4LP  
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0m ? )ROaJ  
public void setNSplitter(int nCount) :BTq!>s  
{ #e5\j\#.  
nSplitter = nCount; T
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} ml$o5&sN  
} rrv%~giU  
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/* KK &?gTa  
**Utility.java A5w6]:f2  
*/ 0ZO2#>gh$  
package NetFox; @=kSo -SX  
as=LIw}Q4  
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public class Utility { DlNX 3  
|^H5^k "Bv  
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public Utility() Wv/=
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{ GuL<Z1<c  
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} )\^-2[;  
pD]
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//线程睡眠 X\F|Tk3_  
public static void sleep(int nSecond) 5/z/>D;  
{ =nHgDrA_  
try{ gPc=2  
Thread.sleep(nSecond); t&DEb_"De  
} jF*j0PkNdb  
catch(Exception e) 29q _BR *:  
{ `@|$,2[C  
e.printStackTrace (); ^sg,\zD 'X  
} C"enpc_C/  
} 3oG,E;(  
>yh2Lri  
//日志 &iVs0R  
public static void log(String sMsg) \D&KC,i5f  
{ /H+a0`/  
System.err.println(sMsg); 7v_8_K  
} M& CqSd  
\5cpFj5%  
n{SJ_S#a.a  
public static void log(int sMsg) A.w:h;7  
{ 5E_YEBO/  
System.err.println(sMsg); 2dgd~   
} !5?<% *  
} *_g$MI  
YT8F#t8  
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/* ;ovP$ vl>  
**TestMethod.java W+1^4::+  
*/ H7+,*  
package NetFox; & "B=/-(  
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public class TestMethod { kz7(Z'pw  
4I5Y,g{6+  
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public TestMethod() IdxzE_@  
{ ///xx/weblogic60b2_win.exe W'TaBuCb  
try{ S>; 5[l 4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bK-
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); F1Bq$*'N$w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y L~W.H  
fileFetch.start(); O%HHYV%[m  
} dcWD(-  
catch(Exception e){e.printStackTrace ();} y$R_.KbO  
##4HYQ%E  
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} w.-!UD9/.x  
*G9V'9  
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public static void main(String[] args) 9k[9P;"F:  
{ 8q
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new TestMethod(); "G9xM
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} ?#Q #u|~  
} F^fdIZx  
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