http断点续传简单实现（java)

/* =F}qT|K  
**SiteFileFetch.java Zu~w:uNmU  
*/ [zXC\)&!  
package NetFox;
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import java.io.*; q'4P/2)va  
import java.net.*; fD3'Ye<R  
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public class SiteFileFetch extends Thread { &328pOT4  

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SiteInfoBean siteInfoBean = null; //文件信息Bean uPapINj  
long[] nStartPos; //开始位置 #I*{_|}=  
long[] nEndPos; //结束位置 *SIYZE'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _0FMwC#DY  
long nFileLength; //文件长度 'Bxj(LaV-  
boolean bFirst = true; //是否第一次取文件 /GM!3%'=  
boolean bStop = false; //停止标志 {2mF\A#.  
File tmpFile; //文件下载的临时信息 -84%6p2-  
DataOutputStream output; //输出到文件的输出流 R4P&r=?  
>
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uK`gveY  
public SiteFileFetch(SiteInfoBean bean) throws IOException >d
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{ J/:U,01  
siteInfoBean = bean; 'o4`GkNh)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  o0>|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :zq Un&k&  
if(tmpFile.exists ()) /U0Hk>$~(  
{ |)" y  
bFirst = false; uv8kea .(  
read_nPos(); +P Dk>PdEt  
} aXG|IN5 *m  
else i+_=7(
e  
{ "Da-e\yA  
nStartPos = new long[bean.getNSplitter()]; VzIZT{  
nEndPos = new long[bean.getNSplitter()]; HY1K(T  
} 8x LXXB  
x}Lj|U$r<X  
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} Yw]$/oP`  
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public void run() >~]|o  
{ a5s
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//获得文件长度 {d
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//分割文件 C22h*QM*  
//实例FileSplitterFetch &4sz:y4T>  
//启动FileSplitterFetch线程 e`H>}O/ai  
//等待子线程返回 'q_Z dw%  
try{ 0Zp5y@V8  
if(bFirst) N*6~$zl&  
{ o|vL:| 8Q  
nFileLength = getFileSize(); 5Phsh  
if(nFileLength == -1) 7I#C[:7x  
{ m@+QC$6S  
System.err.println("File Length is not known!"); qV idtSb  
} &JKQH  
else if(nFileLength == -2) 27+faR  
{ 0^nF: F  
System.err.println("File is not access!"); !lL `L\  
} qyFeq])  
else 4c{j9mh  
{ ]0 = |?n$7  
for(int i=0;i<nStartPos.length;i++) MffCk!]  
{ P0(LdZH6u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C4d'z(<  
} xV`l6QS  
for(int i=0;i<nEndPos.length-1;i++) 4 qY  
{ `-
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nEndPos = nStartPos[i+1]; 1KGf @u%-1  
} tKcC{  
nEndPos[nEndPos.length-1] = nFileLength; 3 yb]d5:U  
} M%Rr=  
} zh0T3U0D  
>o{JG(Rn  
4e.19H9  
//启动子线程 \P9ms?((A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =
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for(int i=0;i<nStartPos.length;i++) _?cum~A@  
{ )g^qgxnnV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oqysfLJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mDZA\P_  
nStartPos,nEndPos,i); qm_m8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )*XWe|H_  
fileSplitterFetch.start(); ?PTXgIC  
} ILl~f\xG)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !l0"nPM=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .{ljhE:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cF=WhP*f  
nEndPos = " + nFileLength); cN?/YkW?]  
// fileSplitterFetch[nPos.length-1].start(); %+,*$wk#*  
PN8#T:E  
7NWkN7:B  
//等待子线程结束 _F`JFMS  
//int count = 0; _->+Hjj ^  
//是否结束while循环 c/^jD5U7  
boolean breakWhile = false;  $RRX-  
}N(gP_?n  
CadIux^  
while(!bStop) $oM>?h_=  
{ 1L'Q;?&2H,  
write_nPos(); 3RGmmX"?G  
Utility.sleep(500); `{h)-Y``  
breakWhile = true; dR< d7  
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for(int i=0;i<nStartPos.length;i++) W^xO/xu1/  
{ [xrsa!$   
if(!fileSplitterFetch.bDownOver) IvkYM`%  
{ ::#[lw  
breakWhile = false; N\Lu+ x5  
break; .;Gx.}ITG6  
} 7=u Gf$/  
} 0asP,)i  
if(breakWhile) {D..(f1*u  
break; 3(t,x  
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//count++; NQ[X=a8N  
//if(count>4) ty#6%  
// siteStop(); P*7G?
 
} YZ8[h`z  
>K4Nn(~ys  
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System.err.println("文件下载结束！"); z_R^C%
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} /@1YlxKF  
catch(Exception e){e.printStackTrace ();} 52Lp_
M
 
} %Gyn.9\  
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//获得文件长度 %bF157X5An  
public long getFileSize()
Kx)PK  
{ LS9,:!$  
int nFileLength = -1; I}|a7,8   
try{ R6fkc^  
URL url = new URL(siteInfoBean.getSSiteURL()); Nj2l>[L;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \n,L600`q  
httpConnection.setRequestProperty("User-Agent","NetFox"); .AO-S)wHR  
b=2:\F  
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int responseCode=httpConnection.getResponseCode(); 5XHejHn>  
if(responseCode>=400) =j- ,yxBvJ  
{ <7rj,O1=  
processErrorCode(responseCode); >K,QP<B  
return -2; //-2 represent access is error ^W:a7cMw  
} : Bo
  
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~MH^R1=]  
String sHeader; 0?/gEr  
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for(int i=1;;i++) 9U.
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{ ~BuBma_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2Ah
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//Utility.log(in.readLine()); $6*Yh-"g  
sHeader=httpConnection.getHeaderFieldKey(i); wn.6l `  
if(sHeader!=null) u*=^>LD  
{ kw2yb   
if(sHeader.equals("Content-Length")) M$@~|pQ<  
{ )LKJfoo PY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cf"&22TQ+Z  
break; a$Ud"  
} ?K:\WW  
} pQ0*)}l,  
else yUo8-OaL7  
break; G93V=Bk=  
} |T/OOIA=sI  
} a5ZXrWv  
catch(IOException e){e.printStackTrace ();} 9XDSL[[  
catch(Exception e){e.printStackTrace ();} x X3I`  
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Utility.log(nFileLength); !\1)?&y9j  
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return nFileLength; e_|<tYx><  
} 985h]KQ  
IaSPwsvt'  
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//保存下载信息（文件指针位置） )mwwceN  
private void write_nPos() pA_u;*  
{ Hqs-q4G$  
try{ gAztdAsLM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7~Inxk;  
output.writeInt(nStartPos.length); W =Bw*o-  
for(int i=0;i<nStartPos.length;i++) l\V1c90m  
{ 'R-\6;3E>9  
// output.writeLong(nPos); `~=z0I  
output.writeLong(fileSplitterFetch.nStartPos); w{[
^  
output.writeLong(fileSplitterFetch.nEndPos); ;4b=/1M'  
} ^ /G ;  
output.close(); hO.b?>3NL  
} Fy E#@ R  
catch(IOException e){e.printStackTrace ();} e/+.^ '{  
catch(Exception e){e.printStackTrace ();} GU/P%c/V  
} q\i&ERr  
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//读取保存的下载信息（文件指针位置） Q) aZ0 Pt  
private void read_nPos() ,|VLOY^  
{ EU:N9oT  
try{ ub>:dNBN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >/4[OPB0R  
int nCount = input.readInt(); #V/{DPz  
nStartPos = new long[nCount]; 5ta;CG  
nEndPos = new long[nCount]; 0F- +)S?M[  
for(int i=0;i<nStartPos.length;i++) Uq'W<.v5  
{ S{e3aqT#N  
nStartPos = input.readLong(); 9<3}zwJ  
nEndPos = input.readLong(); wt
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} iZnLgkk@  
input.close(); JSju4TQ4  
} Gchs$^1`t  
catch(IOException e){e.printStackTrace ();} ;Krs*3 s  
catch(Exception e){e.printStackTrace ();} qP;1LAX  
} RZ{O6~VH  
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private void processErrorCode(int nErrorCode) )O+Zbn  
{ R8lja%+0$  
System.err.println("Error Code : " + nErrorCode); ZoJqJWsd  
} %$o[,13=  
= )3\B  
)_j(NX-C:  
//停止文件下载 Wm"#"l4  
public void siteStop() fCY??su*   
{ "dt}k$Gr  
bStop = true; nPI$<yW7F  
for(int i=0;i<nStartPos.length;i++) ?nL
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fileSplitterFetch.splitterStop(); L58H)V3Pn  
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} _>`9]6\&  
} /]J\/Z>  
//负责部分文件的抓取 9@"pR;X@  
**FileSplitterFetch.java &Lzd*}7  
*/ T'l
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package NetFox; SOsz=bVx  
,!^c`_Q\>@  
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import java.io.*; =?y0fLTc  
import java.net.*; l}(HE+?  
_\k?uUo&,^  
;! ?l8R  
public class FileSplitterFetch extends Thread { 85dC6wI4K  
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String sURL; //File URL ~e,l2 <  
long nStartPos; //File Snippet Start Position ~cO
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long nEndPos; //File Snippet End Position b1'849i'y=  
int nThreadID; //Thread's ID `IBNBJy
 
boolean bDownOver = false; //Downing is over _0^>^he  
boolean bStop = false; //Stop identical `q^qe>'  
FileAccessI fileAccessI = null; //File Access interface H-e$~vEbP  
t%^&b'/Z  
K^"l.V#J  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ( 6zu*H)  
{ kFkI[WKyZ  
this.sURL = sURL; W58?t6! =  
this.nStartPos = nStart; SnUR?k1  
this.nEndPos = nEnd; eF7I5k4  
nThreadID = id; mc2uI-W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wS,fj gX  
} 7
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public void run() zXlerQWUv  
{ jbZTlG  
while(nStartPos < nEndPos && !bStop) I~~":~&  
{ dJrUcZBr  
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try{ bnvY2-O6  
URL url = new URL(sURL); s"$K2k;J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8"d??3ZXJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); kQ&Q_FSO  
String sProperty = "bytes="+nStartPos+"-"; Z 369<
 
httpConnection.setRequestProperty("RANGE",sProperty); ,S(Z\[x0  
Utility.log(sProperty); Hq>hnCT  
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\BfMCA/  
InputStream input = httpConnection.getInputStream();  6; )5v  
//logResponseHead(httpConnection); AG%[?1IXW  
/4 Kd
  
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byte[] b = new byte[1024]; #Q=c.AL{  
int nRead; Qof%j@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RSB+Saf.8  
{ bxO/FrwTj{  
nStartPos += fileAccessI.write(b,0,nRead); hCgk78O?  
//if(nThreadID == 1) =tA;JB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iC!6g|]X  
} 'ks .TS&  
6q`)%"
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Utility.log("Thread " + nThreadID + " is over!"); <f.Eog  
bDownOver = true; .
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//nPos = fileAccessI.write (b,0,nRead); {gu3KV  
} |}YxxeAk  
catch(Exception e){e.printStackTrace ();} G9jf]Ye
;  
} )'7Qd(4WT  
} UNv!G/i-5  
/7+b.h])^  
=\5f_g2M  
//打印回应的头信息 G[u6X_Q  
public void logResponseHead(HttpURLConnection con) tZg)VJQys  
{ vy={ziJ  
for(int i=1;;i++) "u$XEA  
{ |Go$z3bx  
String header=con.getHeaderFieldKey(i); aTH$+f1?Q  
if(header!=null) !RwhVaSh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y.8nzlkE{  
Utility.log(header+" : "+con.getHeaderField(header)); y#`;[!  
else aEa+?6;D  
break; =\)zb'\=d  
} };P=|t(r  
} rxy5Nrue  
d2U?rw_  
v}AjW%rB  
public void splitterStop() hc0$mit  
{ 1.8"N&s  
bStop = true; |)&d9|
]  
} 5{DwD{Q  
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} hz<TjWXv'  
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0SIUp/.  
/* %2\Pe 2Z  
**FileAccess.java c`S
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*//文件访问(定位，写) v,~fG
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package NetFox; +`mI\+y,  
import java.io.*; <rui\/4NJ  
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public class FileAccessI implements Serializable{ ve.P{;;Ky  
.rwW5"RPq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Nq9M$Nt]  
RandomAccessFile oSavedFile; 6r@>n_6LY  
long nPos; /<+`4n  
cAVdH{$"  
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public FileAccessI() throws IOException $txF|Fj]^A  
{ )~nieQEZQ  
this("",0); {wz_ngQ  
} EDnZ/)6Gg  
f
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;GOu'34j  
public FileAccessI(String sName,long nPos) throws IOException [C;Neslo  
{ XUUP#<,s  
oSavedFile = new RandomAccessFile(sName,"rw"); BjTgZ98J  
this.nPos = nPos; 8~RJnwF^  
oSavedFile.seek(nPos); H*f2fyC1\  
} /e|qyWs  
4 540Lw'A  
${wp}<u_  
public synchronized int write(byte[] b,int nStart,int nLen) &?xmu204  
{
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int n = -1; +NvpYz  
try{ jr#*;go  
oSavedFile.write(b,nStart,nLen); x`IWo:j  
n = nLen; 5~2_wWjX  
} mtE+}b@(!&  
catch(IOException e) {%y|
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{ $[7/~I>m  
e.printStackTrace ();
>
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} @8A[HP  
}'>mT,ytgk  
*W,[k&;:  
return n; ^f"|<r  
} kw2d<I$]  
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} jk\V2x@DR  
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/* cyabqx  
**SiteInfoBean.java i`vy<Dvpz  
*/ utC^wA5U~  
package NetFox; 7&%#bMnw  
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B/n~ $  
public class SiteInfoBean { CW/L(RQ  
kr |k \  
?q2Yk/P  
private String sSiteURL; //Site's URL BTG_c_?]e  
private String sFilePath; //Saved File's Path Hfo<EB2Y9N  
private String sFileName; //Saved File's Name `f~$h?}3-@  
private int nSplitter; //Count of Splited Downloading File mD
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YH^@8   
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public SiteInfoBean() -XwS?*O  
{//nSplitter的缺省值为5 %,ScGQE  
//default value of nSplitter is 5 u3wd~.  
this("","","",5); Rxlv:  
} V U5</si+  
zx.SRs$  
"sY}@Q7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y>g
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{ r{SDJa  
sSiteURL= sURL; 87!m l  
sFilePath = sPath; l7@cov  
sFileName = sName; 8]1,EE<  
this.nSplitter = nSpiltter; IJDbm}:/e  
$}z/BV1I  
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} qZ@d:u  
mieyL9*n7  
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public String getSSiteURL() ssoE,6kS  
{ oK4xRv8Hd  
return sSiteURL; ^}wF^ _  
} V3d$C&<(  
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public void setSSiteURL(String value) DUF$-'A  
{ UA]fKi  
sSiteURL = value; =20 +(<  
} ji.?bKqHE  
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public String getSFilePath() )/~o'M3  
{ oj)(.X<8N  
return sFilePath; N#$]W"U  
} PCV#O63[  
Q&^\YgkCf  
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public void setSFilePath(String value) Y3(I;~$!  
{ Tm7LaM  
sFilePath = value; MEp{&#v|1  
} x7`+T1IJ  
;)P=WS:=  
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public String getSFileName() }:;UnE}  
{ Km,o+9?1gF  
return sFileName; R osU~OK  
} {9x>@p/  
;fN^MW@&[  
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public void setSFileName(String value) )EKWsGNe/  
{ .jtv Hr}U  
sFileName = value; ]+B.=mO_  
} ^W@%(,xb  
&?Q^i">cZ  
6
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public int getNSplitter() zDbO~.d  
{ 6iF&!Fd>J  
return nSplitter; ^&8hhxCPu|  
} {~s\a2YH  
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public void setNSplitter(int nCount) *,*O.#<6  
{ %.l={B,i  
nSplitter = nCount; "bWx<  
} lQvgq  
} T:H~Y+qnt  
9&`";
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/* j|N<6GSke  
**Utility.java zH9*w:"4<_  
*/ [C<
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package NetFox; M*Ej*
#  
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public class Utility { iF
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public Utility() w%\{4T~  
{ kS9;Tjcx  
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} Y Q.Xl_  
lz36;Fp  
//线程睡眠 8~s0%%{,M  
public static void sleep(int nSecond) d,Oagx  
{ \@N~{72:k  
try{ %iEdUV\$  
Thread.sleep(nSecond); NqNU:_}  
} ~1twGG_;  
catch(Exception e) }HmkTk  
{ P3Lsfi.  
e.printStackTrace (); CV\y60n  
} vTK8t:JQ~  
} \b8#xT}  
Hs:zfvD  
//日志 [[6"qq  
public static void log(String sMsg) A|:+c*7]  
{ RjPkH$u'Pj  
System.err.println(sMsg); 7wPI)]$  
} nLG)>L  
r `n|fD.  
{#4a}:3  
public static void log(int sMsg) H>;,r,  
{ G kG#+C0L  
System.err.println(sMsg); <*dcl2xS  
} 6-TYOUm  
} 1IS1P)4_0  
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XM w6b*O  
/* I2*(v%.-  
**TestMethod.java cRD;a?0/6s  
*/ 5dN>Xjpu  
package NetFox; dg|x(p#  
SOM? 0.  
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public class TestMethod { YGLq
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v~T)g"_|  
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public TestMethod() jl(D;JnF  
{ ///xx/weblogic60b2_win.exe E QU@';~8  
try{ fDplYn#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); . _|=Btoo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); izaqEz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3HYdb|y
 
fileFetch.start(); A%F8w'8(  
} g'7\WQ  
catch(Exception e){e.printStackTrace ();} N|2d9E  
V4ePYud;^  
n_RZ:<Gr  
} t=@d`s:R2  
kc P ZIP:  
W)/f5[L  
public static void main(String[] args) 9< 07# 8c.  
{ e@0|fB%2  
new TestMethod(); knG:6tQ  
} O TlqJ  
} oST)E5X;7  
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