http断点续传简单实现（java)

/* +W}f0@#)<  
**SiteFileFetch.java 2yNlQP8%  
*/ 1/z1~:Il  
package NetFox; vDemY"wz  
import java.io.*; S=o/n4@}  
import java.net.*; E5rNC/Ul$$  
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public class SiteFileFetch extends Thread { SWu=n1J.?H  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zr
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long[] nStartPos; //开始位置 Cpr}*A   
long[] nEndPos; //结束位置 p|Ln;aYc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &EMm<(.]a  
long nFileLength; //文件长度 sU>*S$X8  
boolean bFirst = true; //是否第一次取文件 </eh^<_~  
boolean bStop = false; //停止标志 kmf4ax h1  
File tmpFile; //文件下载的临时信息 8=$@azG  
DataOutputStream output; //输出到文件的输出流 eI@O9<.&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5d)G30  
public SiteFileFetch(SiteInfoBean bean) throws IOException (Az^st/_  
{ X(8]9  
siteInfoBean = bean; 2/GH5b(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4CDmq[AVS[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Qr/?tMALc  
if(tmpFile.exists ()) `VHm,g2  
{ dsh}-'>  
bFirst = false; ukN#>e+L1  
read_nPos(); <1"6`24  
} dM QnN[d6  
else 4m~\S)ad  
{ Axr'zc  
nStartPos = new long[bean.getNSplitter()]; !nu#r$K(  
nEndPos = new long[bean.getNSplitter()]; '  _N >  
} )/BKN`,  
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} {MIs%w.G  
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public void run() o;"!#Z 1SJ  
{ *d@}'De{8  
//获得文件长度 5ewQjwW0  
//分割文件 Ouj5NL  
//实例FileSplitterFetch ;$86.2S>B  
//启动FileSplitterFetch线程 9AS,-5;XQ  
//等待子线程返回 ,7eN m>$  
try{ a+MC[aFr  
if(bFirst) TiH(HW|:  
{ $u>^A<TBN  
nFileLength = getFileSize(); U\51j  
if(nFileLength == -1) r!(~Y A  
{ ieObo foD  
System.err.println("File Length is not known!"); )xi|BqQz  
} BV<LIrAS  
else if(nFileLength == -2) B6
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{ ek.L(n,J|  
System.err.println("File is not access!"); aFhsRE?YC=  
} eM8u
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else 5t0$nKah]  
{ ,]o32@  
for(int i=0;i<nStartPos.length;i++) D@mDhhK_  
{ Am-JB
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8,%y`tUn>u  
} z2-=fIr.h  
for(int i=0;i<nEndPos.length-1;i++) wLW!_D,/R  
{ +^`c"qJo  
nEndPos = nStartPos[i+1]; 1,4kw~tA  
} ym-212wl  
nEndPos[nEndPos.length-1] = nFileLength; Hd4&"oeY  
} 55hJRm3  
} [j&>dE  
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//启动子线程 +&JF|#FQ`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; puDy&T  
for(int i=0;i<nStartPos.length;i++) rGx1>xd(k  
{ (R.k.,z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R D)dw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^5xY&1j  
nStartPos,nEndPos,i); P[^!Uq[0n7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N@*v'MEko%  
fileSplitterFetch.start(); 7kleBDDT  
} 1&wLNZXH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;IwC`!(#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,VbP$1t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,~c:P>v=  
nEndPos = " + nFileLength); D_'Zucq  
// fileSplitterFetch[nPos.length-1].start(); az7L0pp  
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//等待子线程结束 sA:0b5_a  
//int count = 0; o:m:9d
n  
//是否结束while循环 AM,@BnEcuT  
boolean breakWhile = false; .{~ygHQ`f  
}KJ/WyYW  
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while(!bStop) UtY<R  
{ H!HkXm"  
write_nPos(); tXwnK[~x  
Utility.sleep(500); `
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breakWhile = true; |7%M:7Q  
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for(int i=0;i<nStartPos.length;i++) P3);R>j  
{ km.xy_v  
if(!fileSplitterFetch.bDownOver) v"\Q/5p  
{ Q_]O[Kx  
breakWhile = false; jg' 'T1)  
break; 0lY.z$V  
} b1E>LrL  
} "rBo?%:  
if(breakWhile) !y `wAm>n  
break; eCdMDSFO3  
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//count++; NmVc2V]I  
//if(count>4) mam|aRzd  
// siteStop(); rC$ckug  
} B!yAam#^  
>4b-NS/}0  
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System.err.println("文件下载结束！"); ,\xeNUZd  
} 8.F]&D0p8  
catch(Exception e){e.printStackTrace ();} cC b'z1  
} P
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//获得文件长度 n:x6bPal]  
public long getFileSize() NqVe{+1x  
{ m<hR Lo  
int nFileLength = -1; /a(xUm@.  
try{ e%u1O-*  
URL url = new URL(siteInfoBean.getSSiteURL()); QzCu$ [  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [C.Pzo  
httpConnection.setRequestProperty("User-Agent","NetFox"); {H=DeQ  
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int responseCode=httpConnection.getResponseCode(); R=_ fk  
if(responseCode>=400) f@]4udc e  
{ 'OK)[\  
processErrorCode(responseCode); t9;yyZh  
return -2; //-2 represent access is error Yx>=(B  
} 7`thM/fN  
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String sHeader; _r^Cu.[7  
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for(int i=1;;i++) 2aNCcZw0  
{ 37Q9goMov  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z4b<$t[u  
//Utility.log(in.readLine()); 4U(W~O  
sHeader=httpConnection.getHeaderFieldKey(i); A|Up>`QH  
if(sHeader!=null) {|9x*I  
{ @rB!47!  
if(sHeader.equals("Content-Length")) -NGY+
1  
{ M[g9D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 82O#Fe q  
break; TO ^}z  
} pdUrVmW"'  
} FZ)_WaqGf  
else <DxUqCE  
break; 2^'|[*$k1@  
} .v?Ir)  
} \#?n'qyj  
catch(IOException e){e.printStackTrace ();} !yI , ~`Z  
catch(Exception e){e.printStackTrace ();} NifzZEX  
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Utility.log(nFileLength); ^rO3B?_  
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return nFileLength; .'.#bH9K  
} cy%JJ)sf  
_ +q.R  
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//保存下载信息（文件指针位置） (U#4j 6Q  
private void write_nPos() A%qlB[!:  
{ Dl_y[9  
try{ Y]!8Ymuww@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -!zyit5B  
output.writeInt(nStartPos.length); e@}zp  
for(int i=0;i<nStartPos.length;i++) ~M7 J{hK  
{ !#wd~: H  
// output.writeLong(nPos); x%Ivd  
output.writeLong(fileSplitterFetch.nStartPos); BU |]4  
output.writeLong(fileSplitterFetch.nEndPos); o&g-0!"  
} ~"6/OJA  
output.close(); \D
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} )FVW/{NF@q  
catch(IOException e){e.printStackTrace ();} ,Wtod|vx\U  
catch(Exception e){e.printStackTrace ();} n%yMf!M .:  
} |E/U(VS3l~  
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//读取保存的下载信息（文件指针位置） X
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private void read_nPos() zX*+J"x  
{ MLf,5f;e  
try{ f4eLnY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gBBS}HF  
int nCount = input.readInt(); DlIy'@ .  
nStartPos = new long[nCount]; Pp.qDkT  
nEndPos = new long[nCount]; R-CFF  
for(int i=0;i<nStartPos.length;i++) "N\>v#>C  
{ }A
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nStartPos = input.readLong(); =iF}41a  
nEndPos = input.readLong(); [+dOgyK  
} v,qK=]ty  
input.close(); DY<Br;  
} Huzw>
 
catch(IOException e){e.printStackTrace ();} OT/*|Pn9  
catch(Exception e){e.printStackTrace ();} 8JvF4'zx  
} H~y 7o_tg  
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private void processErrorCode(int nErrorCode) ^wDZg`  
{ $w!;~s  
System.err.println("Error Code : " + nErrorCode); AT.WXP0$A  
} N&ZIsaK,j  
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BCN
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//停止文件下载 QJ1_LJ4)a  
public void siteStop() u xif-5  
{ ,QW>M$g{  
bStop = true; g!%C_AI   
for(int i=0;i<nStartPos.length;i++) G,,c,  
fileSplitterFetch.splitterStop(); rWk4)+Tk  
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} *p
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} p<%76H A  
//负责部分文件的抓取 <~ E'% 60;  
**FileSplitterFetch.java m E<n=g=  
*/ m<]b]FQ  
package NetFox; ^}nz^+R  
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import java.io.*; [;O 6)W  
import java.net.*; Ji%6/zV  
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public class FileSplitterFetch extends Thread { z=q   
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String sURL; //File URL &}sC8,Sr  
long nStartPos; //File Snippet Start Position 0>PO4WFVJ  
long nEndPos; //File Snippet End Position &Z Ja}5k!r  
int nThreadID; //Thread's ID ?Uz7($}  
boolean bDownOver = false; //Downing is over 'J*)o<%  
boolean bStop = false; //Stop identical QvB]?D#h  
FileAccessI fileAccessI = null; //File Access interface tTa" JXG  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qSj$0Hq5XI  
{ p_z_d6?  
this.sURL = sURL; ZUE?19GA  
this.nStartPos = nStart; ^'"sFEV7RN  
this.nEndPos = nEnd; WR;"^<i9  
nThreadID = id; 9n][#I)a3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &gIDcZ  
} f#9DU}2m  
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public void run() N"d*pi#h  
{ 6fxf|R\  
while(nStartPos < nEndPos && !bStop) 9r@T"$V#c  
{ P(N$U^pj  
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try{ `9%Q2Al  
URL url = new URL(sURL); Mq7d*
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [;5?=X,LD  
httpConnection.setRequestProperty("User-Agent","NetFox"); e[D'0L
 
String sProperty = "bytes="+nStartPos+"-"; >{_`J  
httpConnection.setRequestProperty("RANGE",sProperty); "],amJ  
Utility.log(sProperty); gwFHp.mE  
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 %trtP  
InputStream input = httpConnection.getInputStream(); TRQX#))B  
//logResponseHead(httpConnection);  lZ^UAFF  
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byte[] b = new byte[1024]; ;jb+x5t  
int nRead; 'IrwlS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \]AsL&  
{ [&mYW.O<  
nStartPos += fileAccessI.write(b,0,nRead); E&G_7->  
//if(nThreadID == 1) 5x/q\p-{/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q+4
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} nLZT3`@~,  
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#^IEQZgH  
Utility.log("Thread " + nThreadID + " is over!"); 9HI9([Cs  
bDownOver = true; wA`A+Z2*?  
//nPos = fileAccessI.write (b,0,nRead); Dim,HPx]d  
} "Q*Z?6[Z  
catch(Exception e){e.printStackTrace ();} hM*T{|y  
} mUi|vq)`=D  
} sePOW#|  
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5p&&EA/  
//打印回应的头信息 G $u:1&  
public void logResponseHead(HttpURLConnection con) maANxSzi  
{ F*WWv&\X  
for(int i=1;;i++) qcxq-HS2'  
{ |q$br-0+  
String header=con.getHeaderFieldKey(i); 7. y L>  
if(header!=null) A/NwM1z[o)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "yMr\jt~-  
Utility.log(header+" : "+con.getHeaderField(header)); 6"Tr$E  
else 64s9Dy@%F  
break; ~g2ColFhu  
} 7{oG4X!  
} }-
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public void splitterStop() rnxO2   
{ 7`3he8@ze  
bStop = true; BaIh,iu  
} ["N>Po  
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} :SSlUl4sU$  
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/* LQYT/  
**FileAccess.java }#@P
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*//文件访问(定位，写) O'JH=
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package NetFox; 8<u_ wt@  
import java.io.*; ~S Js2-2  
di6A.N5A  
8}p5MG  
public class FileAccessI implements Serializable{ st36xS  
qv3L@"Ub  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DSix(bs9  
RandomAccessFile oSavedFile; 7<{Zq8)  
long nPos; 6<A\U/  
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public FileAccessI() throws IOException Ov%9S/d  
{ /B!"\0G/,  
this("",0); \~nUk7.  
} nLkC-+$tM  
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ox {Cm  
public FileAccessI(String sName,long nPos) throws IOException O*oL(dk*8L  
{ :i*JlKHJd  
oSavedFile = new RandomAccessFile(sName,"rw"); cd}TDd(H%  
this.nPos = nPos; V]}/e!XK
\  
oSavedFile.seek(nPos); #UU}lG  
} >'^l>FPc  
+
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public synchronized int write(byte[] b,int nStart,int nLen) O3*Vilx  
{ -tx)7KV-  
int n = -1; L~V 63K  
try{ DC*|tHl  
oSavedFile.write(b,nStart,nLen); h bj^!0m  
n = nLen; {NE;z<,*:  
} Uk ?V7?&  
catch(IOException e) oTOe(5N8a  
{ D]b5*_CT  
e.printStackTrace (); 4E3HY
Z  
} A'|W0|R9  
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oB3>0Pm*a.  
return n; 2ok>z$Y  
} ..;LU:F  
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} %8 cFzyE*  
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hUGIy(  
/* G`|mP:T:o  
**SiteInfoBean.java KUH&_yCRB  
*/ )X\3bPDJR  
package NetFox;  wSV[nK  
_* 4 <  
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public class SiteInfoBean { TdD-#|5  
!0Xes0gK0  
3 ;.{ O%bX  
private String sSiteURL; //Site's URL Jc9SHCJ  
private String sFilePath; //Saved File's Path #_7}O0?c3  
private String sFileName; //Saved File's Name {yVi/*;f^  
private int nSplitter; //Count of Splited Downloading File D (qT$#  
-lSm:O@'  
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public SiteInfoBean() ZWf{!L,@Z  
{//nSplitter的缺省值为5 .(9IAAwKn  
//default value of nSplitter is 5 e%'9oAz  
this("","","",5); cx_"{`+e  
} tvRa.3  
0e vxRcrzz  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0?,EteR  
{ .M:,pw"S]  
sSiteURL= sURL; *
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sFilePath = sPath; i8HSYA  
sFileName = sName; ~,':PUkiV  
this.nSplitter = nSpiltter; %I Y-0\  
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} f.+e  
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{!oO>t  
public String getSSiteURL() Y]8l]l 1  
{ E? F @  
return sSiteURL; _rjCwo\  
}  |k 4+I  
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public void setSSiteURL(String value) (:T~*7/"  
{ Kq!n`@  
sSiteURL = value; =Z-.4\3  
} i-E&Y*\^9H  
)J#@L*  
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public String getSFilePath() JI\u -+BE  
{ vgE5(fJh  
return sFilePath; ,u]kZ]  
} fn
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{8I
93]  
public void setSFilePath(String value) 2?-}(F;Z  
{ 8CEy#%7]}  
sFilePath = value; A;kAAM  
} )_bXKYUX*0  
Ii|<:BW  
}P}l4k1W  
public String getSFileName() p3x(:=
 
{ ?6j@EJ<2q  
return sFileName; \D}/tz5~B  
} c1n? @L  
7CG_UB  
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public void setSFileName(String value) Ld`~^<B  
{ SKG_P)TnO  
sFileName = value; 7%w4?Nv3I  
} m?B@VDZ  
?+Qbr$]  
(x=NA )  
public int getNSplitter() Mu:*(P/  
{ &x=<>~Ag
3  
return nSplitter; ,hOJe=u46  
} 7?hCt  
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public void setNSplitter(int nCount) U_I'Nz!^t  
{ = )(;  
nSplitter = nCount; L YH9P-5H  
} >J8?n,*  
} EKoCm)}d  
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'Z&A5\~  
/* ?=4J  
**Utility.java iSFgFJG^  
*/ r2&{R!Fj`  
package NetFox; 3{$cb"5  
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@[JQCQ#r  
public class Utility { rq
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public Utility() V@Po}  
{ N$=<6eQm  
fYCAwS{  
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} Vx#xq#wK  
iWtWT1n8n  
//线程睡眠 E|^a7-}|  
public static void sleep(int nSecond) 9'4cqR  
{ ~sA}.7  
try{ mX2Qf8  
Thread.sleep(nSecond); ;2X1qw>  
} xSLN  
catch(Exception e) wL%>  
{ zizrc.g/Yg  
e.printStackTrace (); 0q62{p7  
} TAGqRYgi  
} &_-~kU1K^  
1P[!B[;c  
//日志 4s$))x9p  
public static void log(String sMsg) da2BQ;  
{ FNm8j#c~Q  
System.err.println(sMsg); ;#j/F]xG  
} Y}Qu-fm  
}S42.f.p  
7v\OS-  
public static void log(int sMsg) M=!x0V;  
{ (oTx*GP>Y  
System.err.println(sMsg); ]AfeaU'>  
} %Y!lEzB5  
} Y*7.3 +#  
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/ ?Q@Pn  
/* U1&m-K  
**TestMethod.java AalyEn&>  
*/ pWQ?pTh  
package NetFox; (2a~gQGD  
"2Ye\#BU6  
D%BV83S   
public class TestMethod { fC81(5  
61wGIN2,  
u/,m2N9cL  
public TestMethod() jNB-FVaT  
{ ///xx/weblogic60b2_win.exe +i K.+B  
try{ ,':?3| $c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O"{NHNG\oT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M\T6cN@m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sM-k,0z  
fileFetch.start(); ,>e<mphM  
} &0N 3 p  
catch(Exception e){e.printStackTrace ();} y|1-,u.$  
#&$4tTl  
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} M'[J0*ip  
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public static void main(String[] args) :@n e29,}  
{ /)v X|qtIY  
new TestMethod(); ZgzrA&6  
} *!B,|]wq=  
} .Z9Bbab:  
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