http断点续传简单实现（java)

/* C:!&g~{cKi  
**SiteFileFetch.java .<K9Zyi  
*/ %Zeb#//Jz  
package NetFox; <0/)v J- 9  
import java.io.*; 8M4GforP  
import java.net.*; sldcI@Z  
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public class SiteFileFetch extends Thread { -Lsl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %~<F7qB  
long[] nStartPos; //开始位置 mt
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long[] nEndPos; //结束位置 eH;{Ln  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C]zG@O!  
long nFileLength; //文件长度 h-03]M#8=  
boolean bFirst = true; //是否第一次取文件 ;P8.U(  
boolean bStop = false; //停止标志 YRaF@?^Gn  
File tmpFile; //文件下载的临时信息 -ADb5-px  
DataOutputStream output; //输出到文件的输出流 C;Kq_/l  
"NV~lJS%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） f1\mE~#}  
public SiteFileFetch(SiteInfoBean bean) throws IOException P?=}}DI  
{
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siteInfoBean = bean; =EHKu|rX~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qz-lQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pW<l9W  
if(tmpFile.exists ()) ;A?86o'?  
{ :9|CpC`.  
bFirst = false; L3S29-T  
read_nPos(); C
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} |kHzp^S  
else 7Zh#7jiZ`  
{
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nStartPos = new long[bean.getNSplitter()]; U@".XIDQ  
nEndPos = new long[bean.getNSplitter()]; OV^?cA  
} tHJahK:"k  
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} x,<|<W5<%  
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public void run() e1H2w? s  
{ |Mnc0Fgvy,  
//获得文件长度 8$ _8Yva"e  
//分割文件 _.GH
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//实例FileSplitterFetch 0[-@<w ^j  
//启动FileSplitterFetch线程 `9DW}  
//等待子线程返回 p+F>+OQ*  
try{ DPWnvd  
if(bFirst) )5<c8lzp  
{ NV18~5#</  
nFileLength = getFileSize(); xf3/J{n3  
if(nFileLength == -1) &A&2z l %#  
{ \lpvRZ\L&g  
System.err.println("File Length is not known!"); 9!Bz)dJ3  
}  LII4sf]  
else if(nFileLength == -2) B5qlU4km&  
{ Tu=~iQ  
System.err.println("File is not access!"); z|m-nIM  
} %hA0  
else rW
2   
{ E>1%7" i<  
for(int i=0;i<nStartPos.length;i++) hhJ>>G4R2  
{ :
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); -aM7>YR  
} \~:_h#bW  
for(int i=0;i<nEndPos.length-1;i++) UmP\;
 
{ -pN'r/$3V  
nEndPos = nStartPos[i+1]; K^[Dz\ov5  
} MJcWX|(y  
nEndPos[nEndPos.length-1] = nFileLength; ?,UO$#Xm  
} `_.(qg   
} ej]>*n  
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Nj}-"R\u  
//启动子线程 bx3kd+J7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o+T,O+i  
for(int i=0;i<nStartPos.length;i++) g-2(W  
{ }\.Z{h:t ?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ga
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K]>X31Ho  
nStartPos,nEndPos,i); ~ll+/w\4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ByW,YKMy  
fileSplitterFetch.start(); k mX:~KMb  
} %H7H0%qW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]]V|]}<)m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aq]bF%7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KiMEd373-  
nEndPos = " + nFileLength); &}b-aAt  
// fileSplitterFetch[nPos.length-1].start(); g:[yA{
Eh  
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//等待子线程结束 Ehg(xK  
//int count = 0; i/q1>  
//是否结束while循环 'n7Ld6%1  
boolean breakWhile = false; 7HEUmKb"  
-h#9sl->  
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while(!bStop) \']_y\  
{ -hP>;~*4  
write_nPos(); ;c0z6E /  
Utility.sleep(500); w7Vl,pN,  
breakWhile = true; 1|H(q  
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for(int i=0;i<nStartPos.length;i++) Qg gx:  
{ +Am\jsq  
if(!fileSplitterFetch.bDownOver) KOVR=``"/  
{ R}0!F2  
breakWhile = false; 4w(#`'I>  
break; 8Rd*`]@[pk  
} (-hGb:  
} PG'+vl  
if(breakWhile) kTS#>uS  
break; m7.6;k.  
+{H
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//count++; P~ODd(  
//if(count>4) c>yqq'  
// siteStop(); //-;uEO  
} U<.,"`=l  
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System.err.println("文件下载结束！"); "1>48Z-UC  
} hd_<J]C  
catch(Exception e){e.printStackTrace ();} FKk.BA957h  
} T8-,t];i  
TCetd#;R  
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//获得文件长度 Ggp.%kS6F  
public long getFileSize() q;=!=aRg  
{ ]Qh0+!SdG  
int nFileLength = -1; NmZowh$M  
try{ _*LgpZ-2(  
URL url = new URL(siteInfoBean.getSSiteURL()); W60C$*h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +|TFxaVz  
httpConnection.setRequestProperty("User-Agent","NetFox"); RP~ hi%A  
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int responseCode=httpConnection.getResponseCode(); @_C?M5v  
if(responseCode>=400) p2uZ*sY(D  
{ oTLpq:9J  
processErrorCode(responseCode); y-#01Z  
return -2; //-2 represent access is error f,'9Bj.~  
} 1_6oM/?'  
KVZ-T1K  
2(K@V6j$M  
String sHeader; 8)51p+a
 
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for(int i=1;;i++) T6fm`uL&L  
{ T~-OC0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $I:&5o i  
//Utility.log(in.readLine()); Y>Tok|PV  
sHeader=httpConnection.getHeaderFieldKey(i); o=y0=,:a?9  
if(sHeader!=null) _"688u'88  
{ vOi4$I~CJ  
if(sHeader.equals("Content-Length")) Z@QJ5F1y  
{ ylwh_&>2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H&E3RU>`  
break; ^%jk.*  
} YK6zN>M}E  
} XX[CTh?O%  
else ERz{, >
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break; X>4qL'b:z  
} ?5jq)xd2  
} !pAb+6~T  
catch(IOException e){e.printStackTrace ();} |.Vs
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catch(Exception e){e.printStackTrace ();} L@>$ Aw  
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Utility.log(nFileLength); +jN%w{^=  
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return nFileLength; \ICc?8oL  
} y;xY74Nq  
8\B]!  
^M~Z_CQL2  
//保存下载信息（文件指针位置） mq6TwM  
private void write_nPos() Dwg_#GSr  
{ \:D"#s%x  
try{ u;3wg`e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <%GfF![v  
output.writeInt(nStartPos.length); >dYN@cB$}  
for(int i=0;i<nStartPos.length;i++) W~qVZ(G*U  
{ y';"tDFb  
// output.writeLong(nPos); K4K]oT  
output.writeLong(fileSplitterFetch.nStartPos); Z|6,*XEc   
output.writeLong(fileSplitterFetch.nEndPos); =Cg1I\  
} L wP  
output.close(); ['jr+gIfQ  
} -0f,qNF  
catch(IOException e){e.printStackTrace ();} Zj5B}[,l\  
catch(Exception e){e.printStackTrace ();} Ge+T[  
} ibn(eu<uW  
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//读取保存的下载信息（文件指针位置） M~,N~ N1  
private void read_nPos() &"'Z)iWm  
{ uN+]q qCf  
try{ Z+g9!
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q]hl+C$d"/  
int nCount = input.readInt(); 
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nStartPos = new long[nCount]; w:c9Z=KX  
nEndPos = new long[nCount]; Z,1b$:+  
for(int i=0;i<nStartPos.length;i++) ~>B`T%=H  
{ r}i}4
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nStartPos = input.readLong(); 45.Vr[FS.  
nEndPos = input.readLong(); 8~ wP?  
} pxb4x#CC  
input.close(); %:e.E
S  
} nN5fP<H2x  
catch(IOException e){e.printStackTrace ();} o9]i {e>L  
catch(Exception e){e.printStackTrace ();} "< })X.t  
} X;7hy0Y  
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private void processErrorCode(int nErrorCode) ODNZLCB~t  
{
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System.err.println("Error Code : " + nErrorCode); Pmdf:?B  
} Q:U>nm>xA  
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//停止文件下载 TX).*%f[r  
public void siteStop() N~~ sM"n  
{ hMnm>  
bStop = true; ;b_l/T(  
for(int i=0;i<nStartPos.length;i++) ?Sr7c|a2  
fileSplitterFetch.splitterStop(); >PK 6CR  
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]\m>N]P]  
} qPoN 8>.  
} bCqTubbx!t  
//负责部分文件的抓取  L30$  
**FileSplitterFetch.java 5 BLAa1  
*/ [,56oMd~  
package NetFox; TyY%<NCIb  
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import java.io.*; l1vI  
import java.net.*; DR7JEE  
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i ?PgYk&}  
public class FileSplitterFetch extends Thread { >!Dp'6
 
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<b:xyHS  
String sURL; //File URL bs0[ a 1/  
long nStartPos; //File Snippet Start Position F-Bj  
long nEndPos; //File Snippet End Position ==AmL]*  
int nThreadID; //Thread's ID pp@O6  
boolean bDownOver = false; //Downing is over '<{Jlz(u9  
boolean bStop = false; //Stop identical yw1-4*$c  
FileAccessI fileAccessI = null; //File Access interface a:Nf+t  
|]5`T9K@b#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0DnOO0Nc  
{ o!&+ _BKw  
this.sURL = sURL; Vo.~1^  
this.nStartPos = nStart; fo~*Bp()-E  
this.nEndPos = nEnd; WCk. K  
nThreadID = id; C1l'<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \"L0d1DK)  
} +T4}wm  
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public void run() ^B}q@/KV  
{ %<p/s;eu  
while(nStartPos < nEndPos && !bStop) 5eyB\>k,  
{ QUZ+#*:s  
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try{ bI(8Um6m  
URL url = new URL(sURL); <$Sl%
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O.\\)8xA  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4#:Eq=(W  
String sProperty = "bytes="+nStartPos+"-"; Jk7 Am-.0  
httpConnection.setRequestProperty("RANGE",sProperty); MZWv#;.]  
Utility.log(sProperty); 8^_e>q*W  
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InputStream input = httpConnection.getInputStream(); v046
 
//logResponseHead(httpConnection); R[*n3 wB  
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byte[] b = new byte[1024]; h qhX  
int nRead; 2 J3/Eu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ][#|5UK8L  
{ .RAyi>\e  
nStartPos += fileAccessI.write(b,0,nRead); H;q[$EUNb  
//if(nThreadID == 1) 6hcK%0z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @o#Yq n3Y  
} =1VZcLNt  
rQ2TPX<?a  
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Utility.log("Thread " + nThreadID + " is over!"); >#gDk K  
bDownOver = true; .N#KW  
//nPos = fileAccessI.write (b,0,nRead); vg"*%K$a  
} p=kt+H&;  
catch(Exception e){e.printStackTrace ();} suFk<^3  
} WIAukM8~  
} k{hNv|:,  
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""_G4{  
//打印回应的头信息 .yD 6$!6  
public void logResponseHead(HttpURLConnection con) l]Ym)QP  
{ 5j0 Ib>\  
for(int i=1;;i++) !h<O c!9  
{ }s6Veosl  
String header=con.getHeaderFieldKey(i); |YV> #l  
if(header!=null) e"{"g[b/7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {^:NII]  
Utility.log(header+" : "+con.getHeaderField(header)); Zu>-y#Bw  
else u86@zlzd  
break; 28c6~*Te#  
} I36%oA  
} 3)2{c  
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p&)d]oV>  
public void splitterStop() d+ZXi'  
{ cD)9EFo  
bStop = true; H5 :,hrZY  
} WU@_aw[  
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} N[fwd=$\
#  
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/* T/ eX7p1  
**FileAccess.java W2zG"Q  
*//文件访问(定位，写) ,`k6@4  
package NetFox; /(u? k%Q  
import java.io.*; VZ">vIRyi|  
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~F-lO1  
public class FileAccessI implements Serializable{ SXO.|"M  
I3'UrKKO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZitmvcMk  
RandomAccessFile oSavedFile; ~ISY( &  
long nPos; ZH>i2|W<  
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Zs-lN*u7.  
public FileAccessI() throws IOException (\r^0>H  
{ /0fHkj/J=B  
this("",0); L%<]gJtrO  
} ZJF+./vN  
`g)  
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public FileAccessI(String sName,long nPos) throws IOException HVhd#Q;  
{ UugR  
oSavedFile = new RandomAccessFile(sName,"rw"); K=}Eupn=  
this.nPos = nPos; v&d'ABeT  
oSavedFile.seek(nPos); 2mMi=pv9  
} ,=c(P9}^  
1CSGG'J]E  
]\oT({$6B  
public synchronized int write(byte[] b,int nStart,int nLen) 1;i|GXY:h  
{ 4GG>n  
int n = -1; =n_z`I  
try{ r:E4Wi{\  
oSavedFile.write(b,nStart,nLen); JP5en  
n = nLen; UIg?3J}R  
} jt: *Y  
catch(IOException e) 4<)*a]\c5M  
{ Z#(Y%6[u  
e.printStackTrace (); @'GPZpbvZ  
} F?6Q(mRl  
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return n; fo`R=|L[  
} , /jHhKW  
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} ],~[^0  
-1NR]#P'  
@g+v2(f2v  
/* 0
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**SiteInfoBean.java DHuvHK0#  
*/ 5} ur,0{  
package NetFox; <sM_zoprc  
?*r%*CL  
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public class SiteInfoBean { BYHyqpP9  
GM1.pVb  
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private String sSiteURL; //Site's URL Nh/i'q/  
private String sFilePath; //Saved File's Path &)JoB  
private String sFileName; //Saved File's Name \*qradgx$  
private int nSplitter; //Count of Splited Downloading File NjA[(8\:  
UJ%.KU%Q}  
6#K.n&=*  
public SiteInfoBean() ^,vFxN--q  
{//nSplitter的缺省值为5 !Fxn1Z,  
//default value of nSplitter is 5 +]NpcE'  
this("","","",5); Iw)m9h  
} T5e#Ll/  
R^sgafGl=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,/TmTX--d  
{ NZADHO@0  
sSiteURL= sURL; I|K!hQ"m  
sFilePath = sPath; :oC;.u<*8  
sFileName = sName; *8;<w~  
this.nSplitter = nSpiltter; ' S,g3  
gzH;`,  
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} `k8jFB C  
}NGP!  
x?u@ j7[  
public String getSSiteURL() S?a4IK  
{ iC^91!<  
return sSiteURL; w`+-xT%  
} v*.iNA;&i  
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x  
public void setSSiteURL(String value) C?]eFKS."  
{ MZcvr9y  
sSiteURL = value; Y8IC4:EO  
} vlZmmQeJm  
#Dz"g_d  
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public String getSFilePath()  cC|  
{ V*(x@pF  
return sFilePath; ahCwA}  
} fkX86  
iS<1C
`%>  
UWS 91GN@  
public void setSFilePath(String value) m-;8O /  
{ OT=1doDp  
sFilePath = value; ?MmQ'1N  
} )p>p3b g  
u>agVB4\F  
8\:>;XG6f  
public String getSFileName() +ug/%Iay{k  
{ Ygkf}n  
return sFileName; ?1Vx)j>|  
} T"C.>G'[B  
,)J>8eV  
(18ZEKk  
public void setSFileName(String value) jOGiT|A  
{ 1=sL[I7<  
sFileName = value; _dCDT$^&r  
} C"0 VOb  
)D'#>!Y  
be]/ROP>H  
public int getNSplitter() +t&)Z  
{ y:$qX*+9e  
return nSplitter; i;]# @n|  
} !Icznou\
  
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public void setNSplitter(int nCount) aj .7t=^  
{ mJ5%+.V  
nSplitter = nCount;
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} .'38^  
} PvjZoF["  
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|*h{GX.(  
/* |]?W`KN0  
**Utility.java 8f)pf$v`   
*/ fi~@J`  
package NetFox; )t7MD(  
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7 <]YK`a2d  
public class Utility {  n6Uf>5  
< ]+Mdy  
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public Utility() z-g6d(  
{ u(f;4`  
+|pYu<OY  
gae=+@z  
} 5T(
cy  
7,Z<PE  
//线程睡眠 ZHeq)5C ;f  
public static void sleep(int nSecond) ;/?w-)n?  
{ t>*(v#WeZ  
try{ NRT]dYf"z  
Thread.sleep(nSecond); Xppb|$qp4H  
} nec}g
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catch(Exception e) Z0y~%[1X  
{ g=qaq  
e.printStackTrace (); #=ij</  
} :5T=y @  
} kv+^U^WoU  
F  Qk  
//日志 2DJg__("  
public static void log(String sMsg) :(yut  
{ ]F>#0Rdc  
System.err.println(sMsg); eK*oV}U-k  
} K4]ZVMm/*  
5|Z8UzL  
UhkL=+PD  
public static void log(int sMsg) O#O"]A  
{ $ #GuV'  
System.err.println(sMsg); yuJ>xsM  
} ' ;nG4+K  
} ;E.f%  
n$7*L9)(C  
NW3qs`$-(  
/* 8+".r2*_iO  
**TestMethod.java \awkt!Wa  
*/ -Q?c'e  
package NetFox; 0a<h,s0"2  
D Y4!RjJ47  
Gx}`_[-  
public class TestMethod { r#&JfAo  

&V+KM"Ow  
T9]0/>  
public TestMethod() xFM^-`7  
{ ///xx/weblogic60b2_win.exe GJ2ZK=/  
try{ /'_<~A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (pP.*`JRv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _JTK$\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (aSuxl.Dq  
fileFetch.start(); zF{~Md1  
} K`<HZK  
catch(Exception e){e.printStackTrace ();} Pi9?l>  

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6Uq;]@k%  
} LayK&RwL  
4(oU88z  
;~d$OM  
public static void main(String[] args) >#l:
]T  
{ -%%Xx5D  
new TestMethod(); Sj|tR[SAoD  
} EEK!'[<,sE  
} pYr+n9)^  
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