http断点续传简单实现（java)

/* h;A~:}c,  
**SiteFileFetch.java `bWc<
4T  
*/ g`4WisL1n  
package NetFox; dw'P =8d  
import java.io.*; \_7'f  
import java.net.*; XpPcQIM*  
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public class SiteFileFetch extends Thread { Ss:'HH4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @]L$eOV_  
long[] nStartPos; //开始位置 3?TUt{3g  
long[] nEndPos; //结束位置 JY%l1:}G3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ? 3oUkGfn  
long nFileLength; //文件长度 J)sOne  
boolean bFirst = true; //是否第一次取文件 79B+8= K  
boolean bStop = false; //停止标志 C|]Zpn#{K  
File tmpFile; //文件下载的临时信息 u$qazj  
DataOutputStream output; //输出到文件的输出流 Y6a9S`o  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }S{VR(i`J  
public SiteFileFetch(SiteInfoBean bean) throws IOException lYU?j|n  
{ df/7u}>9  
siteInfoBean = bean; zUWeOR'X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SPnW8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0> QqsQ  
if(tmpFile.exists ()) 9{%/I   
{ [-^xw1:  
bFirst = false; =-avzuy#  
read_nPos(); WfQZ7e  
} <&HHo>rl  
else K14v6d  
{ n{=Ot^ ";  
nStartPos = new long[bean.getNSplitter()]; /< Dtu UM  
nEndPos = new long[bean.getNSplitter()]; ?y,KN}s_  
} [_*?~  
l0E]#ra"  
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} zek>]l`!  
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public void run() Ac\e>N  
{ r+tHVh  
//获得文件长度 [buLo*C4:  
//分割文件 +kq+x6&  
//实例FileSplitterFetch fFXnD  
//启动FileSplitterFetch线程 9&s>RJ  
//等待子线程返回 J2k4k  
try{ 28j/K=0(  
if(bFirst) vZPBjloT!.  
{ WsT  
nFileLength = getFileSize(); W)L*zVj~  
if(nFileLength == -1) pz"}o#R"x  
{ - x;xQ  
System.err.println("File Length is not known!"); n^<J@uC  
} fM"&=X  
else if(nFileLength == -2) :g{ybTSEe  
{ >b8-v~o{  
System.err.println("File is not access!"); ]$U A5/a  
} K*M1$@5  
else UDPn4q  
{ h r6?9RJY  
for(int i=0;i<nStartPos.length;i++) (UZ].+)s  
{ Sx1OY0)s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EIF  
} \/-4jF:  
for(int i=0;i<nEndPos.length-1;i++) *]c~[&x5&  
{ NMzq10M=6  
nEndPos = nStartPos[i+1]; PoLk{{l3  
} :.(A,  
nEndPos[nEndPos.length-1] = nFileLength; Z7k ku:9  
} r-a0XNS*  
} {9{PU&?(  
ei~f1$zc#h  
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//启动子线程 w17CZa 6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; { PS0.UZ  
for(int i=0;i<nStartPos.length;i++) mdlMciP  
{ vSo1WS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *hh9
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r6I
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nStartPos,nEndPos,i); :es=T`("A8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cv;#8Wj}  
fileSplitterFetch.start(); JD9
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} N;4wbUPL7h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @S 0mNA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CtZOIx.;|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \5j#ad  
nEndPos = " + nFileLength); #$l:%  
// fileSplitterFetch[nPos.length-1].start(); >` u8(  
0qW"b`9R  
,o}CBB! k  
//等待子线程结束 AuY*x;~  
//int count = 0; \uZ1Sl  
//是否结束while循环 EXR6Vb,  
boolean breakWhile = false; u(8dsgR  
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while(!bStop) 4~2 9,  
{ t_+owiF)M  
write_nPos(); B_RF)meux  
Utility.sleep(500); 
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breakWhile = true; lHE \Z`  
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for(int i=0;i<nStartPos.length;i++) yE;S6 O  
{ j}
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if(!fileSplitterFetch.bDownOver) ^FZ9q  
{ +^%)QH>9   
breakWhile = false; KL"_h`UW  
break; 6q,CEm  
} (px3o'lsh  
} ^2i$AM1t  
if(breakWhile) 7cO1(yE#vr  
break; @.,'A[D!K  
5nK|0vv%2  
!Wy&+H*0  
//count++; mn(MgJKQ\  
//if(count>4) ANR611-a  
// siteStop(); )P|/<>z  
} V1A7hRjxvG  
&m{~4]qWpM  
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System.err.println("文件下载结束！"); "*KOU2}
C  
} "AIS6%,  
catch(Exception e){e.printStackTrace ();} d8WEsQ+)A  
} &fnfuU$  
|r4&@)  
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//获得文件长度 VotI5O $  
public long getFileSize() $$R->  
{ 8:]5H}Hi  
int nFileLength = -1; lg@q} ]1  
try{ 5^Lb
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URL url = new URL(siteInfoBean.getSSiteURL()); Q?'Ax"$D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bf[l4$3k  
httpConnection.setRequestProperty("User-Agent","NetFox"); GB}X
 
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int responseCode=httpConnection.getResponseCode(); Ge24Lp;Y6  
if(responseCode>=400) o/!a7>xO4  
{ W\e!rq  
processErrorCode(responseCode); Nt[&rO3s  
return -2; //-2 represent access is error 0IsnG?"  
} 54f?YR  
/|<0,ozoJ  
@2\UjEo~  
String sHeader; jQ(%LYX$  
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for(int i=1;;i++) zf^@f%R  
{ 6|1#Prj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n>%TIoY  
//Utility.log(in.readLine()); eT8h:+k  
sHeader=httpConnection.getHeaderFieldKey(i); ,qhv(  
if(sHeader!=null) *yW9-(  
{ +R31YR8C0  
if(sHeader.equals("Content-Length")) ZaFqGcS~  
{ eh3CVgH91;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 11JO[  
break; a0 w  
} ?\a';@h  
} ,Nev7X[0  
else {1GIiP-U  
break; XP65  
} ";59,\6  
} u?8e>a  
catch(IOException e){e.printStackTrace ();} puGy`9eKv1  
catch(Exception e){e.printStackTrace ();} -} +PE 4fh  
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Utility.log(nFileLength); >Wj8[9zf  
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return nFileLength; M]e _@:!  
} l,Ixz1S3e  
*Rj*%S  
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//保存下载信息（文件指针位置） ;'|t>'0_  
private void write_nPos() glWa?#1  
{ /A`Lyp#  
try{ YZp]vlm~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3a,7lTUuB  
output.writeInt(nStartPos.length); i)d'l<RA  
for(int i=0;i<nStartPos.length;i++) hC2Ra "te)  
{ 8f#&CC!L  
// output.writeLong(nPos); No)@#^  
output.writeLong(fileSplitterFetch.nStartPos); @nF#\  
output.writeLong(fileSplitterFetch.nEndPos); |Oe$)(`|h  
} <1E*wPm8  
output.close(); rjT!S1Hs  
} 4_?*@L1  
catch(IOException e){e.printStackTrace ();} <' b%  
catch(Exception e){e.printStackTrace ();} u|E9X[%  
} 3)qtz_,H/g  
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//读取保存的下载信息（文件指针位置） gOA]..lh  
private void read_nPos() *AN2&>Y  
{ jo
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try{ {2%@I~US  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _{'HY+M  
int nCount = input.readInt(); G(y@Tor+  
nStartPos = new long[nCount]; Nc:>]  
nEndPos = new long[nCount]; las|ougLy  
for(int i=0;i<nStartPos.length;i++) dD"o~iEC  
{ (g]J hG  
nStartPos = input.readLong(); uEkUK|
 
nEndPos = input.readLong(); gkNvvuQXc  
} $+ ?A[{JG
 
input.close(); }\!38{&  
} C$$lJ=>  
catch(IOException e){e.printStackTrace ();} [z`m`9Aq  
catch(Exception e){e.printStackTrace ();} }c*6|B@f  
} *HN0em  
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private void processErrorCode(int nErrorCode) AZYu/k  
{ ySwvj
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System.err.println("Error Code : " + nErrorCode); #N"K4@]{  
} c>RS~/Y  
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//停止文件下载 p,+$7f1S  
public void siteStop() w">p 8  
{ u4[3JI>  
bStop = true; &llp*< i7  
for(int i=0;i<nStartPos.length;i++) -kd_gbnr3  
fileSplitterFetch.splitterStop(); I 0}+}{M:  
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{!hA^[}|  
} /Hl]$sJY  
} ZO $}m?  
//负责部分文件的抓取 @cZNoD  
**FileSplitterFetch.java 0SBiMTm  
*/ ye)CfP=ID\  
package NetFox; k%Q>lf<e   
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import java.io.*; g2WDa'{L  
import java.net.*; v/BMzVi  
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public class FileSplitterFetch extends Thread { 6 2r%q^r`i  
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String sURL; //File URL ^\uj&K6l  
long nStartPos; //File Snippet Start Position eJrJ5mlI`  
long nEndPos; //File Snippet End Position )MZQ\8,)]  
int nThreadID; //Thread's ID xhIC["z5  
boolean bDownOver = false; //Downing is over 6*/o  
boolean bStop = false; //Stop identical p`3pRrER  
FileAccessI fileAccessI = null; //File Access interface (!U5B Hnd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException joh=0nk;D  
{ F.b;O :  
this.sURL = sURL; J:,>/')n  
this.nStartPos = nStart; ~/6m|k  
this.nEndPos = nEnd; EwcN$Ma  
nThreadID = id; Brh<6Btl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V Z[[zYe  
} $*bd})y)I  
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public void run() 37wm[Z  
{ Z;aQ/n[`  
while(nStartPos < nEndPos && !bStop) ;Bo{.91
6  
{ I%43rdoPe  
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try{ !+4}x;!8  
URL url = new URL(sURL); fo$iV;x`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n)w@\Uyc  
httpConnection.setRequestProperty("User-Agent","NetFox"); *
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String sProperty = "bytes="+nStartPos+"-"; /s>ZT8vaAs  
httpConnection.setRequestProperty("RANGE",sProperty); sY=fS2b#)  
Utility.log(sProperty); _'k?9eN`  
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InputStream input = httpConnection.getInputStream(); h5G>FPM-=  
//logResponseHead(httpConnection); xQa[bvW  
+!6C^G  
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byte[] b = new byte[1024]; 1o7 pMp=  
int nRead; /H=fK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )FM
/^  
{ 3VbQDPG  
nStartPos += fileAccessI.write(b,0,nRead); ip4:px-  
//if(nThreadID == 1) C26PQGo#$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^.F@yo2}  
} g83!il\  
]BU,*YaB  
ik77i?Hg  
Utility.log("Thread " + nThreadID + " is over!"); MPMJkL$F
^  
bDownOver = true; $WvI%r  
//nPos = fileAccessI.write (b,0,nRead); rp.S4;=Q9  
} >b#z o,  
catch(Exception e){e.printStackTrace ();} qx<`Kc4  
} lztPexyXZ  
} lcij}-z:%e  
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2>#Pt^R:C  
//打印回应的头信息 wHk4BWg-  
public void logResponseHead(HttpURLConnection con) 2f>lgZ!  
{ ^u#!Yo.!(  
for(int i=1;;i++) TSmuNCR  
{ eP-q[U?$n  
String header=con.getHeaderFieldKey(i); -c!{'
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if(header!=null) 8w~I(2S:#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~zFs/(k  
Utility.log(header+" : "+con.getHeaderField(header)); Zgo^M,g  
else zr?%k]A%UO  
break; v
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} fR}|CP  
} M ]W'>g)G  
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public void splitterStop() b5 YE4h8%  
{
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bStop = true; J[;c}  
} FGBPhH% (8  
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} ts3%cRN r  
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/* dfGdY"&  
**FileAccess.java ZPn`.Qc  
*//文件访问(定位，写) ]v@#3,BV  
package NetFox; x&tad+T  
import java.io.*; C<2vuZD  
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mQBq-;  
public class FileAccessI implements Serializable{ 3Ec5:Caz  
m,$oV?y>j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ck2O?Ne  
RandomAccessFile oSavedFile; uh%%MhTjv  
long nPos;
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public FileAccessI() throws IOException xj)*K
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{ ,:G.V  
this("",0); 3k5OYUk  
} "8J$7g@n@  
 |X`xJL  
:
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public FileAccessI(String sName,long nPos) throws IOException /}r%DND'  
{ \y{Bnp5h  
oSavedFile = new RandomAccessFile(sName,"rw"); 9M:wUYHT  
this.nPos = nPos; HQK%Y2S  
oSavedFile.seek(nPos); gAC}  
} !E,$@mvd  
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public synchronized int write(byte[] b,int nStart,int nLen) NTuS(7m  
{ BQmg$N,F  
int n = -1; zht^gOs  
try{ U2=5Nt5  
oSavedFile.write(b,nStart,nLen); wt[MzpRP  
n = nLen;
%F9%t  
} zFqH)/  
catch(IOException e) &4sUi K"  
{ ej47'#EY  
e.printStackTrace (); /d9I2~}B  
} c~b[_J)  
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)?joF)  
return n; <w(
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} ;#P@(ZVT  
"X g@X5BG  
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} RD_&m?d  
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dY68wW>d|  
/* OqtQLqN  
**SiteInfoBean.java 4Z"DF)+}  
*/ ^q_0(Vf  
package NetFox; 1]aM)},  
mQtGE[  
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public class SiteInfoBean { (]^
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private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path +'2Mj|d@p  
private String sFileName; //Saved File's Name gpVZZ:~  
private int nSplitter; //Count of Splited Downloading File Yvs)H'n=  
*4Y1((1k
 
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public SiteInfoBean() ZOK2BCoW  
{//nSplitter的缺省值为5 f{FW7T}O2  
//default value of nSplitter is 5 y/h~oGxy  
this("","","",5); {*ATY+  
} wAkpk&R  
g+t-<D"L5  
e3"GC_*#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Yw"o_  
{ }L>}_NV\  
sSiteURL= sURL; @X?DHLM  
sFilePath = sPath; OGh9^,v  
sFileName = sName; eZIqyw  
this.nSplitter = nSpiltter; 3haYb`  
W~aVwO'(  
^](sCE7  
} Zk__CgS#  
/T]2ZX>  
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public String getSSiteURL() /@X!  
{ 
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return sSiteURL; 5'd$TC  
} 0=#:x()e  
cKdn3 2Y4  
X#'DS&{  
public void setSSiteURL(String value) L/_h5Q:'W  
{ F$ShhZgi  
sSiteURL = value; V$VqYy9 *  
} ?>cx;"xF  
LdwWB `L  
ri1D*CS  
public String getSFilePath() zR6,?Tzg  
{ ('xIFi  
return sFilePath; zUXQl{  
} I'HPy.
PV  
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public void setSFilePath(String value) N9tH0  
{ x2=Bu#Y  
sFilePath = value; x^Q:U1  
} P}29wrIZ  
bGOOC?[UX  
/W1!mih  
public String getSFileName() t6m3lq{  
{ Bha#=>4FU  
return sFileName; '#!nK O2<  
} y^zII5|s  
U>w#`Sy[  

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public void setSFileName(String value) }(A`aB_  
{ yG)xsY V  
sFileName = value; Xyy;BO:  
} n^B9Mh@  
3}(6z"r  
1)pwR3(^Fz  
public int getNSplitter() r&oR|-2hRk  
{ GK.^Gd  
return nSplitter; 4~xKW2*`K  
} k\BJs@-  
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g"ha1<y<  
public void setNSplitter(int nCount) r*HbglB  
{ #%N v\g;  
nSplitter = nCount; p4GhT~)l:  
} Z^E>)!t  
} #V&
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=!)Ye:\Q  
/* )UbPG`x8  
**Utility.java TwlX'iI_;  
*/ vT~ey
 
package NetFox; i)y8MlC{  
3n;>k9{  
3}dTbr4y  
public class Utility { i0
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k#F |  
public Utility() s|F}Ab
x,^  
{ })W9=xO~  
<|Srbs+  
"@^Pb$BLY  
} %]
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*N>n5B2  
//线程睡眠 Q2yD4>qy  
public static void sleep(int nSecond) eyW8?:  
{ $`j%z@[g  
try{ W*S}^6ZT`  
Thread.sleep(nSecond); [NE|ZL~  
} \ vn!SO7  
catch(Exception e) -Zq\x'  
{ R !g'zS'  
e.printStackTrace (); m%zo? e  
} `_aX>fw  
} ICck 0S!  
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//日志 C7*n<+e  
public static void log(String sMsg) :I_p4S.)  
{ JLd-{}A""-  
System.err.println(sMsg); Gyx4}pV  
} /tm2b<G  
n(I,pF  
"DaE(S&
 
public static void log(int sMsg) "&Hr)yyWG  
{ 37apOK4+  
System.err.println(sMsg); #($~e|  
} r{>Q{$Q  
} UE9RrfdN  
W(pq_H'  
.~$!BWP  
/* {p\ll  
**TestMethod.java  I~T   
*/ IiU\}<O  
package NetFox; EfX\"y  
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%
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public class TestMethod { umT *  
9|D*}OY>  
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public TestMethod() I(<9e"1O  
{ ///xx/weblogic60b2_win.exe Az7 ]qb  
try{ Su/8P[q_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {W+IUvn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )ifjK6*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :FTx#cZ  
fileFetch.start(); XHU\;TF  
} GCf,Gfmr  
catch(Exception e){e.printStackTrace ();} vA3wn><  
dx@|M{jz'  
Mj&G5R~_  
} s$%t2UaV  
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public static void main(String[] args) za%gD  
{ 8)lrQvZ  
new TestMethod(); |v:oLgUdH  
} )J*M{Gm6i  
} H*j!_>W  
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