http断点续传简单实现（java)

/* c^gIK1f-  
**SiteFileFetch.java ~*]`XL.-  
*/ ^b. MR?
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package NetFox; j;'Wf[V  
import java.io.*; Z6@J-<u  
import java.net.*; 'yjH~F.  
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public class SiteFileFetch extends Thread { Rw8m5U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZTC1t_  
long[] nStartPos; //开始位置 V *y  
long[] nEndPos; //结束位置 |CqJ2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L umD.3<  
long nFileLength; //文件长度 <&Xq`i/(  
boolean bFirst = true; //是否第一次取文件 7V``f:#d  
boolean bStop = false; //停止标志 FQ1oqqr  
File tmpFile; //文件下载的临时信息 *lF%8k"Al  
DataOutputStream output; //输出到文件的输出流 .g?,:$`0D?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） WN1-J(x6  
public SiteFileFetch(SiteInfoBean bean) throws IOException C P v}A  
{ o@;_(knb  
siteInfoBean = bean; <t@*[Aw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ID+k`nP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Mwk_SCy  
if(tmpFile.exists ()) cBf{R^>Fd  
{ ^C|9K>M  
bFirst = false; 8{t&8Ql n  
read_nPos(); 6u;(R0n  
} umn^QZ,  
else
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{ `:O.g9  
nStartPos = new long[bean.getNSplitter()]; @!O{>`  
nEndPos = new long[bean.getNSplitter()]; Z"T(8>c;g  
} r0bPaAKw  
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} - Sgp,"a  
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public void run() A@'W $p?5r  
{ E=trJge  
//获得文件长度 ^uzVz1%mM  
//分割文件 1`\kXaG  
//实例FileSplitterFetch Mp=+*I[  
//启动FileSplitterFetch线程 3s`3}DKK  
//等待子线程返回 /=}vPey  
try{ VNXVuM )c  
if(bFirst) nP31jm+A  
{ .CpO+z  
nFileLength = getFileSize();
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if(nFileLength == -1) X\RTHlw']  
{ hZJqo +s  
System.err.println("File Length is not known!"); "r+<=JU>OV  
} 1X.1t^HH:  
else if(nFileLength == -2) hDsORh!i  
{ czRh.kz,  
System.err.println("File is not access!"); AFED YRX  
} 
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else 4*W7{MPY  
{ 4iW2hV@m  
for(int i=0;i<nStartPos.length;i++) fh<G&E8 p  
{ bnQO}G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .5xg;Qg\Y  
} =1capix 1r  
for(int i=0;i<nEndPos.length-1;i++) $0t %}DE  
{ gs>cx]>  
nEndPos = nStartPos[i+1]; ~!kbB4`WK  
}
;v\n[  
nEndPos[nEndPos.length-1] = nFileLength; N/VIP0Kb  
} -Ma"V  
} tEs$+b  
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//启动子线程 xd@DN;e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p<e~x/@m*  
for(int i=0;i<nStartPos.length;i++) A[bxxQSP\H  
{ A?zW!
'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CG;D(AWR;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a06DeRCej  
nStartPos,nEndPos,i); oMbCljUC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rg~CF<  
fileSplitterFetch.start(); Xv:IbM> Qc  
} swrd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M-gjS6c\3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8>9+w/DL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ui&$/%Z|  
nEndPos = " + nFileLength); X;NTz75  
// fileSplitterFetch[nPos.length-1].start(); %54![-@  
~T~v*'_h  
#v-!GK_<  
//等待子线程结束 p%-9T>og  
//int count = 0; ?da3Azp  
//是否结束while循环 p'*UM%@SIY  
boolean breakWhile = false; 9iE66N>z  
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xa  
7F4]EA^  
while(!bStop) rpmDr7G  
{ !w Bmf&=  
write_nPos(); .$iIr:Tc>  
Utility.sleep(500); U|nk86r  
breakWhile = true; i}19$x.D`  
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for(int i=0;i<nStartPos.length;i++) 1F|+4  
{ nC^'2z  
if(!fileSplitterFetch.bDownOver) uM8gfY)OI  
{ '\Ub*m((1O  
breakWhile = false; Qp
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break; F`u~Jx8.*  
} y(
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} O]>`B
{  
if(breakWhile) C0RwW??t  
break; \2jY)UrQs  
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//count++; q}jf&xUWzH  
//if(count>4) $((<le5-)  
// siteStop(); ZE^de(Fm  
} '<Gqu_-  
@j6D#./7j  
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System.err.println("文件下载结束！"); xph60T
  
} heWb(E&  
catch(Exception e){e.printStackTrace ();} ,l6W|p?ZO^  
} d\v _!
7  
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//获得文件长度 w
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public long getFileSize() ,#G@ri:B  
{ Z=|@76  
int nFileLength = -1; _OY;SJ(  
try{ 5IMH G%W7  
URL url = new URL(siteInfoBean.getSSiteURL()); E !8y|_(j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NmQ]qv  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9O"?T7i"#  
 J{y@ O  
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int responseCode=httpConnection.getResponseCode(); G\Me%{b#  
if(responseCode>=400) P(`IY+  
{ JI&>w-~D  
processErrorCode(responseCode); Ij+zR>P8=\  
return -2; //-2 represent access is error Fv9Z'#t  
} 'Khq!pC   
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String sHeader; CbZ1<r" /  
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for(int i=1;;i++) fAs:[  
{  51j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bbJa,}R  
//Utility.log(in.readLine()); yS*PS='P  
sHeader=httpConnection.getHeaderFieldKey(i); <LJ$GiU  
if(sHeader!=null) 4Qv|Z+$i  
{ `Ao:}  
if(sHeader.equals("Content-Length")) t`AD9 H"\!  
{ N]duv~JS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CqoL5qt  
break; J
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} EY>A(   
} '.=Z2O3p  
else L8W3Tpi&(  
break; `G'V9Xs(  
} vZ08/!n  
} 4Z_.Jdu w  
catch(IOException e){e.printStackTrace ();} gvC2\k{  
catch(Exception e){e.printStackTrace ();} -4Xr5j%o  
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Utility.log(nFileLength); _VlNZ/V  
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return nFileLength; %;<FfS  
} c_iF S  
\c]/4C +/  
& zG=  
//保存下载信息（文件指针位置） ;[xDc>&("Q  
private void write_nPos() 8.,Pg
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{ SBEJ@&iB~  
try{ nXN0~,+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eYagI  
output.writeInt(nStartPos.length); I$Z"o9"  
for(int i=0;i<nStartPos.length;i++) +|.#<]GA  
{ iJYr?3nw;  
// output.writeLong(nPos); F JzjS;  
output.writeLong(fileSplitterFetch.nStartPos); Di
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output.writeLong(fileSplitterFetch.nEndPos); t3M/ThIE  
} , ?%`Ky/  
output.close(); TX>;2S3q  
} b &JPLUr  
catch(IOException e){e.printStackTrace ();} gFKQm(0g2  
catch(Exception e){e.printStackTrace ();} Qu\E/T`  
} p;@PfhEz)  
; etH)  
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//读取保存的下载信息（文件指针位置） '~@WJKk  
private void read_nPos() yqK82z5U*R  
{ /'
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try{ <W?,n%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 
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int nCount = input.readInt(); y>G{GQ  
nStartPos = new long[nCount]; r
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nEndPos = new long[nCount]; K|B1jdzL  
for(int i=0;i<nStartPos.length;i++) gs!{'=4wT  
{ [J^,_iN[.  
nStartPos = input.readLong(); v}!,4,]:&  
nEndPos = input.readLong(); cq0jM;@d  
} k@Hu0x  
input.close(); &8;mcM//4  
} #C+0m`  
catch(IOException e){e.printStackTrace ();} Rl,B !SF  
catch(Exception e){e.printStackTrace ();} $]Q_x?  
} 'g^]ZTxb  
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private void processErrorCode(int nErrorCode) X)yTx8v4  
{ lu>>~vy6  
System.err.println("Error Code : " + nErrorCode); ]\jhtC=2  
} J@Li*Ypo  
vH?/YhH|  
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//停止文件下载 P`"dj@1'  
public void siteStop() 9@h>_1RJz  
{ qYpHH!!C=  
bStop = true; x[vX|oE!A  
for(int i=0;i<nStartPos.length;i++) ^)SvH  
fileSplitterFetch.splitterStop(); GJ*AyYG  
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} >uQ!B
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} 9u:MF0:W  
//负责部分文件的抓取 {_ #   
**FileSplitterFetch.java 74KFsir@  
*/ 9oaq%Sf  
package NetFox; H fRxgA@  
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import java.io.*; }x%"Oq|2]x  
import java.net.*; 5X  
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public class FileSplitterFetch extends Thread { akNJL\b  
v.\&gn(  
 ztTpMj  
String sURL; //File URL E&97;VH  
long nStartPos; //File Snippet Start Position !Zs;m`j&9  
long nEndPos; //File Snippet End Position ?56Zw"89  
int nThreadID; //Thread's ID >z(6ADq  
boolean bDownOver = false; //Downing is over =B;)h  
boolean bStop = false; //Stop identical ~:JKXa?  
FileAccessI fileAccessI = null; //File Access interface 08'JT{iid  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ln3
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{ M]6=Rxq1:E  
this.sURL = sURL; r"0nUf*og:  
this.nStartPos = nStart; r*WdD/r|  
this.nEndPos = nEnd; R+^/(Ws'<  
nThreadID = id;
w("jyvV[C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #|'8O  
} #Q;#A |EZ  
YN\ QwV  
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public void run() :\.v\.wm  
{ `_f3o,5  
while(nStartPos < nEndPos && !bStop) H#1/H@I#  
{ C#gQJ=!B  
~>C!l 
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try{ )>=`[$D1t  
URL url = new URL(sURL); hwexv 9""  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vv zd>yII  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6H3_qx  
String sProperty = "bytes="+nStartPos+"-"; z9VQsC'K  
httpConnection.setRequestProperty("RANGE",sProperty); P{);$e+b~  
Utility.log(sProperty); yLI=&7/e@  
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InputStream input = httpConnection.getInputStream(); u]zb<)'_  
//logResponseHead(httpConnection); 9%)'QDVGLf  
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byte[] b = new byte[1024]; ka]n+"~==\  
int nRead; y{kXd1,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dso\+s  
{ hR. EZ|.  
nStartPos += fileAccessI.write(b,0,nRead); PUa~Apj'  
//if(nThreadID == 1) |=7%Edkd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "+|>nA=7  
} 4h(aTbHaQ  
<@Ew-JU  
?lbX.+  
Utility.log("Thread " + nThreadID + " is over!"); }
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bDownOver = true; *aTM3k)Zs  
//nPos = fileAccessI.write (b,0,nRead); k5<lkC2z  
} {V
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catch(Exception e){e.printStackTrace ();} 5Lue.U%a  
} 8l?]UFM>C  
} TN l$P~X>  
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//打印回应的头信息 Wqy8ZgSC  
public void logResponseHead(HttpURLConnection con) bG\1<:6B  
{ {0e5<"i  
for(int i=1;;i++) !vG._7lPp  
{ >.B+xn=  
String header=con.getHeaderFieldKey(i); 6.ap^9AD  
if(header!=null) YP#OI6u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qHvW{0E  
Utility.log(header+" : "+con.getHeaderField(header)); ph69u #Og  
else
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break; L5U>`lx6$  
} bk5~t'  
} sX@e1*YE_  
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public void splitterStop() F.AO  
{
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bStop = true; '"I"D9;9  
} O1/!)E!  
4
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} c-gaK\u}j}  
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/* {9P<G]Z  
**FileAccess.java Q}I.UG_  
*//文件访问(定位，写) ;M}bQ88  
package NetFox; 2Q<_l*kk(  
import java.io.*; jQf1h|e  
\*_qP*vq@  
0
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public class FileAccessI implements Serializable{ heRQ|n.Dz)  
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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 Av/|={i  
RandomAccessFile oSavedFile; .k[Ptx>  
long nPos; ^QXUiXzl  
|Z!C`G[  
 E?%k  
public FileAccessI() throws IOException 'zRd?Z>%  
{ w}7`Vas9  
this("",0); w/ZV9"BhE  
} g%^Zq"  
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public FileAccessI(String sName,long nPos) throws IOException rJZ-/]Xf!6  
{ [D/q%  
oSavedFile = new RandomAccessFile(sName,"rw"); 3`-[95w  
this.nPos = nPos; |n]^gTJt  
oSavedFile.seek(nPos); oq;}q  
} tXfB.[U  
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8B\,*JGY2  
public synchronized int write(byte[] b,int nStart,int nLen) 3):7mE(  
{ qB"y'UW8  
int n = -1; i"_JF-IbN  
try{ r\L:JTZ$  
oSavedFile.write(b,nStart,nLen); GVFD_;j'  
n = nLen; 23+>K  
} _pk=IHGsB  
catch(IOException e) ,![C8il,  
{ JB**z00;  
e.printStackTrace (); y:pypuwt;  
} 'O2{0  
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return n; 8CMI\yk  
} >>&~;PG[  
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}8 ,b;Q  
} !'n+0  
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cj5pI?@e)  
/* :qw:)i  
**SiteInfoBean.java \b~zyt6-  
*/ vE{QN<6T  
package NetFox; %lEPFp  
YIjBKh  
NcqE)"yObo  
public class SiteInfoBean { ca$D|3  
R?^FO:nM%!  
uy7)9w  
private String sSiteURL; //Site's URL V@T G"YF  
private String sFilePath; //Saved File's Path sE]eIN  
private String sFileName; //Saved File's Name `5h$@  
private int nSplitter; //Count of Splited Downloading File 8=t?rA  
vR#A7y @!  
Y|KX:9Y@  
public SiteInfoBean() 5wr0+Xo  
{//nSplitter的缺省值为5 sp'q=^t  
//default value of nSplitter is 5 '(I"54W  
this("","","",5); &zUo",}9  
} (9'MdH  
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W._vikR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (S1$g ~t;  
{ m_U__CZ}Tt  
sSiteURL= sURL; g'hBs D1'  
sFilePath = sPath; uV=rLDY  
sFileName = sName; P0UMMn\-#  
this.nSplitter = nSpiltter; awo=%vJ&  
b(K.p?bt  
3{~hRd  
} nL@P{,J  
hg=\L5R  
_d)w, ;m#  
public String getSSiteURL() O^|,Cbon6  
{ C+O`3wPZp  
return sSiteURL; `7+?1z  
} vy6NH5Q  
>0B[  
5v!Uec'+  
public void setSSiteURL(String value) KmpX^Se[  
{ NS<lmWx+  
sSiteURL = value; V/J[~mN9  
} \fh.D/@  
]TqcV8Q~  
h.=YAcR0D  
public String getSFilePath() 9sJbz=o]r  
{ 2{#*z%|z  
return sFilePath; m6aoh^I  
} -mcLT@  
C[<&%=  
:cIE8<\%  
public void setSFilePath(String value) v"y e\ZG  
{ Y~gpiL3u  
sFilePath = value; vAU^<$D27  
} Qa(u+  
}+I 8l'  
t55CT6Se  
public String getSFileName() w{#%&e(q"  
{ 6R dfF$f
 
return sFileName; ()3+!};  
} 2 R1S>X  
j&[63XSe  
4hZ-^AL"(  
public void setSFileName(String value) :IbrV@gN{@  
{ Xgr|~(^  
sFileName = value; R# mZYg  
} 0Rrz   
z[] AH#h  
es&+5  
public int getNSplitter() oa1&9  
{ l&U3jeW-o  
return nSplitter; eHd{'J<  
} [uZU p*.V  
/>.&  
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public void setNSplitter(int nCount) mpK|I|-  
{ t[)z/[m  
nSplitter = nCount; (;C_>EL&u  
} \MK)dj5uUJ  
} .#rI9op  
'HPw5 L  
#d(6q$IE  
/* XlDVJx<&J  
**Utility.java V>4 !fD=  
*/ /.7x[Yc  
package NetFox; [Z~>7ayF+)  
z&cfFx#h)  
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public class Utility { >Py;6K  
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+- c#UO
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public Utility() qt/"$
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{ <$,iYx  
8t9sdqM/C  
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} &hjrJ/'^  
~sMn/T*fv  
//线程睡眠 VO. Y\8/  
public static void sleep(int nSecond) Ya304Pjd  
{ DCP"  
try{ (J$JIPF  
Thread.sleep(nSecond); 3l5q?"$  
} 2Xe2%{  
catch(Exception e) d=N5cCqq  
{ _S@s  
e.printStackTrace (); dpGaI  
} Hagj^8  
} ?8YHz  
zSDiJ$Xk  
//日志 >d#B149  
public static void log(String sMsg) ;(VJZ_
 
{ M/Bn^A8@  
System.err.println(sMsg); pd>EUdbrp&  
} BU]9eF!>h  
@*A(#U8p3  
O_(J',++  
public static void log(int sMsg) 1B,RRHXn6  
{ Kd7OnU  
System.err.println(sMsg); Ca?pK_Y  
} AO>K 6{  
} C0KP,JS&  
*kZJ  
ikyvst>O  
/* *RN*Bh|$  
**TestMethod.java P0}uTee  
*/ ]5rEwPB  
package NetFox; RrKs!2sCT  
u+XZdV  
-%%2Pz0I  
public class TestMethod { N@;6/[8  
r|?2@VE  
[eG- &u  
public TestMethod() > YN<~z-  
{ ///xx/weblogic60b2_win.exe Tet,mzVuu  
try{ YNk?1#k?i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,f}s!>j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fvN2]@:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); is#?O5:2  
fileFetch.start(); kmo3<'
j{  
} {Qlvj.Xw  
catch(Exception e){e.printStackTrace ();} \>:(++g  
k@KX=mG<  
]5uCs[  
} 6Dw[n   
~;Xdz/  
.NwHr6/s*  
public static void main(String[] args) y;sr# -L  
{ 0'RSl~QvqS  
new TestMethod(); 4*
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} \u",bMQF  
} 6dq5f?w]  
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