http断点续传简单实现（java)

/* lJ2/xE]  
**SiteFileFetch.java *)sz]g|d  
*/ eesLTyD2_  
package NetFox; >}tG^)os  
import java.io.*; m$j;FKz+|  
import java.net.*; R9HS%O6b6  
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public class SiteFileFetch extends Thread { -B! TA0=oJ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WWzns[$f  
long[] nStartPos; //开始位置 oMf h|B  
long[] nEndPos; //结束位置 l$@lk?dc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y$W3\`2q  
long nFileLength; //文件长度 ZPFTNwf  
boolean bFirst = true; //是否第一次取文件 q&x#S
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boolean bStop = false; //停止标志 "lAS <dq  
File tmpFile; //文件下载的临时信息 FV,SA3  
DataOutputStream output; //输出到文件的输出流 mjc:0hH  
2)]*re)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [^P2Kn  
public SiteFileFetch(SiteInfoBean bean) throws IOException iIRigW  
{ !7|9r$  
siteInfoBean = bean; BE;iC.rW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ou4?`JF)-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1@
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if(tmpFile.exists ()) x/v+7Pt_  
{ 2?&ptN)`N  
bFirst = false; `84yGXLK  
read_nPos(); x$4'a~E  
} =i<(hgD  
else )^3655mb  
{ o*8 pM`uw  
nStartPos = new long[bean.getNSplitter()]; W{2y*yqY  
nEndPos = new long[bean.getNSplitter()]; .w"O/6."  
} breVTY7 S  
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} 3"RZiOyv  
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public void run() (.)s =  
{ 8=VX` X  
//获得文件长度 '!GI:U+g  
//分割文件 [Y+
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//实例FileSplitterFetch W;yZ$k#q}(  
//启动FileSplitterFetch线程 ;B@l0)7(x  
//等待子线程返回 @[lr F7`o  
try{ 1k(*o.6  
if(bFirst) m\Nc}P_"p  
{ w=
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nFileLength = getFileSize(); g Q^]/X  
if(nFileLength == -1) =@
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{ 6UTdy1Qq>  
System.err.println("File Length is not known!"); s4*,ocyBP  
} ^\;5O(9  
else if(nFileLength == -2) <taW6=;c  
{ 
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System.err.println("File is not access!"); ggWfk  
} dDn:^)  
else 4G2V{(@QiZ  
{ \v_(*  
for(int i=0;i<nStartPos.length;i++) A5\S0l$Q  
{ Z]CH8GS~<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h[?28q$  
} +/'jX?7x%  
for(int i=0;i<nEndPos.length-1;i++) +g&W423k_  
{ jHzb,&
  
nEndPos = nStartPos[i+1]; wq#3f#3V  
} 9 R1]2U$|  
nEndPos[nEndPos.length-1] = nFileLength; 4B 6Aw?  
} mB`r6'#=  
} c{q`uI;O  
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//启动子线程 1lM0pl6M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oB@C-(M  
for(int i=0;i<nStartPos.length;i++) h !1c(UR  
{ {I ,
'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g*uO IF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1d6pQ9 N  
nStartPos,nEndPos,i); |ouk;r24V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uw!v=n3#!  
fileSplitterFetch.start(); WF7RMQ51j  
} J0k~%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kp|reKM/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5;*C0m2%i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k-/$8C  
nEndPos = " + nFileLength); uVocl,?.L  
// fileSplitterFetch[nPos.length-1].start(); y{<7OTA)  
O1"!'Gk[!L  
' wEP:}  
//等待子线程结束 ]n_A~Yr  
//int count = 0; wl4yNC  
//是否结束while循环 S/|8'x{<  
boolean breakWhile = false; eAj}/2y"  
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@\a- =  
while(!bStop) idq= US  
{ QK\z-'&n  
write_nPos(); }Z|a?J@CZm  
Utility.sleep(500); slbV[xR  
breakWhile = true; ~F-,Q_|-  
>JhQ=j  

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for(int i=0;i<nStartPos.length;i++) - U|4`{PP  
{
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if(!fileSplitterFetch.bDownOver) (~~=<0S  
{ //(c 1/s  
breakWhile = false; .6*A~%-=[d  
break; v3B ^d}+.  
} h?b{{  
} 9b0Z Ey{  
if(breakWhile) NZ#z{JI=+  
break; e)M1$  
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|N*>K a;  
//count++; sYL+;(#t  
//if(count>4) =J,:j[D(  
// siteStop(); C^a~)r.h  
} MB)xL-jO  
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System.err.println("文件下载结束！"); Z-p_hNb  
} \Z$*8z=  
catch(Exception e){e.printStackTrace ();} n~h%K7 c  
} @AwH?7(b  
|7argk+  
AQ&;y&+QR  
//获得文件长度 Pz?O_@Ln  
public long getFileSize() :JlJB  
{ eNNK;xXe#  
int nFileLength = -1; zK&`&("4C  
try{ Je/R'QP^8  
URL url = new URL(siteInfoBean.getSSiteURL()); 1DX=\BWp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TS;MGi0`}  
httpConnection.setRequestProperty("User-Agent","NetFox"); y~\z_') <>  
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int responseCode=httpConnection.getResponseCode(); z)ydQw>  
if(responseCode>=400) ms?
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{ ]k hY8it  
processErrorCode(responseCode); V\ |b#?KL  
return -2; //-2 represent access is error 09F
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} 7-^d4P+|g  
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String sHeader; xN5}y3  
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for(int i=1;;i++) _jtBU  
{ milU,!7J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z:w7e0  
//Utility.log(in.readLine()); "Kqe4$  
sHeader=httpConnection.getHeaderFieldKey(i); NTV0DkX  
if(sHeader!=null) %bAv.'C  
{ \t}!Dr+yN  
if(sHeader.equals("Content-Length")) bNXT*HOZb3  
{ `18G 5R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $+tkBM  
break; m^wYRA.  
} qwN-VCj  
} VL\6U05Z  
else |2mEowAd  
break; BM3nZ<%3  
} !Ed';yfz\(  
} k]v a  
catch(IOException e){e.printStackTrace ();} hgm`6TQ  
catch(Exception e){e.printStackTrace ();} Uu G
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Utility.log(nFileLength); @Fo0uy\G  
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return nFileLength; K\uR=L7  
} FsD}Nk=m~  
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=ahD'*R^A  
//保存下载信息（文件指针位置） *b> ~L  
private void write_nPos() X@TQD  
{ )s!x)< d;  
try{ ]]Wa.P~]O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =|H/[",gg  
output.writeInt(nStartPos.length); $} ~:x_[  
for(int i=0;i<nStartPos.length;i++) |W?x6]~.R  
{ I&4|T<j  
// output.writeLong(nPos); mp}ZHufG  
output.writeLong(fileSplitterFetch.nStartPos); "BK&C6]  
output.writeLong(fileSplitterFetch.nEndPos); t/HE@xPxI5  
} )jnxR${M  
output.close(); ,<%],-Lt[  
} O<fbO7.-  
catch(IOException e){e.printStackTrace ();} 9'}m797I'  
catch(Exception e){e.printStackTrace ();} q
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} PQ1\b-I  
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//读取保存的下载信息（文件指针位置） ?k#-)inf)  
private void read_nPos() =xg pr*   
{ DT;Hr4Z8^"  
try{ ^IY1^x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ._#|h5  
int nCount = input.readInt(); p^NYJV  
nStartPos = new long[nCount]; UDhW Y.`'~  
nEndPos = new long[nCount]; 5X'[{'i,  
for(int i=0;i<nStartPos.length;i++) #k*e>d$  
{ fZ$8PMZv  
nStartPos = input.readLong(); ;4%^4<+3  
nEndPos = input.readLong(); >AJtoJ=j  
} jrG@ +" }  
input.close(); I
X$ $pdQ  
} 't2"CPZ  
catch(IOException e){e.printStackTrace ();} klv ]+F&[  
catch(Exception e){e.printStackTrace ();} //g~1(  
} Vc}m_T]O  
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)~s(7 4`}  
private void processErrorCode(int nErrorCode) y~jTI[kS  
{ L=?Yc*vg  
System.err.println("Error Code : " + nErrorCode); }m(u oT~  
} &*r YY\I  
&?v^xAr?B  
+!CG'qyN>  
//停止文件下载 [.;VCk)0x  
public void siteStop() EX=Q(}9F<  
{ nTyKZ(#u  
bStop = true; Od)]FvO  
for(int i=0;i<nStartPos.length;i++) )Yy`$`  
fileSplitterFetch.splitterStop(); ?tSFM:9PU  
 5'Y @c  
}qRYXjS  
} bR(rZu5  
} {O[a+r.n  
//负责部分文件的抓取 N.l+9L0b  
**FileSplitterFetch.java b~z1%?  
*/ ">j}!n 8J  
package NetFox; <%Bsb}h,  
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import java.io.*; I5 "Z  
import java.net.*; ?l &S:` L  
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public class FileSplitterFetch extends Thread { mY+Jju1  
P?\IlziCB  
B~G?&"]  
String sURL; //File URL nZ0- Kb
 
long nStartPos; //File Snippet Start Position W c{<DE?J  
long nEndPos; //File Snippet End Position fq48>"g*  
int nThreadID; //Thread's ID o+r?N5  
boolean bDownOver = false; //Downing is over IXDj;~GF  
boolean bStop = false; //Stop identical P{h;2b{  
FileAccessI fileAccessI = null; //File Access interface Mpzt9*7R  
qk<(iVUO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sB"Oi|#lk  
{ 7jQOwzj  
this.sURL = sURL; 4$oN
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this.nStartPos = nStart; n<+g{QHi  
this.nEndPos = nEnd; |Ah'KpL8W  
nThreadID = id; w^6rgCl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m0DD|7}+  
} %wzDBsX  
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public void run() G~5EAeG  
{ 1RgtZp%  
while(nStartPos < nEndPos && !bStop) D2z" Z@  
{ 7o_1PwKS6  
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try{ ?Z9C}t]  
URL url = new URL(sURL); _bRd2
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Uus%1hC%a  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?%-VSL>$w=  
String sProperty = "bytes="+nStartPos+"-"; Up*1j:_O  
httpConnection.setRequestProperty("RANGE",sProperty); Xn@\p5<  
Utility.log(sProperty); hLK5s1#K  
"%ou'\}  
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InputStream input = httpConnection.getInputStream(); O9?t,1  
//logResponseHead(httpConnection); A/ZZ[B-  
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byte[] b = new byte[1024]; AqnDsr!  
int nRead; )WuU?Tn&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6Lj=%&  
{ ,j E'd'$  
nStartPos += fileAccessI.write(b,0,nRead); Fjch<gAofS  
//if(nThreadID == 1) &\),V1"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }-4@EC>  
} zW.I7Z0^  
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Utility.log("Thread " + nThreadID + " is over!"); R!{^qHb  
bDownOver = true; Zq1ZrwPF  
//nPos = fileAccessI.write (b,0,nRead); B?n 6o|8  
} O=m_P}K  
catch(Exception e){e.printStackTrace ();} v%
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} utOATjB.z  
} pn"TFapJA  
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//打印回应的头信息 \vwsRT 1  
public void logResponseHead(HttpURLConnection con) eYNu78u   
{ 6bPoC$<Z  
for(int i=1;;i++) w1U2cbCr/  
{ ~C M%WvS  
String header=con.getHeaderFieldKey(i); 9bu}@#4*  
if(header!=null) XK#~w:/fB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h.T]J9;9  
Utility.log(header+" : "+con.getHeaderField(header)); q9+`pj  
else y#tuwzE  
break; zNG]v?JAh  
} ',+YWlW  
} )bqSM&SO  
ufl[sj%^|  
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public void splitterStop() ZW+M<G  
{ (dvsGYT|.  
bStop = true; w8veh[%3n  
} H#/ #yVw  
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oW ! Z=;  
} n$Nb,/o  
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/* ''D\E6c\  
**FileAccess.java yBKEw(1  
*//文件访问(定位，写) s|HpN  
package NetFox; lB)%s~P:s  
import java.io.*; _L8|ZV./  
"2'4b  
;@ <E  
public class FileAccessI implements Serializable{ &BOq%*+  
K<3,=gL9[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iEx sGn]2  
RandomAccessFile oSavedFile; Sjb[v  
long nPos; vC#_PI  
fl@=h[g#t  
x)}.@\&%  
public FileAccessI() throws IOException &JUHm_wd&S  
{ fI<|]c}P&J  
this("",0); <b.O^_zQF  
} yj$a0Rgkv  
"%zb>`1s  
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public FileAccessI(String sName,long nPos) throws IOException t_xO-fT)  
{ S"=y>.#
 
oSavedFile = new RandomAccessFile(sName,"rw"); U~CG(9  
this.nPos = nPos;
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oSavedFile.seek(nPos); b;;mhu  
} 6Dl]d%
.  
C\`*_t  
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public synchronized int write(byte[] b,int nStart,int nLen) simD<&p  
{ ]S0tK  
int n = -1; ioW&0?,Ym  
try{ Z:(Zy
  
oSavedFile.write(b,nStart,nLen); ]nIH0k3y  
n = nLen; ;9&#Sb/  
} 6Mc&gnN  
catch(IOException e) Ot<vn34mt:  
{ y/vGt_^;3<  
e.printStackTrace (); xcHuH-}  
} 3aY^6&  
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return n; cM?i _m  
} F=g+R~F  
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} 'g5 Gdn  
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/* xfzGixA  
**SiteInfoBean.java < C1Jim  
*/ S"<"e\\}"_  
package NetFox; ?9Hs,J  

1 !8 b9  
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public class SiteInfoBean { t,]E5,1  
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private String sSiteURL; //Site's URL w<|Qezi3 w  
private String sFilePath; //Saved File's Path Z1dLC'/b]  
private String sFileName; //Saved File's Name VN/v]  
private int nSplitter; //Count of Splited Downloading File huat,zLS  
wZnv*t_  
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public SiteInfoBean() KD=W(\  
{//nSplitter的缺省值为5 ,9.-A-Yw  
//default value of nSplitter is 5 }7HR<%<7  
this("","","",5); qdNt2SO  
} +1pY^#A  
dX;Q\  ]"  
7=@3cw H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ri<'apl  
{ eEmuE H@X  
sSiteURL= sURL; 'D
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sFilePath = sPath; WV&grG|
 
sFileName = sName; V48o+O  
this.nSplitter = nSpiltter; PRi1 `%d  
Dt~ |)L+  
.|g|X8X  
} s&)>gE\  
i_{b*o_an  
%0Mvd;#[  
public String getSSiteURL() pd\x^F`sk.  
{ _`~\zzUZ  
return sSiteURL; efrVF5,y?  
} xT8pwTO  
D!WyT`T  
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public void setSSiteURL(String value) 9#MY(Hr  
{ -d)+G%{  
sSiteURL = value; B,(zp#&yB  
} S{fFpe-  
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public String getSFilePath() "CY#_)  
{ _Squ%z:D  
return sFilePath; b-OniMq~  
} GX#SCZ&}C  
=im7RgIBo  
J ?^
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public void setSFilePath(String value) xcM*D3  
{ OzA'd\|  
sFilePath = value; (iJ9ekB  
} 3aUWQP2  
J.Fy0W@+k4  
[4 y7tjar^  
public String getSFileName() rE?Fp
 
{ ,LodP%%UV  
return sFileName; U9(p ^  
} Hw1:zro  
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vAcxca">S  
public void setSFileName(String value) |w+N(wcJ  
{ Q4h6K7  
sFileName = value; FMEW['  
} k0@*Up3{7  
BN%;AQV  
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public int getNSplitter() Ym
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{ /Bs42uJ3  
return nSplitter; N9cCfB\`  
} G7NRpr  
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public void setNSplitter(int nCount) c
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{ b]6@ O8  
nSplitter = nCount; \(`8ng]vs  
} {,+MaH  
} 3L^]J}|  
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/* 9/#
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**Utility.java Xy]Pmt  
*/ yvIzgwN%s!  
package NetFox; T)o>U&KNP  
]114\JE  
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public class Utility { 1LVO0lT  
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public Utility() vf;&0j&`  
{ bae\EaS ?  
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svvl`|n%  
} M2!2J  
i`^[_  
//线程睡眠 RdqB^
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public static void sleep(int nSecond)
qV5lv-p  
{ hxZL/_n'  
try{ 0s!';g Q  
Thread.sleep(nSecond); {1;R&  
} p6X-P%s  
catch(Exception e) !:wA\mAd  
{ l05'/duuJ  
e.printStackTrace (); *!^l ZpF  
} 'h87A-\!F  
} 'YvRkWf:KC  
p(6KJK\  
//日志 D"M[}$P  
public static void log(String sMsg) N|e#&  
{ ?/q\S  
System.err.println(sMsg); 4o|<zn  
} KBa ]s q_  
F1u2SltR
 
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public static void log(int sMsg) Tfp^h~&u  
{ /m|U2rrqb  
System.err.println(sMsg); 7S2"e[-x  
} %
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} Ajm4q_
  
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:nS$cC0x*  
/* j;BlpRD}  
**TestMethod.java \l1==,wk  
*/ 1ne
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package NetFox; 0k G\9  
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a4&Aw7"X  
public class TestMethod { T^icoX=c4  
|B {*so]  
*RM
3_  
public TestMethod() L6./5`bs  
{ ///xx/weblogic60b2_win.exe ] @:x<>  
try{ =2@
V}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B \LmE+a>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SW}?y%~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `\$EPUM  
fileFetch.start(); MdDL?ev  
} \V#
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catch(Exception e){e.printStackTrace ();} oA?EJ~%  
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{zalfw{+  
} ;;|.qgxc~  
4L_)@n}  
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public static void main(String[] args) ZeqsXz  
{ E[cH/Rm  
new TestMethod(); u|cP&^S  
} Eh*(N(`  
} jG{OLF6 !  
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