http断点续传简单实现（java)

/* =A$5~op%  
**SiteFileFetch.java g`d5OHvOo  
*/ ; "ux{ .  
package NetFox; =;l.<{<VH  
import java.io.*; A Ns.`S  
import java.net.*; #OqQD6  
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public class SiteFileFetch extends Thread { Q0#oR[(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kl?U2A.=  
long[] nStartPos; //开始位置 re2M!m6k5  
long[] nEndPos; //结束位置 COH0aNp;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A0m  
long nFileLength; //文件长度 :"5
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boolean bFirst = true; //是否第一次取文件 n!2"pRIi  
boolean bStop = false; //停止标志 AME3hA  
File tmpFile; //文件下载的临时信息 )^qM%k8  
DataOutputStream output; //输出到文件的输出流 yAy~|1}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -y5^xR  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ur6UE2  
{ }%c2u/PQ  
siteInfoBean = bean; zflq|dW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O:IU|INq8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ai)S:2  
if(tmpFile.exists ()) f*,jhJ_I  
{ j1Fy'os"!  
bFirst = false; uUB,OmLN  
read_nPos(); umaF}}-Q{  
} Dq/_^a/1  
else '-oS=OrZ  
{ :.e`w#$7  
nStartPos = new long[bean.getNSplitter()]; N7Kq$G2O  
nEndPos = new long[bean.getNSplitter()]; 9]<p  
} i,r O3Jn  
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i ?&t@"'  
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} ,m;S-Im_Xr  
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public void run() tJ>%Xop  
{ N:?U
A  
//获得文件长度 GvSSi'q~B  
//分割文件 mk(O..)2  
//实例FileSplitterFetch 4y\qJw)~U  
//启动FileSplitterFetch线程 d[E~}Dq3#  
//等待子线程返回 }Qyuy~-&^  
try{ ~P8 6=Vw  
if(bFirst) 4QC"|<9R  
{ >L\$
  
nFileLength = getFileSize(); ,V1/(|[h  
if(nFileLength == -1) _0N=~`'  
{ 0zQ"5e?qy  
System.err.println("File Length is not known!"); \X.CYkgK  
} a\;1%2a  
else if(nFileLength == -2) ZG[P?fM  
{ 8mjPa^A  
System.err.println("File is not access!"); v%v(-, _q  
} '#RzX8|v<  
else 5b>-t#N,  
{ yY_(o]k  
for(int i=0;i<nStartPos.length;i++) XtY!fo*  
{ 3<}\{jT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +Ysm6n '  
} Fa<>2KkOr  
for(int i=0;i<nEndPos.length-1;i++) W!vN(1:(  
{ wNo2$>*  
nEndPos = nStartPos[i+1]; ,)/gy)~#  
} (3cJ8o>&  
nEndPos[nEndPos.length-1] = nFileLength; hgIqr^N9  
} Zk,` Iq  
} kt`_n+G  
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//启动子线程 )4:K@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; qTSyy=  
for(int i=0;i<nStartPos.length;i++) gZA[Sq
 
{ I|zak](HU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sB!#`kh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L7i2is  
nStartPos,nEndPos,i); ;iT@41)
7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v:\8  
fileSplitterFetch.start(); \9"  
} wcr3ugvT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W*J_PL9j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5Ku=Xzvq  
nEndPos = " + nFileLength); & -r^Q  
// fileSplitterFetch[nPos.length-1].start(); krqz;q-p~  
S!+c1q: ].  
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//等待子线程结束 h?_Cv*0q  
//int count = 0; `HVS}}{a  
//是否结束while循环 eTg8I/)%B  
boolean breakWhile = false; "/e_[_j  
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}9:(l  
while(!bStop) d}D%%noIu  
{ S]!s)q-- z  
write_nPos(); 1oKF-";u(  
Utility.sleep(500); .8o?`  
breakWhile = true; *vy^=Yea  
O
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for(int i=0;i<nStartPos.length;i++) F/pq9  
{ /ILj}g'  
if(!fileSplitterFetch.bDownOver) #jrtsv]  
{ Z9 z!YaOL  
breakWhile = false; )6+Z99w  
break; x
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} V52>K$j  
} @JW HG1qJ  
if(breakWhile) (g"
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break; 0gRj3al(  
8Z&M}Llk  
,LE
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//count++; G)|Xj70  
//if(count>4) *y+N-uq  
// siteStop(); 1G}f83yR  
} I+oe{#
:.  
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System.err.println("文件下载结束！"); T`?7z+2A  
} o*MiKgQ&  
catch(Exception e){e.printStackTrace ();} Xr:gm`[  
} yv[3&E?  
mpr_AL!ZO~  
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//获得文件长度 G2$<Q+UYs?  
public long getFileSize() jz,K>   
{ _0cCTQE  
int nFileLength = -1; A<h^.{  
try{ O2pntKI  
URL url = new URL(siteInfoBean.getSSiteURL()); qt(+X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); --fRhN>  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1d$qr`  
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int responseCode=httpConnection.getResponseCode(); ^ps6\>=0cW  
if(responseCode>=400) @4t_cxmD  
{ 7vo8lnQ{  
processErrorCode(responseCode); 4,,DA2^!  
return -2; //-2 represent access is error %p48=|+  
} _sb~eB~<(  
i:a*6b.U@N  
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String sHeader; @T"-%L8PL  
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for(int i=1;;i++) ^h$^j  
{ [vGkr" =  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O~Jm<  
//Utility.log(in.readLine()); u^O!5 'D%  
sHeader=httpConnection.getHeaderFieldKey(i); &4O2uEW0  
if(sHeader!=null) YpOcLxFL  
{ 5cvvdO*C0  
if(sHeader.equals("Content-Length")) H#S`m  
{ |(%=zb=?X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tk)JE^'  
break; xTU;rJV  
} yk0tA  
} pG6?"*Fz;  
else &SG5f[  
break; >'lvZt  
} $@D*/@  
} wBWqibY|  
catch(IOException e){e.printStackTrace ();} pCf9"LLer  
catch(Exception e){e.printStackTrace ();} YQ$LU\:  
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Utility.log(nFileLength); $>8O2p7W  
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return nFileLength; upLjkQ)_  
} XU`ly3!  
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~.tl7wKkR/  
//保存下载信息（文件指针位置） ^e]O-,UBk  
private void write_nPos() 0HO'%'Ga*  
{ csd9[=HW/Q  
try{ x8xz33  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <NEz{1Z  
output.writeInt(nStartPos.length); 85f:!p  
for(int i=0;i<nStartPos.length;i++) 5DpvMhc_  
{ !kG|BJ$j  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); v.&c1hKHb  
output.writeLong(fileSplitterFetch.nEndPos); dB)-qL8,2  
} 7KHQ0  
output.close(); uHsLlfTn  
} MK-+[K  
catch(IOException e){e.printStackTrace ();} i[?VF\Y(  
catch(Exception e){e.printStackTrace ();} nC%<BatQ  
} ]v/pMg#-  
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//读取保存的下载信息（文件指针位置） C hQ] d  
private void read_nPos()  y!dw{Lz  
{ 48Jt5Jz_  
try{ MgP&9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); No8-Hm  
int nCount = input.readInt(); d A'0'M  
nStartPos = new long[nCount]; y"Pd>61h  
nEndPos = new long[nCount]; K5rra%a-7  
for(int i=0;i<nStartPos.length;i++) P5
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{ `g_r<EY8/  
nStartPos = input.readLong(); m^\&v0  
nEndPos = input.readLong(); <-mhz`^  
} Y_}_)n
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input.close(); G!`PP  
} 9[`c"Pd  
catch(IOException e){e.printStackTrace ();} Lu~E5 ,  
catch(Exception e){e.printStackTrace ();} 6g\hQ\+Z}  
} ;[79Ewd#$  
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private void processErrorCode(int nErrorCode) op@=0d
??  
{ ?yxQs=&-q~  
System.err.println("Error Code : " + nErrorCode); )@p?4XsT4J  
} SA#01}&p  
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//停止文件下载 k+%&dEE|vH  
public void siteStop() ?(Ua+*b  
{ '7pzw>E=:  
bStop = true; RH:vd|q+  
for(int i=0;i<nStartPos.length;i++) qX`Hi9ja  
fileSplitterFetch.splitterStop(); }VRl L>HAC  
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|VzXcV-"8)  
} JQ;.+5 N<K  
} F\hVunPVx  
//负责部分文件的抓取 c:52pYf+  
**FileSplitterFetch.java c3Gy1#f:#2  
*/ L }3eZ-  
package NetFox; d``wx}#Uk  
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import java.io.*; QFnpp\K  
import java.net.*; qe'ssX;  
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public class FileSplitterFetch extends Thread { :5['V#(o  
Ozhn`9L+1!  
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String sURL; //File URL ?:M4GY"gV  
long nStartPos; //File Snippet Start Position [KFCc_:  
long nEndPos; //File Snippet End Position |V4<eF-0
S  
int nThreadID; //Thread's ID $.t>* Bq  
boolean bDownOver = false; //Downing is over mBJr*_p  
boolean bStop = false; //Stop identical D)pTE?@W'  
FileAccessI fileAccessI = null; //File Access interface >_xuXEslUz  

vBJxhK-  
dC8}Ttc}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *`|xa@1v`  
{ 3u/AqL  
this.sURL = sURL; \m~p;B  
this.nStartPos = nStart; *sZH3:  
this.nEndPos = nEnd; Z:<an+v|5  
nThreadID = id; -)B_o#2=2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?G,gP
b  
} .j
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public void run() FF#+d~$z  
{ ^<qi&*  
while(nStartPos < nEndPos && !bStop) t1U+7nM  
{ lz::6}  
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try{ <YtjE!2  
URL url = new URL(sURL); F~qZIggD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ll-QhcC$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7H?xp_D  
String sProperty = "bytes="+nStartPos+"-"; 4Ngp  -  
httpConnection.setRequestProperty("RANGE",sProperty); j}B86oX  
Utility.log(sProperty); ~,ozhj0f/  
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InputStream input = httpConnection.getInputStream(); \v6lcA
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//logResponseHead(httpConnection); <ShA_+Nd  
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byte[] b = new byte[1024]; },#7  
int nRead; p}h.2)PO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rX /'  
{ +
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nStartPos += fileAccessI.write(b,0,nRead); x~R,rb   
//if(nThreadID == 1) ;1PJS_@rX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j)Ak:l%a  
} JKfJ%yy |  
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Utility.log("Thread " + nThreadID + " is over!"); cV0CI&  
bDownOver = true; ,c^nW  
//nPos = fileAccessI.write (b,0,nRead); >p@b$po  
} ?>7-a~*A@  
catch(Exception e){e.printStackTrace ();} a*LfT<hmU3  
} 9(q(;|;Hp  
} #T2J +  
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//打印回应的头信息 8 /t';  
public void logResponseHead(HttpURLConnection con) '7PaJj=Nx  
{ G"E_4YkJ  
for(int i=1;;i++) >;hAw!|#  
{ J{prI;]K  
String header=con.getHeaderFieldKey(i); kyvl>I0q@  
if(header!=null) OR!W3 @  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ![_0GF
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Utility.log(header+" : "+con.getHeaderField(header)); xQDQgvwa  
else HnKgD:  
break; _fu <`|kc  
} bKGX> %-  
} ;s{'cN[.  
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public void splitterStop() 9$z$yGjl  
{ w-# f^#  
bStop = true; L;$>SLl,  
} ?#xm6oe#aH  
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} T:Nk9t$W7@  
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>@Ht*h{~  
/* qf\W,SM  
**FileAccess.java ?.%dQ0  
*//文件访问(定位，写) SU4i'o  
package NetFox; ]#^v754X^T  
import java.io.*; ]S[/a  
.
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public class FileAccessI implements Serializable{ Sk>=C0f:  
!|xB>d q?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t~j6wsx;  
RandomAccessFile oSavedFile; \q1tT!]  
long nPos; $1|E(d1  
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HrvyI)4{  
public FileAccessI() throws IOException WIf.;B)L  
{ [UI>SN  
this("",0); cI\[)5&  
} z5]6"v-  
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public FileAccessI(String sName,long nPos) throws IOException GIxs>E'X  
{ 0LH6G[  
oSavedFile = new RandomAccessFile(sName,"rw"); wCNn/%C  
this.nPos = nPos; {<gv1Yht  
oSavedFile.seek(nPos); >x;\H(g  
} aF^NYe  
94ruQ/   
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public synchronized int write(byte[] b,int nStart,int nLen) }8
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{ (vZ-0Ep}  
int n = -1; m =b7 r  
try{ Uc {m##!  
oSavedFile.write(b,nStart,nLen); 8R3{
YJ6@T  
n = nLen; xt?-X%oY8  
} .6C/,rQ?c  
catch(IOException e) 3;BIwb_  
{ =;uMrb4  
e.printStackTrace (); 7\2I>W  
} )8W! |  
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return n; ai sa2#  
} pvyEs|f=%  
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} u7hu8U=  
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} jJKE  
/* -9t"
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**SiteInfoBean.java mYgfGPF`  
*/ Mi8)r_l%O  
package NetFox; [cd1Mf:[Y  
+mVAmG@  
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public class SiteInfoBean { )xV37]  
]E<Z5G1HD  
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private String sSiteURL; //Site's URL O68-G   
private String sFilePath; //Saved File's Path JpfA+r  
private String sFileName; //Saved File's Name 49QsT5b)  
private int nSplitter; //Count of Splited Downloading File F*PhV|XU  
-/JEKwc  
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public SiteInfoBean() ?lsK?>uU  
{//nSplitter的缺省值为5 .u7}p#  
//default value of nSplitter is 5 xyGwYv>*KO  
this("","","",5); 34u[#O{2  
} cr!W5+r  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xOe1
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{ UGO;5!  
sSiteURL= sURL; XMI*obS'z  
sFilePath = sPath; bN. G%1  
sFileName = sName; O0#[hY,  
this.nSplitter = nSpiltter; |})s0TU  
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} _ l`F}v  
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public String getSSiteURL() -pYmM d,  
{ Ea@0>_U|  
return sSiteURL; f1_;da  
}  pRobx  
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public void setSSiteURL(String value) 8IlUbj  
{ $?PI>9g!  
sSiteURL = value; ?l9sj]^w  
} jV sH  
]
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public String getSFilePath() ..8t1+S6]  
{ #AGO~#aK  
return sFilePath; tw$EwNI[  
} J=3{<Xl  
4P3RRS  
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public void setSFilePath(String value) ~DK.Y   
{ uy<3B>3~.  
sFilePath = value; utZI'5i  
} M
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3HrG^/  
7p.8{zQ*  
public String getSFileName() ,zoHmV1Wd+  
{ }+KM"+@$<  
return sFileName; u;q Q/Ftb  
} B46:LQ9[  
< c^'$  
2.Vrh@FNRo  
public void setSFileName(String value) bPOPoq1#  
{ e#;43=/Ia  
sFileName = value; "rn  
} Z3TC
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{A0F/#M]  
6)^*DJy  
public int getNSplitter() \XB,)XDB  
{ swj\X,{  
return nSplitter; m
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} v"1&xe^4  
9Ad%~qciY  
1!1JT;gG^9  
public void setNSplitter(int nCount) |Gz<I  
{ ([q>.[WbH]  
nSplitter = nCount; V4Rs  
} m-O*t$6  
} j_rO_m<8  
:(~<BiqR(  
nN{DO:_o  
/* RkG?R3e  
**Utility.java \;0pjxq=  
*/ F\JS?zt2  
package NetFox; %DiQTg7V,  
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public class Utility { w@-G_-6W  
@JlT*:Dz  
%h ;oi/pe  
public Utility() uY~mi9E  
{ /9ORVV  
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} 961&rR}d  
zRjbEL  
//线程睡眠 {1)bLG|$  
public static void sleep(int nSecond) 9\!&c<i=  
{ ,.P]5 lE  
try{ ?/&X_O  
Thread.sleep(nSecond); 8 siP  
} [6VM4l"  
catch(Exception e) LE}`rW3  
{ ??nT[bhQ  
e.printStackTrace (); _]*[TGap  
} Mt4]\pMUb  
} HCOsVTl,  
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//日志 .'M.yE~5J  
public static void log(String sMsg) my sXgS&S  
{ BPkMw'a:  
System.err.println(sMsg); Kc]cJ`P4.  
} mdL T7  
? /!Fv/  
dwB#k$VIOw  
public static void log(int sMsg) "#wAGlH6>  
{ +DSbr5"VlB  
System.err.println(sMsg); )q'dX+4=eL  
} wrJQkven-  
} Q3ZGN1aX<  
=Jl\^u%H(x  
[UkcG9  
/* nycJZ}f:wP  
**TestMethod.java jF6Q:`k  
*/ mL1ZSX o!  
package NetFox; 1R-0b{w[  
1W*Qc_5 v1  
]Yt3@ug_f  
public class TestMethod { gs1  
|6-9vU!LK?  
T|\sN*}\8J  
public TestMethod() |u`YT;`!"-  
{ ///xx/weblogic60b2_win.exe MDa[bQNM  
try{ ZOqA8#\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *><j(uz!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '*Y mYU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |8}y?kAC  
fileFetch.start(); BpA7 z/  
} KD#zsL)3  
catch(Exception e){e.printStackTrace ();} Qq{t
X  
w:B&8I(n}w  
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} C,;<SV2#  
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public static void main(String[] args) d.ywH;  
{ @
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new TestMethod(); FBP #_"z  
} r8R7@S2V'  
} Q +hOW-  
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