http断点续传简单实现（java)

/* wM-H5\9n  
**SiteFileFetch.java p=i6~   
*/ 8A-*MU`+  
package NetFox; 9.#")%_p  
import java.io.*; J^PFhu  
import java.net.*;  R;&k/v  
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public class SiteFileFetch extends Thread { [;:ocy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^![7X'!;pt  
long[] nStartPos; //开始位置 i!(5y>I_  
long[] nEndPos; //结束位置 x~D8XN{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2<'ol65/c  
long nFileLength; //文件长度 WVp6/HS  
boolean bFirst = true; //是否第一次取文件 :RBeq,QaO  
boolean bStop = false; //停止标志  >Af0S;S  
File tmpFile; //文件下载的临时信息 Z;0<k;#T(p  
DataOutputStream output; //输出到文件的输出流 t9lf=+%s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qn}VW0!  
public SiteFileFetch(SiteInfoBean bean) throws IOException iVmy|ewd  
{ 8R(l~  
siteInfoBean = bean; hwi_=-SL  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); pm[i#V<v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 66_=bd(9  
if(tmpFile.exists ()) |X6R2
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{ Rz*GRe
 
bFirst = false; <KoOJMx(  
read_nPos(); [W3sveqj&  
} e$rPXRf  
else T+%P+  
{ A#i[Us|  
nStartPos = new long[bean.getNSplitter()]; #2Iw%H2q&  
nEndPos = new long[bean.getNSplitter()]; yi(IIW  
} EEx:Xk%5hX  
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} g-m,n=qu  
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public void run() 3m$Qd#|  
{ VT#`l0I}  
//获得文件长度 taO(\FOm  
//分割文件 >S{8sN
 
//实例FileSplitterFetch NJQy*~P  
//启动FileSplitterFetch线程 2zX9c<S=5  
//等待子线程返回 =&FaMR2  
try{ 5EECr \*  
if(bFirst) P{StF`>Y  
{ w:R#F( 'B  
nFileLength = getFileSize(); N!-P2)@  
if(nFileLength == -1) :6o|6MC!  
{ 7$IR^  
System.err.println("File Length is not known!"); zzd PR}VG  
} ^E+fmY2a  
else if(nFileLength == -2) Qj|tD+<  
{ <;1M!.)5  
System.err.println("File is not access!"); {qCFd  
} 3Jj&wHp]  
else .>1Y-NM  
{ q[+KQ,  
for(int i=0;i<nStartPos.length;i++) .5 {<bY  
{ sx'eu;S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (/{bJt~b  
} PZ?kv4  
for(int i=0;i<nEndPos.length-1;i++) k6RH]Ha  
{ Tv~Ho&LS  
nEndPos = nStartPos[i+1]; ^D ;EbR  
} 9}a&:QTHR  
nEndPos[nEndPos.length-1] = nFileLength; M+lr [,c  
} K7i@7  
} 2dbn~j0  
J L1]auO*  
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//启动子线程 k
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 79h'sp6;  
for(int i=0;i<nStartPos.length;i++) [N"=rY4G  
{ la^K|!|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mDuS-2G=D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LE?sAN  
nStartPos,nEndPos,i); [b~+VeP+p4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7[0CVWs,  
fileSplitterFetch.start(); vRDs~'f  
} \#F>R,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J?hs\nA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,F "P/`i'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]AN%#1++U  
nEndPos = " + nFileLength); X[SIk%{D  
// fileSplitterFetch[nPos.length-1].start(); d-8{}Q  
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//等待子线程结束 (io[O?te  
//int count = 0; 4C*0MV  
//是否结束while循环 ,zZ@QW5  
boolean breakWhile = false; ^a1k"|E?f  
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while(!bStop) :dxKcg7  
{ 8;,|z%rS"  
write_nPos(); )XoMOz  
Utility.sleep(500); k3
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breakWhile = true; *V[I&dKq  
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~  
for(int i=0;i<nStartPos.length;i++) DV)NY!  
{ 8~BLTZ  
if(!fileSplitterFetch.bDownOver) oE0~F|(\1  
{ i8f+woZL  
breakWhile = false; bh3yH>Zns  
break; wT-Kg=-q  
} 5s>>] .%  
} B^{~,'  
if(breakWhile) ~c*kS E2X  
break; T#vY(d  
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//count++; u}rJqZ  
//if(count>4) S9
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// siteStop(); ;3%Y@FS@  
} UVW4KUxR  
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System.err.println("文件下载结束！"); sI{?4k  
} :%+9y @%  
catch(Exception e){e.printStackTrace ();} V=YDqof  
} $)KNpdXh  
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rMw$T=Oi  
//获得文件长度 QB;TQZ  
public long getFileSize() yf4 i!~  
{ ~3%aEj  
int nFileLength = -1; Y3-f68*(  
try{ xZ SDA8kS  
URL url = new URL(siteInfoBean.getSSiteURL()); ]Z52L`k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S@TfZ3Go|  
httpConnection.setRequestProperty("User-Agent","NetFox"); &MB1'~Q,hq  
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int responseCode=httpConnection.getResponseCode(); I$XwM  
if(responseCode>=400) Tl+PRR6D*
 
{ `P$X`;SwE  
processErrorCode(responseCode); 2+*o^`%4P
 
return -2; //-2 represent access is error 05 .EI)7  
} lwjA07i  
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String sHeader; i<q_d7-W'  
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for(int i=1;;i++) kUr/*an  
{ 6]4=8! J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8m#y>`  
//Utility.log(in.readLine()); $I<\Yuy-M9  
sHeader=httpConnection.getHeaderFieldKey(i); %_~1(Glz  
if(sHeader!=null) {!!8 *ix  
{ (`R heEg@f  
if(sHeader.equals("Content-Length")) _x$\E  
{ }FX:sa?5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fUOQ(BGp  
break; m/< @Qw  
}  lsgZ  
} K@{R?j/+  
else xqauSW  
break; (UTA3Db  
} WmRu3O  
}  @l&{ j  
catch(IOException e){e.printStackTrace ();} #vAqqAS`,  
catch(Exception e){e.printStackTrace ();} V?-2FK]  
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Utility.log(nFileLength);
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def\=WyK  
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return nFileLength; Digx#'#jf  
} %/SHB  
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p4$4;)  
//保存下载信息（文件指针位置） `7.$ A U  
private void write_nPos() ij.NSyk9  
{ Z2-"NB  
try{ aY DM)b}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =4OV }z=I  
output.writeInt(nStartPos.length); }C$D-fH8sW  
for(int i=0;i<nStartPos.length;i++) nj-LG!"a  
{ 1KjzKFnb  
// output.writeLong(nPos); 6=*n$l#}  
output.writeLong(fileSplitterFetch.nStartPos); eQMa9_  
output.writeLong(fileSplitterFetch.nEndPos); R~;8v1>K  
} 7&(h_}Z  
output.close(); tqL2' (=  
} ,pUB[w\  
catch(IOException e){e.printStackTrace ();} }*vE/W  
catch(Exception e){e.printStackTrace ();} +,)Iv_Xl$  
} JZJb&q){  
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};f^*KZ=0  
//读取保存的下载信息（文件指针位置） Kp!A ay  
private void read_nPos() ]H<}6}
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{ V|/N-3M  
try{ ?.c:k;j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6w_TL<S  
int nCount = input.readInt(); |;"(C# B  
nStartPos = new long[nCount]; ?uW} XAi  
nEndPos = new long[nCount]; Cn_r?1{W  
for(int i=0;i<nStartPos.length;i++) Oe;1f#`5  
{ Fz5eCe\B  
nStartPos = input.readLong(); Ci2*5n<  
nEndPos = input.readLong(); lbh7`xCR  
} <<-BQ l~  
input.close(); (%9J(4  
} zKh<zj  
catch(IOException e){e.printStackTrace ();} ucJ8l(?Qc  
catch(Exception e){e.printStackTrace ();}
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} hI*6f3Vn(n  
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private void processErrorCode(int nErrorCode) TxTxyYd  
{ +6L.a3&(b  
System.err.println("Error Code : " + nErrorCode); cs4IO O$  
} }
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vorb?iVf>  
_*xY>?Aq  
//停止文件下载 y`cL3 xr4R  
public void siteStop() VmZDU(M  
{ Gq7\b({=  
bStop = true; mt[ #=Yba  
for(int i=0;i<nStartPos.length;i++) *g4Uo{  
fileSplitterFetch.splitterStop(); !
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} om6`>I*  
} 3w/z$bj  
//负责部分文件的抓取 b$tf9$f  
**FileSplitterFetch.java GKG:iR)  
*/ zXxA"  
package NetFox; Ym$`EN  
"S>VqvH3  

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import java.io.*; [I[*?9}$"  
import java.net.*; Zj0h0Vt  
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public class FileSplitterFetch extends Thread { ('.I)n  
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String sURL; //File URL E_{P^7Z|Jg  
long nStartPos; //File Snippet Start Position g O8~$Aj  
long nEndPos; //File Snippet End Position N1U.1~U  
int nThreadID; //Thread's ID ciW;sK8  
boolean bDownOver = false; //Downing is over d-gcXaA-8  
boolean bStop = false; //Stop identical ^GiWU +`  
FileAccessI fileAccessI = null; //File Access interface 'G`xD3 E3,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x$pz(Q&v  
{ _6]tbni?v  
this.sURL = sURL; bvT$/(7  
this.nStartPos = nStart; `u8(qGg7GF  
this.nEndPos = nEnd; r'@7aT&_  
nThreadID = id; f+Fzpd?wS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d~T@fa  
} <<9|*Tz  
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public void run() WWLf'89It  
{ ;h#Q!M&e#  
while(nStartPos < nEndPos && !bStop) vJ;0%;eu[!  
{ %mOQIXr1s  
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try{ TnuA uui*  
URL url = new URL(sURL); EV;"]lC9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {9~3y2:  
httpConnection.setRequestProperty("User-Agent","NetFox"); j ~I_by  
String sProperty = "bytes="+nStartPos+"-"; uTy00`1  
httpConnection.setRequestProperty("RANGE",sProperty); F#RtU :R  
Utility.log(sProperty); qporH]J-E  
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InputStream input = httpConnection.getInputStream(); dX-j3lM:#  
//logResponseHead(httpConnection); FQ/z,it_i  
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byte[] b = new byte[1024]; +}BKDEb  
int nRead; ~Yre(8+M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \3x+Z!  
{ cxIAI=JK  
nStartPos += fileAccessI.write(b,0,nRead); $6d5W=u$H  
//if(nThreadID == 1) K)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .AF\[IQ  
} U:|:Y=O?Q  
( ;KTV*1  
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Utility.log("Thread " + nThreadID + " is over!"); QO4eDSW  
bDownOver = true; 04a@  
//nPos = fileAccessI.write (b,0,nRead); 0Q]{r )  
} 'Xasd3*Py  
catch(Exception e){e.printStackTrace ();} T|5uywA|  
} O44Fj)  
} hKems3  
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//打印回应的头信息 -r[O_[g w  
public void logResponseHead(HttpURLConnection con) :GM3n$  
{ `
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for(int i=1;;i++) Lv#}Gm  
{ (Y"./BDY  
String header=con.getHeaderFieldKey(i); p<B*)1Tj0  
if(header!=null) D% 2S!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B!J&=*=e  
Utility.log(header+" : "+con.getHeaderField(header)); _V3}F1?W  
else [6nN]U~Y  
break; 6)~7Uf:<v  
} Zy>y7O(,  
} M2A_T.F=H  
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public void splitterStop() WKq{g+a  
{ i,l$1g-i  
bStop = true; Z{_YH7_  
} (?P\;yDG  
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} jori,"s  

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/* O/oLQoH  
**FileAccess.java 161IWos  
*//文件访问(定位，写) |
  
package NetFox; Q%0 N\  
import java.io.*; \CYKj_c  
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public class FileAccessI implements Serializable{ |sAl k,8s  
!@FzP@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QPB^%8  
RandomAccessFile oSavedFile; V:lKF')  
long nPos; 3.Jk-:u %m  
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X//=OpS`  
public FileAccessI() throws IOException yY"n:&T(  
{ 4^ZbT  
this("",0); +_
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} Ag;Ybk[  
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public FileAccessI(String sName,long nPos) throws IOException 12}!oS~_  
{ j!IkU}*c  
oSavedFile = new RandomAccessFile(sName,"rw"); &HqBlRo  
this.nPos = nPos; f
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oSavedFile.seek(nPos); z:A_  
} :VX2&*  
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public synchronized int write(byte[] b,int nStart,int nLen) nlc$"(eA[H  
{ ^a7a_M  
int n = -1; kXOc)  
try{ 5GURfG3{  
oSavedFile.write(b,nStart,nLen);
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n = nLen;
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} -.5R.~@  
catch(IOException e) k:z)Sw  
{ $,nidK!"  
e.printStackTrace (); zw0u|q;#  
} Y,-!QFS#  
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return n; Y"TrF(C  
} P6`LUyz3  
}|],UXk{xB  
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} )eH?3""  
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/* 3.h0  
**SiteInfoBean.java (bD#PQXzm  
*/ ?BU?c:"f  
package NetFox; oKPG0iM:  
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&pHXSU  
public class SiteInfoBean { 6|1*gl1_LD  
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private String sSiteURL; //Site's URL H?;@r1ZAn  
private String sFilePath; //Saved File's Path u0%bv\$m  
private String sFileName; //Saved File's Name Wp^A.  
private int nSplitter; //Count of Splited Downloading File af&P;#U  
v|nt(-JX  
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public SiteInfoBean() LKg9{0Y:  
{//nSplitter的缺省值为5 U[hokwZ  
//default value of nSplitter is 5 k|cP]p4,  
this("","","",5); ;b
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} 5YXMnYt9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {]O.?Yru?  
{ U/-|hfh  
sSiteURL= sURL; dlwOmO'Bm)  
sFilePath = sPath; :DFtH13qO  
sFileName = sName; SOluTFxUw  
this.nSplitter = nSpiltter; vtRz;~,Z  
HC| ]Au  
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} e]V7 7oc  
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public String getSSiteURL() 5IbCE.>iU  
{ wif1|!aL  
return sSiteURL; <WL] (-9I:  
} ?8q4texf[  
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public void setSSiteURL(String value) w=thaF.  
{ s^/2sjoL  
sSiteURL = value; 5oo6d4[  
} nQG<OVRClS  
yjM!M|  
8L*#zaSAf  
public String getSFilePath() f+2mX"Z[F  
{ DK|/|C}6  
return sFilePath; G#6O'G N  
} Z
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public void setSFilePath(String value) 0bjZwC4J  
{ v1 f^gde  
sFilePath = value; b2~5LZ  
} 7/dp_I}cO  
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public String getSFileName() . Fm| $x  
{ q0@b d2}  
return sFileName; \psO$TxF=  
} fF.+{-.  
+B4i,]lCx  
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public void setSFileName(String value) \M~uNWv|  
{ B XO,  
sFileName = value; 9/O\769"'  
} m [BV{25  
\mw5 ~Rf;  
>d
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public int getNSplitter() Hh%|}*f_,  
{ |Rb8/WX  
return nSplitter; #2%8@?_-M  
} /L` +  
?Xqkf>  
QV _aM2  
public void setNSplitter(int nCount) _w7yfZLv+  
{ h-\+# .YP  
nSplitter = nCount; *?o 'sTH  
} %%lJyLq'Vk  
} 9dp1NjOtAc  
#YSFiy:+r_  
}jYVB|2  
/* isz-MP$:K5  
**Utility.java {-yw@Kq  
*/ YyC$\HH6  
package NetFox; >FL%H=]  
ty8E;['  
"4.A@XsY  
public class Utility { ![m6$G{y  
ilQt`-O!  
//yz$d>JN  
public Utility() COA>y?  
{ 8/-hODoT_  
>&Vz/0  
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} _]us1  
(_fovV=  
//线程睡眠 aQ0pYk~(  
public static void sleep(int nSecond) ?qb
q\t  
{ ,6x>gcR  
try{ RF'&.RtVa  
Thread.sleep(nSecond); ~P"o
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} A#]78lR  
catch(Exception e) Xkf|^-n  
{ [vxHsY3z  
e.printStackTrace (); ubl)$jZ:Q  
} P-X2A2  
} ^NO4T  
2W;2._  
//日志 c=p!2jJ1K~  
public static void log(String sMsg) Kae-Y  
{ \ F)}brPc  
System.err.println(sMsg); P3TM5  
} TmJXkR.5  
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public static void log(int sMsg) ZN!<!"~  
{ {
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System.err.println(sMsg); 3lN@1jlh  
} l_P90zm39!  
} U"L-1]L  
BxB B](  
zEw~t&:e  
/* Sp[]vm8N  
**TestMethod.java Cw~fP[5XMF  
*/ t_\&LMD  
package NetFox; H"wIa8A  
 Rp6q)  
=|H.r9-PK6  
public class TestMethod { }w{E<C(M  
x}#N?d
  
2g;Id.i>  
public TestMethod() i>(TPj|  
{ ///xx/weblogic60b2_win.exe G}@a]EGm  
try{ )g`~,3G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uz;eYD
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l6.&<0pLT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?3<Y/Vg%c  
fileFetch.start(); Fp>nu_-"  
} LXf|n  
catch(Exception e){e.printStackTrace ();} 40 zO4  
mcxD#+H 3  

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} \9]-(j6[H  
imyfki $B  
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public static void main(String[] args) >".@;  
{ -cP1,>Ahv  
new TestMethod(); 0+AMN-  
} pMoza8  
} ;&MnPFmq  
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