http断点续传简单实现（java)

/* <p)Z/  
**SiteFileFetch.java QmHwn)Ly  
*/ Oh-Fp-v87  
package NetFox; -s89)lUkS  
import java.io.*; s@z{dmL  
import java.net.*; X/wmKi  
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public class SiteFileFetch extends Thread { } m6\C5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b^%?S8]h  
long[] nStartPos; //开始位置 lc"qqt  
long[] nEndPos; //结束位置 2pjW,I!`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Liij{ahm  
long nFileLength; //文件长度 h
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boolean bFirst = true; //是否第一次取文件 pY,O_ t$  
boolean bStop = false; //停止标志 AX8gij  
File tmpFile; //文件下载的临时信息 {:3.27jQ  
DataOutputStream output; //输出到文件的输出流 KCl &H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jjX'_E  
public SiteFileFetch(SiteInfoBean bean) throws IOException =p5?+3"@  
{ [4ee <J  
siteInfoBean = bean; (lieiye^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6GY32\Ac  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q%DVDq( z  
if(tmpFile.exists ()) z2.*#xTZn  
{ aN:HG)$@  
bFirst = false; <8g=BWA  
read_nPos(); \ibCR~
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} UBL(Nr  
else #>@<n3rq  
{ "$]ls9-%n  
nStartPos = new long[bean.getNSplitter()]; &3WkH W   
nEndPos = new long[bean.getNSplitter()]; DL %S(l  
} v'h3CaA9j  
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} >'eB2  
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public void run() ,tcP=fdk]  
{ k& W
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//获得文件长度 ? 7/W>  
//分割文件 eVZa6la"  
//实例FileSplitterFetch 1NuR/DO  
//启动FileSplitterFetch线程 o<Xc,mP  
//等待子线程返回 hU 9\y  
try{ J 5Wz4`'  
if(bFirst) TNyK@~#m  
{ \m(ymp<c`  
nFileLength = getFileSize(); P{"WlJ  
if(nFileLength == -1) r hiS  
{ 7fap*  
System.err.println("File Length is not known!"); #.<*; rB  
} BPwI8\V  
else if(nFileLength == -2) #L_@s d  
{ 17WNJ  
System.err.println("File is not access!"); a];BW)  
} N8,EI^W8Z  
else 1y},9ym  
{ #S@UTJa  
for(int i=0;i<nStartPos.length;i++) zY]Bu-S3  
{ Z[a
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); &sI,8X2a2  
} U(rr vNt:t  
for(int i=0;i<nEndPos.length-1;i++) @PT`CK}  
{ QN)/,=#  
nEndPos = nStartPos[i+1]; H @_eFlT t  
} 'dmp4VT3  
nEndPos[nEndPos.length-1] = nFileLength; M3DxapG  
} B.]qrS|  
} B`g<Ge~  
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ML=hKwCA  
//启动子线程 e*Uz#w:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P]!LN\[  
for(int i=0;i<nStartPos.length;i++) >{O[t2&  
{ EO4"Z@ji  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =giM@MV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), s5c! ^,L8  
nStartPos,nEndPos,i); xaGVu0q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s(1_:  
fileSplitterFetch.start();
9F2w.(m  
} pieU|?fQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :)KTZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Fy}MXe"f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ov$N"  
nEndPos = " + nFileLength); }4bB7,
j  
// fileSplitterFetch[nPos.length-1].start(); Eg@R[ ^T  
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;whFaQi 4  
//等待子线程结束 OYqYI!N/  
//int count = 0; d8Q_6(Ar|  
//是否结束while循环 hRuo,FS#:  
boolean breakWhile = false; 2x<Qt2"  
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while(!bStop) \3n{w   
{ ()@.;R.Z  
write_nPos(); %{N$1h
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Utility.sleep(500); @e.OU(Bf  
breakWhile = true; BNL8hK`D  
}}sRTW  
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for(int i=0;i<nStartPos.length;i++) rZ8Y=) e  
{ Q.pEUDq/  
if(!fileSplitterFetch.bDownOver) M5cOz|j/*R  
{ [6,]9|~  
breakWhile = false; C>w9 {h  
break; APHtJoS  
} ,E*a$cCw  
} c:?#zX  
if(breakWhile) ecY ^C3+S  
break; h9Tf@]W   
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Q !RVD*(  
//count++; \pewbu5^  
//if(count>4) [}9XHhY1O=  
// siteStop(); K\^&_#MG  
} N#pl mPrZ  
DK@w^ZW6JA  
8}"f|6Wm  
System.err.println("文件下载结束！"); L!8 -:)0b  
} AjL?Qh4  
catch(Exception e){e.printStackTrace ();} 8aZey_Hw;+  
} Ew?/@KAV\  
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//获得文件长度 _pH6uuB  
public long getFileSize() '&pf  
{ !dbA (  
int nFileLength = -1; ~P]HG;$?n  
try{ r.a9W?(E  
URL url = new URL(siteInfoBean.getSSiteURL()); .kB3jfw0,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SVg@xu+  
httpConnection.setRequestProperty("User-Agent","NetFox"); G3_mWppH  
9?}rpA`P  
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int responseCode=httpConnection.getResponseCode(); 5&rCNi*\  
if(responseCode>=400) A=qW]Im  
{ 3Q*RR"3  
processErrorCode(responseCode); +3o)L?:g  
return -2; //-2 represent access is error ?2<6#>(7a  
} $Va]vC8?  
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String sHeader; QnP?;  
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for(int i=1;;i++) p\]LEP\z,  
{ bZOy~F|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bF Y)o Z  
//Utility.log(in.readLine()); rCSG@D.  
sHeader=httpConnection.getHeaderFieldKey(i); l LD)i J1  
if(sHeader!=null) 2W:?#h3  
{ iJaNP%N  
if(sHeader.equals("Content-Length")) ;AL@<,8  
{ _F|_C5A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '3_B1
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break; H'h4@S  
} QWW7I.9r  
} l6DIsR  
else *6x^w%=A  
break; sv{0XVn+^  
} komxot[[  
} f({-j%m  
catch(IOException e){e.printStackTrace ();} GwpBDMk  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); vb ^!(  
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return nFileLength; 10I`AjF0  
} _BLSI8!N@  
`# M.t);^  
' /<b[  
//保存下载信息（文件指针位置） ]-Y]Q%A4  
private void write_nPos() >
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{ *Qwhi&k  
try{ G8DIig<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rKs WS~U  
output.writeInt(nStartPos.length); X-r,>o:  
for(int i=0;i<nStartPos.length;i++) mhkAI@)>  
{ E4aCGg  
// output.writeLong(nPos); lGHu@(n<  
output.writeLong(fileSplitterFetch.nStartPos); /R$x-7t)^(  
output.writeLong(fileSplitterFetch.nEndPos); VJtTbt;>  
} T0"0/{5-_  
output.close(); T&MS_E&;  
} MG5Sn*(C  
catch(IOException e){e.printStackTrace ();} n6UU6t{  
catch(Exception e){e.printStackTrace ();} yr 9)ga%  
} hRZS6" #  
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//读取保存的下载信息（文件指针位置） o^"3C1j  
private void read_nPos() wp GnS  
{ Y~SlipY_  
try{ 3b[+m}UWQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QV7c9)<]'}  
int nCount = input.readInt(); *k]S{]Y  
nStartPos = new long[nCount]; Xg3[v3m|  
nEndPos = new long[nCount]; ~ 2oP,  
for(int i=0;i<nStartPos.length;i++) \bQ
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{ 3udIe$.Q  
nStartPos = input.readLong(); Fsj&/: q  
nEndPos = input.readLong(); ]`H.qV  
} x,G6`|Hl  
input.close(); A.x}%v,E  
} Y"rV[oe  
catch(IOException e){e.printStackTrace ();} FY}*Z=D%  
catch(Exception e){e.printStackTrace ();} LtWU
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} "?&bh@P&  
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private void processErrorCode(int nErrorCode) z\d2T%^:g(  
{ b!~%a  
System.err.println("Error Code : " + nErrorCode); 7kpW1tjY  
} `e|Lw  
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&B0&183  
//停止文件下载 ZDJWd
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public void siteStop() J}KktD@!O  
{ i8@e}O I  
bStop = true; NRF%Qd8I/2  
for(int i=0;i<nStartPos.length;i++) tsVhPo]e0  
fileSplitterFetch.splitterStop(); $uB(@Ft.  
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} nKkTnTSa  
} arL&^]JnZ,  
//负责部分文件的抓取 H).5xx[`  
**FileSplitterFetch.java eaP$/U D?  
*/ lA 0_I"b2Y  
package NetFox; ; 2-kQK9  
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import java.io.*; K -1~K  
import java.net.*; 'X<uG x  
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public class FileSplitterFetch extends Thread { `
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String sURL; //File URL $0 zL  
long nStartPos; //File Snippet Start Position .]c:Zt}P  
long nEndPos; //File Snippet End Position gRI|rDC)B  
int nThreadID; //Thread's ID Bd[Gsns  
boolean bDownOver = false; //Downing is over jhM|gV&  
boolean bStop = false; //Stop identical !iOu07<n&D  
FileAccessI fileAccessI = null; //File Access interface |JQKxvjT  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [_1G\z_iE  
{ `2  
this.sURL = sURL; TY?io@  
this.nStartPos = nStart; imQNfNm  
this.nEndPos = nEnd; tRCd(Z,WY  
nThreadID = id; !W^II>Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E#p6A5  
} N3RwcM9+;  
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public void run() M!'tD!NWc  
{ t$iU|^'uV  
while(nStartPos < nEndPos && !bStop) bNgcZ V.  
{ m#'9)%t!J  
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try{ R8*4E0\br  
URL url = new URL(sURL); XWV~6"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zv@o-R$l  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2Y{9Df  
String sProperty = "bytes="+nStartPos+"-"; "&F/'';0}E  
httpConnection.setRequestProperty("RANGE",sProperty); rD?o97  
Utility.log(sProperty); JJXf%o0yq  
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InputStream input = httpConnection.getInputStream(); 8nM]G4H.f  
//logResponseHead(httpConnection); St<\qC  
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byte[] b = new byte[1024]; >EjBknl  
int nRead; []NAV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) **"sru;@=  
{ T^W8_rm*3  
nStartPos += fileAccessI.write(b,0,nRead); ;H.r6  
//if(nThreadID == 1) ?##GY;#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sob+l'U$  
} .H"gH-I  
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Utility.log("Thread " + nThreadID + " is over!"); fpUX @b  
bDownOver = true; {S c1!2q  
//nPos = fileAccessI.write (b,0,nRead); &Jz%L^  
} )erPp@  
catch(Exception e){e.printStackTrace ();} I|hG"i  
} ^`$KN0PY  
} <JlKtR&nSo  
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//打印回应的头信息 G[<iVt$y  
public void logResponseHead(HttpURLConnection con) &fWZ%C7|jC  
{ {^v50d  
for(int i=1;;i++) ;a|A1DmZ  
{ MLJ8m  
String header=con.getHeaderFieldKey(i); ~$5[#\5%G  
if(header!=null) XyhdsH5%3!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q"\[ICu!,  
Utility.log(header+" : "+con.getHeaderField(header)); N4r`czoj  
else >2$M~to"1  
break; /lUb9&yV  
} sfH|sp  
} (jXgJ" m  
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public void splitterStop() dM)fr  
{ hFKYRZtP.8  
bStop = true; dW91nTQ:  
} A="h}9ok  
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} 9yQ[*  
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/* 4&?%"2  
**FileAccess.java c=7L)w:I  
*//文件访问(定位，写) sI`Lsd'V  
package NetFox; V&gUxS]*  
import java.io.*; _M7AQ5  
pNDL:vMWP  
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public class FileAccessI implements Serializable{ Yu'lD`G  
[ %r :V"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XI pXP,Yy  
RandomAccessFile oSavedFile; w+Ag!O}.L  
long nPos; K2!KMhvQ  
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public FileAccessI() throws IOException C8i}~x<  
{ 9c<lFZb;  
this("",0); bd9]'
  
} WJ=^r@Sf  
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public FileAccessI(String sName,long nPos) throws IOException N[czraFBD}  
{ ze]2-
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oSavedFile = new RandomAccessFile(sName,"rw"); faThXq8B  
this.nPos = nPos; 'Exj|Y&  
oSavedFile.seek(nPos); 9"oc.ue.2D  
} T0
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wR1M_&-s  

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.  
public synchronized int write(byte[] b,int nStart,int nLen) 1)vdM(y3j  
{ uEH&]M>d_  
int n = -1; 8 yQjB-,#  
try{ yX?& K}JI  
oSavedFile.write(b,nStart,nLen); Em-88=XO  
n = nLen; Zn|vT&:Hg  
} [P407Sa"  
catch(IOException e) ggfL d r  
{ $Ic: c  
e.printStackTrace (); IZoa7S&t  
} '*|Wi}0R  
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return n; 5Jlz$]f  
} "8>*O;xk  
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} P'xq+Q  
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/* 7g[T#B'/x,  
**SiteInfoBean.java +h.$<=  
*/ )=8MO-{  
package NetFox; I6ffp!^}Y  
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public class SiteInfoBean { J.N%=-8  
[/.o>R#J(  
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private String sSiteURL; //Site's URL P33x/#VVE  
private String sFilePath; //Saved File's Path 3@f@4t@5V  
private String sFileName; //Saved File's Name UEbRg =6  
private int nSplitter; //Count of Splited Downloading File /:iO:g1  
wM8Gz.9,  
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public SiteInfoBean() fH-V!QY
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{//nSplitter的缺省值为5 5B)Z@-x2  
//default value of nSplitter is 5 icLf;@  
this("","","",5); why;1z>V  
} apPn>\O  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <iDqt5)N  
{ |}P4Gr}6  
sSiteURL= sURL; q^ lx03   
sFilePath = sPath; B/hL  
sFileName = sName; O:3LA-vA  
this.nSplitter = nSpiltter; P]hS0,sE<(  
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} aVcQ  
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public String getSSiteURL() /ZlPEs)  
{ ]N
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return sSiteURL; 9un* 1%  
} 'S]7:/CI  
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public void setSSiteURL(String value) "5Orj*{  
{ ^|-*amh  
sSiteURL = value; RQiGKz5  
} 4Rj;lAlwB  
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public String getSFilePath() ?\[2Po]n  
{ ClZ:#uMbN  
return sFilePath; KZ_d..l*W  
} <,/k"Y=  
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public void setSFilePath(String value) I!'PvIyO  
{ WrWJ!   
sFilePath = value; ~gU.z6us  
} ]r++YIg!j  
/Xa_Xg7  
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public String getSFileName() 6b&<5,=d:  
{ fNjxdG{a  
return sFileName; IO/%X;Y_  
} f`Km ctI  
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public void setSFileName(String value) \Y;LbB8D  
{ "p]bsJG  
sFileName = value; |KSd@  
} o&M2POI~q  
?1%/G<  
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public int getNSplitter() H(f~B<7q  
{ %N}OMc.W  
return nSplitter; =apcMW(zn  
}
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0
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public void setNSplitter(int nCount) |0!oSNJ  
{ 7PE3>cD  
nSplitter = nCount; F3k]*pk8w  
} 'EF\=o)^Y  
} ~~J xw ]  
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/* {O\>"2}m'f  
**Utility.java w[g(8#*  
*/ CE :x;!}cd  
package NetFox; P}=u8(u  
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public class Utility { 5HWVK.  
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public Utility() dQhh,}  
{ 8J60+2Wa  
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} lZyxJDZ A  
iTb k]$  
//线程睡眠 gQ]WNJ~>  
public static void sleep(int nSecond) c;M7[y&  
{ YyI4T/0s_  
try{ 1Ql\aO)  
Thread.sleep(nSecond); kbij Zj{  
} "2cJ'n/L  
catch(Exception e) ?NazfK  
{ 3:q\]]]S  
e.printStackTrace (); -8-BVU  
} FScE3~R  
} \Qa6mt2h  
h/9{E:ML  
//日志 x)'4u6;d  
public static void log(String sMsg) 
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{ 99T_y`df  
System.err.println(sMsg); ;d"F'd  
} .gPE Qc+D  
+-=o16*{ !  
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public static void log(int sMsg) 8FY.u{93  
{ zu6
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System.err.println(sMsg); XY(3!>/eQ[  
} 3q*y~5&I  
} j(j o8  
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vRm.#+Td  
/* UL0%oJ#  
**TestMethod.java
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*/ "tuBfA+f  
package NetFox; 'n>
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public class TestMethod { *Vk%"rwaG  
& i,on6  
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public TestMethod() N 3IF j  
{ ///xx/weblogic60b2_win.exe :Mz$~o<  
try{ "eWN52  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <{rRcFR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lWj|7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !;'.mMO&%  
fileFetch.start(); =$`xis\  
} Vl;GQe  
catch(Exception e){e.printStackTrace ();} as\6XW$;Q  
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} J[9yQ  
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public static void main(String[] args) oY@4G)5  
{ %1Gat6V<'  
new TestMethod(); b-e3i;T!}~  
} ,: X+NQ  
} /H+br_D9  
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