http断点续传简单实现（java)

/* $i] M6<Vxn  
**SiteFileFetch.java JNg5?V;.U  
*/ 3Qr!?=nf  
package NetFox; &rWJg6/  
import java.io.*; EUS]Se2  
import java.net.*; Y9ce"*b  
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public class SiteFileFetch extends Thread { E1v<-UPbA  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3VBV_/i;  
long[] nStartPos; //开始位置 H#`?toS  
long[] nEndPos; //结束位置 htSk2N/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #_|^C(]!  
long nFileLength; //文件长度 k<hO9;#qpL  
boolean bFirst = true; //是否第一次取文件 I~6 ;9TlQ  
boolean bStop = false; //停止标志 6oBt<r?CJ  
File tmpFile; //文件下载的临时信息 <aD+Ki6  
DataOutputStream output; //输出到文件的输出流 `7n,(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `8bp6}OD,  
public SiteFileFetch(SiteInfoBean bean) throws IOException xEWa<P#.u  
{ CfnCi_=[`  
siteInfoBean = bean; ne*aC_)bT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sb5kexGxkc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PS]XLz  
if(tmpFile.exists ()) X0=-{<W  
{ 3yX^R^`  
bFirst = false; <Y
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read_nPos(); \Rt  
} 7NqV*  
else tqf-,BLh  
{ =#fvdj  
nStartPos = new long[bean.getNSplitter()]; tR/ J
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nEndPos = new long[bean.getNSplitter()]; TI&J>/z;$  
} e%>E| 9*u  
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} U]3JCZ{]0E  
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public void run() NtL?cWct  
{ emO!6]0gJ  
//获得文件长度 H9[.#+ln  
//分割文件 50`r}
s}  
//实例FileSplitterFetch cIkLdh   
//启动FileSplitterFetch线程 \bE~iz3b9  
//等待子线程返回 svgi!=  
try{ a]ey..m  
if(bFirst) T^>cT"ux_  
{ jGPs!64f)  
nFileLength = getFileSize(); nTlrG6  
if(nFileLength == -1) KWMH|sxO=  
{ A 76yz`D  
System.err.println("File Length is not known!"); 014!~c  
} [%q":I
g  
else if(nFileLength == -2) (U<wKk"  
{ z05pVe/5  
System.err.println("File is not access!"); dGN*K}5  
} "0mR*{nF  
else c+VUk*c3  
{ Jt][b  
for(int i=0;i<nStartPos.length;i++) H^0KNMf(  
{ p]HtJt|]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7n.J.<+9  
} JH9CN  
for(int i=0;i<nEndPos.length-1;i++) )63w&  
{ m0YDO0  
nEndPos = nStartPos[i+1]; sS|5x  
} 2x CGr>X  
nEndPos[nEndPos.length-1] = nFileLength; SOJHw6  
} Pr'py  
} 35et+9  
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//启动子线程 0KEl+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fN;
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for(int i=0;i<nStartPos.length;i++)
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{ \!Pm^FD .  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yR-.OF,c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T8k oP  
nStartPos,nEndPos,i); &[xJfL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  VPzdT*g]  
fileSplitterFetch.start(); Zs)9OJu  
} +q!6zGs.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ft7l/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DoA f,9|_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *{Vyt5  
nEndPos = " + nFileLength); Hr'#
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// fileSplitterFetch[nPos.length-1].start(); x8t1g,QA  
iFnM6O$(  
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//等待子线程结束 NaIVKo  
//int count = 0; .7q#{`K^=  
//是否结束while循环 >"b"
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boolean breakWhile = false; mJHX  
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7}MWmS^8j  
while(!bStop) F);C?SW"  
{  E2l.  
write_nPos(); BL7%MvDQ  
Utility.sleep(500); ]T1"3 [si  
breakWhile = true; mvnK)R_  
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for(int i=0;i<nStartPos.length;i++) 2]l*{l^ Bl  
{ V=U%P[S  
if(!fileSplitterFetch.bDownOver) !&kOqc5:t<  
{ >ObpOFb%  
breakWhile = false; S<44{ oH  
break; x<"e  
} gNJ\*]SY  
} $kdfY'u  
if(breakWhile) +!rK4[W'  
break; Nz8iU@!a  
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=0A{z#6  
//count++; 8EQ;+V  
//if(count>4) |2Dlw]d  
// siteStop(); mdwY48b  
} +KZc"0?
 
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System.err.println("文件下载结束！"); -kkXyO8js  
} ZD*>i=S  
catch(Exception e){e.printStackTrace ();} g`6S*&8I  
} K%;O$ >  
!zeBxR$&o  
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//获得文件长度 IkupW|}rc  
public long getFileSize() V6c?aZ,O  
{ 8w$cj'  
int nFileLength = -1; z&eJ?wb  
try{ PO#FtG  
URL url = new URL(siteInfoBean.getSSiteURL()); FU<rE&X2:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }k%>%xQ.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5<61NnZ  
_=
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int responseCode=httpConnection.getResponseCode(); {)G3*>sG3  
if(responseCode>=400) 9P]TIV.  
{ .Xr_BJ _  
processErrorCode(responseCode); ;^;5"nh  
return -2; //-2 represent access is error SL(Q;_  
} |KA8qQI]
%  
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String sHeader; R1U\/  
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for(int i=1;;i++) bF3j*bpO"  
{ uzsR*x%s-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 79&Mc,69  
//Utility.log(in.readLine()); YO=;)RA  
sHeader=httpConnection.getHeaderFieldKey(i); KxvT}"k  
if(sHeader!=null) +_+_`q>]  
{ ym:JtI69   
if(sHeader.equals("Content-Length")) 9F3`hJZRy>  
{ r`lgK2r\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zX3O_  
break; 8ciLzyrY*  
} UZV)A}  
} "?]5"lNC|  
else E3`KO'v%  
break; |^FDsJUN  
} 1Eg,iTn2*x  
} yfV{2[8ux  
catch(IOException e){e.printStackTrace ();} @NO&3m]  
catch(Exception e){e.printStackTrace ();} "5{\0CfS  
4((Z8@iX/  
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Utility.log(nFileLength); BWd?a6nU}  
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return nFileLength; a"~W1|JC"  
} rq$%  
$UKDXQF"  
e&E*$G@.7  
//保存下载信息（文件指针位置） qWo|LpxWt  
private void write_nPos() DD;PmIW  
{ "|f;   
try{ m|p}Jf!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }V`Fz',lZ  
output.writeInt(nStartPos.length); T%Z`:mf  
for(int i=0;i<nStartPos.length;i++) jAF DkqH  
{ 3n X7$$X  
// output.writeLong(nPos); ctj.rC)6n  
output.writeLong(fileSplitterFetch.nStartPos); j+s8V-7(  
output.writeLong(fileSplitterFetch.nEndPos); i3YAK$w;&  
} aX0sy\Z]j  
output.close(); X!r!lW  
} enZW2o97c  
catch(IOException e){e.printStackTrace ();} ${`\In_?O  
catch(Exception e){e.printStackTrace ();} `,TPd ~#~  
} 0ro)e~_@*  
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//读取保存的下载信息（文件指针位置） Il!iqDHz3  
private void read_nPos() Dz.U&+*  
{ Rb#?c+&
#  
try{ x!S8'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 10*U2FY)]  
int nCount = input.readInt(); nQ8EV>j2  
nStartPos = new long[nCount]; =_=jXWOQv  
nEndPos = new long[nCount]; )5&Wt@7Kj`  
for(int i=0;i<nStartPos.length;i++) i;yz%Ug  
{ -^C;WFh8)  
nStartPos = input.readLong(); )00#Rrt9  
nEndPos = input.readLong(); (/PD;R$b  
} |IZG`
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input.close(); *,mbZE=<  
} u{8Wu;  
catch(IOException e){e.printStackTrace ();} b@nbXm]Z  
catch(Exception e){e.printStackTrace ();} ;\(wJ{u?Y  
} H#G'q_uHH  
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private void processErrorCode(int nErrorCode) dAohj QH:  
{ B3e{'14  
System.err.println("Error Code : " + nErrorCode); ?5"~V^L3  
} m`E8gVC  
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//停止文件下载 "?n~ /9`  
public void siteStop() B4_0+K H  
{ &`0heJ 5Yn  
bStop = true; (
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for(int i=0;i<nStartPos.length;i++) :1=
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fileSplitterFetch.splitterStop(); <wc=SMmO  
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} zr2%|YF  
} T'0Ot
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//负责部分文件的抓取 IgQW 5E#  
**FileSplitterFetch.java jW"C: {Ol;  
*/ hyVuZ\9B  
package NetFox; #*1\h=bzmW  
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import java.io.*; 9^3y\@ m  
import java.net.*; Ri"3o  
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public class FileSplitterFetch extends Thread { VLkK6W.u  
;HgV(d#X  
(]0ZxWF  
String sURL; //File URL aB#qzrr['8  
long nStartPos; //File Snippet Start Position (KK9/k  
long nEndPos; //File Snippet End Position #=q)>+\  
int nThreadID; //Thread's ID uJ{N?  
boolean bDownOver = false; //Downing is over hd8:|_  
boolean bStop = false; //Stop identical ccZ A  
FileAccessI fileAccessI = null; //File Access interface 8 U B?X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w f,7  
{ y8D'V)B
  
this.sURL = sURL; w`UB_h#Bl  
this.nStartPos = nStart; yo#&>W  
this.nEndPos = nEnd; /~K-0K#w  
nThreadID = id; o
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Yvcd(2  
} ry/AF  
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public void run() .u>IjK^  
{ 3BDAvdJ4.  
while(nStartPos < nEndPos && !bStop) @K7#}7,t  
{ YrS%Yvhj0  
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try{ O\,n;oj  
URL url = new URL(sURL); X@*$3z#Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +FP*RNM  
httpConnection.setRequestProperty("User-Agent","NetFox"); cP''  
String sProperty = "bytes="+nStartPos+"-"; c6:"5};_  
httpConnection.setRequestProperty("RANGE",sProperty); ?H#]+SpOcv  
Utility.log(sProperty); *Sm$FMWQ  
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InputStream input = httpConnection.getInputStream(); G,FYj'<!7,  
//logResponseHead(httpConnection); s/ibj@h  
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byte[] b = new byte[1024]; }xJ9EE*G/  
int nRead; ,[71,zs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )2C_6eR  
{ N 3i,_  
nStartPos += fileAccessI.write(b,0,nRead); RMMx6L|-:  
//if(nThreadID == 1) a;|C51GH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jhr{JApbJv  
} *-(J$4RNz  
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Utility.log("Thread " + nThreadID + " is over!"); qba<$  
bDownOver = true; QKDY:1]  
//nPos = fileAccessI.write (b,0,nRead); 6q RZ#MC  
} wXIsc;  
catch(Exception e){e.printStackTrace ();} !([Q1r{u  
} ?dP3tLR  
} 3P-qLbJ  
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/-Y*V*E  
//打印回应的头信息 b*S:wfw  
public void logResponseHead(HttpURLConnection con) POwJhT  
{ <*E{zr&  
for(int i=1;;i++) <"Z]S^>$  
{ cobq+Iyu  
String header=con.getHeaderFieldKey(i); 2siUpmX  
if(header!=null) $p30?\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xWWfts1t  
Utility.log(header+" : "+con.getHeaderField(header)); |q"WJQ  
else .<}(J#vC  
break; +QT(~<  
} w-*$gk]  
} {|= 8wB  
u P
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public void splitterStop()
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{ jE|Ju:}&  
bStop = true; r\Nf309~  
} rK)aR  
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} iD+Q\l;%  
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/* 8gwJ%"-K  
**FileAccess.java ;S5*n:d  
*//文件访问(定位，写) N+%E=D>  
package NetFox; #D~atgR
 
import java.io.*; U?97yc\$  
3qU#Rg ;7  
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public class FileAccessI implements Serializable{ S'm&Ll2
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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 Y^$^B,  
RandomAccessFile oSavedFile; 9,wd,,ta  
long nPos; u&Ts'j  
b-R!oP+vP  
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public FileAccessI() throws IOException Lsa&A+fru  
{ ka? |_(  
this("",0); 2Pn  
}  *X- 6]C  
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public FileAccessI(String sName,long nPos) throws IOException Q`k=VSUk  
{ lj0"2@z3"E  
oSavedFile = new RandomAccessFile(sName,"rw"); o&}!bq]  
this.nPos = nPos; `(s&H8x#  
oSavedFile.seek(nPos); Y^DS~CrM  
} epM;u  
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public synchronized int write(byte[] b,int nStart,int nLen) .w=(
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{ :ad  
int n = -1; H0<(j(JK  
try{ <>JN&#3?  
oSavedFile.write(b,nStart,nLen); 1xN6V-qk  
n = nLen; X+zFRL%  
} 8q9HQ4dsL  
catch(IOException e) &|>CW:)&1"  
{ 0G`_dMN  
e.printStackTrace (); Sc03vfmo"N  
} *ue- x!"c  
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return n; GPBp.$q+B  
} 1OB,UU"S$  
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} gB/4ro8  
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/* 7<{g+Q~7*  
**SiteInfoBean.java ~ [L4,q  
*/ }uWIF|h~  
package NetFox; `K -j  
~2 L{m[s|  
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public class SiteInfoBean { 8m%+O#  
X(sHFVU+  
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private String sSiteURL; //Site's URL B*
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private String sFilePath; //Saved File's Path W/03L, 1  
private String sFileName; //Saved File's Name ?,GCR1|4  
private int nSplitter; //Count of Splited Downloading File &o{=  
*sNZ.Y:.  
#E35%7*  
public SiteInfoBean() +ob<?  T  
{//nSplitter的缺省值为5 Uc oVp}vl  
//default value of nSplitter is 5 dkT
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this("","","",5); `PML4P[  
} 0\fV'JDOR  
n~~0iU)  
+; /]'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2.''Nt6|  
{ L~x PIu  
sSiteURL= sURL; XLwmXi  
sFilePath = sPath; 2R}9wDP  
sFileName = sName; 3FWl_d~uD  
this.nSplitter = nSpiltter; {NmpTb  
]/byz_7]  
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} yb 7  
)ro3yq4??  
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public String getSSiteURL() )=,%iL-  
{ ]IX6>p,  
return sSiteURL; j_=A)B?  
} 6yDc4AX  
+{b!,D3sa*  
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public void setSSiteURL(String value) g&z)y  
{ SZ/}2_;  
sSiteURL = value; $bf&ct*$h  
} =+I~K'2  
<d2?A}<  
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public String getSFilePath() !m7`E  
{ PvmmyF  
return sFilePath; b=V"$(Q  
} I``S%`h  
+ZuT\P&kR5  
h6Femis  
public void setSFilePath(String value) ^]x%z*6  
{ M84{u!>[  
sFilePath = value; r>!$eqX_  
} j41)X'MgJ  
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public String getSFileName() X#625h  
{ C*+gQeK  
return sFileName; ny(`An  
} z
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public void setSFileName(String value) pQQN8Y~^Y  
{ *=sMJY9#jE  
sFileName = value; *wH.]$  
} K-_XdJ\  
{6_M$"e.  
*En29N#a{  
public int getNSplitter() 2)iwAu   
{ :i{Svb*_'  
return nSplitter; [`F}<L."  
} .Y
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public void setNSplitter(int nCount) )bd)noZi  
{ aUy!(Y  
nSplitter = nCount; )S:,q3gxJ  
} 0XcH  
} 9\QeH'A  
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/* -qbx:Kk(  
**Utility.java C`J>Gm  
*/ m{ wk0  
package NetFox; s6DmZ^Y%  
9wTN*y  
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public class Utility { .83{NF  
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3}7`?$5  
public Utility() Daw;6f:  
{ &H4Y`xV^=  
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/e:kBjysJ  
} @TQzF-%#7  
} SNZl`>  
//线程睡眠 '^{:HR#i  
public static void sleep(int nSecond) aPwUC:>`D  
{ /<R[X>]<F  
try{ .c5)`  
Thread.sleep(nSecond); JK/gq}c  
} {!L25  
catch(Exception e) 0Ym_l?]m[  
{ {f(RYj  
e.printStackTrace (); m|M'vzu1  
} 61@;3yV  
} S;8gX1Uf  
3J_BuMV  
//日志 )Jaq5OMA/  
public static void log(String sMsg) mm:g9j  
{ ubQbEv{(,  
System.err.println(sMsg); [S_qi,  
} qRcY(mb  
'@{Mq%`  
?r'2GR2Sk4  
public static void log(int sMsg) u85dG7  
{ h]jy):9L  
System.err.println(sMsg); Bln($lOz  
} EY^+ N>  
} :pCv!g2  
'JRYf;9c  
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/* )>]@@Trx  
**TestMethod.java p9-s'F|@i  
*/ "qdEu KI  
package NetFox; ~wFiq)v(  
aCF=Og  
l2ARM3"  
public class TestMethod { :[J'B4>9  
He)!Ez\X  
mX
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public TestMethod() E0)43  
{ ///xx/weblogic60b2_win.exe [J8;V|v  
try{ XI\P#"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X.GK5Phd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E<[Y KY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e X{#FgFc  
fileFetch.start(); <lgX=wx L  
} ;J,`v5z0:  
catch(Exception e){e.printStackTrace ();} eL_Il.:  
w2) @o>w  
m0p%R>:5  
} yHf:/8Z  
wE3fKG.  
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public static void main(String[] args) lSG]{  
{ 1\Z/}FT  
new TestMethod(); _P9*78  
} i:|e#$x  
} b

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