http断点续传简单实现（java)

/* 1F
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**SiteFileFetch.java czRFMYE  
*/ W+ko
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package NetFox; Y^EcQzLw  
import java.io.*; dvJM6W>^=  
import java.net.*; >_"an~Ss  
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public class SiteFileFetch extends Thread { D!-g&HBTC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean T!WT;A  
long[] nStartPos; //开始位置 )"aV* "  
long[] nEndPos; //结束位置 PKg@[<g43  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *]/zc1Q4M  
long nFileLength; //文件长度 '^~{@~ ;%L  
boolean bFirst = true; //是否第一次取文件 A!WKnb_`  
boolean bStop = false; //停止标志 4-H+vNG{%  
File tmpFile; //文件下载的临时信息 "8jf81V*  
DataOutputStream output; //输出到文件的输出流 U7}yi$WT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qL3;}R  
public SiteFileFetch(SiteInfoBean bean) throws IOException {dMsz   
{ ]tRu2Ygf  
siteInfoBean = bean; dufu|BL|}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ata:^q
I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UJ7*j%XQz_  
if(tmpFile.exists ()) %oa-WmWm  
{ 3>`mI8$t  
bFirst = false; }"%?et(  
read_nPos(); EGU 0)<  
} X296tA>C`  
else 9BBmw(M}  
{ kr
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nStartPos = new long[bean.getNSplitter()]; c"V"zg22  
nEndPos = new long[bean.getNSplitter()]; EF}\brD1  
} r8rgY42  
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} tKx~1-  
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public void run() n QZwC  
{ O#~yKqB  
//获得文件长度 /quc}"__  
//分割文件 `yXg{lk  
//实例FileSplitterFetch ][h%UrV  
//启动FileSplitterFetch线程 (
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//等待子线程返回 {xB!EQ"  
try{ aPfO$b:  
if(bFirst) zFws:_ i  
{ I%X6T@P  
nFileLength = getFileSize(); j2.|ln"!  
if(nFileLength == -1) O{G?;H$  
{ YPK(be_|I  
System.err.println("File Length is not known!"); K;Uvb(m{&  
} |5~#&v_  
else if(nFileLength == -2) j94=hJVKi  
{ BBRR
)  
System.err.println("File is not access!"); KNpl:g3{<Q  
} +LZLy9iKt  
else g:D>.lKd  
{ -)]Yr #Q  
for(int i=0;i<nStartPos.length;i++) e
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{ L Mbn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [{<`o5qR  
} [-k  
for(int i=0;i<nEndPos.length-1;i++) x_6[P2"PP  
{ ?o4C;  
nEndPos = nStartPos[i+1]; 2%@4]  
} Tx=-Bb~;  
nEndPos[nEndPos.length-1] = nFileLength; wb5baY9  
} *
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} fg!__Rdi  
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)c83/= <v  
//启动子线程 foF({4q7b^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %.Fi4}+O  
for(int i=0;i<nStartPos.length;i++) i,E{f  
{ wQH<gJE/:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rc>4vB_ha  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EZy)A$|  
nStartPos,nEndPos,i); YY((V@|K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zH4D8@[7O  
fileSplitterFetch.start(); ?{|q5n  
} 6?mibvK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +[AQUc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); % X+:o]T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RLynEV;]  
nEndPos = " + nFileLength); ~u!|qM  
// fileSplitterFetch[nPos.length-1].start();
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//等待子线程结束 V2?=4mb  
//int count = 0; #ASz;$P  
//是否结束while循环 o]` *M|  
boolean breakWhile = false; djQH1^(IU  
S)k*?dQ##R  
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while(!bStop) >CgTs  
{ 1i"WDu*h3  
write_nPos(); 5k3n\sqZA  
Utility.sleep(500); 2LL'J7  
breakWhile = true; {3p4:*}  
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for(int i=0;i<nStartPos.length;i++) ,p@y] cr  
{ *,)Md[  
if(!fileSplitterFetch.bDownOver) FLCexlv^  
{ \H~T>j{N  
breakWhile = false; t#/YN.@r  
break;  ZrxD`1L  
} P[#e/qnXu|  
} b#Z{{eLny  
if(breakWhile) V>%rv'G8  
break; Ic:(Gi- %  
,I$`-$_'  
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//count++; WZejp}x  
//if(count>4) gJXq^~-hd  
// siteStop(); 9ni1f{k  
} SSg8}m5)Q  
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System.err.println("文件下载结束！"); '&R2U_  
} @=Uh',F  
catch(Exception e){e.printStackTrace ();} d(x\^z  
} =:,g  
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//获得文件长度 v ~?qz5:K~  
public long getFileSize() hh)`645=x  
{ B6nX$T4zP  
int nFileLength = -1; '!cCMTj  
try{ (KD RkE|=  
URL url = new URL(siteInfoBean.getSSiteURL()); ksqQM
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6V:U(g  
httpConnection.setRequestProperty("User-Agent","NetFox"); m 3hrb-  
2K6qY)/_  
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int responseCode=httpConnection.getResponseCode(); )?naN  
if(responseCode>=400) o>i4CCU+  
{ B6As,)RjD:  
processErrorCode(responseCode); 4*#18<u5  
return -2; //-2 represent access is error qI9z;_,gNz  
} V-2(?auZd  
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String sHeader; cJ n=  
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for(int i=1;;i++) Apag{Z]^B  
{ L>NL:68yN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9r<J"%*Q  
//Utility.log(in.readLine()); "]x'PI 4J  
sHeader=httpConnection.getHeaderFieldKey(i); Y%aCMP9j~9  
if(sHeader!=null) l^-];|Y  
{ YQ)kRhFA  
if(sHeader.equals("Content-Length")) TG?brgW  
{ 1 ~*7f>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]BZA:dd.G  
break; *NaB#;+|k`  
} =tn)}Y.<e  
} 0c]/bs{}  
else vY}g<*  
break; t?&|8SId  
} I)6+6pm  
} 9dLV96
  
catch(IOException e){e.printStackTrace ();} z`}qkbvi  
catch(Exception e){e.printStackTrace ();} *3FKt&v 0  
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Utility.log(nFileLength); TR`U-= jH,  
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return nFileLength; tBWrL{xLe  
} P[ck84F/  
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{.|CdqwY  
//保存下载信息（文件指针位置） PO^ij2eS  
private void write_nPos() '<xXK@=KEI  
{ "ycJ:Xv49  
try{ 2r4Uh1D~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6=/F$|  
output.writeInt(nStartPos.length); A#<?4&  
for(int i=0;i<nStartPos.length;i++) RnE4<Cy  
{ gp?uHKsM  
// output.writeLong(nPos); 6ex/TySM  
output.writeLong(fileSplitterFetch.nStartPos); : /N0!&7  
output.writeLong(fileSplitterFetch.nEndPos); 9};8?mucr  
} yu|8_<bq  
output.close(); FUb\e-Q=  
} +Q)XH>jh  
catch(IOException e){e.printStackTrace ();} u@M,qo`  
catch(Exception e){e.printStackTrace ();} ]Sz:|%JP1  
} MYvY]Jx3  
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//读取保存的下载信息（文件指针位置） B{#I:Rs9  
private void read_nPos() (gU!=F?#m  
{ T/~f~Zz  
try{ a0E)2vt4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lU\[aNs  
int nCount = input.readInt(); ]^7@}Ce_  
nStartPos = new long[nCount]; h"Q8b}$^)  
nEndPos = new long[nCount]; wv1iSfW  
for(int i=0;i<nStartPos.length;i++) 5m 4P\y^a  
{ =R|HV;9 h  
nStartPos = input.readLong(); ]|ag  
nEndPos = input.readLong();  A,<E\  
} fOGFq1
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input.close(); P>D)7V9Hh  
} Pn1^NUMZJ  
catch(IOException e){e.printStackTrace ();} #A/  
catch(Exception e){e.printStackTrace ();}  'KL0@l  
} v$v-2y'%  
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-  
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private void processErrorCode(int nErrorCode) eJ-xsH*8  
{ p)-^;=<B3  
System.err.println("Error Code : " + nErrorCode); ,^< R{{{-A  
} &h)yro  
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//停止文件下载 +GN(Ug'R  
public void siteStop() ]Q1yNtN  
{ _6hQ %hv8  
bStop = true; ;`{H!w[D  
for(int i=0;i<nStartPos.length;i++) 'GWN~5  
fileSplitterFetch.splitterStop(); |aS.a&vwR  
.!3|&V'<  
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} RSRS wkC  
} 3jU&zw9  
//负责部分文件的抓取 -d/ =5yxL  
**FileSplitterFetch.java d&Zpkbh"  
*/ yx[/|nZDC4  
package NetFox;
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import java.io.*; 2@
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import java.net.*; ML 9' |  
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public class FileSplitterFetch extends Thread { ^uc=f2=>,  
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String sURL; //File URL h,N?Ab'S  
long nStartPos; //File Snippet Start Position i1d'nxk6  
long nEndPos; //File Snippet End Position EME|k{W  
int nThreadID; //Thread's ID ]s'as9s9  
boolean bDownOver = false; //Downing is over Q3~H{)[Kq  
boolean bStop = false; //Stop identical a58H9w"u)  
FileAccessI fileAccessI = null; //File Access interface =y*IfG9b  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eo?bL$A[s  
{ ;igIZ$&  
this.sURL = sURL; |wMN}bq|T  
this.nStartPos = nStart; sll\g  
this.nEndPos = nEnd; ]F~dlH1Wp
 
nThreadID = id; ="H`V V_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :3Ox~o  
} 4pF*"B  
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public void run() \gaw6S>n}  
{ Wn2NMXK  
while(nStartPos < nEndPos && !bStop) ^^$s%{ep"  
{ IEi^kJflU  
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try{ =UQ3HQD  
URL url = new URL(sURL); \}b%E'+_T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vvMT}-!  
httpConnection.setRequestProperty("User-Agent","NetFox"); {JT&w6Jz  
String sProperty = "bytes="+nStartPos+"-"; 2%m BK  
httpConnection.setRequestProperty("RANGE",sProperty); &p@O_0nF  
Utility.log(sProperty); b8UO,fY q  
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InputStream input = httpConnection.getInputStream(); $6 f3F?y7  
//logResponseHead(httpConnection); 1GcE)e!>  
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byte[] b = new byte[1024]; J*M>6Q.)  
int nRead; k4J+J.|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !F$6-0%  
{ gwMNYMI  
nStartPos += fileAccessI.write(b,0,nRead); F$]Pk|,  
//if(nThreadID == 1) 
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d#FQc18v}k  
} ?:q*(EC<  
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Utility.log("Thread " + nThreadID + " is over!"); 73;GW4,  
bDownOver = true; CD~.z7,LC  
//nPos = fileAccessI.write (b,0,nRead); Xx:"4l.w.  
} L="}ErmK  
catch(Exception e){e.printStackTrace ();} >y3=|  
} U
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} h2R::/2.  
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//打印回应的头信息 f+!(k)GWd  
public void logResponseHead(HttpURLConnection con) k9!{IScq  
{ F JyT+  
for(int i=1;;i++) q_58;Bv  
{ (!WD1w
 
String header=con.getHeaderFieldKey(i); n:!_  
if(header!=null) Iefn$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e\L8oOk#r  
Utility.log(header+" : "+con.getHeaderField(header)); YOO+R{4(  
else ?e 4/p  
break;
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} rx|pOz,:  
} G"t5nHY\.  
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public void splitterStop() tWcHb #  
{ bk[!8-b/a  
bStop = true; InI$:kJ  
} \9T7A&  
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} #H~64/  
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/* T>W,'H  
**FileAccess.java ]Y&VT7+Z  
*//文件访问(定位，写) +ZP7{%  
package NetFox; i83OOV$1J  
import java.io.*; ?:0Jav  
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public class FileAccessI implements Serializable{ /)O"l@ }U  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YoFxW5by  
RandomAccessFile oSavedFile; z F;K  
long nPos; Q"#J6@  
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public FileAccessI() throws IOException K|=A:  
{ I&5!=kR  
this("",0); m1AJ{cs  
} om>KU$g  
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public FileAccessI(String sName,long nPos) throws IOException HZZn'u  
{ w0unS`\4  
oSavedFile = new RandomAccessFile(sName,"rw"); |R:'\+E  
this.nPos = nPos; wMN]~|z>  
oSavedFile.seek(nPos); |_U= z;Y  
} >9J:Uo1z  
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public synchronized int write(byte[] b,int nStart,int nLen) .=; ;  
{ 9>#6*/Oa7  
int n = -1; u ^RxD^=L  
try{ LDa1X2N  
oSavedFile.write(b,nStart,nLen); GC'O[q+  
n = nLen; j'K/22  
} Ax}JLPz5'  
catch(IOException e) _@/8gPT*i  
{ j] [,J49L  
e.printStackTrace (); q@2siI~W  
} f*8DCh!r"  
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return n; e+K^Aq  
} BJ(M2|VH  
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} \l3h0R  
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/* TL#3
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**SiteInfoBean.java +"VP-s0  
*/ )`D:F>p*  
package NetFox; 2J;g{95z  
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;A[Q2(w+  
public class SiteInfoBean { $ME)#(  
IE~ |iQ?-  

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private String sSiteURL; //Site's URL #_lDss  
private String sFilePath; //Saved File's Path e>7i_4(C  
private String sFileName; //Saved File's Name 4KrL{Z+}  
private int nSplitter; //Count of Splited Downloading File T6k0>[3xf  
3+bt~J0  
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public SiteInfoBean() <9 ;!3xG  
{//nSplitter的缺省值为5 ?z u8)U  
//default value of nSplitter is 5 ig &Y  
this("","","",5); E4xa[iZ  
} !f6(Zho  
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Y nZiTe@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BsJC0I(  
{ 4X|zmr:A  
sSiteURL= sURL; SX-iAS[<  
sFilePath = sPath; T]p-0?=4vv  
sFileName = sName; po7qmLq  
this.nSplitter = nSpiltter; v*yuE5{  
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} @\I#^X5lv  
8Q+36!  

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public String getSSiteURL() *uvQ\.  
{ Xn\jO>[Ef  
return sSiteURL; #R RRu2  
} :eLVC7'  
wec)Ctj+  
lb1Xsgm{  
public void setSSiteURL(String value) N,U8YO  
{ ;jTN| i'  
sSiteURL = value; 7"xd1l?zz  
} 6S\8$  
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public String getSFilePath() WOf 4o  
{ 4v|W-h"K  
return sFilePath; u>/ TE  
} 61 ~upQaR  
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public void setSFilePath(String value) $u6 3]rypm  
{ '[O;zJN;  
sFilePath = value; h`.&f  
} y18Y:)DkL  
&G$Ucc `  
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public String getSFileName() NW)1#]gg%  
{ gv{ >`AN  
return sFileName; j1HW._G  
} ^y4Z+Gu[  
/|&*QLy  
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public void setSFileName(String value) Fea(zJ_  
{ /JU.?M35  
sFileName = value; mlS$>O_aX  
} G<;*SYAb  
c_l"I9M#r  
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public int getNSplitter() HLHz2-lI  
{ 7})[lL`\s  
return nSplitter; cPc</[x[W  
} ]]j;
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{2"zVt#h  
~.lPEA %%  
public void setNSplitter(int nCount) xA[mm  
{ Q.c\/&  
nSplitter = nCount; ROZF)|l  
} @!d{bQd,  
} *G9V'9  
efE.&]  
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r  
/* :S(ZzY Q  
**Utility.java R_S.tT!  
*/ ?#Q #u|~  
package NetFox; lCHO;7YHX  
*siFj CN<  
-+-_I*(  
public class Utility { ges J/I  
'(jG[ry&T  
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public Utility() QnX(V[  
{ %C_HXr@  
',5ky{  
=zs`#-^8  
} _/<x  
j^2j&Ta  
//线程睡眠 {+Cy U!O  
public static void sleep(int nSecond) QoH6  
{ @49S`  
try{ X+]G-  
Thread.sleep(nSecond); 3%=~)7cF  
} zT?D<XW>1  
catch(Exception e) DrK{}uM  
{ y Fq&8 x<X  
e.printStackTrace (); I ?.^ho  
} LvYB7<zk>  
} m/EFHS49  
4#hSJ(~7S  
//日志 cDkf qcC  
public static void log(String sMsg) dzrio-QU~  
{ r^ ZEImjc  
System.err.println(sMsg); D=
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} K8Y=S12Ti  
mBON$sF|  
b<gr@WF  
public static void log(int sMsg) >!)DM]Ri  
{ Jma1N;d  
System.err.println(sMsg); P\)iZiGc  
} l_
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} g_COp"!~9  
<dhM\^[  
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/* FH+s s
!  
**TestMethod.java \v)+.m?n  
*/ gCY';\f!  
package NetFox; v0jgki4t  
] {HI?V  
/%A*aGyIc  
public class TestMethod { ZbAcO/  
[Hh9a;.*}h  
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public TestMethod() e'b(gD}
 
{ ///xx/weblogic60b2_win.exe W-zP/]Dh  
try{ mF^v~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /J6rv((  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0}quG^%_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aPbE;" f  
fileFetch.start(); mvT(.R ..s  
} O/(xj2~$J  
catch(Exception e){e.printStackTrace ();} vTw>JNVI  
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p,i[W.dy.'  
} jPW#(3hoE  
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[RTs[3E^  
public static void main(String[] args) @@%.t|=  
{ '}bgLv  
new TestMethod(); ;cN{a&  
} >[=^_8M  
} 9j:"J` '  
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