http断点续传简单实现（java)

/* #g,JNJ}  
**SiteFileFetch.java ("(:wYR%  
*/ >%jQw.  
package NetFox; <Z%iP{  
import java.io.*; AfmGA9  
import java.net.*; pC 5J '@  
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public class SiteFileFetch extends Thread { >5C|i-HX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #~J)?JL  
long[] nStartPos; //开始位置 4:\1S~WW  
long[] nEndPos; //结束位置 ~e<l`rg#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7kmU/(8  
long nFileLength; //文件长度 d<mj=V@bd  
boolean bFirst = true; //是否第一次取文件 Bbuy y  
boolean bStop = false; //停止标志 ^c?2n  
File tmpFile; //文件下载的临时信息 o~7~S  
DataOutputStream output; //输出到文件的输出流 (=:9pbP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Kn~f$1  
public SiteFileFetch(SiteInfoBean bean) throws IOException W=YFe<Q  
{ %Od?(m"&  
siteInfoBean = bean; )G$/II9d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n"YY:Gm;8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nbM[?=WS  
if(tmpFile.exists ()) ycAQHY~n  
{ GtcY){7  
bFirst = false; VfAC&3%M
 
read_nPos();  9?c0cwP?  
} tRU+6D <w  
else _[|~(lDJl  
{ -V@vY42  
nStartPos = new long[bean.getNSplitter()]; uM"G)$I\  
nEndPos = new long[bean.getNSplitter()]; 'PW~4f/m  
} (S/f!Dk&3  
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} S]3K5Z|  
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public void run() ZuIr=`"j  
{ 4B>N[#-0=  
//获得文件长度 8>" vAEf  
//分割文件 bdh6ii  
//实例FileSplitterFetch #rSm;'%,  
//启动FileSplitterFetch线程  QDCu  
//等待子线程返回 3@XkO  
try{ !6yoD  
if(bFirst) 6gz !K"S  
{ $j61IL3+  
nFileLength = getFileSize(); [@"~'fu0  
if(nFileLength == -1) I}JC~=`j  
{ nX(2&<  
System.err.println("File Length is not known!"); >`Xikn(  
} oNHbQ&h  
else if(nFileLength == -2) Ua^#.K  
{ hl`4_`3y  
System.err.println("File is not access!"); h}PeXnRU  
} qN h:;`  
else },9Hq~TA  
{ !{'C.sb?~  
for(int i=0;i<nStartPos.length;i++) 3F fS2we  
{ V8`o71p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -xg$qvK  
} 9 cU]@j}2  
for(int i=0;i<nEndPos.length-1;i++) KQ0Zy  
{ !#l>+9  
nEndPos = nStartPos[i+1]; AD_RU_a9  
} l{tpFu9v  
nEndPos[nEndPos.length-1] = nFileLength; *x[ZN\$`Y  
} Jq0aDf f  
} LWG%]m|C  
ziUEA>m*/  
(tQ#('(w  
//启动子线程 "G. L)oD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9[yW&t;#  
for(int i=0;i<nStartPos.length;i++)
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{ N!R>L{H>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f' |JLhs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TEQs\d  
nStartPos,nEndPos,i); lYz{#UX}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VF8pH<  
fileSplitterFetch.start(); {%g]Ym=  
} l/?Jp+]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %JUD54bBt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mx`QBJ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $ ?ayE  
nEndPos = " + nFileLength); OW}ny  
// fileSplitterFetch[nPos.length-1].start(); >bQ'*!  
-/ 5" Py  
l":\@rm`  
//等待子线程结束 M<h2+0(il  
//int count = 0; fmqHWu*wG  
//是否结束while循环
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boolean breakWhile = false; TmI~P+5w  
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while(!bStop) QD6<sw@]P  
{ ~z;G$jd  
write_nPos(); h-)tWJ c  
Utility.sleep(500); 'ii5pxeNI  
breakWhile = true; S\$=b_.  
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for(int i=0;i<nStartPos.length;i++) alr'If@7  
{ .gZ1}2GF=  
if(!fileSplitterFetch.bDownOver) )4h4ql W  
{ mn5y]:;`  
breakWhile = false; Rr>nka)U  
break; < cNJrer  
} L\)GPTo!x  
} Y!!w*G9b  
if(breakWhile) PfF5@W;E;  
break; h=<x%sie  
,x(?7ZW>  
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//count++; C/3
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//if(count>4) . W ~&d_n  
// siteStop(); eK8y'VY  
} "{TVd>9_  
~
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System.err.println("文件下载结束！"); cp| q  
} T#M_2qJ1=  
catch(Exception e){e.printStackTrace ();} =r1-M.*a.M  
} L_@P fI
 
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//获得文件长度 r Uau??  
public long getFileSize() x-E@[=  
{ =}F}XSvXH  
int nFileLength = -1; d8N{sT  
try{ ,,}& Q%5  
URL url = new URL(siteInfoBean.getSSiteURL()); l~mC$>f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qs\m"yx  
httpConnection.setRequestProperty("User-Agent","NetFox"); GXk]u  
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int responseCode=httpConnection.getResponseCode(); 9(-f)$u  
if(responseCode>=400) K9\r2w'T'  
{ >`E (K X  
processErrorCode(responseCode); luvxwved  
return -2; //-2 represent access is error "`6pF8k  
} uV=ZGr#o  
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String sHeader; J?R\qEq%  
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for(int i=1;;i++) 7)-uYi] dA  
{ wZe>}1t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |BA&ixHe~C  
//Utility.log(in.readLine()); 5MX7V4ist  
sHeader=httpConnection.getHeaderFieldKey(i); Zb&5)&'
X  
if(sHeader!=null) i>j(Dsv  
{ \&XtPQ  
if(sHeader.equals("Content-Length")) 
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{ d?6\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?1afW)`a.v  
break; !(H RP9  
} 6<t<hP_3O  
} xI>HY9i)  
else S UBrFsA  
break; I+GP`=\  
} 3[*x'"Q;H  
} %(}%#-X  
catch(IOException e){e.printStackTrace ();} )B$Uo,1  
catch(Exception e){e.printStackTrace ();} "=Xky,k  
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Utility.log(nFileLength); xofxE4.  
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return nFileLength; +~n"@ /  
} /ka "YU  
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vp|.x |@  
//保存下载信息（文件指针位置） uY;7&Lw y1  
private void write_nPos() )u?^w  
{ cgV5{|P  
try{ c&"OhzzJK'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ET\>cxSp  
output.writeInt(nStartPos.length); M`D`-vv  
for(int i=0;i<nStartPos.length;i++) 4p6\8eytq.  
{ 8+mu'RZ X  
// output.writeLong(nPos); Hfo/\\  
output.writeLong(fileSplitterFetch.nStartPos); |_\q5?S  
output.writeLong(fileSplitterFetch.nEndPos);
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} {>h,@  
output.close(); ],|
;  
} f\u5=!kjN  
catch(IOException e){e.printStackTrace ();} 9i`MUE1Sh  
catch(Exception e){e.printStackTrace ();} !*!i&0QC~R  
} fn3D
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@W.0YU0|J  
//读取保存的下载信息（文件指针位置） D6fGr$(N%  
private void read_nPos() BJP^?FUd=,  
{ }$oZZKS  
try{ \R.Fmeko  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,<O|#`?"@G  
int nCount = input.readInt(); k vF[d{l
 
nStartPos = new long[nCount]; W@t{pXwLv  
nEndPos = new long[nCount]; 0RF<:9@x2  
for(int i=0;i<nStartPos.length;i++) 1SG^g*mf  
{ zbZN-j#  
nStartPos = input.readLong(); g0M/Sv  
nEndPos = input.readLong(); V8947h|&  
} ,e@707d`\  
input.close(); ;mauA#vd  
} c:u2a/Q?  
catch(IOException e){e.printStackTrace ();} y{9<>28  
catch(Exception e){e.printStackTrace ();} [pzo[0G 'v  
} \= 
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private void processErrorCode(int nErrorCode) seS)`@n  
{ i:sb_U+M  
System.err.println("Error Code : " + nErrorCode); ? oQ_qleuo  
} Y;1J`oT  
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//停止文件下载 K*aGz8N  
public void siteStop() umI6# Vd`=  
{ 4mci@1K#^  
bStop = true; U&OE*dq  
for(int i=0;i<nStartPos.length;i++) Eemk2>iP?  
fileSplitterFetch.splitterStop(); >U62vX"  
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} oL
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} v"V?  
//负责部分文件的抓取 ~+&Z4CYb  
**FileSplitterFetch.java n_S)9C'=  
*/ 9t"/@CH{  
package NetFox; NaC}KI`  
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import java.io.*; gPY Cw?zQ  
import java.net.*; icXeB_&cS  
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public class FileSplitterFetch extends Thread { )(DX]Tr`  
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String sURL; //File URL I`[s(C>3@  
long nStartPos; //File Snippet Start Position e"]DIy4s  
long nEndPos; //File Snippet End Position x0ICpt{;  
int nThreadID; //Thread's ID Qg5-I$0  
boolean bDownOver = false; //Downing is over oF=UjA  
boolean bStop = false; //Stop identical I7HP~v~  
FileAccessI fileAccessI = null; //File Access interface :eL ja*  
t4FaU7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &)F#cVB  
{
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this.sURL = sURL; 11BfJvs:  
this.nStartPos = nStart; oWcBQ|   
this.nEndPos = nEnd; ds<q"S{p  
nThreadID = id; $|H7fn(r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mVEHVz $  
} V38v2LI  
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public void run() XFrgnnt  
{ M|\C@,F]8  
while(nStartPos < nEndPos && !bStop) hgI;^ia  
{ |C3~Q{A  
_?~)B\@~0  
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try{ FW,@.CX  
URL url = new URL(sURL); t.6gyrV7><  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N-<m/RS  
httpConnection.setRequestProperty("User-Agent","NetFox"); +I_p\/J?w/  
String sProperty = "bytes="+nStartPos+"-"; S#f}mb0,  
httpConnection.setRequestProperty("RANGE",sProperty); 8L,i}hIo.  
Utility.log(sProperty); YN($rAkL  
9/4Bx!~A  
 FA#8  
InputStream input = httpConnection.getInputStream(); Cl'3I%$8K  
//logResponseHead(httpConnection); cP&XkAQ  
{,
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byte[] b = new byte[1024]; 2[TssJQ  
int nRead; :P:OQ[$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V0a)9\x(\  
{ *pKj6x  
nStartPos += fileAccessI.write(b,0,nRead); [;qZu`n>  
//if(nThreadID == 1) N Uq'96{Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XdGA8%^cY  
} DgRA\[c  
#`b5kqQm  
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Utility.log("Thread " + nThreadID + " is over!"); X7{ h/^  
bDownOver = true; ;sfk@ec  
//nPos = fileAccessI.write (b,0,nRead); E|5lm  
} rulw6vTB(  
catch(Exception e){e.printStackTrace ();} (Gpk;DD  
} t9+ME|  
} Hpq?I-g<^  
}5a$Ka-  
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//打印回应的头信息 >2@ a\  
public void logResponseHead(HttpURLConnection con) Kvf
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{ N77EM  
for(int i=1;;i++) $][$ e  
{ QP0[  
String header=con.getHeaderFieldKey(i); n 2m!a0;
 
if(header!=null) {ZrB,yK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n> O3p ~  
Utility.log(header+" : "+con.getHeaderField(header)); v#o<. Ig  
else $H2H
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break; (&ABfm/t  
} d vTsbs/6  
} P1Chmg  
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public void splitterStop() Ri&?uCCM  
{ _$YT*o@0J  
bStop = true; $jtXNE?  
} Gp5=
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} sPUn"7  
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s u)AIvF
{  
/* }ikJa  
**FileAccess.java +ZxG<1&  
*//文件访问(定位，写) {9y
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package NetFox; Z2wgfP`  
import java.io.*; )i{B:w\ ^  
=(U&?1R4  
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=  
public class FileAccessI implements Serializable{ gjnTG:}}}+  
_Z
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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 T($6L7 j9  
RandomAccessFile oSavedFile; N&'05uWY}  
long nPos; M,j3z#  
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public FileAccessI() throws IOException %.3]F2_Q  
{ IoI ,IX]i)  
this("",0); 7)y9%-}  
} _6,Tb]  
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public FileAccessI(String sName,long nPos) throws IOException 39zwPoN>  
{ Hjtn*^fo^  
oSavedFile = new RandomAccessFile(sName,"rw"); ,F)9{ <r]  
this.nPos = nPos; t)hAD_sf  
oSavedFile.seek(nPos); m:A1wL4c6  
} GI40Ztms  
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n'-?CMH`  
public synchronized int write(byte[] b,int nStart,int nLen) =TzmhX5  
{ }|Wn6X  
int n = -1; |K
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try{ )^'g2gVK+p  
oSavedFile.write(b,nStart,nLen); Z(=UZI?  
n = nLen; a1nj}1M%  
} S66..sa  
catch(IOException e) {~RS$ |  
{ b\^q9fy  
e.printStackTrace (); s wIJmA  
} O5?Gv??@  
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return n; I/ q>c2Pw$  
} !33)6*s  
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} ; OpN&q+  
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/* jQc.@^#+x  
**SiteInfoBean.java &/7D4!N]  
*/ 7^|,l  
package NetFox; ~&?{hd.  
u{_jweZ  
9gLUM$Kd  
public class SiteInfoBean { h*JzJ0X  
/>,Tq!i\4}  
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private String sSiteURL; //Site's URL X\a*q]"_  
private String sFilePath; //Saved File's Path c+^#(OB  
private String sFileName; //Saved File's Name _CDl9pP36#  
private int nSplitter; //Count of Splited Downloading File @Pt,N qj
:  
=oPc\VYW  
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public SiteInfoBean() jbU=D:|  
{//nSplitter的缺省值为5 >P/Nb]C  
//default value of nSplitter is 5 1 ynjDin<  
this("","","",5); T1&^IO-F7$  
} 3Wl,T5}{  
8
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g,0u_$U  
{ JGB 9Z   
sSiteURL= sURL; 1Y-m=~J7  
sFilePath = sPath; pRAdo="  
sFileName = sName; %S
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this.nSplitter = nSpiltter;
{
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_  

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} ]^j'2nJv0  
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public String getSSiteURL() [= GVK  
{ Y<vsMf_U  
return sSiteURL; YR{%pZp  
} ia!b0*<   
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public void setSSiteURL(String value) @4'bI)  
{ U60jkzIRH  
sSiteURL = value; */|Vyp-  
} 6^oQ8unmS  
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public String getSFilePath() J*lKXFq7  
{ sU/R$Nbr  
return sFilePath; 7HpfHqJ7  
} =ca<..yh[d  
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public void setSFilePath(String value) L6xLD X7y  
{ *7ggw[~  
sFilePath = value; Kf.G'v46  
} |9;6Cp  
,EAf/2C  
!&3iZQGWv  
public String getSFileName() ~is$Onf99#  
{ q:y_#r"_y  
return sFileName; /lC&'hT  
} sUfYEVjr  
>|"mhNF  
 !IZbMn6  
public void setSFileName(String value) PMdvBOtS`  
{ P?y3YxS  
sFileName = value; D};zPf@!p  
} 7^fpbrj  
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public int getNSplitter() $ON4nx  
{ abHW[VP9  
return nSplitter; Vu%XoI)<KY  
} vBMuVpzO  
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public void setNSplitter(int nCount) 6%p$C oR  
{ ^&AhWm7\  
nSplitter = nCount; wc3
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} \,w*K'B_Y  
} U%Kv}s/(F{  
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O:=%{/6&D  
/* n9;z=   
**Utility.java p m4g),s  
*/ acSm+t  
package NetFox; t Z_ni}  
sg.8Sd"]7  
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public class Utility { t3#My2=  
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public Utility() ,~R`@5+  
{ kHO2&"6  
+@'{  
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} |M*jo<C  
,ZpcvK/S  
//线程睡眠 dFd^@b  
public static void sleep(int nSecond) OX"^a$  
{ vZgV/?'z  
try{ ^V DJGBk  
Thread.sleep(nSecond); n~1'M/wh  
}
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catch(Exception e) 9@Iz:!oqb  
{ '`-W!g[ >  
e.printStackTrace (); AhZ`hj
 
} h6*&1r  
} `A]CdgA  
%uuh+@/&yz  
//日志 )JO#Z(  
public static void log(String sMsg) KuU]enC3  
{ %:v59:i}  
System.err.println(sMsg); @R5jUPUVV  
} kWF/SsE  
*^BW[C/CTR  
6m.ChlO/  
public static void log(int sMsg) "[PxLq5  
{ Zu4|
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System.err.println(sMsg); L|y4u;-Q  
} F{:ZHCm  
} 0XrB+nt  
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CQf<En|1  
/* 9`"o,wGX3  
**TestMethod.java I)xB I~x  
*/ e}x}
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package NetFox; r/X4Hy0!lT  
|ZEZ@y^  
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public class TestMethod { z7[TgL7  
]Qo.X~]  
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public TestMethod() ~?V+^<P  
{ ///xx/weblogic60b2_win.exe ?_\t7f  
try{ >^1|Mg/!>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tSST.o3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [}7j0&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \2?p  
fileFetch.start(); ISQC{K']J  
} }Pm>mQZ},  
catch(Exception e){e.printStackTrace ();} -S
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} .Z,3:3,]  
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public static void main(String[] args) 2?",2x09  
{ oYYns%r}{  
new TestMethod(); _
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} }pE8G#O&  
} \htL\m^$9  
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