http断点续传简单实现（java)

/* U>5^:%3  
**SiteFileFetch.java %L|fTndKH  
*/ 4;`z6\u9-  
package NetFox; ~/OY1~c  
import java.io.*; w$
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import java.net.*; 'g v0;L  
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public class SiteFileFetch extends Thread { a[{$4JpK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1ni+)p>]  
long[] nStartPos; //开始位置 6jE.X  
long[] nEndPos; //结束位置 &OR(]Wt0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;$p!dI\-Q  
long nFileLength; //文件长度 IUMv{2C  
boolean bFirst = true; //是否第一次取文件 Pwh}hG1sa  
boolean bStop = false; //停止标志 D:P(;  
File tmpFile; //文件下载的临时信息 qpQ;,8X-"  
DataOutputStream output; //输出到文件的输出流 iOL$|Z(  
)>a~%~:  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） RQ+,7Ir  
public SiteFileFetch(SiteInfoBean bean) throws IOException !V|{(>+<  
{ F>;Wbk&[|  
siteInfoBean = bean; 8PI%Z6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d)%WaM%V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SX4*804a_  
if(tmpFile.exists ()) A#U! KX  
{ Koa9W>!  
bFirst = false; )e(<YST  
read_nPos(); A;AQw  
} mxNd
  
else x#{!hL 5G  
{ 5K vp%  
nStartPos = new long[bean.getNSplitter()]; '/Aq2  
nEndPos = new long[bean.getNSplitter()]; @@d_F<Ym[  
} #UGSn:D<i  
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} 7FX4|]  
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public void run() @]uqC~a^  
{ g*k)
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//获得文件长度 [ATJ! O  
//分割文件 /t5)&  
//实例FileSplitterFetch J[/WBVFDf  
//启动FileSplitterFetch线程 OB>Hiy   
//等待子线程返回 S-t#d7'B  
try{ AD?zBg Zu  
if(bFirst) O'4G'H)   
{ |)x7qy`  
nFileLength = getFileSize(); Ek+R  
if(nFileLength == -1) s$Vl">9#  
{ 0U42QEG2  
System.err.println("File Length is not known!"); @yp0WB  
} $8^Hkxy  
else if(nFileLength == -2) /wDf,Hduz  
{ GDu^P+^  
System.err.println("File is not access!"); }[
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} qqDg2,Yb  
else Z\ hcK:  
{ )O'LE&kQ|  
for(int i=0;i<nStartPos.length;i++) {f06Ki  
{ Gxr\a2Z&r%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I0XJ&P%  
} ;m7V]h? R  
for(int i=0;i<nEndPos.length-1;i++) >$q   
{ :a wt7lqv  
nEndPos = nStartPos[i+1]; 17hoX4T  
} ZTmy}@l  
nEndPos[nEndPos.length-1] = nFileLength; s'HsLe0|  
} @9/I^Zk  
} d/_D|ivZ=  
ki1(b]rf  
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//启动子线程 '9\cIni0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v9(5HY  
for(int i=0;i<nStartPos.length;i++) RZ6y5  
{ x*OdMr\n8?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Eq-+g1a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t]K20(FSN  
nStartPos,nEndPos,i); oR#W@OK@is  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }:
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fileSplitterFetch.start(); U>tR:)  
} $;v! ,>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?(ORk|)kU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Zue3Z{31T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O
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nEndPos = " + nFileLength); <Gpji5f2  
// fileSplitterFetch[nPos.length-1].start(); $dfc@Fn^x  
T//xxH]w-  
kn3w6]  
//等待子线程结束 RELNWr  
//int count = 0; <4rnOQ:  
//是否结束while循环 *aErwGLB8  
boolean breakWhile = false; .W]k8N E  
l!ow\ZuQBF  
BN*:*cmUl  
while(!bStop) l7`{O/hN  
{ St5;X&Q  
write_nPos(); [>ghs_?dZ  
Utility.sleep(500); 77\+V 0cF  
breakWhile = true; u\LNJo| B  
1$Hou   
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for(int i=0;i<nStartPos.length;i++) !*]i3 ,{7v  
{ 4DL;Y  
if(!fileSplitterFetch.bDownOver) }c G)$E  
{ Q/o,2R  
breakWhile = false; |>Q>d8|k  
break; ]zx%"SUM  
} h@RpS8!Bi  
} YsmRY=3  
if(breakWhile) Sk{skvd;  
break; k^ <]:B  
4,y7a=qf3  
f*%kHfaXgN  
//count++; Fz#@[1,  
//if(count>4) >zJHvb)b\  
// siteStop(); OIKx:&uIk  
} r+#{\~r7T  
x2v0cR"KL  
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System.err.println("文件下载结束！"); p]L]=-(qI  
} [!uzXVS3  
catch(Exception e){e.printStackTrace ();} |r~u7U\  
} V$ZclV2:Ih  
|_?e.}K  
>XtfT'  
//获得文件长度 5 `1  
public long getFileSize() gnJ8tuS  
{ AM+5_'S,  
int nFileLength = -1; jG>W+lq  
try{ 9#9 UzKX#  
URL url = new URL(siteInfoBean.getSSiteURL()); @gN"Q\;F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O2
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httpConnection.setRequestProperty("User-Agent","NetFox"); Avw=*ZW  
///Lg{ie  
96w2qgc2  
int responseCode=httpConnection.getResponseCode(); bK:U:vpYm  
if(responseCode>=400) A8f.h5~9  
{ [9 MH"\  
processErrorCode(responseCode); <vcU5 .K.  
return -2; //-2 represent access is error xn*$Ty+  
} y#Dh)~|k  
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String sHeader;  VAiJL  
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for(int i=1;;i++) ?/YABY}L  
{ 4Ly>x>b<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4r(0+SO  
//Utility.log(in.readLine()); l
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sHeader=httpConnection.getHeaderFieldKey(i); v+LJx   
if(sHeader!=null) L/"MRQ"  
{ T-N>w;P  
if(sHeader.equals("Content-Length")) JP4DV=}L  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ET.jjV  
break; c)#P}Ai  
} l5-[a  
} !<M eWo  
else )JzY%a SP  
break; uzdPA'u  
} T^ktfgXq  
} :)#;0o5  
catch(IOException e){e.printStackTrace ();} $z=%e#(!I  
catch(Exception e){e.printStackTrace ();} 7}&:07U  
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Utility.log(nFileLength); F` ybe\  
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return nFileLength; BpIyw  
} 4]r_K2.cc  
M!,H0(@G  
dJR[9T_OF  
//保存下载信息（文件指针位置） AYnPxiW|  
private void write_nPos() ?I=1T.  
{ #Ha:O,|  
try{ ) lUS'I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); os5$(  
output.writeInt(nStartPos.length); Vg'R=+Wb  
for(int i=0;i<nStartPos.length;i++) &Ym):pc  
{ m|q,ixg  
// output.writeLong(nPos); (~DW_+?]'  
output.writeLong(fileSplitterFetch.nStartPos); 9w-\K]  
output.writeLong(fileSplitterFetch.nEndPos); *
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} 2u$-(JfoS  
output.close(); ,)`_?^\$f  
} %}@iz(*}>  
catch(IOException e){e.printStackTrace ();} i >3`V6  
catch(Exception e){e.printStackTrace ();} ?W'z5'|  
} `O6#-<>  
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//读取保存的下载信息（文件指针位置） }r,M(Zr  
private void read_nPos() rDFrreQP  
{ t2,II\Kl  
try{ :^y!z1\2(7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6!_Wo\_%  
int nCount = input.readInt(); qcs) p  
nStartPos = new long[nCount]; &>qUT]w  
nEndPos = new long[nCount]; }<WJR Y6j  
for(int i=0;i<nStartPos.length;i++) 5az%yS  
{ GDLi?3q  
nStartPos = input.readLong(); }{F)Ren  
nEndPos = input.readLong(); ;7\Fx8"s[  
} :[<Y#EX.  
input.close(); 4.,EKw3  
} fAJyD`]Z  
catch(IOException e){e.printStackTrace ();} -`'|z+V  
catch(Exception e){e.printStackTrace ();} o"JHB  
} +,spC`M6h  
7RT{RE  
 ]~;*9`:  
private void processErrorCode(int nErrorCode) 6SCjlaGW5  
{ $^Xxn.B9  
System.err.println("Error Code : " + nErrorCode); [R4#bl  
} THwM',6  
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i$y=tJehi  
//停止文件下载 Tu(:?  
public void siteStop() F/2cQ.u2  
{ Ij(d
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bStop = true; Z0&^(Fb  
for(int i=0;i<nStartPos.length;i++) im*sSz 0 (  
fileSplitterFetch.splitterStop(); "c[>>t  
|va@&;#wf  
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} #)S}z+I  
} b_Y+XXb<  
//负责部分文件的抓取 mywxV  
**FileSplitterFetch.java ?`TJ0("z"  
*/ S+06p
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package NetFox; u8 k^\Do  
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import java.io.*; 4AhFE@  
import java.net.*; t'F$/m
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public class FileSplitterFetch extends Thread { Y<;C>Rs  
!$HuH6_[  
&K]|{1+  
String sURL; //File URL 6No.2Oo  
long nStartPos; //File Snippet Start Position _3 [E$Lg  
long nEndPos; //File Snippet End Position I&|8 qx#  
int nThreadID; //Thread's ID S*}GW-)oA  
boolean bDownOver = false; //Downing is over x/1FQ>n:9  
boolean bStop = false; //Stop identical t>]W+Lx#  
FileAccessI fileAccessI = null; //File Access interface K/(LF}  
07^.Z[(pCt  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4`~OxL  
{ gs2qLb  
this.sURL = sURL; R@WW@ Of  
this.nStartPos = nStart; /,7#%D  
this.nEndPos = nEnd; 'q9Ejig  
nThreadID = id; ]Q^8 9?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ])pX)(a  
} -6 v?iiZr  
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public void run() &/
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{ Uj 3{c  
while(nStartPos < nEndPos && !bStop) \yymp70w  
{ %|@?)[;  
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try{ yq3"VFh3d  
URL url = new URL(sURL); 9^SrOW6~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W(ZEqH2  
httpConnection.setRequestProperty("User-Agent","NetFox"); jM*wm~4>@  
String sProperty = "bytes="+nStartPos+"-"; #O^zA`D   
httpConnection.setRequestProperty("RANGE",sProperty); .f!'>_  
Utility.log(sProperty); MS SHMR  
^?%ThPo_  
<
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InputStream input = httpConnection.getInputStream(); ve#[LBOC8  
//logResponseHead(httpConnection); nb5%a  
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byte[] b = new byte[1024]; 0wBr_b!  
int nRead; ;Xidv9
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JmF`5  
{ J!rZskd  
nStartPos += fileAccessI.write(b,0,nRead); -'W:P'BG  
//if(nThreadID == 1) 7({.kD6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $o\Uq  
} ^<yM0'0t  
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Utility.log("Thread " + nThreadID + " is over!"); j@Us7Q)A(  
bDownOver = true; nkkGJV!  
//nPos = fileAccessI.write (b,0,nRead); suj}A  
} GmGq69]J*  
catch(Exception e){e.printStackTrace ();} n;b9f|&z  
} fZd~},X  
} :+DAzjwO<  
:?%_JM5U  
>fR#U"KPAB  
//打印回应的头信息 b=Sl`&A  
public void logResponseHead(HttpURLConnection con) mR{%f?B  
{ Q[O U`
  
for(int i=1;;i++) BcGQpv&x  
{ BJ/#V)  
String header=con.getHeaderFieldKey(i); 4ri)%dl1  
if(header!=null) 9]8M{L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WY~
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Utility.log(header+" : "+con.getHeaderField(header)); yC=vTzzp  
else 7L:R&W6  
break; 8&f"")

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} $0iN43WSQ  
} Y@%6*uTLa  
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public void splitterStop() Vo2fr
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{ r3{o_w  
bStop = true; w_J`29uc  
} >BQF<  
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} DPtyCgH  
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/* .Lu=16  
**FileAccess.java [76mgj!K  
*//文件访问(定位，写) f{Y|FjPp=E  
package NetFox; cl7+DAE  
import java.io.*; zck |jhJ6  
f<'&_*7,|t  
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public class FileAccessI implements Serializable{ R}+/jh2O|  
zZh`go02E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lR^dT4  
RandomAccessFile oSavedFile; z8"=W,2  
long nPos; |V~P6o(/  
*&2
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public FileAccessI() throws IOException <db/. A3  
{ t_VHw'~"  
this("",0); :* /``  
} C1rCKKh  
d`n
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r@<;  
public FileAccessI(String sName,long nPos) throws IOException 6nSk,yE'hE  
{ B 9Mwj:)}
 
oSavedFile = new RandomAccessFile(sName,"rw"); $kz5)vj "  
this.nPos = nPos; ~O 6~',KD  
oSavedFile.seek(nPos); K6oXnz}  
} @x J^JcE  
!V-SV`+X  
&Y=NUDt_  
public synchronized int write(byte[] b,int nStart,int nLen) fR[!=-6^f  
{ 17Gdu[E  
int n = -1; ?h3Ow`1G  
try{ m<f{7]fi5  
oSavedFile.write(b,nStart,nLen); d<b,LD^  
n = nLen; E:E&Wv?r  
} =
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catch(IOException e) `Zi#rr|)L  
{ YV940A-n  
e.printStackTrace (); K+$c,1wb  
} {4m"S7O  
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return n; A0X0t  
} O}D
8  

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} `U1%d7[vY  
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/* DVcu*UVw  
**SiteInfoBean.java n)7icSc  
*/ G-(c+6Mn  
package NetFox; )?bb]hZg?O  
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public class SiteInfoBean { hCvn(f  
W=\dsdnu*  
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private String sSiteURL; //Site's URL omA*XXUx=8  
private String sFilePath; //Saved File's Path `U3  
private String sFileName; //Saved File's Name Fi/G, [q  
private int nSplitter; //Count of Splited Downloading File |O9=C`G_  
Mqtp}<*@-  
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public SiteInfoBean() ?W|IC8~d')  
{//nSplitter的缺省值为5 MHYf8HN  
//default value of nSplitter is 5 2,;t%GB  
this("","","",5); $B?7u@>,  
} D5m\u$~V  
VfcQibm  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +=k|(8Js#  
{ =5M>\vt]  
sSiteURL= sURL; dJ^`9W  
sFilePath = sPath; KUyJ"q<W  
sFileName = sName; /a|NGh%  
this.nSplitter = nSpiltter; h^*{chm]  
<"+C<[n.  
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} KRZV9AJ  
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public String getSSiteURL() NGY I%:  
{ qi2dTB  
return sSiteURL; r*wKYb  
} F]*-i 55S  
7&)F;;H  
k9xKaJ%1  
public void setSSiteURL(String value) cj<@~[uw  
{ gAY2|/,  
sSiteURL = value; KxwLKaImI  
} !gf3%!%  
UVJ(iNK"  
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public String getSFilePath() 0cUt"(]  
{ swFOh5z  
return sFilePath; ~`E4E  
} B^?XE(.  
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public void setSFilePath(String value) ,GnU]f  
{ fO>~V1  
sFilePath = value; g:M7/- "  
} b]#d04]  
!S-U8KI|  
[ d7]&i}*|  
public String getSFileName() 1[`<JCFClc  
{ c7IR06E  
return sFileName; |u;PU`
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} %Ab_PAw  
se HbwO3 b  
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public void setSFileName(String value) ZG<!^tj  
{ pd3&AsU  
sFileName = value; "J{zfWr  
} a4RFn\4?  
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public int getNSplitter() 5z ^UQq  
{ 9%14k  
return nSplitter; ~{G:,|`  
} |uBC0f  
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1T,PC?vr{  
public void setNSplitter(int nCount) _l=  
{ UiZp-Y%ki  
nSplitter = nCount; i(iP}:3  
} ?(8%S
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} y?#J`o- O  
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g
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/* lkg*AAR?'  
**Utility.java Z[S+L"0  
*/ hyfnIb@~}  
package NetFox; PZRn6Tc  
.{a2z*o  
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public class Utility { rOb"S*  

'A!/pUML  
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public Utility() /&as)  
{ rE `}?d  
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} -Dxhq& }Y  
?VP!1O=J  
//线程睡眠 yL x .#kx6  
public static void sleep(int nSecond) vSC0D7BlG  
{ OrEuQ-,i@  
try{ k5;Vl0Ho  
Thread.sleep(nSecond); i6#]$B  
} E+ 3yN\X(  
catch(Exception e) 7Ljj#!`lUp  
{ =/JF-#n/MA  
e.printStackTrace (); 6y,P4O*q  
} _s^:zPl  
} i(yAmo9h  
F:o#  
//日志 k;_KKvQ  
public static void log(String sMsg) EH*ym#Y  
{ zB6u-4^wT  
System.err.println(sMsg); ~/jxB)t  
} o;4e)tK  
~@uY?jr  
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public static void log(int sMsg) hdr}!wV  
{ JV]u(PL  
System.err.println(sMsg); IgVo%)n  
} }pE~85h4M  
} o47   f  
^Z>B/aJq  
xPDA475Cw3  
/* F\=Rm  
**TestMethod.java  Ep\  
*/ k/_8!^:'  
package NetFox; |[owNV>  
7XVzd]jH  
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public class TestMethod { P A6KX5  
CI!Eq&D,  
N`<4:v[P  
public TestMethod() od}EM_  
{ ///xx/weblogic60b2_win.exe vf'cx:m  
try{ OVUs]uK
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :\+{;;a@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O/Y\ps3r  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C?60`^  
fileFetch.start(); RJRq` T|m  
} ?#*
  
catch(Exception e){e.printStackTrace ();} v=*Bb3dt  
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} _iGU|$a  
iL0jpa<}  
wAu[pWD'6;  
public static void main(String[] args) xv$)u<Ve  
{ JXL9Gge  
new TestMethod(); jKj=#O
 
} sArje(5Eo  
} t8AkdSU0  
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