http断点续传简单实现（java)

/* v `;Hd8  
**SiteFileFetch.java ;/!o0:m^I  
*/ ~b6c:db3  
package NetFox; ].@8/. rg  
import java.io.*; </2Cn@  
import java.net.*; <}}u'5;^?x  
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public class SiteFileFetch extends Thread { r(g#3i4Q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {3``B#}  
long[] nStartPos; //开始位置 9
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long[] nEndPos; //结束位置 a._>?rVy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /Nhc|x6zQ  
long nFileLength; //文件长度 ,2mq}u>WU  
boolean bFirst = true; //是否第一次取文件 q<cxmo0
S  
boolean bStop = false; //停止标志 Q3[nS(#Z/=  
File tmpFile; //文件下载的临时信息 r%`3*<ALV)  
DataOutputStream output; //输出到文件的输出流 D@m3bsMwe  
!^Q4ZL,-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;Ao`yC2(v  
public SiteFileFetch(SiteInfoBean bean) throws IOException sRC?l_n;  
{ S)`@)sr  
siteInfoBean = bean; qCm8R@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \c
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if(tmpFile.exists ()) _:KeSskuO  
{ D&D-E~b^  
bFirst = false; N,&bBp  
read_nPos(); S>d7q  
} ">q?(i\  
else 88l{M[B2  
{  X*`b}^T  
nStartPos = new long[bean.getNSplitter()]; 6Z;D`X,5  
nEndPos = new long[bean.getNSplitter()]; "||' -(0  
} Rpxg 5  
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} )IKqO:@  
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public void run() w]US-7  
{ Q$Q:Jm53  
//获得文件长度 |A2o$H  
//分割文件 .+~9 vH  
//实例FileSplitterFetch '^tC|)  
//启动FileSplitterFetch线程 )+f"J$ah  
//等待子线程返回 sc z8`%  
try{ Sre:l'
.  
if(bFirst) )O>M~  
{ Q!h+1fb  
nFileLength = getFileSize(); y)3OQ24  
if(nFileLength == -1) xo{z4W  
{ +; =XiB5R  
System.err.println("File Length is not known!"); /$j,p E=  
} z h%b<  
else if(nFileLength == -2) a@#<qf8g  
{ +#6f)H(P]  
System.err.println("File is not access!"); R xc  
} G9CL}=lJ,  
else J!yK/*sO,  
{ M[L@ej  
for(int i=0;i<nStartPos.length;i++) 0<nW nD,z  
{ s 4n<k]d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i1!Y{  
} &0OH:P%  
for(int i=0;i<nEndPos.length-1;i++) B.#-@  
{ n.1$p  
nEndPos = nStartPos[i+1]; Iv?1XI=  
} o)H| #9h5  
nEndPos[nEndPos.length-1] = nFileLength; w} r mYQ  
} J,k.*t:  
} #,OiZQJC  
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sfsK[c5bm  
//启动子线程 5Z13s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r(g2&}o\  
for(int i=0;i<nStartPos.length;i++) GQ*or>R1  
{ bs)Ro/7}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^%qQ)>I=j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O)`ye5>v  
nStartPos,nEndPos,i); \4uj!LgTb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P,k=u$  
fileSplitterFetch.start(); 1(jx.W3  
} |2I/r$Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MF+F8h>/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x/%/MFK)>8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _;:B@Z  
nEndPos = " + nFileLength); ^vTp.7o~5  
// fileSplitterFetch[nPos.length-1].start(); .xtam 8@  
4!Lj\.!$  
* K0aR!  
//等待子线程结束 f_IsY+@  
//int count = 0; -90X^]  
//是否结束while循环 %/RT}CBBsW  
boolean breakWhile = false; c\rP"y|S};  
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while(!bStop) }jYVB|2  
{ 'fY29Xr^  
write_nPos(); H WFnIUv  
Utility.sleep(500); ;Ehv1{;  
breakWhile = true; m4G))||9Q  
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*++}ll6  
for(int i=0;i<nStartPos.length;i++) svMu85z  
{ 'Kd-A:K2g  
if(!fileSplitterFetch.bDownOver) `bZgw  
{ e)|5P  
breakWhile = false;  mEbj  
break; 'NDr$Qc3  
} EHrr}&  
} KqXPxp^_Al  
if(breakWhile) Lo}zT-F  
break; iL'j9_w,  
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//count++; FMC]KXSd  
//if(count>4) j_SUR)5  
// siteStop(); ]m#*4  
} v+'*
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System.err.println("文件下载结束！"); <,Jx3yq  
} 24 RD  
catch(Exception e){e.printStackTrace ();} 5]2 p>%G  
} Gl9,!"A  
I~,bZA  
_B
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//获得文件长度 _[N*k"  
public long getFileSize() Y$W)JWMY`  
{ [!`5kI  
int nFileLength = -1; )-\qo#0l  
try{ VBK|*Tl  
URL url = new URL(siteInfoBean.getSSiteURL()); ym2"D?P (  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); lOHW9Z  
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int responseCode=httpConnection.getResponseCode(); a&B@F]+  
if(responseCode>=400) '>t'U?7w<  
{ 5`q#~fJ2  
processErrorCode(responseCode); 1?,C d  
return -2; //-2 represent access is error p,7?rI\N  
} ~\ v"xV  
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String sHeader; rW`l1yi*$  
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for(int i=1;;i++) Tb{RQ?Nw'  
{ *C.Kdf3w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U"a7myB+jX  
//Utility.log(in.readLine());
)QI#szv6  
sHeader=httpConnection.getHeaderFieldKey(i); {5c]\{O?[  
if(sHeader!=null) \Npvm49  
{ 8qoA5fW>  
if(sHeader.equals("Content-Length")) r"dR}S.Uf  
{ ;&MnPFmq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C{,Vk/D-0  
break; A|yU'k  
} yh.WTgcW  
} AsI.8"
 
else l/A!ofc#)  
break; Yh{5O3(;  
} Q<(aU{  
} `)Y 5L}c=  
catch(IOException e){e.printStackTrace ();} 6sT(t8[  
catch(Exception e){e.printStackTrace ();} +R"n_6N  
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Utility.log(nFileLength); EBpg  
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return nFileLength; nPH\Lra  
} (R(NEN  
e1hf{:&/G@  
\jAI~|3  
//保存下载信息（文件指针位置） $paE6X^  
private void write_nPos() BRv#`  
{ ^MVOaV65  
try{ n;y[%H!g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z2q!_ ~  
output.writeInt(nStartPos.length); >]2^5C;  
for(int i=0;i<nStartPos.length;i++) }&%&0$%  
{ 61*b|.sl'#  
// output.writeLong(nPos); LN9.Q'@r?  
output.writeLong(fileSplitterFetch.nStartPos); ER:K^ Za  
output.writeLong(fileSplitterFetch.nEndPos); ]PbwG  
} ${`q
!  
output.close(); m;S%RB^~H  
} D2zqDo<+;  
catch(IOException e){e.printStackTrace ();} y|3!E>Up  
catch(Exception e){e.printStackTrace ();} ;|f]e/El  
} !"'@c  
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//读取保存的下载信息（文件指针位置） ,/[1hhP@  
private void read_nPos() Uh^j;s\y  
{ @9\E  
try{ N5b&tJbM0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3w! NTvp  
int nCount = input.readInt(); S}K-\[i?  
nStartPos = new long[nCount];
b)T6%2  
nEndPos = new long[nCount]; f?"909&  
for(int i=0;i<nStartPos.length;i++) 5,R<9FjW  
{ rEs!gGNN  
nStartPos = input.readLong(); d!"gb,ec  
nEndPos = input.readLong(); oOGFg3X  
} =-G4BQ  
input.close(); #:
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} V_KHVul  
catch(IOException e){e.printStackTrace ();} sO)!}#,   
catch(Exception e){e.printStackTrace ();} ca%XA|_J  
} p&HkR^.S  
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private void processErrorCode(int nErrorCode) v=D4O.  
{ 8,:lw3x1  
System.err.println("Error Code : " + nErrorCode); Gn<e&|4>i}  
} pzU:AUW  
'JAe=K H  
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//停止文件下载 pH0MVu(W  
public void siteStop() v&`n}lS  
{ ^{-Z3Yxd  
bStop = true; &p=(0$0&-  
for(int i=0;i<nStartPos.length;i++) +lJD7=%K]Z  
fileSplitterFetch.splitterStop(); DMT2~mh  
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} [LSs|f  
} qtp-w\#S$  
//负责部分文件的抓取 C(}Kfi@6N  
**FileSplitterFetch.java n'@XgUI,  
*/ Rtai?  
package NetFox; }$:ha>  
EtDzmpJR>  
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import java.io.*; ?$b*)<  
import java.net.*; 7[8d-Sf24{  
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public class FileSplitterFetch extends Thread { ZMch2 U8  
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String sURL; //File URL Tg v]30F)  
long nStartPos; //File Snippet Start Position wA6<BujD  
long nEndPos; //File Snippet End Position weIlWxy  
int nThreadID; //Thread's ID )lVplAhZD  
boolean bDownOver = false; //Downing is over smX&B,&@  
boolean bStop = false; //Stop identical 7] 17?s]t,  
FileAccessI fileAccessI = null; //File Access interface WQHlf0]  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xGX U7w:X  
{ hle@= e/n  
this.sURL = sURL; $PTl{  
this.nStartPos = nStart; , ins/-3  
this.nEndPos = nEnd; OI)/J;[-e  
nThreadID = id; J8hH#7WMS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >orDw3xC  
} k7bfgb{  
R?l={N=Wf  
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public void run() PL*kjrLu7  
{ G88g@Exk  
while(nStartPos < nEndPos && !bStop) g=kuM  
{ T28Q(\C:}  
h?&S*)1  
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try{ (s!cd]Qa.  
URL url = new URL(sURL); ]a\HgFp@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s#V:! 7  
httpConnection.setRequestProperty("User-Agent","NetFox"); =p$:vW
 
String sProperty = "bytes="+nStartPos+"-"; k0-,qM#p;X  
httpConnection.setRequestProperty("RANGE",sProperty); S
WMi+)  
Utility.log(sProperty); O`='8'6zW\  
=/qj vY  
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InputStream input = httpConnection.getInputStream(); AO^c=^  
//logResponseHead(httpConnection); `Z~\&r=  
9rQw~B<S  
!\N|$-M  
byte[] b = new byte[1024]; 5\P3JoH:Yg  
int nRead; C-L["O0[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kG]FB.@bG  
{ X5Ff2@."y|  
nStartPos += fileAccessI.write(b,0,nRead); vhu5w#]u*  
//if(nThreadID == 1) ? Glkhf7
(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~0XV[$`L  
} /*) =o+  
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Utility.log("Thread " + nThreadID + " is over!"); ttC+`
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bDownOver = true; ao.v]6a  
//nPos = fileAccessI.write (b,0,nRead); ;l2pdP4
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}
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catch(Exception e){e.printStackTrace ();} 5K %  
} b0"R |d[i  
} LzJNQd'  
:p,DAt}  
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//打印回应的头信息 L BP|  
public void logResponseHead(HttpURLConnection con) {`CmE/`{  
{ &nEQ`3~F  
for(int i=1;;i++) by%k*y  
{ H@pF3gh  
String header=con.getHeaderFieldKey(i); ImVHX~qHJ  
if(header!=null) h2]gA_T`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $+.!(Js"K  
Utility.log(header+" : "+con.getHeaderField(header)); - Ado-'aaS  
else vx8-~Oq{|;  
break; b".e6zev  
} gzDNMM  
} pJ 7="
n  
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public void splitterStop() v&i,}p^M5  
{ q-)Ynp4'  
bStop = true; 8h| 9;%  
} >*aqYNft  
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} G`" 9/
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/}=Bi-  
/* Ei[>%Ah  
**FileAccess.java b4HUgW3Ac  
*//文件访问(定位，写) N}tiaL4  
package NetFox; h (1 }g/  
import java.io.*; zU1[+JJY"{  
)mVpJYt;  
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public class FileAccessI implements Serializable{ ] oh.w  
V!94I2%#x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y! lEGA7  
RandomAccessFile oSavedFile; R%Y#vUmBV{  
long nPos; bez_|fY{T  
}JKK"d}U  
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public FileAccessI() throws IOException <!r0[bKz@  
{ B
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this("",0); 7sci&!.2`  
} ^Q'^9M2)  
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public FileAccessI(String sName,long nPos) throws IOException gADEjr*H  
{ s28rj6q  
oSavedFile = new RandomAccessFile(sName,"rw"); $Jt+>.44  
this.nPos = nPos; `V1D&}H+G  
oSavedFile.seek(nPos); lB0: 4cIj  
} _ IqUp Y  
pg%'_+$~m  
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public synchronized int write(byte[] b,int nStart,int nLen) _m+64qG_8'  
{ (KF=v31_m  
int n = -1; )fo9Qwe  
try{ 2sOV3~bB  
oSavedFile.write(b,nStart,nLen); vZQ'  
n = nLen; -m.SN>V  
} f;k'dqlv  
catch(IOException e) >%~%O`+  
{ *Hnk,?kPq  
e.printStackTrace (); FYe(SV(9  
} k>8,/ AZd  
`n# {}%  
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return n; S]7RGzFe  
} x[,HK{U|t  
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} L(yR"A{FsE  
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/* `~bnshUk  
**SiteInfoBean.java 2^}E!(<  
*/ kAEm#oz=g  
package NetFox; =3Y:DPMB  
yX:*TK4  
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public class SiteInfoBean { 39w|2%(O.  
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private String sSiteURL; //Site's URL i9NUv3#  
private String sFilePath; //Saved File's Path Wq+
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private String sFileName; //Saved File's Name ctv=8SFv(  
private int nSplitter; //Count of Splited Downloading File S9$*w!W  
X0,?~i6Q  
1Fado$# 7  
public SiteInfoBean() n6PXPc  
{//nSplitter的缺省值为5 b`@aiXN)+  
//default value of nSplitter is 5 wX_s./#JJ  
this("","","",5);
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} ov{  
uIG,2u,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6dRxfbL  
{ F9sVMV
 
sSiteURL= sURL; +[MzF EE[  
sFilePath = sPath; <mm.b  
sFileName = sName; A{5^A)$  
this.nSplitter = nSpiltter; *20$u% z2  
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l@x/{0  
} ,Qgxf';+$  
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public String getSSiteURL() ]*8K4n G  
{ .Y8z3O  
return sSiteURL; cax]lO  
} Ylc[ghx  
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public void setSSiteURL(String value) uY,(3x  
{ TNA?fm  
sSiteURL = value; 1rr\l`  
} @O7hY8
",  
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,;aELhMZ  
public String getSFilePath() *(%]|z}]m  
{ 87Sqs1>cw  
return sFilePath; cr{;gP  
} +ht -Bl  
< sJ  
(p2jigP7a[  
public void setSFilePath(String value) XY[uyR4Z  
{ vI<n~FHt  
sFilePath = value; ,4bqjkX5q  
} "T`Q,  
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public String getSFileName() a9CY,+z5B  
{ T+_pmDDN  
return sFileName; nu1s
 
} B 4pJg  
}uJH!@j  
!
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public void setSFileName(String value) - J9K  
{ 'N?,UtG R  
sFileName = value; }H!l@  
} T}ZUw;}BL  
b~khb!]  
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public int getNSplitter() qVOlUH  
{ _raj b1!  
return nSplitter; `K.2&6xc  
} 0XCtw6  
$ e<&7  
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public void setNSplitter(int nCount) y$=$Yc&Ub  
{ uqaP\  
nSplitter = nCount; yF&"'L  
} N
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} YQb43Sh`  
;naD`([  
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/* >wiW(Ki}  
**Utility.java A %iZ_h^  
*/ 9%>GOY  
package NetFox; Nwu,:}T  
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public class Utility { 6Z:<?_p%7g  
1+1Z]!nG#!  
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public Utility() C NDf&dzX8  
{ [89qg+z  
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} !,f{I5/  
P&

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//线程睡眠 :x*|?zII  
public static void sleep(int nSecond) ^l}Esz`-M  
{ N=e-"8  
try{ dg9 DBn#  
Thread.sleep(nSecond); 8lAs~c  
} )/BI
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catch(Exception e) `N8?F3>
 
{ C-Q]f
 
e.printStackTrace (); a}~Xns  
} y8=(k}=3  
} NA5AR*f'  
B3Id}[V  
//日志 Xr54/.{&@  
public static void log(String sMsg) fAHK<G4  
{ @D<q=:k  
System.err.println(sMsg); mJBvhK9%  
} s68&AB  
%E\&9,  
AS;EO[Vn  
public static void log(int sMsg) 1&S34wJF  
{ 95Q{d'&  
System.err.println(sMsg); dac?b(  
} 8cqH0{  
} 3l?D%E]P  
7Sc._G{[%  
~f/nq/8  
/* cVHv>nd#  
**TestMethod.java =.q Zgcg  
*/ T~shJ0%  
package NetFox; ~&>|u5C*@  
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public class TestMethod { )sWC5\  
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public TestMethod() H
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{ ///xx/weblogic60b2_win.exe 'Xl[ y  
try{ ,L iX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >"^H"K/T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p~ `f.q$'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cVrses^yE  
fileFetch.start(); e0i&?m  
} y'ZRoakz)  
catch(Exception e){e.printStackTrace ();} u="VJ3
 
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} $ b Q4[  
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public static void main(String[] args) JTH8vk:@  
{ seT?:PCA  
new TestMethod(); B^W0Ik`m  
} 1aC?*,e?  
} J1
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