http断点续传简单实现（java)

/* b!-F!Lq/+0  
**SiteFileFetch.java o;Ma)/P  
*/ 1W2hd!J7C  
package NetFox; q6 Rr?  
import java.io.*; 0hx EI  
import java.net.*; ni
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public class SiteFileFetch extends Thread { FrBJv<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `}9jvR5  
long[] nStartPos; //开始位置 h\qM5Qx+Q  
long[] nEndPos; //结束位置 SPK% '
s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W"L;8u  
long nFileLength; //文件长度 ,~,{$\p   
boolean bFirst = true; //是否第一次取文件 (#;<iu}  
boolean bStop = false; //停止标志 $j!VJGVG  
File tmpFile; //文件下载的临时信息 _3?7iH  
DataOutputStream output; //输出到文件的输出流 6H_7M(f  
8'X:}O/  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [>tyx{T Ye  
public SiteFileFetch(SiteInfoBean bean) throws IOException D%k]D/  
{ Z39I*-6F9W  
siteInfoBean = bean; ]@MBE1M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C 9:5c@G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e^ygQ<6%  
if(tmpFile.exists ()) s9-aPcA  
{ F)g.xQ  
bFirst = false; 92HxZ*t7km  
read_nPos(); d;10[8:5=  
} R@)L@M)u;  
else Vr=c06a2  
{ U[ $A=e?\Y  
nStartPos = new long[bean.getNSplitter()]; N [iv.B  
nEndPos = new long[bean.getNSplitter()]; ,
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} qhiO( !jK  
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} =5sUpPV(  
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public void run() d;D8$q)8
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{ h (`Erb  
//获得文件长度 pK~K>8\  
//分割文件 |P"p/iY  
//实例FileSplitterFetch z"C+r'39d=  
//启动FileSplitterFetch线程 S4?N_"
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//等待子线程返回 s*U~Q=Z  
try{ ua]>0\D  
if(bFirst) !wttKUO?  
{ ;w_f^R #  
nFileLength = getFileSize(); eQUm!9)  
if(nFileLength == -1) *[eh0$  
{ ,mE*k79L6  
System.err.println("File Length is not known!"); P`K?k<  
} &91U(Go  
else if(nFileLength == -2) k*8 ld-O  
{ HjO-6F#s  
System.err.println("File is not access!"); u~9gR@e2{  
} {)QSxO  
else *MEDV1l_T  
{ n"
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for(int i=0;i<nStartPos.length;i++) z5G$'  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); *y;(c)_w/%  
} Nuw_,-h  
for(int i=0;i<nEndPos.length-1;i++) Y4 Y;xK"  
{ :u7y k@  
nEndPos = nStartPos[i+1]; uZ-yu|1  
} 6-@ X  
nEndPos[nEndPos.length-1] = nFileLength; Y!6,ty'  
} ]~SOGAFW  
} m};Qng]  
*@|EaH/  
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//启动子线程 OI9V'W$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q>T7};5m2  
for(int i=0;i<nStartPos.length;i++) Ifm|_  
{ 8tM40/U$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DJv;ed%x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `&"-|  
nStartPos,nEndPos,i); :Qg3B ';  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); APgP*,  
fileSplitterFetch.start(); qn+b
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} <xm>_~,w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tnbtfG;z#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z#8d\X/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  ;Q;u^T`  
nEndPos = " + nFileLength); Q-X<zn  
// fileSplitterFetch[nPos.length-1].start(); S1<mO-  
 lqO"  
{o?+T);Z  
//等待子线程结束 Khbkv  
//int count = 0; ab1qcQ<  
//是否结束while循环 \k{UqU+s  
boolean breakWhile = false; e>Vr#a4  
2[W1EQI  
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while(!bStop) Ri@`sc{n  
{ G &'eP  
write_nPos();
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Utility.sleep(500); Mb6#97  
breakWhile = true; yB&+2  
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for(int i=0;i<nStartPos.length;i++) R0R
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{ w !N;Y0  
if(!fileSplitterFetch.bDownOver) Xj/U~  
{ u;xl}  
breakWhile = false; xhAORhw#  
break; \4RVJ[2  
} qV%t[>  
} #OKzJ"g
 
if(breakWhile) I<q=lK  
break; *RQkL'tRf  
"JLKO${ Y  
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//count++; { jnQoxN  
//if(count>4) *^XfEO  
// siteStop(); "x.|'  
} LLn,pI2fL{  
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System.err.println("文件下载结束！"); !$"DD[~\  
} `.f {V  
catch(Exception e){e.printStackTrace ();} |fMjg'%{}  
} c5K@<=?,E  
=_%i5]89P  
8]6u]3q#  
//获得文件长度 Z&hzsJK{m$  
public long getFileSize() V0Cz!YM_3  
{ b_&;i4[  
int nFileLength = -1; o#KGEN
d  
try{ /P~@__XN  
URL url = new URL(siteInfoBean.getSSiteURL()); sN^3bfi!i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &+?JY|u  
httpConnection.setRequestProperty("User-Agent","NetFox"); @(Mg>.P  
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int responseCode=httpConnection.getResponseCode(); ,~ D_T  
if(responseCode>=400) 6N}>@Y5  
{ `mro2A  
processErrorCode(responseCode); 8Z TN  
return -2; //-2 represent access is error 2\flTO2Ny  
} ;\@co5.=  
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String sHeader; =9UR~-`d\  
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for(int i=1;;i++) ;-=Q6Ms8  
{ vc.:du  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -2}-;|  
//Utility.log(in.readLine()); '-sAi  
sHeader=httpConnection.getHeaderFieldKey(i); En:.U9?X  
if(sHeader!=null) bkQEfx.  
{ Vy;f4;I{  
if(sHeader.equals("Content-Length")) <MgR x9  
{ NZ(c>r6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MS~c  $  
break; C9-IJj  
} \{F{yq(  
} MTZbRi6z  
else tAfd
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break; ]UG+<V ,:  
} 8r^~`rL  
} $d1+d;Mn  
catch(IOException e){e.printStackTrace ();} jseyT#2  
catch(Exception e){e.printStackTrace ();} ! 6kLL  
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Utility.log(nFileLength); V`OeJVe  
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return nFileLength; !xs.[&u8  
} +8e~jf3E1  
| ,bCYK  
si.A"\bm  
//保存下载信息（文件指针位置） i)nb^  
private void write_nPos() 3,~M`~B  
{ Si,[7um  
try{ N zY}-:{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I^iJ^Z]vx  
output.writeInt(nStartPos.length); F+A"-k_\T#  
for(int i=0;i<nStartPos.length;i++) 7Y$#* 7  
{
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// output.writeLong(nPos); D9H(kk  
output.writeLong(fileSplitterFetch.nStartPos); {R[FwB^7wJ  
output.writeLong(fileSplitterFetch.nEndPos); F|K=].  
} rn^7B-V  
output.close(); O>)<w Ms`  
} 2s,[DC  
catch(IOException e){e.printStackTrace ();} Bl5*sfjG  
catch(Exception e){e.printStackTrace ();} J/3qJst
 
} ZMmaM "9  
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//读取保存的下载信息（文件指针位置） t^0^He$Ot  
private void read_nPos() e)dPv:oK3  
{ l4+!H\2  
try{ NET?Ep  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JcsJfTI  
int nCount = input.readInt(); (lwrk(  
nStartPos = new long[nCount]; <rUH\z5cP  
nEndPos = new long[nCount]; QUL^]6$  
for(int i=0;i<nStartPos.length;i++) @OOnO+g  
{ 7n*,L5%?]4  
nStartPos = input.readLong(); 9-;ujl?{  
nEndPos = input.readLong(); R<VNbm;  
} -.A%c(|Q  
input.close(); .Ap-<FB  
} 'P{0K?{H-4  
catch(IOException e){e.printStackTrace ();} Fw!wSzsk3  
catch(Exception e){e.printStackTrace ();} Qmxe*@{`  
} 70,V>=aJ  
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private void processErrorCode(int nErrorCode) :34#z.O  
{ ;seD{y7!  
System.err.println("Error Code : " + nErrorCode); %4#,y(dO  
} rj[2XIO  
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//停止文件下载 Js7(TFQE  
public void siteStop() " , c1z\  
{ >r%L=22+  
bStop = true; #:0dqD=  
for(int i=0;i<nStartPos.length;i++) UW7*,Bq  
fileSplitterFetch.splitterStop(); 5Hvg%g-c  
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} z-|gw.y  
} pKDP1S#<  
//负责部分文件的抓取 8Xpf|?.  
**FileSplitterFetch.java K8NoY6  
*/ u"IYAyzL  
package NetFox; j.Ro(0%  
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d (Ufj|;  
import java.io.*; 85; BS'  
import java.net.*; ' uvTOgP,  
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public class FileSplitterFetch extends Thread { Wz)O,X^  
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String sURL; //File URL cW B>  
long nStartPos; //File Snippet Start Position $0WO 4C%M  
long nEndPos; //File Snippet End Position ~>C@n'\lv  
int nThreadID; //Thread's ID YbaaX{7^  
boolean bDownOver = false; //Downing is over V<X[>C'  
boolean bStop = false; //Stop identical l-;u*JA  
FileAccessI fileAccessI = null; //File Access interface eqvbDva^  
8MIn~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WXJEAje  
{ Lhg4fuos@)  
this.sURL = sURL; ckR>ps[u  
this.nStartPos = nStart; L$R"?O7  
this.nEndPos = nEnd; { +d](+$  
nThreadID = id; +NIq}fZn9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cd_\?7  
} JbT+w\o  
#2*l"3.$.R  
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public void run() CPJ8G}4  
{ 9a\H+Y~  
while(nStartPos < nEndPos && !bStop) Ziclw)   
{ ;bz|)[4/  
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try{ f3,qDbQyJ  
URL url = new URL(sURL); >
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m|K"I3W$  
httpConnection.setRequestProperty("User-Agent","NetFox"); X[' VZz7  
String sProperty = "bytes="+nStartPos+"-"; |.w'Z7(s  
httpConnection.setRequestProperty("RANGE",sProperty); _+c' z  
Utility.log(sProperty); Be~__pd  
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InputStream input = httpConnection.getInputStream(); 2~`lvx  
//logResponseHead(httpConnection); @9,=|kxK  
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byte[] b = new byte[1024]; %S$P<nKN5  
int nRead; isU7nlc!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PE!/n6  
{ U;SReWqU  
nStartPos += fileAccessI.write(b,0,nRead); 0L->e(Vf7u  
//if(nThreadID == 1) 8 $5 y]%!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #&v86  
} F4M )x`  
zN3[W`q+m  
e"=/zZH3  
Utility.log("Thread " + nThreadID + " is over!"); b/#SkxW#S  
bDownOver = true; \
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//nPos = fileAccessI.write (b,0,nRead); @;\2 PD  
} .AB n$ml]  
catch(Exception e){e.printStackTrace ();} 8'K~+L=}  
} TJYup%q  
} rcq^mPdQ  
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//打印回应的头信息 '=s{9lxn^  
public void logResponseHead(HttpURLConnection con) ^)J2tpr;]=  
{ d_v]mfUF  
for(int i=1;;i++) ko-3`hX`  
{ [j3-a4Wu  
String header=con.getHeaderFieldKey(i);
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if(header!=null) e0s*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ! qVuhad.  
Utility.log(header+" : "+con.getHeaderField(header)); C8{bqmlm@  
else  3o_)x  
break; _\/KI /  
} mS$9D{  
} [zC1LTXe  
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public void splitterStop() 9f(0 qa  
{
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bStop = true; +N6IdDN3  
} `}r)0,Z}3  
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} pwF+ZNo  
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/EIQMZuYp  
/* Ob~7w[n3  
**FileAccess.java ]QU 9|1  
*//文件访问(定位，写) saRYd{%+  
package NetFox; f 7R
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import java.io.*; hQeGr2gMq  
xNrPj8V<Y  
lQS(\}N  
public class FileAccessI implements Serializable{ !Y8+Z&^2  
GyC/39<P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F_U9;*f]  
RandomAccessFile oSavedFile; IZ/PZ"n_(  
long nPos; Gye84C2E=  
|2Vhj<6  
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public FileAccessI() throws IOException 9T\uOaC"  
{ m&PB5s\=  
this("",0); P,Z K  
} %K`th&331  
bIWSNNV0F  
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public FileAccessI(String sName,long nPos) throws IOException bcR";cE  
{ adcH3rV  
oSavedFile = new RandomAccessFile(sName,"rw"); A`B>fI  
this.nPos = nPos; UF&B7r  
oSavedFile.seek(nPos); ~|lEi1|  
} @3w6!Sgh  
*b}/fG)XZ  
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public synchronized int write(byte[] b,int nStart,int nLen) U#iGR5&^3  
{ &ir|2"HV  
int n = -1; +`J~c|(  
try{ [+F6C  
oSavedFile.write(b,nStart,nLen); ptc.JB6  
n = nLen; } =
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} n#l~B
@  
catch(IOException e) Bq5-L}z  
{ /n2qW.qJ>  
e.printStackTrace (); n2(`O^yd7C  
} ]')  
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return n; .GSK!
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} q)l1tC72  
eP|_  
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} 4wkmgS  
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/* uv&4 A,h  
**SiteInfoBean.java c(kYCVc   
*/ 8 7z]qE  
package NetFox; b}3t8?wG&  
"C.cU  
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public class SiteInfoBean { dHkI9;  
.MS41 E!  
=o)B1(v@.  
private String sSiteURL; //Site's URL Gc=uKQ+\V  
private String sFilePath; //Saved File's Path o?g9Grk  
private String sFileName; //Saved File's Name TFNB%|  
private int nSplitter; //Count of Splited Downloading File Hmx Y{KB  
wpI"kk_@@  
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public SiteInfoBean() S^x?<kYQau  
{//nSplitter的缺省值为5 *=}\cw\A  
//default value of nSplitter is 5 nK)hv95i_  
this("","","",5); JA$RY  
} S-[S?&c`  
lt("yqBu
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nh]HEG0CZJ  
{ eMLcmZJR  
sSiteURL= sURL; >|pN4FS  
sFilePath = sPath; a0jzt!ci  
sFileName = sName; ydTd.`  
this.nSplitter = nSpiltter; Sc?q}tt^C  
aF{1V\e  
sE])EwZ  
} 1d!TU=*  
6VtN4c.Q  
]-sgzM]q  
public String getSSiteURL() ^&lkh@Y1q  
{ eUKl(  
return sSiteURL; 3>6rO4,  
} FOAXm4"  
4$y P_3  
Yy{(XBJ~%t  
public void setSSiteURL(String value) I_Omv{&u  
{ gh-i|i,  
sSiteURL = value; Ltk-1zhI  
} hs*n?vxp3  

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I uC7Hx`z  
public String getSFilePath() cR=o!2O  
{ tZY6{,K%4  
return sFilePath; ;YZ'd"0v  
} )~CNh5z6Y  
& h\!#X0  
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public void setSFilePath(String value) K8W99:v  
{ LMNmG]#!  
sFilePath = value; PVSz%"
 
} t[ZGY,8  
6!C>J#T  
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public String getSFileName() #fDM{f0]R  
{ B%WkM\\!^  
return sFileName; lf\^!E:  
} q8}he~a  
NcX`*18  
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public void setSFileName(String value) .;)V;!   
{ IN,=v+A  
sFileName = value; 9w6 uoM  
} (K('@W%\?  
/z)Nz2W  
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public int getNSplitter() CY\D.Eow  
{ Mzw:c#  
return nSplitter; {mB!mbr  
} dwouw*8  
VHG}'r9KC%  
A@eR~Kp ^  
public void setNSplitter(int nCount) 30O7u3Zrb  
{ *6G@8TIh  
nSplitter = nCount; "|BSGV!8  
} x->+wJm@s  
} }tQ^ch;Q  
_:%i6c*"  
]
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/* }lP`3e  
**Utility.java _Nh`-R%B)  
*/ iqFC~].)  
package NetFox; KV! (   
rN,T}M=2  
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public class Utility { <`
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public Utility() 0]zMb^wo  
{ +p$lVnAt  
SX&Q5:  
eCiI=HcW;  
} J06D_'{  
yG;@S8zC  
//线程睡眠 I]%Kd('  
public static void sleep(int nSecond) 0es\ j6c  
{ j9X|c7|  
try{ vnS8N  
Thread.sleep(nSecond); h@TP=  
} :sttGXQX  
catch(Exception e) q0b*#j  
{ DPkH:X  
e.printStackTrace (); ,b:~
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} ">5$;{;2r  
} {w@9\LsU  
=ui3I_*)  
//日志 9ji`.&#  
public static void log(String sMsg) =mSu^q(l  
{ F:~@e(  
System.err.println(sMsg); ay#f\P!1  
} =2YXh,i  
:? s{@7  
Y ` Z,52  
public static void log(int sMsg) L#%)@  
{ q7I!wD9Cff  
System.err.println(sMsg); 7G
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} yb>R(y  
} ]<K"`q2  
~[f`oC  
hZw8*H^tP  
/* }Syd*%BR[  
**TestMethod.java IZGRQmi"  
*/ //RD$e?h~  
package NetFox; t*)!BZ  
y.-Kqa~  
=MvB9gx@r  
public class TestMethod { "xnULQK  
Xkk 8#Y
":  
E^0a; |B[  
public TestMethod() =\mJ5v"hA  
{ ///xx/weblogic60b2_win.exe TM|PwY  
try{ %m|1LI(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xo2jfz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i5|)|x3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $<"I*l@  
fileFetch.start(); 0M?zotv0#  
} yE~D0%Umq  
catch(Exception e){e.printStackTrace ();} F%.UpV,  
64vj6 &L  
Ktu~%)k%  
} nPDoK!r'  
-<sW`HpD'  
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public static void main(String[] args) SbQ:vAE*ho  
{ V(g5Gn
?  
new TestMethod(); `5"3Cj"M  
} drvrj~o:  
} m4yWhUi(o  
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