http断点续传简单实现（java)

/* Oc; G(l(  
**SiteFileFetch.java 1!gbTeVlY  
*/ ?F;8Pa/  
package NetFox; !v0LBe4  
import java.io.*; /FJu)H..U  
import java.net.*; })?GzblI&  
= 9]~yt  
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public class SiteFileFetch extends Thread { vZoaT|3 G]  

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SiteInfoBean siteInfoBean = null; //文件信息Bean 0K2`-mL  
long[] nStartPos; //开始位置 L,@lp  
long[] nEndPos; //结束位置 xZv#Es%#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?3xzd P  
long nFileLength; //文件长度 jalg5`PU0  
boolean bFirst = true; //是否第一次取文件 @|%2f@h  
boolean bStop = false; //停止标志 t`mV\)fa
 
File tmpFile; //文件下载的临时信息 Wiu"k%Qsh  
DataOutputStream output; //输出到文件的输出流 U`m54f@U  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
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public SiteFileFetch(SiteInfoBean bean) throws IOException _f:W?$\ho  
{ 3Ims6I]  
siteInfoBean = bean; # 4PVVu<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :[!j?)%>  
if(tmpFile.exists ()) ]P?vdgEM&  
{ C 6AUNRpl  
bFirst = false; Z/;aT -N  
read_nPos(); I(0~n,=j  
} iW /}#  
else 9p2&)kb6  
{ cjIh}:|'  
nStartPos = new long[bean.getNSplitter()]; {,~3.5u   
nEndPos = new long[bean.getNSplitter()]; /gkX38  
} igR";OQk  
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} fx>4  
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public void run() '(L7;+E  
{ r|Tcfk]%  
//获得文件长度 r? E)obE  
//分割文件 }@+:\   
//实例FileSplitterFetch "5wa91*  
//启动FileSplitterFetch线程 ?oHpFlj  
//等待子线程返回 c|@bwat4  
try{ Ge-vWf-RbB  
if(bFirst) Y\?"WGL)p  
{ -:y,N 9^  
nFileLength = getFileSize(); ByNn  
if(nFileLength == -1) JHTSUq  
{ Vt&2z)Zz  
System.err.println("File Length is not known!"); Y^EcQzLw  
} @8r pD"x  
else if(nFileLength == -2) Q:k}Jl  
{ Ks`J([(W&  
System.err.println("File is not access!"); iVq'r4S  
} PKg@[<g43  
else X
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{ {go;C}  
for(int i=0;i<nStartPos.length;i++) iN8zo:&Z  
{ lBvR+9Qw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xH"/1g  
} "8jf81V*  
for(int i=0;i<nEndPos.length-1;i++) 7/@TF/V  
{ A1>OY^p3%  
nEndPos = nStartPos[i+1]; 70tH:Z)"  
} WX|`1b  
nEndPos[nEndPos.length-1] = nFileLength; qwgPk9l  
} j0evq+  
} G[I"8iS,  
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//启动子线程 EC!02S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 62o:,IcoG  
for(int i=0;i<nStartPos.length;i++) .Una+Z  
{ 3E
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8ek@:
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W^LY'ypT  
nStartPos,nEndPos,i); ( !fKNia@S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :C
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fileSplitterFetch.start(); f=gW]x7'R+  
} .p]RKS=(:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k(7&N0V%zz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iYm-tsER;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ']z{{UNUN  
nEndPos = " + nFileLength); YdC6k?tzS  
// fileSplitterFetch[nPos.length-1].start(); rkCx{pe9  
4`]^@"{  
]i ,{  
//等待子线程结束 D_^ nI:  
//int count = 0; KD7dye  
//是否结束while循环 Tg)|or/%  
boolean breakWhile = false; O6a<`]F  
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while(!bStop) j8{i#;s!"  
{ qqr?!vem6  
write_nPos(); f:|1_j  
Utility.sleep(500); 6J6BF%  
breakWhile = true; J76kkW`5  
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{e9@-  
for(int i=0;i<nStartPos.length;i++) JZ*/,|1}EC  
{ ju8q?Nyhs  
if(!fileSplitterFetch.bDownOver) bj0G5dc=  
{ A_ N;   
breakWhile = false; 0c'<3@39k|  
break; KNpl:g3{<Q  
} yyRiP|hJ  
} Ln<`E|[29  
if(breakWhile) =eXU@B  
break; A) %/[GD2  
e
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//count++; [{<`o5qR  
//if(count>4) [-k  
// siteStop(); x_6[P2"PP  
} ?o4C;  
2%@4]  
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System.err.println("文件下载结束！"); wb5baY9  
} tip+q d  
catch(Exception e){e.printStackTrace ();} OSWYGnZg  
} zrL$]Oy}x  
w/S%YW3*  
[OV"}<V  
//获得文件长度 ," Wr"  
public long getFileSize() aa?b`[Xa  
{ H*&f:mfq  
int nFileLength = -1; }{qZ[/JwqN  
try{ k,E{C{^M  
URL url = new URL(siteInfoBean.getSSiteURL()); )=Z>#iH1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @6F#rz  
httpConnection.setRequestProperty("User-Agent","NetFox"); N~d?WD\^  
ceh j;  
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int responseCode=httpConnection.getResponseCode(); \y)rt )  
if(responseCode>=400) { MSkHf=  
{ '}JhzKNj  
processErrorCode(responseCode); lhz{1P]s  
return -2; //-2 represent access is error qL&[K>2z  
} E$:*NSXj  
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String sHeader; O=&0H|B  
m!4ndO;0vh  
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for(int i=1;;i++) )}]g] g  
{ S)k*?dQ##R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~xfP:[u  
//Utility.log(in.readLine()); 7he,?T)vD  
sHeader=httpConnection.getHeaderFieldKey(i); T`.O'!  
if(sHeader!=null) Lh"<XYY  
{ f/NH:1)y  
if(sHeader.equals("Content-Length")) iNz=e=+Si  
{ 3n1;G8Nf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]Svt`0|}  
break; 1N^[.=  
} ^f &XQQY  
} ICoHI  
else .hP D$o  
break; ARVf[BAJ-*  
} 2d(e:rh]  
} wd^':  
catch(IOException e){e.printStackTrace ();} ;%5N%
0,  
catch(Exception e){e.printStackTrace ();} YTpSHp
f@  
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Utility.log(nFileLength); ;|5F[  
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return nFileLength; Eh;'S"{/?j  
} # E^1|:  
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//保存下载信息（文件指针位置） }6}l7x  
private void write_nPos() E7Ul;d  
{ '&R2U_  
try{ @=Uh',F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i2A8
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output.writeInt(nStartPos.length); A*R^n}sh  
for(int i=0;i<nStartPos.length;i++) |y# Jx  
{ *74MWF@IY  
// output.writeLong(nPos); }wjw:M  
output.writeLong(fileSplitterFetch.nStartPos); Mzw<{*:r  
output.writeLong(fileSplitterFetch.nEndPos); cAqLE\h  
} |&nS|2.'  
output.close(); qIE9$7*X  
} [nG<[<0G;  
catch(IOException e){e.printStackTrace ();} <8i//HOE  
catch(Exception e){e.printStackTrace ();} '8.r-`l(  
} B+VubUPMS  
<X^
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4 Y9`IgQ  
//读取保存的下载信息（文件指针位置） #u
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private void read_nPos() ]G=L=D^cK  
{ UWJ8amA  
try{ J+DDh=%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); V`d,qn)i  
int nCount = input.readInt(); 6NuD4Ga  
nStartPos = new long[nCount]; S_4?K)n #  
nEndPos = new long[nCount]; K.nHii   
for(int i=0;i<nStartPos.length;i++) (sTpmQx,b  
{ Y>T-af49  
nStartPos = input.readLong(); 8f4b&ah  
nEndPos = input.readLong(); 4Zddw0|2  
} LTCb@L{^i  
input.close(); ~&_z2|UXp  
} T_ <@..C  
catch(IOException e){e.printStackTrace ();} JCzeXNY  
catch(Exception e){e.printStackTrace ();} SC!RbW@3  
} ]e^&aR5f"  
Jk11fn;\>  
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private void processErrorCode(int nErrorCode) G1tY)_-8[  
{ rjAn@!|:+  
System.err.println("Error Code : " + nErrorCode); r:'.nhe  
} t?&|8SId  
\gGW8Q;  
Z'W=\rl  
//停止文件下载 KVaiugQ  
public void siteStop() [z\$?VJspQ  
{ 2'\H\|  
bStop = true; zO
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for(int i=0;i<nStartPos.length;i++) ^4hO  
fileSplitterFetch.splitterStop(); 1~`fVg  
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} {.|CdqwY  
} I@~QV@U  
//负责部分文件的抓取 v`x.)S1  
**FileSplitterFetch.java Tc:)- z[o  
*/ @4#c&h3  
package NetFox; ({)+3]x  
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import java.io.*; cn3\k
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import java.net.*; su(1<S}  
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public class FileSplitterFetch extends Thread { 1D7`YKI9h  
[Ek7b*  
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String sURL; //File URL aCj&O:]=  
long nStartPos; //File Snippet Start Position :#ik. D  
long nEndPos; //File Snippet End Position ^|>PA:%  
int nThreadID; //Thread's ID ,HV(l+k {|  
boolean bDownOver = false; //Downing is over 5` ~JPt  
boolean bStop = false; //Stop identical YnMvl  
FileAccessI fileAccessI = null; //File Access interface RJ&RTo  
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ncdKj}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (OL4Ex']  
{ NB#OCH1/9  
this.sURL = sURL; pRpBhm;iJ  
this.nStartPos = nStart; wo/\]5  
this.nEndPos = nEnd; [kB7@o  
nThreadID = id; !hy-L_wL]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Lv7(st%`  
} 3M7/?TMw{6  
QO~P7r|A  
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public void run() 2- h{N  
{ q:0N<$63  
while(nStartPos < nEndPos && !bStop) 783,s_  
{ >T-u~i$s  
*n ]GsOOn  
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try{ aFm_;\  
URL url = new URL(sURL); &`
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m?}6)\ob  
httpConnection.setRequestProperty("User-Agent","NetFox"); p27~>xQ  
String sProperty = "bytes="+nStartPos+"-"; P|E| $)m  
httpConnection.setRequestProperty("RANGE",sProperty); 8q!]y6  
Utility.log(sProperty); 1(R}tRR7R  
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InputStream input = httpConnection.getInputStream(); _6hQ %hv8  
//logResponseHead(httpConnection); Gj?t_Zln  
'GWN~5  
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byte[] b = new byte[1024]; .!3|&V'<  
int nRead; ,/2Vt/lt  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RSRS wkC  
{ {\1?ZrCI&  
nStartPos += fileAccessI.write(b,0,nRead); \?-<4Bc@  
//if(nThreadID == 1) !>o7a}?
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J!(<y(l  
} G>}255qY  
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AV]2euyn  
Utility.log("Thread " + nThreadID + " is over!"); my1@41 H  
bDownOver = true; JyK3{wYS  
//nPos = fileAccessI.write (b,0,nRead); *:7rdzn  
} cqkV9f8Ro  
catch(Exception e){e.printStackTrace ();} V2EUW!gn 2  
} !9e=_mY  
} ~G&dqw/.-U  
`
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%aCqi(.7  
//打印回应的头信息 ^z*t%<@[Q  
public void logResponseHead(HttpURLConnection con) Wvh#:Z  
{ _4~+{l+  
for(int i=1;;i++) Q3~H{)[Kq  
{ Nh|uO?&C6  
String header=con.getHeaderFieldKey(i); ; DR$iH-F  
if(header!=null) t{9GVLZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0Mm)`!TLSW  
Utility.log(header+" : "+con.getHeaderField(header)); eo?bL$A[s  
else oZgjQM$YP  
break; _jVN&\A]mC  
} ^{`exCwMx  
} q.bSIV|  
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5C]x!>kX  
public void splitterStop() M|h3Wt~7  
{ TIDO@NwF  
bStop = true; (ZZ8L-s  
} hn@08t G  
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KV *#T20T  
} .`eN8Dl1  
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T!#GW/?  
/* + &Eqk  
**FileAccess.java YD6'#(  
*//文件访问(定位，写) (w3YvG.  
package NetFox; X+9>A.92  
import java.io.*; ZLejcYS  
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public class FileAccessI implements Serializable{ C&%_a~  
{VRf0c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CHX#^0m.  
RandomAccessFile oSavedFile; H7n>Vx:L-  
long nPos; 0{D'n@veP  
va@Lz&sAE%  
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public FileAccessI() throws IOException r#a=@  
{ oG\Vxg*  
this("",0); SqpaFWr  
} a;+9mDXx:  
8nV+e~-w  
"!^
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public FileAccessI(String sName,long nPos) throws IOException CA~-rv  
{ q<1~ vA9  
oSavedFile = new RandomAccessFile(sName,"rw"); R-$!9mnr  
this.nPos = nPos; _Fl9>C"u  
oSavedFile.seek(nPos); U[MA)41  
} )ez9"# MH'  
99QU3c<.  
3=j"=-=  
public synchronized int write(byte[] b,int nStart,int nLen) PJH&  
{ rV#ch(  
int n = -1; /U9"wvg  
try{ f]CXu3w(J  
oSavedFile.write(b,nStart,nLen); VTE .^EK!  
n = nLen; ;e*!S}C,  
} 7!E,V:bt'  
catch(IOException e) } q8ASYNc  
{ zrb}_  
e.printStackTrace (); Q![@c  
} 8d'0N  
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return n; 26h21Z16q  
} t{{QE:/  
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} I!K6o.|1  
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/* x.$FNt(9  
**SiteInfoBean.java s$j,9uRr  
*/ tR$NRMZ.  
package NetFox; P&Vv/D  
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.  
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public class SiteInfoBean { j3Y['xDv  
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private String sSiteURL; //Site's URL cr;da)  
private String sFilePath; //Saved File's Path tCt#%7J;a  
private String sFileName; //Saved File's Name eaU  
private int nSplitter; //Count of Splited Downloading File Nh44]*  
?:0Jav  
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public SiteInfoBean() BI@[\aRLQ  
{//nSplitter的缺省值为5 S_H+WfIHV'  
//default value of nSplitter is 5 dR]m8mdqc1  
this("","","",5); pQB."[n  
} y6BAH  
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]`WJOx4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Mi_$">1-W  
{ )^hbsMhO  
sSiteURL= sURL; ?S=mybp  
sFilePath = sPath; JBZ@'8eqi]  
sFileName = sName; WcGS9`m/  
this.nSplitter = nSpiltter; _+MJ%'>S
 
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} HGg@ _9tW  
+=)+'q]S  
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public String getSSiteURL() >9J:Uo1z  
{ Tlr v={  
return sSiteURL; uB?ZcF}Tk  
} .=; ;  
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public void setSSiteURL(String value) dj%!I:Q>u  
{ W2!+z{:m  
sSiteURL = value; A3*!"3nU  
} X@F
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public String getSFilePath() 5!9zI+S|=`  
{ Flb&B1  
return sFilePath; xgtR6E^k  
} EoDA]6?Lj  
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O#r%>;3*  
public void setSFilePath(String value) &)<)^.@3G^  
{ sDV Q#}a  
sFilePath = value; V(*
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} cB&:z)i4  
zbPqYhJzA  
2:ylv<\$  
public String getSFileName() \73ch  
{ apxph2yvS  
return sFileName;  9gZ$
 
} `r_/Wt{g  
)!T/3|C  
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public void setSFileName(String value) >(RkZ}z  
{ jc9y<{~x/  
sFileName = value; 6W UrQFK  
} .N(p=9  
bZV
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public int getNSplitter() *{{89E>wC  
{ U/BR*Zn]*  
return nSplitter; :M5l*sIO2  
} zx7{U8*`<  
Y <qm{e  
9_s`{(0?  
public void setNSplitter(int nCount) ?bu>r=oIO]  
{ F6dP,(  
nSplitter = nCount; :Ux_qB  
} HpnWoDM  
} 8~gLqh8^V  
"zy7C*)>r  
I<tm"?q0  
/* 8\gjST*  
**Utility.java v.5+7,4  
*/ )dSi/  
package NetFox; 4X|zmr:A  
xN%K^Tree  
~PNub E  
public class Utility { W@!S%Y9  
;9g2?-svw  
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public Utility() 4E?Oky#}-  
{ 3f;>" P}  
S21,VpW\  
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} POR\e|hRT]  
VLN_w$iEq  
//线程睡眠 !{41!O,K#  
public static void sleep(int nSecond)
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{ >lM l  
try{ &jr3B;g!C  
Thread.sleep(nSecond); & ZB  
} E1f\%!2l  
catch(Exception e) 2GStN74Xr  
{ 4xJQ!>6  
e.printStackTrace (); =mmWl9'mJ  
} @xZR9Z8]L  
} RCLeA=/N@0  
4v|W-h"K  
//日志 u>/ TE  
public static void log(String sMsg) 61 ~upQaR  
{ g$o&Udgs  
System.err.println(sMsg); BL58] P84  
} xAP+FWyV  
(_{yB[z>`  
'[O;zJN;  
public static void log(int sMsg) y18Y:)DkL  
{ Pr,q*_Yy  
System.err.println(sMsg); P L+sR3bR  
} s&J]zb`  
} R_xRp&5  
/|#fejPh  
t);/'3|  
/* Vs{|xG7WD  
**TestMethod.java e(8Ba X_  
*/ /JU.?M35  
package NetFox; Oz#{S:24M+  
o,3a4nH;  
8sK9G` k  
public class TestMethod { uA#;G/$  
{cw /!B  
q6X1P"%.  
public TestMethod() $xdy&  
{ ///xx/weblogic60b2_win.exe eQvg7aO;  
try{ w:l V"]1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?@ $r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `pZm?}K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [;sRV<  
fileFetch.start(); HiJE}V;Vq  
} $7A8/#  
catch(Exception e){e.printStackTrace ();} 7i1q wRv  
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S`m]f5u|  
} BJo*'US-Q  
mU9kVx1+  
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public static void main(String[] args) jOD?|tK&  
{ ib791  
new TestMethod(); _2 osV[e  
} N=g"(%  
} SOvF[,+  
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