http断点续传简单实现（java)

/* Vc "+|^  
**SiteFileFetch.java L>,xG.oG  
*/ e`%<D[-  
package NetFox; l/bZE.GJ  
import java.io.*; kfy|3KA3m  
import java.net.*; .c_qMTm"  
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public class SiteFileFetch extends Thread { ;x4yidb6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Qh4Z{c@  
long[] nStartPos; //开始位置 ]U5/!e  
long[] nEndPos; //结束位置 WD#7Q&T(;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v?S3G-r  
long nFileLength; //文件长度 {7 nz:f  
boolean bFirst = true; //是否第一次取文件 2;YL+v2  
boolean bStop = false; //停止标志 ] U[4r9V  
File tmpFile; //文件下载的临时信息 oo!JAv}~  
DataOutputStream output; //输出到文件的输出流 }zHG]k,j  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BE," lX  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2r#W#z%vS  
{ <VmEXJIk  
siteInfoBean = bean; `
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]Hrw$\Ky  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?uqPye1fc  
if(tmpFile.exists ()) o1u?H4z  
{
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bFirst = false; O@,9a~Ghd  
read_nPos(); IsB=G-s  
} );ZxKGjc4  
else i  M!=/  
{ MH_3nN  
nStartPos = new long[bean.getNSplitter()]; Bfr$&?j#  
nEndPos = new long[bean.getNSplitter()]; g}*F"k4j  
} qbQH1<yS<  
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} Z`kI6  
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public void run() %weG}gCM  
{ =BBDh`$R  
//获得文件长度  8=j_~&*  
//分割文件 R}\n@X*  
//实例FileSplitterFetch z4*`K4W  
//启动FileSplitterFetch线程
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//等待子线程返回 4'0rgS  
try{ EnXTL]=0S  
if(bFirst) X##hSGQM  
{ *W=R:Bl!  
nFileLength = getFileSize(); _.3O(?p,  
if(nFileLength == -1) 5KwT(R o  
{ %8T"h  
System.err.println("File Length is not known!"); !Ytr4DtM  
} +[$ Q C*  
else if(nFileLength == -2) nL&[R}@W  
{ wm_o(Z}  
System.err.println("File is not access!"); dzyp:\&9  
} @(LEuYq}  
else 8hm|9  
{ 5j-?Uf  
for(int i=0;i<nStartPos.length;i++) 0^&-j.9  
{  #Up X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5<L+T  
} <LA!L  
for(int i=0;i<nEndPos.length-1;i++) 2$gOe^ &  
{ eEMU,zCl  
nEndPos = nStartPos[i+1]; [f\TnXq24  
} =9#cf-?  
nEndPos[nEndPos.length-1] = nFileLength; R(N5K4J  
} X2hyxTOp  
} fkK42*U@r  
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//启动子线程 YCEdt>5PA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (uskVK>L  
for(int i=0;i<nStartPos.length;i++) @If ^5s;z  
{ Y+UM>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SFx|9$hXm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )%]`uj>*[  
nStartPos,nEndPos,i); ;]xJC j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ) v^;"q"  
fileSplitterFetch.start(); qx<h rC0Z&  
} \*k}RKDwT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eNw9"X}g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @XFy^?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b6A]/290x  
nEndPos = " + nFileLength); *&lNzz5&  
// fileSplitterFetch[nPos.length-1].start(); [`Dv#  
.3yxg}E>{  
;33LuD<h.  
//等待子线程结束 Q,z^eMk'd:  
//int count = 0; >@9>bI+Q  
//是否结束while循环 0NMekVi
 
boolean breakWhile = false; x7l3&;yDv  
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while(!bStop) RkuPMs Hw;  
{ h#!u"'JW  
write_nPos(); E;Sb e9]   
Utility.sleep(500); l d4#jV ei  
breakWhile = true; -<Zs7(  
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for(int i=0;i<nStartPos.length;i++) R#UcwX}o  
{ }tRY,f  
if(!fileSplitterFetch.bDownOver) S.X*)CBB  
{ z}:|is)?  
breakWhile = false; Z:(yX0U,[  
break; m}dO\;  
} 8Qt'Y9|  
} cy-Bhk0H  
if(breakWhile) 1"5-doo  
break; R"`7aa6  
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//count++; lYq4f|5H}m  
//if(count>4) s9'lw'  
// siteStop(); }+4^ZbX+:  
} <Fa]k'<^)  
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System.err.println("文件下载结束！"); %t:pG}A>:C  
} \KJ\>2Y  
catch(Exception e){e.printStackTrace ();} 3A(sT}  
} }+1Y>W7q  
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{Bb:S"7NX  
//获得文件长度 s]z-d!G  
public long getFileSize() SsE8;IGH  
{ "Wz#<! .r  
int nFileLength = -1; . w_oWmD  
try{ }+fMYgw  
URL url = new URL(siteInfoBean.getSSiteURL()); R|Lr@k{6+r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *>a+`|[1*  
httpConnection.setRequestProperty("User-Agent","NetFox"); [spJ%AhV  
L| uoFG{  
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int responseCode=httpConnection.getResponseCode(); dE[nPtstb  
if(responseCode>=400) &eHhj9  
{ |_^A$Hv  
processErrorCode(responseCode); I*Q^$YnM  
return -2; //-2 represent access is error _z$lg]q  
} sm~{fg  
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String sHeader; `Y~EL?
 
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for(int i=1;;i++) v0yaFP#kG  
{ Uz`K#Bz   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NBUSr}8|  
//Utility.log(in.readLine()); CAhkv0?8  
sHeader=httpConnection.getHeaderFieldKey(i); Gw5j6  
if(sHeader!=null) i,Q{Z@,  
{ ymxYE#q  
if(sHeader.equals("Content-Length")) >K2Md*[P3q  
{ Q8kdX6NMd&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^gK8 u]>  
break; Wp[R$/uT  
} &Q85Bq  
} UE[5Bw?4X  
else qx$-% P  
break; ]H4T80wm&  
} 0~5'O[NhF  
} < c}cgD4  
catch(IOException e){e.printStackTrace ();} v&NC` dVR  
catch(Exception e){e.printStackTrace ();} >(} I7  
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Utility.log(nFileLength); 9,4Lb]  
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return nFileLength; c<`Z[EY(t  
} ecoi4f  
i+2fWi6Z+  
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//保存下载信息（文件指针位置） sMq*X^z )?  
private void write_nPos() ;!JI$_-\  
{ ~e,D`Lv  
try{ i9qn_/<c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BixKK$Lo  
output.writeInt(nStartPos.length); &3SQVOW ~T  
for(int i=0;i<nStartPos.length;i++) )L*6xTa~  
{ {PXN$p:'  
// output.writeLong(nPos); /a?*Ap5"  
output.writeLong(fileSplitterFetch.nStartPos); l 4zl|6%  
output.writeLong(fileSplitterFetch.nEndPos); c3X'Sv  
} L@"1d.k_  
output.close(); 0<8pG:BQ  
} ZZ<uiN$  
catch(IOException e){e.printStackTrace ();} 5w\>Whbd  
catch(Exception e){e.printStackTrace ();} LG0z|x(  
} [84f[`!Ui  
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//读取保存的下载信息（文件指针位置） x2|YrkGv  
private void read_nPos() :3z`+5Y*  
{ S+mZ.aFS0z  
try{ ~i4h
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1mLd_]F'F  
int nCount = input.readInt(); cH&-/|N  
nStartPos = new long[nCount]; F ;o ^.  
nEndPos = new long[nCount]; z"b}V01F#  
for(int i=0;i<nStartPos.length;i++) ],lrT0_cT  
{ t(O{IUYM  
nStartPos = input.readLong(); {R2gz]v4  
nEndPos = input.readLong(); 6/m|Sg.m  
} TV~<1vj  
input.close(); MT8BP)C  
} x:h0/f  
catch(IOException e){e.printStackTrace ();} [Ch)6p  
catch(Exception e){e.printStackTrace ();} [7Yfv Xp  
} ;\F3~rl  
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@
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private void processErrorCode(int nErrorCode) DriJn`vtzq  
{ E|(T(4;  
System.err.println("Error Code : " + nErrorCode); s&<6{AU(id  
} 3HU_~%l  
\ 2$nFr?0  
+bG^SH2ke  
//停止文件下载 s~@4  
public void siteStop() ~w&P]L\dB  
{ QEe\1>1"&  
bStop = true; }=1#ANM1  
for(int i=0;i<nStartPos.length;i++) $*035f  
fileSplitterFetch.splitterStop(); bZ-"R 6a$  
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} vtvF)jlX  
} dE<}X7J%  
//负责部分文件的抓取 r[ UZHX5+S  
**FileSplitterFetch.java 3yWu-U \k  
*/
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package NetFox;  k3[%pS  
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*o}LI6_u  
import java.io.*; [jPUAr}  
import java.net.*; *}pl  
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public class FileSplitterFetch extends Thread { i8F^ N=  
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String sURL; //File URL v99gI%TA'  
long nStartPos; //File Snippet Start Position P}] xz Vy  
long nEndPos; //File Snippet End Position HN/ %(y  
int nThreadID; //Thread's ID d|^cKLu  
boolean bDownOver = false; //Downing is over uSeRn@  
boolean bStop = false; //Stop identical .AIlv^:|U  
FileAccessI fileAccessI = null; //File Access interface 5pF4{Jd1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :ET05MFs\#  
{ cR/-FR  
this.sURL = sURL; Pc+8CuN?  
this.nStartPos = nStart; mVJW"*}8  
this.nEndPos = nEnd; 1o&]=(  
nThreadID = id; IFrq\H0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f`zH#{u
  
}
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public void run() Fa
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{ :xn/9y+s  
while(nStartPos < nEndPos && !bStop) >k:BG{$Kae  
{ IO,ddVO  
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try{ {o2pCH
 
URL url = new URL(sURL); hxIG0d!o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dQ&S&SW  
httpConnection.setRequestProperty("User-Agent","NetFox"); f L @rv  
String sProperty = "bytes="+nStartPos+"-"; K+9oV[DMs  
httpConnection.setRequestProperty("RANGE",sProperty);
.AEOf0t  
Utility.log(sProperty); ZG=B'4W  
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InputStream input = httpConnection.getInputStream(); wv.FL$f[@  
//logResponseHead(httpConnection); !ke_?+8sY  
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byte[] b = new byte[1024]; -&4W0JK9  
int nRead; %9D$N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) eBZa9X$  
{ cY%[UK$l  
nStartPos += fileAccessI.write(b,0,nRead); XkB^.[B  
//if(nThreadID == 1) 'dE G\?v9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?\_N*NEtK
 
} 'ZyHp=RN)  
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Utility.log("Thread " + nThreadID + " is over!"); n5nV461U  
bDownOver = true; @,Je*5$o"  
//nPos = fileAccessI.write (b,0,nRead); #41fRmzC  
} HPc7Vo(  
catch(Exception e){e.printStackTrace ();} deD%E-Ja  
} r"yA=d'c  
} JsNqijVC  
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.C]V==z`[4  
//打印回应的头信息 ^P5+ _P  
public void logResponseHead(HttpURLConnection con) 3j{VpacZY  
{ ]1A"l!yf  
for(int i=1;;i++) 'b#`)w@/=  
{ 6`sOhVD  
String header=con.getHeaderFieldKey(i); Y2&>;ym!  
if(header!=null) )&G uZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h/h`?vWu  
Utility.log(header+" : "+con.getHeaderField(header)); DP2 ^(d<  
else m$T?~oo  
break; "qE
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} zdDn. vG  
} aq~g54  
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public void splitterStop() )@-v6;7b0  
{ RX-qL,dc  
bStop = true; UQGOCP_  
}
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} ~7Ji+AJA  
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/* */=5m]  
**FileAccess.java "NUl7ce.R  
*//文件访问(定位，写) f/spJ<B).4  
package NetFox; [Z2:3*5r.  
import java.io.*; /*5t@_0fe  
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public class FileAccessI implements Serializable{ C$X )I~M  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I }AO_rtb  
RandomAccessFile oSavedFile; ;#np~gL  
long nPos; zd)2@jX=  
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public FileAccessI() throws IOException Da#|}m0>  
{ (*63G4Nz\  
this("",0); W~15[r0  
} ld~8g,  
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public FileAccessI(String sName,long nPos) throws IOException DlB"o.  
{ hZ0p /Bdv  
oSavedFile = new RandomAccessFile(sName,"rw"); FA 1E`AdU  
this.nPos = nPos; G~Xh4*#J  
oSavedFile.seek(nPos); L8<Yk`jx  
} 3y!yz3E  
;Qpp`  
2ql7*g?Uq@  
public synchronized int write(byte[] b,int nStart,int nLen) :Jp$_T&E  
{ 4:$?u}9[:[  
int n = -1; :3qA7D}  
try{ &1hJ?uM01  
oSavedFile.write(b,nStart,nLen); $y!k)"k  
n = nLen; NB]T~_?]*  
} ^%X,Rml<e  
catch(IOException e) RX",Zt$q  
{ 6d~[My  
e.printStackTrace (); /1X0h  
} i2or/(u`  
]?P9M<0PM  
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return n; QJFx/zU  
} 6&(gp(F  
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} "65@8xt==  
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.pNPC|XU  
/* `Q2 `":  
**SiteInfoBean.java iE}jilU  
*/ S[fzy$">  
package NetFox; ]A}'jP
 
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public class SiteInfoBean { jd;=5(2  
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{r2-^QHF  
private String sSiteURL; //Site's URL YQ>P{I%J  
private String sFilePath; //Saved File's Path ;I'pC?!y  
private String sFileName; //Saved File's Name K~nk:}3Ui  
private int nSplitter; //Count of Splited Downloading File 7&G[mOx0  
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public SiteInfoBean() /ZAS%_as  
{//nSplitter的缺省值为5 -Z&6P
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//default value of nSplitter is 5 #84p
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this("","","",5); t0Q/vp*/  
} ~ei\~;n\@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DJ"O`qNV3  
{ t?^C9(;6  
sSiteURL= sURL; sMAc+9G9k  
sFilePath = sPath; $rf4h]&<  
sFileName = sName; dbGW`_zQ4  
this.nSplitter = nSpiltter; }?B=R#5  
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} %-@`|  
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public String getSSiteURL() >b;fhdd:4  
{ gBRhO^Sz  
return sSiteURL; )f4D2c&VE  
} {N+N4*  
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Y
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public void setSSiteURL(String value) 8:,E=swe  
{ -A}*Aa'\  
sSiteURL = value; P/._ tQu6  
} y|!%C-P  
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public String getSFilePath() yTw0\yiO  
{ po_||NIY  
return sFilePath; 4%O*2JAw  
} lp5`Kw\  
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#ej^K |Qx  
public void setSFilePath(String value) FKflN  
{ yn<z!z%mz  
sFilePath = value; Uh}n'Xd#{}  
} P8.tl"q  
iZ+\vO?|  
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public String getSFileName() yEt:g0Z\  
{ ,-Fhb~u  
return sFileName; i> Ssp  
} #=R)s0j"  
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public void setSFileName(String value) le`&VdE^  
{ )F 6#n&2  
sFileName = value; N m-{$U  
} VY8p[`  
D1bS=> ;,"  
#V[?puE@  
public int getNSplitter() |E-0P=h  
{ pmXx2T#=  
return nSplitter; qOz,iR?}  
} RsU=fe,  
")7,ZN;  
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public void setNSplitter(int nCount) 94r8DkI  
{ L1*P<Cb  
nSplitter = nCount; O!='U!X@P  
} Q17"hO>kC  
} {s|rk  
5gW`;Cdbyc  
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/* 1(M0C[P  
**Utility.java [.B)W);  
*/ \Q{@AC<?i  
package NetFox; &V1N a1`  
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public class Utility { "s2?cQv{#  
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public Utility() k
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{ c\U
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&oiX/UaY  
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} (6z^m?t?  
nL@ "FZ`(  
//线程睡眠 hC<X\yxe  
public static void sleep(int nSecond) 'P}"ZHW  
{ +V1EqC*  
try{ 8YraW|H  
Thread.sleep(nSecond); m_~ p G  
} qAm$yfYs`  
catch(Exception e) k(o[T),_%0  
{ W5(t+$L.  
e.printStackTrace (); y4)M,+O5  
} X`]-)(UX  
} G;V@oT  
/dhx+K~  
//日志 2F^ %d9`  
public static void log(String sMsg) ;6t>!2I>C  
{ PC/fb-J  
System.err.println(sMsg); KgVit+4u/  
} GmtMA|  
2.}<VivT  
`3kE$h#  
public static void log(int sMsg) Y\BB;"x1  
{
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System.err.println(sMsg); UT [7 J  
} m\7-/e2a  
} rB?u.jn0T  
E!Hq%L!/  
xq=+M!V  
/* F/ 2@%,2n  
**TestMethod.java Km]N scq1  
*/ JWy$` "{  
package NetFox; 1O45M/5\o  
2*n2!7jZ*  
- t4"BD  
public class TestMethod { u1`8f]qt  
KpC)A5u6  
\^;Gv%E  
public TestMethod() ^j';4'  
{ ///xx/weblogic60b2_win.exe :7Rs$ -*Uk  
try{ wc)[r~On(5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *x`z5_yfO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FFbMG:>:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <.
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fileFetch.start(); dJ?VN!B0  
} R%aH{UhE`  
catch(Exception e){e.printStackTrace ();} b@^M|h.Va  
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} ?Li^XONz  
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public static void main(String[] args) jp8=>mk  
{ C-qsyJgZy  
new TestMethod(); >tr?5iKxc  
} _4o2AS:j  
} 2F!K }aw  
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