http断点续传简单实现（java)

/* x_r*<?OZ  
**SiteFileFetch.java B<0Kl.V  
*/ QNH3\<IS  
package NetFox; z"Mk(d@-E  
import java.io.*; mhB2l/  
import java.net.*; ij
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public class SiteFileFetch extends Thread { AREjS$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +wf9!_'  
long[] nStartPos; //开始位置 5lM2nhlf'b  
long[] nEndPos; //结束位置 I&31jn_o /  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 # 1dg%  
long nFileLength; //文件长度 AQmHa2P  
boolean bFirst = true; //是否第一次取文件 _,/~P)  
boolean bStop = false; //停止标志 );kD0FO1|  
File tmpFile; //文件下载的临时信息 qG ? :Q  
DataOutputStream output; //输出到文件的输出流 n>w<vM  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） IdK<:)Q
 
public SiteFileFetch(SiteInfoBean bean) throws IOException n2EPx(~  
{ Hq!|r8@6  
siteInfoBean = bean; *ifz@8C }  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5{Q9n{dOh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p4 =/rkq  
if(tmpFile.exists ()) ,Vw>3|C  
{ hS&l4 \I'Z  
bFirst = false; ,~DV0#"  
read_nPos(); ZvMU3]
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} _54gqD2C,  
else } !y5hv!_  
{ LD1&8kJ*l  
nStartPos = new long[bean.getNSplitter()]; cnI5G!  
nEndPos = new long[bean.getNSplitter()]; @bJIN]R  
} ^39lUKL  
: ^("L,AF  
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} )BvMFwQG  
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public void run() K/K-u  
{ I]E 3&gnC  
//获得文件长度 Qd{8.lB~LQ  
//分割文件 qR_>41JU"  
//实例FileSplitterFetch ^'a#FbMtt  
//启动FileSplitterFetch线程 bwH[rT!n  
//等待子线程返回 WTJ{M$  
try{ p4*L}Q  
if(bFirst) *tgu@9b  
{ tW/g0lC%  
nFileLength = getFileSize(); 8|)^m[c&  
if(nFileLength == -1) @XXPJq;J  
{ WgqSw%:$H  
System.err.println("File Length is not known!"); gWzslgO6  
} RB4 +"QUh  
else if(nFileLength == -2) _+'!l'`  
{ -Ep#q&\  
System.err.println("File is not access!"); %,~?;JAj  
} 28`s+sH  
else KmTFJ,iM  
{ w"wW0uE^  
for(int i=0;i<nStartPos.length;i++) M/dgW`c  
{ @uldD"MJ<]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X;N?L%Pp  
} ^'0N%`bY!  
for(int i=0;i<nEndPos.length-1;i++) hlB\Xt  
{ yDwh]t  
nEndPos = nStartPos[i+1]; WFh.oe8  
} (D) KU9B>  
nEndPos[nEndPos.length-1] = nFileLength; $`55
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} _p*8ke  
} N)GHQlgH  
G(TFv\`vH  
9$HBKcO  
//启动子线程 )c{>@WM~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3ie k>'T  
for(int i=0;i<nStartPos.length;i++) )N8b
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{ {;u,04OVK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PPr Pj^%z=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M{{kO@P"9  
nStartPos,nEndPos,i); BEvY&3%l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bo/9k 4N3  
fileSplitterFetch.start(); X<$Tn60,  
} &h5Y_no GX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fy4zBI@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q_|}~4_+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %DYh<U4N  
nEndPos = " + nFileLength); "(7y%TFt:  
// fileSplitterFetch[nPos.length-1].start(); <D~hhGb  
T\uIXL?3  
_huJ*W7lR  
//等待子线程结束 e;"J,7@  
//int count = 0;
E|"SMA,  
//是否结束while循环 l|?tqCT ^h  
boolean breakWhile = false; Nw1*);b[y  
8O9^g4?  
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while(!bStop) LhbdvJAk@  
{ Hf?@<4  
write_nPos(); ,3Q~X$f  
Utility.sleep(500); w;`Jj-  
breakWhile = true; $|-Lw!)D  
>5Yn`Fc5  
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for(int i=0;i<nStartPos.length;i++) Y~g{9 <!  
{ P'lnS&yA  
if(!fileSplitterFetch.bDownOver) t-iXY0%&  
{ b;UBvwY_  
breakWhile = false; tfGs|x  
break; R+Hu?Dv&F  
} |p&EP2?T  
} BZ?3=S1*  
if(breakWhile) S3ooG14Ls  
break; eV|N@  
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//count++; {x_.QWe5  
//if(count>4) Y:ly x-lj  
// siteStop(); e=OHO,74z"  
}
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System.err.println("文件下载结束！"); OR+qi*)  
} ZyUcL_  
catch(Exception e){e.printStackTrace ();} w~b:9_reY  
} $:F+Nf 8  
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>0{}tRm-P&  
//获得文件长度 SWV*w[X<X  
public long getFileSize() U.Mfu9}#:  
{ V2Vr7v=Y"  
int nFileLength = -1; f[k#Znr  
try{ iH }-  
URL url = new URL(siteInfoBean.getSSiteURL()); q5SPyfE[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *=!e,  
httpConnection.setRequestProperty("User-Agent","NetFox"); OB(oOPH  
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int responseCode=httpConnection.getResponseCode(); kWXLncE  
if(responseCode>=400) PR.3EL  
{ ,*
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processErrorCode(responseCode); Q%JI-&K  
return -2; //-2 represent access is error ~Kw#^.$3T  
} fZo#
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String sHeader; q
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for(int i=1;;i++) p0@^1  
{ ;t{q]"? W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?uq`|1`  
//Utility.log(in.readLine()); ApCU|*r)  
sHeader=httpConnection.getHeaderFieldKey(i); WPL@
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if(sHeader!=null) ukSv70Ev  
{ G tI )O}  
if(sHeader.equals("Content-Length")) F}nwTras  
{ 7Bp7d/R-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2|je{  
break; A`Z/B[)  
} kXSX<b<%  
} uAn}qrqE9  
else ,2S!$M  
break; %qoS(iO`h  
} 1hG#  
} z%wh|q  
catch(IOException e){e.printStackTrace ();} +-!E%$
 
catch(Exception e){e.printStackTrace ();} m\`>N_4*9  
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Utility.log(nFileLength); ,dIev<  
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 ? }M81  
return nFileLength; ,;`f* #  
} Y,}_LS$f  
Jl/wP  
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//保存下载信息（文件指针位置） _ox+5?>  
private void write_nPos() b7QE  
{ L^sjV/\oW  
try{ *LEy#N
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); oACAC+CP  
output.writeInt(nStartPos.length); CxFd/X,  
for(int i=0;i<nStartPos.length;i++) yH/A9L,Z  
{ .e~"+Pe6b  
// output.writeLong(nPos); UT<e/  
output.writeLong(fileSplitterFetch.nStartPos); 5RP kAC  
output.writeLong(fileSplitterFetch.nEndPos); .{V"Gn9!  
} yix[zfQt0  
output.close(); 6zi>Q?] 1  
} sey,J5?  
catch(IOException e){e.printStackTrace ();} %k!CjW3  
catch(Exception e){e.printStackTrace ();} a`!Jq'  
} = s&Rk~2b/  
nuce(R  
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//读取保存的下载信息（文件指针位置） gQn%RPMh  
private void read_nPos() N''QQBUD  
{ yKc-:IBb{u  
try{ w' 7sh5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /{^k8 Q  
int nCount = input.readInt(); @Vm*b@  
nStartPos = new long[nCount]; Og\k5.! ,  
nEndPos = new long[nCount]; ;k<dp7^  
for(int i=0;i<nStartPos.length;i++) 80=0S^gEZ  
{ :7v'[b  
nStartPos = input.readLong(); BQ-x#[%s  
nEndPos = input.readLong(); 6_j |@  
} &$MC!iMh  
input.close(); n>Ff tVZNJ  
} C96/   
catch(IOException e){e.printStackTrace ();} !jj`Ht)  
catch(Exception e){e.printStackTrace ();} P%3pM*.  
} :X0L6y)u  
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=
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private void processErrorCode(int nErrorCode) k
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{ ?KC
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System.err.println("Error Code : " + nErrorCode); nKx)R^]k  
} Tuln#<:  
-o ).<&#  
FdU]!GO-X  
//停止文件下载 ^hIdmTf6  
public void siteStop() 7r:h_r-  
{ '~[8>Q>  
bStop = true; ,Bk5(e  
for(int i=0;i<nStartPos.length;i++) ]~TsmR[  
fileSplitterFetch.splitterStop(); }HgG<.H>  
@>2pY_  
+9_Y0<C  
} EeuYRyK  
} EQ1**[$  
//负责部分文件的抓取 ] ,|,/~  
**FileSplitterFetch.java zHJCXTM  
*/ =X$ieXq|  
package NetFox; )^j_O^T5  
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import java.io.*; P?0X az  
import java.net.*; <Ky-3:pxeM  
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public class FileSplitterFetch extends Thread { =nEP:7~{  
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String sURL; //File URL U+S=MP }:  
long nStartPos; //File Snippet Start Position cAWn*%  
long nEndPos; //File Snippet End Position =xI;D,@S  
int nThreadID; //Thread's ID (@?mm  
boolean bDownOver = false; //Downing is over Rlq7.2cP  
boolean bStop = false; //Stop identical oTw!#Re)  
FileAccessI fileAccessI = null; //File Access interface F? #3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <FT7QO$I  
{ ,B
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this.sURL = sURL; (5yM%H8:  
this.nStartPos = nStart; :/5m D  
this.nEndPos = nEnd; pjeNBSu6  
nThreadID = id; sZ `Tv[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n$iX6Cd  
} =?i?-6M  
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public void run() VvhfD2*T  
{ 1Bh"'9-!JT  
while(nStartPos < nEndPos && !bStop) T ,lM(2S[  
{ }3Es&p$9  
+3v)@18B1  
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try{ e5L+NPeM6v  
URL url = new URL(sURL); l<=;IMWd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _7c3=f83  
httpConnection.setRequestProperty("User-Agent","NetFox"); s(,S~  
String sProperty = "bytes="+nStartPos+"-"; =ZgueUz,  
httpConnection.setRequestProperty("RANGE",sProperty); PxkV[nbS  
Utility.log(sProperty); JF=R$!5  
_4S^'FDo   
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InputStream input = httpConnection.getInputStream(); Xoj"rR9|  
//logResponseHead(httpConnection); !>`Q]M`  
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byte[] b = new byte[1024]; bvox7V>  
int nRead; "HOZ2_(o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Sn=6[RQ>P  
{ ptCF))Zm'  
nStartPos += fileAccessI.write(b,0,nRead); \:vF FK4a  
//if(nThreadID == 1) "{0G,tdA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ot=>~(u0  
} THrLX;I  
,KY;NbL-Jp  
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Utility.log("Thread " + nThreadID + " is over!"); E|O&bUMh  
bDownOver = true; At7!Pas#@g  
//nPos = fileAccessI.write (b,0,nRead); ]N>ZOV,>  
} #:)'D?,  
catch(Exception e){e.printStackTrace ();} sI>w#1.m/&  
} 0seCQANd  
} g6M>S1oOO  
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//打印回应的头信息 ]c(FgYc  
public void logResponseHead(HttpURLConnection con) 
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{ PRhC1#  
for(int i=1;;i++) Wf~^,]9N  
{ w-|Rb~XT h  
String header=con.getHeaderFieldKey(i); @|gG3  
if(header!=null) UHl3/m7g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]ch=@IV  
Utility.log(header+" : "+con.getHeaderField(header)); C,|&  
else XC<fNK  
break; >"W^|2
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} j<AOC?  
} P{Nvt/%  
>y%H2][  
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public void splitterStop() TKZtoQP%  
{ TOG:`F
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bStop = true; 7[ ovEE54  
} N[{rsUBd  
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} ZFZ'&"+  
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/* } z'Jsy[s  
**FileAccess.java @Q1!xA^S  
*//文件访问(定位，写) j>k ;Zj  
package NetFox; z{XB_j6\=  
import java.io.*; /@LkH$  
ing'' _  
4D65VgVDM  
public class FileAccessI implements Serializable{ **q8vhJM  
@?B+|*cm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h,LSqjf"  
RandomAccessFile oSavedFile; 5U84*RY  
long nPos; U,rI/'  
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public FileAccessI() throws IOException jcCAXk055  
{ b4L7M1l  
this("",0); 196aYLE  
} u
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public FileAccessI(String sName,long nPos) throws IOException teok*'b:  
{ 6[m~xegG  
oSavedFile = new RandomAccessFile(sName,"rw"); H/a gt  
this.nPos = nPos; eMGJx"a  
oSavedFile.seek(nPos); z}vT8qoX  
} 6wlLE5  
&h:4TaD  
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public synchronized int write(byte[] b,int nStart,int nLen) ()lgd7|+  
{ EjP;P}_iK  
int n = -1; 6,t6~Uo/  
try{ & SXw=;B  
oSavedFile.write(b,nStart,nLen); yP58H{hQM8  
n = nLen; 7?dWAUF  
} O-, "/Z  
catch(IOException e) b++r#Q g  
{ ,_V V;P  
e.printStackTrace (); BJ UG<k  
} :zL)O  
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return n; D||0c"E  
} LOUP  
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} Jm_)}dj3o  
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V%-hP~nyBx  
/* V60L\?a  
**SiteInfoBean.java Q[OwP  
*/ .`D'eS6b  
package NetFox; ItVN,sVJb  
x%dny]O1;  
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public class SiteInfoBean { %lCZ7z2o  
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private String sSiteURL; //Site's URL g*$2qKm  
private String sFilePath; //Saved File's Path 12`u[O}\}-  
private String sFileName; //Saved File's Name >axeUd+@i  
private int nSplitter; //Count of Splited Downloading File w$ 8r<?^3  
cSt)Na~C  
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public SiteInfoBean() R3B+vLGX  
{//nSplitter的缺省值为5 qO{z{@jo55  
//default value of nSplitter is 5 ` GF w?G  
this("","","",5); P<pv@l9)  
} ~b_DFj  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,z&S;
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{ <rzP  
sSiteURL= sURL; dN2JOyS  
sFilePath = sPath; NK|UeL7ght  
sFileName = sName; GxdAOiq;  
this.nSplitter = nSpiltter; &nEL}GM)E  
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#xtH6\X  
} xmg3,bO  
eiK_JPFA-  
*PF<J/Pr  
public String getSSiteURL() .n<vhLDQn  
{ _LJF:E5L  
return sSiteURL; 2yA)SGri  
} U[wx){[|  
9c^,v_W@  
~0MpB~ {xd  
public void setSSiteURL(String value) =E9\fRGU  
{ /8GdCac  
sSiteURL = value; KF(H >gs  
} 4aO/^Hl  
=:rg1wo"c  
$tZ {>!N  
public String getSFilePath() SAP/jD$5]>  
{ Vk{
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return sFilePath; 9KVJk</:n  
} C|ZPnm>f30  
V'vWz`#  
`'1g>Ebk0  
public void setSFilePath(String value) d]DV\*v  
{ |5 V0_79  
sFilePath = value; y[m,t}gi  
} I?rB7*:  
 [ <X%
 
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public String getSFileName() 'rB%a<  
{ ]oP1c-GEk  
return sFileName; !|[rh,e]  
} ;
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public void setSFileName(String value) o=Vs)8W  
{ &jJu=6 U B  
sFileName = value; [xqV`(vM  
} 6?a`'&  
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public int getNSplitter() 7ws<' d7/  
{ a{`hAI${  
return nSplitter; ~HmH#"VP  
} h%/BZC^L]|  
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D?n6h\h\$%  
public void setNSplitter(int nCount) ?Bf>G]zx  
{ Yc[umn^K  
nSplitter = nCount; `w!XO$"]Z  
} c5ij2X|I  
} Y5aG^wE[:  
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^8 VW$}  
/* KW:N 6w  
**Utility.java B%tF|KKj  
*/ $7q3[skH  
package NetFox; yXU.PSG*  
nQc,^A)I  
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public class Utility { 'D21A8*N  
{;{U@Z  
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public Utility() N`
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{ kyHli~Nr"  
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} NzT &K7v  
i.E2a)  
//线程睡眠 %axr@o[  
public static void sleep(int nSecond) x_Ev2 c'4  
{ Ja6KO2}p  
try{ 6*Z7JiQ0  
Thread.sleep(nSecond); .lcp5D[(  
} t'eaR-  
catch(Exception e) Wk[a|>  
{ `vBBJ@f4)  
e.printStackTrace (); Wj.t4XG!  
} QXb2jWz  
} L"b&O<No  

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//日志 S)U*1t7[  
public static void log(String sMsg) |.)LZP,  
{ ]^ R':YE  
System.err.println(sMsg); uU^DYgs  
} y-hTTd"{  
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>/n];fl>8  
public static void log(int sMsg) 8"&!3_  
{ d2
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System.err.println(sMsg); b<tV>d"Fv  
} <D|&)/#  
} mz0{eO  
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k{2Gq1S{  
/* 33~MP;  
**TestMethod.java >`
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*/ 0z/*JVka  
package NetFox; Tf3CyH!k  
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4v_Ac;2m&  
public class TestMethod { RZHfT0*jL  
x'L=p01  
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public TestMethod() @\?HlGWEf  
{ ///xx/weblogic60b2_win.exe
m.+h@  
try{ OH/9<T
?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :A8r{`R'N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KtaoOe  
SiteFileFetch fileFetch = new SiteFileFetch(bean); af|h4.A  
fileFetch.start(); Sqa9+' [  
} 5qM$ahN3wH  
catch(Exception e){e.printStackTrace ();} 7{<v$g$  
0)|Z7c&  
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} RL` jaS?V  
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public static void main(String[] args) DQ8/]Z{H  
{ 8-<F4^i_i  
new TestMethod(); yhKH} kR  
} .'`aX 7{\  
} i`+w.zJOH8  
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