http断点续传简单实现（java)

/* EwT"uL*V;  
**SiteFileFetch.java RJ&RTo  
*/ k5e;fA/w  
package NetFox; KC6.Fr{  
import java.io.*; 5d^sA;c  
import java.net.*; 69Ne
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public class SiteFileFetch extends Thread { i$#;Kpb`^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean sb*G!8j  
long[] nStartPos; //开始位置 !;{7-
~  
long[] nEndPos; //结束位置 HM1Fz\Sf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q`7PhA
  
long nFileLength; //文件长度 :\c ^*K(9  
boolean bFirst = true; //是否第一次取文件 ie95rZp  
boolean bStop = false; //停止标志 a#k6&3m&  
File tmpFile; //文件下载的临时信息 &h)yro  
DataOutputStream output; //输出到文件的输出流 6;d*r$0Fc  
1(R}tRR7R  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZvX*t)VjTz  
public SiteFileFetch(SiteInfoBean bean) throws IOException ECuH%b^,  
{ %)1?TU  
siteInfoBean = bean; i9|Sa6vuI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7Q9 w?y~c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [l??A
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if(tmpFile.exists ()) H$t_Xw==  
{ ?e4YGOe.  
bFirst = false; -@2iaQ(5a2  
read_nPos(); ltSU fI  
} k]|~>9eY]  
else $8h%a 8I  
{ lfgq=8d  
nStartPos = new long[bean.getNSplitter()]; /Cr%{'Pzk  
nEndPos = new long[bean.getNSplitter()]; xLajso1g69  
} o:'MpKm  
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}R2u@%n{  
} J]'zIOQ  
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public void run() iWkWR"ysy  
{ h,N?Ab'S  
//获得文件长度 i1d'nxk6  
//分割文件 EME|k{W  
//实例FileSplitterFetch ;JT-kw6l5K  
//启动FileSplitterFetch线程 `$9x1dx  
//等待子线程返回 a58H9w"u)  
try{ fTec  
if(bFirst) 9W5lSX#^;  
{ *N<]Xy@  
nFileLength = getFileSize(); V f&zL Sgr  
if(nFileLength == -1) "HIRTE;&  
{ sll\g  
System.err.println("File Length is not known!"); ]F~dlH1Wp
 
} ="H`V V_  
else if(nFileLength == -2) $s:aW^k  
{ #c!lS<z  
System.err.println("File is not access!"); 4+8@`f>s  
} f$$/H>MJ  
else "KpGlY?^  
{ H7n>Vx:L-  
for(int i=0;i<nStartPos.length;i++) 0{D'n@veP  
{ va@Lz&sAE%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k4J+J.|  
} !F$6-0%  
for(int i=0;i<nEndPos.length-1;i++) gwMNYMI  
{ F$]Pk|,  
nEndPos = nStartPos[i+1]; ZY+qA  
} d#FQc18v}k  
nEndPos[nEndPos.length-1] = nFileLength; oMa6(3T?E  
} I\ob7X'Xu!  
} lymCH  
NXrlk  
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//启动子线程 ^09,"<@k  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &h/Xku&0  
for(int i=0;i<nStartPos.length;i++) :"c*s4  
{ TvbE2Q;/UL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DvvK^+-~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZFL~;_r  
nStartPos,nEndPos,i); )y$(AJx$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #"~<HG}bR/  
fileSplitterFetch.start(); y<Ot)fa$  
} ~c `l@:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +mn[5Y}:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q;rX;p^W  
nEndPos = " + nFileLength); "chDg(jMZ  
// fileSplitterFetch[nPos.length-1].start(); e9B064  
iYy1!\  
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//等待子线程结束 {`@G+JV~Jw  
//int count = 0; b\2 ds,  
//是否结束while循环 %'pgGC"|  
boolean breakWhile = false; I!K6o.|1  
3!]rmZ-W  
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while(!bStop) > ~O.@|  
{ tWcHb #  
write_nPos(); VOLj>w  
Utility.sleep(500); gPPkT"  
breakWhile = true; WNtW|IV  
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for(int i=0;i<nStartPos.length;i++) <e6#lF
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{ OneY_<*a<  
if(!fileSplitterFetch.bDownOver) D&y7-/  
{ J|73.&B  
breakWhile = false; >hIu2jm  
break; &};zvo~P.  
} +NUG  
} abVmkdP_s  
if(breakWhile) eHUOU>&P]  
break; K[YyBEid  
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!4+<<(B=E  
//count++; ox.F%)eQ  
//if(count>4) $XH^~i;  
// siteStop(); OjA,]Gv6  
} JBZ@'8eqi]  
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System.err.println("文件下载结束！"); \  Cj7k^  
} f|gg  
catch(Exception e){e.printStackTrace ();} aN3;`~{9  
} ?a]mD
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+=)+'q]S  
//获得文件长度 jebx40TA3  
public long getFileSize() qH_Dc=~la  
{ "m>81-0  
int nFileLength = -1; Vxt+]5X  
try{ BZ^}J!Q'*  
URL url = new URL(siteInfoBean.getSSiteURL()); oXgcc*j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )+Pus~w  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5"H=zJ=r  
\~wMfP8  
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int responseCode=httpConnection.getResponseCode(); 9lE_nc  
if(responseCode>=400) >yDZ
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{ [2cD:JL  
processErrorCode(responseCode); mX|ojZ  
return -2; //-2 represent access is error q@2siI~W  
} pfI&E#:5  
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String sHeader; e+K^Aq  
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for(int i=1;;i++) Etm?'  
{ g9F?z2^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bg0

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//Utility.log(in.readLine()); \l3h0R  
sHeader=httpConnection.getHeaderFieldKey(i); m#p'iU*va,  
if(sHeader!=null) N{>n$v}  
{ > Nr#O  
if(sHeader.equals("Content-Length")) Rf1x`wml  
{ akQ7K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Oow2>F%
_#  
break; [Vt\$  
} 8dhUBJ0_  
} =vhm}  
else <a+Z;>  
break; QmIBaMI#  
} a'IdYW0  
} ? =+WRjF  
catch(IOException e){e.printStackTrace ();} E_LN]v  
catch(Exception e){e.printStackTrace ();} I2Yz#V<%ru  
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Utility.log(nFileLength); A5w6]:f2  
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return nFileLength; J$v?T$LVw  
} 1-QS~)+  
.%QXzIa3F  
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//保存下载信息（文件指针位置） W@!S%Y9  
private void write_nPos() ;9g2?-svw  
{ OZ!^ak  
try{ L8 @1THY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3f;>" P}  
output.writeInt(nStartPos.length); S21,VpW\  
for(int i=0;i<nStartPos.length;i++) t0?\l)  
{ POR\e|hRT]  
// output.writeLong(nPos); L j$;:/G  
output.writeLong(fileSplitterFetch.nStartPos); \nqS+on]  
output.writeLong(fileSplitterFetch.nEndPos);
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} }o{
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output.close(); &jr3B;g!C  
} KY
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catch(IOException e){e.printStackTrace ();} N,U8YO  
catch(Exception e){e.printStackTrace ();} ;jTN| i'  
} 7"xd1l?zz  
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//读取保存的下载信息（文件指针位置） nt.y !k  
private void read_nPos() WOf 4o  
{ 4v|W-h"K  
try{ L&OwPd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 61 ~upQaR  
int nCount = input.readInt(); t&Og$@  
nStartPos = new long[nCount]; BL58] P84  
nEndPos = new long[nCount]; xAP+FWyV  
for(int i=0;i<nStartPos.length;i++) $u6 3]rypm  
{ '[O;zJN;  
nStartPos = input.readLong(); h`.&f  
nEndPos = input.readLong(); y18Y:)DkL  
} &G$Ucc `  
input.close(); 9]@!S|1  
} P L+sR3bR  
catch(IOException e){e.printStackTrace ();} s&J]zb`  
catch(Exception e){e.printStackTrace ();} R_xRp&5  
} /|#fejPh  
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private void processErrorCode(int nErrorCode) v74&BL]a
 
{ 0Fr?^3h  
System.err.println("Error Code : " + nErrorCode); Oz#{S:24M+  
} d*Fj3Wkx  
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//停止文件下载 VOh4#%Vj  
public void siteStop() $,fX:x  
{ y L~W.H  
bStop = true; 5QO9Q]I#_\  
for(int i=0;i<nStartPos.length;i++) Jqi%|,/]N  
fileSplitterFetch.splitterStop(); -C&P%tt Y  
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} @!d{bQd,  
}  1ZB"EQ  
//负责部分文件的抓取 _8agtQ:<  
**FileSplitterFetch.java $]2vv
r  
*/ !_Z&a  
package NetFox; R_S.tT!  
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import java.io.*; 2T[9f;jM'  
import java.net.*; $a ` G  
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public class FileSplitterFetch extends Thread { Nu~lsWyRI5  
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String sURL; //File URL TrR8?-  
long nStartPos; //File Snippet Start Position ]L}dzA?:
 
long nEndPos; //File Snippet End Position j^2j&Ta  
int nThreadID; //Thread's ID v1,oilL  
boolean bDownOver = false; //Downing is over gr-OHeid  
boolean bStop = false; //Stop identical @49S`  
FileAccessI fileAccessI = null; //File Access interface 0Pi:N{x8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ('p5:d  
{ P J[`|  
this.sURL = sURL; R0  
this.nStartPos = nStart; K@w{"7}  
this.nEndPos = nEnd; 0NX,QD  
nThreadID = id; b9dLt6d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0%I=d  
} I4?5K@a  
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public void run() ayF\nk4b  
{ t}/( b/VD  
while(nStartPos < nEndPos && !bStop) 2P{Gxz<#  
{ [Cv/{f3]u{  
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try{ u> In(7\  
URL url = new URL(sURL); z7$}#)Z7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6 cr^<]v!  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uc>LFX& -B  
String sProperty = "bytes="+nStartPos+"-"; o[H\{a>  
httpConnection.setRequestProperty("RANGE",sProperty); |<2JQ[]  
Utility.log(sProperty); iqlVlm>E  
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InputStream input = httpConnection.getInputStream(); t;~-_{
  
//logResponseHead(httpConnection); FrgV@4'2G  
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byte[] b = new byte[1024]; 7@\GU].2  
int nRead; #s/{u RYQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hG[4O3jo\  
{
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nStartPos += fileAccessI.write(b,0,nRead); )m>6hk  
//if(nThreadID == 1) Wpa$B )xg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EsNk<Ra  
} PH{c,  
4jPwL|#  
]b!R-G!gV  
Utility.log("Thread " + nThreadID + " is over!"); 's/27=o  
bDownOver = true; >cSi/a,L  
//nPos = fileAccessI.write (b,0,nRead); $R3.yX=[\  
} %!#rrt,F  
catch(Exception e){e.printStackTrace ();} =`ywd]\7  
} `,Q<YT ~  
} ] +sSg=N7i  
>dcqPNDg1^  
1_XO3P\  
//打印回应的头信息 nN!vgn j  
public void logResponseHead(HttpURLConnection con) la1D2 lM  
{ MH2OqiCI  
for(int i=1;;i++) <m:4g ,6  
{ C!
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String header=con.getHeaderFieldKey(i); RbyF#[}  
if(header!=null) |^\Hv5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ``/y=k/au  
Utility.log(header+" : "+con.getHeaderField(header)); ?cA8P.?^A  
else aslNlH6  
break; _g^E%@'W  
} Rs^jk)Z:)  
} x*k65WO\  
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public void splitterStop() 20S9/9ll  
{ fB@K'JQG  
bStop = true; $a)JCErN  
} hG< a  
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} `,hW;p>-  
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0]/,m4a#n  
/* 5?S{W  
**FileAccess.java []sB^UT  
*//文件访问(定位，写) Y8{T.\%\+  
package NetFox; M^!C?(Hx^x  
import java.io.*; zWP.1 aA&  
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3W%f#d$`  
public class FileAccessI implements Serializable{ A} x_zt  
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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 >;T$#LZ  
RandomAccessFile oSavedFile; "P>$=X~Zi  
long nPos; 5(mCBH  
.`i'gPLkn2  
,'/HcF?yf  
public FileAccessI() throws IOException IF,i^,  
{ %5( EkP  
this("",0); :e5:\|5*5  
} z_)OWWdN  
>e5q2U   
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public FileAccessI(String sName,long nPos) throws IOException tU-#pB>H  
{ "\wDS2M)  
oSavedFile = new RandomAccessFile(sName,"rw"); FB?q/_  
this.nPos = nPos; c%6 @ z  
oSavedFile.seek(nPos); Y`E{E|J  
} Xs.$2  
&mO/u
=u  
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public synchronized int write(byte[] b,int nStart,int nLen) uM}dZp 1  
{ 9Y!0>&o  
int n = -1; DkF@XK0c3  
try{ )U"D4j*p  
oSavedFile.write(b,nStart,nLen); {d*qlztO  
n = nLen; ~(*co[_  
} 6qmo ZAg  
catch(IOException e) E#&c]9QM75  
{ 4F1
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e.printStackTrace (); r P<d[u  
} 3thG*^C5  
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X=*Yzz}  
return n; 5KA FUR0  
} hr$VVbOho  
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} RX3P%xZ  
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/* `KgIr,Q)  
**SiteInfoBean.java HG{r\jh
 
*/ \4zb9CxOZ  
package NetFox; O0[.*xG  
5srj|'ja  
#-r,;  
public class SiteInfoBean {  74i  
}}y~\TB~}  
~`~mnlN  
private String sSiteURL; //Site's URL ))JbROBU,  
private String sFilePath; //Saved File's Path ~\<aj(m(|  
private String sFileName; //Saved File's Name 7#wdBB%  
private int nSplitter; //Count of Splited Downloading File wa7)  
] ;"blB  
V~([{
 
public SiteInfoBean() N{w)}me[YY  
{//nSplitter的缺省值为5 wC{?@h  
//default value of nSplitter is 5 I:?1(.kd2-  
this("","","",5); m_ >+$uL  
} '@t}8J  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5'*v-l,[  
{ 4'9yMXR  
sSiteURL= sURL; K)=<hL  
sFilePath = sPath; M*6}#ST  
sFileName = sName; ;iEr+  
this.nSplitter = nSpiltter; "-bsWC  
4AA3D!$  
KVQ|l,E, /  
} XpS].P9  
!} ~K'1"  
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public String getSSiteURL() %+0 7>/  
{ 98O0M#|d  
return sSiteURL; @'XxMO[Z!<  
} ~ A?  

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cVk&Yp;[*  
public void setSSiteURL(String value) b9FfDDOq"  
{ fdk]i/*)  
sSiteURL = value; H& L  
} AXBf\)[  
iY_E"$}P  
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public String getSFilePath() I#?NxP\S  
{ u^5X@.  
return sFilePath; 98"/]ER
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} iPoh2  

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public void setSFilePath(String value) U5_1-wV  
{ eksYIQZ]  
sFilePath = value; !LDuCz -  
} tw{V7r~n  
WJD1U?`  
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public String getSFileName() 8&q|*/2  
{ l# -4}95  
return sFileName; Y8*k18~  
} #. mc+n:I  
[(%6]L}  
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public void setSFileName(String value) P F#X8+&J  
{ (``EBEn  
sFileName = value; -N'xQ(#n3q  
} bf~gWzA  
l| /tKW  
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public int getNSplitter() ' KX'{Gy  
{ k-o(Q"[ '  
return nSplitter; PQ}q5?N  
} RPb/U8  
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&``dI,NC  
public void setNSplitter(int nCount) #Y)Gos  
{ Z^Y_+)
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nSplitter = nCount; +4[L_  
} a(!_3i@  
} 2&L2G'  
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-!X,MDO  
/* T6 K?Xr{_  
**Utility.java i5oV,fiZo  
*/ Oa[G #  
package NetFox; 
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public class Utility { `RRC8]l  
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public Utility() D%tcYI(  
{ aT v  
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LyEM^d]  
} .}AzkKdd@  
'QR @G  
//线程睡眠 fc}G6P;3{  
public static void sleep(int nSecond) HM'P<<  
{ l4 @  
try{ :/F=j;o  
Thread.sleep(nSecond); }sbh|#  
} V$D+Joj
 
catch(Exception e) mM6g-)cV  
{ {*/&`$0lH|  
e.printStackTrace (); g;N)K3\2
 
} 80i-)a\n  
} ]u;Ma G=;  
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//日志 );8Nj zX1  
public static void log(String sMsg) OxGS{zs  
{ \S]"nHX  
System.err.println(sMsg); $:{r#mM  
} o\n9(ao  
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public static void log(int sMsg) @P
1#)  
{ 4#pn]  
System.err.println(sMsg); wi7a_^{  
} 3^ct;gz  
} B%~hVpm,eM  
5xHP5+&  
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/* z>\vYR$  
**TestMethod.java +<
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*/ `v]|x,l+C  
package NetFox; yvPcD5s5  
})I_@\q  
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public class TestMethod { .?16w`Y  
X:aLed_{f  
C\~!2cy  
public TestMethod() =5a|'O  
{ ///xx/weblogic60b2_win.exe J}$St|1y  
try{ In[!g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C-vFl[@a0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ("G _{tVU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -tQi~Y[]  
fileFetch.start(); sZ-A~X@g  
} {P/5cw  
catch(Exception e){e.printStackTrace ();} /QA:`_</oh  
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G
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} $#b@b[h<w  
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public static void main(String[] args) +3;`4bW  
{ cip"
9|"  
new TestMethod(); {LwV&u(  
} K *<+K<Tp  
} *%[L @WF  
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