http断点续传简单实现（java)

/* zW nR6*\  
**SiteFileFetch.java :v 4]D4\o  
*/ B7%U_F|m  
package NetFox; FgO)DQm  
import java.io.*; _vZOZKS+  
import java.net.*; wyG;8I  
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:hA#m[  
public class SiteFileFetch extends Thread { E\$W_Lmr  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c`Wa^(  
long[] nStartPos; //开始位置 -{A<.a3P}=  
long[] nEndPos; //结束位置 o"SMbj  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GKCroyor  
long nFileLength; //文件长度 9!tW.pK5  
boolean bFirst = true; //是否第一次取文件 \j.:3Xr  
boolean bStop = false; //停止标志 @ .KGfNu  
File tmpFile; //文件下载的临时信息 FPTK`Gd0  
DataOutputStream output; //输出到文件的输出流 h7@6T+#WoT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mVmGg,  
public SiteFileFetch(SiteInfoBean bean) throws IOException I2DpRMy  
{ J8~ha
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siteInfoBean = bean; 9>$p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -Qe Z#w|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A\;U3Zu  
if(tmpFile.exists ()) Wez5N  
{ O'~+_ykTl  
bFirst = false; BORA(,  
read_nPos(); U;I9 bK8  
} Aa]"  
else U<-D(J
  
{ F5#YOck&,  
nStartPos = new long[bean.getNSplitter()]; 8$|=P!7EO  
nEndPos = new long[bean.getNSplitter()]; )CyS#j#=  
} $]8Q(/mbK  
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} :i7;w%
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public void run() cS+>J@L  
{ Vq2$'lY  
//获得文件长度 P }uOJVQ_  
//分割文件 -%dCw6aX+  
//实例FileSplitterFetch ]cruF#`%  
//启动FileSplitterFetch线程 *9i{,I@  
//等待子线程返回 KGpA2Nx  
try{ ]:\dPw
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if(bFirst) .x1NWGDn  
{ 8.~kK<)!  
nFileLength = getFileSize(); D sWSGb  
if(nFileLength == -1)  Mc}^LDX  
{ 6`-jPR  
System.err.println("File Length is not known!"); UY2OZ&&  
} c0fo7|  
else if(nFileLength == -2) >"<Wjr8W!$  
{ 3D(0=$W  
System.err.println("File is not access!");  RX5dO%  
} nNU2([  
else xP,hTE  
{ #5j\C+P}|  
for(int i=0;i<nStartPos.length;i++) qyNyBr?  
{ j8`BdKg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~3 bPIg7D  
} BF<ikilR  
for(int i=0;i<nEndPos.length-1;i++) 4a]P7fx-  
{ ]g&TKm  
nEndPos = nStartPos[i+1]; GM<-&s!Uj  
} ofv)SCjd  
nEndPos[nEndPos.length-1] = nFileLength; &8 x-o,  
}
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} !0cD$^7  
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//启动子线程 ZQ0F$J)2~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nj53G67y  
for(int i=0;i<nStartPos.length;i++) "FKOaQ%IH  
{ {Dmjm{   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uRr o?m<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3Ims6I]  
nStartPos,nEndPos,i); LE>]8[f6S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d<N:[Y\4l  
fileSplitterFetch.start(); h2""9aP!  
} \;"=QmRD%:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iW /}#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b%/ 1$>_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <3hRyG@vB  
nEndPos = " + nFileLength); ilx)*Y  
// fileSplitterFetch[nPos.length-1].start(); qeZ? 7#Gf  
0s2v'A[\  
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//等待子线程结束 fsWTF<Y  
//int count = 0; hFl^\$Re  
//是否结束while循环 Fun^B;GA:  
boolean breakWhile = false; n#OB%@]<V  
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.UY^oR=b{  
while(!bStop) ;x@~A^<el  
{ u^qT2Ss0  
write_nPos(); exUu7&*:  
Utility.sleep(500); _t #k,;  
breakWhile = true; lv+TD!b   
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for(int i=0;i<nStartPos.length;i++) wov\kV  
{ zuy4G9P  
if(!fileSplitterFetch.bDownOver) JB[~;nLlC  
{ *.d)OOpLo  
breakWhile = false; Y^EcQzLw  
break; =.]4;z  
} XLOh7(  
} 'Xq|Kf (  
if(breakWhile) FZslv"F  
break; 8i#2d1O  
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//count++; 0*D$R`$  
//if(count>4) GM f `A,>  
// siteStop(); ofw3S|F6  
} LR.<&m%~.  
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System.err.println("文件下载结束！"); G.abql  
} My[pr_xg  
catch(Exception e){e.printStackTrace ();} e_ANUll1  
} Y;^l%ePuW  
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//获得文件长度 W^LY'ypT  
public long getFileSize() c"V"zg22  
{ 'UX!*5k<:  
int nFileLength = -1; k(7&N0V%zz  
try{ -23w2Qt  
URL url = new URL(siteInfoBean.getSSiteURL()); xvl#w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q"sed]  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]i ,{  
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int responseCode=httpConnection.getResponseCode(); [KaAXv .X  
if(responseCode>=400) ?u=Fj_N_  
{ jaMjZp;{(  
processErrorCode(responseCode); f:|1_j  
return -2; //-2 represent access is error s6v;  
} j0S#>t  
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String sHeader; l
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for(int i=1;;i++) ~>Fu5i $i  
{ RD'Q :W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0gy/:T  
//Utility.log(in.readLine()); bvr^zH,C  
sHeader=httpConnection.getHeaderFieldKey(i); T?soJ]A  
if(sHeader!=null) wb5baY9  
{ +wvWwie  
if(sHeader.equals("Content-Length")) o_Z5@F  
{ A8fOQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i,E{f  
break; NI}yVV  
} wh\}d4gN  
} !&ayYu##{  
else +N9X/QFKV  
break; \y)rt )  
} C]eSizS.  
} [.8BTj1%  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} W*4-.*U8a  
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Utility.log(nFileLength); )}]g] g  
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return nFileLength; Lh"<XYY  
} {3p4:*}  
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//保存下载信息（文件指针位置） .b&t;4q  
private void write_nPos() a %'the  
{ trA4R/ &  
try{ OwUhdiG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2c,9e`  
output.writeInt(nStartPos.length); 0hNA1Fh{U  
for(int i=0;i<nStartPos.length;i++) 9ni1f{k  
{ }6}l7x  
// output.writeLong(nPos); swoQ'  
output.writeLong(fileSplitterFetch.nStartPos); [0[i5'K:  
output.writeLong(fileSplitterFetch.nEndPos); @* jz o  
} S8w _ii3zd  
output.close(); qu6D 5t  
} C12Fl  
catch(IOException e){e.printStackTrace ();} Oo8VeRZ  
catch(Exception e){e.printStackTrace ();} V/LLaZTE  
} 2K6qY)/_  
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//读取保存的下载信息（文件指针位置） m6K}|j  
private void read_nPos() Z1f8/?`W  
{ x0D*U?A  
try{ n;C :0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xJvmhN/c  
int nCount = input.readInt(); L>NL:68yN  
nStartPos = new long[nCount]; |A9F\A->4  
nEndPos = new long[nCount]; x8\?}UnB  
for(int i=0;i<nStartPos.length;i++) y`5 9A  
{ fLD,5SN  
nStartPos = input.readLong(); ~i{(<.he  
nEndPos = input.readLong(); v2\FA(BPn  
} )Y0!~# `  
input.close(); .x.]`b(  
} ")5":V~fN  
catch(IOException e){e.printStackTrace ();} rgv?gaQ>  
catch(Exception e){e.printStackTrace ();} l -mfFN  
} w"|L:8  
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private void processErrorCode(int nErrorCode) 8.=BaNU  
{ =
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System.err.println("Error Code : " + nErrorCode); q=m'^ ,gPS  
} oj<gD  
$am$EU?s  
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//停止文件下载 wqs?828x  
public void siteStop() Hqx-~hQO  
{ *?>T,gx}  
bStop = true; E\EsWb  
for(int i=0;i<nStartPos.length;i++) u8g~
  
fileSplitterFetch.splitterStop(); v`x.)S1  
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} ({)+3]x  
} fc3{sZE2M  
//负责部分文件的抓取 [;yOBF  
**FileSplitterFetch.java W:nef<WH  
*/ On.{!:"I/  
package NetFox; rJTa  
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import java.io.*; EU;9*W<  
import java.net.*; eHZws`W  
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public class FileSplitterFetch extends Thread {  vF+7V*<  
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vX"*4m>b?+  
String sURL; //File URL uym*a4J  
long nStartPos; //File Snippet Start Position "| g>'wM*  
long nEndPos; //File Snippet End Position 9
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int nThreadID; //Thread's ID At>DjKx]O  
boolean bDownOver = false; //Downing is over vWv"  
boolean bStop = false; //Stop identical T2W eE@o  
FileAccessI fileAccessI = null; //File Access interface $6 9&O  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {9pZ)tB  
{ c_pr  
this.sURL = sURL; UHkMn  
this.nStartPos = nStart; N!=v4f  
this.nEndPos = nEnd; Lv7(st%`  
nThreadID = id; 3M7/?TMw{6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QO~P7r|A  
} uyWunpT  
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public void run() 783,s_  
{ >T-u~i$s  
while(nStartPos < nEndPos && !bStop) *n ]GsOOn  
{ C2I_%nU Z1  
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try{ /Iokf@5  
URL url = new URL(sURL); #q$HQ&k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ()?(I?I
I  
httpConnection.setRequestProperty("User-Agent","NetFox"); n;_sG>N  
String sProperty = "bytes="+nStartPos+"-"; v{N`.~,^  
httpConnection.setRequestProperty("RANGE",sProperty); tSUEZ62EY  
Utility.log(sProperty); 5Ln,{vsv  
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InputStream input = httpConnection.getInputStream(); ?e4YGOe.  
//logResponseHead(httpConnection); -@2iaQ(5a2  
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byte[] b = new byte[1024]; +@f26O7$*  
int nRead; lfgq=8d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Qd{CMmx  
{ ;ef}}K  
nStartPos += fileAccessI.write(b,0,nRead); lrE5^;/s1  
//if(nThreadID == 1) ? :%@vM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ec;o\erPG  
} I$G['`XX/  
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Utility.log("Thread " + nThreadID + " is over!"); z&\a:fJ&  
bDownOver = true; J*A,o~U|  
//nPos = fileAccessI.write (b,0,nRead); |YWD8 +  
} C.-,^+t;g  
catch(Exception e){e.printStackTrace ();} [|$h*YK  
} {S)6;|ua'  
} O=t_yy  
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//打印回应的头信息 T?
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public void logResponseHead(HttpURLConnection con) BDDlQci38  
{ O0v}43J[  
for(int i=1;;i++) F/{!tx  
{ b8t7u  
String header=con.getHeaderFieldKey(i); qe#tj/aZ  
if(header!=null) 0[(8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ? OM!+O  
Utility.log(header+" : "+con.getHeaderField(header)); 1CZgb  
else <'oQ \eB  
break; PC8Q"O  
} (ZZ8L-s  
} >+1duAC  
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public void splitterStop() .`eN8Dl1  
{ h[Y1?ln&h  
bStop = true; K\r8g=U  
} + &Eqk  
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} 2/^3WY1U  
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/* *i%d,w0+  
**FileAccess.java ~36!?&eA8  
*//文件访问(定位，写) d7upz]K9g  
package NetFox; q|(HsLs  
import java.io.*; tyFzSrfc  
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public class FileAccessI implements Serializable{ J ZS:MFA  
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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 oG\Vxg*  
RandomAccessFile oSavedFile; SqpaFWr  
long nPos; ZY+qA  
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public FileAccessI() throws IOException I\ob7X'Xu!  
{ lymCH  
this("",0); NXrlk  
} CD~.z7,LC  
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public FileAccessI(String sName,long nPos) throws IOException a`>B Ly5o  
{ U
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oSavedFile = new RandomAccessFile(sName,"rw"); h2R::/2.  
this.nPos = nPos; #\m<Sz5Gp#  
oSavedFile.seek(nPos); onzxx4bax  
} f+!(k)GWd  
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public synchronized int write(byte[] b,int nStart,int nLen) q_58;Bv  
{ (!WD1w
 
int n = -1; nNn:-  
try{ kffcm/  
oSavedFile.write(b,nStart,nLen); ~]2K^bh8&  
n = nLen; + ePS14G  
} kxv1Hn"`{E  
catch(IOException e) YaqJ,"GlT  
{ 7kEn \
 
e.printStackTrace (); [4f{w%~^  
} 3!]rmZ-W  
> ~O.@|  
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return n; JWxwJex  
} gPPkT"  
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} P&Vv/D  
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/* cvL;3jRo  
**SiteInfoBean.java s~X%Y<9l  
*/ =I_'
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package NetFox; cr;da)  
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public class SiteInfoBean { p`qgrI`  
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private String sSiteURL; //Site's URL BI@[\aRLQ  
private String sFilePath; //Saved File's Path $I?"lky  
private String sFileName; //Saved File's Name >A"(KSNL  
private int nSplitter; //Count of Splited Downloading File pQB."[n  
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public SiteInfoBean() Ny/MJ#Lq  
{//nSplitter的缺省值为5 *vMn$,^0h9  
//default value of nSplitter is 5 )^hbsMhO  
this("","","",5); #RLt^$!H  
} J{G?-+`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _+MJ%'>S
 
{ ]ZS OM\}  
sSiteURL= sURL; mt.))#1  
sFilePath = sPath; Y'X%Aw;`  
sFileName = sName; HGg@ _9tW  
this.nSplitter = nSpiltter; >H,*H;6  
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} _yR^*}xJb  
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public String getSSiteURL() a 1*p*dM#  
{ S+lqA-:  
return sSiteURL; "0TZTa1e  
}
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public void setSSiteURL(String value) BY*8ri^u  
{ #g!.T g'  
sSiteURL = value; alb.g>LNPP  
} TA~{1_l  
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public String getSFilePath() a8Wwq?@  
{ aw>#P   
return sFilePath; _o~nr]zx  
} <OPArht  
<#HYqR',  
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public void setSFilePath(String value) /qw.p#  
{ QS`]  
sFilePath = value; 1h5 Akq  
} vZ Lf  
"
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public String getSFileName() &cTU sK  
{ FVBYo%Ap  
return sFileName; x,Vr=FB  
} hpk7 Anp  
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public void setSFileName(String value) P0b7S'a4!  
{ $ME)#(  
sFileName = value; IE~ |iQ?-  
}
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public int getNSplitter() T
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{ u#SWj,X  
return nSplitter; 3+bt~J0  
} Aiea\jBv  
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public void setNSplitter(int nCount) <54 S  
{ Rx}Gz$
 
nSplitter = nCount; vr^qWn  
} Y nZiTe@  
} %~S&AE-  
t |oR7qa{w  
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/* ;9g2?-svw  
**Utility.java OZ!^ak  
*/ 4E?Oky#}-  
package NetFox; 6LZ;T.0o  
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public class Utility { POR\e|hRT]  
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\nqS+on]  
public Utility()
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{ ?0xgRe<  
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} ~y[7K{{ ;T  
Mb7I[
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//线程睡眠 >-{Hyx  
public static void sleep(int nSecond) <rSF*  
{ ws^ np  
try{ 7J&4akT{9  
Thread.sleep(nSecond); SK
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} p
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catch(Exception e) <b<j=_
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{ GowH]MO  
e.printStackTrace (); [PKR2UEe]  
} dAe')N:KPI  
} H 7 ^/q7  
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//日志 o%*xvH*A  
public static void log(String sMsg) 6\S~P/PkE  
{ Pr,q*_Yy  
System.err.println(sMsg); *HB-QIl  
} #LN`X8Wz'  
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s(roJbJ_;  
public static void log(int sMsg) S`?!G&[!>  
{ 9Lfv^V0  
System.err.println(sMsg); 8e"gW >f  
} /vb`H>P  
} -s'-eQF J  
mlS$>O_aX  
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/* uA#;G/$  
**TestMethod.java {cw /!B  
*/ q6X1P"%.  
package NetFox; #yvGK:F  
eQvg7aO;  
-o EW:~y  
public class TestMethod { 5QO9Q]I#_\  
~.lPEA %%  
_oDz-  
public TestMethod() vgN&K@hJ  
{ ///xx/weblogic60b2_win.exe @!d{bQd,  
try{  1ZB"EQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _8agtQ:<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :S(ZzY Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "G9xM
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fileFetch.start(); ?#Q #u|~  
} F^fdIZx  
catch(Exception e){e.printStackTrace ();} 2T[9f;jM'  
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} &XU
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Yp2eBgo"  
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public static void main(String[] args) {P#|zp4C{  
{ &Z|P2dI  
new TestMethod(); VTHH&$ZNq  
} -1ub^f
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} n>U5R_T  
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