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http断点续传简单实现(java)

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/* |~Awm"  
**SiteFileFetch.java %74f6\  
*/ +tlbO?  
package NetFox; nu|?F\o!  
import java.io.*; *:l$ud  
import java.net.*; HW6Cz>WxOW  
8,CL>*A  
}ZwnG=7T?  
public class SiteFileFetch extends Thread { &t@ $]m(  
eEmLl(Lb  
jNIz:_c-~  
SiteInfoBean siteInfoBean = null; //文件信息Bean !P6y_Frpe  
long[] nStartPos; //开始位置 ri9n.-xs  
long[] nEndPos; //结束位置 1Ji"z>H*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 at3YL[,[Z  
long nFileLength; //文件长度 #TP Y%  
boolean bFirst = true; //是否第一次取文件 Uzn  
boolean bStop = false; //停止标志 eLyIQoW  
File tmpFile; //文件下载的临时信息 .lc gM  
DataOutputStream output; //输出到文件的输出流 jd+HIR  
!wrAD"l*@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) x||b :2  
public SiteFileFetch(SiteInfoBean bean) throws IOException lnxA/[`a  
{ Oo\~' I  
siteInfoBean = bean; @zix %x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sg]g;U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @[rlwwG,  
if(tmpFile.exists ()) r7)iNTQ1  
{ E?m W4?  
bFirst = false; .e:+Ek+  
read_nPos(); 0wETv  
} 8,m:  
else .B$3y#TOb  
{ Ujly\ix`  
nStartPos = new long[bean.getNSplitter()]; =4x-x nA  
nEndPos = new long[bean.getNSplitter()]; LGCeYXic  
} %ZlnGr  
j!"NEh78H  
5_L43-  
Rn whkb&&  
} y+VR D  
~-(X\:z}  
;Y &2G'  
public void run() C2%Yry  
{ _..5G7%#%  
//获得文件长度 l?beqw:  
//分割文件 k .F(*kh  
//实例FileSplitterFetch IZ_ B $mo  
//启动FileSplitterFetch线程 {O[ !*+O  
//等待子线程返回 1`n ZK$  
try{ A5dH*< }  
if(bFirst) gm&O-N"= U  
{ iB'g7&,L  
nFileLength = getFileSize(); O{G $]FtF  
if(nFileLength == -1) Fg^zz*e  
{ [  **F  
System.err.println("File Length is not known!"); L\kT9wWK|  
} w?p8)Q6m  
else if(nFileLength == -2) R2[ }  
{ CwfGp[|}e  
System.err.println("File is not access!"); nx4E}8!Lh  
} t== a(e  
else RQ51xTOL4]  
{ <=~'Pd-f(  
for(int i=0;i<nStartPos.length;i++) 5z:/d`P[  
{ %gx>|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Hkj| e6  
} O`(it %Ho!  
for(int i=0;i<nEndPos.length-1;i++) f]^ @z<FC  
{ $Jj0%?;  
nEndPos = nStartPos[i+1]; T b]'  b  
} SB!m&;Tb  
nEndPos[nEndPos.length-1] = nFileLength; C)s*1@af  
} :20k6)  
} v{>9&o.J  
v]KI=!Gs  
y/A<eHLy  
//启动子线程 @Cd}1OT)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }A_>J7w  
for(int i=0;i<nStartPos.length;i++) ~f%AbDye  
{ t!vlZNc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o)6udRzBv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8"S? Toqq  
nStartPos,nEndPos,i); \U'TL_Ql  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5'O.l$)y  
fileSplitterFetch.start(); 7llEB*dSA  
} iJK rNRj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4K*DEVS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]z/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s((_^yf  
nEndPos = " + nFileLength); ?GGh )";y  
// fileSplitterFetch[nPos.length-1].start(); @-qC".CI  
()i!Uo  
QJ-?6 7_i  
//等待子线程结束 EC| b7  
//int count = 0; Z})n%l8J]p  
//是否结束while循环 5B=Wnau  
boolean breakWhile = false; 6MR S0{  
./;*L D  
-Qco4>Z8  
while(!bStop) -?<L"u  
{ 5Bc)QKh`l|  
write_nPos(); ? &;d)TQ  
Utility.sleep(500); /%GMbO_  
breakWhile = true; OL"So u4  
KbV%8nx!!  
zoBjrAyD  
for(int i=0;i<nStartPos.length;i++) y7s.6i}7  
{ Y:="vWWG  
if(!fileSplitterFetch.bDownOver) cM'5m  
{ =8fZG t  
breakWhile = false; dQL! >6a  
break; OG}D;Ew  
} ;w}5:3+  
} w]0jq U6  
if(breakWhile) DWH)<\?  
break; Uyyw'Ni  
Kq0hT4w  
J#W>%2 "s  
//count++; &hYjQ&n  
//if(count>4) jNNl5.  
// siteStop(); t| zLR  
} @V-CG!  
&_E*]Sj\  
W\<5'9LNb  
System.err.println("文件下载结束!"); HCifO  
} ,Pd2ZfZ  
catch(Exception e){e.printStackTrace ();}  0-+`{j  
} Vkb&' rXw+  
pf`li]j'V  
2={ g'k(  
//获得文件长度 uQ.VW/>  
public long getFileSize() BPd]L=,/  
{ MY[" zv  
int nFileLength = -1; 8)k.lPoo.  
try{ w,.Hdd6  
URL url = new URL(siteInfoBean.getSSiteURL()); , 0rC_)&B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :+,qvu!M7  
httpConnection.setRequestProperty("User-Agent","NetFox"); %tzz3Y  
K`2a{`  
?Xo9,4V1  
int responseCode=httpConnection.getResponseCode(); vu.f B4  
if(responseCode>=400) Ic/<jFZXM  
{ !<2*B^   
processErrorCode(responseCode); ':w6 {b  
return -2; //-2 represent access is error 2h6F j&  
} zj;y`ENj  
F<w/@ .&m  
;SVF"Uo  
String sHeader; i9M6%R1m}E  
Ve8`5  
[P{Xg:0  
for(int i=1;;i++) z[ ;{p.W  
{  . yu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LVLh&9  
//Utility.log(in.readLine()); Urx gKTry  
sHeader=httpConnection.getHeaderFieldKey(i); &/, BFx"  
if(sHeader!=null) cY>;(x@  
{ Ec6{?\  
if(sHeader.equals("Content-Length")) %3VwCuE  
{ }%R6Su]y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xt"/e-h }  
break; ]@ [=FK^  
} }wkBa]  
} <ZrZSt+<  
else W^+b gg<.  
break; =8dCk\/  
} R4JO)<'K&  
} l>&)_:\  
catch(IOException e){e.printStackTrace ();} {YbqB6zaM  
catch(Exception e){e.printStackTrace ();} M3F8@|2  
a<gzI  
 (lPNMS|V  
Utility.log(nFileLength); 9 au)K!hN  
s_Dl8O4u  
Wu Gm~<NS  
return nFileLength; #G{T(0<F  
} 6U+#ADo  
>uJrq""+  
c*1x*'j.  
//保存下载信息(文件指针位置) ?I/,r2ODLh  
private void write_nPos() SKfv.9  
{ iKS9Xss8  
try{ 6OTxtk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #lLL5ji  
output.writeInt(nStartPos.length); Da@tpKU)p  
for(int i=0;i<nStartPos.length;i++) LL6f40hC  
{ esu6iU@  
// output.writeLong(nPos); WD?V1:>+  
output.writeLong(fileSplitterFetch.nStartPos); 7\/O"Ot  
output.writeLong(fileSplitterFetch.nEndPos); yMSRUQ x  
} dF.T6b  
output.close(); zPkg3H  
} !s)$_tG  
catch(IOException e){e.printStackTrace ();} 329xo03-[  
catch(Exception e){e.printStackTrace ();} Yu1xJgl  
} :6M0`V;L  
Y]gt86  
*,n7&  
//读取保存的下载信息(文件指针位置) cq9Q7<&MF  
private void read_nPos() ^3yjE/Wi"  
{ wA~Nfn ^  
try{ w\2[dd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r 2H'r ,N  
int nCount = input.readInt(); rP\ 7C+  
nStartPos = new long[nCount]; <0LB]zDWe6  
nEndPos = new long[nCount]; wFd*6%  
for(int i=0;i<nStartPos.length;i++) 4rzioIk  
{ 462ae` 6l  
nStartPos = input.readLong(); *r% mqAx(  
nEndPos = input.readLong(); <m6I)}K  
} p$%h!.~99T  
input.close(); }.gg!V'9w  
} u('OHPqq  
catch(IOException e){e.printStackTrace ();} 0'~b<>G%  
catch(Exception e){e.printStackTrace ();} bA^a@ lv a  
} z vYDE]  
n `Xz<Q!  
T i/iD2g  
private void processErrorCode(int nErrorCode) (7wR*vO^  
{ |(H|2]b4 =  
System.err.println("Error Code : " + nErrorCode); q-3KF  
} <|`@K| N  
RYhdf  
BxT~1SBFq  
//停止文件下载 N7jRdT2k%  
public void siteStop() CM#EA"9  
{ 88*RlxU  
bStop = true; d!LV@</  
for(int i=0;i<nStartPos.length;i++) <V8i>LBlz  
fileSplitterFetch.splitterStop(); &sNID4FR  
aw4+1.xy  
T8(wzs  
} ^+wzm2i  
} t/D Q<B_  
//负责部分文件的抓取 1*jL2P]D  
**FileSplitterFetch.java :hr@>Y~r  
*/ 7cy~qg  
package NetFox; xXYens}  
AP7W)S  
R`?^%1^N  
import java.io.*; 6;b 'j\jG  
import java.net.*; Uy1xNb/d  
C/vLEpP{(/  
jlP7'xt1%  
public class FileSplitterFetch extends Thread { ,q HG1#^  
).S<{zm7  
9]w0zUOL6  
String sURL; //File URL ^U?(g0<"  
long nStartPos; //File Snippet Start Position 9M=K@a  
long nEndPos; //File Snippet End Position c\'pA^m 6  
int nThreadID; //Thread's ID ri;M7rg`.{  
boolean bDownOver = false; //Downing is over Zs{R O  
boolean bStop = false; //Stop identical Tz-cN  
FileAccessI fileAccessI = null; //File Access interface iQIw]*h^  
B<&_lG0sS  
,+BgY4OY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException / IS WC   
{ oQXkMKZ  
this.sURL = sURL; wE \c?*k  
this.nStartPos = nStart;  e C{Z  
this.nEndPos = nEnd; JT9<kB/07  
nThreadID = id; KEN-G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -]A#G`'  
} .%<&W1  
#G=QL(f>/  
|*NrS<"  
public void run() %Eh%mMb^  
{ u_"h/)C'H  
while(nStartPos < nEndPos && !bStop) -YyH"f   
{ 4w6K|v<X  
Y fA\#N0;3  
X&~Eo  
try{ R"o,m  
URL url = new URL(sURL); NXNon*"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b . j^US^  
httpConnection.setRequestProperty("User-Agent","NetFox"); HXHPz 4  
String sProperty = "bytes="+nStartPos+"-"; =k7\g /  
httpConnection.setRequestProperty("RANGE",sProperty); $?-o  
Utility.log(sProperty); zn!  
49$4  
K@~#Gdnl  
InputStream input = httpConnection.getInputStream(); }x1IFTa!  
//logResponseHead(httpConnection); /xbZC{R  
I yN9 +  
Y]K]]Ehp  
byte[] b = new byte[1024]; CEq]B:[IC  
int nRead; 0Ida]H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d@4!^vD;  
{ #jx?uS  
nStartPos += fileAccessI.write(b,0,nRead); -b}S3<15@  
//if(nThreadID == 1) X4G55]D$>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 05 Q8`  
} y;Ln ao7i  
 ?|J+dW  
~&3"Mi&>`  
Utility.log("Thread " + nThreadID + " is over!"); 8#u_+;,p  
bDownOver = true; U3K<@r  
//nPos = fileAccessI.write (b,0,nRead); h}>/Z3*  
} =hOa 0X=  
catch(Exception e){e.printStackTrace ();} ] *VF Ws  
} 3a}`xCO5  
} mZVOf~9E  
51ebE`  
U(=9&c@]  
//打印回应的头信息 PjW+V`  
public void logResponseHead(HttpURLConnection con) c\{}FGC  
{ C'2 =0oou  
for(int i=1;;i++) Pq>[q?>?  
{ I 47GQho  
String header=con.getHeaderFieldKey(i); g Pj0H&,.  
if(header!=null) hr6e1Er  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (zDk68=v  
Utility.log(header+" : "+con.getHeaderField(header)); Su$1 t  
else [(F<|f:n  
break; dd7nO :]  
} F'$S!K58  
} $jh>zf  
)9*3^v  
EJ ~k Z3  
public void splitterStop() Q9xx/tUW  
{ )$h9Y   
bStop = true; XJ~l5} y ]  
} 3t{leuO'  
lO:{tV  
&N_c-@2O  
} K!c@aD:#  
eu]iwOc&p  
' VEr4&  
/* kz;_f  
**FileAccess.java `N.$LY;8  
*//文件访问(定位,写) eoe^t:5&  
package NetFox; Qr%Jm{_o  
import java.io.*; >[fVl 8G_0  
UdW(\%  
y*b.eO  
public class FileAccessI implements Serializable{ dX@A%6#?  
q[OTaSQ~u^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .7gE^  
RandomAccessFile oSavedFile; Qb't*2c%  
long nPos; r82o[+$u0K  
o $`kpr  
UnWGMo?JEi  
public FileAccessI() throws IOException J1p75c%  
{ +aw>p_\  
this("",0); 5J+V:Xu{  
} ?5v5:U(A  
{I-a;XBX  
k gu[!hD1  
public FileAccessI(String sName,long nPos) throws IOException nlebFDb7  
{ (5q%0|RzRs  
oSavedFile = new RandomAccessFile(sName,"rw"); RYZE*lWUh  
this.nPos = nPos; ]( =wlq)  
oSavedFile.seek(nPos); qm}>J^hnB#  
} s >VEuLY*  
Sj{ia2AE_  
rt^45~  
public synchronized int write(byte[] b,int nStart,int nLen) {rvbo1t  
{ t0J5v;  
int n = -1; LJ(n?/z%  
try{ /uE^H%9h  
oSavedFile.write(b,nStart,nLen); [)SR $/A  
n = nLen; ^[,s_34V  
} ~x4B/zW?  
catch(IOException e) oCKM5AVWsv  
{ fQ36Hd?(5  
e.printStackTrace (); <@e+-$  
} |[37:m  
p + l_MB  
C. Ja;RFq  
return n; O GFE*  
} ~` \9Q  
xe6_RO%  
%+xwk=%*  
} zzfn0g  
80$0zbw$  
&6t3SZV  
/* a}Fk x  
**SiteInfoBean.java Sc'c$/  
*/ pH\^1xj =  
package NetFox; zd9]qo  
inBPT~y  
&=-e`=qJ'6  
public class SiteInfoBean { ]`@]<6  
*F szGn<  
r6n5Jz  
private String sSiteURL; //Site's URL "@{4.v^}!  
private String sFilePath; //Saved File's Path /:y2Up-  
private String sFileName; //Saved File's Name pYfV~Q^3  
private int nSplitter; //Count of Splited Downloading File IypWVr   
Vj=Xcn#*8  
3@yTzaq6  
public SiteInfoBean() W ~Jzqp9g  
{//nSplitter的缺省值为5 i$bzdc#s  
//default value of nSplitter is 5 ]<q}WjXD'  
this("","","",5); G*(K UG>  
} *t.q m5h  
whY~=lizn  
|}M0,AS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SH vaV[C  
{ ;vJ\]T ml  
sSiteURL= sURL; _V& !4Zd9:  
sFilePath = sPath; {Vxc6,=  
sFileName = sName; &"[)s[m+t  
this.nSplitter = nSpiltter; Ak6MPuBB-  
+mc [S  
?Q96,T-) c  
} PEW4J{(W  
>I4p9y(u  
^XBzZ!h|  
public String getSSiteURL() 4bi NGl~  
{ zj>aaY  
return sSiteURL; q]eFd6  
} [0&'cu>  
F!gNt<fZ  
Dn_"B0$lk  
public void setSSiteURL(String value) 2~!R*i  
{ dI^IK  
sSiteURL = value; 6 u-$  
} /mn-+u`K  
SOp=~z  
}!%JYG^!D  
public String getSFilePath() 2mqK3-c  
{ #ya\Jdx   
return sFilePath; DH:GI1Yu>I  
} GIm " )}W  
1~2R^#rm  
jg [H}  
public void setSFilePath(String value) }bf=Ntk  
{ 22`oFXb'  
sFilePath = value; bmOqeUgB  
} 5@`F.F>"  
y=AsgJ  
%MJL5  
public String getSFileName() <4bz/^  
{ =)I"wR"v$  
return sFileName; E6Q]A~  
} A8pj~I/*-  
:dP~.ZY7  
SY-ez 91  
public void setSFileName(String value) l{Jt sI  
{ $Y6I_U  
sFileName = value; 8Q2]*%  
} T><{ze  
5@P%iBA4(3  
jn-QKdqM  
public int getNSplitter() d^F|lc ]8  
{ J["H[T*  
return nSplitter; 0"EoC  
} . yZm^&  
QsiJ%O Q  
Q}kfM^i  
public void setNSplitter(int nCount) ~U6" ?  
{ VeZey)Q  
nSplitter = nCount; OAv>g pw  
} iF!mV5#  
} Sd},_Kh  
/X4yB"J>  
zfhTc=(/  
/* .K IVf8)"  
**Utility.java N.Dhu~V  
*/ *E:x E/M!2  
package NetFox; qmZ2d!)o  
o+nG3kRD  
xXX/]x>  
public class Utility { ><;Q@u5~  
kt^yj"C>  
NYBe"/}GS  
public Utility() KOjluP  
{ R A:jzht  
![ZmV  
57~Uqt  
} nV}8M  
(}Sr08m  
//线程睡眠 >$\Bu]{1  
public static void sleep(int nSecond) Sp:l;SGd  
{ WsR+Np@c  
try{ 4qhWm"&CM  
Thread.sleep(nSecond); 5[C~wvO  
} $>*Yhz `  
catch(Exception e) rH&G<o&,  
{ aD9rp V  
e.printStackTrace (); 79ckLd9  
} Sk:2+inU  
} $;2)s} ci  
Cq>6rn  
//日志 P z ?m>>#  
public static void log(String sMsg) 38~PWKt  
{ %}q .cV  
System.err.println(sMsg); @6 /yu>%  
} jd 1jG2=f  
G"T\=cQz  
uWjN2#&,  
public static void log(int sMsg) fc@'9- pt  
{ $X \va?(  
System.err.println(sMsg); ;+ azeW ^  
} 0VN7/=n|  
} ,_jC$  
@x1 %)1  
!Xj#@e  
/* qI%&ay"/  
**TestMethod.java  G2`${aMS  
*/ hQRL,?  
package NetFox; vE%s, E,  
~6`iY@)  
*5k+t  
public class TestMethod { wv?RO*E  
BcQEG *N  
E{4 e<%Y,  
public TestMethod() gbDX7r-  
{ ///xx/weblogic60b2_win.exe m:uPEpcU  
try{ +dk f cG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9sSN<7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); f'X9HU{Cz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~`qEWvPn  
fileFetch.start(); mT @ nn,  
} n[,XU|2  
catch(Exception e){e.printStackTrace ();} e_.Gw"/Yl  
:^i^0dC  
p[9s<lEh  
} |mhKIis U  
eQUe >*  
+5!&E7bcd  
public static void main(String[] args) `!vUsM.d  
{ |4;UyHh  
new TestMethod(); u.,Q4u|!  
} .@#A|fgv  
} 6cz/n8Mg  
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