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http断点续传简单实现(java)

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/* nMVThN*I g  
**SiteFileFetch.java Jw {:1  
*/ MgtyO3GUAD  
package NetFox; &V$'{  
import java.io.*; R9=,T0Y p  
import java.net.*; jv_sRV  
xR1g  
09x\i/nb  
public class SiteFileFetch extends Thread { 5l)p5Bb48c  
ih~c(&n0  
-F5U.6~`!  
SiteInfoBean siteInfoBean = null; //文件信息Bean  ) mv}u~  
long[] nStartPos; //开始位置 lbv, jS  
long[] nEndPos; //结束位置 k?xtZ,n{s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Bpk%,*$*)  
long nFileLength; //文件长度 _B W$?:)9  
boolean bFirst = true; //是否第一次取文件 MX9 q )(:  
boolean bStop = false; //停止标志 * =;=VUu5  
File tmpFile; //文件下载的临时信息 OpH9sBnA  
DataOutputStream output; //输出到文件的输出流 W%1fm/ G0  
d,D)>Y'h  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Wg}#{[4  
public SiteFileFetch(SiteInfoBean bean) throws IOException eMh:T@SN  
{ cwpDad[Kx  
siteInfoBean = bean; KCCS7l/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D=dY4WwG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $X\BO&  
if(tmpFile.exists ()) Ke 'bH  
{ C2Y&qX,  
bFirst = false; Wm3H6o*  
read_nPos(); {z.}u5N  
} 4 6e;UUf!d  
else q2/Vt0aYx  
{ SULWPH5Pr  
nStartPos = new long[bean.getNSplitter()]; ]pB~&0jg  
nEndPos = new long[bean.getNSplitter()]; *><] [|Y@H  
} PK+][.6H  
9:=a FP  
PfuYT_p4s  
0tsll1  
} W}.4$f>  
_fa]2I  
CZ&TUE|:DA  
public void run() h+$_:](PC  
{ ;'<K}h  
//获得文件长度 #lct"8  
//分割文件 SH`"o  
//实例FileSplitterFetch <&+l;z  
//启动FileSplitterFetch线程 Y[x ^59  
//等待子线程返回 crhck'?0  
try{ F;~ #\ X  
if(bFirst) JL(*peeu3  
{ {1SxM /  
nFileLength = getFileSize();  j, G/[V  
if(nFileLength == -1) YJ75dXc&&  
{ ueWG/`ig  
System.err.println("File Length is not known!"); %[p[F~Z^Z  
} c6lEWC:  
else if(nFileLength == -2) kbMIMZC/G  
{ gE$dz#t.  
System.err.println("File is not access!"); L>@6lhD)x  
} 3\'.1p  
else h hd n9n  
{ |Ec$%  
for(int i=0;i<nStartPos.length;i++) ipbVQ7  
{ [C d 2L&9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U9N}6a=  
} %NAz(B  
for(int i=0;i<nEndPos.length-1;i++) @Sv  ?Ar  
{ :'rXu6c-  
nEndPos = nStartPos[i+1]; o oS4F1ta  
} ' !_44  
nEndPos[nEndPos.length-1] = nFileLength; U}qW9X;o  
} M_XZOlW5  
} !-;Me&"I=`  
h.7 1O"N  
MA1,;pv6  
//启动子线程 8a05`ZdP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \<PX'mnO  
for(int i=0;i<nStartPos.length;i++) @D60  
{ 'wQ=b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sJ0y3)PQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), # =322bnO  
nStartPos,nEndPos,i); zD?$O7 |ZK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }7C{:H2d  
fileSplitterFetch.start(); zg5 u  
} riBT5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y.hrU*[J0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +"p" ,Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]XP[tLY Y  
nEndPos = " + nFileLength); L4[ bm[x  
// fileSplitterFetch[nPos.length-1].start(); {{ wVM:1  
MK"Yt<e(o  
Y{J/Oib  
//等待子线程结束 "1[N;|xa  
//int count = 0; ga,yFw  
//是否结束while循环 +HfjnEbtBs  
boolean breakWhile = false; ]T*{M  
\ _i`=dx  
(JM4W "7'  
while(!bStop) 6dinC <[}  
{ E?FPxs  
write_nPos(); @*c+`5)_  
Utility.sleep(500); x[>A'.m@)  
breakWhile = true; e EU :  
Q% dpGI  
RL&*.r&  
for(int i=0;i<nStartPos.length;i++) KlrKGmy,)  
{ N.&K"J  
if(!fileSplitterFetch.bDownOver) w1GCjD*y  
{ iYnw?4Y  
breakWhile = false; Y&&Y:+ V  
break; ! 4s $ 93  
} \XpPb{:>  
} {$s:N&5  
if(breakWhile) r] ]Ke_s!  
break; ~q1s4^J  
@L~y%#  
'17=1\Ss6;  
//count++; ~pF'Qw" z|  
//if(count>4) o+tY[UX  
// siteStop(); [@\f 0R  
} OsK=% aDpj  
h`vM+,I  
*wSl~J|ZM%  
System.err.println("文件下载结束!"); y'+^ ME$H  
} jf%Ydr}`  
catch(Exception e){e.printStackTrace ();} k5ZwGJ#r  
} =W4cWG?+  
d[S!e`,iD  
^X_%e|  
//获得文件长度 W&*{j;e9%I  
public long getFileSize() t4JGd)r  
{ J,q:  
int nFileLength = -1; pr m  
try{ ^L'K?o  
URL url = new URL(siteInfoBean.getSSiteURL()); - jyD!(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nh+$'6yT%  
httpConnection.setRequestProperty("User-Agent","NetFox"); b ;}MA7=  
t7~mW$}O  
nY*ODL  
int responseCode=httpConnection.getResponseCode(); +(P;4ZOmB  
if(responseCode>=400) V3`*LU  
{ "Srp/g]a  
processErrorCode(responseCode); N7M^  
return -2; //-2 represent access is error )q=1<V44d  
} JRo{z{!O6  
V,Gt5lL&/!  
aI\VqOt]  
String sHeader; -I|yi'  
2N]y)S_<V  
Ny~;"n  
for(int i=1;;i++) TQEZ<B$  
{ kNjbpCE\!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }5]NUxQ_  
//Utility.log(in.readLine()); *i n_Z t3  
sHeader=httpConnection.getHeaderFieldKey(i); `#(4K4]1.  
if(sHeader!=null) l,/5$JGnk  
{ $@U`zy"Y  
if(sHeader.equals("Content-Length")) tl4;2m3w  
{ SMhT>dB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nBD7  
break; 2?"9NQvz  
} G?"1 z;  
} x7*}4>|W,I  
else \fKv+  
break; SKS[Lf  
} F0|T%!FB>%  
} '2 )d9_ w  
catch(IOException e){e.printStackTrace ();} c^=:]^  
catch(Exception e){e.printStackTrace ();} 1XZ&X]  
-p)HH@6a  
NT-du$! u  
Utility.log(nFileLength); pG4Hy$e  
! [:K/  
OC [a?#R1  
return nFileLength; HKh)T$IZM  
} pkT a^I  
i@p?.%K{  
d5i /:  
//保存下载信息(文件指针位置) i'57|;?  
private void write_nPos() F^w0TD8  
{ Z2`e*c-[E  
try{ MJD4#G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NH?s  
output.writeInt(nStartPos.length); :Ert57@l  
for(int i=0;i<nStartPos.length;i++) <iMkHch  
{ {<_}[} XY  
// output.writeLong(nPos); I{2e0  
output.writeLong(fileSplitterFetch.nStartPos); zJV4)  
output.writeLong(fileSplitterFetch.nEndPos); ~<$8i}7  
} G)putk@   
output.close(); B]hZ4.B1  
} '6aH*B:}*;  
catch(IOException e){e.printStackTrace ();} 8^~ljf]6  
catch(Exception e){e.printStackTrace ();} l >O]Cpt  
} ybB}|4d&   
Z>{8FzP.F  
cg$~.ytPK  
//读取保存的下载信息(文件指针位置) C {'c_wX  
private void read_nPos() !^N/n5eoz  
{ !#X^nlc  
try{ 6^wiEnA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C :e 'wmA  
int nCount = input.readInt(); 2z-&Ya Qu  
nStartPos = new long[nCount]; YGNX+6Lz  
nEndPos = new long[nCount]; zxj!ihs<  
for(int i=0;i<nStartPos.length;i++) &,#VhT![  
{ P "%/  
nStartPos = input.readLong(); [oYe/<3  
nEndPos = input.readLong(); \myj Y  
}  KL|B| u  
input.close(); ?hwQY}   
} ) wGC=,  
catch(IOException e){e.printStackTrace ();} q|j;dI&  
catch(Exception e){e.printStackTrace ();} @!F9}n AP  
} 7N""w5  
NeWssSje  
q=EQDHmh  
private void processErrorCode(int nErrorCode) /bw-*  
{ S-L6KA{  
System.err.println("Error Code : " + nErrorCode); hQk mB|];5  
} ";zl6g"  
*JDc1$H0  
2/bck)p=  
//停止文件下载 U M#]olh  
public void siteStop() B(>_.x#kv  
{ AUN Tc3  
bStop = true; F:H76O`8  
for(int i=0;i<nStartPos.length;i++) p@^2 .O+  
fileSplitterFetch.splitterStop(); Y /w vn8~C  
jRBx7|ON  
QzS{2Y[OQ  
} co*5NM^  
} 5 Fd]3  
//负责部分文件的抓取 k%LE"Q  
**FileSplitterFetch.java ?r@ZTuq#  
*/ mhs%b4'>  
package NetFox; T^Z#x-Q  
!KF;Z|_(I  
- Zw"o>  
import java.io.*; N[mOJa:  
import java.net.*; F4PD3E_#  
z=u4&x|xA  
M0]fh5O  
public class FileSplitterFetch extends Thread { 11)~!in  
ht=yzJ9Pr  
=6 [!'K  
String sURL; //File URL )XNcy"   
long nStartPos; //File Snippet Start Position bM!`C|,[s  
long nEndPos; //File Snippet End Position |l ~ADEg  
int nThreadID; //Thread's ID !O.B,  
boolean bDownOver = false; //Downing is over Q/+a{m0 f  
boolean bStop = false; //Stop identical w"Z >F]YZ  
FileAccessI fileAccessI = null; //File Access interface Uligr_c?  
pu^1s#g8w  
-ss2X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Wd%j;glG  
{ 4@VX%5uy  
this.sURL = sURL; kz??""G7/  
this.nStartPos = nStart; bb<Vh2b>R  
this.nEndPos = nEnd; T<ua0;7  
nThreadID = id; y"]> Rr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U%#=d@?  
} (z.Vwl5  
G9gvOEI/  
Ex Qld  
public void run() c.XLEjV|  
{ @e slF  
while(nStartPos < nEndPos && !bStop) I4)vJ0  
{ Obd!  
`W/6xm(X5;  
'|+_~ZO*d  
try{ =GpLlJ`-  
URL url = new URL(sURL); PK~okz4b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EYQ!ELuF  
httpConnection.setRequestProperty("User-Agent","NetFox"); mEqV&M1;7l  
String sProperty = "bytes="+nStartPos+"-"; dxd}:L~z  
httpConnection.setRequestProperty("RANGE",sProperty); y3xP~]n  
Utility.log(sProperty); xq]&XlA:ug  
Z BYmAD  
j9,X.?Xvx  
InputStream input = httpConnection.getInputStream(); |)lo<}{  
//logResponseHead(httpConnection); Tu"yoF  
m760K*:i\  
T&h|sa(   
byte[] b = new byte[1024]; 'R$~U?i8  
int nRead; 0q3 :"X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jVA xa|S  
{ <ImeZ'L7  
nStartPos += fileAccessI.write(b,0,nRead); qzG'Gz{{qu  
//if(nThreadID == 1) :')<|(Zy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D?E5p.!A  
} Wl,yznT  
k82'gJ;MC=  
8=e \^Q+  
Utility.log("Thread " + nThreadID + " is over!"); ?@XO*|xkSk  
bDownOver = true; *7Mrng  
//nPos = fileAccessI.write (b,0,nRead); F%Xq}LMd  
} (O&b:D/Y  
catch(Exception e){e.printStackTrace ();} ;uJVY)7a  
} \GkcK$Y  
} ;Rt,"W)  
9f V57  
N0XGW_f  
//打印回应的头信息 XR+2|o  
public void logResponseHead(HttpURLConnection con) 9*x9sfCv9  
{ &Y,Rm78  
for(int i=1;;i++) X$xqu\t7  
{ "47nc1T+n  
String header=con.getHeaderFieldKey(i); 8=?I/9Xh  
if(header!=null) -8TLnl~[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Di L@NU!$q  
Utility.log(header+" : "+con.getHeaderField(header)); @tP,l$O&  
else C2VZE~U+  
break; 59)PJ0E  
} ik]UzB  
} sI.Ezuw  
[~;9Mi.XL  
c2y5[L7?  
public void splitterStop() KSexG:Xb  
{ +Gjy%JFp  
bStop = true; ](O!6_'d  
} 5-sxTp  
F!Uk`[L  
Q[k}_1sWs$  
} 2qEy"DKu  
:xA'X+d/'  
l^SKd  
/* AKHi$Bk  
**FileAccess.java `fL$t0 "  
*//文件访问(定位,写) ,,6e }o6  
package NetFox; 2#rF/!`^  
import java.io.*; @-W)(9kZ|  
1p tPey  
.|rpj&>g  
public class FileAccessI implements Serializable{ i#eb%9Mn  
!]"T`^5,Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VJPt/Dy{  
RandomAccessFile oSavedFile; }6o` in>M  
long nPos; Bp b_y;E  
\ET7  
N (43+  
public FileAccessI() throws IOException $V@IRBm  
{ u6D>^qF}@'  
this("",0); +4@EJRC  
} }?H|9OS  
\oaO7w,:"  
:lcoSJ  
public FileAccessI(String sName,long nPos) throws IOException y0z}[hZ  
{ k<AnTboa  
oSavedFile = new RandomAccessFile(sName,"rw"); UGAP$_j ]P  
this.nPos = nPos; v_b%2;<1  
oSavedFile.seek(nPos); O8M;q!)y  
} X)'uTf0  
<Nkj)`%5iK  
;]'mx  
public synchronized int write(byte[] b,int nStart,int nLen) p-;*K(#X  
{ 0(64}T)  
int n = -1; WJl&Vyl2FL  
try{ ]r|X[9  
oSavedFile.write(b,nStart,nLen); qi$6y?  
n = nLen; /5SBLp}Sy  
} uN'e~X6  
catch(IOException e) @ UX'(W  
{ cE[4CCpy  
e.printStackTrace (); O,hT< s "  
} mhVSZhx|  
zs WYV n]  
Fd0R?d  
return n; Z?dz@d%C  
} Ia[e 7  
JZ9w!)U  
@/7tN3O  
} (Y:5u}*Y  
r 5:DIA!  
QYDSE  
/* K oo%mr   
**SiteInfoBean.java L_Ff*   
*/ &pV'/  
package NetFox; r. :LZEr  
A-qdTJP  
' 4ftclzL  
public class SiteInfoBean { H W)> `  
3D(/k%;)  
>6KuZ_  
private String sSiteURL; //Site's URL zXIVHC,"{  
private String sFilePath; //Saved File's Path X=8y$Yy  
private String sFileName; //Saved File's Name >2tYw,m  
private int nSplitter; //Count of Splited Downloading File VMZ\9IwI  
( hp 52Vse  
!Qy%sY  
public SiteInfoBean() r ".*l?=  
{//nSplitter的缺省值为5 pxDkf|*   
//default value of nSplitter is 5 >;LXy  
this("","","",5); K)QM xn  
} scT,yNV  
W9+H /T7!  
p D-k<8|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \oA>%+]5  
{ 8KiG(6*Q  
sSiteURL= sURL; Cjc>0)f&.  
sFilePath = sPath; .nl!KzO6g  
sFileName = sName; Arc6d5Q  
this.nSplitter = nSpiltter; >k }ea5+  
?0*,x)t  
OX-t#R`  
} r~nD%H:}P  
g 0O~5.f  
Pq u]?X  
public String getSSiteURL() n@[_lNa4GD  
{ Vsw] v  
return sSiteURL; e ?sMOBPlv  
} ^hiIMqY_{`  
jlXzfD T  
1cq"H/N  
public void setSSiteURL(String value) & 6 wD  
{ <hkSbJF  
sSiteURL = value; g\%;b3"#  
} =S+*= jA  
oN({X/P2j  
_@2}zT  
public String getSFilePath() *hWpJEV  
{ UI2TW)^2  
return sFilePath; WVZ](D8Gc]  
} GBeWF-`B  
2S,N9 (7  
5ir Ffr  
public void setSFilePath(String value) K-,4eq!  
{ zbY2gq@?  
sFilePath = value; fab. %$  
} 3']a1\sy^  
qtrN=c3x  
00SYNG!  
public String getSFileName() ]w,:T/Z}  
{ r+:]lO  
return sFileName; "%peYNZ&%  
} f4 k  
H2kib4^i  
A4uKE"WE  
public void setSFileName(String value) b!p]\B!  
{ 4t 5i9+h  
sFileName = value; Nwwn #+  
} YuXCRw9p;  
)d~{gPr.  
t| PQ4g<  
public int getNSplitter() q]scKWYI  
{ jlxY|;gZ-0  
return nSplitter; W{RZ@ 3ZY  
} ]J1oY]2~  
!MXn&&e1  
whi#\>i  
public void setNSplitter(int nCount) mO=A50_&,Q  
{ Z)&!ZlM  
nSplitter = nCount; s5/u>d  
} !n7'TM '  
} hv0bs8h  
Wu~cy}\  
&t~NR$@  
/* $-)T  
**Utility.java **V8a-@  
*/ dAWB.#  
package NetFox; ;9CbioO  
m#Ydq(0+  
<78*-Ob  
public class Utility { S,Z~-j  
{^D; ($lm  
=,b6yV+$D  
public Utility() J@o_-\@  
{ `# U<'$  
Cnr=1E=  
9a2[_Wy  
} 0QP=$X  
})+iAxR  
//线程睡眠 0GlQWRa  
public static void sleep(int nSecond) 7W'&v+\  
{ &S=Qu?H  
try{ GrUpATIx  
Thread.sleep(nSecond); AGl#f\_^  
} ;hPVe _/  
catch(Exception e) (mr*Thy`@  
{ 0bpGPG's&  
e.printStackTrace (); bY-koJo  
} o~<jayqU  
} IL`LI J:O  
>V?W_oM)  
//日志 O{7rIy  
public static void log(String sMsg) Jk v!]C  
{ mGDy3R90  
System.err.println(sMsg); 3@nIoN'z  
} 2Wg:eh  
!</U"P:L  
Y<IuwS  
public static void log(int sMsg) * V7bALY  
{ ?V}ub>J/=  
System.err.println(sMsg); rK3KxG  
} 9M^5<8:  
} oxBTm|j7  
CIui9XNU  
CA1Jjm=  
/* _Ss}dU9  
**TestMethod.java kh@O_Q`j  
*/ H | C3{9  
package NetFox; a x)J!I18  
9B![l=Gh  
7Vk9{x$z  
public class TestMethod { h oO847  
2}7_Y6RS*  
P l!E$   
public TestMethod() amq,^  
{ ///xx/weblogic60b2_win.exe .Tm.M7  
try{ ,cxe"U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E=8GSl/Jx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KWeE!f 7G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DE7y\oO]  
fileFetch.start(); H0 Z o.Np  
} >Tjl?CS  
catch(Exception e){e.printStackTrace ();} HY eCq9S  
}t"K(oamm  
O8A(OfX  
} am !ssF5s  
-+u}u=z%  
.N>*+U>>P  
public static void main(String[] args) ?(U;T!n  
{ 4%zy$,|e  
new TestMethod(); q6*i/"mN*  
} 3.Yg3&"Z  
} J+Fev.9>  
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