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http断点续传简单实现(java)

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/* YOCEEh?  
**SiteFileFetch.java "M I';6  
*/ O%b byR2  
package NetFox; F3tps jQ  
import java.io.*; gQ1 obT"|  
import java.net.*; SN{z)q  
e8m,q~%#/  
H;H=8'  
public class SiteFileFetch extends Thread { @u~S!(7.Wi  
baxZ>KNi  
nm'l}/Ug  
SiteInfoBean siteInfoBean = null; //文件信息Bean dC11kq qj  
long[] nStartPos; //开始位置 _z\/{  
long[] nEndPos; //结束位置 /d`"WK,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^^y eC|~N:  
long nFileLength; //文件长度 Sg#XcTG  
boolean bFirst = true; //是否第一次取文件 G7Nw}cVJ)  
boolean bStop = false; //停止标志 zWsr|= [  
File tmpFile; //文件下载的临时信息 i\R0+ O{  
DataOutputStream output; //输出到文件的输出流 ui8 Q2{z  
Y\|#Lu>B  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &quY^j  
public SiteFileFetch(SiteInfoBean bean) throws IOException Zk3Pv0c  
{ eA!o#O.  
siteInfoBean = bean; D6 B-#u!M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @^{Hq6_`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mx c)Wm<4  
if(tmpFile.exists ()) Q7%4`_$!  
{ kfy!T rf  
bFirst = false; 6Q.S  
read_nPos(); .l}Ap7@  
} ~9X^3.nI  
else @AyteHK  
{ <izQ]\kL  
nStartPos = new long[bean.getNSplitter()]; /{M<FVXK+|  
nEndPos = new long[bean.getNSplitter()]; tvkdNMyX%9  
} &|v)   
h`[$ Bp  
,75)  
L/3A g* ]  
} B#sCB&(  
)6|L]'dsZ  
NOb`)qb  
public void run() "oP^2|${  
{ T j$'B[cv  
//获得文件长度 e UPa5{P  
//分割文件 9&mSF0q  
//实例FileSplitterFetch o%d TcoCN  
//启动FileSplitterFetch线程 @s5=6z]=H  
//等待子线程返回 1? >P3C  
try{ nt.LiM/L  
if(bFirst) QX,$JM3  
{ exRw, Nk4  
nFileLength = getFileSize(); 7DB_Z /uU  
if(nFileLength == -1) ,_z79tC{s  
{ FX:`7c]:9  
System.err.println("File Length is not known!"); #]#9Xq  
} x*7@b8J  
else if(nFileLength == -2) Q>niJ'7WF  
{ j,IRUx13f  
System.err.println("File is not access!"); !MbzFs~  
} Hv,|XE@Y  
else LoF/45|-<  
{ ^r}c&@  
for(int i=0;i<nStartPos.length;i++) ~.a"jYb7A}  
{ ggso9ZlLu+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sp `l>BL  
} FO{=^I5YA  
for(int i=0;i<nEndPos.length-1;i++) ycA<l"  
{ PKm|?kn{0(  
nEndPos = nStartPos[i+1]; h my%X`%j  
} r )|3MUj  
nEndPos[nEndPos.length-1] = nFileLength; l#)X/(?;  
} cNll??j  
} `oRyw6Sko  
h~dQ5%  
#w$Y1bjn  
//启动子线程 {Jr1K,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *k?:k78L  
for(int i=0;i<nStartPos.length;i++) E)b$;'  
{ R2bqhSlF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _&KqmQ8$7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Im]@#X  
nStartPos,nEndPos,i); ]8G 'R-8}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WtSs:D  
fileSplitterFetch.start(); K#"=*p,  
} r>mBe;[TX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u6iW1,#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Dy08.Sss  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b,!C8rJ  
nEndPos = " + nFileLength); 1{uxpYAP=  
// fileSplitterFetch[nPos.length-1].start(); kG^76dAQL  
n ]%2Kx  
B|`?hw@g+  
//等待子线程结束 5epI'D  
//int count = 0; a@}.96lStD  
//是否结束while循环 %VHy?!/  
boolean breakWhile = false; (leX` SN0u  
Iix,}kzss  
r&=ulg  
while(!bStop) Bfb~<rs[  
{ ct+F\:e  
write_nPos(); R'c*CLaiE  
Utility.sleep(500); q~{) {t;  
breakWhile = true; %G?@Hye3  
*)^6'4=  
Y,L`WeQY.  
for(int i=0;i<nStartPos.length;i++) )"x6V""Rb  
{ c~|(j \FI  
if(!fileSplitterFetch.bDownOver) 8t+eu O  
{ ;`AB-  
breakWhile = false; +IZ=E >a  
break; X4!93  
} UB~K/r`.|  
} zCs34=3 D[  
if(breakWhile) HcRw9,I'  
break; bW yimr&B  
FvT&nb{  
(Tx_`rO4VY  
//count++; 0aT:Gy;  
//if(count>4) q` S ~w  
// siteStop(); Y:*% [\R  
} vG|!d+  
@ f[-  
+.cpZqWn3  
System.err.println("文件下载结束!"); i?L=8+9f  
} QE 4   
catch(Exception e){e.printStackTrace ();} /*C!]Z>.  
} UiU/p  
C T~6T&'  
T!/o^0w  
//获得文件长度 "LlpZtw  
public long getFileSize() NKY|Z\  
{ n6Oz[7M  
int nFileLength = -1; B>{%$@4  
try{ (l5p_x  
URL url = new URL(siteInfoBean.getSSiteURL()); ^^q&VL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  %:26v  
httpConnection.setRequestProperty("User-Agent","NetFox"); d+n2 c`i  
{lK2yi  
HDm]njF%qQ  
int responseCode=httpConnection.getResponseCode(); 2gWR2 H@  
if(responseCode>=400) lHiWzt u  
{ ~[H8R|j "  
processErrorCode(responseCode); .Ys e/oEo  
return -2; //-2 represent access is error &%J{uRp  
} e;i 6C%DB  
v^A+LZ*d  
QQ?t^ptv  
String sHeader; tPyk^NJ;  
pPL=(9d  
/gAT@Vx  
for(int i=1;;i++) SIK:0>yK"  
{ 0E\#!L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pq*e0uW  
//Utility.log(in.readLine()); LhG\)>Y%  
sHeader=httpConnection.getHeaderFieldKey(i); {S0-y  
if(sHeader!=null) z ]f(lwo{  
{ #-|fdcb  
if(sHeader.equals("Content-Length")) 1dvP2E  
{ ` wa;@p+j8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *eg0^ByeD  
break; "DN,1Q lCp  
} 8Z !%rS  
} ,ye}p 1M  
else %g :Q?   
break; c5p,~z_Dtu  
} (]w6q&,  
} tE %g)hL-  
catch(IOException e){e.printStackTrace ();} <F^9ML+'  
catch(Exception e){e.printStackTrace ();} 2n.HmS  
NX\AQVy9  
,nf}4  
Utility.log(nFileLength); ;R= n<=Axa  
re*Zs}(N\  
sOqFEvzo1%  
return nFileLength; ^i@anbH  
} -9vNV:c  
B/X$ZQ0  
RUY7Y?  
//保存下载信息(文件指针位置) kq| !{_  
private void write_nPos() G#[A'tbKk  
{ yjT>bu]  
try{ DN:| s+Lz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AL":j6!OQ  
output.writeInt(nStartPos.length); 20I`F>-*  
for(int i=0;i<nStartPos.length;i++) &G2&OFAr]q  
{ 4eWv).  
// output.writeLong(nPos); gWgp:;Me  
output.writeLong(fileSplitterFetch.nStartPos); Kyx9_2  
output.writeLong(fileSplitterFetch.nEndPos); F'MX9P  
} 4prJ!k  
output.close(); iw#~xel<ez  
} !h1:AW_iz  
catch(IOException e){e.printStackTrace ();} Bq$IBAot  
catch(Exception e){e.printStackTrace ();} #^$_/Q#C  
} Oj-\  
?Uq"zq  
;6@sC[  
//读取保存的下载信息(文件指针位置) HGAi2+&  
private void read_nPos() LqYyIbsvf  
{ Tdh(J",d  
try{ S ,F[74K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?OW!D?  
int nCount = input.readInt(); g}!{_z  
nStartPos = new long[nCount]; Uha.8  
nEndPos = new long[nCount]; +TbAtkEF*  
for(int i=0;i<nStartPos.length;i++) XQ~Xls%]   
{ z~2{`pET  
nStartPos = input.readLong(); W=HvMD  
nEndPos = input.readLong(); lU 62$2  
} u xyj6(  
input.close(); NzAh3k  
} $'KQP8M+  
catch(IOException e){e.printStackTrace ();} OxDq LX  
catch(Exception e){e.printStackTrace ();} e6MBy\*n  
} nA0%M1a  
.@fA_8  
X$KTsG*  
private void processErrorCode(int nErrorCode) ZBDF>u@  
{ JPF6zzl)  
System.err.println("Error Code : " + nErrorCode); a X1b(h2  
} u<8b5An;  
Mf14> `<`  
wU|@fm"  
//停止文件下载 +D5gbxZX  
public void siteStop() A|LO!P,w  
{ 3E wdu  
bStop = true; w71YA#cg  
for(int i=0;i<nStartPos.length;i++) %|e)s_%XE  
fileSplitterFetch.splitterStop(); -E1-(TS  
d<d3j9u(#  
CNb(\]  
} "dP-e  
} ,c:NdY(,)  
//负责部分文件的抓取 tC|?Kl7  
**FileSplitterFetch.java ]y.V#,6e  
*/ (o*YGYC  
package NetFox; \dCGu~bT  
#f"eZAQ {  
z'l HL  
import java.io.*; ~;9n6U  
import java.net.*; {@CQ (  
M 6&=-  
0U~$u  
public class FileSplitterFetch extends Thread { Tr_gc~  
$F^VtCx2&  
Ho&:Zs  
String sURL; //File URL f2[R2sto@  
long nStartPos; //File Snippet Start Position {ol7*%u  
long nEndPos; //File Snippet End Position Uj;JN}k  
int nThreadID; //Thread's ID 7LU^Xm8  
boolean bDownOver = false; //Downing is over $M)SsD~  
boolean bStop = false; //Stop identical !#pc@(rE  
FileAccessI fileAccessI = null; //File Access interface ;@=3 @v  
pMT7/y-  
QL8C!&=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7Tk//By7  
{ sJx_X8  
this.sURL = sURL; 9HO9>^  
this.nStartPos = nStart; {[#)Q.2  
this.nEndPos = nEnd; |` ~ioF  
nThreadID = id; O`0r'&n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /i8OyRpSyk  
} r'Wf4p^Xd  
Hk;;+'-  
W6T4Zsg  
public void run() [3bPoAr\  
{ 7zCJ3p  
while(nStartPos < nEndPos && !bStop) 2`*w*  
{ ~\(c;J*Ir  
iXy1{=BDv  
FbroI>"e  
try{ ]fzXrN_  
URL url = new URL(sURL); UstUPO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }| MX=:@*  
httpConnection.setRequestProperty("User-Agent","NetFox"); f|VCibI  
String sProperty = "bytes="+nStartPos+"-"; N#Rb8&G)b  
httpConnection.setRequestProperty("RANGE",sProperty); EA(4xj&:U  
Utility.log(sProperty); 1Sz tN3'q  
}?,YE5~  
Bk\Y v0  
InputStream input = httpConnection.getInputStream(); Wz.iDRFl  
//logResponseHead(httpConnection); o3hgkoF   
;Tr,BfV|Bf  
F}{%*EJ  
byte[] b = new byte[1024]; QP.Lq }  
int nRead; ymxA<bICS8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BW)-F (v   
{ hhaiH i!$  
nStartPos += fileAccessI.write(b,0,nRead); ]?+i6 [6U  
//if(nThreadID == 1) X PyDZk/m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qu[QcB{ro-  
} Fn .J tIu  
;+XrCy!.)L  
ss%,  
Utility.log("Thread " + nThreadID + " is over!"); pWKE`x^  
bDownOver = true; WfaMu| L  
//nPos = fileAccessI.write (b,0,nRead); }(8>&  
} g>h/|b w4  
catch(Exception e){e.printStackTrace ();} 2|^@=.4\  
}  7qy PI  
} z*h:Nt%.  
2j8GJU/L  
te( H6c#0  
//打印回应的头信息 uCr& `  
public void logResponseHead(HttpURLConnection con) BJwuN  
{ _M/N_Fm  
for(int i=1;;i++) #?w07/~L  
{ LH2B*8=^2  
String header=con.getHeaderFieldKey(i); I+H~ 5zq.  
if(header!=null) sR1_L/.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5?;<^J  
Utility.log(header+" : "+con.getHeaderField(header)); 7tlK'j'  
else z(LR!hr  
break; KxK,en4)+  
} cZ_)'0  
} exJc[G&t(  
^%,{R},s  
YA$YT8iMe  
public void splitterStop() ,5v'hG  
{ =xm7i#1  
bStop = true; IWu=z!mO  
} A]!0Z:{h%  
9oJM?&i  
<b H *f w  
} nC p/.]Y*  
'Wnh1|z  
w@^J.7h^  
/* *@''OyL  
**FileAccess.java Mc.{I"c@  
*//文件访问(定位,写) |gI>Sp%Fu  
package NetFox; @$r[$D v  
import java.io.*; sMGo1pG(  
N_NN0  
I}bu  
public class FileAccessI implements Serializable{ %3qjgyLZ|  
_ +DL   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FzX ;~CA  
RandomAccessFile oSavedFile; >[aR8J/U  
long nPos; ?pZU'5le`  
5zBA]1PY  
GP c B(  
public FileAccessI() throws IOException  Kg';[G\  
{ (|<S%?}J  
this("",0); fX`u"`o5  
} AuQ|CXG-\  
4Y?2u  
R 9` [C  
public FileAccessI(String sName,long nPos) throws IOException zN!W_2W*  
{ + )Qu,%2   
oSavedFile = new RandomAccessFile(sName,"rw"); e-y$&[  
this.nPos = nPos; ?YR;o4  
oSavedFile.seek(nPos); 9JP:wE~y  
} sPi  
K+vD&Z^  
(G> su  
public synchronized int write(byte[] b,int nStart,int nLen) HNS^:X R  
{ P}8hK   
int n = -1; *fc8M(]&d  
try{ yZ6WbI8n  
oSavedFile.write(b,nStart,nLen); AVQcD`V3B  
n = nLen; UCcr>  
} ,;}   
catch(IOException e) w{DU<e:  
{ "'[M~Js  
e.printStackTrace (); s`=| D'G(=  
} 8<; .  
zK~8@{l}_"  
3R< r[3WP  
return n; w3,KqF  
} )1Bz0:  
C`[2B0  
C{/U;Ie-b  
} n~6$CQ5dF(  
u!D?^:u=)  
a?+C]u?_D  
/* ;>Z+b#C[  
**SiteInfoBean.java y_Lnk=Q ^  
*/ n )X%&_  
package NetFox; P 2_!(FZ<l  
NW6;7nWb  
gS<p~LPf  
public class SiteInfoBean { tRU/[?!  
>97YK =  
[]@@  
private String sSiteURL; //Site's URL y`zdI_!7  
private String sFilePath; //Saved File's Path u W,J5!  
private String sFileName; //Saved File's Name sZ=!*tb-  
private int nSplitter; //Count of Splited Downloading File 0x~+=GUN  
o(e(| k {  
]~]TZb  
public SiteInfoBean() mH$`)i8  
{//nSplitter的缺省值为5 h81giY]  
//default value of nSplitter is 5 VgXT4gO!  
this("","","",5); (nLzWvN  
} xMk>r1Ud  
c\ZI 5&4jT  
X[?fU&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1sg:8AA  
{ cZN<}n+q  
sSiteURL= sURL; h!dij^bD  
sFilePath = sPath; 17'd~-lE  
sFileName = sName; ~s&r.6 DW  
this.nSplitter = nSpiltter; S Yi!%  
X$;x2mz nM  
]Y]]X[@  
} !QVhP+l'H  
).jQ+XE'>  
!:\0}w$-  
public String getSSiteURL() Vyi.:lL _8  
{ w%`S>+kX&  
return sSiteURL; spP[S"gI  
} | t:UpP  
$&.(7F^D  
3_wR2AU~  
public void setSSiteURL(String value) EFDmNud`Q  
{ [@qjy*5p  
sSiteURL = value; $A~aNI  
} -`5]%.E&8  
xT&/xZLT  
[gUD +  
public String getSFilePath() VM5'd  
{ ugN%8N  
return sFilePath; 02EX_tt),  
} Yz2N(g[  
=A,T:!}'  
S}Wj.l+F  
public void setSFilePath(String value) tOVTHx3E]  
{ ^(  
sFilePath = value; $'CS/U`E}  
} rx| ,DI  
4j0;okQWV'  
8cZ[Kl%  
public String getSFileName() FP&Ykx~  
{ F\&wFA'J  
return sFileName; N>EMVUVS  
} ,k.")  
j{FRD8]V  
u `ww  
public void setSFileName(String value) l$!ExXEZO;  
{ V"8Go;[  
sFileName = value; U4dfO=  
} M3UC9t9]  
J0k!&d8  
Tr>_R%bK  
public int getNSplitter() O=}  
{ zytW3sTZA  
return nSplitter; GBZu<t/  
} m==DBh  
z+oy#p6+F.  
$27OrXQ|  
public void setNSplitter(int nCount) *lZ V3F  
{ rgXX,+cO  
nSplitter = nCount; q}jh>`d  
} V&j]*)  
} VXk[p  
lrkgsv6  
LsGO~EiJ  
/* 0ie)$fi  
**Utility.java Vq#0MY)2gS  
*/ a"4X7 D+  
package NetFox; 21<Sfsc$  
C+!=C{@7di  
Cs"ivET  
public class Utility { .(p_YjIA  
P;XA|`&  
kn$SG  
public Utility() d$\n@}8eZp  
{ 1M)88&  
)X*_oH=  
1)}hzA  
} qldm"Ul  
7^.g\Kt?  
//线程睡眠 SsMs#C8u%  
public static void sleep(int nSecond) ,,j >2Ts  
{ /w6'tut  
try{ Xeja\5zB  
Thread.sleep(nSecond); zGd[sjL  
} 3`3my=   
catch(Exception e) qMVuBv  
{ TRgj`FG  
e.printStackTrace (); lM#/F\  
} to_dNJbv  
} w"kBAi&  
X/%!p<}:'  
//日志 :zIB3nT^  
public static void log(String sMsg) JC$_Pg!  
{ |w~*p N0  
System.err.println(sMsg); (:H4  
} oKkDG|IE  
wE9z@\z]  
vfDX~_N  
public static void log(int sMsg) Iza#v0  
{ yHf^6|$8  
System.err.println(sMsg); {J)gS  
} 6R3/"&P(/#  
} Y*jkUQ  
C@XnV=J  
4%yeEc ;z  
/* R Ee~\n+P^  
**TestMethod.java BUI#y `J  
*/ ~t*_  
package NetFox; _Nz?fJ:$@  
y9i+EV  
X+\=dhn69  
public class TestMethod { `} 'o2oZnG  
%dd B$(  
Xa'b @*o&  
public TestMethod() &F0>V o  
{ ///xx/weblogic60b2_win.exe =`MQKh,  
try{ |gk"~D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L Do~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?*q-u9s9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rV%;d[LB  
fileFetch.start(); MnY}U",   
} './qBJ  
catch(Exception e){e.printStackTrace ();} <gvgr4@^yR  
~O /B  
? R[GSS1  
} }*P;kV  
ucLh|}jJ5  
R6GlQ G  
public static void main(String[] args) bV)h\:oC  
{ ey>tUmt6?  
new TestMethod(); L?(1 [jB4G  
} cE,,9M@^  
} |BbrB[+ v[  
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