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http断点续传简单实现(java)

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/* |,p"<a!+{w  
**SiteFileFetch.java u{_,S3Aa  
*/ m=sEB8P  
package NetFox; VS/M@y_./  
import java.io.*; W]#w4Fp!  
import java.net.*; >STthPO  
7bk77`qWr  
uDie205  
public class SiteFileFetch extends Thread { /M%>M]  
,IyQmN y  
( ne[a2%>  
SiteInfoBean siteInfoBean = null; //文件信息Bean iq*im$9 J  
long[] nStartPos; //开始位置 F$)l8}  
long[] nEndPos; //结束位置 2PYnzAsl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &RYdSXM  
long nFileLength; //文件长度 V\Gs&>  
boolean bFirst = true; //是否第一次取文件 E+i*u   
boolean bStop = false; //停止标志 z'm}p  
File tmpFile; //文件下载的临时信息 UP^8Yhdo  
DataOutputStream output; //输出到文件的输出流 Ny2 Z <TW  
_i {Y0d+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) b'\Q/;oz>  
public SiteFileFetch(SiteInfoBean bean) throws IOException ":$4/b6  
{ s-#EV  
siteInfoBean = bean; c 9f"5~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r@3-vLI!u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }lIc{R@H  
if(tmpFile.exists ()) V*b/N  
{ Cu8mNB{H  
bFirst = false; 3~T ~Bs  
read_nPos(); ekvs3a^  
} (O{OQk;CF  
else fr/EkL1Dl  
{ ?4%H(k5A  
nStartPos = new long[bean.getNSplitter()]; [(@K;6o  
nEndPos = new long[bean.getNSplitter()]; -y-}g[`  
} H[u9C:}9b  
gZ4' w`4r  
sNDo@u7  
fgd2jr 3T  
} x|a&wC2,{  
iT :3e%  
4%J0e'iN  
public void run() ot<d FvD  
{ uP'L6p5  
//获得文件长度 uC;_?Bve  
//分割文件 P)`^rJ6  
//实例FileSplitterFetch FuiR\"Ww  
//启动FileSplitterFetch线程 xT"V9t[f  
//等待子线程返回 QCW4gIp  
try{ D_d>A+  
if(bFirst) xRD+!3  
{ (U.Go/A#wE  
nFileLength = getFileSize(); ;|WUbc6&g  
if(nFileLength == -1) OM[MRZEh G  
{ FE\E%_K'n7  
System.err.println("File Length is not known!"); kw$ 7G1Q  
} 4CF;>b f~  
else if(nFileLength == -2) Ncz4LKzt  
{ =@Oo3*>  
System.err.println("File is not access!"); \:4*h  
} 9VxM1-8Gs  
else p-}X=O$  
{ oh8:1E,I  
for(int i=0;i<nStartPos.length;i++) 9,'m,2%W  
{ Qb^G1#r@C  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J _O5^=BP  
} W^[FWFUTY  
for(int i=0;i<nEndPos.length-1;i++) Y/5M)AyJt  
{ ~o!- [  
nEndPos = nStartPos[i+1]; Vx$;wU Y  
} %Xd*2q4*  
nEndPos[nEndPos.length-1] = nFileLength; =:&xdphZ+  
} .J75bX5  
} G x[ZHpy;  
aj`&ca8  
P~trxp=k  
//启动子线程 rw'+2\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '(5GR I<  
for(int i=0;i<nStartPos.length;i++) v8ap"9b  
{ lD,2])>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -'$ob~*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :/T\E\Qr  
nStartPos,nEndPos,i); 8 ??-H0P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |Mq+QDTTw~  
fileSplitterFetch.start(); G\gjCp?!  
} TN0KS]^A3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rM7qBt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I_<VGU k  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6j(/uF4!#  
nEndPos = " + nFileLength); vUpAW[[  
// fileSplitterFetch[nPos.length-1].start(); &'z_:Wm  
M1kA-Xr  
,R[$S"]!SH  
//等待子线程结束 UGPDwgq\v  
//int count = 0; Vu5?;|^:  
//是否结束while循环 BD C DQ  
boolean breakWhile = false; E@SFK=`  
=K`.$R  
>1s a*Wf  
while(!bStop) jo:Z  
{ W"Ip]LJ  
write_nPos(); <K[y~9u  
Utility.sleep(500); 63W;N7@  
breakWhile = true; j*DPW)RkKX  
StI N+S@Z  
sC-o'13  
for(int i=0;i<nStartPos.length;i++) ^ #:;6^Su  
{ 072C!F  
if(!fileSplitterFetch.bDownOver) IA`voO$  
{ Cb;6yE)!Z  
breakWhile = false; AY/.vyS  
break; vXDs/,`r  
} jaoZ}}V_$  
} [Fr](&Tx  
if(breakWhile) aRMlE*yW  
break; ~n]5iGz  
_@ao$)q{J  
E'LI0fr  
//count++; 9z#8K zXg  
//if(count>4) DU!T#H7  
// siteStop(); '3l TI  
} fUjo',<s  
 ~71U s  
; JkSZs3  
System.err.println("文件下载结束!"); Ce}`z L  
} 8 Rj5~+5  
catch(Exception e){e.printStackTrace ();} ^@^8iZ  
} ;\RV C 7  
c[Fc3  
_KH91$iW8m  
//获得文件长度 ,R{&x7  
public long getFileSize() I0}.!  
{ ukR0E4p  
int nFileLength = -1; U<j5s\Y,  
try{ lCU clD  
URL url = new URL(siteInfoBean.getSSiteURL()); & &}_[{fc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P)Adb~r  
httpConnection.setRequestProperty("User-Agent","NetFox"); h[remR# 3\  
N )Z>]&5  
W;OGdAa_  
int responseCode=httpConnection.getResponseCode(); Clum m@z;#  
if(responseCode>=400) P =X]'m_B  
{ =2p?_.|'  
processErrorCode(responseCode); (kxS0 ]=  
return -2; //-2 represent access is error oYu xkG  
} O=o}uB-*6  
IBT>&(cnV  
T)zk2\u  
String sHeader; eft=k}  
pQa51nc  
O\=Z;}<N  
for(int i=1;;i++) F1yn@a "=J  
{ OR@ 67Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9kD#'BxC  
//Utility.log(in.readLine()); 8T3,56 >  
sHeader=httpConnection.getHeaderFieldKey(i); ^)dsi  
if(sHeader!=null) CPJ<A,V  
{ ~wa4kS<>  
if(sHeader.equals("Content-Length")) 5eTA]  
{ 7:UeE~ uB:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d7V/#34  
break; }3*<sxw7<  
} -N' (2'  
} jW:7PS  
else ~}_^$l8#-Q  
break; "^4*,41U  
} *Dp&;,b  
} %p}vX9U')  
catch(IOException e){e.printStackTrace ();} -gs I:-Xo  
catch(Exception e){e.printStackTrace ();} o-8{C0>:  
{ I{ 0rV  
wiN0|h>,  
Utility.log(nFileLength); |ty&}'6C  
Z[@ i/. I  
t utk*|S  
return nFileLength; \tgY2 :  
} e4YfJd  
;?Pz0,{h  
hCQOwk#  
//保存下载信息(文件指针位置) H(^Eh v>  
private void write_nPos() H9T~7e+  
{ #ZZe*B!s_  
try{ =IL\T8y09  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1GN^ui a7  
output.writeInt(nStartPos.length); FF8jW1  
for(int i=0;i<nStartPos.length;i++) !RKuEg4hQ  
{ 3/RwCtc  
// output.writeLong(nPos); gT8(LDJ  
output.writeLong(fileSplitterFetch.nStartPos); )q<VZ|V  
output.writeLong(fileSplitterFetch.nEndPos); WM+8<|)n  
} {7e(0QK  
output.close(); FS"Ja`>j~  
} I=L[ "]  
catch(IOException e){e.printStackTrace ();} )?72 +X  
catch(Exception e){e.printStackTrace ();} eCI'<^  
} vsI;ooR>  
R2)@Q  
qJ;~ANwt  
//读取保存的下载信息(文件指针位置) XIIq0I  
private void read_nPos() %wbdg&^  
{ u(Mbp$R' ?  
try{ ?i<l7   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }%XB*pzQ  
int nCount = input.readInt(); 0N1t.3U  
nStartPos = new long[nCount]; L\4rvZa  
nEndPos = new long[nCount]; 8O^x~[sQ  
for(int i=0;i<nStartPos.length;i++) [+WsVwyf?  
{ mu B Y  
nStartPos = input.readLong(); ?w/p 9j#  
nEndPos = input.readLong(); | lLe^FM  
} a#1r'z~]}  
input.close(); M{L<aYe  
} 0L>3 i8'  
catch(IOException e){e.printStackTrace ();} 7#)k-S!B  
catch(Exception e){e.printStackTrace ();} H r:*p6  
} `ulQ C  
g+o$&'\  
rai'x/Ut}+  
private void processErrorCode(int nErrorCode) :3M ,]W]  
{ | co#X8J  
System.err.println("Error Code : " + nErrorCode); HK[%'OQ  
} _&= `vv'  
o*$KiD  
V_ 6K?~j  
//停止文件下载 1XN%&VR>^D  
public void siteStop() Gm- "?4(  
{ w^L`"  
bStop = true; ,i*rHMe  
for(int i=0;i<nStartPos.length;i++) `)O9 '568  
fileSplitterFetch.splitterStop(); N~|f^#L  
q;AD#A|\  
[ &Wy $  
} Y's=31G@  
} TY]0aw2]|7  
//负责部分文件的抓取 <x`yoVPiZg  
**FileSplitterFetch.java E:rJi]  
*/ S[y'{;  
package NetFox; m !:F/?B  
(lwV(M  
` ,T .  
import java.io.*; I e!KIU  
import java.net.*; O[Z$~  
}'<Z&NW6  
7NEOaX(J9  
public class FileSplitterFetch extends Thread { Gh_5$@ hF  
!o| ex+z;  
86%k2~L  
String sURL; //File URL -~.+3rcZ]  
long nStartPos; //File Snippet Start Position tic3a1  
long nEndPos; //File Snippet End Position j&DlI_  
int nThreadID; //Thread's ID UVXruH  
boolean bDownOver = false; //Downing is over e[k\VYj[  
boolean bStop = false; //Stop identical Fz8& Jn!  
FileAccessI fileAccessI = null; //File Access interface e|A=sCN-  
%w_MRC  
!T`g\za/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~a=]w#-KD  
{ AYNz {9  
this.sURL = sURL; <!dZ=9^^ 1  
this.nStartPos = nStart; Tx ?s?DwC  
this.nEndPos = nEnd; pe[huYE  
nThreadID = id; {{A=^rr%C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `mkOjsj &  
} :V8oWMY  
wB8548C}-  
L^^f.w#m  
public void run() "j%Gr :a  
{ 1 =?pL$+G  
while(nStartPos < nEndPos && !bStop) d >M0:  
{ XPYf1H  
lN.&46 e  
W*H%\Y:N  
try{ 6jr}l  
URL url = new URL(sURL); O0^Y1l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z@[n?t!7k  
httpConnection.setRequestProperty("User-Agent","NetFox"); *mWS+xcU(L  
String sProperty = "bytes="+nStartPos+"-"; !OV+2suu1  
httpConnection.setRequestProperty("RANGE",sProperty); [HXd|,~_j-  
Utility.log(sProperty); El`G<esX  
S@\&^1;4Hv  
#\~m}O,  
InputStream input = httpConnection.getInputStream(); {w>ofyqfp&  
//logResponseHead(httpConnection); ]I~BgE;C9  
5'Mw{`  
U&kdR+dB  
byte[] b = new byte[1024]; ADP[KZO$ 4  
int nRead; ke*&*mx"L  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )$Fw<;4  
{ @ 6jKjI  
nStartPos += fileAccessI.write(b,0,nRead); ;).QhHeg>  
//if(nThreadID == 1) `5t~ Vlp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 99h#M3@!  
} /\jRr7 Cd  
%|}7YH41  
l5e`m^GK  
Utility.log("Thread " + nThreadID + " is over!"); K(mzt[n(  
bDownOver = true; C/"Wh=h6  
//nPos = fileAccessI.write (b,0,nRead); 4>=Y@z  
} O6-"q+H)  
catch(Exception e){e.printStackTrace ();} aLevml2:T  
} j~2t^Qz  
} -J!k|GK#MX  
.R+n}>+K  
^sZHy4-yK#  
//打印回应的头信息 /4BYH?*  
public void logResponseHead(HttpURLConnection con) aj+I+r"~  
{ >48)@sS  
for(int i=1;;i++) &)Wm rF  
{ e]jzFm~  
String header=con.getHeaderFieldKey(i); BGB.SN#q+  
if(header!=null) 9&c *%mm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); MM+nE_9lV  
Utility.log(header+" : "+con.getHeaderField(header)); ~xZ )btf  
else nRZ T~S4  
break; b|Ed@C  
} p t{/|P  
} 5geZ6]|  
q|;+Wp?  
5[qx5|O  
public void splitterStop() fwyz|>H_Y(  
{ j"+R*H(#  
bStop = true; n]JfdI  
} +>h'^/rAE  
8-vNXvl  
0.Nik^~  
} BYDOTy/%nJ  
oX]c$<w5  
 b|h`v  
/* u|8V7*)3  
**FileAccess.java My >{;n=}  
*//文件访问(定位,写) _Ai\XS Am  
package NetFox; DCtrTX  
import java.io.*; 8J7<7Sx  
QXT *O  
EEp,Z`  
public class FileAccessI implements Serializable{ `Axn  
ab5z&7Re6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {wf e!f  
RandomAccessFile oSavedFile; [.iz<Yh  
long nPos; oxm3R8 S  
hz+x)M`Y  
OGO4~Up  
public FileAccessI() throws IOException $5l=&  
{ T%:W6fH7  
this("",0); <N;HB&mr  
} j.rJfbE|X  
#$>m`r  
F0FF:><  
public FileAccessI(String sName,long nPos) throws IOException RnkrI~x  
{ xBcE>^{1.  
oSavedFile = new RandomAccessFile(sName,"rw"); X6@G)68  
this.nPos = nPos; ZA4vQDW  
oSavedFile.seek(nPos); n.xW"omN  
} ?g'? Ou  
*e05{C:kS  
"(d7:!%  
public synchronized int write(byte[] b,int nStart,int nLen) -z4pI=  
{ vvG#O[| O  
int n = -1; *] cm{N  
try{ y| %rW  
oSavedFile.write(b,nStart,nLen); h|1 /Q (  
n = nLen; JuT~~Z  
} :AB$d~${M>  
catch(IOException e) 13P8Zmco  
{ .qBf`T;  
e.printStackTrace (); "h}miVArS  
} }%9A+w}o  
Lm}:`  
Fn!kest  
return n; ebS>_jD  
} !N1DJd  
p9)'nU'\t  
+K%4jIm  
} LY^pmak  
Hh8)d/D  
~O}LAzGb  
/* v [ 4J0  
**SiteInfoBean.java @nS+!t{  
*/  + >oA@z  
package NetFox; 7,2bR  
^J]~&.l  
1yN/+Rq  
public class SiteInfoBean { hIPU%  
.5zqpm  
Og`w~!\  
private String sSiteURL; //Site's URL =)3tVH&  
private String sFilePath; //Saved File's Path 3X&}{M:Qo  
private String sFileName; //Saved File's Name 3R[5prE<  
private int nSplitter; //Count of Splited Downloading File *.J)7~(P  
#yk m  
]QS? fs Z  
public SiteInfoBean() tQ:)j^\  
{//nSplitter的缺省值为5 Ln})\ UDK)  
//default value of nSplitter is 5 xCMcS~ 3/  
this("","","",5); @4D$Xl  
} t .&YD x  
RS~jHwIh  
^U.8grA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4cni_m]  
{ 8`*Wl;9u  
sSiteURL= sURL; G.,dP +i  
sFilePath = sPath; :.IVf Zw  
sFileName = sName; VMUK|pC4 K  
this.nSplitter = nSpiltter; %_!YonRY|X  
SAt{At  
fKMbOqU_  
} VSCOuNSc  
nTweQ  
#s)Wzv%OX  
public String getSSiteURL() FaC;vuSpy  
{ M3350  
return sSiteURL; S3u>a\  
} 8=H!&+aGh  
7Xi)[M?)#  
'dp3>4  
public void setSSiteURL(String value) "]81+ D  
{ p*8LS7UT  
sSiteURL = value; X/fk&Cp  
}  h+Dp<b  
C{<qc,!4  
@54D<Lj  
public String getSFilePath() ON|Bpt2Qp  
{ WhsTKy&E  
return sFilePath; {1.t ZCMT  
} F7wpGtt  
wIIxs_2Q0c  
4~8++b1/;  
public void setSFilePath(String value) hmv"|1Sa!~  
{ -ckk2D?  
sFilePath = value; -(4)lw>U  
} Bkvh]k;F8  
b/:&iG;  
6C>"H  
public String getSFileName() s_A<bW566F  
{ KPI c?|o/6  
return sFileName; {#aW")x^#  
} ?r"'JO.w  
7{ zkqug  
w~A{]s{ 4  
public void setSFileName(String value) :gMcl"t--  
{ :<l(l\MC  
sFileName = value; a%a_sR\)  
} (a0q*iC%  
I^*&u,  
|X/ QSL  
public int getNSplitter() j] \3>.  
{ N6Mo|  
return nSplitter; }=CL/JHz  
} 1@*qz\ YY  
dGU io?  
zWYm* c"n\  
public void setNSplitter(int nCount) Ww&~ZZZ {  
{ Fdsaf[3[v  
nSplitter = nCount; >h+[#3vD  
} e|)6zh<O:  
} 42X N*br  
:r%H sur(  
Gq_rZo(@  
/* |F _ Z  
**Utility.java a g Za+a  
*/ {kGcZf3h  
package NetFox; \mRRx#-r%  
^V]DQ%v"I  
<BoDLvW>  
public class Utility { =\;yxl  
+X)n}jh  
tHlKo0S$0  
public Utility() !QK ~l  
{ 5ve4u  
DA'A-C2  
Hgs=qH  
} ,MkldCV  
{k.Dy92  
//线程睡眠 jx_n$D  
public static void sleep(int nSecond) :2#8\7IU^'  
{ x2gnB@t  
try{ So &c\Ff  
Thread.sleep(nSecond); ;4DqtR"7Y  
} *LnY}#  
catch(Exception e) d5?"GFy  
{ TNY d_:j  
e.printStackTrace (); Y@WCp  
} fJ"#c<n  
} b"x[+&%i  
+^!;J/24  
//日志 1eG@?~G  
public static void log(String sMsg) @R+bR<}]  
{ vwZd@%BO  
System.err.println(sMsg); 56!>}!8!  
} Sb_T _m  
4}nsW}jCc  
v/%q*6@  
public static void log(int sMsg) Qg]8~^ Q<  
{ x!rHkuH~  
System.err.println(sMsg); 2?; =TJo$  
} cZ$!_30N+  
} I{Pny/d`  
).+!/x  
<.c@l,[.z  
/* \VW&z:/*pZ  
**TestMethod.java 8 jom)a  
*/ J:M)gh~#  
package NetFox; :v/6k  
>pa tv  
mi~ BdBv  
public class TestMethod { d\nBc6  
Ve<3XRq|8  
Pw4j?pv2  
public TestMethod() !ra CpL9;  
{ ///xx/weblogic60b2_win.exe #A|~s;s>N  
try{ 1c=Roiq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,}&E=5MF\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (n{sp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $"Oy }  
fileFetch.start(); B7Um G)C  
} A:"J&TbBx  
catch(Exception e){e.printStackTrace ();} }`/wj  
U:]b&I  
Ov{fO  
} -C$Z%I7 0  
_`!@  
*"E?n>b  
public static void main(String[] args) qlUYu"`i  
{ uNLB3Rdy}  
new TestMethod(); ]y 6`9p  
} ;S+c<MSl  
} }z&P^p)R  
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