http断点续传简单实现（java)

/* dfj\RIV8  
**SiteFileFetch.java gQWd&)'muf  
*/ 2(YPz|~W  
package NetFox; JcO08
n  
import java.io.*; |1= !;.#  
import java.net.*; mryN}  
kAzd8nJ'  
2s ,8R  
public class SiteFileFetch extends Thread { h rN%  
w=b(X q+:  
2h^WYpCm  
SiteInfoBean siteInfoBean = null; //文件信息Bean rJfqA@  
long[] nStartPos; //开始位置 /FY2vDfU6  
long[] nEndPos; //结束位置 7YIK9edP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 I0= NaZ7  
long nFileLength; //文件长度 D vkxI<Xa  
boolean bFirst = true; //是否第一次取文件 8%{q%+  
boolean bStop = false; //停止标志 < a rZbM  
File tmpFile; //文件下载的临时信息 !E\[SjY@J  
DataOutputStream output; //输出到文件的输出流 eARk QV  
TJ@Cjy%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x<(b|2qf  
public SiteFileFetch(SiteInfoBean bean) throws IOException S4NL "m  
{ /M0/-pV9  
siteInfoBean = bean; g9h(sLSF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yWIm&Q:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rx~[Zs+*  
if(tmpFile.exists ()) F
 8yF  
{ qztV,R T  
bFirst = false; wNCCH55Pt  
read_nPos(); >R^@Ww;|q  
} i^Ut015q%  
else 2h~-  
{ *6ZCDm&N  
nStartPos = new long[bean.getNSplitter()]; 43:t \  
nEndPos = new long[bean.getNSplitter()]; P<dy3;  
} jB$SUO`*  
pR os{Uq"  
QOFvsJ<s  
'w/qcD-  
} 7G2PMe;$m  
h#YD~!aJ  
P!g-X%ngo  
public void run() Qu*1g(el!o  
{ K\!#4>yd  
//获得文件长度 }6zbT-i  
//分割文件 Ibr%d2yS=  
//实例FileSplitterFetch 1hQN8!:<  
//启动FileSplitterFetch线程 \|=mD}N  
//等待子线程返回 NC23Z0y  
try{
+JdZPb  
if(bFirst) =C7 khE  
{ #XIc "L)c  
nFileLength = getFileSize(); O_,O,1  
if(nFileLength == -1) cA`4:gp  
{ 8^ep/b&|  
System.err.println("File Length is not known!"); |WqOk~)[Z3  
} =jAFgwP\  
else if(nFileLength == -2) w_-+o^  
{ I`B'1"{  
System.err.println("File is not access!"); L_O$>c  
} W.}].7}h  
else H?rg5TI0  
{ rs8\)\z  
for(int i=0;i<nStartPos.length;i++) Csst[3V  
{ HD`>-E#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l[h'6+o  
} \{|ImCH  
for(int i=0;i<nEndPos.length-1;i++) T|4snU2M  
{ Pe7e?79  
nEndPos = nStartPos[i+1]; dDcZ!rRaL@  
} db
GgD=}o  
nEndPos[nEndPos.length-1] = nFileLength; LK7Xw3  
} ~5aE2w0K
 
} C0C0GqN,  
I*)VZW  
:-+4:S
  
//启动子线程 6vs3O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; v|t{1[C  
for(int i=0;i<nStartPos.length;i++) rz
Ld"`  
{ zQ)+/e(8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'ig, ATY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 649 !=  
nStartPos,nEndPos,i); [Eq<":)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W Ox_y,  
fileSplitterFetch.start(); QTJu7^O9  
} /p`&;/V|
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Epjff@7A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F9o6V|v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~9M!)\~  
nEndPos = " + nFileLength); {[#(w75R{  
// fileSplitterFetch[nPos.length-1].start(); ]#eh&jw  
nYw\'c  
P'[<AZ  
//等待子线程结束 yY=<'{!  
//int count = 0; MWwJzVL8  
//是否结束while循环 DguB  
boolean breakWhile = false; ';YgG<u  
s;.=5wcvi?  
!C&%T]  
while(!bStop) BWK IbG  
{ $[CA&Y.  
write_nPos(); =Viy^ieN$  
Utility.sleep(500); `lCuU~~ag  
breakWhile = true; k=n "+  
KCqqJ}G  
>M4"|W U_  
for(int i=0;i<nStartPos.length;i++) %$X\"  
{ iD_TP  
if(!fileSplitterFetch.bDownOver) ?Myh7  
{ v|@1(  
breakWhile = false; *8A6Q9YT  
break; %v=!'?VT  
} 78
Y@OL_$  
} gY5l.&  
if(breakWhile) /6tcSg)  
break; x-Z^Q C  
VWa|Y@Dc]  
o
Xal  
//count++; __\P`S_  
//if(count>4) v*TeTA %  
// siteStop(); zy)i1d  
} VTw/_Hf2p  
'D6 bmz  
sBjXE>_#)  
System.err.println("文件下载结束！"); `BT^a =5  
} I'_v{k5ZI  
catch(Exception e){e.printStackTrace ();} zixEMi[8  
} Q"}s>]k3_  
Bymny>.M  
Q1V2pP+=@  
//获得文件长度 /tC9G@Hl  
public long getFileSize() /bcY6b=:  
{ [b1hC ~I;  
int nFileLength = -1; PrnrXl S  
try{ /H&aMk}J@y  
URL url = new URL(siteInfoBean.getSSiteURL()); #5{sglC"|F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #93}E Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Vk:YL++  
<94WZ?{p  
fM":f| G  
int responseCode=httpConnection.getResponseCode(); {nRUH*(d9  
if(responseCode>=400) ^, wnp@
 
{ %V_eJC""?  
processErrorCode(responseCode); wRbw
  
return -2; //-2 represent access is error Gpu_=9vzv  
} Czu1)y  
OmNn,PCl8  
qZsnd7o{l.  
String sHeader; EAyukM2  
#s^s_8#&e  
SCq3Ds^  
for(int i=1;;i++) NsmVddj  
{ lU$X4JBzS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1v]t!}W:6  
//Utility.log(in.readLine()); uBRw>"c_*8  
sHeader=httpConnection.getHeaderFieldKey(i); Q\WXi  
if(sHeader!=null) ~d+O/:=K_  
{ %!wq:~B1  
if(sHeader.equals("Content-Length")) $rB!Ex{@ac  
{ PP4d?+;V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?*o;o?5s^  
break; Fwv\pJ}$  
} y
A}nPXrd  
} g RU-g  
else G5umeqYC  
break; 1.dX)^\  
} &#,v_B)a_E  
} iiN?\OO^~  
catch(IOException e){e.printStackTrace ();} gvr]]}h:O  
catch(Exception e){e.printStackTrace ();} sD2Qm  
*-7fa0<  
Nuq(4Yf1W  
Utility.log(nFileLength); *h])mqhB  
">,K1:(D  
Xj;2h{#s  
return nFileLength; `skH-lk,  
} VO|u8Z"  
J~'~[,K  
2%]t3\XW  
//保存下载信息（文件指针位置） 8J^d7uC  
private void write_nPos() GZ,j?@  
{ X&,N}9>B  
try{ Q'C4pn@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !p"Kd ~  
output.writeInt(nStartPos.length); 8xgc[#  
for(int i=0;i<nStartPos.length;i++) ku-cn2M/  
{ 8E=vR 8  
// output.writeLong(nPos); C\/b~HU  
output.writeLong(fileSplitterFetch.nStartPos); QU%N*bFW%P  
output.writeLong(fileSplitterFetch.nEndPos); 9JXhHAxD  
} *NF&Y  
output.close(); %0 qc@4  
} ^@Y9!G=  
catch(IOException e){e.printStackTrace ();} 9<w=),R`8  
catch(Exception e){e.printStackTrace ();} rNxG0^k(  
} i _8zjj7  
"d:.*2Z2  
Db
QBVy  
//读取保存的下载信息（文件指针位置） Sn0Xl3yr  
private void read_nPos() e00RT1L  
{ k|fh\F+$  
try{ nE^wxtY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ho>p ^p  
int nCount = input.readInt(); [e1\A&T  
nStartPos = new long[nCount]; pj j}K  
nEndPos = new long[nCount]; '%:5axg?]  
for(int i=0;i<nStartPos.length;i++) WEps.]s  
{ ^Jn|*?+l  
nStartPos = input.readLong(); 4fD`M(wv  
nEndPos = input.readLong(); <w;D$l}u  
} Ag<4r  
input.close(); ?'T"?b<  
} uH=Gt^_  
catch(IOException e){e.printStackTrace ();} H]U"+52h  
catch(Exception e){e.printStackTrace ();} rrbZ+*U  
} 2,+@#q  
0NVG"
-Q  
1RURZoL  
private void processErrorCode(int nErrorCode) q~mcjbLz  
{ ~;TV74~rr  
System.err.println("Error Code : " + nErrorCode); 
]}5`7  
} FV`3,NFk  
FU^Y{sbDg  
|%n|[LP'  
//停止文件下载 Qz'O{f  
public void siteStop() |_!PD$i-  
{ Lax9 "xI  
bStop = true; #3
YdjU3w  
for(int i=0;i<nStartPos.length;i++) |WQD=J%~(  
fileSplitterFetch.splitterStop(); pn+D@x#IA  
fQ^h{n  
Ua}g  
} 9tW3!O^_  
} 1a \=0=[  
//负责部分文件的抓取 Pxap;;\  
**FileSplitterFetch.java w6%l8+{R  
*/ gX/|aG$a!U  
package NetFox; qdKh6{  
4U_rB9K$  
~_(!}V
 
import java.io.*; bBd*}"v^"  
import java.net.*; Q,ZkeWQ7%  
rD_Ss.\^g  
D "JMSL4r  
public class FileSplitterFetch extends Thread { Z?5,cI[6#  
77)OW$G  
^!N;F"  
String sURL; //File URL y[TaM9<  
long nStartPos; //File Snippet Start Position ER0TY,  
long nEndPos; //File Snippet End Position N;%j#(v j  
int nThreadID; //Thread's ID ,q{lYX83S  
boolean bDownOver = false; //Downing is over BF@m)w.v  
boolean bStop = false; //Stop identical #1gTpb+t  
FileAccessI fileAccessI = null; //File Access interface 1t!&xvhG  
ch%Q'DR_I)  
8f5%xY$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0]f?Dx/8  
{ \UVT_=Y  
this.sURL = sURL; vbW\~xf  
this.nStartPos = nStart; :==UDVP  
this.nEndPos = nEnd; GA({ri  
nThreadID = id; J$o[$G_Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,:\zXESy4  
} 37GHt9l  
cj,&&3sbV  
}s8*QfK>  
public void run() Z3&XTsq  
{ aTmX!!  
while(nStartPos < nEndPos && !bStop) ?)i6:76(  
{ BN bb&]  
1K
fJl S+  
P2<gHJ9t  
try{ D| 3AjzW  
URL url = new URL(sURL); p1[WGeV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \J#I}-a&j  
httpConnection.setRequestProperty("User-Agent","NetFox"); :Map,]]B_  
String sProperty = "bytes="+nStartPos+"-"; 0l
l,V  
httpConnection.setRequestProperty("RANGE",sProperty); + xkMW%e<  
Utility.log(sProperty); G5C#i7cpm  
74</6T]^  
]}*G[[ ^p  
InputStream input = httpConnection.getInputStream(); ^^U)WB  
//logResponseHead(httpConnection); @5uyUSt]  
;1Tpzm  
mo97GW  
byte[] b = new byte[1024]; *;~{_Disz  
int nRead; *{L<BB^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (]GY.(F{  
{ m"ki*9]  
nStartPos += fileAccessI.write(b,0,nRead); vwSX$OZ  
//if(nThreadID == 1) c{r6a=C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {ILQ CvP*  
} Xqq?S  
l-JKcsM  
V3.vE,  
Utility.log("Thread " + nThreadID + " is over!"); dRarNW  
bDownOver = true; M\x7=*\  
//nPos = fileAccessI.write (b,0,nRead); P-*RN   
} *AJezhR  
catch(Exception e){e.printStackTrace ();} 3n=cw2FG  
} ~=aI2(b  
} )@};lmPR  
&vGEz*F  
NC#kI3{  
//打印回应的头信息 %QlBFl0a  
public void logResponseHead(HttpURLConnection con) ff2.|20  
{
omDi<-  
for(int i=1;;i++)
3]5&&=#  
{ d%"@#bB  
String header=con.getHeaderFieldKey(i); m/"=5*pA  
if(header!=null) :D)&>{?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ocuNrkZ  
Utility.log(header+" : "+con.getHeaderField(header)); }G0.Lq+a  
else `dq3=  
break; 4h0jX9  
} M@z_Z+q9  
} ps4Wwk(  
](( >i%%~  
^5iY/t~Q  
public void splitterStop() Aghj)V  
{ T[2f6[#[_  
bStop = true; d}A2I  
} |'>E};D  
t,as{.H{h  
L@x8hUG"  
} :j50]zLy{  
Z~.]ZWj-  
DG%%]  
/* pOe`*2[  
**FileAccess.java E* DVQ3~  
*//文件访问(定位，写)  z]R!l%`  
package NetFox; 6d?2{_},  
import java.io.*; M#gGD-  
@R Yb-d  
26klW:2*  
public class FileAccessI implements Serializable{ u\& [@v  
%BP)m(S7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eDMwY$J  
RandomAccessFile oSavedFile; 28L'7  
long nPos; 7ump:|  
"

u>sS  
8=_| qy}l/  
public FileAccessI() throws IOException kl<B*:RqH  
{ >[3,qP]E  
this("",0); l
PSDY&`P  
} GeW$lA I  
fbbl92p  
-W"0,.Dvg  
public FileAccessI(String sName,long nPos) throws IOException V<R+A*gY:  
{ XQoT},C  
oSavedFile = new RandomAccessFile(sName,"rw"); .j$bCKXGx  
this.nPos = nPos; d+| !6  
oSavedFile.seek(nPos); SbNUX  
} )|1JcnNSa  
x@RA1&c  
{~{s=c0  
public synchronized int write(byte[] b,int nStart,int nLen) +53zI|I  
{ K*i1! "w  
int n = -1; rH_:7#.E  
try{ |~vQ0D  
oSavedFile.write(b,nStart,nLen); HC`3AQ12!&  
n = nLen; \EfwS% P  
} Oh85*3  
catch(IOException e) zbKW.u]v  
{ VX@G}3Ck  
e.printStackTrace (); "+JwS  
} h+d;`7Z>  
\36;csu  
7%x+7  
return n; uM6!RR!~  
} V# %spW  
Xr6 !b:UX  
av$_hEjo|D  
} SX<mj  
Y>m=cqR  
8 =Lv7G%  
/* sN) .Jo  
**SiteInfoBean.java ;GEu.PdxB  
*/ y!D`.'  
package NetFox; s7.*o@G  
5K-)X9z?  
wef^o"aP  
public class SiteInfoBean { `ha:Gf
 
RL)3k8pk  
32FGDM  
private String sSiteURL; //Site's URL s;M*5|-  
private String sFilePath; //Saved File's Path %4KJ&R (>[  
private String sFileName; //Saved File's Name Oydmq,sVe(  
private int nSplitter; //Count of Splited Downloading File +B|X k[  
[$Bb'],k  
?i
=!UN  
public SiteInfoBean() lH>XIEj  
{//nSplitter的缺省值为5 N9|.D.#MF  
//default value of nSplitter is 5 w[G_w:$a  
this("","","",5); W)~.o/;  
} `v{X@x  
*c c+
Fd  
N6 8>`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vfDb9QP  
{ {xoo9jq-  
sSiteURL= sURL; j7+t@DqQ  
sFilePath = sPath;
bD-Em#>  
sFileName = sName; ?0%TE\I8  
this.nSplitter = nSpiltter; -{%''(G  
Y6PA\7Y\  
sZDJ+  
} i?=.; 0[|  
PCfs6.*5Mf  
5z>\'a1U  
public String getSSiteURL() {f3fc8(p  
{ l!` 0I] }  
return sSiteURL; EC&,0i4n:  
} =Q/>g6  
6|Q'
\  
-;-"i J0  
public void setSSiteURL(String value) "-:\-sMt{  
{ ljON_*  
sSiteURL = value; ='>UKy[=  
} BF
!zfX?n  
N+75wtLy&  
NyLnE  
public String getSFilePath() ,?/<fxIY  
{ ybO,~TQ  
return sFilePath; 2f4c;YS  
}  RZ%X1$  
&2igX?60  
LTct0Gh  
public void setSFilePath(String value) W10fjMC}^  
{ 1z:N$O_v  
sFilePath = value; Zx 1z hc  
} b15qy?`y  
.Tv(1HAc2l  
i8.[d5  
public String getSFileName() 
b{Ss+F  
{ H-w|JH>g  
return sFileName; vDvGT<d  
} V/e_:xECC  
AgJ~6tK  
V+z)B+  
public void setSFileName(String value) %Ege^4PE  
{ |hoZ:  
sFileName = value; `1]9(xwhQ0  
} V}-o):dI|  
-~f.>@Wb  
Ghc0{M<  
public int getNSplitter() q+~CA[H5K  
{ zmRK%a(  
return nSplitter; 3PffQ,c[~  
} p\S3A(  
hh&y2#Io  
{[*_HAy7  
public void setNSplitter(int nCount) zK?[dO  
{ ^i\1c-/  
nSplitter = nCount; v1)6")8o+  
} {E|gV9
g  
} ~#\#!H7  
Sw'?$j^3  
F2'cL@E3  
/* ?F{xDfqw  
**Utility.java 2zu~#qU[)M  
*/ KW^aARJ)  
package NetFox; IIiN1 Lu,5  
B$EP'5@b  
|0p'p$%  
public class Utility { &y\2:IyA  
ku8c
)  
V"iLeC  
public Utility() q(^J7M)  
{ f@L{*Upj+  
7+4"+C
A  
c\MDOD%9  
} V}+;bbUc-  
]i2\2MTW8  
//线程睡眠 5AU3s  
public static void sleep(int nSecond) vW3ZuB  
{ %$| k3[4V  
try{ %QLYNuG  
Thread.sleep(nSecond); [zE
P|  
} a=VT|CX[  
catch(Exception e) %nF\tVP3]  
{ *!@x<Hf<  
e.printStackTrace (); z-gG(  
} #SNI dc>9\  
} ;tiUOixJ  
r0 C6Ww7u  
//日志 *?Ef}:]  
public static void log(String sMsg) RQNi&zX/  
{ 5N<v'6&=  
System.err.println(sMsg); olh3 R.M<  
} ][#*h`I  
tdF[2@?+  
KB
A%  
public static void log(int sMsg) 'PYqp&gJ  
{ I.1l
  
System.err.println(sMsg); KdsvZim0>  
} 5>Yd\(`K  
} FH`&C*/F0Y  
7#qL9+G  
Hd`p_?3]  
/* ?^4sE-C6  
**TestMethod.java [:@?,?V\N  
*/ pY#EXZ#   
package NetFox; 2_b'mepV  
=2)t1 H  
vaJXX  
public class TestMethod { )0MshgM  
TFDCo_>o  
g@VndAp  
public TestMethod() x]cZm^  
{ ///xx/weblogic60b2_win.exe 5?0gC&WfN  
try{ [iy;}5XK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4 xzJql  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lILtxVBO2o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lNVAKwW2#  
fileFetch.start(); x`vs-Y:P  
} ]pTw]SK  
catch(Exception e){e.printStackTrace ();} U*"cf>dB(  
zb}+ m#q  
C-^%g[#  
} (H%d]  
4@iJ|l  
G2{M#H  
public static void main(String[] args) | 8Egw-f  
{ 15o *r  
new TestMethod();
`G0rF\[  
} &dDI*v+  
} "`*a)'.'^c  
点击下载更多相关资料