http断点续传简单实现（java)

/* h oL"
K  
**SiteFileFetch.java n{v[mqm^  
*/ |oI]  
package NetFox; $bT<8:g  
import java.io.*; 8<Yqpb  
import java.net.*; HOrD20  
nq"U`z@R  
0h",.  
public class SiteFileFetch extends Thread { 9H4NvB{  
7Eett)4  
xxC2F:Q?U  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9Jhc5G  
long[] nStartPos; //开始位置 ('7qJkV  
long[] nEndPos; //结束位置 #:n:3]t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BK16~Wl  
long nFileLength; //文件长度 [N4#R  
boolean bFirst = true; //是否第一次取文件 ^;]Q,*Q  
boolean bStop = false; //停止标志 ct#3*]  
File tmpFile; //文件下载的临时信息 )"Vd8*e  
DataOutputStream output; //输出到文件的输出流 ,Rh6(I  
\ZPmPu9^(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }Kc03Ue`%e  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8LM 91  
{ /MUa b*h  
siteInfoBean = bean; Ps!~miN|>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eL7\})!W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +Tug.[A  
if(tmpFile.exists ()) pN
^^U[  
{ pAd 8-a  
bFirst = false; Xitsbf=Gg  
read_nPos(); M@b:~mI[sw  
} J$X
{4  
else {"x8q  
{ +vh 4I  
nStartPos = new long[bean.getNSplitter()]; o> i`Jq&  
nEndPos = new long[bean.getNSplitter()]; W~e/3#R\=  
} Z}Ld!Byz  
xmI!N0eta  
O0VbKW0h3  
3"ii_#1  
} ya^zlj\`0e  
(s2ke  
c0%.GcF0{  
public void run() W%bzA11l  
{ p#eai  
//获得文件长度 B5iVT<:a  
//分割文件 ?i8a)!U  
//实例FileSplitterFetch qfQg?Mr  
//启动FileSplitterFetch线程 1:+
f@#  
//等待子线程返回 `x0GT\O2-  
try{ hH|m
oj]  
if(bFirst) ..g?po  
{ ,xeJf6es  
nFileLength = getFileSize(); ;$Q&2}L[  
if(nFileLength == -1) DiLZ5^`]  
{ [aF^D;o  
System.err.println("File Length is not known!"); mDT"%I"4j  
} <:rbK9MIl  
else if(nFileLength == -2) !b0ANIp  
{ U)n+j}vi  
System.err.println("File is not access!"); 1>BY:xZr  
} ^mA^7jB  
else np#RBy  
{ &2EimP  
for(int i=0;i<nStartPos.length;i++) k1
5B5
 
{ iVg3=R)[1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pl}>  
} n\ yDMY  
for(int i=0;i<nEndPos.length-1;i++) zFn-VEJ)  
{ '%2q'LqSA  
nEndPos = nStartPos[i+1]; `?fY!5BA  
} @6N$!Q?  
nEndPos[nEndPos.length-1] = nFileLength; ?pF7g$>q  
} .(7end<  
} ?7Y6: zo$^  
YFF\m{#  
{xzs{)9|Y4  
//启动子线程 yp}a&Dg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BmP!/i_  
for(int i=0;i<nStartPos.length;i++) EqV]/0-\  
{ v7ShXX:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OcBKn=8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |H LU5=Y  
nStartPos,nEndPos,i); xKl!{A9$w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YF]W<ZpY  
fileSplitterFetch.start(); k_^|%xJ  
} 7vRFF@eq}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t3dvHU&Z:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !G0O
D$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Sas&P:#r  
nEndPos = " + nFileLength); $i^#KZ}-WK  
// fileSplitterFetch[nPos.length-1].start(); 2th>+M~A  
aWe?n;  
;E"TOC  
//等待子线程结束 gg-4ce/  
//int count = 0; U0PQ[Y#\  
//是否结束while循环 VKjDK$  
boolean breakWhile = false; 91 ]"D;NN  
V@QWJZ"  
1${lHVx]  
while(!bStop) _.ny<r:g  
{ xzqgem`[\  
write_nPos(); U=<d
;2N#  
Utility.sleep(500); X~`<ik{q  
breakWhile = true; *Z+8L*k97  
b xU13ESv  
PW[NW-S`c  
for(int i=0;i<nStartPos.length;i++) `H_.<``>  
{ vUX(h.}8  
if(!fileSplitterFetch.bDownOver) \ nIz5J}3  
{ OqaVp/,  
breakWhile = false; b*7:{FXg  
break; 1Rrl59}5  
} I(cy<ey+e  
} kFJ sB,2-  
if(breakWhile) errT7&@,A  
break; OJkiTs{  
jP]I>Tq  
3kl<~O|Fs  
//count++; ^X&n-ui   
//if(count>4) rM sd)  
// siteStop(); [%8t~zg  
} rW~hFSrV[o  
eC9nOwp]xH  
Jj~c&LxrO  
System.err.println("文件下载结束！"); yK$.wd2,  
} M7\; Y  
catch(Exception e){e.printStackTrace ();} 1nt VM+  
} cVg!"  
_*xjG \!  
A[/_}bI|  
//获得文件长度 ,}("es\b  
public long getFileSize() x"n!nT%Z  
{ F|eKt/>e  
int nFileLength = -1; A@-A_=a,  
try{ YkPc&&#  
URL url = new URL(siteInfoBean.getSSiteURL()); MQ9Nn|4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (Hr_gkGtM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mn-f  
Qj?qWVapA  
-FAAP&LG  
int responseCode=httpConnection.getResponseCode(); Auq)  
if(responseCode>=400) 0X`sQNx  
{ }\9elVt'2  
processErrorCode(responseCode); "kE$2Kg  
return -2; //-2 represent access is error 3Ishe
"  
} +}XFkH~  
8IAf9  
zfAkWSY  
String sHeader; vS! TnmF  
k63]Qf=5?N  
+w(sDH~kd  
for(int i=1;;i++) ]6`]+&  
{ w3,1ImrXp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lw.4O^  
//Utility.log(in.readLine()); A,tmy',d"  
sHeader=httpConnection.getHeaderFieldKey(i); d!V;\w  
if(sHeader!=null) >O{U4_j@(  
{ ^!={=No]  
if(sHeader.equals("Content-Length")) i|z=q  
{ m.F \Mn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <.DFa/G   
break; kl0!*j  
} ;3nR_6\  
} l17sJ!I  
else dSD7(s!  
break; :YZqrcr}  
} MH"{N "|  
} $\W|{u`  
catch(IOException e){e.printStackTrace ();}  #E[{  
catch(Exception e){e.printStackTrace ();} 6D[m}/?Uy  
8{m5P8w'  
X=:|v<E   
Utility.log(nFileLength); xKilTh_.6  
-,M*j|  
M^i^_}~S;  
return nFileLength; _I("k:E7  
} 52*9q!  
EJdl%j  
`^rN"\  
//保存下载信息（文件指针位置） X1A~#w>  
private void write_nPos() X+'z@xpj  
{ NTnjVU }  
try{ =@98Gl9!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /rKdxsI*  
output.writeInt(nStartPos.length); 9WXJz;  
for(int i=0;i<nStartPos.length;i++) C q/936`O  
{ Q7 dXTS4H  
// output.writeLong(nPos); -~nU&$ccL  
output.writeLong(fileSplitterFetch.nStartPos); Hs%;uyI@$  
output.writeLong(fileSplitterFetch.nEndPos); jTo-xP{lC  
} j%2l%Mx(  
output.close(); P1<Y7+n  
} (*.t~6c?5  
catch(IOException e){e.printStackTrace ();} l?F&I.{J  
catch(Exception e){e.printStackTrace ();} :U
jF<V  
} PT9,R^2T!  
C~1
6Jj:v  
=%p%+F@RlW  
//读取保存的下载信息（文件指针位置） X[Lwx.Ly8  
private void read_nPos() !xU1[,9  
{ N;<.::x  
try{ d?j_L`?+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~0m
O<0~  
int nCount = input.readInt(); -`z`K08sT  
nStartPos = new long[nCount]; d)'am 3Q  
nEndPos = new long[nCount]; F %OA  
for(int i=0;i<nStartPos.length;i++) D1&%N{  
{ =j%B`cJ66_  
nStartPos = input.readLong(); 9<0p1WO  
nEndPos = input.readLong(); c:  /Wk  
} `+IB;G1  
input.close(); 6g/ <FM  
} 2>l =oXq  
catch(IOException e){e.printStackTrace ();} ~$#"'Tl4J  
catch(Exception e){e.printStackTrace ();} (dOC ^i  
} 1_D|;/aI  
`yjHLg  
]9xuLJ)  
private void processErrorCode(int nErrorCode) '@Zau\xC  
{ B8+J0jdg6%  
System.err.println("Error Code : " + nErrorCode); q Ee1OB  
} 8.-0_C*U;  
RC_w 1:h  
OYw~I.Rq  
//停止文件下载 4!'1o`8vs  
public void siteStop() c7$L:  
{ )7U^&I,  
bStop = true; sSisO?F!Z  
for(int i=0;i<nStartPos.length;i++) e:SBX/\j
 
fileSplitterFetch.splitterStop(); [dG&"%5vD  
Y\7>>?  
9:|z^r  
} <ptgFR+  
} m/,.3v  
//负责部分文件的抓取 @;%+Ms  
**FileSplitterFetch.java Eei"baw/  
*/ sFqLxSo_I  
package NetFox; cC{eu[ XW  
Ls8@@b,t2  
TO&ohATp  
import java.io.*; "O{_LOJ  
import java.net.*; nz72w_  
hE|Z~5\Y,>  
p.{M sn  
public class FileSplitterFetch extends Thread { V3%"z  
3;M7^DM  
<eU1E}BDQ  
String sURL; //File URL \Tf$i(0q  
long nStartPos; //File Snippet Start Position t')47k\  
long nEndPos; //File Snippet End Position i$~2pr  
int nThreadID; //Thread's ID  yN9k-IPI  
boolean bDownOver = false; //Downing is over 'H"wu /#  
boolean bStop = false; //Stop identical P5u Y1(  
FileAccessI fileAccessI = null; //File Access interface dGxk ql  
)tH.P: 1~,  
J~=bW\^I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +_.k\CRms  
{ :}QBrd  
this.sURL = sURL; BCDmce`=l  
this.nStartPos = nStart; $XBn:0U  
this.nEndPos = nEnd; tUS)1*{_  
nThreadID = id; ]V|rOtxb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3[R<JrO  
} H .F-mm  
zV)(i<Q  
W'aZw9  
public void run() UKYQ @m  
{ F32N e6Y6"  
while(nStartPos < nEndPos && !bStop) 8v$2*$  
{ XJx$HM&0M  
N?xZ]?T  
)e#KL$B)v  
try{ #BB,6E   
URL url = new URL(sURL); )gOVnA/M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lSMv9:N  
httpConnection.setRequestProperty("User-Agent","NetFox"); bve_*7
CEM  
String sProperty = "bytes="+nStartPos+"-"; 4*k>M+o/C4  
httpConnection.setRequestProperty("RANGE",sProperty); ~UrKyA  
Utility.log(sProperty); l@;UwnI  
#[|~m;K(w  
4@2<dw|*h  
InputStream input = httpConnection.getInputStream(); j7(sYo@x7  
//logResponseHead(httpConnection); {{hp;&x  
B,Pbm|U1  
U_s3)/'  
byte[] b = new byte[1024]; [i[*xf-B  
int nRead; 4?+K:e #F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @vsgm
z  
{ nWfzwXP>_  
nStartPos += fileAccessI.write(b,0,nRead); oXC|q-(C
 
//if(nThreadID == 1) bjn: e!}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #[ei/p  
} /_WAF90R?  
$Hw w  
%b
u$t,  
Utility.log("Thread " + nThreadID + " is over!"); C%2BDj  
bDownOver = true; {e'P*j  
//nPos = fileAccessI.write (b,0,nRead); ~lBb%M  
} |PGF g0li  
catch(Exception e){e.printStackTrace ();} g=Gd|  
} l ga%U~  
} 0ge"ISK  
[&_7w\m  
RIhu9W  
//打印回应的头信息 d=`a-R0  
public void logResponseHead(HttpURLConnection con) 968<yO]  
{ {6*$yLWK  
for(int i=1;;i++) \,UpFuU\  
{ {Ad4H[]|]  
String header=con.getHeaderFieldKey(i); gmdJ8$  
if(header!=null) pUcN-WA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /+V}.  
Utility.log(header+" : "+con.getHeaderField(header)); (/mR p  
else ?*oBevUnCY  
break; 6tx5{Xl-o  
} 4*AkUkP:T  
} Tu!2lHK;  
]=gNA  
tTjadnX  
public void splitterStop() fwF&V^Dy  
{ Mh=yIx</  
bStop = true; /M,C%.-  
} yL2sce[  
{GH0>
1&  
'99rXw  
} Zz,j,w0 Z  
d}RU-uiW  
O]-)?y/  
/* #EG W76 f  
**FileAccess.java dd+hX$,  
*//文件访问(定位，写) H{)DI(,Y^P  
package NetFox; YkN0,6  
import java.io.*; ^Z |WD!>`  
&i(\g7%U  
qjBF]3%t%  
public class FileAccessI implements Serializable{ p*NKM} ]I  
c-`'`L^J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }1xD*[W  
RandomAccessFile oSavedFile; Cs!z3QU  
long nPos; w"Q/ 6#!K  
1"\^@qRv#  
!:]/MpQ ?  
public FileAccessI() throws IOException {4F=].!
 
{ QZh#&Qf;  
this("",0); e2"<3  
} z|M+ FHl$  
q`Rc \aWB%  
.](~dVp%~  
public FileAccessI(String sName,long nPos) throws IOException @u>:(9bp  
{ gzMp&J  
oSavedFile = new RandomAccessFile(sName,"rw"); |e QwI&  
this.nPos = nPos; KgH_-REN  
oSavedFile.seek(nPos); 1 $m[#3  
} o8B$6w:_  
'bQjJRq!  
67tB8X  
public synchronized int write(byte[] b,int nStart,int nLen) h5o6G1ur  
{ ~D0e\Q(A  
int n = -1; EXF|;@-"  
try{ zhC#<  
oSavedFile.write(b,nStart,nLen); rq#\x{l  
n = nLen; h@2YQgw`  
} qg06*$%  
catch(IOException e) F
(;=^w  
{ e"d-$$'e  
e.printStackTrace (); NiSybyR$  
} _x`oab0@  
8{- *Q(=/  
V;LV),R?  
return n; 1CR
)1H  
} F"^/R  
Ja7yq{j  
\Dx;AKs  
} y$K[ArqX  
gWIb"l  
Im!fZg  
/* D[ v2#2  
**SiteInfoBean.java J1u&Ga  
*/ 1YtbV
3  
package NetFox; uPVO!`N3
 
0{'m":D9  
J$^"cCMr  
public class SiteInfoBean { 0sP*ChY5S  
N|2PW ~,  
&5y|Q?  
private String sSiteURL; //Site's URL rYCIU  
private String sFilePath; //Saved File's Path df)S}}#H  
private String sFileName; //Saved File's Name 
3Viz0I<%  
private int nSplitter; //Count of Splited Downloading File rqWD#FB=z  
@@z5v bs'{  
>c@jl  
public SiteInfoBean() Tr.u'b(  
{//nSplitter的缺省值为5 %BwvA_T'Q  
//default value of nSplitter is 5 M,vCAZ  
this("","","",5); ZK4d;oa",  
} 7
PbwCRg  
TtWWq5X|  
$/kZKoF{f  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fyF8RTm{  
{ gl~9|$ivj>  
sSiteURL= sURL; r'<!wp@  
sFilePath = sPath; ,Ma%"cWVC  
sFileName = sName; NtG^t}V  
this.nSplitter = nSpiltter; `D? &)Y  
q\
G7T{t$.  
O%1uBc  
} T(=Z0M  
V`4/oM`  
sZ>0*S  
public String getSSiteURL() 6Qn};tbnD  
{ ?s@=DDB\u  
return sSiteURL; blKF78  
} +F92_a4  
n >@Qx$-  
ROJ=ZYof  
public void setSSiteURL(String value) cKB1o0JsYJ  
{ @Yw>s9X  
sSiteURL = value; WCP2x.gb5  
} HP,{/ $i:  
4C }#lW9  
zwJ\F '  
public String getSFilePath() /[I#3|  
{ J%IKdxa  
return sFilePath; owzcc-g  
} !8*7{7  
}_oQg_-7e  
5i-VnG  
public void setSFilePath(String value) .|i/ a%J  
{ ig^x%!;  
sFilePath = value; ! JauMR  
} Zg3 /,:1  
eWr2UXv$  
hO2W!68
 
public String getSFileName() BU O8Z]  
{ "..I$R  
return sFileName; Ae* 6&R4  
} {Fvl7Sh  
!>:]k?$b  
g*;zVi  
public void setSFileName(String value) s]pNT1,  
{ LaYd7Oyf]  
sFileName = value; ^|(VI0KO  
} pB0 SCS*  
EGzlRSgO  
fLZ99?J  
public int getNSplitter() D%=j@  
{ 6J <.i  
return nSplitter; !8|?0>3)  
} K?Jo"oy7  
G%>{Z?!B  
]VaMulb4  
public void setNSplitter(int nCount) Uka(Vr:  
{ 0lU pil  
nSplitter = nCount; s)#TT9BbV  
} <=!FB8 .  
} "%w E>E  
U^kk0OT^  
EUbyQL  
/* P1&Irwb`  
**Utility.java O f]/tdPp  
*/ sZ0)f!aH:_  
package NetFox; 47)\\n_\z  
+o]J0Gu  
N j:W6? A  
public class Utility { = O|}R
 
Yv3P]6c.  
$ve*j=p  
public Utility() ft$!u-`  
{ A]MX^eY  
M4e8PRlI  
sj&1I.@,>  
} z8j7K'vV1  
PnH5[4&k  
//线程睡眠 L-
Mf{z  
public static void sleep(int nSecond) ri49r*_1  
{ 6('CB|ga  
try{ ~&WBA]w'+  
Thread.sleep(nSecond); *9US>mVy  
} |=[._VH1  
catch(Exception e) @xr}(.  
{ jP.dQj^j&  
e.printStackTrace (); =3=8oFx8  
}
C_&ZQlgQ  
} K@?K4o   
{a,U{YJ\H  
//日志 1aezlDc*  
public static void log(String sMsg) {[bB$~7Eu  
{ v7<r-<I[  
System.err.println(sMsg); t\O#5mo  
} g6@^n$Y  
*t`=1Ioj  
k/i&e~! \  
public static void log(int sMsg) xu@+b~C\  
{ .SDE6nvbW  
System.err.println(sMsg); MC1&X
'  
} @DKph!cr  
} x??H%'rP  
~BgNMO;|  
\^d
YmU  
/* K/$5SN1  
**TestMethod.java {Hz;*1?$k  
*/ T3t w.yh  
package NetFox; QG5c>Q  
,7;euV5X  
Wf=hFc1_@  
public class TestMethod { }^`5$HEi  
jSw>z`'#H  
<1<0odB  
public TestMethod() M&KJZ  
{ ///xx/weblogic60b2_win.exe /}S1e P6  
try{ EQX?Zs?C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q&esI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w}U'>fj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "5"{~3Gw^  
fileFetch.start(); <FwAV=}6p  
} cK75Chsu  
catch(Exception e){e.printStackTrace ();} SKo*8r   
5s<.
qDc  
N
~DO_^  
} C\*0621  
OKnpG*)u=g  
2 ;Q|h$n  
public static void main(String[] args) jWK>=|)=c  
{ [ub)`-6 u  
new TestMethod(); n66b(6"mO2  
} UW&K\P  
} Mr@{3do$  
点击下载更多相关资料