http断点续传简单实现（java)

/* vE}>PEfA  
**SiteFileFetch.java ^lt;K{  
*/ Po ,zTz  
package NetFox; X;~3 U 9  
import java.io.*; y<Z-f.  
import java.net.*; rJ@yOed["b  
q1|! oQ  
X-Yy1"6m1  
public class SiteFileFetch extends Thread {
THFzC/~Q  
QJsud{ada  
|uT&M`7\{  
SiteInfoBean siteInfoBean = null; //文件信息Bean g[#4`Q<.  
long[] nStartPos; //开始位置 7QOQG:-  
long[] nEndPos; //结束位置 (_9cL,v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nVO|*Bnf)  
long nFileLength; //文件长度 @CxXkR  
boolean bFirst = true; //是否第一次取文件 e5"?ol0  
boolean bStop = false; //停止标志 ^Hdru]A$2  
File tmpFile; //文件下载的临时信息 JdP[ cN  
DataOutputStream output; //输出到文件的输出流 zFR=inI  
-C>q,mDJZ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )\!-n]+A  
public SiteFileFetch(SiteInfoBean bean) throws IOException na%DF@Rt#  
{ !6yyX}%o  
siteInfoBean = bean; 'ot,6@~x>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OYj4G?c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |%i|P)]  
if(tmpFile.exists ()) #S*@RKSE|7  
{ NV[_XXTv7  
bFirst = false; l6AG!8H  
read_nPos(); U&(TqRi,  
} uTX0lu;  
else ranlbxp2l  
{ GC<zL}  
nStartPos = new long[bean.getNSplitter()]; FtEmSKD  
nEndPos = new long[bean.getNSplitter()]; 7jf%-X  
} DKvNQ:fI>9  
f19~B[a  
9rCvnP=  
jP{W|9@(  
} @S-p[u  
cP]5Qz  
-f4>4@y  
public void run() t$*V*gK{  
{ hPM:=@N$  
//获得文件长度 ff1Em.  
//分割文件 )(aj  
//实例FileSplitterFetch Zl:Z31  
//启动FileSplitterFetch线程 }gfs  
//等待子线程返回 ~@v<B I
 
try{ ?)60JWOJ1  
if(bFirst) #wvmVB.5~  
{ :'t+*{ff  
nFileLength = getFileSize(); oD0N<Ln}  
if(nFileLength == -1) #U=}Pv~wM  
{ '(qVA>S  
System.err.println("File Length is not known!"); :kaHvf  
} Py3Y*YP  
else if(nFileLength == -2) 0VA$ Ige  
{ 4;_<CB  
System.err.println("File is not access!"); o|FY-+  
} IhRYV`:  
else RyJN=;5p  
{ [xrM){ItW  
for(int i=0;i<nStartPos.length;i++) fV\ eksBF  
{ L, k\`9bQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gLH#UwfJ  
} qXb{A*J  
for(int i=0;i<nEndPos.length-1;i++) HoFFce7o  
{ ]rhxB4*1  
nEndPos = nStartPos[i+1]; ;`TSu5/  
} ,J(+%#$UT  
nEndPos[nEndPos.length-1] = nFileLength; 3XOf-v:~  
} 4Y=sTXbFt  
} y*AB=d^  
h /.^iT  
B
!#F!Wk"  
//启动子线程 %U4w@jp  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ga%x(1U[&  
for(int i=0;i<nStartPos.length;i++) 7n_'2qY  
{ ZgXn8O[a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YTtuR`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ao%;!(\I%  
nStartPos,nEndPos,i); `2j \(N,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nCj_4,O  
fileSplitterFetch.start(); 9aE.jpN  
} e/h2E dY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?;//%c8,.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TDMyZ!d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f\Fk+)e@  
nEndPos = " + nFileLength); :=<0Z1S  
// fileSplitterFetch[nPos.length-1].start(); e2onR~Cf  
j.5;0b_L^  
9
Xr@ll  
//等待子线程结束 RZV8
{
  
//int count = 0; d+6 by,'  
//是否结束while循环 $c WO`\XM  
boolean breakWhile = false; o`!7~n  
\w]c<gM K  
|&>!"27;w  
while(!bStop) '+ 8.nN  
{ @k~_ w#  
write_nPos(); frYPC Irj  
Utility.sleep(500); 6]#\|lds1  
breakWhile = true; E8:4Z$|c  
*@C4~Zo  
N1O& fMz  
for(int i=0;i<nStartPos.length;i++) jv"^_1  
{ V&' :S{i  
if(!fileSplitterFetch.bDownOver) =t+{)d.w  
{ SSS)bv8m  
breakWhile = false; ^aW?0qsH  
break; _>/T<Db  
} NW$C1(oT  
} ice7J2r_  
if(breakWhile) &|:T+LVv$+  
break; zW@OSKq4  
|?t6h 5Mt"  
(f5v{S6b(  
//count++; e|L$e0  
//if(count>4) X@ljZ  
// siteStop(); CQq'x+{F  
} Tz=YSQy$9  
}x[d]fcC  
Dm3/i|Y  
System.err.println("文件下载结束！"); 3,snx4q (  
} pY3N7&m\:  
catch(Exception e){e.printStackTrace ();} l
Z3o3"  
} F^],p|4f  
xELnik_L2  
Kp|#04]  
//获得文件长度 . k6)  
public long getFileSize() H& #Od?  
{ H3#xBn>9  
int nFileLength = -1; >};6>)0  
try{ zEQ<Q\"1  
URL url = new URL(siteInfoBean.getSSiteURL()); u#+p6%?k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $Qm-p?f  
httpConnection.setRequestProperty("User-Agent","NetFox"); -zeodv7  
j15TavjGh  
^UF]%qqOn  
int responseCode=httpConnection.getResponseCode(); fs]9HK/@\  
if(responseCode>=400) ,tEvz  
{ 8Ee bWs*1  
processErrorCode(responseCode); 6zQ {Y"0  
return -2; //-2 represent access is error A%VBBvk  
} A2`QlhZ  
bb6 ~H  
;|2h&8yX(/  
String sHeader; sP0pw]!  
dBV^Khf J  
x 5u.D^  
for(int i=1;;i++) C +-<  
{ J,s)Fu\j@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $z7[RLu0!  
//Utility.log(in.readLine()); 9`8\<a'rU  
sHeader=httpConnection.getHeaderFieldKey(i); +[ _)i9a  
if(sHeader!=null) 8F$b/Z  
{ 67I6]3[Z  
if(sHeader.equals("Content-Length")) #\+TKK  
{ ASuxty  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I#Q Tmg.  
break; o:\RJig<  
} TtL2}Wdd.%  
} Jmb [d\ /D  
else q%4l!gzF3  
break; 4>4*4!KR}  
} v-85`h  
} ILUA'T=B0  
catch(IOException e){e.printStackTrace ();} dqMR<Nl&  
catch(Exception e){e.printStackTrace ();} q8:Z.<%8  
9T47U; _)  
4#5w^  
Utility.log(nFileLength); n9;+RhxA  
UarU.~Uqi  
^n@.  
return nFileLength; 2`#jw)dM;}  
} $'f<4  
bQ-5uFe~$B  
}b9#.H9  
//保存下载信息（文件指针位置） YyX/:1 sg>  
private void write_nPos() \TG!M]D:  
{ ]E66'  
try{ A9!gww  
output = new DataOutputStream(new FileOutputStream(tmpFile)); , #yE#8
 
output.writeInt(nStartPos.length); R v9?<]  
for(int i=0;i<nStartPos.length;i++) a;Ic!:L
 
{ {~yj]+Im  
// output.writeLong(nPos); PUB|XgQDY:  
output.writeLong(fileSplitterFetch.nStartPos); =*.Nt*;;  
output.writeLong(fileSplitterFetch.nEndPos); 4z-sR/d  
} 3G9YpA_}X  
output.close(); b#-5b%ON  
} pti`q)
 
catch(IOException e){e.printStackTrace ();} %3e}YQe)  
catch(Exception e){e.printStackTrace ();} \?[#>L4  
} 3,j)PKf ;  
M/5e4b  
Q? a&q0f  
//读取保存的下载信息（文件指针位置） :GC<U|p  
private void read_nPos() c=l 3Sz?  
{ (Rvke!"B  
try{ p\o=fcH%E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W[o~AbU  
int nCount = input.readInt(); a z 7Vy-  
nStartPos = new long[nCount]; UXvk5t1  
nEndPos = new long[nCount]; %T*lcg  
for(int i=0;i<nStartPos.length;i++) T0WB  
{ |U?5% L  
nStartPos = input.readLong(); yhe$A<Rl=  
nEndPos = input.readLong(); .~V0>r~my  
} :X[(ymWNE  
input.close(); 8uoFV=bj\  
} b r)oSw  
catch(IOException e){e.printStackTrace ();} @v9PI/c  
catch(Exception e){e.printStackTrace ();} ]GYO`,  
} cA"',N8!5  
lTPo2-j/eK  
P
Y: l  
private void processErrorCode(int nErrorCode) Wy%q9x]}  
{ QP|Ou*Qm)  
System.err.println("Error Code : " + nErrorCode); =+q9R`!L]  
} BVxg=7%St  
}cyHR1K  
RqW ZhHI1M  
//停止文件下载 Q7$
ILW-S  
public void siteStop() N<+ ><>9  
{ XOO!jnQu  
bStop = true; vm)&WEL!  
for(int i=0;i<nStartPos.length;i++) |XxA Fje  
fileSplitterFetch.splitterStop();
~$>l@> xX  
9^J8V]X  
nBL7LocvR  
} ~C< X~$y&  
} WO$PW`k  
//负责部分文件的抓取 W-%oj.BMA  
**FileSplitterFetch.java ^~0Mw;n&  
*/ B:5(sK  
package NetFox; w!)B\l^+c  
6\)61o_1|  
S#qd#Zk|Y  
import java.io.*; c&2ZjM  
import java.net.*; qIK"@i[ uq  
cD^n}'ej  
I,vy__sZ  
public class FileSplitterFetch extends Thread { 7/NXb  
oK@!yYv  
S =q.Y  
String sURL; //File URL 3q  
long nStartPos; //File Snippet Start Position [AQ6ads
)  
long nEndPos; //File Snippet End Position XF(I$Mxl6  
int nThreadID; //Thread's ID 0Fsz  
boolean bDownOver = false; //Downing is over pt;E~_  
boolean bStop = false; //Stop identical VO>A+vx3M  
FileAccessI fileAccessI = null; //File Access interface +Y,>ftN  
d8Jy$,/`?  
|c,":R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException STs~GOm-  
{ JpE4 o2  
this.sURL = sURL; zJ7vAL
  
this.nStartPos = nStart; `@ULG>   
this.nEndPos = nEnd; "aK3 ylz;  
nThreadID = id; DDn@M|*$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j$^3  
} K+xiov-r?  
a ^<W ?Z  
=:[Jz1M5  
public void run() WV!qG6\W  
{ Rj9z'?a9  
while(nStartPos < nEndPos && !bStop) )I{41/_YA  
{ 4x.'H18  
*PE1)bF  
X>EwJ"q#  
try{ Jt"0|+g|  
URL url = new URL(sURL); !>-cMI6E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0Psp/H%  
httpConnection.setRequestProperty("User-Agent","NetFox"); mq$'\c 9.  
String sProperty = "bytes="+nStartPos+"-"; -0PT(gx  
httpConnection.setRequestProperty("RANGE",sProperty); ~YOwg\w^  
Utility.log(sProperty); ;!&A  
B#AAG*Ai8  
|
r1\  
InputStream input = httpConnection.getInputStream(); n[lf==R  
//logResponseHead(httpConnection); Qn(e[ C6\  
C_=! ( @`8  
vL@N21u  
byte[] b = new byte[1024]; ?1i>b->  
int nRead; !Sfy'v.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R!;tF|]  
{ 8s pGDg\g  
nStartPos += fileAccessI.write(b,0,nRead); CL|t!+wU/  
//if(nThreadID == 1) _KC)f'Cx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Oga0CR_  
} }9t$Cs%  
IBb3A  
Q.#@xaX'{`  
Utility.log("Thread " + nThreadID + " is over!"); Q+)fI  
bDownOver = true; rA&|!1q"B  
//nPos = fileAccessI.write (b,0,nRead); mf6?8!O}>  
} aB"W6[  
catch(Exception e){e.printStackTrace ();} MFcN.M  
} ge:UliHJ  
} S*Scf~Qp  
T[B@7$Dp*  
aiGT!2  
//打印回应的头信息 2]C`S,)  
public void logResponseHead(HttpURLConnection con) #o_`$'>  
{ 6c>t|=Ss(  
for(int i=1;;i++) S{{D G  
{ vE7L> 7  
String header=con.getHeaderFieldKey(i); g4!zH};n  
if(header!=null) _,_>B8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o0&jel1a  
Utility.log(header+" : "+con.getHeaderField(header)); |Y|{9Osus  
else B;Ab`UX#t  
break; 5WgdgDb@L  
} DtG><g}[]  
} Fh9`8  
.,(bDXl?  
"AP''XNi  
public void splitterStop() He^+>XIam  
{ YUJlQ2e(  
bStop = true; {co(w 7  
} .cN\x@3-j  
(p26TN;*$5  
%h 6?/  
} )Xg,;^  
H>_ FCV8  
p{xO+Nx1a  
/* tiSN amvG1  
**FileAccess.java RxU6.5N  
*//文件访问(定位，写) YFOSv]w  
package NetFox; iJIPH>UMX  
import java.io.*; !/ TeTmo  
q0{KYWOvk  
GiJ|5"  
public class FileAccessI implements Serializable{ 3]WIN_h  
=_I2ek  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k-xh-&  
RandomAccessFile oSavedFile; RoSh|$JF  
long nPos; o1YX^-<[F  
'
x{g P?.  
<iunDL0  
public FileAccessI() throws IOException su/l'p'  
{ )Y}t~ Zfx  
this("",0); Gp'rN}i^  
} :,%
~rR  
7kx)/Rw\B  
cOcF 
VPQ  
public FileAccessI(String sName,long nPos) throws IOException p;`jmF   
{ >'wl)j$  
oSavedFile = new RandomAccessFile(sName,"rw"); eWS[|'dl  
this.nPos = nPos; KhAj`vOzK  
oSavedFile.seek(nPos); J?Brnf.  
} /c'3I  
wO&`3Q3~$  
^_#0\f  
public synchronized int write(byte[] b,int nStart,int nLen) \k/ N/&;  
{ oh:q:St  
int n = -1; vg"y$%  
try{ 5p}Y6Lc\j  
oSavedFile.write(b,nStart,nLen); v~e@:7d i  
n = nLen; j*nZ   
} 8PB(<|}u  
catch(IOException e) U:m[* }+<  
{ f
s+l  
e.printStackTrace (); (xpj?zlmM  
} =`[08  
=Ig'Aw$x  
(f^WC,  
return n; 2s>dlz  
} f9u^/QVS&  
-v.\CtpHv  
V.#,dDC@j  
} Ls)y.u  
l-xKfp`  
b|U&{I>TH  
/* cP%mkh_ri  
**SiteInfoBean.java Kj,C9  
*/ h!ZEZ|{  
package NetFox; EGL1[7It`  
ojU:RRr4l$  
~Z!!wDHS  
public class SiteInfoBean { }UJS*mR  
p0~=
 
9YRoWb{y  
private String sSiteURL; //Site's URL w~+5FSdH  
private String sFilePath; //Saved File's Path YMOy
6C  
private String sFileName; //Saved File's Name #-dfG
.*  
private int nSplitter; //Count of Splited Downloading File JUXIE y^  
n#t{3qzpD  
.ii9-+_  
public SiteInfoBean() l_GvdD  
{//nSplitter的缺省值为5 y}*rRm.:  
//default value of nSplitter is 5 ,L%\{bp5  
this("","","",5); x4fl=  
} l?v`kAMR
 
&cztUM(  
,}2yxo;i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H$TYp  
{ 0KO_bF#EB=  
sSiteURL= sURL; {I+
  
sFilePath = sPath; 6I GUp  
sFileName = sName; /1 lIV_Z  
this.nSplitter = nSpiltter; s `fIeP  
u,e'5,`N  
{$z)7s  
} H((! BRl  
</F@5*  
:W(3<D7\  
public String getSSiteURL() LWE[]1=  
{ nlJ~Q_E(  
return sSiteURL; o:B?gDM  
} . [DCL  
/3->TS  
qawb9Iud0  
public void setSSiteURL(String value) T-ID{
i  
{ ^_ <jg
0V  
sSiteURL = value; #mwV66'
H  
} R2WEPMH%  
T.O^40y  
N p9N
#m?  
public String getSFilePath() >FED*C4  
{ ?#?[6t  
return sFilePath; ks|[`FH  
} BqC, -gC  
S6CM/  
#TZf\0\!  
public void setSFilePath(String value) 9XWHr/-_@  
{ )w];eF0c  
sFilePath = value; ''Fy]CwH(  
} UH/)4Wg  
b);Pw"_2  
RaT(^b(  
public String getSFileName() n B4)%  
{ Y,EReamp  
return sFileName; dd1m~Gm  
} W$LaXytmak  
U;Z6o1G  
f"t\-ux.b  
public void setSFileName(String value) {o"X8  
{ IPmSkK  
sFileName = value; C{>@b:]p  
} It'hmwu#  
#~?Q?"  
.|Y2'TWQ  
public int getNSplitter() 'W>Bz,M6yo  
{ 6*,'A|t?y  
return nSplitter; -5,QrMM<  
} @w&VI6  
tu\;I{h=0  
h<H.8.o  
public void setNSplitter(int nCount) [.4R ,[U  
{ =g4^tIYq  
nSplitter = nCount; "3o{@TdU  
} wy6>^_z  
} 9,|{N(N<!  
pOP`n3m0  
UMR0S5`}  
/* >m='#x0>Y  
**Utility.java |_L\^T|6  
*/ !xm
vCH=2  
package NetFox; WccTR aq  
^$qr6+  
z-fP#.  
public class Utility { [uK*=K/v  
]-"~?  
s\ft:a@  
public Utility() $z,lq#zzl  
{ j<H`<S  
)W9W8>Cc5_  
@Ee{ GH^-  
} H59}d oKH  
:l>&5w;  
//线程睡眠 %UZ_wsY\  
public static void sleep(int nSecond)
z}\TS.  
{ 9bvzt8pc  
try{ vQB;a?)o  
Thread.sleep(nSecond); 2RXU75VY  
} =H&{*Ja  
catch(Exception e) 8 tMfh  
{ V`xZ4 i%L  
e.printStackTrace (); 19-|.9m(  
} T0BFit6  
} [kwVxaI  
,!+>/RlJ
 
//日志 m<L.H33'  
public static void log(String sMsg) rT$J0"*=  
{ l H:Y8j  
System.err.println(sMsg); gi!{y  
} 2mUq$kws  
SKf9 yS#  
ut z.  
public static void log(int sMsg) =" Q5Z6W  
{ lZoy(kdc  
System.err.println(sMsg); \.h!'nfF  
}
Xv;} !z  
} #xL^S9P  
>DX\^86x  
q\wT[W31@  
/* t.wB\Kmt\  
**TestMethod.java 1L722I@  
*/ &K2J$(.t  
package NetFox; .OFwGOL%  
,{wA%Oy,  
uk%C:4T  
public class TestMethod { *Y!'3|T  
;M{@|z[Nv  
j2O?]M  
public TestMethod() 9x;CJhX
 
{ ///xx/weblogic60b2_win.exe fNb2>1  
try{ heQ<%NIA"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N-* ^V^V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H]e%8w))0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sevaNs  
fileFetch.start(); p)l>bC?3  
} zK.%tx}+=k  
catch(Exception e){e.printStackTrace ();} bxX[$q  
&w\E*$  
I2G4j/c=z  
} ^8dd  
!Ld0c4  
JU^{!u  
public static void main(String[] args) Vk%[N>  
{ <vS J<WY  
new TestMethod(); b+/XVEsr  
} -I."= c%  
} N"-</kzV  
点击下载更多相关资料