http断点续传简单实现（java)

/* d OQU#5  
**SiteFileFetch.java sk5h_[tK  
*/ /. k4Y  
package NetFox; iSCv/Gb:,  
import java.io.*; \tc4DS  
import java.net.*; Uf}s6#  
U3}r.9/  
u]lf~EE  
public class SiteFileFetch extends Thread { Ghs{B8  
C!6?.\U/:c  
P:eY>~m<;  
SiteInfoBean siteInfoBean = null; //文件信息Bean q"7rd?r52  
long[] nStartPos; //开始位置 D(yU:^L  
long[] nEndPos; //结束位置 PHU#$LG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bS=aFl#  
long nFileLength; //文件长度 ] lE6:^V  
boolean bFirst = true; //是否第一次取文件 0>} FNRC  
boolean bStop = false; //停止标志 oKLL~X>!U  
File tmpFile; //文件下载的临时信息 dO =fbmK  
DataOutputStream output; //输出到文件的输出流 u[5*RTE
 
TcPYDAa  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5V;BimI  
public SiteFileFetch(SiteInfoBean bean) throws IOException b_+dNoB  
{ 9*pH[vH  
siteInfoBean = bean; 3J%(2}{y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4
E/Q+^?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); aKkL0D  
if(tmpFile.exists ()) 2I(b ad  
{ |75>8;  
bFirst = false; F)Oe
;z6  
read_nPos(); Z7a~M3VnZ  
} 2+y<&[A8U  
else r%\(5H f  
{ dtD)VNkBZ  
nStartPos = new long[bean.getNSplitter()]; R>f$*T  
nEndPos = new long[bean.getNSplitter()]; puEuv6F  
} sOQF_X(.x  
Q}zAC2@L  
Sqw:U|h\FS  
5$9g4  
} ye!}hm=w  
ZZ|a`U  
GvQKFgO6h  
public void run() Z7>pz:,  
{ AWsy9  
//获得文件长度 >1u!(-A  
//分割文件 tl5}#uJ  
//实例FileSplitterFetch Qa-]IKOs  
//启动FileSplitterFetch线程 ^'9:n\SKQ  
//等待子线程返回 !ZlBM{C  
try{ Jm0o[4  
if(bFirst) .hO) R.  
{ /E8{:>2  
nFileLength = getFileSize(); Jse;@K5y  
if(nFileLength == -1) CEbZj z|  
{ aly1=j  
System.err.println("File Length is not known!"); ^~\cx75D  
} >.'rN>B+  
else if(nFileLength == -2) Ldqn<wNnI  
{ =*<Cw?Gc  
System.err.println("File is not access!"); Xo^P=uf%  
} H5wzzSV!:B  
else {6}H}_(]  
{ \o}m]v i  
for(int i=0;i<nStartPos.length;i++) A9qbE  
{ 5A^$!q P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3jH-!M5
 
} 3,;;C(  
for(int i=0;i<nEndPos.length-1;i++) CRXIVver  
{ BOqu$f+  
nEndPos = nStartPos[i+1]; b7;`A~{9v  
} g>].m8DZ'  
nEndPos[nEndPos.length-1] = nFileLength; /*Xr^X6  
} Ed6k7  
} e\o>(is  
-36pkC 6 \  
LEu_RU?  
//启动子线程 k/'>,WE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dZ]['y%  
for(int i=0;i<nStartPos.length;i++) !Miw.UmPm  
{ _4~'K?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;.dyuKlI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), woI.
1e5  
nStartPos,nEndPos,i); V+04X
"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^xz*%2@  
fileSplitterFetch.start(); ~\uI&S5  
} R1A|g=kF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z''ITX)oG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $"#2hVO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <<#j?%  
nEndPos = " + nFileLength); ~%.<rc0  
// fileSplitterFetch[nPos.length-1].start(); oXW51ty  
#>[BSgW  
.r=F'i}-j*  
//等待子线程结束 b9 Gq';o  
//int count = 0;  }\ ^J:@  
//是否结束while循环 OH+kN/Fd  
boolean breakWhile = false; Lt8J^}kwl  
YC,)t71l{  

Wycood*  
while(!bStop) Nj~3FL  
{ ePD~SO9*  
write_nPos(); '+8`3['  
Utility.sleep(500); 4n}tDHvd  
breakWhile = true; <,:p?36  
Xu[(hT6  
L_ &`  
for(int i=0;i<nStartPos.length;i++) ^}VAH#c  
{ ph5rS<  
if(!fileSplitterFetch.bDownOver) CN(}0/  
{ [9c|!w^F  
breakWhile = false; c}$C=s5 h}  
break; l:'\3-2a  
} a%FM)/oI|T  
} 0-VC$)S  
if(breakWhile) J/T$.*X  
break; |:[ [w&R  
IXA3G7$)  
V$OZC;4  
//count++; cUB+fH<B2  
//if(count>4) >^odV ;^  
// siteStop(); =uG}pgh0  
} BNj@~uC{  
4ju=5D];  
7~f"8\  
System.err.println("文件下载结束！"); 
,\]`X7r  
} WciL zx/  
catch(Exception e){e.printStackTrace ();} )fGIe rS  
} 3 *g>kRMJ  
|L}1@0i  
q
cWY8sYf  
//获得文件长度 *PF}L%K(?  
public long getFileSize() x@aWvrL  
{ ,JU3w  
int nFileLength = -1; @Q%9b)\\  
try{ ,SZYZ 25  
URL url = new URL(siteInfoBean.getSSiteURL()); 7]J7'!Iz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CW+]Jv]"  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cu\6VnW_6  
$yoIz.?V  
8mh@C6U  
int responseCode=httpConnection.getResponseCode(); V1]QuQ{&s  
if(responseCode>=400) >@ :m#d  
{ [11D7L%1t  
processErrorCode(responseCode); =1SG^rp  
return -2; //-2 represent access is error C" 2K U*  
} rm5@dM@  

~c\iBk  
Hl*V i3bQU  
String sHeader; X{BS]   
tbm/gOBw  
;i>(r;ZM  
for(int i=1;;i++) tso\bxiU  
{ #*~3gMI{=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O,_k.EH  
//Utility.log(in.readLine()); Sdr,q9+__  
sHeader=httpConnection.getHeaderFieldKey(i); ZQ)vvD<  
if(sHeader!=null) v~AD7k2{8  
{ h2_A'  
if(sHeader.equals("Content-Length")) $*S&i(z  
{ k )=Gyv<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h~r&7G@[}  
break; jFH wu*  
} <KEVA?0>  
} 9H%dK^C  
else 9:4m@dguh-  
break; PZYVLUw `  
} dml,|k=  
} 6Q~(ibK
x  
catch(IOException e){e.printStackTrace ();} zS/1v+  
catch(Exception e){e.printStackTrace ();} RemjiCE0'  
h}n?4B~Gi  
M=t;t0  
Utility.log(nFileLength); j9g0k<eg  
4V7=VZ,@3  
Fu\!'\6  
return nFileLength; Zk<Y+!  
} ~(P\'H&(h  
,b,t^xX>)  
}Q-%ij2  
//保存下载信息（文件指针位置） ohlCuH3  
private void write_nPos() S '(K  
{ <o"2
z~gv  
try{ NhRKP"<CO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3( o~|%  
output.writeInt(nStartPos.length); V:h3F7  
for(int i=0;i<nStartPos.length;i++) 7Rl/F1G o}  
{ Tr$37suF  
// output.writeLong(nPos); c1}i|7/XSi  
output.writeLong(fileSplitterFetch.nStartPos); \o<&s{6L  
output.writeLong(fileSplitterFetch.nEndPos); .gs:.X)TG9  
} ;9)A+bD]  
output.close(); :)j& t>aP  
} 5{\;7(  
catch(IOException e){e.printStackTrace ();} N/8_0]Gf  
catch(Exception e){e.printStackTrace ();} &2//\Qz  
} CQh6;[\:  
39oI &D>8  
2bt).gGm  
//读取保存的下载信息（文件指针位置） fK;I0J  
private void read_nPos() aSH =|Jnc  
{ '~n=<Y  
try{ VdE$ig@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ey ?paT  
int nCount = input.readInt(); LR%P\~  
nStartPos = new long[nCount]; G4{TJ,~  
nEndPos = new long[nCount]; s&D>'J  
for(int i=0;i<nStartPos.length;i++) o!sHK9hvJ)  
{ 3 adF) mh  
nStartPos = input.readLong(); K?gO]T{6  
nEndPos = input.readLong(); ?a{>QyL  
} ,%$Cfu  
input.close(); Dy^A??A[E}  
} CooOBk  
catch(IOException e){e.printStackTrace ();} )@E'yHYO>  
catch(Exception e){e.printStackTrace ();} NzC&ctPk  
} 2O " ~k  
OJ,Z  
an,JV0  
private void processErrorCode(int nErrorCode) j38>5DM6L  
{ (/gMtIw  
System.err.println("Error Code : " + nErrorCode); Azag*M?  
} 3Nk )  
#p/'5lA&j  
3im2 `n  
//停止文件下载 of0hJR  
public void siteStop() r)Fd
3)e   
{ ,Laz515  
bStop = true; 4S*7*ak{  
for(int i=0;i<nStartPos.length;i++) L,*#  
fileSplitterFetch.splitterStop(); ?Y'r=Q{w  
R*>
EbOuI  
7U`8W\-  
} u!9bhL`  
} -< }#ImTN  
//负责部分文件的抓取 HVaKy+RU  
**FileSplitterFetch.java "-A@d&5.  
*/ 28=L9q   
package NetFox; :AM_C^j~ D  
=(Wl'iG   
QIu!o,B  
import java.io.*; nCPIpw,]M  
import java.net.*; pb}4{]sI  
;BjJ<?^{  
A]AM|2
D  
public class FileSplitterFetch extends Thread { 06fs,!Q@  
kf2e-)uUs  
T[]kun  
String sURL; //File URL <7yn:  
long nStartPos; //File Snippet Start Position *[0)]|r  
long nEndPos; //File Snippet End Position "7_qB8\  
int nThreadID; //Thread's ID hsHtLH+@  
boolean bDownOver = false; //Downing is over q($fl7}Y  
boolean bStop = false; //Stop identical g@IYD  
FileAccessI fileAccessI = null; //File Access interface rKr2 K'  
C^!ej"  
GN ?1dwI  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4{J'p19  
{ MD=VR(P?eq  
this.sURL = sURL; HK!Vd_&9,  
this.nStartPos = nStart; 6Rc%P)6  
this.nEndPos = nEnd; s&~.";
b  
nThreadID = id; aFVd}RO0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >W?7a:#,  
} j aq/]I7  

i"U<=~  
6v9A7
g;4.  
public void run() ]#Q'~X W  
{ =OU]<%  
while(nStartPos < nEndPos && !bStop) /e4#DH  
{ `-[+(+["  
{;j@-=pV  
{qkd63X  
try{ Lmw{ `R  
URL url = new URL(sURL); 
H-Z1i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |? l6S
 
httpConnection.setRequestProperty("User-Agent","NetFox"); 0A>Fl*  
String sProperty = "bytes="+nStartPos+"-"; A1nEp0%Y  
httpConnection.setRequestProperty("RANGE",sProperty); k7ODQ(*v  
Utility.log(sProperty); uSi/|  
j2"Y{6c  
J>Uzd, /  
InputStream input = httpConnection.getInputStream(); ;Z(~;D  
//logResponseHead(httpConnection); hr] :bR  
IfGQeynj  
K;_.WzWD=  
byte[] b = new byte[1024]; 3U73_=>=&  
int nRead; `nDgwp:b"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]kd )j  
{ Z2dy|e(c  
nStartPos += fileAccessI.write(b,0,nRead); * 5Y.9g3)Q  
//if(nThreadID == 1) KGI0|Z]n~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y~N,=5>j  
} ^v].mV/  
;qF#!
Kb5  
,3{z_Rax-  
Utility.log("Thread " + nThreadID + " is over!"); %Pb 5PIk4  
bDownOver = true; \4.U.pKY  
//nPos = fileAccessI.write (b,0,nRead); JyX7I,0  
} y`EcBf  
catch(Exception e){e.printStackTrace ();} @Pc]qu  
} )2P4EEs[  
} )A4WK+yD$z  
D~xUr)E  
*YFe  
//打印回应的头信息 b:}`O!UBw  
public void logResponseHead(HttpURLConnection con) _r}oYs%1  
{ !m#cn
eV  
for(int i=1;;i++) e,}]K'!t  
{ X]Emz"   
String header=con.getHeaderFieldKey(i); k]Y#-Q1p~  
if(header!=null) !t["pr\ ?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t/bDDV"  
Utility.log(header+" : "+con.getHeaderField(header)); ~{[~ =~\u  
else _=_]Yx  
break; X"W%(x`w  
} 0O>8DX  
} FV/X&u8~  
Y'n TyH  
Es kh=xA {  
public void splitterStop() $;_'5`xs  
{ 'r%`(Z{~  
bStop = true; ,XW6W&vR;  
} .e2u)YqA  
aho;HM$hjP  
EvMhNq~y5  
} X9nt;A2TU+  
WIo^=?%  
2;4Of~  
/* `OnN12`  
**FileAccess.java ke~O+]  
*//文件访问(定位，写) Y$EqBN  
package NetFox; ,{7wvXP  
import java.io.*; g?M\Z";  
~fs{Ff'  
FpfOxF6A3  
public class FileAccessI implements Serializable{ 2"nd(+QH  
/yIkHb^c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'oHtg @  
RandomAccessFile oSavedFile; Qg?^%O'  
long nPos; DJrE[wI  
SMgf(N3]  
i}RxTmG<  
public FileAccessI() throws IOException %Md;=,a:6  
{ ~LHG  
this("",0); ^MUtmzh  
} R|8)iW^  

TH)gW  
-U"(CGb5  
public FileAccessI(String sName,long nPos) throws IOException "VkraB.i  
{ 'HkV_d[li  
oSavedFile = new RandomAccessFile(sName,"rw"); " 9 h]P^  
this.nPos = nPos; uFb&WIo1  
oSavedFile.seek(nPos); vgHMVzxj  
} j*g5f  
&iL"=\#  
FbJlyWND  
public synchronized int write(byte[] b,int nStart,int nLen) `pm6Ts{,  
{ zfO0+fMH  
int n = -1; {?l#*XH;  
try{ .'p_j(uv  
oSavedFile.write(b,nStart,nLen); )fpZrpLXE  
n = nLen; D+N{'d?+  
} yu<sd}@  
catch(IOException e) -O\!IXG^  
{ XJC|6"n  
e.printStackTrace (); M2[;b+W9  
} EP'2'51  
8"LvkN/v^  
|JSj<~1ki  
return n; Obrv5%'  
} %rzC+=*;  
eFp4MD8?  
41^+T<+  
} 5K;jW  
c
# U!Q7J  
n87B[R  
/* F# y5T3(P  
**SiteInfoBean.java %/CCh;N#  
*/ +tkDT@ `  
package NetFox; #
Fl"#g$  
D1;H,  
PR|F-/o  
public class SiteInfoBean { * h!gjbi  
/=*h\8c~  
6x^#|;e>lI  
private String sSiteURL; //Site's URL [DC8X P5<  
private String sFilePath; //Saved File's Path !=3[Bm
G  
private String sFileName; //Saved File's Name \ty{KAc&  
private int nSplitter; //Count of Splited Downloading File 1\=)b< y  
eqb8W5h'  
|`1lCyV\tE  
public SiteInfoBean() 9i*t3W71]  
{//nSplitter的缺省值为5 -uIu-a]  
//default value of nSplitter is 5 KbQ UA$gL=  
this("","","",5); o|*ao2a  
} 5f(yF  
P hs4]!  
?{NP3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'X d_8.  
{ D>|m8-@]  
sSiteURL= sURL; eRKuy l  
sFilePath = sPath; 26.),a  
sFileName = sName; <^c?M[j  
this.nSplitter = nSpiltter; :hr% 6K7  
N DZ :`D  
umhg O.!  
} l\xcR]O  
m-Q!V+XQp  
tPBr{  
public String getSSiteURL() Tw*:Vw  
{ Sio^FOTD  
return sSiteURL; &TJMopVn  
} KX D&FDkF  
vikA  
XVr>\T4  
public void setSSiteURL(String value) xucrp::g  
{ .<7M4Z  
sSiteURL = value; tIn dve  
} B3|h$aKC  
+a1Or  
,' V
T75  
public String getSFilePath() J<hqF4z  
{ h,%`*Qg6  
return sFilePath; $WmB__  
} UdO(9Jc5^  
5:y\ejU  
[A~n=m5H  
public void setSFilePath(String value) m}Xb#NAF8  
{ &U*MLf83`  
sFilePath = value; lw+Y_;  
} )S?.YCv?  
dpAj9CX(  
h0**[LDH  
public String getSFileName() V /i~IG`h/  
{ zplAH!s5''  
return sFileName; 3DjlX*  
} cft/;Au{  
E~}@56ER}  
)R %>g-dw  
public void setSFileName(String value) M2Q*#U>6r  
{ Z4ekBdmCL  
sFileName = value; {7d(B1[1  
} b'AA*v,b  
+az=EF  
kPRG^Ox8e  
public int getNSplitter() 3R|UbG`  
{ 8O^<#lh  
return nSplitter; Rtywi}VV2  
} !LI 8Xk  
B`<a~V  
C"SG':  
public void setNSplitter(int nCount) 0*J},#ba$  
{ *ggai?  
nSplitter = nCount; C[ma!he  
} 4H9mKR  
} a~*wZJ  
2I[(UMI$7  
O[Y
c-4  
/* N({0"7  
**Utility.java PenkqDc}  
*/ 
S1I#qb  
package NetFox; R$m?aIN  
%\f<N1~*  
M o?y4X  
public class Utility { OC6v%@xa  
[,yYr  
-|DBO0q  
public Utility() 7lUnqX.  
{ pgw_F  
bHRRgR`,  
xL
ShMv}  
} X..<U}e
 
DCP B9:u  
//线程睡眠 eWGaGRem  
public static void sleep(int nSecond) "'3QKeM1  
{ jPIOBEIG  
try{ M@]@1Q.p  
Thread.sleep(nSecond); ':d9FzGKa  
} O0_kLH$.  
catch(Exception e) E#n=aY~u-  
{ kXN8hU}iq  
e.printStackTrace (); X?aj0# Q  
} ?_`X8Ok  
} ,1 ^IFBJ  
LV8{c!"  
//日志 y=&^=Zh[  
public static void log(String sMsg) \Lg{GN.  
{ 6<o2 0(?  
System.err.println(sMsg); 9jI5bi)  
} B=)tq.Q7  
tjJi|  
, Y^GQ`~#  
public static void log(int sMsg) SnVb D<  
{ IFbN ]N0  
System.err.println(sMsg); o(stXa  
} }qg.Go  
} 2gJkpf9JN  
"R0(!3  
]$)U~)T iW  
/* LMaY}m>  
**TestMethod.java GhR%fxe  
*/ i#I7ncX  
package NetFox; i#%!J:_=  
i:2eJ.  
!'(
QF9%Q  
public class TestMethod { r*g<A2g%  
{ewo-dva  
)sLXtV)nm6  
public TestMethod() }K|40oO5  
{ ///xx/weblogic60b2_win.exe _ykT(`.#  
try{ Rg7~?b-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C zxF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %b>Ee>rdD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y
s9'1+9  
fileFetch.start(); -d*je{c|  
} ^oDSU7j5,  
catch(Exception e){e.printStackTrace ();} 64l(ru<  
pwmH(94$0  
_
)MbvF  
} ]O0:0Z\  
/JQY_>@W  
ZDr&Alp)o  
public static void main(String[] args) u&r+ylbsI  
{ "f4atuuXa  
new TestMethod(); vJsx_i\i  
} I*0TI@Lo  
} =-;J2Qlg6  
点击下载更多相关资料