http断点续传简单实现（java)

/* '/M9V{DD88  
**SiteFileFetch.java nMm4fns  
*/ IlN: NS  
package NetFox; U[7 &   
import java.io.*; Sv3O${B|  
import java.net.*; `t[b0; 'OH  
0x BO5[w,Y  
-
#@l`kt  
public class SiteFileFetch extends Thread { Z 0&=Lw  
hK^(Y  
z5.Uv/n\1  
SiteInfoBean siteInfoBean = null; //文件信息Bean v2eLH:6  
long[] nStartPos; //开始位置 :jL>sGvBv  
long[] nEndPos; //结束位置 "?9rJx$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;B*im S10  
long nFileLength; //文件长度 wT\JA4  
boolean bFirst = true; //是否第一次取文件 'kBg3E$y  
boolean bStop = false; //停止标志 A1>fNilC9  
File tmpFile; //文件下载的临时信息 wO<.wPa`  
DataOutputStream output; //输出到文件的输出流 N)yCGo  
oVlh4"y#Lf  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） h pf,44Kg  
public SiteFileFetch(SiteInfoBean bean) throws IOException PgOOFRwP  
{ >u?m Bx
 
siteInfoBean = bean; +/O3L=QyJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (U@Ks )  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _EPfeh;  
if(tmpFile.exists ()) ;::]R'F[  
{ |m{u]9  
bFirst = false; zm>^
!j !  
read_nPos(); YoDL/  
} g{ ()  
else b5i ehoA  
{ EKu%I~eM  
nStartPos = new long[bean.getNSplitter()]; [G!#y  
nEndPos = new long[bean.getNSplitter()]; hp|.hN(kS]  
}
lV%oIf[OB  
CcCcuxtR  
M'gGoH}B+q  
s#Ayl]8r  
} zTBf.A;e7  
f4'WT
  
&|9K~#LVS  
public void run() a gkw)#  
{ 3uXRS,C  
//获得文件长度 Nyx)&T&I  
//分割文件 *jQ?(Tf  
//实例FileSplitterFetch '[WVP=M<XV  
//启动FileSplitterFetch线程 !d.bCE~  
//等待子线程返回 x-nO; L-2p  
try{ ^cDHC^Wm  
if(bFirst) j_3`J8WwF  
{ Rf4}((y7Y\  
nFileLength = getFileSize(); XoNBq9Iu  
if(nFileLength == -1) IL>VH`D  
{ ~a$h\F'6  
System.err.println("File Length is not known!"); {,+{,Ere  
} 8sus$:Ry  
else if(nFileLength == -2) _DouVv>  
{ Q{[l1
:  
System.err.println("File is not access!"); 6 2:FlW>  
} G!T_X*^q2U  
else ,>p1:pga  
{ aS! If>  
for(int i=0;i<nStartPos.length;i++) !i>d04u`%  
{ ]\Z8MxFD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Lv&9
s  
} 'fjo
uO  
for(int i=0;i<nEndPos.length-1;i++) [s{ B vn  
{ <N{wFvF  
nEndPos = nStartPos[i+1]; XCyU)[wY  
} vSnGPLl  
nEndPos[nEndPos.length-1] = nFileLength; (S~kNbIa  
} (b;Kl1Ql]  
} zC,c9b  
X$2f)
3  
zJ6""38Pr  
//启动子线程 %?hvN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y{KYR)  
for(int i=0;i<nStartPos.length;i++) q6PG=9d0B  
{ S4U}u l  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [H[L};%=j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uG$*DeZti  
nStartPos,nEndPos,i); 4mHk,Dd9,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $\+x7"pI  
fileSplitterFetch.start(); +70x0z2  
} h+R26lI1x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xf#+^cQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NDUH10Y:[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9.%t9RM^  
nEndPos = " + nFileLength); iE?yvtr8  
// fileSplitterFetch[nPos.length-1].start(); b>2{F6F  
ZkJLq[:cM  
Vq
UCcT  
//等待子线程结束 B*(BsXQLY  
//int count = 0; M5a&eO  
//是否结束while循环 @O`T|7v  
boolean breakWhile = false; uUiS:Tp]  
9=q&SG  
[l/!&6  
while(!bStop)  + \]-"  
{ sW-0G$,|  
write_nPos(); <Umr2Vw-  
Utility.sleep(500); K491
QXG  
breakWhile = true; Aydpr_lp  
;f~fGsH}e'  
%VGW]!QR  
for(int i=0;i<nStartPos.length;i++) Ld 0*)rI#  
{ '&+]85_&$  
if(!fileSplitterFetch.bDownOver) x2sKj"2?@  
{ 5T%2al,F`  
breakWhile = false; !w}b}+]GB  
break; j1;<3)%0  
} DRpFEWsm  
} >F>VlRg  
if(breakWhile) km*Y#`{  
break; hVz] wKP  
jGi{:}`lB  
O/U?Wq  
//count++; $q*a}d[Q  
//if(count>4) UEx13!iFo  
// siteStop(); "IB36/9
 
} A%2B3@1'q  
nE +H)%p  
cQ]c!G|a4  
System.err.println("文件下载结束！"); `Se2f0",  
} *u-$$@|y  
catch(Exception e){e.printStackTrace ();} n5%\FFG0M  
} 6J\ 2=c`  
.*f6n|  
BT&R:_:  
//获得文件长度 gD51N()s,  
public long getFileSize() q 'd]  
{ pSbtm74  
int nFileLength = -1; 2{.g7bO  
try{ PZQAlO,  
URL url = new URL(siteInfoBean.getSSiteURL()); zrqI^i"c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &l0K~7)b  
httpConnection.setRequestProperty("User-Agent","NetFox"); oN[}i6^,e  
.^M#BAt2  
%Z4*;VwQ  
int responseCode=httpConnection.getResponseCode(); 7~FHn'xt  
if(responseCode>=400) 4#}aLP  
{ er5!ne  
processErrorCode(responseCode); UOFb.FRP>  
return -2; //-2 represent access is error _  xym  
} ;:_AOb31N  
=%<, ^2o  
PJ;WNo8  
String sHeader; 5+11J[~{  
Lu{/"&)  
G^tazAEfo  
for(int i=1;;i++) :'B(DzUR  
{ SzIzQR93&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :Fm*WqZu  
//Utility.log(in.readLine()); >SLQW  
sHeader=httpConnection.getHeaderFieldKey(i); 
_}Qtx/Cg  
if(sHeader!=null) >O<a9wz  
{ {f\wIZ-K A  
if(sHeader.equals("Content-Length")) ?)J/uU2w  
{ \c<;!vkZ04  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U+*l!"O,  
break; $cIaLq  
} 4~3 n =
T*  
} L /:^;j`c  
else 6i-G{)=l  
break; \HbZ~I-  
} U+qyS|i  
} 
{ibu0  
catch(IOException e){e.printStackTrace ();} McN[  
catch(Exception e){e.printStackTrace ();} r}&&e BY f  
FJDC^@Ne  
J{^md
0l  
Utility.log(nFileLength); Mib.,J~  
eM_;rMCr}  
iAZ8Y/  
return nFileLength; !p/SX>NJ  
} i_Hm?Bi!F  
{PX&#,_  
J/'Fj?
 
//保存下载信息（文件指针位置） gkO^J{_@q  
private void write_nPos() ~1D^C |%  
{ 9c[X[Qc  
try{ W,NqevXo:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `X5!s  
output.writeInt(nStartPos.length); >U,&V%y  
for(int i=0;i<nStartPos.length;i++) ttUK~%wSx  
{ t*9 g
usmG  
// output.writeLong(nPos); I)V=$r{  
output.writeLong(fileSplitterFetch.nStartPos); g%l ,a3"  
output.writeLong(fileSplitterFetch.nEndPos); 'o6}g p)  
} ",3v%$>  
output.close(); 6w7;  
} Nna.NU1  
catch(IOException e){e.printStackTrace ();} kW)3naUf<  
catch(Exception e){e.printStackTrace ();} }ofb]_C,  
} g}v](Q  
l<w7 \a6  
o[cOL^Xd1  
//读取保存的下载信息（文件指针位置） La )M  
private void read_nPos() 9tJ0O5  
{ #0r~/gW  
try{ RbL?(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c 9f"5~  
int nCount = input.readInt(); r@3-vLI!u  
nStartPos = new long[nCount]; U}5fjY  
nEndPos = new long[nCount]; =}#yi<Lt  
for(int i=0;i<nStartPos.length;i++) JY2<ECO  
{ `jGeS[FhR  
nStartPos = input.readLong(); B^/MwD>%  
nEndPos = input.readLong(); wHbkF#[:i  
} a~7D4G  
input.close(); >t3_]n1e  
} VKl,m ;&N  
catch(IOException e){e.printStackTrace ();} )vS0Au^C~  
catch(Exception e){e.printStackTrace ();} RFL* qd4  
} e&;e<6l&{  
]0."{^ksL  
uK@d?u!`  
private void processErrorCode(int nErrorCode) EL`|>/
[J  
{ E%bhd4$G  
System.err.println("Error Code : " + nErrorCode); 6?F88;L  
} P)`^rJ6
 
YSeH;<'  
>`0U2K  
//停止文件下载 \W.CHSD  
public void siteStop() zuLW'a6F-
 
{ K khuPBd2  
bStop = true; rNq*z,  
for(int i=0;i<nStartPos.length;i++) KkZx6A)$u  
fileSplitterFetch.splitterStop(); M YF ^zheD  
/eQAGFG  
^wolY0p  
} S/XU4i:aV  
} :|s8v2am  
//负责部分文件的抓取 zG#5lzIu,  
**FileSplitterFetch.java F,
Q;sq  
*/ 3P6O]x<-?  
package NetFox; %3a-@!|1<  
>BbX:  
gS'{JZu2  
import java.io.*; 9,'m,2%W  
import java.net.*; Qb^G1#r@C  
ekhv.;N~  
3:x(2 A  
public class FileSplitterFetch extends Thread { A4tk</A  
pX_#Y)5  
@wcF#?J  
String sURL; //File URL 309
pl  
long nStartPos; //File Snippet Start Position O6hzOyNX@  
long nEndPos; //File Snippet End Position /xk7Z q  
int nThreadID; //Thread's ID pJ] Ix *M  
boolean bDownOver = false; //Downing is over 0(7 IsG=t  
boolean bStop = false; //Stop identical >}V?GK36  
FileAccessI fileAccessI = null; //File Access interface tVRN3fJH  
`3F#k[IR  
/Sj~lHh  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +]%S}<R  
{ T'5{p  
this.sURL = sURL; |Mq+QDTTw~  
this.nStartPos = nStart; G\gjCp?!  
this.nEndPos = nEnd; TN0KS]^A3  
nThreadID = id; rM7qBt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C#U(POA  
} qi4P(s-i
 
Mh7m2\fLbd  
yiZtG#6K{  
public void run() 0)WAQt\/  
{ _= v4Iz0  
while(nStartPos < nEndPos && !bStop) R])
Eg&  
{ AT"gRCU$4  
a!$kKOK  
>B{NxL3->  
try{ ~*Y#Y{  
URL url = new URL(sURL); FW|& iS$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X+;[Gc}(W  
httpConnection.setRequestProperty("User-Agent","NetFox"); >_?i)%+)  
String sProperty = "bytes="+nStartPos+"-"; W"Ip]LJ  
httpConnection.setRequestProperty("RANGE",sProperty); |qw0:c=7!  
Utility.log(sProperty); *2zp>(%  
cT'Bp)a  
N1~bp?$1  
InputStream input = httpConnection.getInputStream(); kZw"a*6  
//logResponseHead(httpConnection); wm`<+K  
-%`~3*L  
7S{qo&j'  
byte[] b = new byte[1024]; ^~H}N$W"-q  
int nRead; \(\a=
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .
==D?#bn  
{ XKjrS 9:  
nStartPos += fileAccessI.write(b,0,nRead); b&rBWp0#  
//if(nThreadID == 1) y*iZ;Bv j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zq};{~u(  
} ,{0Y:/T'  
Yqs=jTq`{  
:TQp,CEa  
Utility.log("Thread " + nThreadID + " is over!"); T3{O+aRt  
bDownOver = true; xWG@<}H  
//nPos = fileAccessI.write (b,0,nRead); "h+Z[h6T  
} k+h}HCzE  
catch(Exception e){e.printStackTrace ();} Uc tlE>X`  
} *$eH3nn6g  
} <Q|\mUS6  
f]NLR>$L}  
8oX1 F(R  
//打印回应的头信息 ]\M{Abqd{  
public void logResponseHead(HttpURLConnection con) VIp|U{  
{ <&E}db  
for(int i=1;;i++) =2p?_.|'  
{ (kxS0 ]=  
String header=con.getHeaderFieldKey(i); o,rF15  
if(header!=null) KR?;7*qF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,t`V^(PEq  
Utility.log(header+" : "+con.getHeaderField(header)); vvxxwZa=O  
else Nn05me"X  
break; W2
2S/s  
} +VUkV-kP  
} {lds?AuK  
2w.FC  
+M=h+3hw](  
public void splitterStop() Usf@kVQ  
{ wo`.sB&T  
bStop = true; 8:TX9`,  
} 7:UeE~uB:  
d7V/#34  
s 4`-mIa  
} G+c&e:ip<  
tYD8Y  
^OV; P[  
/* >eGg 1  
**FileAccess.java bbC@  
*//文件访问(定位，写) |xB`cSu(  
package NetFox; S F)$b  
import java.io.*; hY4#4A`I  
wC{sP"D  
']nI
a7  
public class FileAccessI implements Serializable{ NN4Z:6W5  
P#A,(Bke3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !4p{b f  
RandomAccessFile oSavedFile; Kki(A4;7F  
long nPos; JT 7WZc)  
hCQOwk#  
d8wGXNd7B  
public FileAccessI() throws IOException 8>C4w 5kF  
{ H9T~7e+  
this("",0); _A,_RM$Y  
} ;<FAcR  
%j&vV>2  
+-!3ruwSn  
public FileAccessI(String sName,long nPos) throws IOException d*6f,z2=  
{ :BxO6@>Xc  
oSavedFile = new RandomAccessFile(sName,"rw"); &;$uU  
this.nPos = nPos; 2U./ Yfk\  
oSavedFile.seek(nPos); =zn'0g,J4  
} dy6zrgxygP  
2? E;(]dQ  
!td!">r46e  
public synchronized int write(byte[] b,int nStart,int nLen) :I#.d7`uk  
{ ^(;x-d3  
int n = -1; oCCtjr  
try{ ROkwjw  
oSavedFile.write(b,nStart,nLen); C@qWour  
n = nLen; EE'2<"M  
} 4u5j 7`O  
catch(IOException e) ]O|>nT
a  
{ a?-Jj\q  
e.printStackTrace (); &eV5#Ph  
} B
e{@ L  
RC7F/|w.z  
Xq1#rK(  
return n; |)7K(R)(=  
} `he# !"  
Z.${WZW  
G!F
dTvx$  
} n~l
B
}  
_h1bVd-  
Sj ovL
@X  
/* x;
[)#>.'  
**SiteInfoBean.java :3M,]W]  
*/ |co#X8J  
package NetFox; %/2 ` u  
`*U@d%a  
e,OXngC  
public class SiteInfoBean { nDn+lWA=g  
gxhp7c182  
'N{1b_v?  
private String sSiteURL; //Site's URL <);j5)/  
private String sFilePath; //Saved File's Path /[6wm1?!  
private String sFileName; //Saved File's Name 'Ft81e)/  
private int nSplitter; //Count of Splited Downloading File XB'rh F8rl  
7}xQ4M\u$  
\0|x<~#j'  
public SiteInfoBean() HP*)^`6X  
{//nSplitter的缺省值为5 w(HVC  
//default value of nSplitter is 5 54z`KX 73  
this("","","",5); @C-dCC?  
} }<G ae
5  
(l
wV(M  
` ,T.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b#7nt ?`7p  
{ (B` NnL$  
sSiteURL= sURL; Z(:\Vj"  
sFilePath = sPath; (B\Kb4m  
sFileName = sName; y1 a%f.F`  
this.nSplitter = nSpiltter; `_yksh3zL4  

4"PA7 e  
@yGnrfr  
} !
o| ex+z;  
86%k2~L  
q!&:y7O8  
public String getSSiteURL() N_D=j6B  
{ }*XF- U  
return sSiteURL; mTH[*Y,  
} 70avr)OM  
C
dl"TZ<  
jGLmgJG-P  
public void setSSiteURL(String value) ~H''RzN  
{ y2%[/L:u~  
sSiteURL = value; em'3 8L|(  
} Q-, 4  
k&yBB%g  

tqA-X[^  
public String getSFilePath() oItC;T  
{ f$ /C.
E  
return sFilePath; g?1bEOA!  
} [GknE#p  
UHY)+6qt]  
{(-TWh7V  
public void setSFilePath(String value) *)r_Y|vg  
{ (q"S0{  
sFilePath = value; x^3K=l;N  
} }f> 81[^  
aQhT*OT{Q  
rDaiA
x&  
public String getSFileName() b0f6?s  
{ |{MFo)  
return sFileName; !h&h;m/c  
} jhG6,;1zMI  
lS;S:- -F  
\U]<HEc^  
public void setSFileName(String value) [HXd|,~_j-  
{ 2wU,k(F_  
sFileName = value; }`whg8 fZ  
} 'o]}vyz;  
l7ES*==&@0  
cmf*BkS  
public int getNSplitter() O,@QGUoA  
{ F[ ^ p~u{  
return nSplitter; *[nS
*D\:  
} }8.$)&O$^  
L-W*h  
_58&^:/^  
public void setNSplitter(int nCount) w#(E+s~}  
{ 99h#M3@!  
nSplitter = nCount; /\jRr7 Cd  
} @)ozgs@e  
} Wbmqf s  
PClwGO8'&  
f$nZogaQ  
/* I~ SFY>s  
**Utility.java 1\f8-:C  
*/ .:['&; k  
package NetFox; eF8um$t9  
bB.nevb9p  
:B/u>  
public class Utility { /4BYH?*  
aj+I+r"~  
1eqFMf  
public Utility() $>~4RXC  
{ kJXy)  
imS&N.*3m  
=>C3IR/  
} [Az^i>iH  
nRZ T~S4  
//线程睡眠 b|Ed@C  
public static void sleep(int nSecond) p t{/|P  
{ >>7m'-k%D  
try{ $_Lcw"xO  
Thread.sleep(nSecond); \4q1<j  
} e3&.RrA  
catch(Exception e) ZONe
}tv:  
{ VN4H+9E  
e.printStackTrace (); & V/t0  
} yw?UA  
} +QrbW  
9/GC8*+  
//日志  - zEQ/6  
public static void log(String sMsg) bDcWPwe  
{ @h\u}Ee  
System.err.println(sMsg); k3"Y!Uha:  
} W^nG\"T^  
q(@hYp#O"3  
{,m W7  
public static void log(int sMsg) l3/?,xn  
{ 9s6d+HhM  
System.err.println(sMsg); eYjr/`>O  
}  F_%&,"$  
} [.iz<Yh  
w0t||qj^>"  
2}R)0][W  
/* $
5l=&  
**TestMethod.java T%:W6fH7  
*/ ^RS`q+g  
package NetFox; |N>TPK&Xt  
?G!DYUK  
aq,?  
public class TestMethod { RnkrI~x  
xBcE>^{1.  
?\Jl] {i2  
public TestMethod() V5LzUg]  
{ ///xx/weblogic60b2_win.exe M>g\Y  
try{ RV:%^=V-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]^^mJt.Iv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y;XEC;PXD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S(*SUH  
fileFetch.start(); Q<pL5[00fD  
} 6j
tnH'E/  
catch(Exception e){e.printStackTrace ();} Ol]+l]  
{^ ^)bf|1'  
:>g*!hpb  
} DPZG_{3D  
B[O1^jdO  
#}!Ge  
public static void main(String[] args) c`&<"Us  
{ ON=6w_  
new TestMethod(); Hi<5jl  
} tcf>9YsOr  
} t|aBe7t7  
点击下载更多相关资料