http断点续传简单实现（java)

/* Lr^xp,_n  
**SiteFileFetch.java W wE)XE  
*/ sHuz10  
package NetFox; +wSm6*j7=  
import java.io.*; )L!R~F C  
import java.net.*; s`J=:>9*  
C{Ug ?hVP  
]Yu+M3Fq  
public class SiteFileFetch extends Thread { acZHb[w  
StL[\9~:  
5jQP"^g  
SiteInfoBean siteInfoBean = null; //文件信息Bean =QfKDA  
long[] nStartPos; //开始位置 I3Lsj}69  
long[] nEndPos; //结束位置 O)|4>J*B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PQ]9xzOg[  
long nFileLength; //文件长度 (3h*sd5ly  
boolean bFirst = true; //是否第一次取文件 -],?kP  
boolean bStop = false; //停止标志 X
gKG\C=3  
File tmpFile; //文件下载的临时信息 weV#%6=5\  
DataOutputStream output; //输出到文件的输出流 S7/v,E  
mv.I.EL  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q$0%~`t
 
public SiteFileFetch(SiteInfoBean bean) throws IOException HdUW(FZ  
{ BznA)EK?@  
siteInfoBean = bean; --YUiNh
h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PL$F;d  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Pu*HZW3l
 
if(tmpFile.exists ()) \,gZNe&Vv  
{ }.) 43(>]  
bFirst = false; 4_I{Q^f  
read_nPos(); d`<^+p)oy  
} ]~Vu-@ /}  
else #ljg2:I+  
{ 9:i,WJO  
nStartPos = new long[bean.getNSplitter()]; (y=o]Vy  
nEndPos = new long[bean.getNSplitter()]; FTnQqDuT  
} [0ffOTy  
]C6[`WF  
idS RWa  
QeJ.o.m{  
} _1> 4Q%  
}!]x|zU.=  
Yb3f]4EH  
public void run() p}DF$k%`  
{ wV&f|JO0+  
//获得文件长度 +7<>x-+  
//分割文件 <lmJa#  
//实例FileSplitterFetch So*Wk "  
//启动FileSplitterFetch线程 @1&;R  
//等待子线程返回 Fg\| e%  
try{ \e8*vos  
if(bFirst) nYy}''l<  
{ KbdfSF$  
nFileLength = getFileSize(); *-
AAQ  
if(nFileLength == -1) ~1r*/@M[V  
{ >^f)|0dn)E  
System.err.println("File Length is not known!"); .S'fM]_#  
} ,e FQ}&^A  
else if(nFileLength == -2) 0 ;_wAk  
{ JX/4=..  
System.err.println("File is not access!"); _#D\*0J  
} d<Q+D1  
else +%qSB9_>N{  
{ QiE<[QP{g  
for(int i=0;i<nStartPos.length;i++) rKQASRF5*  
{ px}7If  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U?F^D4CV\  
} hY= s9\  
for(int i=0;i<nEndPos.length-1;i++) JM-ce8U  
{ -iDEh_pts  
nEndPos = nStartPos[i+1]; a5}44/%  
} 9^QYuf3O  
nEndPos[nEndPos.length-1] = nFileLength; wz*A<iU  
} #}!>iFBcH  
} r d6F"W  
Ls>u`hG  
8yWu{'G
 
//启动子线程 5\w=(c9A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .eabtGO,  
for(int i=0;i<nStartPos.length;i++) R=amKLD?  
{ =tc`:!$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \l]pe|0EW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %g0z)J  
nStartPos,nEndPos,i); #x5N{8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w38c  
fileSplitterFetch.start(); NB3Syl8g  
} XiRT|%j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?z@v3(b[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %O&m#)|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sUbz)BS#.  
nEndPos = " + nFileLength); :PD`PgQ  
// fileSplitterFetch[nPos.length-1].start(); (~7m"?  
Z<N&UFw7QJ  
P~\a)Szy  
//等待子线程结束 WS1&3mOd  
//int count = 0; prlyaq;4  
//是否结束while循环 G/fP(o-Wd  
boolean breakWhile = false; !2Xr~u7a  
r
v,NQZ  
6MQs \J6.  
while(!bStop) NF/Ti5y  
{ rwL=R,   
write_nPos(); %jZp9}h  
Utility.sleep(500); vLBee>$  
breakWhile = true; <84C tv  
5y%u
n  
{b|3]_-/  
for(int i=0;i<nStartPos.length;i++) yE.495  
{ ^Y{6;FJ  
if(!fileSplitterFetch.bDownOver) aYaG]&hb  
{ w>6"Sc7oc2  
breakWhile = false; M<A;IOpR+  
break; `J>E9p<  
} '&-5CpDUs  
} #QTfT&m+G}  
if(breakWhile) \!UF|mD^tG  
break; jr,&=C(  
~U"by_  
g
[EM]q,  
//count++; mq J0z4I}  
//if(count>4) vo(g0Au)  
// siteStop(); pcI&  
} M<{5pH(K  
qGpP,  
I|g@
W_  
System.err.println("文件下载结束！"); lh,ylh  
} ?w]"~   
catch(Exception e){e.printStackTrace ();} A6^p}_  
} E!zd(  
1V|< A  
Rwc[:6;fn  
//获得文件长度 I&TTr7  
public long getFileSize() "x#]i aDjf  
{ L_THU4^j  
int nFileLength = -1; dGbU{#"3s  
try{ 2^)D .&  
URL url = new URL(siteInfoBean.getSSiteURL()); c*x J=Gz6d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QKp+;$SE'  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^&+zA,aL,A  
7
tpAZ<{  
qri}=du&F  
int responseCode=httpConnection.getResponseCode(); Ws-6W!Ib%  
if(responseCode>=400) .'t (-eT,  
{ 2BoFyL*  
processErrorCode(responseCode); bz,Da  
return -2; //-2 represent access is error 2{A;du%&  
} ,|T*|2Gm  
M82.khm~jM  
{S5RK-ax  
String sHeader; L6|Hgrj-u  
= n+q_.A  
81GQijq  
for(int i=1;;i++) >_;kTy,  
{ Nb~,`bu,2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); + ,@ FxZl  
//Utility.log(in.readLine()); {0is wq'J  
sHeader=httpConnection.getHeaderFieldKey(i); BFBR/d[&  
if(sHeader!=null) m b%C}8D  
{ W(;x\Nc7  
if(sHeader.equals("Content-Length")) $|4cJ#;^L  
{ !oZQ2z~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %04:z77  
break; 0LetsDN7I  
} y;Qy"-)qb  
} D:=t*2-Iv  
else )l`1)Ea~  
break; h&)fu{   
} 3jvx2  
} r5t;'eCea  
catch(IOException e){e.printStackTrace ();} EzR%w*F>Q  
catch(Exception e){e.printStackTrace ();} B$cOssl  
kUNj4xp)  
M{C6rm|  
Utility.log(nFileLength); iI3v[S  
p86~~rvq[  
R'rTE  
return nFileLength; >%-Hj6%  
} !Tv?%? 2l  
CPVzX%=  
ZU=,f'bU  
//保存下载信息（文件指针位置） r eGm>  
private void write_nPos() ^'m\D;
 
{ *6:v}#b[  
try{ ^#]c0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?nQ_w0j  
output.writeInt(nStartPos.length); _b>F#nD,'%  
for(int i=0;i<nStartPos.length;i++) ):e+dt  
{ J!rY 6[t  
// output.writeLong(nPos); ?#d6i$  
output.writeLong(fileSplitterFetch.nStartPos); \I?w)CE@R  
output.writeLong(fileSplitterFetch.nEndPos); dVa!.q_3  
} DhZ:#mM{  
output.close(); e"]"F{Q  
} &=YSM.G  
catch(IOException e){e.printStackTrace ();} Yl$X3wi  
catch(Exception e){e.printStackTrace ();} m;dm|4L^  
} %B@!  

>^dyQyK  
$0_^=DEW  
//读取保存的下载信息（文件指针位置） v2d<o[[C  
private void read_nPos() ?-pi,O~(p  
{ BWWq4mdb{  
try{ zG_p"Z7,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _}D%iJg#  
int nCount = input.readInt(); KE<kj$  
nStartPos = new long[nCount]; .Y;b)]@f  
nEndPos = new long[nCount]; aYqm0HCT  
for(int i=0;i<nStartPos.length;i++) :pRF*^eU  
{ +#4]o }6G  
nStartPos = input.readLong(); tv0Ha A  
nEndPos = input.readLong(); 5L F/5`  
} [!EXMpq'  
input.close(); hR-K@fS%l'  
} yf!,4SUkU  
catch(IOException e){e.printStackTrace ();} zJ;Rt9<7-  
catch(Exception e){e.printStackTrace ();} nTPB,QE<  
} xq2V0Jp1u  
Pg`JQC|  
9CB\n  
private void processErrorCode(int nErrorCode) ;+sl7qlA4  
{ xOythvO  
System.err.println("Error Code : " + nErrorCode); t-WjL@$F/  
} -OrR $w|e  
o]<jZ_|gB  
vYdR ht\(  
//停止文件下载 n0Go p^3  
public void siteStop() Jy]Id*u9  
{ zCt\o  
bStop = true; y
gN>"eP  
for(int i=0;i<nStartPos.length;i++) pV7N byb4  
fileSplitterFetch.splitterStop(); Ry&q1j  
)>\4ULR83  
Oa! m  
} |m)kN2w  
} Y6
A;AmM8  
//负责部分文件的抓取 t0q_>T-kt  
**FileSplitterFetch.java OiF{3ae(  
*/ iwU[6A  
package NetFox; =Q-k'=6\  
);Z]SGd  
2:Q(Gl`<l  
import java.io.*; ;\qXbL7  
import java.net.*; P>(P2~$Y"  
qNxB{0(D  
VevNG*  
public class FileSplitterFetch extends Thread { }x:0os  
-p`L%xj\  
A?8\Y{FQ  
String sURL; //File URL FbAW_Am(  
long nStartPos; //File Snippet Start Position <C'Z H'p  
long nEndPos; //File Snippet End Position v`x|]-/M&  
int nThreadID; //Thread's ID g
\Ak;03n  
boolean bDownOver = false; //Downing is over 9C/MRmv`  
boolean bStop = false; //Stop identical "k:=Y7Dx  
FileAccessI fileAccessI = null; //File Access interface F)SPaC4  
]3ifdGk  
*nRNg
.i3D  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s5&=Bsv  
{ (Sv>NQp  
this.sURL = sURL; io
.]'">  
this.nStartPos = nStart; px=]bALU  
this.nEndPos = nEnd; E)W@{?.o#  
nThreadID = id; o_f-GO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )6-9)pH@)  
} F}36IM9/:  
9pLg+6O  
~jN
'J+_$  
public void run() eh(<m8I  
{ sZg6@s=  
while(nStartPos < nEndPos && !bStop) A_R!uRD8-  
{ ys8Q.oBv_`  
E7nFb:zlV  
_w!a`w*3  
try{ ;hHi@Z9  
URL url = new URL(sURL); l+'F_a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xq[Yg15d%  
httpConnection.setRequestProperty("User-Agent","NetFox"); mrM4RoO  
String sProperty = "bytes="+nStartPos+"-"; Qhn;`9+L  
httpConnection.setRequestProperty("RANGE",sProperty); fvqd'2 t  
Utility.log(sProperty); })Yv9],6  
P`(Mk6gE  
lr~0p
L  
InputStream input = httpConnection.getInputStream(); 0 )}$^TV  
//logResponseHead(httpConnection); X(*!2uS  
L(G92,.  
?mv:neh  
byte[] b = new byte[1024]; IRW^ok.'b!  
int nRead; V5p0h~PK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t Rm+?  
{ s^hR\iY  
nStartPos += fileAccessI.write(b,0,nRead); eGL<vX  
//if(nThreadID == 1) tg\|?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RLVATM5  
} lG:kAtx4  
!L$x:/R9M  
)OP){/   
Utility.log("Thread " + nThreadID + " is over!"); 8e&p\%1  
bDownOver = true; Kz?#C  
//nPos = fileAccessI.write (b,0,nRead); s{}]D{bc  
} @Jn!0Y1_3  
catch(Exception e){e.printStackTrace ();} skg|>R,kE  
} n V&cC  
} Bp?  
&7>zURv  
56}X/u  
//打印回应的头信息 $B(kZ  
public void logResponseHead(HttpURLConnection con) 33Az$GXFsq  
{ 2C=Q8ayvX  
for(int i=1;;i++) @'6"7g  
{ /=:j9FF  
String header=con.getHeaderFieldKey(i); C! 9}  
if(header!=null) ztll}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5B4Ssrs5W~  
Utility.log(header+" : "+con.getHeaderField(header)); p3(2?UO!  
else *ZrSiIPP  
break; !t#F/C  
} xHA0gZf  
} Fc6iQ  
'b&yrBFD  
3=mr "&]r:  
public void splitterStop() 8LzBh_J?  
{ u<xo/=Z  
bStop = true; =r2]uW9  
} I/6)3su%  
N2C7[z+l`  
hz:pbes  
} M@et6aud;K  
8\.b4FNJ  
Yk!/ow@.  
/* 0RFRbi@n(  
**FileAccess.java Xf[kI  
*//文件访问(定位，写) }H> ^o9  
package NetFox; !69&Ld  
import java.io.*; Q\ppfc{,  
Yf@e=:  
KqY["5p  
public class FileAccessI implements Serializable{ !]yO^Ob.E  
M5357Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Pe73g%  
RandomAccessFile oSavedFile; o\b-_E5"?  
long nPos; Qn@Pd*DR  
B;>{0 s  
tJViA`@x  
public FileAccessI() throws IOException /D&%v*~E  
{ <EO$]>;0  
this("",0); w'MGA  
} Mn1Pt
|_@!  
)SF}2?7e  
 ^zzP.  
public FileAccessI(String sName,long nPos) throws IOException c/N@zum,{  
{ }o4N<%/+  
oSavedFile = new RandomAccessFile(sName,"rw"); EP'h@zdz  
this.nPos = nPos; i':ydDOOHA  
oSavedFile.seek(nPos); e
}/Lk5q!  
} Q1d'~e  
. o7m!  
gI^oU4mq  
public synchronized int write(byte[] b,int nStart,int nLen) )a9 ]US^  
{ Unj.f>U  
int n = -1; ^k5ll=}  
try{ *_a@z1  
oSavedFile.write(b,nStart,nLen); %~L>1ShtU  
n = nLen; AjcX  N  
} |(5W86C,ju  
catch(IOException e) k.("3R6v:  
{ \PDd$syDA  
e.printStackTrace (); fkf1m:Ckh  
} Bjk]ZU0T  
pyLRgD0 g  
O5$/55PI  
return n; G'3qzBJ#  
} 3vcO!6Z5  
_^Mx>hb4.  
M@ed>.  
} S
*j6OwZ
 
0#w?HCx=  
@-UL`+  
/* nKW*Y}VO  
**SiteInfoBean.java -@T/b$]'n  
*/ W
VVJ  
package NetFox; T,| 1g6  
b Q]/?cCYV  
XsnF~)YW  
public class SiteInfoBean { M\yT).>z  
aW>6NDq(  
^Z~;4il_F  
private String sSiteURL; //Site's URL CPNL 94x  
private String sFilePath; //Saved File's Path jqPkc28  
private String sFileName; //Saved File's Name B
6wRg8  
private int nSplitter; //Count of Splited Downloading File C@th O  
z5)s/;Sc  
d&Ef"H  
public SiteInfoBean() MEwo}=B  
{//nSplitter的缺省值为5 &|/| ''A)  
//default value of nSplitter is 5 0
GJn_@hr  
this("","","",5); 3B1cb[2y  
} ^^5&QSB:'  
8Y5  
v{}#?=I5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) In`mtn q  
{ ]Kr `9r),  
sSiteURL= sURL; 4~B> 9<$e>  
sFilePath = sPath; c%=IL M4  
sFileName = sName; OKoan$#sn  
this.nSplitter = nSpiltter; OE}*2P/M>  
dd]/.Z  
l
sJnI|  
} !?|Th5e  
CiB%B`,N  
,?L2wl[  
public String getSSiteURL() lbpq_=  
{ V0)fZS@tf  
return sSiteURL; $m42:amM  
} #5V9oKM  
I'|$}/\`  
g]*#%Xa  
public void setSSiteURL(String value) iezO9`  
{ Y.*y9)#S6  
sSiteURL = value; \EVBwE,  
} Hla0 5N' 4  
'0FhL)x?"T  
8 XU1/i7N  
public String getSFilePath() J>\B`E  
{ V3"=w&2]K  
return sFilePath; |`cKD >  
} SLh(9%S;  
o_'p3nD  
&}A[x1x06)  
public void setSFilePath(String value) uuQ(&  
{ ^/r7@:  
sFilePath = value; l(02W  
} rwI  
rnF/H=I/  
Bro9YP4<  
public String getSFileName() uXKERzg  
{
[Nk3|u`h  
return sFileName; ?:)
]h c  
} l?Ya"C`FL  
PS[+~>%  
% ClHCoyA  
public void setSFileName(String value) $fzaPD4.  
{ :AE&Ny4  
sFileName = value; `b^Ru+(dM  
} 4y+< dw  
Y 1t\iU  
@w?P7P<O`  
public int getNSplitter() }yz (xH  
{ bLwAXW2K+  
return nSplitter; 3J5!oF{H  
} K2<9mDn&  
|g//g\dd  
%;rHrDP(>  
public void setNSplitter(int nCount) RR]CW  
{ EUxGAj$-  
nSplitter = nCount; ^G.B+dG@`x  
} /%;mqrdk  
} &8vCZN^  
|%' nVxc4r  
, T8>}U(  
/* *exS6@N]  
**Utility.java ;oy-#p>N%  
*/ zc;|fHW~O  
package NetFox; 2u5|8  
iLkZ"X.'|1  
{qN 5MsY  
public class Utility { Ro9tZ'N!S  
j
'HZ\_  
<c2'0I >  
public Utility() G1o3l~x  
{ 3GUZ;jdn  
C,v(:ZE$J7  
pP*a  
} T-U}QM_e  
]3X@_NYj  
//线程睡眠 m>MB7,C;N  
public static void sleep(int nSecond) Yi$vg  
{ *U P@9D  
try{ v#U"pn|M  
Thread.sleep(nSecond); v%iof1 T'  
} N-e @j4WU  
catch(Exception e) Yq%9M=#k  
{ 4X+ifZO  
e.printStackTrace (); i?
 K|TC`  
} xUa{1!Y8  
} 0 g?z&?  
*%S"eWb  
//日志 LC'{p  
public static void log(String sMsg) XYZ4TeW\1  
{ @CZT  
System.err.println(sMsg); NbU[l  
} fvdU`*|n)  
J 
/f  
".<DAs j  
public static void log(int sMsg) 6{^E{go  
{ {;:/-0s  
System.err.println(sMsg); )C(?bR  
} &QGdLXOn  
} 93` AWg/T  
98uV6b~g  
\ywXi~+kUv  
/* iC98_o_9  
**TestMethod.java f;xkT  
*/ y&?
6FY  
package NetFox; SBIj<Yy]  
Zw ^kmSL"  
!AKg m'Nw  
public class TestMethod { oaoU _V  
/ ;,Md,p  
\\u<
S=G  
public TestMethod() >76\nGO  
{ ///xx/weblogic60b2_win.exe OeS\7  
try{ bqnNLs<N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C i
hAU"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t\%HX.8[;%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S'_-G;g.  
fileFetch.start(); 7:)n$,31FW  
} s3R(vd  
catch(Exception e){e.printStackTrace ();} %sX$nmi3  
}L#_\  
r0,:J  
} Fpa_qjL;  
.7.b:Dn0  
|!"`MIw,  
public static void main(String[] args) 06N}k<10O  
{ vfE6Ggz  
new TestMethod(); G}:lzOlMH  
} g'V>_u#(  
} *22nVKi{  
点击下载更多相关资料