http断点续传简单实现（java)

/* <'B^z0I,  
**SiteFileFetch.java A+l"  
*/ }rQ*!2Y?  
package NetFox; G
`P+J  
import java.io.*; ;8v5 qz  
import java.net.*; ( 0h]<7  
i~9)Hz
;!  
Cn<kl^!Q-  
public class SiteFileFetch extends Thread { |S8pq4eKJ_  
C,]Ec2  
8(I"C$D!k  
SiteInfoBean siteInfoBean = null; //文件信息Bean z?a
DOh  
long[] nStartPos; //开始位置 @gj5'  
long[] nEndPos; //结束位置 NAU<?q<)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Xo5L:(
?K  
long nFileLength; //文件长度 i,HAXPi  
boolean bFirst = true; //是否第一次取文件 ,@;<u'1\G  
boolean bStop = false; //停止标志 [y:LA~q  
File tmpFile; //文件下载的临时信息 \'KzSkC8  
DataOutputStream output; //输出到文件的输出流 QezK&iJg  
?l(hS\N,  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zN:752d^+r  
public SiteFileFetch(SiteInfoBean bean) throws IOException Cf N; `  
{ <>Im$N ai  
siteInfoBean = bean; ,rdM{ r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G~]BC#nB_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1%+
^SR72  
if(tmpFile.exists ()) D5p22WY  
{ FN R& :  
bFirst = false; gkdjH8
(2  
read_nPos(); o(zg_!P  
} L}mhMxOTi  
else x9e 9$ww}  
{ vKC>t95  
nStartPos = new long[bean.getNSplitter()]; d0
^2<  
nEndPos = new long[bean.getNSplitter()]; 'yNp J'  
} P:vy  
O+N-x8W{  
<gy'@w?  
0d2%CsMS"D  
} tF
QFpbI  
z|2liQrf+  
KOQTvJ_#  
public void run() Bz{ g4!ku  
{ /b|sv$BN  
//获得文件长度 xpk|?/6  
//分割文件 {;zPW!G  
//实例FileSplitterFetch 4
l*&3Ar  
//启动FileSplitterFetch线程 v+G:,Tc"  
//等待子线程返回 ;GAYcVB  
try{ W#[!8d35$  
if(bFirst) f/x "yUq  
{ 1
W u  
nFileLength = getFileSize(); y ^\8x^E
g  
if(nFileLength == -1) LcXMOT)s  
{ 'w2;oO  
System.err.println("File Length is not known!"); &}cie"\L  
} DbN'b(+  
else if(nFileLength == -2) (AYD@  
{ 4=Ey\Px  
System.err.println("File is not access!");
1|VJND  
} NP8TF*5V  
else /HRaX!|E#  
{ 0FOf *Lz  
for(int i=0;i<nStartPos.length;i++) ?MH4<7?"  
{ )YFs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1%,Z&@^j  
} l_c?q"X  
for(int i=0;i<nEndPos.length-1;i++) lu_Gr=#O  
{ CkU=0mcY  
nEndPos = nStartPos[i+1]; : [y(<TLw  
} m"R(_E5  
nEndPos[nEndPos.length-1] = nFileLength; g8Z14'Ke  
} 8##jd[o&p~  
} ^U}0D^jDeE  
o[#a}5Y  
>gl.(b25C  
//启动子线程 (zBQ^97]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z3dd9m#.]  
for(int i=0;i<nStartPos.length;i++) B/OO$=>(  
{ V1.F`3h~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )a\h5nQI)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +b+sQ<w?.  
nStartPos,nEndPos,i); ~<aB-.d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7&4,',0VL  
fileSplitterFetch.start(); L|LTsRIq  
} :!$z1u8R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ">3@<f>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +0Gep}&z.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Kcl$|T  
nEndPos = " + nFileLength); #A;Z4jK  
// fileSplitterFetch[nPos.length-1].start(); YkX=n{^  
zwtsw[.  
]B4mm__  
//等待子线程结束 UD{/L"GG  
//int count = 0; iC-ABOOu{l  
//是否结束while循环 4:$>,D\  
boolean breakWhile = false; B! V{.p  
Q\L5ZJ%y/  
fXe-U='  
while(!bStop) ak`)>  
{ gf?^yP ;V  
write_nPos(); : qRT9n$  
Utility.sleep(500); ;L2bC3
  
breakWhile = true; LltguNM$  
pm\X*t}L  
}eM<A$J  
for(int i=0;i<nStartPos.length;i++) moR2iyO_  
{ Ib!rf:  
if(!fileSplitterFetch.bDownOver) RWFf-VA?  
{ G:`Jrh  
breakWhile = false; VU9P\|c@<  
break; Cw $^w  
} \F~Cbj+'Nu  
} G4' U;  
if(breakWhile) Cg pT(E\E  
break; m7vxzC*  
'hO;sL  
`aL|qyrq#  
//count++; w9$8t9$|  
//if(count>4) /T)n5X  
// siteStop(); acQNpT  
} ; ,jLtl  
~qxXou,J  
Y&+_p$13  
System.err.println("文件下载结束！"); e oSM@Isu  
} |SKG4_wGe  
catch(Exception e){e.printStackTrace ();} z\>X[yNpA  
} J"/z?!)IB  
PMs_K"-K  
#J724`  
//获得文件长度 ^G
&D4uZ  
public long getFileSize() ?K {1S  
{ JZ/O0PW  
int nFileLength = -1;  ii  y3  
try{ 
W'h0Zg  
URL url = new URL(siteInfoBean.getSSiteURL()); S.|kg2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AYIz;BmWy  
httpConnection.setRequestProperty("User-Agent","NetFox"); <[:7#Yo g  
2pa3}6P+  
PlH`(n#  
int responseCode=httpConnection.getResponseCode(); $'YKB8C  
if(responseCode>=400) ggc?J<Dv  
{ w/5^R  
processErrorCode(responseCode); V9u\;5oL  
return -2; //-2 represent access is error ~49N  
} 8`2<g0V2  
(0#F]""\e  
=4<S8Cp  
String sHeader; X|E+K  
rw[{@|)'z  
aroVyUs3j  
for(int i=1;;i++) 9<h]OXv  
{ ds;cfj[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nVn|$ "r  
//Utility.log(in.readLine()); ywynx<Wg  
sHeader=httpConnection.getHeaderFieldKey(i); Kt,ynA  
if(sHeader!=null) !L. K)9I  
{ dP7Vsa+  
if(sHeader.equals("Content-Length")) ?4[Oh/]R  
{ SiqX1P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }BdVD t  
break; a,*p_:~i  
} %m{.l4/!O  
} 1"&;1Ts  
else 6$s0-{^  
break; H9VXsFTW  
} |\|)j>[i  
} b>=Wq  
catch(IOException e){e.printStackTrace ();} >q@Sd  
catch(Exception e){e.printStackTrace ();} MiH}VfI
  
AXP`,H  
7X{bB  
Utility.log(nFileLength);
bLEATT[  
BCUt`;q ]B  
BBR"HMa
4  
return nFileLength; &49$hF g6"  
} fA_%8CjI  
=Y/fF  
pq[X)]z|  
//保存下载信息（文件指针位置） W.`Xm(y  
private void write_nPos() Z%5nVsm:G  
{ g:DTVq  
try{ yvd `nV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T3 9C lH  
output.writeInt(nStartPos.length); y(nsyA  
for(int i=0;i<nStartPos.length;i++) VP%i1|XZJ  
{ %7v@n+Q  
// output.writeLong(nPos); kg: uGP9  
output.writeLong(fileSplitterFetch.nStartPos); Fu4EEi  
output.writeLong(fileSplitterFetch.nEndPos); f-3'D-{EKt  
} Cb{A:\>Q{  
output.close(); $HBT%g@UN  
} juMxl  
catch(IOException e){e.printStackTrace ();} tpa^k  
catch(Exception e){e.printStackTrace ();} (#bp`Kih  
} xd|~+4  
!
ASoXQRz  
g+}s:9  
//读取保存的下载信息（文件指针位置） K6v $#{$6  
private void read_nPos() aM{@1mBm  
{ 8pk#sJ51  
try{ f(6UL31  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); P}hY{y'  
int nCount = input.readInt(); 4W!\4Va  
nStartPos = new long[nCount]; j&dx[4|m:h  
nEndPos = new long[nCount]; vS$oT]-hKE  
for(int i=0;i<nStartPos.length;i++) &{zwM |Q@?  
{ dY/u<4  
nStartPos = input.readLong(); +[whh  
nEndPos = input.readLong(); 4e+BqCriC*  
} *5y W  
input.close(); g=xv+e  
} au~]  
catch(IOException e){e.printStackTrace ();} -VWCD,c  
catch(Exception e){e.printStackTrace ();} =_8 UZk.  
} _,_8X7   
X a"XB  
VFl 1 f  
private void processErrorCode(int nErrorCode) F?b'L JS  
{ "7kgez#Y  
System.err.println("Error Code : " + nErrorCode); mQJ4;BJw  
} =t3vbV  
N.0HfYf  
Ht|",1yr+  
//停止文件下载 $N;"}Gz  
public void siteStop() j|[(*i%7|  
{ HDF"]l;  
bStop = true; 3}B5hht"D  
for(int i=0;i<nStartPos.length;i++) ADYx.8M|9i  
fileSplitterFetch.splitterStop(); 8cK\
myn.  
/M^V2=  
'Aj(i/CM  
} s(AJkO'`  
} 
AanH{  
//负责部分文件的抓取 ]{!!7Zz  
**FileSplitterFetch.java K85_>C%g  
*/ H(15vlOD  
package NetFox; Dac ^*k=D  
1C_'H.q<=  
:[Qp2Gg O\  
import java.io.*; R}DX(T,K  
import java.net.*; L1hD}J'$4  
'e.q 7Jpd  
w"cM<Ewu  
public class FileSplitterFetch extends Thread { 4%wq:y< )/  
$D QD$  
.pZo(*  
String sURL; //File URL K2cq97k
,d  
long nStartPos; //File Snippet Start Position 8jy-z"jc  
long nEndPos; //File Snippet End Position e0f":Vct  
int nThreadID; //Thread's ID >ik1]!j]Lv  
boolean bDownOver = false; //Downing is over ]3L@$`ys  
boolean bStop = false; //Stop identical J3;Tm~KJ_  
FileAccessI fileAccessI = null; //File Access interface h/I@_?k+  
3`58ah  
;>9OgO  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^^G-kg  
{ ?"{QK:`  
this.sURL = sURL; PZys u  
this.nStartPos = nStart; gyi)T?uS)  
this.nEndPos = nEnd; @Q;i.u{V  
nThreadID = id; P*pbwV#|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r\(v+cd  
} 9i0M/vx  
=o
p`fn%  
tC&fAE:S  
public void run() u3]Uxy  
{ [{`)j  
while(nStartPos < nEndPos && !bStop) p?Ed- S  
{ \n#]%X5c  
Hqvc7-c6  
QU:EY'2  
try{ pT4qPta,2  
URL url = new URL(sURL); NEA_Plt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 79D=d'eA  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3brb*gI_b  
String sProperty = "bytes="+nStartPos+"-";  bH*@,EE  
httpConnection.setRequestProperty("RANGE",sProperty); )ZHc$+fU  
Utility.log(sProperty); 16I&7=S,  
%=V"CJ$|  
{3hqp*xl  
InputStream input = httpConnection.getInputStream(); 8N%z9b  
//logResponseHead(httpConnection); 7p^@;@V  
~<n(y-P^  
>;)2NrJV  
byte[] b = new byte[1024]; "2a$1Wmj(  
int nRead; 0Cl,8P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <B!'3C(P  
{ ##H;Yb  
nStartPos += fileAccessI.write(b,0,nRead); Y}ng_c  
//if(nThreadID == 1) R|iEv
t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -yoAxPDW  
} [|4}~UV  
q]px(  
a mqOxb  
Utility.log("Thread " + nThreadID + " is over!"); M;*$gV<x  
bDownOver = true; \yNQQ$B  
//nPos = fileAccessI.write (b,0,nRead); u?F (1iN=  
} 20aZI2sk`  
catch(Exception e){e.printStackTrace ();} XYjcJ  
} XYe~G@Q Z  
} B/mYoK  
GM](=|
F  
wUoiXi09  
//打印回应的头信息 U;g S[8,p  
public void logResponseHead(HttpURLConnection con) 0#QKVZq2>  
{ il12T`a  
for(int i=1;;i++) U/Wrh($ #4  
{ }f#_4ACaD  
String header=con.getHeaderFieldKey(i); (?\?it-  
if(header!=null) thuRNYv<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gE\b982  
Utility.log(header+" : "+con.getHeaderField(header)); j$Nf%V 6Y  
else (S|a 9#  
break; (YwalfG {C  
} R2rsJ  
} %ISq>A)%  
}B0sC%cm  
rfs(#  
public void splitterStop()  GP+2/D  
{ TnNWO+kg  
bStop = true; HY;9?KJ'  
} o)&"Rf  
GRT]aw  
3pSj kS|?>  
} */w7?QOv  
ydQ!4  
wiJRCH  
/* 56DoO'  
**FileAccess.java l$a?A[M$  
*//文件访问(定位，写) ! Z;T-3^.  
package NetFox; U\jb"  
import java.io.*; #op:/j  
@QdnjX
II*  
N}b^fTq  
public class FileAccessI implements Serializable{ jvHFFSK  
]78!!G[`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pY
o=oI  
RandomAccessFile oSavedFile; KVR~jF%  
long nPos; <sX VW  
JJ?I>S N!  
?^u^im  
public FileAccessI() throws IOException 2.-o@im0  
{ ?mx\eX{  
this("",0); -\#lF?fzb  
} &gn-Wb?  
"uKFOV?j&  
B+] D5K  
public FileAccessI(String sName,long nPos) throws IOException |sIr?RL{C  
{ c~imE%  
oSavedFile = new RandomAccessFile(sName,"rw"); ,%[4j9#!_  
this.nPos = nPos; "R[l ZJ@  
oSavedFile.seek(nPos); E]I$}>k  
} "AC^ rz~U  
2&he($HIzg  
KjYAdia:H  
public synchronized int write(byte[] b,int nStart,int nLen) ;3"@g]e  
{ VUtXxvH  
int n = -1; 5u$D/* Eb  
try{ n2f6p<8A  
oSavedFile.write(b,nStart,nLen); y$b]7O  
n = nLen; `Ye8 Q5v"]  
} 'T,c.Vj)  
catch(IOException e) h
|bT)!|  
{ w0w1PE-V=  
e.printStackTrace (); h3!$r~T!a:  
} PFrfd_s{>\  
]$A(9Pn"  
~#PLAP3-  
return n; kn"q:a
D  
} "Sridh?  
T2FE+A]n9  
v2)g 1sXd  
} O
o8qyW  
+=BAslk  
S6xgiem  
/* 7 oQ[FdRn*  
**SiteInfoBean.java mi,&0xDea  
*/ 9\JQ7$B  
package NetFox; SA;#aj}rV  
Y?K{(szo ?  
d2N:^vvvR  
public class SiteInfoBean { }TB(7bbd;  
n
,$z>  
!H@0MQ7  
private String sSiteURL; //Site's URL M.q=p[  
private String sFilePath; //Saved File's Path a5jL7a?6]  
private String sFileName; //Saved File's Name J00
VTb`  
private int nSplitter; //Count of Splited Downloading File o!c] (  
 ?K_ '@  
pH@]Y+W  
public SiteInfoBean() SaOYu &>  
{//nSplitter的缺省值为5 \%0n}.A  
//default value of nSplitter is 5 r'GP$0rr9!  
this("","","",5); U{@5*4  
} T/1gI9X  
rl08R  
pkgjTXR2b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lIRlMLuG  
{ |7k_N|E  
sSiteURL= sURL; Jh&~ToF!  
sFilePath = sPath; qS|\JG  
sFileName = sName; T>`74B:  
this.nSplitter = nSpiltter; QHq,/kWY  
72W s K"  
O%8EZyu  
} tDg}Ys=4K>  
)2IH 5  
[ic87
0_  
public String getSSiteURL() _)T5lEFl=  
{ ml`8HXK0  
return sSiteURL; #OO>rm$  
} <h-vjz  
V[o`\|<  
c0&Rg#  
public void setSSiteURL(String value) ?a(L.3E  
{ s$D ^>0  
sSiteURL = value; 7*5Z  
} [* ?Awf`  
Z;/$niY  
"pP^*9FrA  
public String getSFilePath() ~`M\Ir  
{ 0'YG6(h  
return sFilePath; kE9esC3  
} !K f#@0E..  
aFz5leD  
5,-U.B}  
public void setSFilePath(String value) },+wJ1  
{ ,'xYlH3s  
sFilePath = value; *37uy_EpV  
} %h?x!,q Y  
!$-\;<bZw  
YG[;"QR  
public String getSFileName() #9-P%%kQ  
{ (0YZZ93  
return sFileName; SN7"7joP<  
} SCvVt  
N,8/Y  
=U%Rvm  
public void setSFileName(String value) -K9c@?  
{ p$Ox'A4  
sFileName = value; aT>'.*\]  
} mGp.3{j  
if|+EN%  
<Ln1pV~k  
public int getNSplitter() S}p4iE"n  
{ s<qe,'Y  
return nSplitter; +gtrt^:]l  
} <:SZAAoIV  
)OiT{-m  
b2b^1{@h;v  
public void setNSplitter(int nCount) e/0
<[s*#Q  
{ M`rl!Ci#  
nSplitter = nCount; 91=OF*w  
} TT=b79k  
} ]E\n9X-{  
;;L[e]Z  
1 $/%m_t  
/* }:X*7 n(&  
**Utility.java Vn*tpbz  
*/ Ut2y;2)a  
package NetFox; H,Z;=N_  
rE}%KsZ  
1pArZzm>  
public class Utility { ZovW0Q)m  
4"gM<z  
)+:EJH~  
public Utility() N[<\>Ps|u  
{ 6d_'4B  
yzqVz_Fi*W  
b0lq\9  
} $2W%2rZ  
(p2
K36,9m  
//线程睡眠 UK<Nj<-'t
 
public static void sleep(int nSecond) zIh['^3.n  
{ T6 '`l?H`;  
try{ ;W>k@L  
Thread.sleep(nSecond); l c+g&f  
} 9FB19  
catch(Exception e) -r-k_6QP  
{ ^J$2?!~  
e.printStackTrace (); R8ZK]5{o  
} spt6]"Ni  
} KXx32 b,~  
e" St_z(  
//日志 j'A_'g'^  
public static void log(String sMsg) Y;?{|  
{ _lamn}(x0  
System.err.println(sMsg); V5UF3'3;}  
} ["h5!vj  
9I&xfvD,  
nih0
t^m'  
public static void log(int sMsg) 19w*!FGX  
{ 7Zlw^'q$:L  
System.err.println(sMsg); wK?vPS  
} Tj:B!>>  
} |S_eDjF  
-[cTx[Z,  
HMSO=)@+  
/* Qk:
Y2mL  
**TestMethod.java 8fl`r~bqZ  
*/ wne,e's}   
package NetFox; LDPUD'  
Xu%'Z".>:  
uG,5BV.M  
public class TestMethod { >m$1Xx4#GV  
jPUwSIP  
|5lk9<z  
public TestMethod() be.*#[  
{ ///xx/weblogic60b2_win.exe E=nIRG|g  
try{ vSEuk}pk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y*qVc E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #d6)#:uss  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {\8
1i8b]  
fileFetch.start(); o]4*|ARPs  
} ? m DI#~)  
catch(Exception e){e.printStackTrace ();} E|iQc8gr&  
F(>Np2oi6  
.+$Q<L  
} <3LbNFP  
9Z4nAc
 
RoPRQCE  
public static void main(String[] args) ]s<[D$ <,  
{ t'n pG}`tE  
new TestMethod(); 2LF/H$]o5  
} \NPmym_6J  
} .P8&5i)'P,  
点击下载更多相关资料