http断点续传简单实现（java)

/* /8\&f%E  
**SiteFileFetch.java 0K0=Ob^(e  
*/ l0if#?4\r  
package NetFox; r$Y!Y#hwQ  
import java.io.*; Ky$G$H  
import java.net.*; 7,UFIHq  
@!3^/D3  
`|Z@UPHzG  
public class SiteFileFetch extends Thread { '/g+;^_cB  
S=SncMO nE  
Cpv%s 1M  
SiteInfoBean siteInfoBean = null; //文件信息Bean $4JX#lkt  
long[] nStartPos; //开始位置 }tO<_f))  
long[] nEndPos; //结束位置 PM!t"[@&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yuDd% 1k  
long nFileLength; //文件长度 q.Z#7~6`3  
boolean bFirst = true; //是否第一次取文件 u#k,G`  
boolean bStop = false; //停止标志 AiK
4t-  
File tmpFile; //文件下载的临时信息 BrMp_M  
DataOutputStream output; //输出到文件的输出流 #-j! ;?  
B-'BJ|*4I  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _4B iF?1  
public SiteFileFetch(SiteInfoBean bean) throws IOException n@[</E(  
{ .BDRD~kB  
siteInfoBean = bean; _kX/LR"L+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %uqD\`-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eAKQR  
if(tmpFile.exists ()) !&p:=}s  
{ sNmC#,  
bFirst = false; 4Xk;Qd  
read_nPos(); 00a<(sS;  
} 0P3|1=  
else 4Olv8nOe<  
{ PFgjW
p"Y  
nStartPos = new long[bean.getNSplitter()]; ]{+M>i[  
nEndPos = new long[bean.getNSplitter()]; b(-t)5^}  
} } %CbZ/7&  
qS}RFM5|  
~V"cLTj"  
)wzs~Fn/  
} <&EO=A  
A6y~_dt  
JX$NEq(  
public void run() ?WtG|w  
{ -L3 |9k  
//获得文件长度 JKi@Kw  
//分割文件 7cP
[o+  
//实例FileSplitterFetch >c\v&k>6.  
//启动FileSplitterFetch线程 \{=`F`oB=  
//等待子线程返回 akc"}+-oX  
try{ h*%0@  
if(bFirst) n5*{hi  
{ 4OZ5hH h  
nFileLength = getFileSize(); y_4krY|Zx  
if(nFileLength == -1) |
od4kt  
{ SAE'?_  
System.err.println("File Length is not known!"); B6'%J  
} a.&#dxgW[  
else if(nFileLength == -2) 6|>\&Y!Q  
{ KkL:p?@n  
System.err.println("File is not access!"); r|\'9"@  
} EfBVu  
else 0.BUfuuh  
{ uJ/?+5TU  
for(int i=0;i<nStartPos.length;i++) <X I35\^  
{ c<h!Q
nJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #u<oEDQ  
} ZYA.1VrM  
for(int i=0;i<nEndPos.length-1;i++) l@Eq|y,  
{ W]yClx \  
nEndPos = nStartPos[i+1]; KIAe36.~  
} '=Kof1  
nEndPos[nEndPos.length-1] = nFileLength; Vk
TlPmr  
} VM]GYz|#]  
} u_6B
HsU  
ULNAH`{D  
Y7:Y{7E7  
//启动子线程 4`UL1)A]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |:e|~sism  
for(int i=0;i<nStartPos.length;i++) eb.cq"C  
{ %7(kP}y*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xf^<ec  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >Z2,^5P{  
nStartPos,nEndPos,i); ,na=~.0R:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e\A(#l@g  
fileSplitterFetch.start(); 2%{YYT   
} GIRSoRVsh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /J[H5uA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =,AC%S_D~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F[7Kw"~J  
nEndPos = " + nFileLength); d@D;'2}Yc  
// fileSplitterFetch[nPos.length-1].start(); X@yr$3vC  
;X$q#qzN
#  
o/dMm:TF  
//等待子线程结束 pVV}1RDa  
//int count = 0; vhYMWfbY  
//是否结束while循环 `dgM|.w5=  
boolean breakWhile = false; 4j=<p@  
V{T{0b"\U  
h"PS-]:CD  
while(!bStop) ` Y{>2UFX  
{ { p!_-sL  
write_nPos(); "^9[OgE:  
Utility.sleep(500); O/DAf|X|  
breakWhile = true; mZbWRqP[|_  
7ZV~op2Q  
yNrinYw  
for(int i=0;i<nStartPos.length;i++) T}n}.JwU  
{ J+}+"h~.  
if(!fileSplitterFetch.bDownOver) jNe(w<',P  
{ wUK7um  
breakWhile = false; eC>"my`  
break; H:q)^$s  
} pwFU2}I  
} FpdDIa  
if(breakWhile) ]3O 4\o  
break; Wa[x`:cT?u  
e~+(7_2  
f=:3!k,S  
//count++; E7X!cm/2<  
//if(count>4) m/YH^N0  
// siteStop(); >:F,-cx<  
} :H!(?(Pie  
k'[ S@+5  
6%g
B E  
System.err.println("文件下载结束！"); }A4nJ>`tq  
} hncS_ZA  
catch(Exception e){e.printStackTrace ();} Pv
/Pww\  
} )|w*/JK\Z  
4AY _#f5u  
N+CXOI=6x  
//获得文件长度 NI5]Nz<?  
public long getFileSize() >H0) ph  
{ ^w:OS5%R  
int nFileLength = -1; 0W T#6D  
try{
5:Yck<  
URL url = new URL(siteInfoBean.getSSiteURL()); ~9JW#HHzn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F . K2  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5l41Q  
~lzdbX  
lQV|U;~D  
int responseCode=httpConnection.getResponseCode(); ]ZzoJ7lr  
if(responseCode>=400) uQGz;F x  
{ 7$!`p,@we/  
processErrorCode(responseCode); AIZW@Nq.5  
return -2; //-2 represent access is error "wA0 LH_  
} V I6\   
M"=8O>NZ2  
$hG;2v  
String sHeader; EKZ$Q4YE  
s<A*[  
8
G0  
for(int i=1;;i++) DE*MdfP0  
{ *0%4l_i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uy/y wm/?=  
//Utility.log(in.readLine()); .A3DFm3t  
sHeader=httpConnection.getHeaderFieldKey(i); -"W)|oC_  
if(sHeader!=null) :8p&#
M  
{ BRQ"A,  
if(sHeader.equals("Content-Length")) aB6Ye/Io  
{ &EAk z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [096CK  
break; <Ctyht0c.  
} ,f}h}  
} H4M{_2DO  
else `1n
RcY  
break; 9<xTu>7J  
} BG'6;64kx6  
} a @6^8B?w;  
catch(IOException e){e.printStackTrace ();} G/v|!}?wG  
catch(Exception e){e.printStackTrace ();} `kv1@aQPL  
eYJ{LPo  
m)s xotgXf  
Utility.log(nFileLength); <"*"1(wN  
ZhH+D`9  
hVMYB_<~  
return nFileLength;  X?tj$  
} Q]< (bD.7  
+"'F B
e  
y^2#9\}K  
//保存下载信息（文件指针位置） tf4*R_6;1$  
private void write_nPos() ecn}
iN  
{ LO"_NeuL  
try{ 2 9q?$V(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +0VG[c\8  
output.writeInt(nStartPos.length); A#<vG1  
for(int i=0;i<nStartPos.length;i++)
$bk>kbl P  
{ aK]7vp+  
// output.writeLong(nPos); E@:Q 'g%  
output.writeLong(fileSplitterFetch.nStartPos); KwS`3 6:  
output.writeLong(fileSplitterFetch.nEndPos); zQ,f5x  
} 2=>*O  
output.close(); Z.!g9fi8>  
} egfi;8]E  
catch(IOException e){e.printStackTrace ();} brb[})}  
catch(Exception e){e.printStackTrace ();} ya:sW5fk  
} f%c06Un=  
^w>&?A'!  
SU/G)&Mi  
//读取保存的下载信息（文件指针位置） Q~phGD3!~  
private void read_nPos() ]bIt@GB  
{ brntE:  
try{ DlDB=N0@S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SaCx)8ul0  
int nCount = input.readInt(); 'f 3HKn<L  
nStartPos = new long[nCount]; +4Q[N;[+*  
nEndPos = new long[nCount]; XTV0Le\
f  
for(int i=0;i<nStartPos.length;i++) &`\ep9  
{ ;Tta
H  
nStartPos = input.readLong(); XJUEwX  
nEndPos = input.readLong(); b7bSTFZxC  
} _ j~4+H  
input.close(); oew|23Ytb  
} A^-iHm  
catch(IOException e){e.printStackTrace ();} W+8^P( K  
catch(Exception e){e.printStackTrace ();} 8/Mx5~ R  
} ~P/]:=  
R;r|cep  
*|oPxQCtK  
private void processErrorCode(int nErrorCode) F=srkw:*.  
{ 3!aEClRtq  
System.err.println("Error Code : " + nErrorCode); ?9p$XG  
} =c&
62;O  
3)Zu[c[%'J  
Vb2\/e:k  
//停止文件下载 ZW>o5x__b  
public void siteStop() )!A 2
>  
{ NEMEY7De2  
bStop = true; Rs2-94$!5  
for(int i=0;i<nStartPos.length;i++) M+0x;53nz  
fileSplitterFetch.splitterStop();
/jR8|sb  
Wm(:P  
2 l(Dee Y  
} X
tkw Z3  
} gwiR/(1  
//负责部分文件的抓取 Tv\HAK<N  
**FileSplitterFetch.java (k
8Z=/N~  
*/ /_q#ah  
package NetFox; M|k&TTV  
.3
@Ng  
hfg O  
import java.io.*; (etUEb^}T  
import java.net.*; 45)D+  
};rm3;~ eg  
9\AS@SH{^T  
public class FileSplitterFetch extends Thread { wlrIgn%  
VG)="g[%)  
uJY.5w  
String sURL; //File URL \n_3Bwd~  
long nStartPos; //File Snippet Start Position #&V5H{  
long nEndPos; //File Snippet End Position 80}4/8  
int nThreadID; //Thread's ID kbhX?; <`  
boolean bDownOver = false; //Downing is over &Pq\cNYzW  
boolean bStop = false; //Stop identical HyEa_9  
FileAccessI fileAccessI = null; //File Access interface "R23Pi  
LJWTSf"f?  
_dr*`yXi  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u
f]Y^,2  
{ E5gl^Q?Z  
this.sURL = sURL; 7/?DPwbx  
this.nStartPos = nStart; Y%g "Y  
this.nEndPos = nEnd; V9T 4+  
nThreadID = id; N<liS3>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $@2"{9Z  
} y@A6$[%(E|  
^X&)'H  
&dRjqn^&X  
public void run() ra
:GzkIw  
{ :CTL)ad2  
while(nStartPos < nEndPos && !bStop) MtUY?O.P2  
{ n+?-�  
c|lU(Tf  
#W|!fILL  
try{ IBET'!j4"  
URL url = new URL(sURL); ufPCx|x~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >)^NJ2Fd  
httpConnection.setRequestProperty("User-Agent","NetFox"); <Y>3  
String sProperty = "bytes="+nStartPos+"-"; ,eXFN?CB  
httpConnection.setRequestProperty("RANGE",sProperty); (@q3^)I4  
Utility.log(sProperty); )[jy[[K(  
g/#~N~&  
+9zA^0  
InputStream input = httpConnection.getInputStream(); ~KRnr0  
//logResponseHead(httpConnection); q5p e~  
,dcg?48  
)b92yP{  
byte[] b = new byte[1024]; EeB3 }  
int nRead; t#5:\U5r.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TEWAZVE*  
{ Pbe7SRdr^  
nStartPos += fileAccessI.write(b,0,nRead); <tuS,.  
//if(nThreadID == 1) Dx3%KS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _2OuskL  
} t77'fm  
Ea]T>4  
v459},!P  
Utility.log("Thread " + nThreadID + " is over!"); Q]#Z9H  
bDownOver = true; 76u{!\Jo/{  
//nPos = fileAccessI.write (b,0,nRead); ^f|<R8`  
} -~O/NX  
catch(Exception e){e.printStackTrace ();} V#J"c8n  
} RZh}:  
} X+iK<F$  
!M(:U,?B  
0`n 5x0R  
//打印回应的头信息 8=F%+  
public void logResponseHead(HttpURLConnection con) jDTUXwx7V  
{ SF< [FM%1  
for(int i=1;;i++) "PzP;Br  
{ DA=1KaJ.  
String header=con.getHeaderFieldKey(i); B< hEx@  
if(header!=null) gxmc|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); oZ:{@=  
Utility.log(header+" : "+con.getHeaderField(header)); =}R~0|^  
else W:O0}  
break; \_VmY!I5\  
} .z
SD`v@[  
} nxQ}&n  
s$GF 95^  
ET-Vm >]  
public void splitterStop() _-%d9@x  
{ jczq`yW  
bStop = true; sRq U]i8l  
} Pp*}R2  
~@P)tl>  
j=ihbR^]Tl  
} YPszk5hn  
ezZph"&  
Ttv'k*$cP  
/* O]qPmEj  
**FileAccess.java v!trsjb  
*//文件访问(定位，写) `?uPn~,e8  
package NetFox; +< KNY  
import java.io.*; "}zda*z8  
z-@-O  
J+Bdz6lt  
public class FileAccessI implements Serializable{ t5)J;0/  
TyOH`5D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #DUh(:E'`  
RandomAccessFile oSavedFile; _tj&Psp  
long nPos; nwf7M#3d  
4#:\?HAu!  
~NNv>5t5  
public FileAccessI() throws IOException  %+wF"  
{ }-p,iTm  
this("",0); zu<3^=3  
} @^?XaU  
YwAnqAg  
|Q!4GeQL[  
public FileAccessI(String sName,long nPos) throws IOException p)/ p!d[T/  
{ 'qy#)F  
oSavedFile = new RandomAccessFile(sName,"rw"); 7lU.Nit  
this.nPos = nPos; ow.j+<M  
oSavedFile.seek(nPos); 2U9&l1P=  
} #C\4/g?=,  
<*
Y'lV  
\ e,?rH  
public synchronized int write(byte[] b,int nStart,int nLen) 5@P-g  
{ ]0/p 7N14  
int n = -1; ]MAT2$"le  
try{ IKcKRw/O$  
oSavedFile.write(b,nStart,nLen); ;fGx;D  
n = nLen; U)[ty@zyF  
} Ror2qDF  
catch(IOException e) LC-)'Z9}5  
{ (vQ+e
 
e.printStackTrace (); <v$QM;Ff  
} J&6:d  
Gzm$OHbn  
o~C('1Fdb  
return n; U CY2]E  
} iP "EA8  
=nVmthGw  
6vp0*ww  
} H?U't 09  
<y>:B}9'  
)i!^]|$  
/* PayV,8   
**SiteInfoBean.java Fe$/t(  
*/ %j{.0H  
package NetFox; s#^pC*,'  
%^.P~s6  
@J vZ[T/  
public class SiteInfoBean { ~L4eZ  
D;js.ZF  
Y\?j0X;  
private String sSiteURL; //Site's URL arh@`'Q  
private String sFilePath; //Saved File's Path |F!F{d^p  
private String sFileName; //Saved File's Name E _iO@  
private int nSplitter; //Count of Splited Downloading File mU
G %LM  
8QF`,o
XQO  
7GZq|M_:y  
public SiteInfoBean() Z2p> n`D  
{//nSplitter的缺省值为5 +t]Xj1Q  
//default value of nSplitter is 5 yP\Up  
this("","","",5); ("Dv>&w9  
} ZBc|438[  
z[&s5"  
]k+m=OR{/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _;e\:7<m  
{ Q$=*aUU%G  
sSiteURL= sURL; }<[Db}?9  
sFilePath = sPath; +LzovC@^  
sFileName = sName; `6Hf&u<  
this.nSplitter = nSpiltter; XDLEVSly7  
c> G@+  
-G b-^G  
} ?~F. /  
9L)L|4A.l  
fp&Got!pB  
public String getSSiteURL() h~miP7,c<u  
{ $TG?4  
return sSiteURL; .JAcPyK^  
} &" h]y?Q  

"mZ.V  
?R6`qe_
F  
public void setSSiteURL(String value) 9 5 H?{  
{ ,Y!zORv<7  
sSiteURL = value; @ajM^L!O  
} 9]$`)wZ  
Y}.Ystem  
PXEKV0y  
public String getSFilePath() V5MO}  
{ 6Rz[?-mkLO  
return sFilePath; GGE[{Gb9  
} c8ZCs?   
8H $#+^lW  
DO^y;y>  
public void setSFilePath(String value) >q(6,Mmb  
{ xm^95}80yh  
sFilePath = value; :ba/W&-d  
} eXzXd*$S  
'_o@VO  
@"8R3BN  
public String getSFileName() ;<-7*}Dj  
{ rn" pKUd  
return sFileName; \P?A7vuhLs  
} K]"Kf{bx  
Tf-CEHWD  
uec|S\~M  
public void setSFileName(String value) -p8e  
{ ~A >oO-0K  
sFileName = value; )H+kB<n  
} PDC]wZd/  
-g~~]K%  
%f!iHo+Z  
public int getNSplitter() 7~vqf3ON4J  
{ ]!Zty[  
return nSplitter; GqUSVQ  
} )%mAZk-*;^  
3{3/: 7  
=_QkH!vI  
public void setNSplitter(int nCount) i6>R qP!69  
{ pP\h6b+B  
nSplitter = nCount; knSuzq%
*  
} n,nisS  
} }O*WV1  
V/bH^@,sA  
aZgNPw  
/* )w"0w(  
**Utility.java 0Q1/n2V  
*/ (=JueF@J  
package NetFox; ( u f5\}x  
j=j+Nf$  
9#@Zz4Ww  
public class Utility { IVteF*8hU  
,F:=(21  
295w.X(J
 
public Utility() rJ(OAKnY  
{ 7a<_BJXx  
E1W:hGI  
(6k>FSpg  
} t!jwY/T  
O5;-Om  
//线程睡眠 Yu3_=: <C  
public static void sleep(int nSecond) i<iXHBs  
{ <SQ(~xYi
  
try{ 263*: Y  
Thread.sleep(nSecond); btQet.  
} N!m%~kS9k<  
catch(Exception e) T %/  
{ r}EM4\r  
e.printStackTrace (); ,so4Lb(vG  
} !}q."%%J_%  
} rzV"Dm$'  
Z#7U "G-A  
//日志 F^rl$#pCS  
public static void log(String sMsg) AgsR-"uh  
{ Zh,]J `  
System.err.println(sMsg); kfCKhx   
} EUZq$@uWL  
bp%S62Dj  
J @B4 R&V  
public static void log(int sMsg) |<Bpv{]P  
{ -S$$/sR  
System.err.println(sMsg); ,}<RrUfD  
} 76cEKH
a<  
} -+P7:4/  
/f&By p  
b *9-}g:  
/* `a'`$'j  
**TestMethod.java k1iLnza%  
*/ ('d{t:TsY  
package NetFox; b42QBTeg  
~4^p}{  
@1.9PR$x  
public class TestMethod { ]fC7%"nB  
][t6VA  
$8@+j[>  
public TestMethod() W5I=X]&  
{ ///xx/weblogic60b2_win.exe \`gE
u{  
try{ iGa}3pF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s3< F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .. UoyBV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <[9?Rj@  
fileFetch.start(); (nz}J)T&  
} :c<*%*e  
catch(Exception e){e.printStackTrace ();} SG`)PW?  
#eLN1q&Z  
)* 3bkKVB  
} ,s? dAy5  
Ff)@L-Y\K  
P;c0L;/  
public static void main(String[] args) 8[HZ@@  
{ NL-_#N$  
new TestMethod(); R&!]Rl9hf  
} +-P<CCvWz  
} 4W-"|Z_x  
点击下载更多相关资料