http断点续传简单实现（java)

/* QM~~b=P,\  
**SiteFileFetch.java ExFz@6@  
*/ 4T~wnTH0Xg  
package NetFox; SoFl]^l  
import java.io.*; [CAFh:o  
import java.net.*; xNRMI!yv   
`O%
O[  
3".#nN  
public class SiteFileFetch extends Thread { .rX,*|1x  
,sg\K>H=  
[4yw? U  
SiteInfoBean siteInfoBean = null; //文件信息Bean P*ZMbAf.  
long[] nStartPos; //开始位置 =L?2[a$2;  
long[] nEndPos; //结束位置 ^oE#;aS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u2[L^]|  
long nFileLength; //文件长度 d+ [2Sm(7  
boolean bFirst = true; //是否第一次取文件 ZC^NhgX  
boolean bStop = false; //停止标志 PH^Gj
m  
File tmpFile; //文件下载的临时信息 (bB"6 #TI  
DataOutputStream output; //输出到文件的输出流 e)XnS'  
iG=Di)O  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }{&;\^i  
public SiteFileFetch(SiteInfoBean bean) throws IOException CHCT e  
{ [;~"ctf{  
siteInfoBean = bean; nuA 0%K  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F]0 qt$GO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o?IrDQ2gmh  
if(tmpFile.exists ()) Czy}~;_Ay  
{ yGV>22vv M  
bFirst = false; ]9W7]$  
read_nPos(); 5e?<x>e  
} tCwB7c-  
else 7y.iXe!P  
{ ao
|n<*}  
nStartPos = new long[bean.getNSplitter()]; e3[Q6d&|  
nEndPos = new long[bean.getNSplitter()]; {/,AMJ<:G]  
} _~F 0i?  

O{U j  
`'pAiu  
a#9pN?~  
} p|BoEITL  
#]gmM  
AYp~;@  
public void run() q_9 tbZ;  
{ Wu$yB!  
//获得文件长度 DhsvN&yNM  
//分割文件 )ac!@slb^7  
//实例FileSplitterFetch +NiCt S  
//启动FileSplitterFetch线程
/fAAQ7  
//等待子线程返回 K(WKx7Kky^  
try{ vF[ 4kDHk  
if(bFirst) hp2$[p6O  
{ h b8L[ 4  
nFileLength = getFileSize(); y3PrLBTz  
if(nFileLength == -1) {9^p3Q+:P  
{ ,^DP  
System.err.println("File Length is not known!"); B^ddi  
} A<(DYd1H  
else if(nFileLength == -2) Ea-U+7JC  
{ Qam48XZ >  
System.err.println("File is not access!"); H4sc7-  
} +!$`0v
  
else }WBHuVcZG  
{ q1ZZ T"'  
for(int i=0;i<nStartPos.length;i++) ojA!!Ru  
{ Ap4.c8f?Q-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $~
%h4  
} 4x#tUzb;  
for(int i=0;i<nEndPos.length-1;i++) lXzm)  
{ 33&\E- Q>  
nEndPos = nStartPos[i+1]; _c5*9')-)  
} 4:/^.:  
nEndPos[nEndPos.length-1] = nFileLength; - leYR`P  
} ]e+&Pxw]e  
} XGjFb4Tw
7  
{OOn
7=  
$ \o)-3  
//启动子线程 -8<vWe  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h ^s8LE3  
for(int i=0;i<nStartPos.length;i++) JO90TP $  
{ I`i"*z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t*u#4I1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }Gy M<!:  
nStartPos,nEndPos,i); XP?)xDr8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vJV/3-yX  
fileSplitterFetch.start(); #3'M>SaoH  
} vbZ!NO!H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S2nX{=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c& bms)Jwa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5}Xi`'g,  
nEndPos = " + nFileLength); NSH4 @x  
// fileSplitterFetch[nPos.length-1].start(); ~-B+7  
1MT,A_L  
f*9O39&|  
//等待子线程结束 7q5*grm  
//int count = 0; =2ED w_5E  
//是否结束while循环 g2=PZR$  
boolean breakWhile = false; y~VI,82*  
$em'H,*b3  
)S/=5Uc  
while(!bStop) z0#2?o  
{ ,CuWQ'H  
write_nPos(); qPN9Put  
Utility.sleep(500); )feZ&G]  
breakWhile = true; n=AcN  
Kpa$1x  
D!.1R!(Z  
for(int i=0;i<nStartPos.length;i++) w*;"@2y;eY  
{ `u PLyS.  
if(!fileSplitterFetch.bDownOver) 6]kBG?m0  
{ Kr `/sWZ  
breakWhile = false; ecR)8^1 '  
break; ]^>:)q  
} 6 .)Xeb"  
} 3
eX
Io=  
if(breakWhile) vLyazVj..  
break; B&0W P5OF  
CyW|k Dz  
QG2 Zh9R  
//count++; D|Wlq~IpQ  
//if(count>4) D}j`T  
// siteStop(); cC+2%q B  
} `|nCnT'  

Pd(_  
tMp!MQ   
System.err.println("文件下载结束！"); {*[(j^OE
 
} { I\og  
catch(Exception e){e.printStackTrace ();} G -+!h4p  
} slUi)@b  
-B&(
&R  
gZ7R^] k  
//获得文件长度 /F(n%8)Yq  
public long getFileSize() W I MBwmg  
{ bv b\G  
int nFileLength = -1; z ynu0X  
try{ AX<f$%iqD  
URL url = new URL(siteInfoBean.getSSiteURL()); Y0A(-
"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;FRUB@:
 
httpConnection.setRequestProperty("User-Agent","NetFox"); uLWu. Vx  
.kn2M&P>=  
a#;;0R $  
int responseCode=httpConnection.getResponseCode(); #jW=K&;
 
if(responseCode>=400) TjYHoL5
 
{ &}
`a"tYr  
processErrorCode(responseCode); =!xX{o?64  
return -2; //-2 represent access is error q CYu@Ho  
}
wWiYxBeN  
PPIO<K 3`  
$?bD55  
String sHeader; L\E>5G;  
]+W){W=ai  
O=(F46 M  
for(int i=1;;i++) EwA*  
{ F P|cA^$<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *4}NLUVX
 
//Utility.log(in.readLine()); VJ&<6  
sHeader=httpConnection.getHeaderFieldKey(i); ,m5i(WL  
if(sHeader!=null)
p\lR1  
{ }$'_%,  
if(sHeader.equals("Content-Length")) E5M/XW\E6  
{ !]82$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |D"L!+J-$  
break; dS4zOz"  
} )H{1Xjh-  
} tHZ"o!(S  
else ^MF 2Q+  
break; L\:m)g,F.  
} ce}A!v  
} }6/M5zF3  
catch(IOException e){e.printStackTrace ();} H>+])~#  
catch(Exception e){e.printStackTrace ();} /pPHD]  
PQ[?zNrSV  
X )tH23  
Utility.log(nFileLength); h72/03!  
V3q`V/\  
hRu}P"  
return nFileLength; cK u[4D
{  
} k'#3fz\  
iC=>wrqY>  
MyllL@kP  
//保存下载信息（文件指针位置） 0#!
}s&j/  
private void write_nPos() @:GqOTN  
{ x]x3iFD  
try{ L'?aoRj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M-Efe_VRQc  
output.writeInt(nStartPos.length); L%is"NZh  
for(int i=0;i<nStartPos.length;i++) d$3md<lIB  
{ >{tn2Fkg>  
// output.writeLong(nPos); 6{=U= *  
output.writeLong(fileSplitterFetch.nStartPos); sIgTSdk  
output.writeLong(fileSplitterFetch.nEndPos); ]B=*p0~j^n  
} aq}hlA(w  
output.close(); EOXkMr  
} <KU0K  
catch(IOException e){e.printStackTrace ();} hQm=9gS  
catch(Exception e){e.printStackTrace ();} Sl,DZ!  
} ocZ}RI#Q  
o?>0WSLlm  
]$r]GVeN}H  
//读取保存的下载信息（文件指针位置） #xGP|:m  
private void read_nPos() j;]I -M[  
{ vHcl7=)Q  
try{ 6dr
'nP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l_Lz9k  
int nCount = input.readInt(); Y$v#>w_M  
nStartPos = new long[nCount]; G&{yM2:E  
nEndPos = new long[nCount]; p7;K] AW  
for(int i=0;i<nStartPos.length;i++) {\`ttc>  
{ D!,5j_,j%  
nStartPos = input.readLong(); >jhcSvM6  
nEndPos = input.readLong(); mnK<5KLg1  
} JR.)CzC  
input.close(); xOj#%;  
} v.Bwg7R3  
catch(IOException e){e.printStackTrace ();} C?gqX0[ q  
catch(Exception e){e.printStackTrace ();} HJ7A/XW  
} rCDt9o>  
]?@ [Ny=0  
Y:TfD{Xgc  
private void processErrorCode(int nErrorCode)
Q
jY}$  
{ =f!A o:Uc  
System.err.println("Error Code : " + nErrorCode); RxYENG]/6  
} %QEBY>|lI  
>ceC8"}J5M  
C`i#7zsH  
//停止文件下载 =|1_6.tz  
public void siteStop() KqntOo} y)  
{ n~ad#iN  
bStop = true; q&-mbWBj  
for(int i=0;i<nStartPos.length;i++) 6)uBUM;i  
fileSplitterFetch.splitterStop(); 5tbCx!tL  
+a.2\Qt2A  
*mp:#'  
} $5 mGYF]  
} Tty'ysH  
//负责部分文件的抓取 yO)xN=o^\  
**FileSplitterFetch.java ) ~=pt&+  
*/ B1 }-   
package NetFox; \{ EVRRXn  
@iuX~QA[9  
:k1?
I'q%  
import java.io.*; azv173XZ  
import java.net.*; )v_Wn[Y.H  
&SbdX  
Q/]~`S  
public class FileSplitterFetch extends Thread { cmXbkM  
piM4grg \  
$TXiWW+  
String sURL; //File URL S}JOS}\^j  
long nStartPos; //File Snippet Start Position l}L81t7f  
long nEndPos; //File Snippet End Position Pq [_(Nt  
int nThreadID; //Thread's ID DfAF-Yhut  
boolean bDownOver = false; //Downing is over 2.%)OC!q&5  
boolean bStop = false; //Stop identical (1D1;J4g  
FileAccessI fileAccessI = null; //File Access interface zb9G&'7  
D2&d",%&f  
JyE-
c}I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CjpGo}a/  
{ #G]IEO$M6  
this.sURL = sURL; GbQi3%  
this.nStartPos = nStart; !lNyoX/  
this.nEndPos = nEnd; ; oa+Z:;f  
nThreadID = id; vEg%ivj3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ak@!F6~  
} zJw5+ +  
C`;igg$t_  
0(-4"u>?  
public void run() BN79\rt  
{ )^o.H~Pv  
while(nStartPos < nEndPos && !bStop) ?m*e$!M0  
{ NuR7pjNMZ  
eWAD;x?.  
 `qs,V  
try{ I+kAy;2  
URL url = new URL(sURL); S~aWun  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {OPEW`F  
httpConnection.setRequestProperty("User-Agent","NetFox"); B3ItZojAuw  
String sProperty = "bytes="+nStartPos+"-"; PSq?8.  
httpConnection.setRequestProperty("RANGE",sProperty); Vt}QPNt  
Utility.log(sProperty); p}!i_P  
ASbIc"S6  
]`$yY5&W0  
InputStream input = httpConnection.getInputStream(); h s'
,f  
//logResponseHead(httpConnection); vz4( k/  
B.G6vx4yp  
s>6h]H  
byte[] b = new byte[1024]; HN5661;8  
int nRead; uluAqDz`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pCIS82L  
{ @)h>vg  
nStartPos += fileAccessI.write(b,0,nRead); Yg.[R] UC  
//if(nThreadID == 1) $4g
{4-)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o^2MfFS  
} Yt#; +*d5  
F0_w9"3E~  
x[{\Aw>$.  
Utility.log("Thread " + nThreadID + " is over!"); V_~lM
E  
bDownOver = true; &q<k0_5Q  
//nPos = fileAccessI.write (b,0,nRead); Nksm&{=6S  
} -b^dK)wR~  
catch(Exception e){e.printStackTrace ();} >} 2C,8N  
} e}?Q&Lci  
} bfA>kn0C  
[Kc?<3W  
j<kW+Iio  
//打印回应的头信息 Am*IC?@tq  
public void logResponseHead(HttpURLConnection con) B%\&Q@X  
{ _\\Al v.  
for(int i=1;;i++) ]\^O(BzB  
{ {BJ>x:2  
String header=con.getHeaderFieldKey(i); ]YI9  
if(header!=null) eX#.Zt]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &qg6^&  
Utility.log(header+" : "+con.getHeaderField(header)); yx|iZhK0:}  
else y-E'Y=j  
break; .@)vJtH)  
} L/rf5||@  
} P{A})t7  
M584dMM  
5{b;wLi$X2  
public void splitterStop() O;RBK&P  
{ *S*49Hq7c  
bStop = true; zk{d*gN  
} "e"#k}z9  
bss2<mqlH  
2
|bt"y-5r  
} kfnh1|D=aY  
X?t;uZI^  
$(D>v!dp  
/* 0~U%csPHt  
**FileAccess.java eaf-_#qb  
*//文件访问(定位，写) ]#G s6CsT|  
package NetFox; eAW)|=2  
import java.io.*; oVK:A;3T|  
a,oTU\m C  
FcM)v"bF&]  
public class FileAccessI implements Serializable{ K^<?LXJF  
H[.)&7M\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 cV6H!\  
RandomAccessFile oSavedFile; b, a7XANsh  
long nPos; 129\H< m  
U3&GRY|##  
}iKjef#J  
public FileAccessI() throws IOException >niv>+!N  
{ A2gFY}  
this("",0); j?u1\
<m  
} _3%$E.Q  
;7s^slVzF  
HFP'b=?`]|  
public FileAccessI(String sName,long nPos) throws IOException [j/|)cj  
{ 7_oUuNw  
oSavedFile = new RandomAccessFile(sName,"rw"); wuXQa wo  
this.nPos = nPos; H8w[{'Mei  
oSavedFile.seek(nPos); @H`jDaB9  
} sPQjB[  
S~:uOm2t\  
c"tlNf?  
public synchronized int write(byte[] b,int nStart,int nLen) yQ/O[(  
{ dUa>XkPa\2  
int n = -1; /g>-s&w  
try{ y%vAEQ2j=  
oSavedFile.write(b,nStart,nLen); q`p0ul,n  
n = nLen; Zo2+{a  
} }i^
M<A O  
catch(IOException e) *~P| ? D'  
{ ~OX\R"aZBW  
e.printStackTrace (); <J%Z?3@T  
} #EUT"^:d  
3\RD%[}  
,X3D<wl  
return n; 3A^AEO  
} kkZ}&OXS;  
L@O
>;zp;  
+PE-j| D  
} BC!) g+8  
C _he=SV  
=SmU;t>t/  
/* S}rEQGGR{  
**SiteInfoBean.java 1y:fH4V  
*/ s/@uGC0>  
package NetFox; pBe1:  
dCM&Yf}K  
MD$W;rk(Hn  
public class SiteInfoBean { mRAt5a#is  
k(RKAFjY  
;R0LJApey  
private String sSiteURL; //Site's URL B ZU@W%E  
private String sFilePath; //Saved File's Path +)yo
QRekX  
private String sFileName; //Saved File's Name [nHN@p|  
private int nSplitter; //Count of Splited Downloading File vmNo~clt\  
%Y0lMNP  
7Ku&Q<mi  
public SiteInfoBean() 1v:Ql\^cT  
{//nSplitter的缺省值为5 rPy,PQG2w  
//default value of nSplitter is 5 6t7FklM%  
this("","","",5); j.6!T'$|  
} c[2ikI,n[  
G HQ~{  

%?n=In(F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %|+aI?  
{ _YlyS )#@  
sSiteURL= sURL; K?,?.!ev
 
sFilePath = sPath; EG^ rh;  
sFileName = sName; #f(tzPD  
this.nSplitter = nSpiltter; ;/V])4=  
FWeUZI+  
 kVZs:  
} 3c#^@Bj(-e  
H.iCYD_=  
>A@yF?  
public String getSSiteURL() 8Ckd.HKpQ  
{ +a,#
BSt  
return sSiteURL; dpE^BWv3  
} h{"SV*Xpk/  
82 |^o  
"Ia.$,k9  
public void setSSiteURL(String value) J#H,QYnf(L  
{ yz0#0YG7  
sSiteURL = value; 5-0&`,  
} 8fi'"  
OU` !c[O  
I-8I/RRkmP  
public String getSFilePath() #*9 |\  
{ 'wFhfZB1!B  
return sFilePath; Xk!{UxQKQ  
} 0x5\{f  
<WWZb\"{  
OH`zeI,[*  
public void setSFilePath(String value) VFawASwQ  
{ FT>>XP8  
sFilePath = value; !W,LG$=/  
} -wH0g^Ed  
R#Yj%$E1  
61QA<Wb  
public String getSFileName() A#']e8  
{ ,)U%6=o#}  
return sFileName; eQyc<  
} SN")u  
^& *;]S`  
\c{sG\ >  
public void setSFileName(String value) oH4zW5  
{ \H>Psv{  
sFileName = value; MV3K'<Y  
} kz}Bc
F  
)$1j"mV  
s+_8U}R  
public int getNSplitter()
J*K=tA  
{ qYVeFSS  
return nSplitter; euV!U}Xr  
} 5`&@3 m9/  
4`o0?_.'  
vq9O|E3  
public void setNSplitter(int nCount) IDpLf*vSG  
{ `K@N\VM  
nSplitter = nCount; lxZ9y  
} {4SaSv^/  
} z^*g2J,  
}+S
~Ah?(  
*!%n`BR '  
/* sRBfLN2C  
**Utility.java :{S@KsPqE  
*/ .K-d
 
package NetFox; 7Q'u>o  
1NZp
d'$c  
EJz!#f~  
public class Utility { . WJ  
Q~Nq5[  
R$IsP,Uw  
public Utility() e\aW~zs2  
{ ;B2&#kot7  
rFt+Y})  
ro?.w  
} S{F\_'%  
[V8^}s}tF  
//线程睡眠 ^; U}HAY  
public static void sleep(int nSecond) )#4(4 @R h  
{ v5 p`=Z@%  
try{ (p'/a.bn  
Thread.sleep(nSecond);  HC
/a  
} wZCboQ,  
catch(Exception e) Fsq)co  
{ Jb9@U/<\  
e.printStackTrace (); ~ [/jk !G  
} h7.jWJTo  
} ;){ZM,Ox  
]fh(b)8_,  
//日志 I5[@C<b  
public static void log(String sMsg) +7lr#AvU/  
{ c>c4IQ&d  
System.err.println(sMsg); txMC^-J2l  
} E.N>,N  
s)3Co
sU  
2|1CGHj\  
public static void log(int sMsg) `B8`<3k/(  
{ <jFov`^  
System.err.println(sMsg); ZF#lh]  
} .*595SuF  
} \%}]wf}  
1W0[|Hf2v*  
;*nzb!u\\  
/* #@V<{/;49  
**TestMethod.java .2rpQa/h  
*/ ;sUvY*Bcm  
package NetFox; cw0@Z0  
#jxPh!%9  
is%ef  
public class TestMethod { 6_rgRo&  
JX>`N5s  
$
%&OaAg  
public TestMethod() {pre|r\  
{ ///xx/weblogic60b2_win.exe (B@\Dw8^  
try{ MR@Qn[RdM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0[uOKFgE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8WQc8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pfl^GgP#  
fileFetch.start(); XfIsf9  
} #{k+^7aQ  
catch(Exception e){e.printStackTrace ();} 8OS^3JS3"  
_\@zq*E  
,N_V(Cx5pt  
} 5[*8CY  
z~2;u5S&  
S;#7B?j  
public static void main(String[] args) !-SI &qy  
{ J5f}-W@  
new TestMethod(); KxhWZ3  
} vkYiO]y  
} g^=Ruh+  
点击下载更多相关资料