http断点续传简单实现（java)

/* !LIfeL.4h  
**SiteFileFetch.java _*ouo<x  
*/ rk,1am:cg  
package NetFox; g~c|~u(W  
import java.io.*; Tj21YK.mk  
import java.net.*; &s^>S?L-  
Ogke*qM  
%y\eBfW,/  
public class SiteFileFetch extends Thread { 72ViPWW  
Kq 4<l  
n_aNs]C9R  
SiteInfoBean siteInfoBean = null; //文件信息Bean W0MnGzZ  
long[] nStartPos; //开始位置 mH*@d"  
long[] nEndPos; //结束位置 2Uv3_i<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (vAv^A*i}  
long nFileLength; //文件长度 Ivt} o_b*  
boolean bFirst = true; //是否第一次取文件 L>Oy7w)Y  
boolean bStop = false; //停止标志 gJ5
wAK+?  
File tmpFile; //文件下载的临时信息 )@bH"  
DataOutputStream output; //输出到文件的输出流 +#qt^NO  
8| e$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9;]wF8h  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5Z6-R}uXk  
{ .pIR/2U\F  
siteInfoBean = bean; e(w/m(!Wny  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); { w8 !K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qE`:b0FT  
if(tmpFile.exists ()) =Esbeb7P  
{ ,t%CK!8  
bFirst = false; ?S@R~y0K  
read_nPos(); <Hh5u~  
} JC&6q>$  
else )y`TymM[F  
{ 1rv$?=Z  
nStartPos = new long[bean.getNSplitter()]; ,.oa,sku  
nEndPos = new long[bean.getNSplitter()]; r'd:SaU+  
} S@
c\|  
x'2 ,sE  
q)?p$\  
O+o;aa6  
} 4aN+}TkH@G  
nR o=J5tY  
X"k^89y$  
public void run() 'Gl;Ir^  
{ ?UZ$bz  
//获得文件长度 :_^0'ULP  
//分割文件 4\1wyN /}M  
//实例FileSplitterFetch b~/Wnp5  
//启动FileSplitterFetch线程 AJ\VY;m7F  
//等待子线程返回 D(qHf9  
try{ P(pd0,%i;a  
if(bFirst) ]HyHz9QkL  
{ CO:*x,6au  
nFileLength = getFileSize(); L{2
b0Zh'  
if(nFileLength == -1) U
6juS/  
{ #u8*CA9  
System.err.println("File Length is not known!"); 0):uF_t<  
} dv^e9b|  
else if(nFileLength == -2) $-$5ta{s  
{ v~V;+S=gz  
System.err.println("File is not access!"); X:G&5  
} [_ M6/  
else -_2Dy1  
{ (Bt;DM#>  
for(int i=0;i<nStartPos.length;i++) .'5
'0lR5  
{ 8Wdkztp/S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~VqFZasV  
} yX7CN5vVl  
for(int i=0;i<nEndPos.length-1;i++) 
n5bXQ  
{ #)_J)/h  
nEndPos = nStartPos[i+1]; _8[UtZYG  
} y _'eyR@)  
nEndPos[nEndPos.length-1] = nFileLength; C~ZE95g  
} 3VcT7y*{P  
} X)Dqeb6  
UsLh)#}h  
9m\)\/V  
//启动子线程 S9G8aea/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BgJkrv7~  
for(int i=0;i<nStartPos.length;i++) m x3}m?W
Q  
{ [as-3&5S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oMh~5 W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0\5M^:8i3  
nStartPos,nEndPos,i); g|ql 5jW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FNz84qVIx'  
fileSplitterFetch.start(); 3TU'*w &  
} 7o;x
(9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >"cr-LB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ljup#:n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nU}~I)@V  
nEndPos = " + nFileLength); CV!;oB&  
// fileSplitterFetch[nPos.length-1].start(); OM20-KDc5  
qs!>tw  
kF+ZW%6N  
//等待子线程结束 EkRdpiLB  
//int count = 0; Q&u>7_, Du  
//是否结束while循环 Az U|p  
boolean breakWhile = false; '"` Lv/  
968Ac}OA  
4)c+t"h  
while(!bStop) D3%l4.h  
{ T@(6hEmP,  
write_nPos(); PSW#^o  
Utility.sleep(500); R'G'&H{N  
breakWhile = true; xik`W!1S  
} c{Fa&  
=a?a@+  
for(int i=0;i<nStartPos.length;i++) ':,>eL#+uV  
{ UskZ%J  
if(!fileSplitterFetch.bDownOver) /GsSrP_?]  
{ o*%3[HmV  
breakWhile = false; uyL72($  
break; &}zRH}s;  
} =MMCf0  
} HS{P?~:=U  
if(breakWhile) M'^(3#ZU  
break; HjV\lcK:v  
*I=_*LoG2  
-"F0eV+y  
//count++; |xq}'.C  
//if(count>4) 9n_ eCb)H  
// siteStop(); ha_@Yqgh  
} IK8%Q(.c  
+jc
df}  
4w@v#H@  
System.err.println("文件下载结束！"); N%O
[  
} >P(eW7RL  
catch(Exception e){e.printStackTrace ();} :OHSxb>[  
}  q4_**  
BpH|/7  
e:qo_eSC^-  
//获得文件长度 0HjJaML  
public long getFileSize() {b
(rm,%  
{ ?LM:RADCm  
int nFileLength = -1; e d_m +NM  
try{ ll_}&
a0G  
URL url = new URL(siteInfoBean.getSSiteURL()); fb/qoZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LxB&7  
httpConnection.setRequestProperty("User-Agent","NetFox"); E\w+kAAf  
w-lrnjs  
^Ss<X}es-  
int responseCode=httpConnection.getResponseCode(); !@( M_Z'  
if(responseCode>=400) 2.]~*7   
{ P!5Z]+B#  
processErrorCode(responseCode); Bk+{}  
return -2; //-2 represent access is error P2>:p%Z
  
} zgK;4 22$m  
8AryIgy>@  
D^nxtuT*  
String sHeader; 658\#x8|  
ja?s@Y}-9s  
VW{,:Ya  
for(int i=1;;i++) .
XIr?>G  
{ EVG"._I@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `%uK0qw"  
//Utility.log(in.readLine()); l7ZB3'  
sHeader=httpConnection.getHeaderFieldKey(i); (JWv *p  
if(sHeader!=null) Q2q|*EL  
{ D{>\-]\  
if(sHeader.equals("Content-Length")) N50fL  
{ sqT^t!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6Hda]y  
break; #aa1<-&H  
}
rxs8De  
} A$Wx#r7)  
else 6>s=CiZB  
break; pOKeEW<q  
} =9(tsB gTX  
} ^L ]B5,}-  
catch(IOException e){e.printStackTrace ();} N^lAG"Jao[  
catch(Exception e){e.printStackTrace ();} wajZqC2yg  
M</Wd{.g"  
p/N62G  
Utility.log(nFileLength); +SyUWoM  
4HW;  
)XpVu  
return nFileLength; /V#7=,,  
} G,B?&gFX  
r4EoJyt  
~zMDY F"&  
//保存下载信息（文件指针位置） *(icR  
private void write_nPos() Z&A0hI4d  
{ >zFD$  
try{ B_cgWJ*4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :Z[(A"dA  
output.writeInt(nStartPos.length); a/b92*&k  
for(int i=0;i<nStartPos.length;i++) k
B V/rw  
{ >{b3>s~T  
// output.writeLong(nPos); Uh}+"h5  
output.writeLong(fileSplitterFetch.nStartPos); nW11wtiO.  
output.writeLong(fileSplitterFetch.nEndPos); g**5z'7  
} 3
tF:  
output.close(); vnL?O8`c  
} JxHv<p[  
catch(IOException e){e.printStackTrace ();} T!(sZf  
catch(Exception e){e.printStackTrace ();} T
ywK\hH  
} .D!WO  
w]}f6VlEl  
^(DL+r,  
//读取保存的下载信息（文件指针位置） s@PLS5d"  
private void read_nPos() QypZH"Np  
{ \ZsP]};*  
try{ Ts#pUoE~+H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wa<-AZn
h  
int nCount = input.readInt(); 9ZhDZ~)p,  
nStartPos = new long[nCount]; %P;[fJ `G  
nEndPos = new long[nCount]; QAi1,+y]7w  
for(int i=0;i<nStartPos.length;i++) ;5N41_hG  
{ ^;4YZwW5w  
nStartPos = input.readLong(); a5)JkC  
nEndPos = input.readLong(); B>,A(X&  
} q=+wI"[  
input.close(); T=>vh*J  
} me:iQ.g
 
catch(IOException e){e.printStackTrace ();} \+9;!VWhl  
catch(Exception e){e.printStackTrace ();} L?Cjo4xS  
} l/QhD?)9  
&y\igX1  
f]]f
85  
private void processErrorCode(int nErrorCode) L0xsazX:x  
{ pr/'J!{^  
System.err.println("Error Code : " + nErrorCode); K'V 2FTJI  
} i(Vm!Y82  
7VY8CcL  
`H"vR:~{  
//停止文件下载 onib x^Fcd  
public void siteStop() uRpBeH]Z"  
{ S2Vxe@b)  
bStop = true; F)7j@h^
 
for(int i=0;i<nStartPos.length;i++) Cx,-_  
fileSplitterFetch.splitterStop(); <S&]$?`{Wi  
5e8xKL  
ki#bPgT  
} )'t&q/Wn  
} J)KnE2dw5  
//负责部分文件的抓取 ;Gh>44UM[  
**FileSplitterFetch.java {:$NfW  
*/ =W<[Fe3  
package NetFox; tH,sql)  
7gr^z)${J  
GL`tOD:P"  
import java.io.*; 0#^Bf[Dn  
import java.net.*; Z0W0uP;J  
2LC w*eT{)  
N8QH*FX/F1  
public class FileSplitterFetch extends Thread { TaWaHf  
-x5F;d}  
.:N:pWe  
String sURL; //File URL _JA:.V^3gm  
long nStartPos; //File Snippet Start Position !=y Q)l2  
long nEndPos; //File Snippet End Position @h9K  
int nThreadID; //Thread's ID ol
}`Wwy  
boolean bDownOver = false; //Downing is over %I0}4$  
boolean bStop = false; //Stop identical &Sa~/!
M  
FileAccessI fileAccessI = null; //File Access interface 7D
9]R#-K  
1yS&~ y?a  
QAUykS8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o} {-j  
{ t#~XLCE  
this.sURL = sURL; _*n)mlLln  
this.nStartPos = nStart; e=L*&X  
this.nEndPos = nEnd; \XDmK  
nThreadID = id; h$/JGm5uDb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H?{MRe  
} a'A s
 
QF&6?e06p0  
]
'UgZsJ  
public void run() NNp}|a9  
{ _#vGs:-x&  
while(nStartPos < nEndPos && !bStop) wASX\D }  
{ GFt1  
gyFr"9';c  
\Z'/+}^h  
try{ aj v}JV&:  
URL url = new URL(sURL); tah
}^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .1{l[[= W  
httpConnection.setRequestProperty("User-Agent","NetFox"); R;'?;I  
String sProperty = "bytes="+nStartPos+"-"; )qd={  
httpConnection.setRequestProperty("RANGE",sProperty); 2vvh|?M  
Utility.log(sProperty); C`EY5"N r  

P5P<"  
tR;{.  
InputStream input = httpConnection.getInputStream(); q5?{1  
//logResponseHead(httpConnection); O5OXw]  
}hq^+fC?  
IM]h*YV'  
byte[] b = new byte[1024]; O8y9dX-2  
int nRead; C=[A
e,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Fv@tD4I>  
{ U{HML|  
nStartPos += fileAccessI.write(b,0,nRead); HzEGq,.  
//if(nThreadID == 1) ^/<|f,2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )#PtV~64  
} snq;:n!  
j%WY ,2P  
Ro~fvL~Ps  
Utility.log("Thread " + nThreadID + " is over!"); e96#2A5f  
bDownOver = true; [zx|eG<&-  
//nPos = fileAccessI.write (b,0,nRead); #Qsk}Gv  
} X Ny Y$  
catch(Exception e){e.printStackTrace ();} 1a*6ZGk.  
} Xb0!( (A  
} x=vK EyS@  
l=NAq_?N\  
70=(.[^+  
//打印回应的头信息 M}KZG'7  
public void logResponseHead(HttpURLConnection con) ?S9Nm~vlt  
{ ;h9W\Se  
for(int i=1;;i++) z{/LX \  
{ tvT4S  
String header=con.getHeaderFieldKey(i); B%mtp;) P  
if(header!=null) D:)~%wu Lt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OEI3eizgH  
Utility.log(header+" : "+con.getHeaderField(header)); XR+rT  
else #<]Iz'\`  
break; Wp`C:H  
} 3C#RjA-2[  
} zb?kpd}r  
7*MU2gb  
"
qE {a>d  
public void splitterStop() 3(o7co-f  
{ fB7ljg  
bStop = true; <5k&)EoT  
} F^miq^K=  
DyIV/  
-!~vA+jw1  
} OW#_ty_ul  
b|6!EGh  
SBz/VQ  
/* >>j+LRf*  
**FileAccess.java i pwW%"6  
*//文件访问(定位，写) qw2)v*Fn  
package NetFox; XECikld>  
import java.io.*; #@E(<Pu4`  
4]EvT=Ro  
SM
$\;)L  
public class FileAccessI implements Serializable{ g}YToOs  
B*2{M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >]-<uT_  
RandomAccessFile oSavedFile; p7$3`t6u  
long nPos; )tvc/)&A}  
_0m}z%rI  
F^]aC98]1  
public FileAccessI() throws IOException -F1P28<?  
{ 0$l&i=L  
this("",0); "vsjen.K>  
} V(Dj
F=8  
F^xaz^=`u  
R}hlDJ/m-  
public FileAccessI(String sName,long nPos) throws IOException Y&:/~&'  
{ ^Eu_NUFe  
oSavedFile = new RandomAccessFile(sName,"rw"); K#@
K"N=  
this.nPos = nPos; r_q~'r35_  
oSavedFile.seek(nPos); F  "!`X#  
} RPY6Wh|4  
umryA{Ps  
f}%sO  
public synchronized int write(byte[] b,int nStart,int nLen) ?;fv!'?%  
{ GBW 7Y  
int n = -1; 9>I
sqYc  
try{ 'f8 p7_F  
oSavedFile.write(b,nStart,nLen); kR_E6Fl  
n = nLen; .01TTK*  
} .T{U^0 )  
catch(IOException e) >pnz_MQ  
{ :/~_sJt C  
e.printStackTrace ();  X
tR`?  
} eWw y28t  
T%w(P ^qk  
y/H8+0sEk  
return n; gsi<S6DQ8  
} A>5S]  
F=VoFmF@  
a0 qj[+  
} /CbkqNV  
r&=r/k2  
WFXx70n  
/* Xz" JY
 
**SiteInfoBean.java 9'l.TcVm`,  
*/ kr6:{\DU:B  
package NetFox; |NXFla  
ypxC1E  
4">84,-N  
public class SiteInfoBean { N*? WUn9]  
CO7CNN  
)|Jr|8  
private String sSiteURL; //Site's URL :ECw \_"0$  
private String sFilePath; //Saved File's Path C>M6&=  
private String sFileName; //Saved File's Name f&f[La  
private int nSplitter; //Count of Splited Downloading File wH#Lb@cfZ0  
|O2|
`"7  
=\*S'Ded  
public SiteInfoBean() *SWv*sD  
{//nSplitter的缺省值为5 V.+DP  
//default value of nSplitter is 5 -B",&yTV  
this("","","",5); 2zwuvgiZ  
} XNy:0C  
MuN[U17FB  
+h9`I/R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !P+~c0DF  
{ O'Vh{JHf  
sSiteURL= sURL; ?NQD#  
sFilePath = sPath; 6CCZda@  
sFileName = sName; @ $9m>6V  
this.nSplitter = nSpiltter; *'s&/vEy  
?|\0)wrRf  
DM+sjn  
} aIY$5
^x  
[sjrb?Xd  
oVAOGHE  
public String getSSiteURL() F@oT7NB/n  
{ VNr!|bp5  
return sSiteURL; |P^ikx6f5  
} HdDo&#  
!N@Yh"c  
Z8N@e<!*~8  
public void setSSiteURL(String value) "~B~{ _<j  
{ ^Jc$BMaVg  
sSiteURL = value; &?&'"c{;m  
} HrM)jC<~  
AN50P!FZW  
\nn56o@eN  
public String getSFilePath() iLc)"L-i  
{ ~]jx+6k]  
return sFilePath; N.ItyV  
} i+kFL$N  
"0p +SZ~D  
q=(M!9cE  
public void setSFilePath(String value) t"jIfU>'a/  
{ o%y+Y;|?J  
sFilePath = value; 
bL6L-S  
} ufHuI*  
6yV5Yjs  
ot&j HS'  
public String getSFileName() ;))[P_$zB  
{ :T8u?@.  
return sFileName; qen44;\L  
} WMt&8W5  
~7FEY0/  
^' edE5  
public void setSFileName(String value) /TR"\xQF  
{ qJe&jLZa  
sFileName = value; i'[n`|c<  
} HPv&vdr3  
[J[ysW})W  
9u-M! $  
public int getNSplitter() i!/h3%=  
{ I_R5\l}O+D  
return nSplitter; 7=9A_4G!  
} QH~8 aE_i  
~)oWSo5ll  
b6rzHnl{  
public void setNSplitter(int nCount) d|D'&&
&c  
{ -;W\f<q]  
nSplitter = nCount; G~Q*:m  
} 8Iqk%n~(  
} w>1l@%Uo  
+?J_6Mo@X  
,4h!"c  
/* #L).BM  
**Utility.java js%4;  
*/ }kgjLaQ^N  
package NetFox; %BT)oH}  
QBN=l\m+  
$A5B{2  
public class Utility { soFvrl^Ql+  
@eAGN|C5  
Q}k_#w  
public Utility() 7k[`]:*o  
{ dd @COP?  
+w_MSj#P  
J"a2 @S&  
} @5dBb+0J  
&D&5UdN x  
//线程睡眠 PG-cu$\??  
public static void sleep(int nSecond) VLwJ6?.f'  
{ ePu2t3E  
try{ Y;%R/OyWY  
Thread.sleep(nSecond); ajcPt]f  
} KqG$zC^N  
catch(Exception e) ` i^`Q  
{ ?()E5 4y  
e.printStackTrace (); ]ZU:%Qhu  
} KY(l<pm  
} [W8iM7D  
Rzn0-cG  
//日志 8gu7f;H/k  
public static void log(String sMsg) 
#7cf 8y  
{ F(J!dG5#  
System.err.println(sMsg); %'D:bi5  
} 4p/V6kr&r  
@zq\z$  
S3JygN*  
public static void log(int sMsg) dKN3ZCw*gF  
{ TnZc.  
System.err.println(sMsg); l,FG:"`Z@  
} SjNwT[.nr7  
} G+\~rl  
!]jNVg  
* zJiii  
/* M%Kx{*aw&  
**TestMethod.java 'piF_5(@  
*/ B2Awdw3=g  
package NetFox; S|u1QGB  
,:Rq  
6lH>600]u  
public class TestMethod { @Tm0T7C  
EssUyF-jwU  
-$!Pf$l@  
public TestMethod() Af! W K=  
{ ///xx/weblogic60b2_win.exe 7+2aG  
try{ *F4G qX3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6u]OXPA|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XH Zu>[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *z;N  
fileFetch.start(); lG^mW\O  
} L-X _b3E\  
catch(Exception e){e.printStackTrace ();} #D*J5k>2  
*7D$;?"  
uvK%d\d  
} fU){]YP  
;H#R{uR_<  
]6c2[r?g{  
public static void main(String[] args) %onAlf<$:^  
{ uhN
(`E@  
new TestMethod(); l.W1$g  
} %~v76;H<  
}
4@V<Suw  
点击下载更多相关资料