http断点续传简单实现（java)

/* 9-)D"ZhLe  
**SiteFileFetch.java # Vz9j  
*/
AF5.)Y@.  
package NetFox; GKf,1kns  
import java.io.*; RRh0G>*  
import java.net.*; WE""be8  
1U[8OM{$  
k.nq,  
public class SiteFileFetch extends Thread { u
,i~,M  
.6Jo1$+  
V_pWf5F  
SiteInfoBean siteInfoBean = null; //文件信息Bean P,y*H_@k  
long[] nStartPos; //开始位置 ^CZ!rOSv  
long[] nEndPos; //结束位置 (jYHaTL6Y'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S;#S3?G  
long nFileLength; //文件长度 @, v'V!  
boolean bFirst = true; //是否第一次取文件 (`+%K_  
boolean bStop = false; //停止标志 II$B"-  
File tmpFile; //文件下载的临时信息 #({0HFSC:j  
DataOutputStream output; //输出到文件的输出流 ZuIr=`"j  
4B>N[#-0=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8>" vAEf  
public SiteFileFetch(SiteInfoBean bean) throws IOException X`kTbIZ|  
{ #rSm;'%,  
siteInfoBean = bean;  QDCu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3@XkO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !6yoD  
if(tmpFile.exists ()) 0#}Ed Q  
{ x(J|6Ey7!n  
bFirst = false; ;=goIsk{Q  
read_nPos(); nX(2&<  
} >`Xikn(  
else oNHbQ&h  
{ Ua^#.K  
nStartPos = new long[bean.getNSplitter()]; hl`4_`3y  
nEndPos = new long[bean.getNSplitter()]; h}PeXnRU  
} ]?!#*<t r  
5U)Ia>p  
wZv"tbAWLV  
y8"8Q
H  
} b77
Iw%x7  
&NbhQY`k  
Le#>uWM  
public void run() ,CiN@T \&  
{ 0XV8B  
//获得文件长度 ?wzE+p-  
//分割文件 ~,[<R  
//实例FileSplitterFetch x6Q,$B  
//启动FileSplitterFetch线程 r;}%} /IX  
//等待子线程返回 LIfQh  
try{ @=CN#D12  
if(bFirst) = GUgb2TAT  
{ }7p`8?  
nFileLength = getFileSize(); ;&mefaFlWp  
if(nFileLength == -1) _*\:UBZx6  
{ Fc{M N"  
System.err.println("File Length is not known!"); )C^ZzmB  
}
) #G5XS+)  
else if(nFileLength == -2) chw6_ctR>  
{ W
k1o H  
System.err.println("File is not access!"); U .?N  
} MrXmX[1-  
else _P6e%O8C#  
{ 3[mVPV  
for(int i=0;i<nStartPos.length;i++) %JUD54bBt  
{ 5>z`==N)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8nzDLFxp_  
} OW}ny  
for(int i=0;i<nEndPos.length-1;i++) >bQ'*!  
{ -/ 5" Py  
nEndPos = nStartPos[i+1]; l":\@rm`  
} M<h2+0(il  
nEndPos[nEndPos.length-1] = nFileLength; fTb&k;'LR<  
}
z%ZAN-  
} "+SnHpNx  
\F`%vZrKR  
}HdibCAOf  
//启动子线程 } a#RX$d&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~z;G$jd  
for(int i=0;i<nStartPos.length;i++) Zb> UY8  
{ SUv(MA&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XcN"orAo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tf1iRXf8  
nStartPos,nEndPos,i); pC=kvve  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WC2sRv4]3  
fileSplitterFetch.start(); D^]g`V*N  
} .|ZO2MCd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1 Hw%DJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [2h4%{R&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", | ]#PF*  
nEndPos = " + nFileLength); IIj :\?r  
// fileSplitterFetch[nPos.length-1].start(); 6"@`iY  
jL^3/0"o  
GYp}V0  
//等待子线程结束 "d1~(0=6<m  
//int count = 0; Cp!bsasj  
//是否结束while循环 e`]x?t<U4/  
boolean breakWhile = false; k*xMe-  
d v8q&_  
2
'>   
while(!bStop) Y52f8qQq  
{ {|!> {  
write_nPos(); 2%!yV~Z  
Utility.sleep(500); r.WQ6h/eZ5  
breakWhile = true; Fa]|Y  
EA#{N<  
o8uak*"{  
for(int i=0;i<nStartPos.length;i++) yLpsK[)}\  
{ sVT:1 kI  
if(!fileSplitterFetch.bDownOver) qYba%g9RN(  
{ x:wv#Wh:l7  
breakWhile = false; B EN U  
break; Q)mYy
  
} NW=gi qB  
} 92F9)S{"  
if(breakWhile) (:|g"8mQm  
break; QOT|6)Yb  
&/+LY_r'<I  
V -X*e  
//count++; \mp2LICQg  
//if(count>4) BIQQJLu  
// siteStop(); +f
){x9 :  
} NeI#gJ1A  
>6X$iBb0
 
W!Qaa(o?  
System.err.println("文件下载结束！"); :OEovk(`  
} Vi9Kah+  
catch(Exception e){e.printStackTrace ();} xLN$!9t  
} ^*g= 65!1  
@zs.M-F  
@~ 6,8nQ  
//获得文件长度 uO^,N**R#  
public long getFileSize() \&XtPQ  
{ 
c^F@9{I  
int nFileLength = -1; jNbU{Z%r  
try{ ?1afW)`a.v  
URL url = new URL(siteInfoBean.getSSiteURL()); !(H RP9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vV PK  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8T523VI  
Pt=@U:  
j|-{*t{/x  
int responseCode=httpConnection.getResponseCode(); s#BSZP  
if(responseCode>=400) As>-9p>v  
{ X$A[~v  
processErrorCode(responseCode); 8"=E0(m  
return -2; //-2 represent access is error ?B{,%2+  
} yg WwUpY  
FlyRcj  
zkm#w  
String sHeader; # A#,]XP  
*L{^em#b  
r?%,#1|$$  
for(int i=1;;i++) rds4eUxe  
{ +*`>7m<^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k*
u4N  
//Utility.log(in.readLine()); M+l~^E0Wj  
sHeader=httpConnection.getHeaderFieldKey(i); 1lLXu  
if(sHeader!=null) -IE=?23Do?  
{ werTwe2Q  
if(sHeader.equals("Content-Length")) E0t%]?1  
{ 8+mu'RZ X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); W.sH  
break; /Z1>3=G by  
}
oAt{#v  
} {>h,@  
else ],|
;  
break; f\u5=!kjN  
} 9i`MUE1Sh  
} !*!i&0QC~R  
catch(IOException e){e.printStackTrace ();} fn3D
oD+I  
catch(Exception e){e.printStackTrace ();} /P[@o  
@W.0YU0|J  
D6fGr$(N%  
Utility.log(nFileLength); BJP^?FUd=,  
}$oZZKS  
\R.Fmeko  
return nFileLength; ,<O|#`?"@G  
} k vF[d{l
 
W@t{pXwLv  
OI)U c .  
//保存下载信息（文件指针位置） 1SG^g*mf  
private void write_nPos() zbZN-j#  
{ g0M/Sv  
try{ V8947h|&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i Qa=4'9;  
output.writeInt(nStartPos.length); ;mauA#vd  
for(int i=0;i<nStartPos.length;i++) c:u2a/Q?  
{ y{9<>28  
// output.writeLong(nPos); [pzo[0G 'v  
output.writeLong(fileSplitterFetch.nStartPos); S{S.H?{F  
output.writeLong(fileSplitterFetch.nEndPos); k/m-jm_h  
} _zG[b/:p  
output.close(); xX~; /e&,  
} Gj- *D7X5  
catch(IOException e){e.printStackTrace ();} |bX{MF  
catch(Exception e){e.printStackTrace ();} F3=iyiz6  
} ? oQ_qleuo  
*?R<gWCF  
gE$@:j  
//读取保存的下载信息（文件指针位置） AcIw; c:  
private void read_nPos() K*aGz8N  
{ JQ<9~J  
try{ 4mci@1K#^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U&OE*dq  
int nCount = input.readInt(); `{+aJ0<S  
nStartPos = new long[nCount]; >U62vX"  
nEndPos = new long[nCount]; X8~gLdv8  
for(int i=0;i<nStartPos.length;i++) I,7n-G_'  
{ oL
c  
nStartPos = input.readLong(); FQBAt0  
nEndPos = input.readLong(); ~+&Z4CYb  
} 4*
?JU v  
input.close(); 9t"/@CH{  
} 0#!Z1:Y  
catch(IOException e){e.printStackTrace ();} QN8.FiiD  
catch(Exception e){e.printStackTrace ();} ~+anI  
} Ixr#zt$T-G  
7b hJt_`Q  
^2e
H0O!  
private void processErrorCode(int nErrorCode) OcZ8:`=%  
{ FQO>%=&4  
System.err.println("Error Code : " + nErrorCode); 8gXf4A(N  
} ~Aoo\fN_U  
e)kVS}e?  
vFH1hm  
//停止文件下载 (k<__W c_t  
public void siteStop() (T8dh|  
{ X@^"@  
bStop = true; N6uKFQL:{  
for(int i=0;i<nStartPos.length;i++)
4L/8Hj#g  
fileSplitterFetch.splitterStop(); Z:Nm9m  
k(R&`  
\Z/#s;c,4  
} i1-wzI  
} !--A"  
//负责部分文件的抓取 r=:o$e  
**FileSplitterFetch.java "dFuQB  
*/ zf?U q  
package NetFox; a{! 8T  
1'YksuYx6f  
f4lC*nCN  
import java.io.*; ky{-NrK  
import java.net.*; DtOL=m]s  
dH+o
V`  
.Eg[[K_iD  
public class FileSplitterFetch extends Thread { "V:E BR  
1ZRSeh  
['\u?m  
String sURL; //File URL {U7A&e0eW  
long nStartPos; //File Snippet Start Position mqKr+  
long nEndPos; //File Snippet End Position Fa9gr/.F,@  
int nThreadID; //Thread's ID |<w Z;d  
boolean bDownOver = false; //Downing is over 4<l&cP  
boolean bStop = false; //Stop identical p WLFJH}N  
FileAccessI fileAccessI = null; //File Access interface /+{1;}AT  
O>Ao#_*hOb  
+
EP=uV9t  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException > @n?W"  
{ zR6^rq*  
this.sURL = sURL; %#-'|~  
this.nStartPos = nStart; 6),VN>j  
this.nEndPos = nEnd; FX:'38-fk  
nThreadID = id; &dvL`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K0z@gWGE  
} ;(~H(]D  
P'p5-l UK  
[y1 x`WOk9  
public void run() [cvtF(,  
{ JN<IMH  
while(nStartPos < nEndPos && !bStop) "M4gl  
{ Ilv
_.  
_5SA(0D#9  
"%fvA;  
try{ =d`/BDD  
URL url = new URL(sURL); ui4*vjd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
qFg"!w  
httpConnection.setRequestProperty("User-Agent","NetFox"); YDdY'd`*  
String sProperty = "bytes="+nStartPos+"-"; g9oYK  
httpConnection.setRequestProperty("RANGE",sProperty); TP?HxO_C  
Utility.log(sProperty); N cnL-k.  
23JuuV.  
r-IG.ym3  
InputStream input = httpConnection.getInputStream(); t*cVDA&K  
//logResponseHead(httpConnection); 6n5>{X  
HA::(cXL  
G,JK$j>*l  
byte[] b = new byte[1024]; 3m59EI-p  
int nRead; -3eHJccB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) = *~Q5F  
{ IiRII)  
nStartPos += fileAccessI.write(b,0,nRead); {wyf>L0j  
//if(nThreadID == 1) n 2m!a0;
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {ZrB,yK  
} aIW W[xZ  
v#o<. Ig  
{fAj*,pzl  
Utility.log("Thread " + nThreadID + " is over!"); fY{&W@#g  
bDownOver = true; 'k9dN \ev  
//nPos = fileAccessI.write (b,0,nRead); (b4;c=<[{  
} @gHWU>k,A  
catch(Exception e){e.printStackTrace ();} - |j4u#z  
} Ss c3uo0  
} 2$%E:J+2:$  
@N,I}_9-  
okv`v ({  
//打印回应的头信息 Fu6~8uDV{{  
public void logResponseHead(HttpURLConnection con) EABy<i  
{ RmcQGQ
 
for(int i=1;;i++) X'KkIo :  
{ rP7~R  
String header=con.getHeaderFieldKey(i); Bq)aA)gF  
if(header!=null) d:1TSJff%/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Nw=mSW^E  
Utility.log(header+" : "+con.getHeaderField(header)); s0bWg$  
else yqKERdm  
break; *cnxp-)ub  
} AB1,G|L  
} 1} h''p  
XI*cu\7sy  
f0,,<ib.w
 
public void splitterStop() 1L:sck5k  
{ +Xjevg6DU  
bStop = true; gjnTG:}}}+  
} _Z
D8/?2QV  
T($6L7 j9  
N&'05uWY}  
} bcCCvV}6WZ  
H^\2,x Z  
sHi*\  
/* `OWw<6`k  
**FileAccess.java U)g27*7
  
*//文件访问(定位，写) HLml:B[F(  
package NetFox; >!7\Rx  
import java.io.*; JSOgq/\  
/>E:}1}{  
3(/J(8  
public class FileAccessI implements Serializable{ gkN )`/`*  
!YCus;B~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @3@oaa/v  
RandomAccessFile oSavedFile; [J71aH  
long nPos; 95%, 8t  
aE'nW@YL
.  
#0wH.\79  
public FileAccessI() throws IOException %Yi^{ZrM  
{ pg;y\}  
this("",0); 2|C(|fD4  
} "/MA.zEl0,  
v1Wz#oP  
16N+  
public FileAccessI(String sName,long nPos) throws IOException WMw]W&  
{ MU/3**zoW  
oSavedFile = new RandomAccessFile(sName,"rw"); _RcFV  
this.nPos = nPos; C
YCG5)<9  
oSavedFile.seek(nPos); L[s8`0  
} KnjowK  
4v("qNw#  
}co*%F{1  
public synchronized int write(byte[] b,int nStart,int nLen) RN0=jo!58  
{ Z<,$XvL  
int n = -1; <#r/4a"V  
try{ [V-OYjPAx  
oSavedFile.write(b,nStart,nLen); ao(l
j  
n = nLen; |{G GATni  
} YrWC\HR_  
catch(IOException e) jQc.@^#+x  
{ &/7D4!N]  
e.printStackTrace (); 7^|,l  
} 
ZLRAiL  
g)@d(EYY  
UZ"jQJQ  
return n; n2#Yw}7^,o  
} e<;^P(g`E  
68k  
_,m|gr,S  
} XA*sBf  
#~Z55D_  
_Ka6! 9  
/* D'!
v9}  
**SiteInfoBean.java v>&sb3I  
*/ m.K@g1G  
package NetFox; ^XIVWf#`H  
;=?f0z<  
dmkd.aP4  
public class SiteInfoBean { Zoi\r  
l1h;ng6  
g[d.lJ=Q-N  
private String sSiteURL; //Site's URL V>YZ^>oeH  
private String sFilePath; //Saved File's Path Ym WVb  
private String sFileName; //Saved File's Name Y,%d_yR
[  
private int nSplitter; //Count of Splited Downloading File -!kfwJg8N(  
=h<LlI^v  
v_$'!i$  
public SiteInfoBean() 4CT _MAj  
{//nSplitter的缺省值为5 > (.V(]{3y  
//default value of nSplitter is 5 _FJ,, /~  
this("","","",5); Zss `##  
} !7KSNwGu  
d
,R  
'K9{xI@N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CfWtCA  
{ APC,p,"  
sSiteURL= sURL; BV8-\R@  
sFilePath = sPath; ?1G7=R  
sFileName = sName; d? Old  
this.nSplitter = nSpiltter; lhk[U!>#  

.|pyloL.  
u6,NQ^4  
} I,:R~^qJ8v  
@DYxDap{  
EPZ^I)  
public String getSSiteURL() FccT@,.F  
{ .[E"Kb}=  
return sSiteURL; &s|a\!>l  
} x'.OLXx>  
z`^DQ8+\j  
?)ROQ1-#@  
public void setSSiteURL(String value) g@<E0 q&`$  
{ bHi0N@W!vG  
sSiteURL = value; 4K(AXk  
} z/,qQVv=}4  
1ud+~y$K  
=ca<..yh[d  
public String getSFilePath() WI?iz-,](  
{ 7I,/uv?  
return sFilePath; L6xLD X7y  
} UA{tmIC\  
h#o3qY  
]7d~,<3R  
public void setSFilePath(String value) Kc>C$}/}$  
{ x1$:u6YD22  
sFilePath = value; mv,<#<-W  
} "K"]/3`k-  
A
V%?8-  
cNX0.7Ls  
public String getSFileName() [^cflmV  
{ d=TZaVL$$  
return sFileName; x tJ_azt  
} %|3I|'%Y  
Aj9Onz,Lg  
;}t
EU'&  
public void setSFileName(String value) v[aFSXGj)  
{ :DxCjv  
sFileName = value; YSvZ7G(m>  
} '%u7XuU-]  
r@2{>j
8  
jWg7
RuN  
public int getNSplitter() }SdI _sLe  
{ g"60{  
return nSplitter; |HjoaN)  
} `ehZ(H}  
<O5r|  
,Tb~+z|-[  
public void setNSplitter(int nCount) wX0m8"g@  
{ 5&y;r  
nSplitter = nCount; \,w*K'B_Y  
} zH1pW(  
} 5kK:1hH
7  
gbf-3KSp^  
MpV
3.  
/* ]kN<N0;\d  
**Utility.java ?y] q\>  
*/ 62R94  
package NetFox; {M7`z,,[  
JH%^FF2  
[|=#~(yYQ  
public class Utility {
-`iXAyr)m  
Y7vTs
eq  
 Nn"[GB  
public Utility() IZ$7'Mo86  
{ BVKr
2v  
"5KJ /7q!  
g1je':  
} t8"*jt  
CO
E,pb17  
//线程睡眠 +s*OZ6i [  
public static void sleep(int nSecond) %TY;}V59b  
{ fQ\nK H~  
try{ !n=?H1@  
Thread.sleep(nSecond); NhI&
wl  
} D# $Fj  
catch(Exception e) BZ]6W/0  
{ !besMZ  
e.printStackTrace (); ;B35E!QJ  
} re\@v8w~  
} LqH<HGMFD  
*H"IW0I  
//日志 (1 "unP-  
public static void log(String sMsg) 19Cs 3B\4  
{ 3'd(=hJ45$  
System.err.println(sMsg); ){AtV&{$  
} pJ` M5pF  
A9*( O)  
h,Y!d]2w  
public static void log(int sMsg) Quc,,#u  
{ yGNZw7^(  
System.err.println(sMsg); 7,i}M  
} *wgHa6?+7  
} Q}KNtNCpx  
5E~?hWAv  
iqzl(9o.D  
/* sr0.4VU1  
**TestMethod.java F{#m~4O  
*/ LQ,RQ
~!  
package NetFox; w/8`]q  
xbh4j!FD$  
l7 +#gPA  
public class TestMethod { Di[}y;  
-BY'E$]4  
bYuQ"K A$  
public TestMethod() 0_}^IiG  
{ ///xx/weblogic60b2_win.exe wq[\Fb`  
try{ [0_JS2KE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `EV"
/&`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a@|/D\C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R^}}-Dvr  
fileFetch.start(); G}o?lo\#h  
} L<kIzB !  
catch(Exception e){e.printStackTrace ();} )Ir_:lk  
$/\b`ID  
T ;Ga G  
} NDw+bR-  
59?@55  
4?#0fK  
public static void main(String[] args) u!k]Q#2ZR  
{ <b-BJ2],k  
new TestMethod(); \JJ
>y  
} "
2>I?  
} 0jS"PH?[  
点击下载更多相关资料