http断点续传简单实现（java)

/* C\ tprnY  
**SiteFileFetch.java 2ck4C/ h  
*/ m23+kj)+VY  
package NetFox; vu=me?m?(  
import java.io.*; J , V  
import java.net.*; / /'Tck  
O7%2v@j|8  
*n8%F9F  
public class SiteFileFetch extends Thread { W4(v6>5l  
#O"  
eqq`TT#
Z  
SiteInfoBean siteInfoBean = null; //文件信息Bean "NDxgJ%J35  
long[] nStartPos; //开始位置 3{KR {B#L  
long[] nEndPos; //结束位置 n|Pr/ddL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [QT1Ju64  
long nFileLength; //文件长度 s2FngAM;f  
boolean bFirst = true; //是否第一次取文件 =+Im*mgNn  
boolean bStop = false; //停止标志 'n0 .#E_  
File tmpFile; //文件下载的临时信息 'B_\TU0 O  
DataOutputStream output; //输出到文件的输出流 9IA$z\<<w  
.-0%6] cFD  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） . V$ps-t  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3J{vt"dS  
{ $<|ocUC7  
siteInfoBean = bean; ;#TaZN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mffIf1f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &-%X:~|:X  
if(tmpFile.exists ()) Y#FO5O%W  
{ 1DE@N1l  
bFirst = false; @m~RtC-Q  
read_nPos(); !"Q}R p  
} M\oTZ@  
else F2 ~%zNe  
{ BByCMY  
nStartPos = new long[bean.getNSplitter()]; A5fwAB  
nEndPos = new long[bean.getNSplitter()]; 1zftrX~v!X  
} K=?VDN  
0:&ZnE}##  
<?h%k"5  
LZ U$  
} f[sF:f(zI  
4=Gph  
l&$$w!n0w  
public void run() I]nHbghcW  
{ pFsc}R/0/8  
//获得文件长度 VR5fqf|*  
//分割文件 ZH,4oF  
//实例FileSplitterFetch dQb.BOI)h  
//启动FileSplitterFetch线程 re &E{  
//等待子线程返回 >TjJA#  
try{ pS[KBQ"F  
if(bFirst) 2;`=P5V  
{ >dzsQ^Nj  
nFileLength = getFileSize(); }(XdB:C8  
if(nFileLength == -1) q<#>HjC  
{ =gh`JN6  
System.err.println("File Length is not known!"); jJZgK$5+  
} qTQ!jN  
else if(nFileLength == -2) _7T@5\b:;  
{ BV`-=wRC  
System.err.println("File is not access!"); 8Q{9>^  
} nqVZqX@oE  
else 6t'l(E +  
{ C1EtoOv K  
for(int i=0;i<nStartPos.length;i++) k0-G$|QgIp  
{ e`>{$t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q.4A(,  
} eP.Vd7ky  
for(int i=0;i<nEndPos.length-1;i++) NS)}6OI3~"  
{ U$dh1;  
nEndPos = nStartPos[i+1]; VdSv  
} ] b9-k  
nEndPos[nEndPos.length-1] = nFileLength; :!a2]-D}  
} W1B)]IHc  
} [+m?G4[  
}N0Qm[
R  
Cxod[$8  
//启动子线程 9+s.w25R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; S [h];eM  
for(int i=0;i<nStartPos.length;i++) ~9)"!  
{ NLPkh,T:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BBG3OAyg_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {U<xdG  
nStartPos,nEndPos,i); -<v~snq'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vx_o(wof  
fileSplitterFetch.start(); gBh;=vOD  
} ]lw|pvtd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mbnV[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I):!`R.,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7QKr_  
nEndPos = " + nFileLength); 6hZ@;Q=b  
// fileSplitterFetch[nPos.length-1].start(); P`s  
kr$b^"Ku  
@/ZF` :  
//等待子线程结束 2aJ
S{[  
//int count = 0; :1t~[-h^  
//是否结束while循环 wC `+  
boolean breakWhile = false; [aI]y=v  
B+^(ktZp@  
E*L iM5+I  
while(!bStop) 5JEbe   
{ FnJ?C&xK  
write_nPos(); ?4H i-  
Utility.sleep(500); h/B>S  
breakWhile = true; .9md~j:o^s  
7jnIv];i  
=
+t^f  
for(int i=0;i<nStartPos.length;i++) WTImRXK4  
{ s w39\urf  
if(!fileSplitterFetch.bDownOver) #2r}?hP/m  
{ 1x
,[6H  
breakWhile = false; ~"UV]Udn  
break; dnV[ P  
} P!"&%d  
} vjjSKP6B  
if(breakWhile) sdQkT#%y  
break; s21wxu:  
rvr-XGK36\  
ooUk O  
//count++; JH:0 L  
//if(count>4) hKzSgYxP=t  
// siteStop(); >yY'7Ey  
} x3PD1JUf  
J>u
 7,  
L#vI=GpL,r  
System.err.println("文件下载结束！"); < yC  
} ;j4?>3  
catch(Exception e){e.printStackTrace ();} gn3jy^5  
} J!:SPQ  
;|UF)QGa2  
#!)n {
h+  
//获得文件长度 (PfqRk1Y  
public long getFileSize() T0&f8  
{ z)HD`Ho  
int nFileLength = -1; ?.D3'qv  
try{ ei rzYt  
URL url = new URL(siteInfoBean.getSSiteURL()); c+
2FC@q{l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ( H6c{'&  
httpConnection.setRequestProperty("User-Agent","NetFox"); hUYd0qEbEt  
q7"7
U=W0  
^a#X9  
int responseCode=httpConnection.getResponseCode(); y.[Mnj  
if(responseCode>=400) qu|B4?Y/CR  
{ IEU^#=n  
processErrorCode(responseCode); Zfy
o-Wk  
return -2; //-2 represent access is error `3:.??7N  
} XP@1~$  
lGVEpCS}  
[o?*"c  
String sHeader; }Q";aU0^  
*6} N =Z  
1bH;!J  
for(int i=1;;i++) mW:!M!kk  
{ {RF-sqce  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G#?Sfn O0  
//Utility.log(in.readLine()); e#E2>Bj;  
sHeader=httpConnection.getHeaderFieldKey(i); i F+vl]  
if(sHeader!=null) @WI2hHD  
{ ca>Z7qT!  
if(sHeader.equals("Content-Length")) u?+Kkk
k  
{ 9k6r_G"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .j-IX1Sa  
break; eQ&ZX3*}  
} K3=3~uY  
} TYQwy*  
else ,dx3zBI  
break; "70WUx(\t  
} W>O~-2  
} 0)m(;>'70  
catch(IOException e){e.printStackTrace ();} $ >EY
hLBa  
catch(Exception e){e.printStackTrace ();} X_7UJ jFw"  
,%)6jYHRw  
0D&t!$Ibf  
Utility.log(nFileLength); g]c6&Y,#  
[B|MlrZ  
+gLPhX:`  
return nFileLength; z-b*D}&  
} zA1lca0HK  
w.0qp)}  
|Z*J/v'@p  
//保存下载信息（文件指针位置） =|YxDas  
private void write_nPos() ?!`=X>5  
{ DuOG {
 
try{ `3hSLR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TEaJG9RU>v  
output.writeInt(nStartPos.length); +*hm-lv?  
for(int i=0;i<nStartPos.length;i++) YWxc-fPZ  
{ kJ Mf  
// output.writeLong(nPos); g2T -TG'd  
output.writeLong(fileSplitterFetch.nStartPos); k0Uyf~p~  
output.writeLong(fileSplitterFetch.nEndPos); dtcIC0:[  
} <Ce2r"U1e  
output.close(); !OuWPH. :  
} b%S62(qP  
catch(IOException e){e.printStackTrace ();} 4-[J@  
catch(Exception e){e.printStackTrace ();} |\g5+fv9  
} G3{=@Z1  
pe{;~-|6  
*7wAkljP  
//读取保存的下载信息（文件指针位置） :"!9_p(,,  
private void read_nPos() &[;HYgp  
{ as>L[jyG/  
try{ U8G%YGMG.4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z%n(O(^L  
int nCount = input.readInt(); Rh>}rGvCUN  
nStartPos = new long[nCount]; qvv2O1c"A  
nEndPos = new long[nCount]; 4~N[%>zJ  
for(int i=0;i<nStartPos.length;i++) ,-OCc!7K  
{ J:kmqk!  
nStartPos = input.readLong(); ($~RoQ=0S  
nEndPos = input.readLong(); e@ \p0(  
} 7ek&[SJ>,/  
input.close(); u3o#{~E/#  
} L^{|uP15N
 
catch(IOException e){e.printStackTrace ();} +a*^{l}AST  
catch(Exception e){e.printStackTrace ();} A+UU~?3y  
}
+|
ycvHd  
,yTjU{<"  
c~v~2DM  
private void processErrorCode(int nErrorCode) (~J^3O]Fo  
{ %:2+ o'  
System.err.println("Error Code : " + nErrorCode); ~jb"5CX  
} bl'z<S, '  
EMc;^ d  
DzheoA-+L'  
//停止文件下载 gy;+_'.j  
public void siteStop() ;-Jb1"5  
{ c?%(DpE  
bStop = true; :(H>2xS,s  
for(int i=0;i<nStartPos.length;i++) 5
j-]EJb  
fileSplitterFetch.splitterStop(); Ii:>xuF&  
xrN &N_K#  
8dlw-Q'S  
} Wn>@9"  
} %G?;!Lz  
//负责部分文件的抓取 {Ions~cO)  
**FileSplitterFetch.java "{D|@
Bc  
*/ >pr=|$zk=  
package NetFox; bUY>st'  
,<Q~b%(
3  
.T*GN|@$!  
import java.io.*; ZKdeB3D  
import java.net.*; _A0mxq  
oY=q4D  
Ve/xnn]'  
public class FileSplitterFetch extends Thread { XhPe]P  
1lpw
Z"  
. ]8E7  
String sURL; //File URL wWXD\{Hk  
long nStartPos; //File Snippet Start Position A?*o0I  
long nEndPos; //File Snippet End Position
GTJ{h  
int nThreadID; //Thread's ID nJbbzQ,e  
boolean bDownOver = false; //Downing is over w%zRHf8C  
boolean bStop = false; //Stop identical cGwf!hA  
FileAccessI fileAccessI = null; //File Access interface ;2m<CSv!D  
p\Lq}tk<  
')N{wSM9Ft  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DE IB!n   
{ [0UGuj
  
this.sURL = sURL; y4Er@8I`  
this.nStartPos = nStart; ayBRWT0  
this.nEndPos = nEnd; %5*@l vy  
nThreadID = id; 4c+$%pq5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =\{\g7  
} 1w"8~Z:UXV  
gf+d!c(/  
Xq4|uuS-O  
public void run() <*EZ@XoN>  
{ s9oO%e<  
while(nStartPos < nEndPos && !bStop) #Z~C`n u  
{ C;~*pMAYe  
k6Cn"2q <  
6/ `.(fL1  
try{ Q# ?wXX47  
URL url = new URL(sURL); O3o: qly!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2ij# H ;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8Q)@  
String sProperty = "bytes="+nStartPos+"-"; x&A vUJ  
httpConnection.setRequestProperty("RANGE",sProperty); y]e>E  
Utility.log(sProperty); |3? 8)z\n  
4Tct  
nIfCF,
6,  
InputStream input = httpConnection.getInputStream(); ~svO*o Wa  
//logResponseHead(httpConnection); 9F;S+)H4  
Pgp {$ID  
{0YAzZ7  
byte[] b = new byte[1024]; Brd,Eg  
int nRead; M*pRv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /Y^8SO4  
{ }vt%R.u  
nStartPos += fileAccessI.write(b,0,nRead); tK%c@gGU9  
//if(nThreadID == 1) r(2R<A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qO`qJ/  
} Dmdy=&G  
uM(UO,X  
|Wj;QO$C  
Utility.log("Thread " + nThreadID + " is over!"); R,@g7p  
bDownOver = true; R UTnc  
//nPos = fileAccessI.write (b,0,nRead); EqM;LgE=  
} T,JA#Rk|1N  
catch(Exception e){e.printStackTrace ();} eR!G[Cw-  
} qS8B##x+=  
} D!TZI  
sY;lt.b  
#^mqQRpgq  
//打印回应的头信息 KhM.T
c  
public void logResponseHead(HttpURLConnection con) eK`PxoTI-I  
{ msk/p>{O  
for(int i=1;;i++) keqcV23k  
{ %"Db?  
String header=con.getHeaderFieldKey(i); Qu~*46?0  
if(header!=null) E(L<L1:"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SQ#7PKH  
Utility.log(header+" : "+con.getHeaderField(header)); ,-rB=|w  
else !E&MBAKy  
break; Rf[V)x  
} U=!@Db5k~  
} ^b53}f8H  
OV5e#AOy)  
if~rp-\P  
public void splitterStop() ]
h~o],:  
{ g#W_S?  
bStop = true; 30 7fBa  
} |f NMs  
C+l?k2  
<TjBd1  
} %2yAvG
a1  
 Tb#
  
$A?}a  
/* GNghB(  
**FileAccess.java *bZ\@Qm  
*//文件访问(定位，写) 'TX M{RGw  
package NetFox; EUwQIA2c8N  
import java.io.*; _pSIJ3O  
B| Q6!  
|s`Kd-'|q  
public class FileAccessI implements Serializable{ ~hD{coVTI  
l10-XU02  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $-w5o`e  
RandomAccessFile oSavedFile; k5X b}@
  
long nPos; vPsq<l}  
K\X: G-C9  
9cOx@c+/  
public FileAccessI() throws IOException l"L+e!B~  
{ ITn;m  
this("",0); ~R{8.!: >  
} k5s?lWH  
F '#^`G9  
xOM_R2Md  
public FileAccessI(String sName,long nPos) throws IOException `]hCUaV   
{ `5<1EGJsD  
oSavedFile = new RandomAccessFile(sName,"rw"); Y^5"qd|`  
this.nPos = nPos; u
Tw|Q{f  
oSavedFile.seek(nPos); Yhk6Uog{4  
} tnL."^%A2I  
P#F_>GB  
?.j,Bq5At  
public synchronized int write(byte[] b,int nStart,int nLen) c85O_J  
{ .m!s". ?[  
int n = -1; E- KK  
try{ H8<m9zDvl  
oSavedFile.write(b,nStart,nLen); 4[xA- \  
n = nLen; Fu mn9  
} HIrEv  
catch(IOException e) }JH`'&3  
{ sM0c#YK?  
e.printStackTrace (); N[]U%9[=2F  
} L-MiaKcL  
W'd/dKUx  
R;.d/U|av  
return n; Jtpa@!M  
} *seu&  
`TAcZl=8  
=;g=GcVK  
} tw]/,>\G  
~X[S<Gi#  
]|;7R^o3|  
/* "zXGp7Q'#  
**SiteInfoBean.java m^5s>hUl  
*/ 2h5tBEOX.s  
package NetFox; BjwMb&a;  
l~CZW*/  
::0aY;D2  
public class SiteInfoBean { hzW{_Q.|?  
HqB|SWyK  
Ko@zk<~"[  
private String sSiteURL; //Site's URL HUK"OH  
private String sFilePath; //Saved File's Path {WIY8B'c  
private String sFileName; //Saved File's Name n#)PvV~  
private int nSplitter; //Count of Splited Downloading File qjJ{+Rz2  
`D4oAx d9  
?VU
gwP_=  
public SiteInfoBean() 0T1HQ  
{//nSplitter的缺省值为5 #aj|vox}  
//default value of nSplitter is 5 /*AJ+K._  
this("","","",5); bkxk i@t  
} oo;;y,`8py  
2%`^(\y  
sg+ZQDF{x  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  {VS''Lv  
{ pCz@(:0  
sSiteURL= sURL; ^).WW  
sFilePath = sPath; w:ORmR.p  
sFileName = sName; 1 ,#{X3  
this.nSplitter = nSpiltter; M' a&  
,}eRnl
\  
F_ ,L2J  
} aJEbAs}  
e$ThSh\+(  
(y-x01H  
public String getSSiteURL() x:!C(Ep)  
{ aQ32p4C  
return sSiteURL; XRClBTKF  
} ?BWHr(J  
(45NZBs  
I{`KKui<M  
public void setSSiteURL(String value) 5%2ef{T[  
{ fR+Ov8PCq  
sSiteURL = value; X_vI0YX9  
} +A]&AkTw  

):/<H  
} l:mN  
public String getSFilePath() "[%;B0J  
{ u5u0*c  
return sFilePath; ^Nd|+}  
} LFk5rv'sM0  
E9L!O.Q  
?&whE!  
public void setSFilePath(String value) wJapGc!   
{ K[iY{  
sFilePath = value; [_g#x(=  
} ,Hik(22  
?)A]q' O  
G=r(SJq  
public String getSFileName() 0C7thl{Dms  
{ M!xm1-,[  
return sFileName; 5@w'_#!)  
} U6/m_`nc  
"'Q"(S  
N}8HK^n*  
public void setSFileName(String value) "a
y,
Lr  
{ q;1VF;<"vH  
sFileName = value; ]>VJ--fH  
} -(4E  
*3w/`R<\  
*tq|x[<  
public int getNSplitter() SXHru Z  
{ s8f3i\1  
return nSplitter; X]+(c_i:hC  
} f^[{k {t  
[#STR=_f  
g9FVb7In_  
public void setNSplitter(int nCount) 9sfB+]}h  
{ 'gk81@|  
nSplitter = nCount; @w#gRQCl  
} + e5  
} *6sJ*lh  
;EE&~&*w  
HggR=>s  
/* t[f9Z  
**Utility.java v)C:E9!|  
*/ j &0fC!k  
package NetFox; m>Z\ rqOK  
ig.6[5a\  
XoH[MJC  
public class Utility { <QkN}+B=  
6'No4[F 4n  
RB% fA%d  
public Utility() HYI1 o/}  
{ {g!exbVf  
-NflaV~  
o$HJg  
} v'bd.eqw  
)/+eLRN5G  
//线程睡眠 vS J<  
public static void sleep(int nSecond) giSG 6'WA  
{ }TX'
Z?Lq  
try{ +SuUI-.  
Thread.sleep(nSecond); Mc$v~|i6  
} ,Zcx3C:#  
catch(Exception e) $5Y^fwIK  
{ _OknP2E  
e.printStackTrace (); q/w6sQx$  
} RZ
/+K=  
} Y9H *S*n  
o+)LcoPu  
//日志 |q!2i  
public static void log(String sMsg) )q]j?Z.  
{ 8|jX ~f  
System.err.println(sMsg); #Zavdkw=d  
} |H+k?C-w  
Y%?!AmER  
!7NzW7j  
public static void log(int sMsg) 8#Z\}gGz  
{ ukDH@/  
System.err.println(sMsg); <>*''^  
} _9O }d  
} sm&rR=b  
RY/ Z~]  
#:\+7mCF  
/* .IAHy)li"  
**TestMethod.java *}iT6OJ  
*/ ubCJZ"!  
package NetFox; 7quwc'!  
knK=ENf;e  
_8b>r1$  
public class TestMethod { f?<M3P  
OB i!fLa  
E~g}DKs_5  
public TestMethod() _467~5JkU  
{ ///xx/weblogic60b2_win.exe \=G Xe.}4d  
try{ ^nm!NL{z^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AO7qs:+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0!'M#'m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o(SJuZC/U  
fileFetch.start(); W%XS0k}x  
} #/v_h6$  
catch(Exception e){e.printStackTrace ();} .id
l@%  
+VW]
%6+  
&fy8,}  
} NizJq*V>  
dSOn\+  
<C`eZ}Qqv  
public static void main(String[] args) >E,L"&_j  
{ >]|^Ux,WZ  
new TestMethod(); +4p;4/=  
} Pk]9.e1_  
} .&Gtw _  
点击下载更多相关资料