http断点续传简单实现（java)

/* 9 f$S4O5  
**SiteFileFetch.java x}o]R  
*/ 3yg22y&l  
package NetFox; O92a*)  
import java.io.*; <{!^  
import java.net.*; o8B_;4uB  
7xz~%xC.  
9QE|
p  
public class SiteFileFetch extends Thread { #vh1QV!Ho  
2c:H0O 0o  
Dlz||==  
SiteInfoBean siteInfoBean = null; //文件信息Bean :aHD'K  
long[] nStartPos; //开始位置 6QS[mWU  
long[] nEndPos; //结束位置 !9|)v7}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DE
"KbA0}  
long nFileLength; //文件长度 D>"U0*h
 
boolean bFirst = true; //是否第一次取文件 *I,3,zO  
boolean bStop = false; //停止标志 8&snLOU -Q  
File tmpFile; //文件下载的临时信息 pgT XyAP{  
DataOutputStream output; //输出到文件的输出流 U7O]g'BP  
6&V4W"k  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \;AW/&Ea  
public SiteFileFetch(SiteInfoBean bean) throws IOException B198_T!  
{ xHEkmL`)4  
siteInfoBean = bean; F%QZe*m[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p_h)|*W{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +9Z RCmV  
if(tmpFile.exists ()) R7aS{8nn  
{ "j|}-a  
bFirst = false; b(&~f@%|  
read_nPos(); +LddW0h+=8  
} #:Z"V8n'  
else K^z-G=|N  
{ qT]Bl+h2  
nStartPos = new long[bean.getNSplitter()]; iw1((&^)"  
nEndPos = new long[bean.getNSplitter()]; o%#Z  
} K0B J  
N}{CL(xi  
_YF~D
U  
^pz3L'4n  
} T8Sgu6:*R  
Q]X0O10  
48,Aq*JFw  
public void run() SPKen}g  
{ ^$3 ~;/|  
//获得文件长度 ;:xOW$  
//分割文件 Y ON@G5^  
//实例FileSplitterFetch )
Y':
u_Lo  
//启动FileSplitterFetch线程 ]P/eg$u'I  
//等待子线程返回 xh[4d  
try{ 0[6llcuj  
if(bFirst) Fs_,RXW"  
{ 7kpCBLM(}  
nFileLength = getFileSize(); *8k`m)h26  
if(nFileLength == -1) fM8kS  
{ BcV;EEi  
System.err.println("File Length is not known!"); a(CZGIB  
} p'{ `Uvr  
else if(nFileLength == -2) $t5 0<1  
{ G3QB Rh{  
System.err.println("File is not access!"); Q"c!%`\  
}
y@g{:/cmO  
else g;en_~g3j  
{ K]dqK'  
for(int i=0;i<nStartPos.length;i++) kfb+OE:7  
{ 0^44${bA  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3}O.B r|  
} 8OC5L1  
for(int i=0;i<nEndPos.length-1;i++) ;aYPv8s~,:  
{ &8t?OpB =h  
nEndPos = nStartPos[i+1]; o:C:obiQbu  
} cn ,zUG!-h  
nEndPos[nEndPos.length-1] = nFileLength; =DT
n9}u  
} r$ue1bH}|  
} SxXh N  
X70vDoW  
~h-G  
//启动子线程 =0xuH>WY}w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Avw"[~
Xd  
for(int i=0;i<nStartPos.length;i++) 9[5NnRv$P  
{ Ne/jvWWN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?!(/;RU1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W.p->,N  
nStartPos,nEndPos,i); G\h8j*o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QQ@, v@j5  
fileSplitterFetch.start(); G}i\UXFE  
} , 6\i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >VP\@xt(R[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o*/\oVOq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l ,)l"6OV  
nEndPos = " + nFileLength); g92M\5 x9  
// fileSplitterFetch[nPos.length-1].start(); wbI(o4rXE  
| (P%<  
P,AS`=z  
//等待子线程结束 9\
TvX!)h  
//int count = 0; LXIlrZ9D5  
//是否结束while循环 `g%]z@'+?  
boolean breakWhile = false; !$h%$se  
18w[T=7)  
y5?T`ts,#  
while(!bStop) Cq1t[a  
{ #Q6wv/"Ub  
write_nPos(); S6}_Z  
Utility.sleep(500); S}e*~^1J  
breakWhile = true; &nn!{S^  
/6F 1=O(c>  
@FkNT~OZ  
for(int i=0;i<nStartPos.length;i++) If6wkY6sR  
{ YkPz ~;  
if(!fileSplitterFetch.bDownOver) Y'/`?CK  
{ x[nv+n ,  
breakWhile = false; [.<nt:  
break; $Z10Zf=  
} .&7=ZY>E  
} U._ U!U  
if(breakWhile) M@!Gk  
break; P,h@F+OZN  
_ %&"4bm.  
,Z_nV+l_  
//count++; |NtT-T)7  
//if(count>4) 8!>uC&bE8  
// siteStop(); DS>s_3V  
} M;zRf3S  
: ` F>B  
eHv~?b5l  
System.err.println("文件下载结束！"); KGi@H
%NN  
} @babgP,  
catch(Exception e){e.printStackTrace ();} 9 )B>|#\  
} g^)>-$=  
lGG
1d  
w,8 M  
//获得文件长度 ] >ipC,v  
public long getFileSize() sLbz@54  
{ toTAWT
D  
int nFileLength = -1; /G[y 24 Q  
try{ pRc(>P3;  
URL url = new URL(siteInfoBean.getSSiteURL()); WbH/K]/1)h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !nV
X .m9  
httpConnection.setRequestProperty("User-Agent","NetFox"); IvIBf2D;Q  
NL&g/4A[a  
&%u,b~cL?  
int responseCode=httpConnection.getResponseCode(); |BH, H  
if(responseCode>=400) k`)LO`))  
{ C==tJog[  
processErrorCode(responseCode); 3Un/-4uL  
return -2; //-2 represent access is error
F]yclXf('  
} c'`7p/l.  
|nry^zb  
n4."}DO  
String sHeader; l$m^{6IYc  
Bo%M-Gmu  
BqZLqGOKu  
for(int i=1;;i++) w#PaN83+  
{ WS(@KN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); NBMY1Xgj  
//Utility.log(in.readLine()); D4#,9?us  
sHeader=httpConnection.getHeaderFieldKey(i); &KR@2~vE  
if(sHeader!=null) 3pDZ}{ZZU  
{ [9(B;;R@  
if(sHeader.equals("Content-Length")) L$jyeFB5  
{ ;SC|VcbyH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sef!hS06  
break; 't)j  
} fE7WLV2
I>  
} g1zqh,  
else Tg:NeAN7(  
break; bMSF-lQ  
} ui 2RTAb  
} mz\m^g3  
catch(IOException e){e.printStackTrace ();} Q ;k_q3  
catch(Exception e){e.printStackTrace ();} +#B%YK|LR  
A5H[g`&  
3J,/bgL5  
Utility.log(nFileLength); *c3o&-ke9  
9oq(5BG,  
:cynZab  
return nFileLength; '!1lK  
} p$9N}}/c  
R*yB);p  
K4RjGSaF  
//保存下载信息（文件指针位置） ;( 2uQ#Y  
private void write_nPos() V;:A&  
{ b/5~
VY*T  
try{ tQl=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nQ~q-=,L  
output.writeInt(nStartPos.length); uwQ4RYz  
for(int i=0;i<nStartPos.length;i++)
,MvvW{EY  
{ uo%O\}#u9  
// output.writeLong(nPos); \pPq]k  
output.writeLong(fileSplitterFetch.nStartPos); T2(+
HI2  
output.writeLong(fileSplitterFetch.nEndPos); ]iNSa{G  
} IS=)J( 0  
output.close(); QM_~w\  
} H+ M~|Ju7  
catch(IOException e){e.printStackTrace ();} aPb!-o{  
catch(Exception e){e.printStackTrace ();} iTK1I0  
} "R30oA#m  
O-'T*M>  
u8,T>VNVw  
//读取保存的下载信息（文件指针位置） 5j}@Of1pd  
private void read_nPos() 3<`h/`ku  
{ XqwdJND  
try{ n&V(c&C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); dF?pEet?2  
int nCount = input.readInt(); @%fkW"y:  
nStartPos = new long[nCount]; <'vM+Lk  
nEndPos = new long[nCount]; \Fe5<G'v  
for(int i=0;i<nStartPos.length;i++) zO\"$8q*  
{ ^al SyJ`  
nStartPos = input.readLong(); >C&!# 3  
nEndPos = input.readLong(); ^a}{u$<  
} v0xi(Wu  
input.close(); TX+t   
} #UI`G3w<  
catch(IOException e){e.printStackTrace ();} }}xR?+4A  
catch(Exception e){e.printStackTrace ();} -OW$  
} oz0-'_  
:m~lgb<  
~g,QwaA[  
private void processErrorCode(int nErrorCode) _j2`#|oG  
{ @v'<~9vG  
System.err.println("Error Code : " + nErrorCode); %FRkvqV*  
} dW5z0VuB$/  
~G$OY9UC  
"l@~WE  
//停止文件下载 0y1t
%C075  
public void siteStop() vaU7tJ:  
{ +I~?8*  
bStop = true; 6x7=0}'  
for(int i=0;i<nStartPos.length;i++) u}h'v&"e,  
fileSplitterFetch.splitterStop(); x-QP+M`Pu  
\G"/Myi  
g ` {0I[  
} }9kq?  
} tO0+~Wm  
//负责部分文件的抓取 }hf*Jw  
**FileSplitterFetch.java G?g7G,|d  
*/ Z:OO|x  
package NetFox; KWYG\#S0]  
0qZ)$YKq  
g[n8N
{s  
import java.io.*; Lr~K3nb  
import java.net.*; ;K_B,@:'  
ditzl(L   
x?F{=\z
/o  
public class FileSplitterFetch extends Thread { 0CR;t`M@  
;|%r!!#-t  
d"cfSH;h  
String sURL; //File URL  (M
=Br  
long nStartPos; //File Snippet Start Position uXC?fMWp.  
long nEndPos; //File Snippet End Position O*PHo_&G  
int nThreadID; //Thread's ID ) jvkwC  
boolean bDownOver = false; //Downing is over zhe5i;M  
boolean bStop = false; //Stop identical t5qAH++axN  
FileAccessI fileAccessI = null; //File Access interface s [!SG`&  
j AE0$u~.  
W7 E-j+2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c%dy$mkqgK  
{ [4t KJ+v  
this.sURL = sURL; #(H_w4  
this.nStartPos = nStart; R}VL UL$  
this.nEndPos = nEnd; uj@<_|7  
nThreadID = id; w\ :b(I  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &|4Uo5qS=Z  
} R;yAqr29  
E6gEP0b  
2uTa}{/%  
public void run() ww2Qa-K  
{ bi[l,  
while(nStartPos < nEndPos && !bStop) +g[B &A!d+  
{ K_aN7?#.v`  
._3NqE;
 
rifxr4c[X>  
try{ `lhLIQ'j  
URL url = new URL(sURL); <j#EyGAV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YMd&+J`  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?Sqm`)\>4  
String sProperty = "bytes="+nStartPos+"-"; ["M>  
httpConnection.setRequestProperty("RANGE",sProperty); ("6W.i>  
Utility.log(sProperty); H-W)Tq_?-  
m0"\3@kB  
t;]egk  
InputStream input = httpConnection.getInputStream(); bM-Rj1#Lo  
//logResponseHead(httpConnection); :I('xVNPz  
12a #]E  
(`u!/  
byte[] b = new byte[1024]; B`aAvD`7  
int nRead; %},gE[N!J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o;mIu#u  
{ o0L#39`'g  
nStartPos += fileAccessI.write(b,0,nRead); sdWl5 "  
//if(nThreadID == 1) :ct+.#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j1<1D@UO  
} dWy1=UQfP  

Z]f2&  
x,dv~QU  
Utility.log("Thread " + nThreadID + " is over!"); 3c3Z"JV  
bDownOver = true; 3Y-v1.^j  
//nPos = fileAccessI.write (b,0,nRead); H~i],WD  
} E2IVR]C2^  
catch(Exception e){e.printStackTrace ();} q1Sm#_7  
} -#6*T,f0P(  
} )mdNvb[*n  
7 L\?  
`1@[uWl  
//打印回应的头信息 W<VHv"?V  
public void logResponseHead(HttpURLConnection con) BT3O_X`u  
{ @E2nF|N  
for(int i=1;;i++) ntV>m*^  
{ NO^t/(Z  
String header=con.getHeaderFieldKey(i); J"rwWIxO*  
if(header!=null) uN 62>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %ZyPK,("  
Utility.log(header+" : "+con.getHeaderField(header)); % eRwH >  
else 29^bMau)v  
break; 3L?a4,Q"k}  
} GuWBl$|+b  
} fm>K4\2  
]F;]<_  
2hJ3m+N^  
public void splitterStop() QtQ^"d65  
{ ssITe.,ny  
bStop = true; >` QX xTn  
} g{hA,-3  
[Z\1"m  
+3>/,w(x  
} x 5Dt5Yp"o  
{Ch"zuPX  
F |81i$R  
/* +c`C9RXk  
**FileAccess.java v6?\65w,|  
*//文件访问(定位，写) m1i+{((  
package NetFox; yQ{_\t1Wd  
import java.io.*; [9om"'  
X-#mv|3  
' u};z:t  
public class FileAccessI implements Serializable{ ?]D+H%3[$i  
o%PoSZZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YwWTv  
RandomAccessFile oSavedFile; }#*zjMOz  
long nPos; Z'dI!8(Nf  
r/sRXM:3cZ  
Ko|xEz=  
public FileAccessI() throws IOException AdOAh y2H  
{ h)
PB  
this("",0); o!r4 frP  
} OCO,-
(  
YCBML!
L  
rqe_zyc&  
public FileAccessI(String sName,long nPos) throws IOException 6XL9 qb~X  
{ >ha Ixs`
9  
oSavedFile = new RandomAccessFile(sName,"rw"); zMzf=~  
this.nPos = nPos; b%f2"e0g  
oSavedFile.seek(nPos); 1=5'R/k  
} zRo
Ex1  
x ETVtq  
GnrW{o  
public synchronized int write(byte[] b,int nStart,int nLen) zw0 r i6  
{ W#7-%oT  
int n = -1; ;:\,x  
try{ lEbR)B,  
oSavedFile.write(b,nStart,nLen); k,iV$,[TF  
n = nLen; Ox*T:5  
} 40d9/$uzh  
catch(IOException e) I u~aTgHX%  
{ Doc'7P  
e.printStackTrace (); 'A(-MTd%  
} \ Q8q9|g?]  
rn[}{1I33Q  
4i\aW:_'i  
return n; ^=Tu>{uD  
} h8= MVh(I  
K<  
_B7?C:8Q-  
}
YS
z$` 7i  
?CW^*So  
P}WhE  
/* X`v79`g_  
**SiteInfoBean.java Fl
A\Ad;v  
*/ l)PFzIz=V  
package NetFox; vua1iN1  
aco}pXz  
l^y?L4hg)  
public class SiteInfoBean { 6dR-HhF  
m>-^K  
u3i|}`  
private String sSiteURL; //Site's URL "ko?att~  
private String sFilePath; //Saved File's Path M3;v3 }z<-  
private String sFileName; //Saved File's Name ?]:EmP  
private int nSplitter; //Count of Splited Downloading File g yH7((#i  
sEJ;t0.LX  
- Zoo)  
public SiteInfoBean() y7IbE  
{//nSplitter的缺省值为5 (zro7gKked  
//default value of nSplitter is 5 ?r'TH/>  
this("","","",5); (VXx G/E3  
} ];{
l$-$$  
O$umu_  
v6DxxE2n  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )"c]FI[}  
{ c>WpOZ,  
sSiteURL= sURL; 'UXj\vJ3E  
sFilePath = sPath; -G<2R"Q#N  
sFileName = sName; )av'u.]%c  
this.nSplitter = nSpiltter; JU=\]E@8c  
C(1A8  
MHr0CYyb.  
} XG\a-dq[  
Vh.;p.!e  
OxHw1k  
public String getSSiteURL() 6=g]Y!o$  
{ {cyo0-9nv  
return sSiteURL; d,J<SG&L&  
} kq}eUY]  
fF9oYOh|  
E%2!C/+B  
public void setSSiteURL(String value) >]XaUQ-  
{ 71<PEawL  
sSiteURL = value; cH*/zNp  
} N4`
9TN7  
&(uF&-PwO4  
o )nT   
public String getSFilePath() !Nxn[^[?.  
{ @F(3*5c_Y  
return sFilePath; =y-!k)t  
} 9>[.=  
j#nO6\&o  
8T.5Mhx0jS  
public void setSFilePath(String value) #SihedWi  
{ R!V5-0%  
sFilePath = value; Uygw*+  
} w(e+o.:  
2) /k`Na  
9*TS90>a  
public String getSFileName() d0}%%T  
{ ^;CR0.4  
return sFileName; |p8"9jN@}c  
} DtJTnvG~B  
il>x!)?o  
nzE,F\k  
public void setSFileName(String value) v1
"g!%U6  
{ ej"o?
1l@  
sFileName = value; 8F`BJ6='  
} \{MrQ2jd  
w[,?-Xm  
gSv[4,hXd  
public int getNSplitter() EDgob^>  
{ 8W1K3[Jj<  
return nSplitter; .y;\puNq  
} 9OQ0Yc!3  
kP}hUrDX5  
.XLV:6  
public void setNSplitter(int nCount) 2*-ENW2  
{ S4{Mu(^xT  
nSplitter = nCount; /:Z~"Q*r  
} _8NEwwhc  
} ;1R?9JN"  
X
8,7_D$  
m_E[bDON  
/* ,3J`ftCV  
**Utility.java }4\!7]FVYX  
*/ \%-E"[!  
package NetFox; b5n]Gp  
].k+Nzf_  
$xUzFLh=`  
public class Utility { #A|D\IhF  
L)R[)$2(g  
z*dQIC  
public Utility() e0~sUVYf  
{ 1o;g1Z/  
n2jvXLJq  
r{_B:  
} [yYH>~SuwZ  
:Er^"9'A2  
//线程睡眠 :!+}XT7)/  
public static void sleep(int nSecond) u^aFj%}]L  
{ n,&/D  
try{ {XDY:`vZ}  
Thread.sleep(nSecond); ElEv(>G*  
} #LN5&i;s  
catch(Exception e) !sfXq"F  
{ 8z
."X$  
e.printStackTrace (); 7|+|\7l#  
} ,
TKs/-_?  
} V>FT~k_"  

d4y9AE@k  
//日志 FUyB
"-<  
public static void log(String sMsg) s.R-<Y3  
{ 68koQgI[^  
System.err.println(sMsg); !^
)wPmk  
} `?zg3GD_  
o[bE  
96"yNqBf  
public static void log(int sMsg) V9fGVDl;  
{ ;0w^ud  
System.err.println(sMsg); Q)LXL.0h  
} tb:,Uf>E  
} M('s|>\l  
?Y?gzD  
 (kWSK:l  
/* u0bfX,e2U  
**TestMethod.java ?Do^stq'4  
*/ c-4m8Kg?L  
package NetFox; _KB{J7bs<a  
V>b2b5QAH,  
}J ei$0x  
public class TestMethod { mQd4#LJ_  
*#&k+{a^2  
54q4CagFq  
public TestMethod() H&w:`JYDL3  
{ ///xx/weblogic60b2_win.exe w(76H^e  
try{ 
ID67?:%r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); NJ;"jQ-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8 uDerJ!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); EJf#f
 
fileFetch.start(); (C8 U   
} ;y>S7n>n:  
catch(Exception e){e.printStackTrace ();} Ds%9cp*6  
~Cjz29|gp  
"w}-?:# j  
} f4]N0  
"z rA``  
~bdv_|k  
public static void main(String[] args) {>8Pl2
J  
{ z%(Fo2)^  
new TestMethod(); &49u5&TiP  
} LHs-&  
} ,Bisu:v6FW  
点击下载更多相关资料