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http断点续传简单实现(java)

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/* .pN`;*7`  
**SiteFileFetch.java ?q; Fp  
*/ ReM=eS  
package NetFox; S5G6Rj@W  
import java.io.*; ^xij{W`|  
import java.net.*; DjN|Wr)*  
;K!]4tfJ  
(fCXxyZrr  
public class SiteFileFetch extends Thread { mo[Zb0>  
B, TB3 {  
WXmn1^"kK}  
SiteInfoBean siteInfoBean = null; //文件信息Bean vfq%H(  
long[] nStartPos; //开始位置 ds?v'|  
long[] nEndPos; //结束位置 lJE93rXU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {a4z2"\A  
long nFileLength; //文件长度 )0Me?BRp  
boolean bFirst = true; //是否第一次取文件 \ aHVs  
boolean bStop = false; //停止标志 20Z8HwQi  
File tmpFile; //文件下载的临时信息 b#K:_ac5  
DataOutputStream output; //输出到文件的输出流 qL6 |6-?  
Y@b.sMg{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) BI $   
public SiteFileFetch(SiteInfoBean bean) throws IOException m3mp/g.>  
{ rfNm&!K  
siteInfoBean = bean; :j]vf8ec  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l&?}hq^'Dn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }jVSlCF@t  
if(tmpFile.exists ()) /4 vG3  
{ (Nx;0"5IX  
bFirst = false; h\PHK C2  
read_nPos(); Ee3hG2d`  
} op6CA"w  
else *X, /7C   
{ @ ]/AjjLt  
nStartPos = new long[bean.getNSplitter()]; A9kzq_ 3  
nEndPos = new long[bean.getNSplitter()]; Zxbo^W[[  
} #1c_evH  
Vv8jEZ8  
V( -mD  
gMaN)ESqd4  
} ho0@ l  
Q)LM-ZJKQ  
hED=u/ql[  
public void run() <j5NFJ9  
{ S6AU[ASY.  
//获得文件长度 `~ * @q!  
//分割文件 aEWWFN  
//实例FileSplitterFetch 4( 1(e  
//启动FileSplitterFetch线程 w\DVzeW(  
//等待子线程返回 &9"-`-[e:  
try{ }b0; 0j  
if(bFirst) <_XWWT%  
{ 9\]^|?zQ`  
nFileLength = getFileSize(); %"af748!+D  
if(nFileLength == -1) IjR'Qou5  
{ L30$%G|  
System.err.println("File Length is not known!"); e}.^Tiwd]  
} k31I ysh  
else if(nFileLength == -2) 5<ux6,E1{  
{ j'BMAn ?  
System.err.println("File is not access!"); ##EYH1P]  
} rORZerM  
else d\ ~QBr?  
{ 2c:#O%d(  
for(int i=0;i<nStartPos.length;i++) =<NljOR4`  
{ k}0^&Quc4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R hvfC5Hq  
} "B8"_D&  
for(int i=0;i<nEndPos.length-1;i++) JGH60|  
{ HjGyj/78w  
nEndPos = nStartPos[i+1]; ]f_6 '|5 A  
} 9> g,  
nEndPos[nEndPos.length-1] = nFileLength; 'I /aboDB  
} stk9Ah  
} y;AL'vm9  
K%X^n>O7C  
D*YM[sN`  
//启动子线程 aN $}?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YI.w-K\  
for(int i=0;i<nStartPos.length;i++) i7utKj*57  
{ d R]Q$CJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o`q_wdy?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YcN!T"w J@  
nStartPos,nEndPos,i); <1.A=_ M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ulER1\W  
fileSplitterFetch.start(); "eWYv3z~-  
} & _g TD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _!?Hu/zo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rJ!{/3e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NM6Teu_  
nEndPos = " + nFileLength); P b]3&!a  
// fileSplitterFetch[nPos.length-1].start(); e4z1`YLsG  
+5&wOgx  
-M1YE  
//等待子线程结束 P7x =  
//int count = 0; H_ez'yy  
//是否结束while循环 ,+ #6Y_  
boolean breakWhile = false; }A:<%N  
0`I-2M4F*Q  
Iy.rqc/86  
while(!bStop) -p E(_  
{ { vN}<f`  
write_nPos(); YNBHBK4;  
Utility.sleep(500); ,s_T pq  
breakWhile = true; EgDQ+( -  
H=\!2XS  
WzI8_uM  
for(int i=0;i<nStartPos.length;i++) W{rt8^1  
{ &%_& 8DkG  
if(!fileSplitterFetch.bDownOver) .]9c/  
{ T1r3=Y4  
breakWhile = false; WMBm6?54  
break; `r_m+]  
} ( &frUQm  
}  =Mb1o[  
if(breakWhile) (}5S  
break; s9>(Jzcf9  
2*w:tT8+X  
~(@ E`s&{  
//count++; q9^  
//if(count>4) X2xuwA  
// siteStop(); R3!@?mcr  
} Y&^P"Dw  
1 `7<2w  
Vm|Y$ C  
System.err.println("文件下载结束!"); {" 4e+y  
} ad_`x  
catch(Exception e){e.printStackTrace ();} \6 93kQ  
} ee/&/Gt  
#%FN>v3e  
3w!c`;c%  
//获得文件长度 }=2;  
public long getFileSize() 7rC uu*M  
{ pMJ1v  
int nFileLength = -1; .y&QqxiE  
try{ rJo"fx  
URL url = new URL(siteInfoBean.getSSiteURL()); /2m?15c+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LsM7hLy  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6y5A"-  
5&f{1M6l>  
+~ #U7xgq/  
int responseCode=httpConnection.getResponseCode(); tWdhDt8$&  
if(responseCode>=400) Fbp{,V@F2  
{ w?,M}=vg  
processErrorCode(responseCode); Y=T'WNaL)0  
return -2; //-2 represent access is error ZK'-U,Y.H7  
} c0Dmq)HK?  
kpI{KISQu  
 P N*JR  
String sHeader; olW|$?  
q,2]5 '  
.Xdj(_&  
for(int i=1;;i++) _7D_72  
{ i0s6aAhgJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2nFy`|aA%  
//Utility.log(in.readLine()); 3<?XTv-  
sHeader=httpConnection.getHeaderFieldKey(i); G8IY#  
if(sHeader!=null) T'fcc6D5p  
{ oQ7]= |  
if(sHeader.equals("Content-Length")) 0gn@h/F2%  
{ /V?H4z[G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }N*>QR5K  
break; L@^~N$G&u  
} w~@-9<^K]v  
} (.Lrmf@hI7  
else {R^'=(YFy  
break; sgr=w+",Q  
} Sc]P<F7N]  
} 2Nj9U#A  
catch(IOException e){e.printStackTrace ();} 8:.nEo'  
catch(Exception e){e.printStackTrace ();} e2C<PGUUB  
Ft@Wyo`^  
#2tCV't  
Utility.log(nFileLength); ZE `lr+_Y  
XTDE53Js&  
60Z]M+8y8  
return nFileLength; w&BGJYI  
} n tP|\E  
b59{)u4F  
3qQUpm+  
//保存下载信息(文件指针位置) {$M;H+Foh  
private void write_nPos() ?_`0G/xl  
{ 1 11D3  
try{ $A}QY5`+~S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M"_FrIO  
output.writeInt(nStartPos.length); jFerYv&K~  
for(int i=0;i<nStartPos.length;i++) )nu~9km3  
{ <TNk?df7  
// output.writeLong(nPos); LihjGkj\g  
output.writeLong(fileSplitterFetch.nStartPos); (H?ZSeWx  
output.writeLong(fileSplitterFetch.nEndPos); Z7jX9e"L  
} gNx+>h`AF  
output.close(); uvA(Rn  
} _B,_4}  
catch(IOException e){e.printStackTrace ();} 9B)(>~q  
catch(Exception e){e.printStackTrace ();} @gSkROCdC)  
} Bfd-:`Jk  
X;!D};;M  
xiyxr R;  
//读取保存的下载信息(文件指针位置) +[m8c){  
private void read_nPos() iQ^: ])m>  
{ <3hA!$o~  
try{ K<v:-TjQZ:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %q_Miu@  
int nCount = input.readInt(); 9YF$CXonE=  
nStartPos = new long[nCount]; Gowp <9 F  
nEndPos = new long[nCount]; MjaUdfx  
for(int i=0;i<nStartPos.length;i++) D*vm cSf  
{ |)W!jC&k  
nStartPos = input.readLong(); Ak~4|w-  
nEndPos = input.readLong(); ;T ZGC).6  
} `dJDucD  
input.close(); ["3df>!f  
} Poa?Ej  
catch(IOException e){e.printStackTrace ();} =z:U~D  
catch(Exception e){e.printStackTrace ();} P ,K\  
} NE"jh_m-  
AH.9A_dG  
xfSG~csoz  
private void processErrorCode(int nErrorCode) *rqm8z50a  
{ R#4 ^s  
System.err.println("Error Code : " + nErrorCode); 2r ];V'r  
} zL s^,x  
!;>(i e\  
{aN(d3c  
//停止文件下载 Fu8 7fVi/\  
public void siteStop() }gsO&g"8  
{ C4$/?,K(  
bStop = true; ]2+g&ox4'  
for(int i=0;i<nStartPos.length;i++) hbuZaxo<  
fileSplitterFetch.splitterStop(); r3I,11B  
4Y tk!oS`  
!W1eUY  
} GH'O! }  
} JZ`L%  
//负责部分文件的抓取 N_C_O$j  
**FileSplitterFetch.java xKp0r1}  
*/ |0{ i9 .=  
package NetFox; n_$yV:MuT!  
6CNS%\A  
0^]t"z5f0  
import java.io.*; w1B<0'#  
import java.net.*; ^i<}]c_|f  
;mO,3dV  
L(WOet('  
public class FileSplitterFetch extends Thread { p27p~b&  
|*Ot/TvG  
\Tq "mw9P  
String sURL; //File URL kqB\xlS7k  
long nStartPos; //File Snippet Start Position "@/ba!L+  
long nEndPos; //File Snippet End Position ]Sta]}VQ  
int nThreadID; //Thread's ID Bt>}LLBS2  
boolean bDownOver = false; //Downing is over DY><qk  
boolean bStop = false; //Stop identical &]nd!N  
FileAccessI fileAccessI = null; //File Access interface oA3d^%(c  
|}qjqtZ  
 a@|.;#FF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1<uwU(  
{ tE!'dpG5)  
this.sURL = sURL; Mn"/#tXL-  
this.nStartPos = nStart; Riql,g/  
this.nEndPos = nEnd; h3J*1  
nThreadID = id; |vy]8?Ak  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Tkrx7C s(  
} !C7<sZ`C  
-,>:DUN2  
rrQ0qg  
public void run() \ j]~>9  
{ $T*KaX\{B  
while(nStartPos < nEndPos && !bStop) E:Y:X~vy  
{ Lr M}?9'  
onzA7Gre  
q[boWW  
try{ ZA.fa0n  
URL url = new URL(sURL); ",ad7Y7i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yQS04Bl]  
httpConnection.setRequestProperty("User-Agent","NetFox"); }'jV/  
String sProperty = "bytes="+nStartPos+"-"; Kcn\g.  
httpConnection.setRequestProperty("RANGE",sProperty);  EW5]!%  
Utility.log(sProperty); v,\93mNp[  
SY6r 8RK  
J%4HNW*p  
InputStream input = httpConnection.getInputStream(); K%<GU1]-]  
//logResponseHead(httpConnection); d2ofxfpg+  
/:6Q.onmLn  
tG 7+7Z =  
byte[] b = new byte[1024]; zZYHc?Z  
int nRead; |B1Af  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !?r/ 4  
{ 3ExVZu$  
nStartPos += fileAccessI.write(b,0,nRead); /$OIlu  
//if(nThreadID == 1) ^4hc+sh0D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,'-?:`hP'  
} ,%='>A  
aa=b<Cd  
!@yQK<0  
Utility.log("Thread " + nThreadID + " is over!"); 4H7Oh*P\j  
bDownOver = true; gCwt0)  
//nPos = fileAccessI.write (b,0,nRead); LO>8 j:  
} !>|`ly$6  
catch(Exception e){e.printStackTrace ();} cX"G7Bh  
} 3qcpf:  
} q+J0}y{#8)  
_U=S]2 Q W  
'X ~Ab  
//打印回应的头信息 2e\Kw+(>{  
public void logResponseHead(HttpURLConnection con)  f }-v  
{ "sIN86pCs  
for(int i=1;;i++) ypT9 8  
{ &O{t^D)F  
String header=con.getHeaderFieldKey(i); jhcuK:`L  
if(header!=null) h~.V[o7=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #[(0tc/  
Utility.log(header+" : "+con.getHeaderField(header)); #J3zTG(:@  
else Ris-tdg  
break; c.6QhE  
} ,|QU] E @  
} Pd& ,G$l  
/]l f>\x1  
s|p(KWo2U  
public void splitterStop() Wlxk  
{ 5YLho2h38!  
bStop = true; xx}'l:}2 ]  
} 'T{pdEn8u  
Q}ZBr^*]1e  
tJG (*   
} k#-[ M.i  
p|;o5j{  
SOYDp;j  
/* ep`/:iYW  
**FileAccess.java @s?oJpo  
*//文件访问(定位,写) {!tOI  
package NetFox; zlN+edgY#,  
import java.io.*; fX$6;Ae  
b`?M9f5  
t3M0La&  
public class FileAccessI implements Serializable{ KD9Ca $-  
B4 <_"0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OT"lP(,  
RandomAccessFile oSavedFile; ] : Wb1  
long nPos; R =QM;  
H;X~<WN&AW  
G)K9la<p  
public FileAccessI() throws IOException !zl/0o  
{ "9.6\Y\*  
this("",0); ~v,!n/('  
} hXBqz9  
@)06\ h  
Q,O]x#  
public FileAccessI(String sName,long nPos) throws IOException <6gU2@1  
{ M`q#,Y?3^I  
oSavedFile = new RandomAccessFile(sName,"rw"); J~:kuf21  
this.nPos = nPos; 2%*|fF}I  
oSavedFile.seek(nPos); :nTkg[49pJ  
} )8\Z=uC  
Vc{/o=1u  
MEDskvBG  
public synchronized int write(byte[] b,int nStart,int nLen) /}[zA@  
{ p$&_fzb  
int n = -1; oF` -cyj"  
try{  8APTk  
oSavedFile.write(b,nStart,nLen); Q&tFv;1w6  
n = nLen; baA HP "  
} mn,=V[f  
catch(IOException e) #`2GAM];7  
{ 7Ljs4>%l9j  
e.printStackTrace (); chMt5L+5  
} 69[w/\  
`z5v}T  
 #=>kw^5  
return n; ye9QTK6$,  
} A/ r;;S)%2  
F&-5&'6G+  
%_cg|yy  
} CA'hvXb.  
ZD iW72&Q  
%pQdq[J={  
/* V:$[~)k8  
**SiteInfoBean.java AJdlqbd'+  
*/ ^S>!kt7io  
package NetFox; eo-XqiJ,]  
u_$6LEp-  
zkw0jX~  
public class SiteInfoBean { tVK?VNW  
!hpTyO+%  
c|8KT  
private String sSiteURL; //Site's URL P1vF{e  
private String sFilePath; //Saved File's Path k B$lkl\C  
private String sFileName; //Saved File's Name WllCcD1  
private int nSplitter; //Count of Splited Downloading File Zm?G'06  
.f[\G*   
h?M'7Lti  
public SiteInfoBean() :z}~U3,JE  
{//nSplitter的缺省值为5 K .c6Rg  
//default value of nSplitter is 5 Fvcq^uZ  
this("","","",5); o%QhV6(F  
} ,5%aP%  
V1AEjh  
4{1c7g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GZ-n! ^  
{ aa'0EU:  
sSiteURL= sURL; (*c`<|)  
sFilePath = sPath; -#:Y+"'  
sFileName = sName; !^Qb[ev  
this.nSplitter = nSpiltter; u:p:*u_^I  
+U c&%Px  
\ltErd-  
} D z]}@Z*jK  
C[HE4xF6  
VbY>l' rY  
public String getSSiteURL() (W{rv6cq  
{ j8F~j?%!  
return sSiteURL; u/K)y:ZZ  
} BBZ)H6TzL  
:$u{  
F\YcSDM  
public void setSSiteURL(String value) cPa 0n4  
{ ACMpm~C8Gu  
sSiteURL = value; 8O}A/*1FJ  
} &)/H?S;yN  
j/; @P  
pU\xzLD  
public String getSFilePath() '8((;N|I^  
{ }*{\)7g  
return sFilePath; UeC%Wa<[  
} P+D|_3j  
#z1ch,*3;  
jn#N7%{Mk  
public void setSFilePath(String value)  G> 5=`  
{ )PanJHtU  
sFilePath = value; 8EVF<@{]  
} }(hYG"5  
6H. L!tUI  
Jh/M}%@|  
public String getSFileName() D q_{O  
{ 4jue_jsle  
return sFileName; e`gGzyM  
} Q?I"J$]&L  
ADJ5ZD<Q  
dk, I?c &  
public void setSFileName(String value) UO7a}Tz<  
{ Iu)(Huv  
sFileName = value; =QO1FO  
} 2*UE&Gp  
9-e[S3ziM  
(J?}eb;>n  
public int getNSplitter() IQIb\OUo!v  
{ xaq=?3QOH  
return nSplitter; .w*{=x0k  
} JJZXSBAOU  
9  lazo  
=6q*w^ET  
public void setNSplitter(int nCount) >8{`q!=|~  
{ XiZ Zo  
nSplitter = nCount; `'tw5}  
} D;#Yn M3  
} ]$`s}BN  
{D_4~heF  
* y"GgI  
/* Ar{=gENn  
**Utility.java vNwSZ{JBd  
*/ ;@ !d!&  
package NetFox; /Vj byRwV  
)Q pP1[  
:Y)kKq d  
public class Utility { e7j]BzGvl  
L)//- k9  
+#*z"a`  
public Utility() :J)l C =  
{ ,Elga}7u  
DF&jZ[##  
dXcMysRc%&  
} 3B_} :  
4Hd@U&E  
//线程睡眠 2|_Jup  
public static void sleep(int nSecond) T`2fPxM:cZ  
{ PXQ9P<m  
try{ uB)6\fkTB  
Thread.sleep(nSecond); <raqp Oo&  
} y<LwrrJ>  
catch(Exception e) bz,cfc;?$  
{ }_D5, k  
e.printStackTrace (); Iy 8E$B;  
} )PZ}^Fa  
} 3U.B[7fOM  
jKi*3-&  
//日志 T4, Zc  
public static void log(String sMsg)  ,IvnNnl2  
{ B7jlJqV  
System.err.println(sMsg); oG_'<5Bv>  
} $@f3=NJ4k  
rp[oH=&  
UDi3dH=  
public static void log(int sMsg) rM?Dp2  
{ m$UT4,Ol  
System.err.println(sMsg); Q Fqv,B\<  
} })u}PQ  
} es(LE/`e  
";Xbr;N  
0FR%<u  
/* ).`a-Pv  
**TestMethod.java t 6IaRD  
*/ zinl.8Uk  
package NetFox; *9:6t6x  
tMk>Bx9[  
gkn/E}K#  
public class TestMethod { bb_jD^  
OcS`Fxs  
6V?&hq&t  
public TestMethod() |JQP7z6j]  
{ ///xx/weblogic60b2_win.exe hADb]O  
try{ w`!foPE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w 4gZ:fR=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5J#g JFA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nv[Sb%/  
fileFetch.start(); ,* vnt6C*  
} s3RyLT  
catch(Exception e){e.printStackTrace ();} '\mZ7.Jj  
3#ZKuGg=  
{3uSg)  
} Wjk;"_"gd  
!P^$g R  
$u.T1v  
public static void main(String[] args) oK1[_ko|  
{ i|noYo_Ah\  
new TestMethod(); 9i[2z:4HJ  
}  /lok3J:  
} Gqc6).tn  
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