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http断点续传简单实现(java)

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/* A^q= :ofQ  
**SiteFileFetch.java V2g,JFp&  
*/ o+;=C@,'  
package NetFox; `!S5FE"-  
import java.io.*; bxyEn'vNvQ  
import java.net.*; !H{)L@f  
Wa #,>  
`~UCWK  
public class SiteFileFetch extends Thread { 8A"[n>931  
Kv:UQdnU[  
Q\z3YUk  
SiteInfoBean siteInfoBean = null; //文件信息Bean `]\4yTd  
long[] nStartPos; //开始位置 |w- tkkS  
long[] nEndPos; //结束位置 <4bv=++pS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LeO ))  
long nFileLength; //文件长度 ?Pw# !t  
boolean bFirst = true; //是否第一次取文件 c=I!?a"  
boolean bStop = false; //停止标志 SW (7!`  
File tmpFile; //文件下载的临时信息 K6KEdXM4  
DataOutputStream output; //输出到文件的输出流 &UP@Sr0D7  
:>nk63V (  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 8H./@~_ =  
public SiteFileFetch(SiteInfoBean bean) throws IOException +'>N]|Z  
{ 6T< ~mn  
siteInfoBean = bean; j8zh^q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j$T2ff6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 75K~ebRr  
if(tmpFile.exists ()) Bh:AY@k  
{ KD$P\(5#  
bFirst = false; }!0,(<EsV  
read_nPos(); (sS[F-2R7  
} H|0B*i@81  
else |O\(<n S  
{ 4en&EWUr  
nStartPos = new long[bean.getNSplitter()]; bVtboHlY  
nEndPos = new long[bean.getNSplitter()]; ^%M!!wlUH  
} zF;}b3oIo  
P0RM df  
\4K8*`$  
T=VVK6Lc:  
} ^*A/92!yF  
sa#=#0yg  
YM3oqS D  
public void run() }tft@,dIC  
{ jt"p Js'  
//获得文件长度 6]T02;b>/,  
//分割文件 mb0${n~fz  
//实例FileSplitterFetch uP|AP  
//启动FileSplitterFetch线程 oVoTnGNM6  
//等待子线程返回 :J(a;/~ip  
try{ g.DgJX&i  
if(bFirst) GuM-H $,  
{ /Ia=/Jj7N  
nFileLength = getFileSize(); ;TmwIZ  
if(nFileLength == -1) z9h`sY~  
{ `U2PlCf |  
System.err.println("File Length is not known!"); TUy*wp9  
} feNr!/  
else if(nFileLength == -2) x18ei@c  
{ i`2Q;Az_P6  
System.err.println("File is not access!"); DbPw) aCj  
} 8k_,Hni  
else 8C,?Ai<ro  
{ xhUQ.(S`r6  
for(int i=0;i<nStartPos.length;i++) GgA =EdJn  
{ b\=0[kBQw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'G-VhvM v  
} LE1&atq  
for(int i=0;i<nEndPos.length-1;i++) !G\1$"T$  
{ gQ?>%t]  
nEndPos = nStartPos[i+1]; .4_ ~ku  
} nn#A-x}~;b  
nEndPos[nEndPos.length-1] = nFileLength; He#+zE ;  
} Oq+C<}eg  
} $23="Jcl  
iY;)R|6  
gP/]05$e  
//启动子线程 ,Oxdqxu7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Aba6/  
for(int i=0;i<nStartPos.length;i++) kdxs{b"t  
{ ZR..>=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E8%O+x}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^4s#nf:}  
nStartPos,nEndPos,i); Dm 'Q&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3D<P [.bS  
fileSplitterFetch.start(); IH>+P]+3"3  
} )x( *T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AqN(htGvx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %#7M~RB[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LgBs<2  
nEndPos = " + nFileLength); ^gb2=gWZ<  
// fileSplitterFetch[nPos.length-1].start(); r\Man'h$  
<&H.pN1_  
0Fbq/63  
//等待子线程结束 vtL)  
//int count = 0; >St  
//是否结束while循环 dZnq 96<:|  
boolean breakWhile = false; vKaX,)P;?  
6GJ?rE E/  
S;|%'Sn|j9  
while(!bStop) T( ;BEyc?  
{ M.|hnGX N  
write_nPos(); #wC4$y<>  
Utility.sleep(500); |W#^L`!G  
breakWhile = true; xss D2*l  
?5/Sa  
!3HMGzt  
for(int i=0;i<nStartPos.length;i++) F'SOl*v(s5  
{ jq}5(*k  
if(!fileSplitterFetch.bDownOver) A;2?!i#f  
{ Nb B`6@r  
breakWhile = false; ~hM4({/QN  
break; J+z0,N[  
} snj+-'4T  
} \J1Jn~  
if(breakWhile) @x{;a9y  
break; hV=)T^Q  
^-=,q.[7  
B&.XGo)  
//count++; t%8*$"~X  
//if(count>4)  Gc SX5c  
// siteStop(); DoImWNLo  
} _-^ KqNyy  
noL<pkks~R  
r--"JO%2  
System.err.println("文件下载结束!"); 1}V_:~7  
} ZEApE+m  
catch(Exception e){e.printStackTrace ();} >nTGvLOq  
} iLS' 47  
:r#FI".qx  
gy*N)iv%  
//获得文件长度 %X#Wc:b  
public long getFileSize() L4Kkbt<x  
{ 501|Y6ptl  
int nFileLength = -1; [QL)6Xr  
try{ ]LP&v3  
URL url = new URL(siteInfoBean.getSSiteURL()); vH7"tz&RIp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f+gyJ#R`  
httpConnection.setRequestProperty("User-Agent","NetFox"); A u(Ngq  
"CLd_H*)c  
neOR/]  
int responseCode=httpConnection.getResponseCode(); BH%eu 7`t  
if(responseCode>=400) ]A!Gr(FHQ  
{ nDaQ1  
processErrorCode(responseCode); odj|" ZK  
return -2; //-2 represent access is error 4Jo:^JV  
} qY0GeE>N  
6'?Y]K  
P_i2yhpK  
String sHeader; Y+WOU._46I  
sFB; /*C  
j;<;?IW  
for(int i=1;;i++) a"hlPJlG  
{ tQUp1i{j\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PVV\@  
//Utility.log(in.readLine()); |QxDjL<&t4  
sHeader=httpConnection.getHeaderFieldKey(i); \!s0VEE  
if(sHeader!=null) \ Fc"Q@.u  
{ SRj|XCd  
if(sHeader.equals("Content-Length")) %.<w8ag  
{ w,JB`jS)/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V^.~m;ETu]  
break; n_?<q{GW  
} ly6?jVJ  
} wCc:HfmjJ  
else .qF@ }dO  
break; WvNX%se]3  
} [)9bR1wh  
} v)J6}H}e  
catch(IOException e){e.printStackTrace ();} 8a e]tX5$  
catch(Exception e){e.printStackTrace ();} sx(yG9  
-Z]?v3 9  
g4%x7#vz0  
Utility.log(nFileLength); TvMY\e  
y]M/oH  
'J]V"Z)  
return nFileLength; &|Z:8]'P  
} uVOOw&q_  
6}{2W<  
_vvnxG!x&  
//保存下载信息(文件指针位置) .ay K+6I  
private void write_nPos() }q27M  
{ WihOGdUS6  
try{ 3}n=od=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w.J2pvyB  
output.writeInt(nStartPos.length); JTl 37j  
for(int i=0;i<nStartPos.length;i++) Qe]@`Vg  
{ t'0r4&\  
// output.writeLong(nPos); o&gcFOM22  
output.writeLong(fileSplitterFetch.nStartPos); I+8m1 *  
output.writeLong(fileSplitterFetch.nEndPos); nN/v7^^  
} #.a4}ya19  
output.close(); HIi"zo=V  
} f{WJM>$:  
catch(IOException e){e.printStackTrace ();} 7f[nNng  
catch(Exception e){e.printStackTrace ();} 6"eGd"  
} "uqa~R{  
1wqCoDgkp  
k/!Vv#8  
//读取保存的下载信息(文件指针位置) xg\M9&J  
private void read_nPos() e +4p__TmZ  
{ 8~\Fpz|Og  
try{ m7^a4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `H ^Nc\P#  
int nCount = input.readInt(); :#I8Cf  
nStartPos = new long[nCount]; m-> chOu~|  
nEndPos = new long[nCount]; G:A ~nv9  
for(int i=0;i<nStartPos.length;i++) 9j$ OU@N 8  
{ fx%'7/+  
nStartPos = input.readLong(); c*MjBAq  
nEndPos = input.readLong(); !);}zW!  
} Pw hs`YGMF  
input.close(); ^=E4~22q  
} ?2_u/x  
catch(IOException e){e.printStackTrace ();} -!(3fO:  
catch(Exception e){e.printStackTrace ();} c{rX7+bN  
} w*#TS8 \  
/2Y Nu*v  
f+%J=Am  
private void processErrorCode(int nErrorCode) zZki9P   
{ +*!oZKm.  
System.err.println("Error Code : " + nErrorCode); <74q]C  
} :[|`&_D9J  
wC'KI8-  
-md2Z0^ Kc  
//停止文件下载 n*@^c$&P  
public void siteStop() +lO Y IQ  
{ Nd^9.6,JU  
bStop = true; Qj[4gN?}=  
for(int i=0;i<nStartPos.length;i++) I)_072^O  
fileSplitterFetch.splitterStop(); /PQg>Pa85  
!*?&V3!  
Nz*qz"T  
} =lr*zeHLC  
} Rj+}L ~"  
//负责部分文件的抓取 .y+>-[j?B  
**FileSplitterFetch.java $-M1<?5  
*/ zP rT0  
package NetFox; [)Xu60? Q  
:4]&R9J>o  
{BY`Wu:w  
import java.io.*; ~k|~Q\   
import java.net.*; 5(u7b  
(U/6~r'.L  
g0cCw2S  
public class FileSplitterFetch extends Thread { 57v[b-SK  
cS4e}\q,  
XRJ<1w:  
String sURL; //File URL j)'V_@  
long nStartPos; //File Snippet Start Position q+WOnTS  
long nEndPos; //File Snippet End Position [WY NA-O  
int nThreadID; //Thread's ID E I)Pfx"0  
boolean bDownOver = false; //Downing is over <*2.B~  
boolean bStop = false; //Stop identical gigDrf}  
FileAccessI fileAccessI = null; //File Access interface |cWW5\/  
P,_GTs3/G  
1nBE8 N  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &tLg}7?iB  
{ cV&(L]k>`  
this.sURL = sURL; 9n |H%AC  
this.nStartPos = nStart; j 7a;g7.  
this.nEndPos = nEnd; u9N?B* &{  
nThreadID = id; at6f(+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TnPdpynP  
} a!Z,~ V8  
Fm*n>^P@Y  
o=w& &B  
public void run() }P-9\*hlm  
{ xg. d)n  
while(nStartPos < nEndPos && !bStop) 2ZNTg@o  
{ L a0H  
H Tf7r-  
Ij@YOt  
try{ +%UXI$v  
URL url = new URL(sURL); QIBv}hgcy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9.#\GI ;  
httpConnection.setRequestProperty("User-Agent","NetFox");  W* `2lf  
String sProperty = "bytes="+nStartPos+"-"; fVb&=%e  
httpConnection.setRequestProperty("RANGE",sProperty); Yt0 l'B%[u  
Utility.log(sProperty); <3Co/.VQd  
L7q%u.nB1  
xI}]q%V  
InputStream input = httpConnection.getInputStream(); .~ZNlI {K  
//logResponseHead(httpConnection); #E{OOcM  
)q&uvfQ1(  
QOy+T6en  
byte[] b = new byte[1024]; S[X bb=n  
int nRead; D-E30b]e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s-o0N{b?#'  
{ jP@H$$-=wH  
nStartPos += fileAccessI.write(b,0,nRead); ,t*#o&+  
//if(nThreadID == 1) ;gK+AU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y;xVB" (  
} 4SY]Q[  
.QRQvtd.  
5s;HF |2x  
Utility.log("Thread " + nThreadID + " is over!"); 6yv*AmFh  
bDownOver = true; J@p[v3W  
//nPos = fileAccessI.write (b,0,nRead); xh_6@}D2J  
} i7mT<w>?  
catch(Exception e){e.printStackTrace ();} }`h)+Im=  
} ;}=v|Dr&I.  
} vZhN% DfY  
$-jj%x\}  
My,ki:V?g6  
//打印回应的头信息 qyp"q{k0  
public void logResponseHead(HttpURLConnection con) iW.8+?Xq&  
{ F>96]71 2  
for(int i=1;;i++) +>44'M^Z|(  
{ 6_^ u}me  
String header=con.getHeaderFieldKey(i); x AkM_<  
if(header!=null) |XLx6E2F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6EGh8H f  
Utility.log(header+" : "+con.getHeaderField(header)); [@uL)*o_#  
else j'X]bd'  
break; kNd[M =%  
} $X9-0-  
} z )a8 ^]`  
)0yY|E\  
7t0\}e  
public void splitterStop() CP]BSyim'  
{ -KCm#!  
bStop = true; q,PB; TT  
} ) e;)9~  
]lXTIej`dy  
UyEyk$6SU  
} Y \& 4`v'  
vz#rbBY*;  
P%ev8]2  
/* IT'~.!o7/  
**FileAccess.java N$6Rg1  
*//文件访问(定位,写) *G.6\  
package NetFox; k$i76r  
import java.io.*; <6Y o%xt  
%K\_gR}V  
j_o6+R k  
public class FileAccessI implements Serializable{ ?Q]&d!U Cs  
1Ty{k^%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <DvpqlT  
RandomAccessFile oSavedFile; B&0-~o3WP  
long nPos; p6A"_b^  
4["$}O5  
)^|zuYzN  
public FileAccessI() throws IOException TMhUo#`I|  
{ .o]vjNrd/  
this("",0); s~6?p% 2]  
} H/|Mq#K  
"c\ZUx_i6  
Y 'Yoc  
public FileAccessI(String sName,long nPos) throws IOException cZe,l1$  
{ S_y!4;]ox  
oSavedFile = new RandomAccessFile(sName,"rw"); &s_[~g<  
this.nPos = nPos; x&8HBF'  
oSavedFile.seek(nPos); 9} :n  
} A%Pjg1(uX  
HH&`f3  
0vqXLFf   
public synchronized int write(byte[] b,int nStart,int nLen) +w?RW^:Q=  
{ 1,p7Sl^h  
int n = -1; yxf|Njo0  
try{ ?}D@{%O3T  
oSavedFile.write(b,nStart,nLen); +`r;3kH ..  
n = nLen; N32!*TsWs  
} Sy6Y3 ~7  
catch(IOException e) 63#Sf$p{v  
{ l5b? 'L  
e.printStackTrace (); *T$`5|  
} HpiP"Sl  
 O3bo3Cm$  
;sE;l7  
return n; I0h/x5  
} vj]-p=  
f]tc$`vb  
T$U,rOB"  
} :EJ+#  
V:4]]z L}  
N?eWf +C  
/* ycg5S rg  
**SiteInfoBean.java g)u ~GA*=  
*/ X-|Lg.s  
package NetFox; `f,SY  
FX`SaY>D  
Cu3^de@h  
public class SiteInfoBean { dE=4tqv-r  
l~kxt2&  
rK;F]ei  
private String sSiteURL; //Site's URL ~5<-&Dyp7  
private String sFilePath; //Saved File's Path ujGvrY j  
private String sFileName; //Saved File's Name &x =}m  
private int nSplitter; //Count of Splited Downloading File 4:GVZR|-  
;i\m:8!;  
8@^=k.5IK  
public SiteInfoBean() $-H#M] Gq  
{//nSplitter的缺省值为5  w~wpm7  
//default value of nSplitter is 5 GLrHb3@"N  
this("","","",5); 4loG$l+a1  
} [1K\ _  
 u;R<  
0Ah'G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,_?P[~1  
{ 2{:bv~*I0F  
sSiteURL= sURL; ~UA:_7#\M  
sFilePath = sPath; c193Or'6Y  
sFileName = sName; #/a>dK  
this.nSplitter = nSpiltter; ejP273*ah  
2x%Xx3!  
[(Ss^?AJW  
} (!`TO{!6P  
?.Z4GWyXa  
[9dW9[Z+!  
public String getSSiteURL() 3m:[o`L  
{ {}!`v%z  
return sSiteURL; YTP6m9hA+  
} vDl6TKXcu  
8D7 = ]  
0h^&`H:  
public void setSSiteURL(String value) EF1aw2  
{ r/E'#5 Q  
sSiteURL = value; `(NMHXgG+  
} }j9V0`Q  
_ T ;+*  
+72[*_ <  
public String getSFilePath() P?D;BAP2  
{ $KDH"J  
return sFilePath; 67<Ym0+ =  
} n HiE$Y  
6bj.z  
:Z rE/3_S  
public void setSFilePath(String value) -;rr! cQ?  
{ Xi vzhI4  
sFilePath = value; ;.*n77Y  
} Y v22,|:  
rq=D[vX\N(  
 5`];[M9  
public String getSFileName() ?}<4LK]  
{ q=Cc2|Ve  
return sFileName; mFoE2?Y  
} }AdA? :7A  
Z1u:OI@(  
yn&+ >{  
public void setSFileName(String value) 6%N.'wf  
{ 9cV;W\ Tw  
sFileName = value; i4"BN,NZ{  
} ,D#ssxV  
:mOHR&2xR%  
9a4Xf%!F>z  
public int getNSplitter() }\+7*|  
{ yffg_^fR  
return nSplitter; C9+`sFau@  
} q o,uOi  
yMz%s=rh  
>;|~ z\8  
public void setNSplitter(int nCount) >SS YYy  
{ hRKAs ]^j  
nSplitter = nCount; 8#?jYhT7  
} + Xc s<+b  
} fyb:eO}  
%qN_<W&Ze  
kl(id8r  
/* Rn] `_[)*~  
**Utility.java G.#`DaP  
*/ tXZE@JyuC  
package NetFox; h%2;B;p]  
,_ zivUU  
cu)ssT  
public class Utility { 3}U {~l!K  
/HlLfW  
a!OS2Tz:  
public Utility() A:{PPjs%LA  
{ 5X8GR5P  
>j&+mii  
kX0hRX  
} OC(S"&D  
P~"e=NL5  
//线程睡眠 OHEl.p]|  
public static void sleep(int nSecond) nu'r `  
{ ]Tv0+ Ao  
try{ LYYz =gvZl  
Thread.sleep(nSecond); r8]y1 Om<  
} A"yiXc-N~\  
catch(Exception e) xK7xAO  
{ k PuY[~i%  
e.printStackTrace (); m {dXN=  
} G[;GP0\N  
} gL)l)}#  
c/K:`XP~  
//日志 p,(gv])ie  
public static void log(String sMsg) Jf#Ika&px  
{ J(0E'o{ug  
System.err.println(sMsg); [:vH_(|  
} 5X4 #T&.  
]$4DhB  
[ 2WJ];FJ  
public static void log(int sMsg) [i"6\p&  
{ o7_*#5rD  
System.err.println(sMsg); G)(vd0X1  
} {c(@u6l28  
} \3WF-!xe  
:NHP,"  
-[h2fqu1  
/* nBN+.RB:(  
**TestMethod.java #![9QUvcf  
*/ ZmXO3,sf)  
package NetFox; E~4d6~s  
BXzn-S  
-@I+IKz  
public class TestMethod { [Yi;k,F:  
nfj8z@!  
$u ae8h  
public TestMethod() /i[1$/*  
{ ///xx/weblogic60b2_win.exe KxA ^?,t[  
try{ t)p . $  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3QD+&9{D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); goMv8d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ? "+g6II  
fileFetch.start(); VB}4#-dG?  
} Ifx EM  
catch(Exception e){e.printStackTrace ();} 7o99@K,  
Vf V|fuW  
z1AYXW6F  
} @5=2+ M  
T4c]VWtD  
~;QzV?%  
public static void main(String[] args) MsD@pa  
{ *WQl#JAr  
new TestMethod(); f"Z2,!Z;  
} ;^"#3_7T]  
} U+4W9zhwo  
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