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http断点续传简单实现(java)

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/* i@=0fHiZQ  
**SiteFileFetch.java 0w0\TWz*   
*/ *o}LI6_u  
package NetFox; [jPUAr}  
import java.io.*; `D0>L '  
import java.net.*; tOJK~%'  
4z^ ?3@:K  
>vDa`|g  
public class SiteFileFetch extends Thread { sD|P*ir  
P}] xz Vy  
HN/ %(y  
SiteInfoBean siteInfoBean = null; //文件信息Bean v"y0D  
long[] nStartPos; //开始位置 uSeRn@  
long[] nEndPos; //结束位置 h]wahExYP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]SqLF!S(=  
long nFileLength; //文件长度 ze+_iQ5  
boolean bFirst = true; //是否第一次取文件 6qW/Td|g  
boolean bStop = false; //停止标志 Md~% e'  
File tmpFile; //文件下载的临时信息 0y>]6 8D  
DataOutputStream output; //输出到文件的输出流 YVzcV`4w(  
wT;3>%Mtr  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3?x4+ b  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6}Se$XMl  
{ <Yzk]98W5.  
siteInfoBean = bean; ,G";ny[$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \7W4)>At-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~]}V"O%,  
if(tmpFile.exists ()) lzJ[`i.  
{ "pP5;*^f  
bFirst = false; AS 5\X.%L*  
read_nPos(); _|VWf8?\  
} 5H (CP  
else dKs^Dq  
{ J^}w,r *=  
nStartPos = new long[bean.getNSplitter()]; o5!"dxR  
nEndPos = new long[bean.getNSplitter()]; K4]42#  
} qH3<,s*  
@8IY J{=  
$$U Mc-Pq  
ZG=B'4W  
} 'S_kD! BO  
wz!a;]agg  
wv.FL$f[@  
public void run() udRum7XW 3  
{ l>l)m-;O  
//获得文件长度 aNZJs<3;'D  
//分割文件  3kAmRU  
//实例FileSplitterFetch yv.Y-c=  
//启动FileSplitterFetch线程 m!{}Y]FZn  
//等待子线程返回 cY%[UK$l  
try{ c\X0*GX  
if(bFirst) Jr0D:  
{ q+A^JjzT  
nFileLength = getFileSize(); ?vHow$  
if(nFileLength == -1) q4].C|7   
{ tTWeOAF  
System.err.println("File Length is not known!"); ,XD'f  
} @,Je*5$o"  
else if(nFileLength == -2) #41fRmzC  
{ HPc7Vo(  
System.err.println("File is not access!"); deD%E-Ja  
} r"yA=d'c  
else xM ]IU <  
{ 4vri=P 2%  
for(int i=0;i<nStartPos.length;i++) .C]V==z`[4  
{ 2k\i/i/Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3j{VpacZY  
} 9fk@C/$  
for(int i=0;i<nEndPos.length-1;i++) #[.vfG  
{ 'qGKS:8  
nEndPos = nStartPos[i+1]; w]Q0}Z  
} czMu<@c [  
nEndPos[nEndPos.length-1] = nFileLength; $"P9I-\m  
} x/nlIoT  
} f1c Q*#2~  
U) tqo_  
g+5{&YD  
//启动子线程 4@,d{qp~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y{].%xM5  
for(int i=0;i<nStartPos.length;i++) {`Ekv/XWa  
{ em^|E73  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pdcP;.   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H*#L~!]  
nStartPos,nEndPos,i); Ri$wt.b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qo*,2B9R L  
fileSplitterFetch.start(); BMw_F)hTO  
} ]+1?T)<!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6S-1Wc4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X#l]%IrW!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T6s~f$G  
nEndPos = " + nFileLength); Q'f!392|  
// fileSplitterFetch[nPos.length-1].start(); 1WGcv O)<  
kcy?;b;z  
&^ECQ  
//等待子线程结束 ^;J@]&[ ~  
//int count = 0; l0c ws`V  
//是否结束while循环 3"2 8=)o  
boolean breakWhile = false; @@L@r6  
(p1y/"Xh  
ahagt9[,:F  
while(!bStop) (!h%) _?.l  
{  &!I^m  
write_nPos(); xkv2#"*v  
Utility.sleep(500); wJ_E\vP  
breakWhile = true; {}Y QB'}  
SHw%u~[hu  
>>lT-w  
for(int i=0;i<nStartPos.length;i++) hg}Rh  
{ FhJ8}at+e  
if(!fileSplitterFetch.bDownOver) l26DPtWi  
{ j M%qv  
breakWhile = false; Cm:&n|  
break; lO482l_t  
} p5<2tSD  
} (2H e]M\  
if(breakWhile) fH_G;#q  
break; (mq 7{ ;7y  
JpVV0x/Q/_  
2ql7*g?Uq@  
//count++; B_FfXFQm<  
//if(count>4) f =H,BQ  
// siteStop(); z7+y{-{Z  
} ([loWr}QR  
!!Tk'=t9"3  
0 S3~IeJ  
System.err.println("文件下载结束!"); Ndj9B|s_  
} \>0F{-cR$  
catch(Exception e){e.printStackTrace ();} pg3B^  
} S>~QuCMY  
".&x`C  
vkE[Ur>  
//获得文件长度 3zJbb3e  
public long getFileSize() ZN)a}\]  
{ %G9: M;|'  
int nFileLength = -1; =>ooB/  
try{ F(E3U'G  
URL url = new URL(siteInfoBean.getSSiteURL()); r!eCfV7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9moenkL  
httpConnection.setRequestProperty("User-Agent","NetFox"); }8E//$J  
?}*A/-Hx0U  
'T54k  
int responseCode=httpConnection.getResponseCode(); Y21,!$4gb  
if(responseCode>=400) sY?pp '}a  
{ owA3>E5t&  
processErrorCode(responseCode); ZoJ:4uo N`  
return -2; //-2 represent access is error f o])=KM  
} g`KVF"8  
Lu&2^USTO  
&wj;:f  
String sHeader; ,RFcR[ak  
Zf<M14iM  
wAE ,mw  
for(int i=1;;i++) m ys5B}  
{ =re1xR!E5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YH`/;H=$G/  
//Utility.log(in.readLine()); \LB =_W$  
sHeader=httpConnection.getHeaderFieldKey(i); nV I\Or[  
if(sHeader!=null) XZhX%OT!  
{ <\k=j{@  
if(sHeader.equals("Content-Length")) \M>+6m@w  
{ ]}Hcb)'j@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6T 2jVNg  
break; Fy-+? ~  
} 6,'v /A-  
} ehO@3%z30c  
else O~F/pJN`  
break; ;u LD_1%  
} 'tK5s>gv<  
} se](hu~w  
catch(IOException e){e.printStackTrace ();} ;czMsHu0X  
catch(Exception e){e.printStackTrace ();} iqCKVo7:M  
hx$-d}W{  
Qg+0(odd  
Utility.log(nFileLength); )%8oE3O#  
VXvr`U\  
;i`X&[y;  
return nFileLength;  N7j  
} VHX&#vm*  
BsVUEF,N  
 "m3:HS  
//保存下载信息(文件指针位置) ShanwaCDqv  
private void write_nPos() nf!RB-orF  
{ Y >-|`2Z  
try{ po_||NIY  
output = new DataOutputStream(new FileOutputStream(tmpFile));  =%AFn9q  
output.writeInt(nStartPos.length); 0 1[LPN  
for(int i=0;i<nStartPos.length;i++) _xign 3  
{ #ej^K |Qx  
// output.writeLong(nPos); FKflN  
output.writeLong(fileSplitterFetch.nStartPos); yn<z!z%mz  
output.writeLong(fileSplitterFetch.nEndPos); H<|I&nV  
} eW)(u$C|qL  
output.close(); KU[eY}   
} 6~\z]LZ  
catch(IOException e){e.printStackTrace ();} uf,4GPo,  
catch(Exception e){e.printStackTrace ();} N$J)Ow  
} T{u!4Yu  
wL,b.]  
}*l V  
//读取保存的下载信息(文件指针位置) ~I6Er6$C^  
private void read_nPos() >jAr9Blz]  
{ )F 6#n&2  
try{ N m-{$U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VY8 p[`  
int nCount = input.readInt(); z^9Yoqog  
nStartPos = new long[nCount]; MJ[#Gq\0R  
nEndPos = new long[nCount]; th8f  
for(int i=0;i<nStartPos.length;i++) P%>? O :a  
{ 4R\bU"+jZ_  
nStartPos = input.readLong(); V#!ihL/>  
nEndPos = input.readLong(); xd8UdQ, lt  
} =9n$ at$l@  
input.close(); &9\z!r6mc  
} "/hM&  
catch(IOException e){e.printStackTrace ();} i%H_ua  
catch(Exception e){e.printStackTrace ();} E!'H,#"P  
} J) v~  
_#9:cH*  
VP=(",`  
private void processErrorCode(int nErrorCode) |jm|/{lc  
{ <Fb3\T L  
System.err.println("Error Code : " + nErrorCode); 70&v`"  
} 13Ga #  
5gW`;Cdbyc  
hb9X<N+p  
//停止文件下载 c+AZ(6O ?\  
public void siteStop() 1(M0C[P  
{ 8Q^yh6z  
bStop = true; }[Uh4k8P  
for(int i=0;i<nStartPos.length;i++) CFqoD l  
fileSplitterFetch.splitterStop(); -yeQQ4b  
0m,A`*o  
TCp!4-~,  
} 49}yw3-  
} Pgg6(O9}B^  
//负责部分文件的抓取 c"t1E-Nsk  
**FileSplitterFetch.java 4vTO  #F  
*/ ` =dD6r  
package NetFox; PaV[{ CD  
&oiX/UaY  
gs 8w/  
import java.io.*; rq9{m(  
import java.net.*; MK[l*=\s  
: N ^1T6v  
Ken|!rL  
public class FileSplitterFetch extends Thread { 4cL NPl<  
Mm-FdP m  
:SG9ygq'  
String sURL; //File URL 6BVV2j)zl:  
long nStartPos; //File Snippet Start Position .%`|vGF  
long nEndPos; //File Snippet End Position )7=B]{B_  
int nThreadID; //Thread's ID Y+<C[Fiq  
boolean bDownOver = false; //Downing is over (w]w 2&Y D  
boolean bStop = false; //Stop identical FQB)rxP  
FileAccessI fileAccessI = null; //File Access interface BDxrSq,H  
:gY$/1SYD  
C<fWDLwYqV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lO8.Q"mxo  
{ F1R91V|  
this.sURL = sURL; 5/DTE:M<  
this.nStartPos = nStart; _3tHzDSG#  
this.nEndPos = nEnd;  m3 ;  
nThreadID = id; wq_c^Ioy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @8Drhx  
} (p`'Okw  
C=@BkneQ  
v83uGEq(  
public void run() shxr^   
{ IGT~@);  
while(nStartPos < nEndPos && !bStop) (}O)pqZ>  
{ a*CP1@O  
3/:O8H  
0~A<AF*t  
try{ UA{sUj+?  
URL url = new URL(sURL); Nv*x^y]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >OE.6)'Rm  
httpConnection.setRequestProperty("User-Agent","NetFox"); [Z,A quCU(  
String sProperty = "bytes="+nStartPos+"-"; u_@%}zo?5*  
httpConnection.setRequestProperty("RANGE",sProperty); yk#yrxM  
Utility.log(sProperty); qyUcjc%[  
lf0/ 0KH  
Vv' e,m  
InputStream input = httpConnection.getInputStream(); mW1Sd#0  
//logResponseHead(httpConnection); PTA;a 0A  
n)} J<  
y 4,2Xs9,  
byte[] b = new byte[1024]; >NB}Bc  
int nRead; J:f>/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {d}-SoxH  
{ I"Ji_4QV  
nStartPos += fileAccessI.write(b,0,nRead); /`hr)  
//if(nThreadID == 1) ' F`*(\#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 84 b;G4K  
} 3{Ze>yFE  
NUH;GMj,,  
Y::fcMJr;Q  
Utility.log("Thread " + nThreadID + " is over!"); ,TOLr%+v~n  
bDownOver = true; ) EEr?"  
//nPos = fileAccessI.write (b,0,nRead); 7t5X  
} %2BFbaE  
catch(Exception e){e.printStackTrace ();} yZK1bnYG|I  
} k(=\& T  
} @ 5 kKMz  
Yp 6;Y7^  
:m5& i&  
//打印回应的头信息 )oTEB#J  
public void logResponseHead(HttpURLConnection con) Qat%<;P2  
{ FvG9PPd  
for(int i=1;;i++) }yx{13:[  
{ 2-llT  
String header=con.getHeaderFieldKey(i); n8[sR;r5f  
if(header!=null) |rdG+ >  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &-<"HW  
Utility.log(header+" : "+con.getHeaderField(header)); wuzz Wq  
else ?#}=!$p  
break; :m8ED[9b  
} ||`w MWq  
} n#z^uq|v  
|GK [I  
^ eM=h  
public void splitterStop() 1GOa'bxm  
{ lx$Y-Tb^F  
bStop = true; \^Y#"zXo1  
} Ep5lm zg  
vlyq2>TfR  
(n"  )  
} 8o-?Y.2  
]~WP;o  
:m#vvH  
/* vR,HCI  
**FileAccess.java hp-< 8Mf  
*//文件访问(定位,写) ,z1# |Y  
package NetFox; n/$BdFH  
import java.io.*; C^n L{ZP,  
G8u8&|  
e"r}I!.  
public class FileAccessI implements Serializable{ /lr RbZ  
KG>.7xVWV7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 + W@r p#  
RandomAccessFile oSavedFile; Z6D4VZVF  
long nPos; ^{6Y7T]  
FT|*~_@  
iM8hGQ`  
public FileAccessI() throws IOException zNE!m:s  
{ yqejd_cd  
this("",0); *N>Qj-KAM_  
} =7e8N&-nv  
^]U2Jd  
!-N!8 0  
public FileAccessI(String sName,long nPos) throws IOException iS=T/<|?  
{ 30DpIkf  
oSavedFile = new RandomAccessFile(sName,"rw"); /;OJ=x3i  
this.nPos = nPos; N"r ;d+LTL  
oSavedFile.seek(nPos); _'I9rGlx3  
} '')G6-c/  
H ~ks"D1  
M<ad>M  
public synchronized int write(byte[] b,int nStart,int nLen) l$zNsf.  
{ ,1~Zqprn  
int n = -1; //J:p,AF  
try{ o8s&n3mY}y  
oSavedFile.write(b,nStart,nLen); ` 4k;`a  
n = nLen; s{s0#g  
} U">OdoZ,E+  
catch(IOException e) dtF6IdAf  
{ @%#(Hse  
e.printStackTrace (); kk~{2   
} Lvp/} /H/  
dtg Ja_  
PU'v o4  
return n; OW-+23)sj  
} F)gL=6h  
Qb(CH  
Fn[~5/  
} qb"!  
`Mjm/9+18  
Rp@u.C <  
/* htF&VeIte  
**SiteInfoBean.java (vI7qD_  
*/ Ce0I8B2y  
package NetFox; I* bjE '  
61mQJHl.  
N$y4>g  
public class SiteInfoBean {  >#q|Pjv]  
~(Tz <  
S;t~"87v*  
private String sSiteURL; //Site's URL +?.,pqn<=  
private String sFilePath; //Saved File's Path F;b|A`M  
private String sFileName; //Saved File's Name mdZELRu  
private int nSplitter; //Count of Splited Downloading File qnA:[H;F  
#-@{rgH  
;8T<L[ ^U  
public SiteInfoBean() .1pEq~>  
{//nSplitter的缺省值为5 yr=r? h}  
//default value of nSplitter is 5 VKs\b-1  
this("","","",5); J BwTmOvQ  
} =?f}h{8x>  
{[s<\<~B*  
nuCK7X  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V`H#|8\i  
{ {$EXI]f  
sSiteURL= sURL; I}q-J~s  
sFilePath = sPath; #E ~FF@a  
sFileName = sName; m_Rgv.gE^  
this.nSplitter = nSpiltter; R80R{Ze  
y&CUT:M6  
9.@(&  
} fC-^[Af)  
p;5WLAF  
b9Y pUm7#  
public String getSSiteURL() +p[~hM6?  
{ =CVw0'yZ  
return sSiteURL; ko:I.6-K  
} va<+)b\  
$` oA$E3  
?UxY4m%R;  
public void setSSiteURL(String value) cpy"1=K~M  
{ 3Yf$WE8#l  
sSiteURL = value; gON6jnDO  
} {c1qC zM4  
|`okIqp  
4ku/3/ 6  
public String getSFilePath() ex=~l O  
{ =aekY;/  
return sFilePath; [_0g^(`  
} j~{2fd<>  
i f"v4PHq  
\%C[l  
public void setSFilePath(String value) yjr@v!o  
{ m3WV<Cbz  
sFilePath = value; w\mF2h  
} N<{ `n;  
BmM,vllO  
aE%VH ;?  
public String getSFileName() H|Nw)*.  
{ "5YdmBy  
return sFileName; LBE".+  
} k|_2aQ02  
"4`%NA  
<oO,CXF  
public void setSFileName(String value) G<z)Ydh_  
{ C1/jA>XW  
sFileName = value; O<3,n;56Z  
}  n=&c5!  
5;{Bdvcv  
nT12[@:Tr  
public int getNSplitter() r#Mx~Zg~  
{ W<4\4  
return nSplitter; 42u\Y_^ID  
} md`ToU  
]/bE${W*]  
i#lo? \PO>  
public void setNSplitter(int nCount) ypd?mw&1}  
{ 4yA`);r62  
nSplitter = nCount; F[u%t34'  
} p4t)Z#0  
} sfV.X:ev  
=l(JJ  
m@@QT<  
/* HFr3(gNj@  
**Utility.java Wy4^mOv  
*/ >S!DIL  
package NetFox; E1C_d'  
NM@An2  
) b10%n^  
public class Utility { <C77_t  
f*],j  
(HI%C@e9  
public Utility() _Pkh`}W:  
{ p5l$On  
?a%i|Z7!  
4I*Mc%dD  
} Q.1ohj0)  
s]c$]&IGG  
//线程睡眠 &[RU.Q!_H  
public static void sleep(int nSecond) q?L(V+X  
{ _);Kb/  
try{  ?~.&Y  
Thread.sleep(nSecond); {wP|b@(1t  
} hBhkb ~Oky  
catch(Exception e) 6\;1<Sw*  
{ ra>`J_  
e.printStackTrace (); )0mDN.  
} ?U08A{ c  
} 1VFqT'  
pCc7T-"og  
//日志 %B*dj9n^q  
public static void log(String sMsg) 9C;Y5E~'L  
{ 3(+#^aw  
System.err.println(sMsg); r%pFq1/'!  
} 6t:c]G'J  
'I]"=O,  
YZRB4T9  
public static void log(int sMsg) wF8\  
{ j\f$r,4  
System.err.println(sMsg); *]WXM.R8  
} LFyceFbm  
} l7,qWSsn K  
Zk UuniO  
uR@`T18  
/* Qiw4'xQm  
**TestMethod.java 7[BL 1HI*  
*/ |nN/x<v  
package NetFox; io7U[#  
C-u/{CP  
Ok&>[qu  
public class TestMethod { ^ ~qs-.?  
%uVJL z  
Lc<xgN+cJ  
public TestMethod() /dt!J `:  
{ ///xx/weblogic60b2_win.exe L5 9oh  
try{ 2?iOB6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _M[[vXH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WgJAr73 l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !`[I>:Ex  
fileFetch.start(); 8 QF?W{NK  
} \.P}`Bpa  
catch(Exception e){e.printStackTrace ();} G*i#\   
5jV97x)BGx  
:IVMTdYf  
} o?K|[gNi  
6bKO;^0  
DhNo +"!z  
public static void main(String[] args) Nu/Qa:H_{  
{ |8 2tw|<o  
new TestMethod(); >B/&V|E  
} jne9=Als5  
} 1{x~iZa  
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