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http断点续传简单实现(java)

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/* .Wvg{ S -  
**SiteFileFetch.java p!2t/XIM  
*/ tcj3x<  
package NetFox; _qq>-{-Ym  
import java.io.*; 3("E5lI(g:  
import java.net.*; r[RO"Ej"  
U7d05y'  
2B=+p83<  
public class SiteFileFetch extends Thread { ,:?=j80m  
jI,?*n<  
=1% <  
SiteInfoBean siteInfoBean = null; //文件信息Bean r*W&SU9Z  
long[] nStartPos; //开始位置 &W-1W99auE  
long[] nEndPos; //结束位置 S *K0OUq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qiyJ4^1  
long nFileLength; //文件长度 Pxe7 \e  
boolean bFirst = true; //是否第一次取文件 LkUi^1((e  
boolean bStop = false; //停止标志 qwHP8GU  
File tmpFile; //文件下载的临时信息 [35>T3Ku  
DataOutputStream output; //输出到文件的输出流 'V(9ein^Q  
xs$ -^FnD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5q{ -RJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~`o%Y"p%rv  
{ uZ(,7>0  
siteInfoBean = bean; t-$Hti7Lk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lhduK4u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qre(3,VE5  
if(tmpFile.exists ()) IyGW>g6_.  
{ khfWU  
bFirst = false; oD~q/04!  
read_nPos(); $1;@@LSw  
} 9Gk#2  
else -v62 s  
{ _f<#+*y  
nStartPos = new long[bean.getNSplitter()]; 55vI^SSA  
nEndPos = new long[bean.getNSplitter()]; hC...tk  
} ,(&5y:o  
4W36VtQ@E  
I"r[4>>B>0  
*aS[^iX?s  
} EMMp4KKOx+  
CGJ>j}C  
Tlz~o[`&  
public void run() r>x>aJ  
{ be:=-B7!  
//获得文件长度 )dZ1$MC[  
//分割文件 3C(V<R?  
//实例FileSplitterFetch jin XK  
//启动FileSplitterFetch线程 .+dego:  
//等待子线程返回 u4.2u}A/R%  
try{ Q@? {|7:  
if(bFirst) g WHjI3;  
{ { ^ @c96&  
nFileLength = getFileSize(); ^F`\B'8MF  
if(nFileLength == -1) O (YvE  
{ `& }C *i"  
System.err.println("File Length is not known!"); vON1\$bu `  
} JzuP A I  
else if(nFileLength == -2) T,fDH!a  
{ U~YjTjbd  
System.err.println("File is not access!"); H4JwgQ  
} yDXW#q  
else pJPP6Be<  
{ 53)*i\9&  
for(int i=0;i<nStartPos.length;i++) Lo^gg#o  
{ <%EjrjdvL+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]:F?k#c  
} \4roM1&[  
for(int i=0;i<nEndPos.length-1;i++) u^]Z{K_B  
{ ^fxS=Qs+  
nEndPos = nStartPos[i+1]; 8PwPI%Pb  
} 2)47$eu  
nEndPos[nEndPos.length-1] = nFileLength; o&U/e\zy  
} Cy'! >  
} G.sf>.[  
3IDX3cM9  
-q}I; cH  
//启动子线程 :dj=kuUTbu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; YTYCv7  
for(int i=0;i<nStartPos.length;i++) e? n8S  
{ &<oDl _^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #i0f}&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), a&s&6Q|Y  
nStartPos,nEndPos,i); Q!v]njCIB7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2RC@Fu~zaU  
fileSplitterFetch.start(); dn|OY. `|  
} NGOyd1$7N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?D S|vCae  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2kVQ#JyuRI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6HR^q  
nEndPos = " + nFileLength); V}+Ui]ie|I  
// fileSplitterFetch[nPos.length-1].start(); TC^fyxq  
2&d|L|->  
DS6g_SS3  
//等待子线程结束 +n&9ZC H  
//int count = 0; mUjM5ceAXO  
//是否结束while循环 o `}(1$a>  
boolean breakWhile = false; =Z}=nS?4  
,1|0]:  
=X}s^KbI{  
while(!bStop) TOXZl3 s5#  
{ fT  
write_nPos(); vD p|9VY?  
Utility.sleep(500); /dq(Z"O_  
breakWhile = true; n>i}O!agg  
e.? ;mD  
f~Q]"I8w  
for(int i=0;i<nStartPos.length;i++) Xwt}WSdF`k  
{ /E<:=DD<  
if(!fileSplitterFetch.bDownOver) 9>hK4&m^  
{ TxXX}6  
breakWhile = false; <A@qN95m  
break; .YxcXe3#  
}  a5@XD_b  
} ;iT ZzmB  
if(breakWhile) );oE^3]f  
break; +N:=|u.g  
eL{6;.C  
LQ3J$N  
//count++; ^mu PjM+D  
//if(count>4) ^P}c0}^  
// siteStop(); NG?-dkD  
} bbxo!K m"  
)ME'qA3K  
2!;U.+(  
System.err.println("文件下载结束!"); "E}38  
} l"app]uVZ  
catch(Exception e){e.printStackTrace ();} >^ijj`{d  
} hz*H,E!>  
{axMS yp;  
pA?2UZ  
//获得文件长度 w~l%xiC  
public long getFileSize() ?QG?F9?  
{ Zia<$kAO  
int nFileLength = -1; ~5sH`w~vQ  
try{ c&;Xjy  
URL url = new URL(siteInfoBean.getSSiteURL()); BNpc-O~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :Wl`8p4]  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z2^B.r#  
`=JGlN7  
6UnWtLE  
int responseCode=httpConnection.getResponseCode(); m(eR Wx&pZ  
if(responseCode>=400) Bl!R bh\  
{ DfV'1s4y  
processErrorCode(responseCode); >{@:p`*  
return -2; //-2 represent access is error {u{8QKeC  
} Zt H{2j0  
`d6,]'  
)9'Zb`n  
String sHeader; PWbi`qF)r  
odNHyJS0  
%"g; K  
for(int i=1;;i++) 3?:?dy(3z  
{ z((9vi W  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )h,-zAnZ  
//Utility.log(in.readLine()); j^qI~|#  
sHeader=httpConnection.getHeaderFieldKey(i); ".:]? Lvt  
if(sHeader!=null) n+%tu"e  
{ cL yed3uU  
if(sHeader.equals("Content-Length")) fZF.eRP '  
{ `(Ij@8 4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7zEpuw  
break; Zq\Vq:MX  
} Q3|I.I e  
} z)0%gd|  
else $mLiEsJ  
break; v7@O ,%  
} BOf)27)  
} IM$I=5y e  
catch(IOException e){e.printStackTrace ();} fOkB|E]  
catch(Exception e){e.printStackTrace ();} +3%i7  
)*T <s  
/o]j  
Utility.log(nFileLength); Jl|^  
2E_*'RT  
fgEMn;  
return nFileLength; ;/|3U7{c  
} +U= !svE  
i8H!4l  
w;(B4^?  
//保存下载信息(文件指针位置) XX|wle1Kg  
private void write_nPos() F-I\x  
{ pSh$#]mZ`  
try{ y&{ Z"+B5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d0CFMy6  
output.writeInt(nStartPos.length); }&:F,q*  
for(int i=0;i<nStartPos.length;i++) r,-9 ]?i  
{ %5|DdpES  
// output.writeLong(nPos); 'W]oQLD^R  
output.writeLong(fileSplitterFetch.nStartPos); N_qKIc_R  
output.writeLong(fileSplitterFetch.nEndPos); @!:_r5R~N  
} o; N s-=  
output.close(); &7m)K>E27  
} 6kM'f}t[C  
catch(IOException e){e.printStackTrace ();} ;gmfWHB<  
catch(Exception e){e.printStackTrace ();} Y%A KN  
} c3G&)gU4q  
?2$0aq  
j~VHU89  
//读取保存的下载信息(文件指针位置) `.F+T)G  
private void read_nPos() PML +$  
{ j+7ok 5J#  
try{ ZFO*D79:K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;)gNe:Q  
int nCount = input.readInt(); O| zLD  
nStartPos = new long[nCount]; /aHx'TG  
nEndPos = new long[nCount]; wc7F45l4  
for(int i=0;i<nStartPos.length;i++) Q]NGd 0J  
{ ^tY$pPA  
nStartPos = input.readLong(); #Y'svn1H  
nEndPos = input.readLong(); 2*1FW v  
} D|rcSa.M  
input.close(); \QKr2|  
} kx_PMpc  
catch(IOException e){e.printStackTrace ();} i1JWdHt  
catch(Exception e){e.printStackTrace ();} jXALN  
} dgsD~.((A  
n`af2I2  
gdVajOAu  
private void processErrorCode(int nErrorCode) 0&k!=gj:>Z  
{ cgvD>VUw  
System.err.println("Error Code : " + nErrorCode); 6q]`??g.  
} JD1D(  
$bi@,&t;  
m"RE[dQ  
//停止文件下载 >i IUS  
public void siteStop() 6ISDY>p  
{ L.M|o  
bStop = true; q\gvX 76a  
for(int i=0;i<nStartPos.length;i++) mbm|~UwD  
fileSplitterFetch.splitterStop();  ;%tu;  
&}/h[v_#'  
oy!Dm4F  
} %/(>>*}Kw|  
} A7X-),D  
//负责部分文件的抓取 |~I-  
**FileSplitterFetch.java 'ffOFIz|=I  
*/ |L"!^Y#=D  
package NetFox; byUz  
[6Nw)r(a(  
z LHE;  
import java.io.*; o I6o$C  
import java.net.*; gQ=g,X4  
QC\][I>  
U%,N"]`  
public class FileSplitterFetch extends Thread { o) hQ]d  
9BM 8  
G,J~Ed  
String sURL; //File URL zrJ/Fs+s  
long nStartPos; //File Snippet Start Position u/2!v(  
long nEndPos; //File Snippet End Position s*0PJ\E2  
int nThreadID; //Thread's ID t%f6P  
boolean bDownOver = false; //Downing is over wWNHZ v&  
boolean bStop = false; //Stop identical U'tfsf/V  
FileAccessI fileAccessI = null; //File Access interface 0 w#[?.  
Sn lKPd  
&R "Q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "x)xjL  
{ F]SA1ry  
this.sURL = sURL; CL-mt5Kx#7  
this.nStartPos = nStart; {,aI0bw;  
this.nEndPos = nEnd; 7>`VZ?  
nThreadID = id; *NDM{WB|)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $MT'ZM  
} CNiUHUD  
xX ktMlI  
D/&^Y'|T  
public void run() iS"(  
{ -OS&(7  
while(nStartPos < nEndPos && !bStop) 02~+$R]L  
{ ZAG ia q  
JM@}+pX  
kr C4O2Fkj  
try{ ?5<Q+ G0r  
URL url = new URL(sURL); UA|A>c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x1}7c9n K  
httpConnection.setRequestProperty("User-Agent","NetFox"); u0@i3Po  
String sProperty = "bytes="+nStartPos+"-"; ZE*m;  
httpConnection.setRequestProperty("RANGE",sProperty); PmGW\E[ni  
Utility.log(sProperty); z|V5/"  
a3<.F&c+c  
Q6G-`&5  
InputStream input = httpConnection.getInputStream(); 2h6<'2'o1  
//logResponseHead(httpConnection); @L-3&~=  
O,kzU,zOs  
ho7L@NR  
byte[] b = new byte[1024]; {i7Wp$ug  
int nRead; L.uX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ByrK|lVM0  
{ \V#2K><  
nStartPos += fileAccessI.write(b,0,nRead); |nN{XjNfP5  
//if(nThreadID == 1) rR4_=S<Mi:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y0d a8sd)  
} E2s lpo  
]mN'Qoc  
5;5DEMe  
Utility.log("Thread " + nThreadID + " is over!"); ]i-peBxw  
bDownOver = true; `;ofQz4  
//nPos = fileAccessI.write (b,0,nRead); p. eq N  
} GN4'LU  
catch(Exception e){e.printStackTrace ();} 3f2%+2Zjt,  
} A?V[/  
} ER O'{nT&  
swBgV,;   
:3s5{s   
//打印回应的头信息 cViEvS r  
public void logResponseHead(HttpURLConnection con) Vs-])Q?7J  
{ w~NQAHAvo  
for(int i=1;;i++) =""z!%j  
{ P9)E1]Dc$  
String header=con.getHeaderFieldKey(i); fAu^eS%>7  
if(header!=null) "eq{_4dL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :@:i*2=  
Utility.log(header+" : "+con.getHeaderField(header)); brA\Fp^  
else lw4#xH-?  
break;  fWx %?J  
} CfguL@tR.  
} :esHtkyML  
d;3/Vr$t=  
BULf@8~(  
public void splitterStop() 9+G.86Iky  
{ I+,~pmn:  
bStop = true; v`"z  
} &@O]'  
[X'XxYbZ  
qn VxP&  
} 7cGc`7  
=/Ob kVYf  
`.dX@<  
/* DD3.el}6a  
**FileAccess.java wo($7'.@  
*//文件访问(定位,写) N02X*NC  
package NetFox; 0j^QY6  
import java.io.*; :Yi1#  
@5!Mr5;  
M]O _L  
public class FileAccessI implements Serializable{ O,`#h*{N  
9E/{HNkf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t6GL/M4  
RandomAccessFile oSavedFile; )[d?&GK  
long nPos; gOpi>  
v+.  n9  
*9#6N2J$M  
public FileAccessI() throws IOException 4l/hh|3@  
{ ^gb3DNV~y  
this("",0); G_GV  
} [?3]+xr :  
uD=i-IHT  
(yjx+K_[  
public FileAccessI(String sName,long nPos) throws IOException &b[ .bf  
{  L|hdV\  
oSavedFile = new RandomAccessFile(sName,"rw"); H ?Vo#/  
this.nPos = nPos; F-L!o8o  
oSavedFile.seek(nPos); I}djDtJ  
} SV2DvrIR  
,(H`E?m1w4  
J*Dt\[X  
public synchronized int write(byte[] b,int nStart,int nLen) :6k8\{^9"D  
{ RRW/.y  
int n = -1; u@j]U|FpY  
try{ Aofk<O!M  
oSavedFile.write(b,nStart,nLen); f tS^|%p  
n = nLen; @>Y.s6a  
} : +Na8\d  
catch(IOException e) $#3O:aW  
{ {}r#s>  
e.printStackTrace (); : GVyY]qBU  
} J!O{.v  
a$0,T_wD  
dNH6%1(s]0  
return n; VRuY8<E  
} bC_qoI<  
@>>8CU^~  
:@BAiKa[wa  
} G(g`>' m  
|mx)W}  
9 7/"5i9  
/* =:)p\{B  
**SiteInfoBean.java }HO3D.HE^  
*/ 4R 9lA  
package NetFox; `/ W6, ]  
v|IPus|>  
_Xs(3V@'}  
public class SiteInfoBean { Q"o* \I  
Z>0a?=1[  
}BTK+Tk8  
private String sSiteURL; //Site's URL j#}wg`P"A  
private String sFilePath; //Saved File's Path W6~aL\[  
private String sFileName; //Saved File's Name ['<Q402:.  
private int nSplitter; //Count of Splited Downloading File 5<Ly^Na:  
W 9i}w&  
]i$ <<u  
public SiteInfoBean() $ z4JUr!m  
{//nSplitter的缺省值为5 5k%Gj T  
//default value of nSplitter is 5 U/hf?T;  
this("","","",5); ~.FeLWP  
} UH8q:jOi  
S511}KPbm/  
K]~! =j)v  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9'1XZpM1  
{ VFmG\  
sSiteURL= sURL; u'Od~x^z  
sFilePath = sPath; |6]2XW  
sFileName = sName; bl8zcpdL  
this.nSplitter = nSpiltter; +JyD W%a:L  
Uq}FrK}  
#6fQ$x(F#j  
} $&fP%p  
A_h|f5  
\nfjz\"R?b  
public String getSSiteURL() ){-Tt`0(u  
{ q mJ#cmN  
return sSiteURL;  c@eQSy  
} j ^Tb=  
8IeE7  
uPe&i5YR  
public void setSSiteURL(String value) p(B^](?  
{ ,, 8hU7P  
sSiteURL = value; BM~>=emc  
} Sw1z^`  
Q7 4Q|r7  
/Bt+Ov3k  
public String getSFilePath() )Y@E5Tuk>  
{ wwvS05=[T  
return sFilePath; ,@\$PyJ  
} bD2):U*Fzo  
%S`ygc}|  
hg2a,EU\Z  
public void setSFilePath(String value) ILN Yh3  
{ sJI" m'r=Z  
sFilePath = value; aXv[~  
} ec8 iZ8h8  
M0jC:*D`"  
=d+~l  
public String getSFileName() )9pRT dT  
{ oouhP1py,  
return sFileName; +69[06F  
} `G@(Z:]f,t  
QPD[uJ(I  
`6No6.\J  
public void setSFileName(String value) 8QJ^@|7  
{ "c9T4=]&t  
sFileName = value; !7rk>YrY  
} ES4[@RX  
j1 Ns|oph1  
MH0xD  
public int getNSplitter() O:% ,.??<%  
{ q0m> NA   
return nSplitter; b] EC+.  
} {)CN.z:O  
T{CCZ"Fv  
9Sb[5_Q  
public void setNSplitter(int nCount) e) \PW1b  
{ n<)gS7  
nSplitter = nCount; yQ [n7du  
} )yl;i  
} ln1QY"g  
M?gc&2 Y  
G7qB   
/* pdw;SIoC  
**Utility.java |//D|-2  
*/ vk jHh.  
package NetFox; B4#XQ-  
P&sn IJ  
dED&-e#  
public class Utility { vY"i^a`f  
'NAC4to;;  
\yE*nZ  
public Utility() &6@# W]_  
{ zObrp  
# 0* oj/  
JS!`eO/8  
} -"CXBKHb  
E,}(jAq7  
//线程睡眠 %a=^T?8  
public static void sleep(int nSecond) n>XfXt =  
{ *SmR|Qy  
try{ XU*4MU^'  
Thread.sleep(nSecond); eZ G#op  
} [uLpm*7  
catch(Exception e) i)1013b  
{ -V F*h.'  
e.printStackTrace (); W#bOx0  
} N51e.;  
} xf7_|l  
nB9(y4  
//日志 }8LTYn  
public static void log(String sMsg) Z.%0yS_T  
{ P+Q}bTb8  
System.err.println(sMsg); OpLo[Y\  
} lJJ`aYDp  
!+)5?o  
v.!e1ke8D*  
public static void log(int sMsg) Q/%]%d  
{ 0s72BcP  
System.err.println(sMsg); V|hr9  
} -Q MO*PY  
} GlOSCJZ  
KBg5 _+l  
QFg{.F?3q>  
/* <HfmNhI85(  
**TestMethod.java <-(n48  
*/ \sEH)$R'  
package NetFox; 6 =H]p1p~O  
L;i(@tp|v  
IJk<1T7:(W  
public class TestMethod { 2uzy]faM  
>$:_M*5  
 nJ|M  
public TestMethod() d "%6S*dL  
{ ///xx/weblogic60b2_win.exe ]j+J^g  
try{ ,382O$C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0x2[*pJ|IW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1EHL8@.M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M `49ydh&  
fileFetch.start(); *3A)s O  
} 6R|^IPOGp  
catch(Exception e){e.printStackTrace ();} 5_[we1$P  
S7h?tR*u  
FT Ytf4t  
} % pQi}x  
43s8a  
)ZMR4U$+v  
public static void main(String[] args) aflBDo1c  
{  jAxrU  
new TestMethod(); pnp)- a*7  
} ZkmY pi[  
} *q*$%H  
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