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http断点续传简单实现(java)

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/* rff_=(?i  
**SiteFileFetch.java >qy$W4  
*/ j'uzjs[  
package NetFox; ]\1H=g%Ou  
import java.io.*; lNLa:j  
import java.net.*; og?L 9  
M7fPaJKL  
IKrojK8-?  
public class SiteFileFetch extends Thread { {1"kZL  
u0Bz]Ux/Q  
`t7z LC^c  
SiteInfoBean siteInfoBean = null; //文件信息Bean K_Pbzj4(P  
long[] nStartPos; //开始位置 csFLBP  
long[] nEndPos; //结束位置 h1~/zM/`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7](aPm8  
long nFileLength; //文件长度 \zJb}NbnT  
boolean bFirst = true; //是否第一次取文件 ms&6N']  
boolean bStop = false; //停止标志 r0Zj'F_e  
File tmpFile; //文件下载的临时信息 tXCgRU  
DataOutputStream output; //输出到文件的输出流 HGao}@'  
v t_lM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {,=U]^A  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,7I    
{ "]bOpk T  
siteInfoBean = bean; oe*fgk/o9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >~l^E!<i-u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #[&9~za'"m  
if(tmpFile.exists ()) (kVxa8 0  
{ kr\#CW0?  
bFirst = false; ! GJT-[  
read_nPos(); Q5&|1m Pb  
} >l b9j>  
else W %1/: _  
{ k?}y@$[)  
nStartPos = new long[bean.getNSplitter()]; l(pP*2  
nEndPos = new long[bean.getNSplitter()]; Obx!>mI^6  
} @rv)J[7Y&  
F]L96&  
?BX}0RWMh7  
m f\tMik<  
} \Ez&?yb/  
'=+gwe M  
M4n0GWHLy  
public void run() gg.lajX  
{ U]&/F{3 im  
//获得文件长度 <M,<|Y*)  
//分割文件 ?L|Ai\|  
//实例FileSplitterFetch 0Q~\1D 9g  
//启动FileSplitterFetch线程 X"V)oC  
//等待子线程返回 q8)w Al  
try{ !<<wI'8  
if(bFirst) Jsa;pG=3&  
{ :(K JLa]  
nFileLength = getFileSize(); 3T /_#=9TV  
if(nFileLength == -1) ,T-xuNYC  
{ 6s t^-L  
System.err.println("File Length is not known!"); Us\Nmso z  
} t9.| i H  
else if(nFileLength == -2) (+nnX7V?I  
{ w5vzj%6i  
System.err.println("File is not access!"); DH"_.j  
} 3fUiYI|&7  
else ~ Zw37C9J  
{ y\n#`*5k  
for(int i=0;i<nStartPos.length;i++) @,{Qa!A>l  
{ dt Br#Te  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fRwr}n'  
} XaaR>HljJ  
for(int i=0;i<nEndPos.length-1;i++) Rw<O%i5/d  
{ .7+"KP:  
nEndPos = nStartPos[i+1]; '(zP;  
} 09=w  
nEndPos[nEndPos.length-1] = nFileLength; _U o3_us  
} l>6p')F!  
} t^=S\1"R\  
,uD}1 G<u  
[[O4_)?el  
//启动子线程 ;3iWV"&_A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q$5%9  
for(int i=0;i<nStartPos.length;i++) 4WPco"xH!  
{ ny0]Q@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P=a&>i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^[6#Kw&E  
nStartPos,nEndPos,i); (ylZ[M&B:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iM$iZ;Tp  
fileSplitterFetch.start(); +fHqGZ]  
} 4YXp,U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mln%Rd6u/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S3Fj /2Q8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s~A:*2\  
nEndPos = " + nFileLength); F5+!Gb En  
// fileSplitterFetch[nPos.length-1].start(); +1K= ]#a  
!FQS9SoO9  
O' Mma5  
//等待子线程结束 @P">4xVX{  
//int count = 0; _y:a Pn  
//是否结束while循环 \okvL2:!  
boolean breakWhile = false; H|3CZ=U?  
IH"_6s#$&  
sfp.>bMj  
while(!bStop) 9Qq%Fw_  
{ pS8`OBenA  
write_nPos(); ;,Os3  
Utility.sleep(500); !>fi3#Fi  
breakWhile = true; [7l5p(=  
v?o("I[ C  
aN';_tGvK  
for(int i=0;i<nStartPos.length;i++) } : T }N]  
{ <!-#]6  
if(!fileSplitterFetch.bDownOver) !N/?b^y  
{ 0IQ|`C.  
breakWhile = false; KcM+ 8W\  
break; ~7H?tp.Dw  
} T^g i^{  
} 4rypT-%^;  
if(breakWhile) GXR7Ug}k  
break; jF{)2|5  
U8eU[|-8O/  
LbnF8tj}h  
//count++; fK{Z{)D  
//if(count>4) b{,vZhP-  
// siteStop(); j?(@x>HA  
} ,UfB{BW  
RPkOtRKL=w  
-];Hb'M.!e  
System.err.println("文件下载结束!"); h: zi8;(  
} ze`qf%  
catch(Exception e){e.printStackTrace ();} scZ'/(b-E  
} Oe0dC9H  
(Li)@Cn%  
OQ _wsAA  
//获得文件长度 3ZqtIQY`  
public long getFileSize() <7oZV^nd *  
{ 8u Z4[  
int nFileLength = -1; nN(Q}bF  
try{ ;z o?o t/  
URL url = new URL(siteInfoBean.getSSiteURL()); ,-.=]r/s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [[Usrbf  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9!wm`'G8  
?Q6ZZQ~  
}9?fb[]  
int responseCode=httpConnection.getResponseCode(); BgwZZ<B  
if(responseCode>=400) pXe]hnY  
{ tmC9p6%  
processErrorCode(responseCode); &uJ7[m19z  
return -2; //-2 represent access is error S4%MnT6Uy  
} yF1^/y!@  
WhL 1OG  
a;0$fRy  
String sHeader; 9R|B 5.  
@"`{Sh`Y$  
hF-X8$[  
for(int i=1;;i++) Y0nuwX*{  
{ fQ,(,^!;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9'!I6;M  
//Utility.log(in.readLine()); pl.=u0 *  
sHeader=httpConnection.getHeaderFieldKey(i); <~Tfi*^+  
if(sHeader!=null) 7@i2Mz/eV  
{ MM Nz2DEy[  
if(sHeader.equals("Content-Length")) JmVha!<qk  
{ dUpOg{I.x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B'D 4]EB  
break; Alb5#tm:m  
} WR>2t&;E  
} zyFbu=d|O:  
else eC-nV)]I9  
break; s}":lXkrw  
} mQt?d?6  
} %suXp,j  
catch(IOException e){e.printStackTrace ();} .g6(07TyV  
catch(Exception e){e.printStackTrace ();} 2n5{H fpY  
:6Sb3w5h  
U_e e3KKA  
Utility.log(nFileLength); p%*! ]JRS  
HUY1nb=  
d:=:l?  
return nFileLength; 2BIOA#@t  
} veGRwir  
]i pltR7k  
V %Rz(a+c  
//保存下载信息(文件指针位置) pi?U|&.1z  
private void write_nPos() %GDs/9  
{ Gnmxp%&}P|  
try{ atWAhN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XWFuAE  
output.writeInt(nStartPos.length); ]#oqum@Yf1  
for(int i=0;i<nStartPos.length;i++) t2vo;,^euL  
{ Ic&Jhw;]z  
// output.writeLong(nPos); [KjL`  
output.writeLong(fileSplitterFetch.nStartPos); @g'SH:}  
output.writeLong(fileSplitterFetch.nEndPos); GGchNt  
} pxs`g&3yd  
output.close(); j*;/Cah]k  
} RJZ4fl  
catch(IOException e){e.printStackTrace ();} %O3 r>o=  
catch(Exception e){e.printStackTrace ();} 79Vp^GG7  
} z|>f*Z  
] Q\/si&  
?{I]!gI  
//读取保存的下载信息(文件指针位置) YNi3oG]h  
private void read_nPos() H"> }y D  
{ >|So`C3:e  
try{ kzLtI w&.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h|Uy!?l  
int nCount = input.readInt(); K-*q3oh G  
nStartPos = new long[nCount]; u.sn"G-c  
nEndPos = new long[nCount]; 6~v|pA jY  
for(int i=0;i<nStartPos.length;i++) /h'b,iYVV  
{ (Dx]!FFz  
nStartPos = input.readLong(); y|@=j~}Zq  
nEndPos = input.readLong(); U0W- X9>y  
} *QpKeI  
input.close(); gRdg3qvU  
} 5zH?1Z~*  
catch(IOException e){e.printStackTrace ();} O~AOZ^a:2  
catch(Exception e){e.printStackTrace ();} xN#. Pm~  
} B]YY[i  
$?u ^hMU=  
(S#4y  
private void processErrorCode(int nErrorCode) ?(CMm%(8  
{ 8"g.Z*  
System.err.println("Error Code : " + nErrorCode); e RjpR?!\  
} )v67wn*1A  
H A(e  
Lqv5"r7eV  
//停止文件下载 Q!VPk~~(  
public void siteStop() xl$#00|y  
{ Y-WY Q{  
bStop = true; Q[k7taoy  
for(int i=0;i<nStartPos.length;i++) KwiTnP!Dca  
fileSplitterFetch.splitterStop(); KD7 RI3'?  
cTeEND)  
v+|N7  
} nUvxO `2  
} 8y{<M"v+/  
//负责部分文件的抓取 ctL@&~*nY  
**FileSplitterFetch.java lS(?x|dO  
*/ 43Yav+G(+  
package NetFox; 'L2M  W  
oA&V,r  
6Hn3  
import java.io.*; }GCt)i_  
import java.net.*; Oj*3'?<7=  
&` u<KKF6  
0iX;%SPYz  
public class FileSplitterFetch extends Thread { \Podyh/;?  
p|M  8ww  
b!ZXQn3X<  
String sURL; //File URL ODH@ /  
long nStartPos; //File Snippet Start Position }I'g@Pw9[  
long nEndPos; //File Snippet End Position (SLAq$gvd  
int nThreadID; //Thread's ID 1v4(  
boolean bDownOver = false; //Downing is over e/m ,PE  
boolean bStop = false; //Stop identical Z?5kO-[  
FileAccessI fileAccessI = null; //File Access interface \S@;>A<J  
'%`W y@  
{qCmZn5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WKQVT I&A.  
{ 8eSIY17  
this.sURL = sURL; *Ki ],>_~  
this.nStartPos = nStart; u9FXZK7  
this.nEndPos = nEnd; +]Y&las  
nThreadID = id; +t R6[%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $3sS&i<  
} !0~$u3[b  
+?~'K&@  
u4=j!Zb8}  
public void run() e1X*}OI  
{ pCNihZ~  
while(nStartPos < nEndPos && !bStop) M ,8r{[2  
{ D!~-53f@  
++:vO  
B8_ w3;x  
try{ 5[M?O4mi  
URL url = new URL(sURL); Cd#>,,\z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1@kPl[`p'  
httpConnection.setRequestProperty("User-Agent","NetFox"); jl=<Q.Mm7  
String sProperty = "bytes="+nStartPos+"-"; !c\d(u  
httpConnection.setRequestProperty("RANGE",sProperty);  )>Oip  
Utility.log(sProperty); o)7gKWjujP  
-tSWYp{  
tH<v1LEZN  
InputStream input = httpConnection.getInputStream(); ZgLO[Bj  
//logResponseHead(httpConnection); E {d Mdz  
tqIz$84G  
s&p*.I]@>  
byte[] b = new byte[1024]; *tjE#TW  
int nRead; 2i4FIS|z0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @M?N[LG  
{ A:1O:LB=!  
nStartPos += fileAccessI.write(b,0,nRead); t#~r'5va  
//if(nThreadID == 1) nv(Pwb3B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N G1]!Vz5  
} |$":7)e H!  
AU}P`fT!  
&eT)c<yhyK  
Utility.log("Thread " + nThreadID + " is over!"); 'N],d&fu^^  
bDownOver = true; Uq&ne 1  
//nPos = fileAccessI.write (b,0,nRead); bh?Vufd%)  
} uYS?# g  
catch(Exception e){e.printStackTrace ();} =8j;!7 p  
} pc5-'; n  
} SHPaSq'&N  
Rs:<'A  
G.O0*E2V  
//打印回应的头信息 #H(|+WEu  
public void logResponseHead(HttpURLConnection con) )]!Ps` ,u  
{ rB}UFS)  
for(int i=1;;i++) [syuoJ  
{ 0b=OK0n!%  
String header=con.getHeaderFieldKey(i); 3Qe:d_  
if(header!=null) _Q/D%7[pa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j_\sdH*r  
Utility.log(header+" : "+con.getHeaderField(header)); kqSCKY1  
else {!xPq%  
break; |,5b[Y"Dt  
} 0X-u'=Bs  
} er^z:1'  
fSl+;|K n  
-[v:1\Vv  
public void splitterStop() O1coay  
{  "=H7p3  
bStop = true; ;'dw`)~jQ  
} X(1nAeQ  
GdR>S('  
9'Y~! vY  
} {J%hTjCw  
/Yc!m$uCW  
yEtSyb~GK  
/* U}6'_ PRQ  
**FileAccess.java /9|1eSUa  
*//文件访问(定位,写) |v}"UW(y  
package NetFox; tz&=v,_jc  
import java.io.*; \^?BC;s^C  
*4r 1g+0  
._=Pa)T  
public class FileAccessI implements Serializable{ 6 EE7<&  
[Zl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RP7e)?5$s  
RandomAccessFile oSavedFile; /+P 4cHv]F  
long nPos; ${KDGJ,^  
*(s+u~, I  
?.IT!M}DR  
public FileAccessI() throws IOException WO)rJr!C  
{ 6t TLyI$+  
this("",0); r`i<XGPJ%  
} -Duy: C6W  
+%6{>C+bZo  
S3:Pjz}t  
public FileAccessI(String sName,long nPos) throws IOException J+[&:]=P  
{ -fz |  
oSavedFile = new RandomAccessFile(sName,"rw"); .jZmQtc  
this.nPos = nPos; >; nE.]  
oSavedFile.seek(nPos); A"\kdxC  
} mmAikT#k  
#wNksh/J^  
HW"|Hm$Y(  
public synchronized int write(byte[] b,int nStart,int nLen) z* YkD"]B  
{ %z J)mOu  
int n = -1; AR]y p{NS  
try{ II)\rVP5  
oSavedFile.write(b,nStart,nLen); PLKp<kg  
n = nLen; IBf&'/ 8\  
} rv&(yA  
catch(IOException e) S$+vRX7  
{ ,4jkTQ*@2  
e.printStackTrace (); wZh&w<l'  
} @xm O\  
['sj'3cW-  
qWHH% L;  
return n; Va\dMv-b  
} qWGnIPk  
n(/(F `  
R(kr@hM  
} 5 1@V""m  
|J'@-*5?[8  
0V"r$7(}  
/* Cv>|>Ob#  
**SiteInfoBean.java )(9>r /bq  
*/ ?&_ -,\t  
package NetFox; CK 3]]{  
EJ.oq*W!*J  
 VD;Ot<%  
public class SiteInfoBean { V2,54YE  
U voX\  
GX&BUP\  
private String sSiteURL; //Site's URL =_\5h=`Yx  
private String sFilePath; //Saved File's Path n %"q>  
private String sFileName; //Saved File's Name 7!#x-KR~5  
private int nSplitter; //Count of Splited Downloading File "nU5c4   
efy65+~GG  
 >zFe)  
public SiteInfoBean() `g<@F^x5  
{//nSplitter的缺省值为5 6,G1:BV{K  
//default value of nSplitter is 5 BdG~y1%:  
this("","","",5); "2i{ L '  
} ZvpcjP  
.|JJyjRA+  
v98=#k!F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  Mhm3u  
{ }\:3}'S.$  
sSiteURL= sURL; hq6fDRO/4  
sFilePath = sPath; 1Zx|SBF  
sFileName = sName; HlqCL1\<  
this.nSplitter = nSpiltter; 4!i`9w$$"  
u01 'f-h  
sD7Qt  
} ;3U-ghj  
#M$[C d I$  
Jor >YB`X  
public String getSSiteURL() -ZlBg~E  
{ zIi|z}WJ  
return sSiteURL; TUIj-HSe  
} &W-L`aFd0  
wOOBW0tj  
dQYb)4ir  
public void setSSiteURL(String value) ^ ~:f02[D  
{ wdS^`nz|  
sSiteURL = value; );_g2=:#  
} ]@Y8! ,  
b4Br!PL@G  
h$)(-_c3  
public String getSFilePath() ah1d0e P  
{ G+stt(k:  
return sFilePath; mp!KPw08':  
} <{bQl L  
)XmV3.rI  
klxVsx%I{G  
public void setSFilePath(String value) f_}/JF  
{ nT..+ J)  
sFilePath = value; 9W:oo:dK F  
} P9p:x6  
SUINV_>7  
_G|hKk^,  
public String getSFileName() K 4QJDC8  
{ HYyO/U9z|I  
return sFileName; X^ckTIdR  
} 8W#/=Xh?  
?:vp3f#  
9un]}7^  
public void setSFileName(String value) n$ $^(-g@)  
{ lqn7$  
sFileName = value; B8UtD  
} 5ppOG_  
(9% ki$=}+  
7yD=~l\Bbs  
public int getNSplitter() M$~3`n*^  
{ 91qk0z`N  
return nSplitter; Ef{rY|E  
} <cNXe4(  
WSi`)@.X O  
J( JsfU4  
public void setNSplitter(int nCount) G3'>KMa.  
{ fuSfBtLPR#  
nSplitter = nCount; ^e:C{]S=  
} +%Q:  
} ,A`d!{]5  
$}V<U m  
zI$^yk-vn  
/* &E0L7?l  
**Utility.java 6E/>]3~!  
*/ }IO<Dq=[  
package NetFox; Se<]g$eK?5  
jWJq[l  
0<_|K>5dS|  
public class Utility { :,g nOfV=  
m^0r9y,  
w`=_|4wFw  
public Utility() rt%?K.S/  
{ Ko_Sx.  
'?=SnjMX  
L9Sd4L_e  
} BZq_om6  
0T7(c-  
//线程睡眠 ! Ob  
public static void sleep(int nSecond) %a=K:" oU[  
{ I$/*Pt];  
try{ ^]l^q'?>:  
Thread.sleep(nSecond); PPk\W7G  
} <~;;iM6  
catch(Exception e) '{dduHo  
{ *p:`F:  
e.printStackTrace (); .Uq?SmK  
} b~X^vXIv%%  
} e8g"QDc  
Lh3>xZy"-z  
//日志 E .^5N~.  
public static void log(String sMsg) f2Zi.?``H  
{ 28FC@&'H  
System.err.println(sMsg); cKuU#&FaV  
} ?T=] ?[  
!+T\}1f7d  
OLh`R]Sd  
public static void log(int sMsg) |$"2R3  
{ !$Aijd s5  
System.err.println(sMsg); ]T|9>o!  
} Xou1X$$z  
} )OQhtxK  
WeDeD\zy  
maAZI-H{  
/* {6{y"8  
**TestMethod.java L08>9tf`  
*/ Y$xO&\&)  
package NetFox; jy@vz,/:%5  
D`p&`]k3v  
9rXbv4{  
public class TestMethod { w}+#w8hu  
x{4Rm,Dxn  
8 2qf7`  
public TestMethod() NbOeF7cq+  
{ ///xx/weblogic60b2_win.exe j1 _ E^  
try{ j,%@%upM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xw_VK1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h4rIt3`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vvA=:J4/i)  
fileFetch.start(); (t&]u7Atr  
} j.FA!4L  
catch(Exception e){e.printStackTrace ();} } 8ZCWmd  
5v"r>q[ X  
uD4=1g6[s  
} ! `5[(lm  
Td#D\d\R  
V.zKjoky@  
public static void main(String[] args) @sQ^6FK0G  
{ +Qy*s1fit  
new TestMethod(); ~3byAL  
} 0#(K}9T)  
} uC\FW6K=m  
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10+5=?,请输入中文答案:十五