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http断点续传简单实现(java)

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/* ml0.$z  
**SiteFileFetch.java u] :m"L M  
*/ }8|[;Qa`y  
package NetFox; /={Js*  
import java.io.*; j*"3t^|-  
import java.net.*; -9 !.m  
A[IL H_w  
)#|<w9uec  
public class SiteFileFetch extends Thread { ;*ix~taL%  
'7wd$rl  
\!IMaB]  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2sNK  
long[] nStartPos; //开始位置 bNFLO Q  
long[] nEndPos; //结束位置 >Rvx[`|O!m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g4`Kp; }&'  
long nFileLength; //文件长度 |(m oWY=  
boolean bFirst = true; //是否第一次取文件 IK,|5]*Ar  
boolean bStop = false; //停止标志 :j|IP)-f  
File tmpFile; //文件下载的临时信息 gqXS~K9t  
DataOutputStream output; //输出到文件的输出流 2!&&|Mh}  
j'[m:/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) nJ4@I7Sk;  
public SiteFileFetch(SiteInfoBean bean) throws IOException gBT2)2]  
{ $aHAv/&(5  
siteInfoBean = bean; I;5R2" 3  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8[r9HC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g  %K>  
if(tmpFile.exists ()) [7(-T?_  
{ vZ/6\Cz  
bFirst = false; }X GEX:1K  
read_nPos(); 3nT Z)L }  
} lis/`B\x  
else *  tCS  
{ h)~=Dm  
nStartPos = new long[bean.getNSplitter()];  Qk!;M |  
nEndPos = new long[bean.getNSplitter()]; f\'{3I29  
} !O\;Nua  
(feTk72XX  
?USQlnr:R/  
G} eUL|S  
} x21dku<6K[  
p!]6ll^  
]yjl~3  
public void run() 9/+Nj/  
{ J=.`wZQkS  
//获得文件长度 $^u}a   
//分割文件 tiN?/  
//实例FileSplitterFetch b:qY gg  
//启动FileSplitterFetch线程 ^[%%r3"$C  
//等待子线程返回 V8eB$in  
try{ ZmOfEg|h\  
if(bFirst) D\<y)kh  
{ zF5uN:-s  
nFileLength = getFileSize(); Oj<S.fi  
if(nFileLength == -1) ["\;kJ.  
{ zlR?,h-[3  
System.err.println("File Length is not known!"); l5l>d62  
} I`z@2Z+pJ  
else if(nFileLength == -2) eEhr140  
{ \!]Ua.e<  
System.err.println("File is not access!"); G=;k=oX(  
} ?"?6,;F(4  
else .NtbL./=|  
{ ,=?{("+  
for(int i=0;i<nStartPos.length;i++) s2j['g5  
{ =^H4Yck/5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eZ"1gYqy  
} Bgmn2-  
for(int i=0;i<nEndPos.length-1;i++) iC iZJ"  
{ RwS@I /  
nEndPos = nStartPos[i+1]; T~h5B(J;  
} "c}@V*cO<d  
nEndPos[nEndPos.length-1] = nFileLength; 5*[2yKsTi  
} 7ugZE93!  
} (KvROV);  
&uC@|dbC5  
[AV4m   
//启动子线程 eNiaM6(J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `jS T  
for(int i=0;i<nStartPos.length;i++) ?\8?%Qk  
{ j~j\\Y  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hHqh{:q{v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G,;,D9jO7  
nStartPos,nEndPos,i); EyY.KxCB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wP,JjPUt  
fileSplitterFetch.start(); fDx9iHGv  
} Mi~(aah  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eT2*W$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qRbf2;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h*u`X>!!  
nEndPos = " + nFileLength); iAa;6mH  
// fileSplitterFetch[nPos.length-1].start(); "`6n6r42  
(H+'X}1  
\.mI  
//等待子线程结束 A.UUW  
//int count = 0; a<]B B$~  
//是否结束while循环 g/13~UM\  
boolean breakWhile = false; I(=V}s2  
Vf(6!iRP@  
Z,iHy3`  
while(!bStop) 0a"igq9t  
{ ioPUUUb)  
write_nPos(); <3,<\ub  
Utility.sleep(500); BB|?1"neg  
breakWhile = true; VY)s+Bx  
Nan[<  
DNP13wp@  
for(int i=0;i<nStartPos.length;i++) y^o@"IYu3  
{ If%/3UJ@  
if(!fileSplitterFetch.bDownOver) [ @4rjGwB  
{ zSb PW 6U  
breakWhile = false; -GLMmZJt  
break; G9JAcO1  
} svXR<7) #  
} ?k(\ApVHj  
if(breakWhile) dK>7fy;mv  
break; i*CZV|t US  
?.Pg\ur  
]r_;dYa  
//count++; aM4k *|H?  
//if(count>4) z2Z^~, i  
// siteStop(); 7=(Hy\Q5xH  
} a'\o 7_  
Mfv1Os:ST  
t|m=J`a{q;  
System.err.println("文件下载结束!"); q{+_ <2U|  
} 10H)^p%3+  
catch(Exception e){e.printStackTrace ();} {/pm<k=  
} ;NRF=d>  
d|4}obCt  
`O'`eY1f  
//获得文件长度 3MRc 4UlB  
public long getFileSize() Y3O#Q)-j$  
{ fxT-j s#S  
int nFileLength = -1; %w7]@VZ  
try{ I[n ^{8gz  
URL url = new URL(siteInfoBean.getSSiteURL()); UT="2*3gz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S]E.KLR?[;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ur$l Z0  
[|l?2j\  
yV^s,P1  
int responseCode=httpConnection.getResponseCode(); t'ZWc\  
if(responseCode>=400) H<1WbM:w  
{ S6[v;{xJ  
processErrorCode(responseCode); 36am-G  
return -2; //-2 represent access is error MeUaTJFEB  
} @}kv-*  
*_?dVhxf  
0:b2(^]bg  
String sHeader; H8"@iE,  
f47M#UC  
zhf.NCSt(  
for(int i=1;;i++) R"K#7{p9  
{ f^VP/rdg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KgR<E  
//Utility.log(in.readLine()); 8n>9;D5n  
sHeader=httpConnection.getHeaderFieldKey(i); MQ"xOcD*F  
if(sHeader!=null) +5XpzZ{#Wa  
{ p ]d] QMu  
if(sHeader.equals("Content-Length")) ~9j%Hm0ht  
{ -I=l8m6L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !>1@HH?I\/  
break; <qGu7y"  
} y{N-+10z  
} {P*m;a`}  
else |7zd%!  
break; 3$X'Y]5a  
} HbW0wuI  
} '} $Dgp6e  
catch(IOException e){e.printStackTrace ();} G\(|N9^:  
catch(Exception e){e.printStackTrace ();} 8(* [Fe9  
F8apH{&t  
50={%R  
Utility.log(nFileLength); 2p " WTd  
p/h Rk<K6  
4R\ Hpt  
return nFileLength; \eFR(gO+  
} [Jv@J\  
#t+d iR  
KGg3 !jY  
//保存下载信息(文件指针位置) g1( IR)U!z  
private void write_nPos() RU\/j%^  
{ LGtIm7  
try{ k1!@^A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Sy 'Dp9!|  
output.writeInt(nStartPos.length); o>VVsH  
for(int i=0;i<nStartPos.length;i++) G["c\Xux  
{ w`5xrqt@  
// output.writeLong(nPos); s)pbS}L  
output.writeLong(fileSplitterFetch.nStartPos); Sm5H_m!  
output.writeLong(fileSplitterFetch.nEndPos); ' MxrQ;|S  
} ,S!azN=  
output.close(); }+sT4'Ah>  
} F|!){=   
catch(IOException e){e.printStackTrace ();} 1@-Ns  
catch(Exception e){e.printStackTrace ();} <%" b9T`'  
} hq #?kN  
\o^2y.q:>  
G nG>7f[v  
//读取保存的下载信息(文件指针位置) qo|WXwP2  
private void read_nPos() =y-@AU8  
{ $b mLu=9  
try{ a0#J9O_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (I./ Uu%  
int nCount = input.readInt(); }1upi=+ aE  
nStartPos = new long[nCount]; 1aTB%F  
nEndPos = new long[nCount]; :*KHx|Q  
for(int i=0;i<nStartPos.length;i++) L'kmNVvYN  
{ U-3i  
nStartPos = input.readLong(); w.TuoWo>  
nEndPos = input.readLong(); =z /dcC$r  
} @!1x7%]G  
input.close(); 8#g1P4  
} BT"XT5@  
catch(IOException e){e.printStackTrace ();} PAM}*'  
catch(Exception e){e.printStackTrace ();} ^RI?ybDd  
} u`RI;KF~F  
s ']Bx=  
$A-J,_:T<  
private void processErrorCode(int nErrorCode) B]l)++~  
{ \vO,E e~#W  
System.err.println("Error Code : " + nErrorCode); 5yz(>EVH  
} _BP&n  
uwy:t!(j  
p|p l  
//停止文件下载 ^\S~?0^m  
public void siteStop() Ug<#en  
{ qO|R^De  
bStop = true; !/]WrGqbS  
for(int i=0;i<nStartPos.length;i++) |mw.qI|  
fileSplitterFetch.splitterStop(); =UfsL%  
XSyHk"g`  
?o|f':  
}  e0,|Wm  
} q}?4f *WC  
//负责部分文件的抓取 O[ef#R!  
**FileSplitterFetch.java Fkd+pS\9g~  
*/ %Da1(bBh  
package NetFox; WL"^>[Vq  
jr:7?8cH0L  
_y} T/I9  
import java.io.*; bl&nhI)w  
import java.net.*; P&^;656r  
wLnf@&jQ%  
9eQxit7  
public class FileSplitterFetch extends Thread { dx@-/^.  
y#z  
m0a?LY  
String sURL; //File URL (bH`x]h#  
long nStartPos; //File Snippet Start Position gq'Y!BBQy  
long nEndPos; //File Snippet End Position #ZrHsf P  
int nThreadID; //Thread's ID HK0! P*  
boolean bDownOver = false; //Downing is over YOmM=X+'H  
boolean bStop = false; //Stop identical 7Bd-!$j+  
FileAccessI fileAccessI = null; //File Access interface  KJaXg;,H  
yj.7'{mA  
!`Hd-&}bYz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException fy@<&U5rg  
{ %2{ %Obp'  
this.sURL = sURL; |#cm`v  
this.nStartPos = nStart; =V-|#j  
this.nEndPos = nEnd; TI,&!E?;  
nThreadID = id; FwkuC09tI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HOJs[mqB%  
} Ku} Z  
^<a t'jk6  
gL *>[@RO  
public void run() _8F`cuyW  
{ aGtf z)  
while(nStartPos < nEndPos && !bStop) oF1,QQ^dg  
{ D!Pq4'd(  
_n50C"X=&(  
zGkS^Z=(  
try{ |8l<$J  
URL url = new URL(sURL); @v)p<r^M">  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m4hg'<<V  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7>))D'l57  
String sProperty = "bytes="+nStartPos+"-"; b)qoh^  
httpConnection.setRequestProperty("RANGE",sProperty); Ki$MpA3j   
Utility.log(sProperty); &-Gqdnc  
Pama#6?OPh  
qGB{7-ru  
InputStream input = httpConnection.getInputStream(); iW%I|&  
//logResponseHead(httpConnection); H2jgO?l;!  
nG'&ZjA  
3yU.& k  
byte[] b = new byte[1024]; (mTE;s(  
int nRead; ~O oidKT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $Y/9SV,  
{ 26I_YL,S  
nStartPos += fileAccessI.write(b,0,nRead); W_\5nF  
//if(nThreadID == 1) c|B.n]Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !h23cj+V  
} IYS)7`{]  
{E9+WFz5  
mpU$ +  
Utility.log("Thread " + nThreadID + " is over!"); ,*&:2o_r  
bDownOver = true; _u5#v0Y  
//nPos = fileAccessI.write (b,0,nRead); $0>60<J  
} %7IugHH9y  
catch(Exception e){e.printStackTrace ();} K}buH\yco  
} T?tgd J  
}  #~2%)  
7byK{{/z  
Cz\e w B  
//打印回应的头信息 _/-jX  
public void logResponseHead(HttpURLConnection con) 4U+xb>  
{ lm-dW'7&  
for(int i=1;;i++) P3x= 8_#  
{  ' V^6XI  
String header=con.getHeaderFieldKey(i); 'MUv5 Th  
if(header!=null) -pf}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 59Xi3KY  
Utility.log(header+" : "+con.getHeaderField(header)); s E2D#D  
else 8 D3OOab  
break; mS$j?>m  
} tl,.fjZn  
} =[cS0Sy  
(|:M&Cna]  
vNV/eB8#S  
public void splitterStop() `.~N4+SP  
{ Rg\z<wPBG  
bStop = true; fk6%XO  
} A+ZK4]xb  
la0BiLzb]  
([T>.s  
} "d#Y}@*~o  
lT(WD}OS  
V@e?#iz  
/* LrM=*R h,O  
**FileAccess.java DCIxRPw  
*//文件访问(定位,写) (C-{B[Y  
package NetFox; r3&G)g=u  
import java.io.*; |[<_GQl  
U@_dm/;0&  
%GjM(;Tk  
public class FileAccessI implements Serializable{ p{amC ;cI$  
=9'RM>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9YIM'q>`v  
RandomAccessFile oSavedFile; :~e>Ob[,"  
long nPos; R]c+?4J  
I5 o)_nc  
X$ 0?j 1  
public FileAccessI() throws IOException u]<,,  
{ 5nv#+ap1 "  
this("",0); C%$edEi  
} :)wy.r;N  
bf ]f=;.+  
#^l L5=  
public FileAccessI(String sName,long nPos) throws IOException L-jJg,eY  
{ bhTb[r  
oSavedFile = new RandomAccessFile(sName,"rw"); u)X=Qm)  
this.nPos = nPos; r?+%?$  
oSavedFile.seek(nPos); H*RC@O_hv  
} 0%9 q8 M;  
zT =Ho   
j"ThEx0  
public synchronized int write(byte[] b,int nStart,int nLen) Y;dz,}re  
{ 2iY3Lsna  
int n = -1; [YRz*5   
try{ ?*[N_'2W+  
oSavedFile.write(b,nStart,nLen); /\ y?Y  
n = nLen; 3KR d  
} b3&zjjQ  
catch(IOException e) 9_L[w\P|4  
{ |{BIHgMh  
e.printStackTrace (); Y}t \4 di  
} 1tEgl\u\  
wKtl+}}  
kw >v:F<M  
return n; W]"zctE  
} Tzt8h\Q^z  
-[ *,^Ti`  
SN9kFFIPb=  
} UldXYtGe  
2 Wt> Mi  
"9ZID-~]  
/* N=4G=0 `ke  
**SiteInfoBean.java MW! srTQ_  
*/ 7L`A{L  
package NetFox; )IP,;<  
iZ#!O* >  
]{)a,c NG  
public class SiteInfoBean { aGrIQq/k)%  
9=vMgW  
WK ts[Z  
private String sSiteURL; //Site's URL bZnuNYty75  
private String sFilePath; //Saved File's Path ^nT/i .#_  
private String sFileName; //Saved File's Name p#01gB  
private int nSplitter; //Count of Splited Downloading File 09X01X[  
 ,V,`Jf  
#X%~B'  
public SiteInfoBean() }6p@lla,%]  
{//nSplitter的缺省值为5 PXK7b2fE.  
//default value of nSplitter is 5 6_J$UBT  
this("","","",5); ^Ew]uN>,  
} 8UXjm_B^'  
@)UZ@ ~R  
8ZM?)# `@{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5m*iE*+  
{ K#%&0D!  
sSiteURL= sURL; sd,J3  
sFilePath = sPath; $h2){*5E{  
sFileName = sName; mPOGidxix  
this.nSplitter = nSpiltter; K{x\4  
g-Mj.owu=  
X> 1,!I9  
} sT !~J4  
3VsW@SG7N  
WzPTFw[  
public String getSSiteURL() -MW_| MG  
{ %z /hf  
return sSiteURL; ~k\fhx  
} zjJ *n8l  
9E zj"  
j5K]CTz#  
public void setSSiteURL(String value) Hc!  mB  
{ B( ]M&  
sSiteURL = value; i'a?kSy  
} .\[`B.Q  
xAqb\|$^  
DwaBdN[!7  
public String getSFilePath() OglEt["  
{ n)L*  
return sFilePath; X>d"]GD  
} Q;[,Q~c[u  
`e(c^z#  
qOe+ZAJ{%N  
public void setSFilePath(String value) VeGL)  
{ aDq5C-MzG  
sFilePath = value; y[`l3;u:'  
} _a5d?Q9Z  
pf%=h |  
!g?|9  
public String getSFileName() *?Lv3}E  
{ (*Z)(O*z  
return sFileName; hLI`If/+K  
} W}--p fG  
qmnZAk  
!2 LCLN\  
public void setSFileName(String value) NMW#AZVd  
{ jq-p;-i  
sFileName = value; DQNnNsP:M-  
} 3 *d"B tg  
<A[E:*`*  
~"!] 3C,L  
public int getNSplitter() AuUd e$l_  
{ Y,GU%[+  
return nSplitter; _p# CwExuy  
} CKtB-a  
0)%YNaskj  
P<PJ)>  
public void setNSplitter(int nCount) $$D}I*^Dt  
{ Ipf|")*  
nSplitter = nCount; !,l9@eJQ  
} m#8m] Y  
} c|lu&}BS  
?Y)vGlWDW<  
`k=bL"T>\  
/* $"`- ^  
**Utility.java 3!3xCO  
*/ {kp-h2I,  
package NetFox; x9$` W  
_.>QEh5"5  
2{]`W57_=  
public class Utility { aiQ>xen5C5  
YCdS!&^UN  
!zux z  
public Utility() K)-U1JE7  
{ aHs^tPg  
{n(b{ ibl  
;6gDV`Twy  
} j Yx38_5e  
-#0qV:D  
//线程睡眠 tna .52*/  
public static void sleep(int nSecond) @xQgY*f#  
{ *n; !G8\  
try{ AcS|c:3MUy  
Thread.sleep(nSecond); O>qll 6]{@  
} `D>S;[~S7  
catch(Exception e) ~Cl){8o  
{ #OBJzf*p  
e.printStackTrace (); 6S\C}U/   
} >C7r:%  
} xgABpikC^  
rE i Ki  
//日志 7x#Ckep:I  
public static void log(String sMsg)  gG uZ8:f  
{ <!L>Exh&r  
System.err.println(sMsg); bQE};wM,  
} k xP-,MD  
uJOJ-5}yt  
"XB[|#&  
public static void log(int sMsg) 0rh]]kj  
{ |w_7_J2  
System.err.println(sMsg); WEFlV4/  
} 0="%Y ^N  
} &?VQ,+[ <  
z|=}1; (.  
kV?y0J.  
/* 9w"h  
**TestMethod.java MA;1 ;uI,  
*/ kz{/(t  
package NetFox; "Weg7mc#  
+hvO^?4j  
`1'6bp`Z  
public class TestMethod { &@%W29:  
UH]l9Aq$P  
TS/.`.gT  
public TestMethod() KQacoUHrK?  
{ ///xx/weblogic60b2_win.exe e:DkGy`-s  
try{ &L#UGp $,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .zS?9MP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8*8Zc/{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pF&(7u  
fileFetch.start(); pcau}5 .  
} !g Z67  
catch(Exception e){e.printStackTrace ();} thV>j9'  
RMX:9aQ3F  
6;C3RU]  
} UQ'\7OS  
#~SP)Ukp  
y|CP;:f;  
public static void main(String[] args) Ge,;8N88  
{ Xua+cVc\y  
new TestMethod(); !vX D  
} ^ s1Q*He  
} a-l; vDs  
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