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http断点续传简单实现(java)

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/* N$Gx$u3Cd  
**SiteFileFetch.java 1{o CMq/v  
*/ H=X>o.iVqi  
package NetFox; VmBLNM?  
import java.io.*; Uj k``;  
import java.net.*; 5 1 x^gX|  
6J%SkuxR  
pe,c  
public class SiteFileFetch extends Thread { #l;Ekjfz  
[n74&EH  
+Ya-h~7;g#  
SiteInfoBean siteInfoBean = null; //文件信息Bean ;i:Uoyi  
long[] nStartPos; //开始位置 _nx|ZJ  
long[] nEndPos; //结束位置 L@a-"(TN+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 C dZ;ZR  
long nFileLength; //文件长度 _rs#h)  
boolean bFirst = true; //是否第一次取文件 ACyQsmqm:  
boolean bStop = false; //停止标志 GrM~ %ng  
File tmpFile; //文件下载的临时信息 2vWkAC;   
DataOutputStream output; //输出到文件的输出流 r`<e vwIe  
}ZYK3F  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ni%^w(J3Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException t9K.Jc0  
{ zLxWyPM0;  
siteInfoBean = bean; H>DJ-lG(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^f`#8G7(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -\NB*|9m|  
if(tmpFile.exists ()) ^<% w'*gR  
{ ?: meix  
bFirst = false; DdSUB  
read_nPos(); B=Zo0 p^  
} l^Lg"m2  
else 1H[lf B  
{ /`s^.Xh  
nStartPos = new long[bean.getNSplitter()]; p:4vjh=1h  
nEndPos = new long[bean.getNSplitter()]; zkd#vAY(A  
} RM i 2Ip  
?QuFRl,ZJ  
uWfse19  
e.HN%LrhS  
} -%t0'cKn,  
iww h,(  
ol[{1KT{  
public void run() Z].>U!7W  
{ 2l!"OiB.P  
//获得文件长度 sztnRX_  
//分割文件 N %?o-IY  
//实例FileSplitterFetch t]@ Zd*  
//启动FileSplitterFetch线程 R]V`t^1  
//等待子线程返回 A?7%q^;E  
try{ d&ZwVF!  
if(bFirst) VJ$C)0xQA  
{ $PTedJ}*Y  
nFileLength = getFileSize(); /=3g-$o{`  
if(nFileLength == -1) O]PfQ  
{ _ssHRbE  
System.err.println("File Length is not known!"); <wSmfg,yF  
} .K7A!;  
else if(nFileLength == -2) h)<42Y  
{ Vm.u3KE  
System.err.println("File is not access!"); W*s`1O>  
} BF_k~  
else _*;cwMne-  
{ UwM}!K7)G  
for(int i=0;i<nStartPos.length;i++) z)]EB6uRg  
{ Q3/q%#q>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tL).f:?  
} GqAedz;.  
for(int i=0;i<nEndPos.length-1;i++) yNT2kB'  
{ (dT!u8Oe  
nEndPos = nStartPos[i+1]; i ;tA<-$-  
} pIrAGA;  
nEndPos[nEndPos.length-1] = nFileLength; *K98z ?  
} 8bysg9H0  
} Q O?ha'Sl  
>3kR~:;  
L.Lt9W2fi  
//启动子线程 @t2 Q5c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d,[KcX  
for(int i=0;i<nStartPos.length;i++) y$&a(S]  
{ y-@!, @e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E:o:)h?$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), A,og9<+j-  
nStartPos,nEndPos,i); I/> IB   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Nb8<8O ^  
fileSplitterFetch.start(); f|G7L5-  
} mQvKreo~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YH[_0!JY^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2(rZ@Wl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `MwQ6%lf  
nEndPos = " + nFileLength); =%u|8Ea*`  
// fileSplitterFetch[nPos.length-1].start(); hHg g H4T  
]Tl\9we  
b mm@oi  
//等待子线程结束 FezW/+D  
//int count = 0; qN0#=X  
//是否结束while循环 |)4$\<d  
boolean breakWhile = false; 8k1 r|s@d  
&`Di cfD  
aK&+p#4t  
while(!bStop) t? A4xk  
{ _%2Umy|  
write_nPos(); ^sOm7S{  
Utility.sleep(500); 0V#t ;`Q3  
breakWhile = true; m c+wRx  
G}-.xj]  
qQcC[50  
for(int i=0;i<nStartPos.length;i++) }>w  
{ 5Hm!5:ZB  
if(!fileSplitterFetch.bDownOver) D+)=bPMe  
{ |Hm'.-   
breakWhile = false; UjDF  
break; u#M)i30j  
} s4gNS eA  
} r^E]GDz  
if(breakWhile) 9sCk\`n  
break; Qkib;\2  
;F""}wzn  
tv OAN|+F  
//count++; 9f^PR|F  
//if(count>4) BR^J y<^F'  
// siteStop(); 6XAr8mw9  
} 9xQ 8`7  
ij i.3-  
hcgc =$^  
System.err.println("文件下载结束!"); @,4%8E5  
} IOkC[([  
catch(Exception e){e.printStackTrace ();} ^CPfo/!  
}  ;Z q~w  
Dw=Z_+J  
)6Q0f  
//获得文件长度 8}{o2r@  
public long getFileSize() yJ8}*Gj&  
{ 3> #mO}\  
int nFileLength = -1; P"x-7>c>Y  
try{ | NU0tct^  
URL url = new URL(siteInfoBean.getSSiteURL()); R5eB,FN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pRwGv  
httpConnection.setRequestProperty("User-Agent","NetFox"); q83~j `ZJ$  
kr(<Y|  
2-V)>98  
int responseCode=httpConnection.getResponseCode(); " q^#39i?  
if(responseCode>=400) f4k5R  
{ =/g$bZ  
processErrorCode(responseCode); Dw`m>'J0  
return -2; //-2 represent access is error uUz`=4%A  
} Ejms)JK+  
2d2@J{  
~$4.Mf,u  
String sHeader; F[kW:-ne@Z  
e:J'&r& 1  
h Y}/Y  
for(int i=1;;i++) ZjZhz`  
{ H_?B{We  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "Ug/ ',jkV  
//Utility.log(in.readLine()); r)p2'+}pV  
sHeader=httpConnection.getHeaderFieldKey(i); DMQNr(w{!2  
if(sHeader!=null) N<06sRg#  
{ (.,'}+1  
if(sHeader.equals("Content-Length")) F@ $RV_M  
{ WY"Y)S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ``$%L=_m  
break; xIQ/$[&v  
} 0TO_1 0D  
} nU&NopD+*G  
else \- =^]]b=  
break; S\9t4Ki_'  
} b0YiQjS6>  
} I f3{E  
catch(IOException e){e.printStackTrace ();} -XVEV  
catch(Exception e){e.printStackTrace ();} <!~1{`n%9J  
c6,s+^^  
G#e9$!  
Utility.log(nFileLength); d1V^2Hb?  
Pr5g6I'G   
.Iw ur;/\  
return nFileLength; _ktK+8*6`  
} %j'G.*TD  
pw,O"6J*  
[1b6#I"x  
//保存下载信息(文件指针位置) )sW6iR&_i  
private void write_nPos() [ WV@w  
{ l'*^$qc  
try{ Ot`LZ"H:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sI&i{D  
output.writeInt(nStartPos.length); 'tb(J3ZP  
for(int i=0;i<nStartPos.length;i++) -)1-~7 r  
{ 6a4'xq7  
// output.writeLong(nPos); A~Z6jK  
output.writeLong(fileSplitterFetch.nStartPos); ,3Wb4so  
output.writeLong(fileSplitterFetch.nEndPos); m'cz5mcD  
} JEWL)  
output.close(); 3CR@' qG-  
} (C daE!I4Q  
catch(IOException e){e.printStackTrace ();} D]IBB>F  
catch(Exception e){e.printStackTrace ();} sm 's-gD  
} #z ON_[+s9  
_u&>&,:q  
C:`;d&d  
//读取保存的下载信息(文件指针位置) n*4lz^LR  
private void read_nPos() bIgh@= 2  
{ {5^K Xj$B  
try{ JD6aiI!Su  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iI5+P`sE&J  
int nCount = input.readInt(); IY=/` g  
nStartPos = new long[nCount]; &V'519vmoZ  
nEndPos = new long[nCount]; n(g)UNx  
for(int i=0;i<nStartPos.length;i++) ypx: )e"/  
{ )4l>XlQ&  
nStartPos = input.readLong(); GCDwWCxh  
nEndPos = input.readLong(); ^+ZgWS^%  
} '77~{jy  
input.close(); ? ^M /[@  
} U@G"`RYl  
catch(IOException e){e.printStackTrace ();} .it#`Yz;  
catch(Exception e){e.printStackTrace ();} LL&ud_Y  
} ~ 9GOk;{~&  
QK)){ cK  
zuSq+px L@  
private void processErrorCode(int nErrorCode) HPg3`Ul  
{ Ck\7F?S  
System.err.println("Error Code : " + nErrorCode); :.k ZR;  
} {~SaRB2<'  
{( #zcK  
!/`$AXO  
//停止文件下载 DAfyK?+UL  
public void siteStop() bLzs?eos  
{ Z(j{F<\jS  
bStop = true; )VSwT x&  
for(int i=0;i<nStartPos.length;i++) (hIF]>,kl  
fileSplitterFetch.splitterStop(); ?38lHn`FyQ  
>nzu],U  
-w1@!Sdd  
} %Y]=1BRk}  
} @@@=}!<H=  
//负责部分文件的抓取 :_5/u|{  
**FileSplitterFetch.java y}FZD?"  
*/ ~e `Bq>  
package NetFox; $= B8qZ+  
oc7$H>ET1  
K*q[(,9  
import java.io.*; .f:n\eT):  
import java.net.*; V8WFQdXc  
%<"}y$J  
0fm*`4Q  
public class FileSplitterFetch extends Thread { "T2"]u<52  
k1^\|   
hA}~es=c  
String sURL; //File URL Tlq-m2]  
long nStartPos; //File Snippet Start Position eg/<[ A:  
long nEndPos; //File Snippet End Position .B72C[' c  
int nThreadID; //Thread's ID b0v:12q  
boolean bDownOver = false; //Downing is over R!(ZMRMn  
boolean bStop = false; //Stop identical  foRD{Hx  
FileAccessI fileAccessI = null; //File Access interface  R'}95S<  
FOwnxYGVf  
q5x[~]?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7y^%7U \  
{ lDc-W =X=  
this.sURL = sURL; fX~'Zk\u  
this.nStartPos = nStart; g7\,{Bw#E  
this.nEndPos = nEnd; oVvc?P  
nThreadID = id; dY7'OAUyVl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2)X4y"l  
} G{Yz8]m  
"9!d]2.-Vk  
 =<}<Ny  
public void run() Cx<0 H  
{ /./"x~@  
while(nStartPos < nEndPos && !bStop) {q%Sx*k9[  
{ uo\ .7[1  
h RC  
QaIjLc~W  
try{ *N'K/36;  
URL url = new URL(sURL); P{OAV+cG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A4C+5R  
httpConnection.setRequestProperty("User-Agent","NetFox"); : _e#  
String sProperty = "bytes="+nStartPos+"-"; :bu>],d-8'  
httpConnection.setRequestProperty("RANGE",sProperty); bmgncwlz  
Utility.log(sProperty); +mj*o(  
K6/@]y%Wr  
ncu`vYI.  
InputStream input = httpConnection.getInputStream(); /1N6X.Zb  
//logResponseHead(httpConnection); (jjTK'0[  
Q;11N7+  
Kt@M)#  
byte[] b = new byte[1024]; ~Q {QM:k  
int nRead; 1 `^Rdi0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5=Xy,hmnC  
{ "Z Htr<+  
nStartPos += fileAccessI.write(b,0,nRead); L`f^y;Y.  
//if(nThreadID == 1) >~%e$a7}+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *IgE)N >  
} **9x?s  
ZkL8e  
NBl+_/2'w  
Utility.log("Thread " + nThreadID + " is over!"); f-DL:@crU  
bDownOver = true; oSiMpQu08  
//nPos = fileAccessI.write (b,0,nRead); {3;AwhN0H  
} :w}{$v}#D;  
catch(Exception e){e.printStackTrace ();} valtev0<  
} Xq'cA9v=$J  
} ! cKz7?w  
? WJ> p  
|,9JNm$  
//打印回应的头信息 XE^)VLH:  
public void logResponseHead(HttpURLConnection con) !.2<| 24  
{ fYKOJ5f  
for(int i=1;;i++) SGb;!T *  
{ %ZHP2j %~  
String header=con.getHeaderFieldKey(i); (c0A.L)  
if(header!=null) z/i+EE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2,ECYie^  
Utility.log(header+" : "+con.getHeaderField(header)); YK|bXSA[  
else %%(R@kh9  
break; Y5fLmPza  
} DNGvpKY@  
} P[s8JDqu  
*~w[eH!!  
+`?Y?L^ J  
public void splitterStop() 'SQG>F Uy  
{ ECv)v  
bStop = true; y:v,j42%  
} UH3sH t  
Mq';S^  
wAnb Di{W  
} k,euhA/&  
C8F7bG8c  
V5}B:SUB  
/* Z7 E  
**FileAccess.java @?h/B=5 6  
*//文件访问(定位,写) @&[T _l  
package NetFox; 1S@vGq}  
import java.io.*; l<M'=-Y  
T|tOTk  
m3o,@=b  
public class FileAccessI implements Serializable{ ~'R(2[L!;  
aZ\UrV4,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y8fsveX  
RandomAccessFile oSavedFile; 'M3">$N  
long nPos; qKJSj   
ayAo^q  
c6Y\n%d&  
public FileAccessI() throws IOException z0/} !  
{ WJ*n29^N^h  
this("",0); Qt|c1@J  
} ?McQr1  
4 B*0M  
aF7nvu*N  
public FileAccessI(String sName,long nPos) throws IOException ([xo9FP;  
{ 4b:s<$TZ  
oSavedFile = new RandomAccessFile(sName,"rw"); /T. KbLx~q  
this.nPos = nPos; vVL@K,q  
oSavedFile.seek(nPos); ne^imht  
} ^{8Gt @  
6 PxW8pn  
-j&Tc` j_  
public synchronized int write(byte[] b,int nStart,int nLen) |{,KRO0P  
{ [d* ~@P  
int n = -1; %$TGzK1  
try{ 8/K!SpM*d  
oSavedFile.write(b,nStart,nLen); _D|^.)=U|  
n = nLen; 0q&'(-{s1  
}  YBnA+l*  
catch(IOException e) eAqz3#_My  
{ IJ/sX_k  
e.printStackTrace (); uPniLx\t:  
} (!:cen~|[  
pC_O:f>vJ  
H OBP`lf  
return n; MCdx?m3]  
} 8iekEG$H  
pAk/Qxl3eo  
i<(Xr  
} mg, j:,  
`8FUX= Sh  
hI(SOsKs  
/* 57 #6yXQ  
**SiteInfoBean.java LzCw+@-umw  
*/ owPm/F  
package NetFox; %e@#ux m  
+Y+Y6Ac[}  
/6_|]ijc  
public class SiteInfoBean { Y \:0Ev  
'KPASfC  
PdVfO8-  
private String sSiteURL; //Site's URL (< =}]v  
private String sFilePath; //Saved File's Path B7z -7&TE  
private String sFileName; //Saved File's Name =V^.}WtO  
private int nSplitter; //Count of Splited Downloading File OaL\w D^  
RW P<B0)  
:g.46dp4  
public SiteInfoBean() !`7B^RZ  
{//nSplitter的缺省值为5 w/L `  
//default value of nSplitter is 5 VAXT{s&4>  
this("","","",5); yOvm`9  
} x=#VX\5k:  
J sEa23  
X*L;.@xA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B*gdgM*`  
{ *x) 8fAr  
sSiteURL= sURL; pc?>cs8  
sFilePath = sPath; z.rh]Zq  
sFileName = sName; ~l2aNVv;  
this.nSplitter = nSpiltter; $Q*<96M  
v|E"[P2e  
XerbUkZ  
} *~/OOH$"  
;Q+xK h%  
NuU9~gSQ  
public String getSSiteURL() " ZX3sfkh  
{ L_w+y  
return sSiteURL; W Yc7aciJ  
} FCkf#  
wR{'y)$  
FaBqj1O1  
public void setSSiteURL(String value) A 8 vbQ  
{ >s`J5I!  
sSiteURL = value; ^`<w&I@  
} Wpc|`e<  
@JW@-9/  
*:O.97q@h  
public String getSFilePath() G"T',~  
{ ~n/ $  
return sFilePath; +t2SzQ j>  
} M4WiT<|]R  
uf&N[M  
-WQ^gcO=7  
public void setSFilePath(String value) '<0J@^vZ  
{ !d&C>7nb  
sFilePath = value; 9 fMau  
} mYc.x  
>Yt/]ta4+  
S\CRG>  
public String getSFileName() Skz|*n|eY  
{ z]3 `*/B  
return sFileName; F]m gmYD%  
} xm6EKp:  
H'qG/@u-l  
?:Y#Tbi3  
public void setSFileName(String value) ^;c16  
{ *. &HD6Qr  
sFileName = value; v2,%K`pAU  
} %Qmk2  
Y4IGDY*  
>]%8Zx[  
public int getNSplitter() KgW:@X7wvM  
{  8L*GE  
return nSplitter; >E,U>@+  
} $F.kK%-*  
>h+349  
Kq.:G%  
public void setNSplitter(int nCount) |;A/|F0-e  
{ tDDy]==E  
nSplitter = nCount; Tg3!Rq55  
} i*eAdIi  
} RwVaZJe)l  
Rte+(- iL  
RmI1`  
/* I\ | N  
**Utility.java 1p'Le!  
*/ u>pBB@  
package NetFox; HMY@F_qY`u  
h3gWOU  
_ IeU+tS  
public class Utility { oR p:B &  
joul<t-  
6x=YQwn~  
public Utility() Npn=cLC&  
{ [\R>Xcu>  
}`yiT<z  
B}d.#G+_$x  
} 0J~Qq]g  
I?Q+9Rmm`J  
//线程睡眠 _GqS&JHSf  
public static void sleep(int nSecond) V^Rkt%JY  
{ z<]bv7V  
try{ /XS&d%y  
Thread.sleep(nSecond); m=qOg>k  
} _y .]3JNm  
catch(Exception e) `P@- %T  
{ ?*r!{3T ,u  
e.printStackTrace (); l2hG$idC  
} ) uP\>vRy  
} +CM7C%U   
~YCuO0t  
//日志 W 4YE~  
public static void log(String sMsg) 7m5Co>NkuK  
{ g<\z=H  
System.err.println(sMsg); b]gY~cbI8  
} )R{UXk3q}  
GJ 'spgz  
u1K\@jlw  
public static void log(int sMsg) w?csV8ot  
{ NBl __q  
System.err.println(sMsg); 6@4n'w{"  
} 6Gn4asoA  
} #f'DEo<b  
j?n+>/sG,  
N<z`yV  
/* ?TEK=mD#u  
**TestMethod.java ! d9AG|  
*/ \|Dei);k  
package NetFox; +yt6(7V*  
e9u@`ZC07  
0o&}mKe  
public class TestMethod { B94 &elu  
f1+qXMs  
evl -V>   
public TestMethod() DpL8'Dib  
{ ///xx/weblogic60b2_win.exe S-E++f9D~  
try{ heD,& OX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XKLF8~y8A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |LYKc.xo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .?#uxd~>  
fileFetch.start(); Sw! j=`O  
} E;-qP)yU  
catch(Exception e){e.printStackTrace ();} T'rjh"C&|  
lQt% Qx  
K%,$ V,#  
} J^H =i)A  
+ Oobb-v  
lg/sMF>z\f  
public static void main(String[] args) ^Qh-(u`  
{ v}il(w;O  
new TestMethod(); Sr y,@p)  
} h-'wV${b  
} \K`jCsT  
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