DDR爱好者之家 Design By 杰米
本文实例讲述了基于jsp+servlet实现的简单博客系统。分享给大家供大家参考。具体如下：
没有用框架写的 小博客， 代码大量重复。
个人感觉重复代码对于新手还是有好处的，我也是新手，见谅。
完整实例代码点击此处本站下载。
1. servlet
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package Servlet;
import blog.BlogBean;
import blog.BlogRepositoryJDBC;
import blog.PagerUtil;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLDecoder;
import java.util.List;
import javax.enterprise.context.RequestScoped;
import javax.enterprise.context.SessionScoped;
import javax.inject.Inject;
import javax.inject.Named;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(name = "PageListServlet", urlPatterns = {"/page/*", ""})
public class ListAllServlet extends HttpServlet {
@Inject
private BlogRepositoryJDBC blogdao;
@Inject
private PagerUtil pagerUtil;
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
int pg;
String s = request.getRequestURI();
String searchContent = request.getParameter("search");
if (s.matches(request.getContextPath() + "/page/" + "\\d")) {
String pgnum = s.replaceAll(request.getContextPath() + "/page/", "");
pg = Integer.parseInt(pgnum);
} else if (s.matches(request.getContextPath() + "/")) {
pg = 1;
} else {
getServletContext().getRequestDispatcher("/errorpage.jsp").forward(request, response);
return;
}
List<BlogBean> bloglist;
boolean isNullRequest = (searchContent == null || "".equals(searchContent));
if (isNullRequest) {
bloglist = blogdao.getBloglist();
} else {
bloglist = blogdao.listBlogByKey(searchContent);
}
if (!pagerUtil.isValidPg(bloglist, pg)) {
getServletContext().getRequestDispatcher("/errorpage.jsp").forward(request, response);
return;
}
pagerUtil.fillValue(bloglist, pg);
String pageURLBase = getServletContext().getContextPath();
String pageURLparam = isNullRequest "" : "" + searchContent;
request.setAttribute("pageURLBase", pageURLBase);
request.setAttribute("pageURLparam", pageURLparam);
request.setAttribute("bloglist", bloglist);
getServletContext().getRequestDispatcher("/blog.jsp").forward(request, response);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
2. dao
package blog;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import javax.enterprise.context.ApplicationScoped;
import javax.inject.Inject;
import javax.inject.Named;
import javax.sql.DataSource;
@ApplicationScoped
@Named
public class BlogRepositoryJDBC implements BlogRepository {
@Resource(lookup = "jdbc/sample")
private DataSource ds;
private ArrayList<BlogBean> bloglist;
private Set<String> tagSet;
private Set<String> categorySet;
private Map<String,Integer> dateMap;
@PostConstruct
private void init() {
refreshCache();
}
@Override
public int addBlog(BlogBean blogi) {
String sql = "INSERT INTO POSTS VALUES (";
Connection conn = null;
PreparedStatement ps = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, blogi.getBlogTitle());
ps.setString(2, blogi.getCategory());
ps.setString(3, blogi.getTag());
ps.setDate(4, new java.sql.Date(blogi.getPostDate().getTime()));
ps.setString(5, blogi.getContent());
out = ps.executeUpdate();
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, null);
}
refreshCache();
return out;
}
@Override
public int deleteBlog(String blogName) {
String sql = "DELETE FROM POSTS WHERE HEAD = ";
Connection conn = null;
PreparedStatement ps = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, blogName);
out = ps.executeUpdate();
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, null);
}
refreshCache();
return out;
}
@Override
public int updateBlog(BlogBean blog, String oldhead) {
String sql = "UPDATE POSTS SET HEAD=";
PreparedStatement ps = null;
Connection conn = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, blog.getBlogTitle());
ps.setString(2, blog.getCategory());
ps.setString(3, blog.getTag());
ps.setDate(4, new java.sql.Date(blog.getPostDate().getTime()));
ps.setString(5, blog.getContent());
ps.setString(6, oldhead);
out = ps.executeUpdate();
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, null);
}
refreshCache();
return out;
}
@Override
public List<BlogBean> ListAllBlog() {
bloglist = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS ORDER BY POSTDATE DESC";
Connection conn = null;
Statement ss = null;
ResultSet rs = null;
int out = 0;
try {
conn = ds.getConnection();
ss = conn.createStatement();
rs = ss.executeQuery(sql);
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
bloglist.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ss, rs);
}
return bloglist;
}
@Override
public List listBlogByKey(String keyword) {
List<BlogBean> list = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS WHERE HEAD LIKE ";
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, "%" + keyword + "%");
rs = ps.executeQuery();
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
list.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, rs);
}
return list;
}
@Override
public List listBlogByContent(String keyword) {
List<BlogBean> list = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS WHERE CONTENT LIKE ";
PreparedStatement ps = null;
ResultSet rs = null;
Connection conn = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, "%" + keyword + "%");
rs = ps.executeQuery();
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
list.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, rs);
}
return list;
}
public Set listAllTags() {
tagSet = new HashSet<String>();
String sql = "SELECT TAG FROM POSTS ";
Connection conn = null;
Statement ss = null;
ResultSet rs = null;
try {
conn = ds.getConnection();
ss = conn.createStatement();
rs = ss.executeQuery(sql);
while (rs.next()) {
String tags = rs.getString(1);
String[] Arraytags = tags.split(",");
tagSet.addAll(Arrays.asList(Arraytags));
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ss, rs);
}
return tagSet;
}
public List listBlogByTag(String keyword) {
List<BlogBean> list = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS WHERE TAG LIKE ";
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, "%" + keyword + "%");
rs = ps.executeQuery();
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
list.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, rs);
}
return list;
}
public List listBlogByDate(String keyword) {
List<BlogBean> list = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS WHERE POSTDATE = ";
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, keyword );
rs = ps.executeQuery();
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
list.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, rs);
}
return list;
}
public Set listAllCategory() {
categorySet = new HashSet<String>();
String sql = "SELECT CATEGORY FROM POSTS";
Connection conn = null;
Statement ss = null;
ResultSet rs = null;
try {
conn = ds.getConnection();
ss = conn.createStatement();
rs = ss.executeQuery(sql);
while (rs.next()) {
String category = rs.getString(1);
categorySet.add(category);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ss, rs);
}
return categorySet;
}
public List listBlogByCategory(String keyword) {
List<BlogBean> list = new ArrayList<BlogBean>();
BlogBean blog;
String sql = "SELECT * FROM POSTS WHERE CATEGORY LIKE ";
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
int out = 0;
try {
conn = ds.getConnection();
ps = conn.prepareStatement(sql);
ps.setString(1, "%" + keyword + "%");
rs = ps.executeQuery();
while (rs.next()) {
blog = new BlogBean();
blog.setBlogTitle(rs.getString(1));
blog.setCategory(rs.getString(2));
blog.setTag(rs.getString(3));
blog.setPostDate(rs.getDate(4));
blog.setContent(rs.getString(5));
list.add(blog);
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ps, rs);
}
return list;
}
private void fillDateMap(){
String sql = "SELECT POSTDATE,COUNT(POSTDATE) FROM POSTS GROUP BY POSTDATE";
Connection conn = null;
Statement ss = null;
ResultSet rs = null;
dateMap = new HashMap<String,Integer>();
try {
conn = ds.getConnection();
ss = conn.createStatement();
rs=ss.executeQuery(sql);
while (rs.next()) {
dateMap.put(rs.getString(1), rs.getInt(2));
}
} catch (SQLException ex) {
Logger.getLogger(BlogRepositoryJDBC.class.getName()).log(Level.SEVERE, null, ex);
} finally {
closeEverything(conn, ss, rs);
}
}
public void test(){
for(Map.Entry<String,Integer> dd: dateMap.entrySet()){
dd.getKey();
dd.getValue();
}
}
public void refreshCache() {
ListAllBlog();
listAllTags();
listAllCategory();
fillDateMap();
}
public ArrayList<BlogBean> getBloglist() {
return bloglist;
}
public Set<String> getTagSet() {
return tagSet;
}
public Set<String> getCategorySet() {
return categorySet;
}
public Map<String, Integer> getDateMap() {
return dateMap;
}
private void closeEverything(Connection conn, Statement ps, ResultSet rs) {
if (rs != null) {
try {
rs.close();
} catch (SQLException ex) {
}
}
if (ps != null) {
try {
ps.close();
} catch (SQLException ex) {
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException ex) {
}
}
}
}
3. 运行效果截图：
希望本文所述对大家的JSP程序设计有所帮助。
DDR爱好者之家 Design By 杰米
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DDR爱好者之家 Design By 杰米
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P70系列延期，华为新旗舰将在下月发布
3月20日消息，近期博主@数码闲聊站 透露，原定三月份发布的华为新旗舰P70系列延期发布，预计4月份上市。
而博主@定焦数码 爆料，华为的P70系列在定位上已经超过了Mate60，成为了重要的旗舰系列之一。它肩负着重返影像领域顶尖的使命。那么这次P70会带来哪些令人惊艳的创新呢？
根据目前爆料的消息来看，华为P70系列将推出三个版本，其中P70和P70 Pro采用了三角形的摄像头模组设计，而P70 Art则采用了与上一代P60 Art相似的不规则形状设计。这样的外观是否好看见仁见智，但辨识度绝对拉满。
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