自写JdbcUtil工具类&在Tomcat下的service设置实现其简化

电玩女神 2022-05-19 05:19 99阅读 0赞

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JdbcUtil.java

package JdbcUtil;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    public class JdbcUtil {
    	private static String CLASSNAME="com.mysql.jdbc.Driver";
    	private static String URL="jdbc:mysql://localhost:3306/test";
    	private static String USERNAME="root";
    	private static String PASSWORD="root";
    	private static Connection conn=null;
    	private static PreparedStatement pstm=null;
    	private static ResultSet rs=null;
    	
    	static {
    		try {
    			Class.forName(CLASSNAME);
    		} catch (ClassNotFoundException e) {
    			e.printStackTrace();
    		}
    	}
    	
    	public Connection getConnection() {
    		try {
    			conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}
    		return conn;
    	}
    	
    	public ResultSet Query(String sql,Object...param) {
    		getConnection();
    		try {
    			pstm=conn.prepareStatement(sql);
    			if(param!=null) {
    				for(int i=0;i<param.length;i++) {
    					pstm.setObject(i+1, param[i]);
    				}			
    			}
    			rs=pstm.executeQuery();
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}
    		return rs;
    	}
    	
    	public int Update(String sql,Object...param) {
    		getConnection();
    		try {
    			pstm=conn.prepareStatement(sql);
    			if(param!=null) {
    				for(int i=0;i<=param.length;i++) {
    					pstm.setObject(i+1, param[i]);
    				}
    				int i=pstm.executeUpdate();
    				return i;
    			}
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}
    		return 0;
    	}
    	
    	public void close() {
    		try {
    			if(conn!=null) {
    				conn.close();
    			}
    			if(pstm!=null) {
    				pstm.close();
    			}
    			if(rs!=null) {
    				rs.close();
    			}
    		}catch(Exception e) {
    			e.printStackTrace();
    		}
    	}
    }

Tomcat安装后的service下的Context.xml中Context标签内加入：

简化后的JdbcUtil，"//"为被简化的代码

import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    import javax.naming.Context;
    import javax.naming.InitialContext;
    import javax.sql.DataSource;
    
    public class JdbcUtil {
            //private static String CLASSNAME="com.mysql.jdbc.Driver";
            //private static String URL="jdbc:mysql://localhost:3306/test";
            //private static String USERNAME="root";
            //private static String PASSWORD="root";
            private Connection conn=null;
            private PreparedStatement pst=null;
            private ResultSet rs=null;
            /*static{
                    try {
                            Class.forName(CLASSNAME);
                    } catch (ClassNotFoundException e) {
                            e.printStackTrace();
                    }
            }*/
            
            public Connection getConnection(){
                    try {
                            //conn = DriverManager.getConnection(URL,USERNAME,PASSWORD);
                            Context context = new InitialContext();
                            DataSource ds = (DataSource)context.lookup("java:comp/env/jdbc/test");
                            conn = ds.getConnection();
                    } catch (Exception e) {
                            e.printStackTrace();
                    }
                    return conn;
            }
            
            public ResultSet query(String sql,Object... param){
                    getConnection();
                    try {
                            pst = conn.prepareStatement(sql);
                            if(param!=null){
                                    for(int i=0;i<param.length;i++){
                                            pst.setObject(i+1, param[i]);
                                    }
                            }
                            rs = pst.executeQuery();
                            return rs;
                    } catch (SQLException e) {
                            e.printStackTrace();
                    }
                    return null;
            }
            public int update(String sql,Object... param){
                    getConnection();
                    try {
                            pst = conn.prepareStatement(sql);
                            if(param!=null){
                                    for(int i=0;i<param.length;i++){
                                            pst.setObject(i+1, param[i]);
                                    }
                            }
                            int i = pst.executeUpdate();
                            return i;
                    } catch (SQLException e) {
                            e.printStackTrace();
                    }
                    return 0;
            }
            
            public void close(){
                    try{
                            if(conn!=null){
                                    conn.close();
                            }
                            if(pst!=null){
                                    pst.close();
                            }
                            if(rs!=null){
                                    rs.close();
                            }
                    }catch(Exception e){
                            e.printStackTrace();
                    }
            }
    }

[JDBC]: /images/20220519/16a25817160c4c419df41a7a3b44719c.png