Java基础--JDBC-JavaBean

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Java基础--JDBC基础知识

class Dept

package fyl;public class Dept {private Integer deptno;private String dname;private String loc;public Integer getDeptno() {return deptno;}public void setDeptno(Integer deptno) {this.deptno = deptno;}public String getDname() {return dname;}public void setDname(String dname) {this.dname = dname;}public String getLoc() {return loc;}public void setLoc(String loc) {this.loc = loc;}}

Java查询MySQL数据库步骤

package fyl;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;public class ConnDemo {public static void main(String[] args) {try {//jdbc访问数据库的步骤//1：导入数据库的驱动包   mysql-connector-java-5.1.6-bin.jarClass.forName("com.mysql.jdbc.Driver");//静态代码块实例化一个Driver对象//2：建立连接对象String url = "jdbc:mysql://192.168.3.159:3306/scott";String user = "root";String password = "root";Connection connection = DriverManager.getConnection(url, user, password);//3：准备sql指令String sql = "SELECT deptno,dname,loc FROM dept; ";//4：执行sql的预处理对象PreparedStatement preparedStatement = connection.prepareStatement(sql);//5：执行sql，返回结果集ResultSet rs= preparedStatement.executeQuery();//6：结果集的解析，放入map或bean中List<Dept> depts =new ArrayList<Dept>();while (rs.next()) {//System.out.println(rs.getInt("deptno"));//System.out.println(rs.getString("dname"));//System.out.println(rs.getString("loc"));//System.out.println("===================");Dept dept = new Dept();dept.setDeptno(rs.getInt("deptno"));dept.setDname(rs.getString("dname"));dept.setLoc(rs.getString("loc"));depts.add(dept);}//7：关闭数据库连接rs.close();connection.close();//8：测试//9：返回给页面解析数据for (Dept dept : depts) {System.out.println("deptno="+dept.getDeptno()+"  "+"dname="+dept.getDname()+"  "+"loc="+dept.getLoc());}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

封装Util

package fyl;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;public class ConnUtil {private static final String url = "jdbc:mysql://192.168.3.159:3306/scott";private static final String user = "root";private static final String password = "root";/** * 得到数据库连接 */public static Connection getConn() {try {//1：导入数据库的驱动包   mysql-connector-java-5.1.6-bin.jarClass.forName("com.mysql.jdbc.Driver");//静态代码块实例化一个Driver对象//2：建立连接对象Connection connection = DriverManager.getConnection(url, user, password);return connection;} catch (Exception e) {e.printStackTrace();return null;}}/** * 关闭数据库连接 */public static void CloseConn(Connection conn,PreparedStatement statement,ResultSet rs) {try {if(rs!=null) rs.close();if(statement!=null) statement.close();if(conn!=null) conn.close();} catch (Exception e) {e.printStackTrace();}}/** * 查找数据 */public static List<Dept> findData() {Connection connection = null;PreparedStatement preparedStatement = null;ResultSet rs = null;List<Dept> depts = null;Dept dept = null;try {    connection = getConn();//3：准备sql指令String sql = "SELECT deptno,dname,loc FROM dept; ";//4：执行sql的预处理对象preparedStatement = connection.prepareStatement(sql);//5：执行sql，返回结果集rs= preparedStatement.executeQuery();//6：结果集的解析，放入map或bean中depts =new ArrayList<Dept>();while (rs.next()) {dept = new Dept();dept.setDeptno(rs.getInt("deptno"));dept.setDname(rs.getString("dname"));dept.setLoc(rs.getString("loc"));depts.add(dept);}return depts;} catch (Exception e) {e.printStackTrace();return null;} finally {CloseConn(connection, preparedStatement, rs);}}public static void main(String[] args) {List<Dept> depts = findData();for (Dept dept : depts) {System.out.println("deptno="+dept.getDeptno()+"  "+"dname="+dept.getDname()+"  "+"loc="+dept.getLoc());}}}

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