一、准备工作
首先导入jar包：
①c3p0-0.9.1.2.jar
②commons-dbutils-1.7.jar
③mysql-connector-java-5.1.19-bin.jar
然后在src中创建c3p0-config.xml
<c3p0-config>
<default-config>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/数据库名?useUnicode=true&characterEncoding=utf-8</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="user">用户名</property>
<property name="password">密码</property>
<property name="initialPoolSize">3</property>
<property name="maxPoolSize">6</property>
<property name="maxIdleTime">1000</property>
</default-config>
</c3p0-config>
二、配置
（一）编写C3P0Conn.java
package cn.tx.commons;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import java.sql.Connection;
import java.sql.SQLException;
public class C3P0Conn {
//数据源
private static ComboPooledDataSource ds = new ComboPooledDataSource();
public static Connection getConnection(){
Connection conn = null;
try {
//获取到连接
conn = ds.getConnection();
System.out.println("C3P0连接成功！！！");
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
//关闭资源
public static void closeConntion(Connection conn){
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
（二）创建实体类Student[依照数据库]
package cn.tx.enitty;
public class Student {
private int id;
private String name;
private String sex;
private String birthday;
public Student() {
}
public Student(int id, String name, String sex, String birthday) {
this.id = id;
this.name = name;
this.sex = sex;
this.birthday = birthday;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", sex='" + sex + '\'' +
", birthday='" + birthday + '\'' +
'}'+"\n";
}
}
（二）进行增删改查
package cn.tx.dao;
import cn.tx.commons.C3P0Conn;
import cn.tx.enitty.Student;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
public class StudentDao {
private Connection conn = null;
//DBUtils工具类
private QueryRunner qr = new QueryRunner();
//查询所有的学生
public List<Student> SelectAll(){
List<Student> List = null;
//第一步获取连接
conn = C3P0Conn.getConnection();
//第二步编写sql语句
String sql = "select * from students";
try {
List = qr.query(conn,sql,new BeanListHandler<Student>(Student.class));
} catch (SQLException e) {
e.printStackTrace();
}finally {
//关闭资源
C3P0Conn.closeConntion(conn);
}
return List;
}
/*条件查询*/
public Student SelectAll2(int id,String name){
Student stu = null;
conn = C3P0Conn.getConnection();
String sql = "select * from students where id = ? and name = ?";
try {
stu = qr.query(conn,sql,new BeanHandler<Student>(Student.class),id,name);
} catch (SQLException e) {
e.printStackTrace();
}finally {
C3P0Conn.closeConntion(conn);
}
return stu;
}
//增加
public int Insert(Student st){
int i = 0;
conn = C3P0Conn.getConnection();
String sql = "insert into students(name,sex,birthday) values(?,?,?)";
try {
i = qr.update(conn,sql,st.getName(),st.getSex(),st.getBirthday());
} catch (SQLException e) {
e.printStackTrace();
}finally {
C3P0Conn.closeConntion(conn);
}
return i;
}
//删除
public int deleteConn(int id){
int i=0;
conn = C3P0Conn.getConnection();
String sql = "delete from students where id = ?";
try {
i = qr.update(conn,sql,id);
} catch (SQLException e) {
e.printStackTrace();
}finally {
C3P0Conn.closeConntion(conn);
}
return i;
}
//修改
public int updateConn(Student stu){
int i=0;
conn = C3P0Conn.getConnection();
String sql = "update students set name=?,sex=?,birthday=? where id = ?";
try {
i = qr.update(conn,sql,stu.getName(),stu.getSex(),stu.getBirthday(),stu.getId());
} catch (SQLException e) {
e.printStackTrace();
}finally {
C3P0Conn.closeConntion(conn);
}
return i;
}
public static void main(String[] args) {
StudentDao sd = new StudentDao();
//查询
// System.out.println(sd.SelectAll());
//条件查询
// System.out.println(sd.SelectAll2(8, "小思达"));
//增加
// Student student = new Student();
// student.setName("梦缘");
// student.setSex("男");
// student.setBirthday("2021-2-2");
// int i = sd.Insert(student);
// System.out.println(i);
//删除
// int i1 = sd.deleteConn(11);
// System.out.println(i1);
Student stu1 = sd.SelectAll2(8, "小思达");
System.out.println(stu1);
stu1.setName("小梦缘");
int i = sd.updateConn(stu1);
System.out.println(i);
}
}
附上结构图
