记一次c3p0数据库报错 Connections could not be acquired from the underlying database!

在写web登录 使用c3p0连接数据库的时候 一直报错

连续好几个 java.sql.SQLException: No suitable driver
…
Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception:
java.sql.SQLException: No suitable driver
…
java.sql.SQLException: Connections could not be acquired from the underlying database!
…
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.

折腾了两天 网上查出都是说配置文件的问题
最后把 c3p0-config.xml 文件 从com.xx.login子包移动到 src下

重启 tomcat 登录 登录成功


最后贴上代码~
DataSourceUtils.java

import com.mchange.v2.c3p0.ComboPooledDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * @Author: Cangwu
 * @Date: 2019/3/27 23:54
 */
public class DataSourceUtils {

    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();

    // 获取数据源
    public static DataSource getDataSource() {
        return dataSource;
    }

    public static void CloseResource(Connection conn , Statement stmt, ResultSet rs) {
        closeResultSet(rs);
        closeStaement(stmt);
        closeConn(conn);
    }

    public static void closeConn(Connection conn){
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }finally{
                conn = null ;
            }
        }
    }

    /**
     * 释放语句执行者
     * @param st
     * 语句执行者
     */
    public static void closeStaement(Statement st){
        if(st!=null){
            try {
                st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }finally{
                st = null ;
            }
        }
    }

    /**
     * 释放结果集
     * @param rs
     * 结果集
     */
    public static void closeResultSet(ResultSet rs){
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }finally{
                rs = null ;
            }
        }
    }
}

ServletLogin.java

import com.cangwu.utils.DataSourceUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

/**
 * @Author: Cangwu
 * @Date: 2019/3/27 20:59
 */
@WebServlet(name = "ServletLogin",urlPatterns = "/login")
public class ServletLogin extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String email = request.getParameter("email");
        String password = request.getParameter("password");
        
        // 验证码调用
        String inputCode = request.getParameter("inputCode");
        String randomCode = (String)request.getSession().getAttribute("changecode");

        QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
        String sql = "select * from tb_web where email=? and password=?";
        List<User> user = null;
        try {
            user = runner.query(sql, new BeanListHandler<User>(User.class), email, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        System.out.println(user);
        if (user != 0 && inputCode.equals(randomCode)) {
            // 跳转到成功页面
        } else {
            // 失败   
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request,response);
    }
}

c3p0-config.xml

<?xml version="1.0" encoding="utf-8"?>
<c3p0-config>
    <default-config>
        <property name="user">root</property>
        <property name="password">123</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/db_01</property>
        <property name="initialPoolSize">6</property>
        <property name="maxIdleTime">1000</property>
        <property name="maxPoolSize">50</property>
        <property name="minPoolSize">10</property>
    </default-config>
</c3p0-config>

User.java

/**
 * @Author: Cangwu
 * @Date: 2019/3/23 20:27
 */
public class User {

    private String email;
    private String password;
    private String repassword;
    private String number;
    private String username;
    private String sex;
    private String phonenum;
    private String birthday;
    private String code;

    public User() {
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getPhonenum() {
        return phonenum;
    }

    public void setPhonenum(String phonenum) {
        this.phonenum = phonenum;
    }

    public String getBirthday() {
        return birthday;
    }

    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }




    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getRepassword() {
        return repassword;
    }

    public void setRepassword(String repassword) {
        this.repassword = repassword;
    }

    @Override
    public String toString() {
        return "User{" +
                "email='" + email + '\'' +
                ", password='" + password + '\'' +
                ", repassword='" + repassword + '\'' +
                ", number='" + number + '\'' +
                ", username='" + username + '\'' +
                ", sex='" + sex + '\'' +
                ", phonenum='" + phonenum + '\'' +
                ", birthday='" + birthday + '\'' +
                ", code='" + code + '\'' +
                '}';
    }
}

多多指教