Spring学习总结二——SpringIOC容器二

一：指定bean的依赖关系

例如examplebean对象依赖examplebean1对象，那么在创建examplebean对象之前就

需要先创建examplebean1对象。

1：创建Examplebean1类：

/**
 * 
 */
package com.hlcui.dao;

/**
 * @author Administrator
 * 
 */
public class ExampleBean1 {
    public ExampleBean1() {
        System.out.println("实例化ExampleBean1...");
    }
}

2：在spring容器配置文件中配置ExampleBean1对象，并且指定bean的依赖关系

depends-on="ExampleBean1"

<!-- 实例化ExampleBean对象 -->
    <bean id="exampleBean" class="com.hlcui.dao.ExampleBean" lazy-init="true" 
    init-method="init" destroy-method="destroy" scope="singleton" depends-on="ExampleBean1"></bean>

    <!-- 实例化ExampleBean1对象 -->
    <bean id="ExampleBean1" class="com.hlcui.dao.ExampleBean1"
        lazy-init="true"></bean>

3：运行测试方法：

@Test
    /**测试bean的依赖关系*/
    public void testNewExampleBean() {
        ApplicationContext ac = getApplicationContext();
        ExampleBean eb1 = ac.getBean("exampleBean", ExampleBean.class);
        System.out.println(eb1);
    }

通过结果可以看出先实例化依赖对象，再创建对象。

二：spring实现setter注入到jdbcDatasource数据库连接参数

1：导入jar包，在spring原有的支持包的基础上导入，oracle数据库的驱动包

2：创建JDBCDataSource类

/**
 * 
 */
package com.hlcui.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * @author Administrator
 * 
 */
public class JDBCDataSource {

    private String driverClass;

    private String url;

    private String username;

    private String password;

    public String getDriverClass() {
        return driverClass;
    }

    public void setDriverClass(String driverClass) {
        try {
            Class.forName(driverClass); // 注册数据库驱动
            this.driverClass = driverClass;
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    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;
    }

    // 获取数据库连接
    public Connection getConn() throws SQLException {
        return DriverManager.getConnection(url, username, password);
    }

    // 关闭数据库连接
    public void closeConn(Connection conn) {
        if (null != conn) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

3：配置bean对象

核心代码如下：

<!-- 配置jdbc数据源 -->
    <bean id="jdbcDatasource" class="com.hlcui.dao.JDBCDataSource">
        <property name="driverClass" value="oracle.jdbc.OracleDriver"></property>
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"></property>
        <property name="username" value="system"></property>
        <property name="password" value="orcl"></property>
    </bean>

4：测试方法以及运行结果

@Test
    /**测试获取jdbc连接*/
    public void testJdbcConnection() {
        try {
            ApplicationContext ac = getApplicationContext();
            JDBCDataSource ds = ac.getBean("jdbcDatasource",
                    JDBCDataSource.class);
            System.out.println(ds.getConn());
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

从运行结果可以看出，得到了jdbc连接对象。

三：spring实现构造器注入参数

1：创建业务实体类对象User

/**
 * 
 */
package com.hlcui.dto;

/**
 * @author Administrator
 *
 */
public class User {
    private int id;
    private String name;
    private String pwd;
    private String phone;
    public User(int id, String name, String pwd, String phone) {
        super();
        this.id = id;
        this.name = name;
        this.pwd = pwd;
        this.phone = phone;
    }
    public User(String name, String pwd, String phone) {
        super();
        this.name = name;
        this.pwd = pwd;
        this.phone = phone;
    }
    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 getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((phone == null) ? 0 : phone.hashCode());
        result = prime * result + ((pwd == null) ? 0 : pwd.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        User other = (User) obj;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (phone == null) {
            if (other.phone != null)
                return false;
        } else if (!phone.equals(other.phone))
            return false;
        if (pwd == null) {
            if (other.pwd != null)
                return false;
        } else if (!pwd.equals(other.pwd))
            return false;
        return true;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", phone=" + phone
                + ", pwd=" + pwd + "]";
    }
    
}

2：创建oracle的sql脚本，并且执行sql

--创建表users
Create Table Users(
Id Number(6,2),
Name Varchar2(30),
Pwd  Varchar2(50),
Phone Varchar2(50),
Primary Key(Id),
constraint name unique(name)
);

--创建序列
Create Sequence Seq_Users;

--向表中插入数据
Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Tom','123','312123232');
Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Jack','456','312123232');
Insert Into Users (Id,Name,Pwd,Phone) Values(Seq_Users.Nextval,'Lucy','789','312123232');
commit;

3：创建UserDAO接口以及其实现类

package com.hlcui.dao;

import com.hlcui.dto.User;

/**
 * @author Administrator
 *
 */
public interface UserDAO {    
    public User findByName(String name);
}

/**
 * 
 */
package com.hlcui.dao.impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.hlcui.dao.JDBCDataSource;
import com.hlcui.dao.UserDAO;
import com.hlcui.dto.User;

/**
 * @author Administrator
 * 
 */
public class OracleUserDAO implements UserDAO {

    private JDBCDataSource jdbcDataSource;

    public OracleUserDAO(JDBCDataSource jdbcDataSource) {
        this.jdbcDataSource = jdbcDataSource;
    }

    public User findByName(String name) {
        Connection conn = null;
        PreparedStatement prep = null;
        ResultSet rs = null;
        User user = null;
        try {
            conn = jdbcDataSource.getConn();
            String sql = "select id,pwd,phone from users where name=?";
            prep = conn.prepareStatement(sql);
            prep.setString(1, name);
            rs = prep.executeQuery();
            while (rs.next()) {
                int id = rs.getInt("id");
                String pwd = rs.getString("pwd");
                String phone = rs.getString("phone");
                user = new User(id, name, pwd, phone);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return user;
    }

}

注：这里使用preparedstatement进行预编译，可以有效的防止sql注入，select * from tableName  where username='' and password = '' or 1=1,

这里的1=1是无论什么条件都会满足的，所以会登录进网站。经常使用ibatis框架的朋友对 where 1=1 and ... 比较熟悉，这里是为了防止后面的sql动态拼接

不满足条件造成 select * from tableName where 这种情况，这里区分一下。

4：在spring容器配置文件配置OracleUserDao的bean对象

<!-- 配置jdbc数据源 -->
    <bean id="jdbcDatasource" class="com.hlcui.dao.JDBCDataSource">
        <property name="driverClass" value="oracle.jdbc.OracleDriver"></property>
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"></property>
        <property name="username" value="system"></property>
        <property name="password" value="orcl"></property>
    </bean>
    
    <!-- 配置userDao对象 -->
    <bean id="userDao" class="com.hlcui.dao.impl.OracleUserDAO">
        <constructor-arg index="0" ref="jdbcDatasource"/>
    </bean>

constructor-arg元素代表构造器注入，index是参数的下表，0说明是第一个元素，如果有多个参数，可以使用如下格式：

<constructor-arg index="0">   
        <value>first parameter</value>   
    </constructor-arg>   
    <constructor-arg index="1">   
        <value>second parameter</value>   
    </constructor-arg>   

5：测试读取数据库中的user对象

@Test
    /**测试从oracle数据库中读取数据*/
    public void testGetUser() {
        ApplicationContext ac = getApplicationContext();
        UserDAO dao = ac.getBean("userDao", OracleUserDAO.class);
        User user = dao.findByName("Tom");
        System.out.println(user);
    }

成功读取User对象！