【黑马程序员-Java语言高级部分11】JDBC
Spring JDBC
主要功能
Spring框架对JDBC的简单封装。
提供了一个JDBCTemplate对象简化JDBC的开发
步骤：
导入jar包
创建JdbcTemplate对象。依赖于数据源DataSource
- JdbcTemplate template = new JdbcTemplate(ds);
调用JdbcTemplate的方法来完成CRUD的操作
update(): 执行DML语句。增、删、改语句queryForMap(): 查询结果将结果集封装为map集合，将列名作为key，将值作为value 将这条记录封装为一个map集合
queryForList(): 查询结果将结果集封装为list集合
- 注意：将每一条记录封装为一个Map集合，再将Map集合装载到List集合中
query(): 查询结果，将结果封装为JavaBean对象
- query的参数：RowMapper
- 一般我们使用BeanPropertyRowMapper实现类。可以完成数据到JavaBean的自动封装
- new BeanPropertyRowMapper<类型>(类型.class)
queryForObject()：查询结果，将结果封装为对象
使用示例
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| import cn.itcast.utils.JDBCUtils;
import org.junit.Test;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
import java.util.Date;
public class JdbcTemplateDemo {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
@Test
public void test1(){
String sql = "update emp set salary = 10000 where id = 1001";
int count = template.update(sql);
System.out.println(count);
}
@Test
public void test2(){
String sql = "insert into emp(id,ename,dept_id) values(?,?,?)";
int count = template.update(sql, 1015, "郭靖", 10);
System.out.println(count);
}
@Test
public void test3(){
String sql = "delete from emp where id = ?";
int count = template.update(sql, 1015);
System.out.println(count);
}
@Test
public void test4(){
String sql = "select * from emp where id = ? or id = ?";
Map<String, Object> map = template.queryForMap(sql, 1001,1002);
System.out.println(map);
}
@Test
public void test5(){
String sql = "select * from emp";
List<Map<String, Object>> list = template.queryForList(sql);
for (Map<String, Object> stringObjectMap : list) {
System.out.println(stringObjectMap);
}
}
@Test
public void test6(){
String sql = "select * from emp";
List<Emp> list = template.query(sql, new RowMapper<Emp>() {
@Override
public Emp mapRow(ResultSet rs, int i) throws SQLException {
Emp emp = new Emp();
int id = rs.getInt("id");
String ename = rs.getString("ename");
int job_id = rs.getInt("job_id");
int mgr = rs.getInt("mgr");
Date joindate = rs.getDate("joindate");
double salary = rs.getDouble("salary");
double bonus = rs.getDouble("bonus");
int dept_id = rs.getInt("dept_id");
emp.setId(id);
emp.setEname(ename);
emp.setJob_id(job_id);
emp.setMgr(mgr);
emp.setJoindate(joindate);
emp.setSalary(salary);
emp.setBonus(bonus);
emp.setDept_id(dept_id);
return emp;
}
});
for (Emp emp : list) {
System.out.println(emp);
}
}
@Test
public void test6_2(){
String sql = "select * from emp";
List<Emp> list = template.query(sql, new BeanPropertyRowMapper<Emp>(Emp.class));
for (Emp emp : list) {
System.out.println(emp);
}
}
@Test
public void test7(){
String sql = "select count(id) from emp";
Long total = template.queryForObject(sql, Long.class);
System.out.println(total);
}
}
|
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| import java.sql.Date;
public class Emp {
private Integer id;
private String ename;
private Integer job_id;
private Integer mgr;
private Date joindate;
private Double salary;
private Double bonus;
private Integer dept_id;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public Integer getJob_id() {
return job_id;
}
public void setJob_id(Integer job_id) {
this.job_id = job_id;
}
public Integer getMgr() {
return mgr;
}
public void setMgr(Integer mgr) {
this.mgr = mgr;
}
public Date getJoindate() {
return joindate;
}
public void setJoindate(Date joindate) {
this.joindate = joindate;
}
public Double getSalary() {
return salary;
}
public void setSalary(Double salary) {
this.salary = salary;
}
public Double getBonus() {
return bonus;
}
public void setBonus(Double bonus) {
this.bonus = bonus;
}
public Integer getDept_id() {
return dept_id;
}
public void setDept_id(Integer dept_id) {
this.dept_id = dept_id;
}
@Override
public String toString() {
return "Emp{" +
"id=" + id +
", ename='" + ename + '\'' +
", job_id=" + job_id +
", mgr=" + mgr +
", joindate=" + joindate +
", salary=" + salary +
", bonus=" + bonus +
", dept_id=" + dept_id +
'}';
}
}
|
