jdbctemplate的使用

最新推荐文章于 2023-12-01 08:04:09 发布

iteye_15968

最新推荐文章于 2023-12-01 08:04:09 发布

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在使用JdbcTemplate之前记得要在spring中定义一个datasource的bean(即注入datasource),并且实现jdbcdaosupport接口(我们通常使用的事务管理叫做编程式事务管理（还有一个叫声明式事务管理）)
jdbcTemplate.execute("CREATETABLEUSER(user_idinteger,namevarchar(100))");

jdbcTemplate.execute("CREATE TABLE USER (user_id integer, name varchar(100))");

2、如果是UPDATE或INSERT,可以用update()方法。

jdbcTemplate.update("INSERTINTOUSERVALUES('"
+user.getId()+"','"
+user.getName()+"','"
+user.getSex()+"','"
+user.getAge()+"')");

jdbcTemplate.update("INSERT INTO USER VALUES('"
           + user.getId() + "', '"
           + user.getName() + "', '"
           + user.getSex() + "', '"
           + user.getAge() + "')");

3、带参数的更新

jdbcTemplate.update("UPDATEUSERSETname=?WHEREuser_id=?",newObject[]{name,id});

jdbcTemplate.update("UPDATE USER SET name = ? WHERE user_id = ?", new Object[] {name, id});

jdbcTemplate.update("INSERTINTOUSERVALUES(?,?,?,?)",newObject[]{user.getId(),user.getName(),user.getSex(),user.getAge()});

jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)", new Object[] {user.getId(), user.getName(), user.getSex(), user.getAge()});

4、使用JdbcTemplate进行查询时，使用queryForXXX()等方法

intcount=jdbcTemplate.queryForInt("SELECTCOUNT(*)FROMUSER");

int count = jdbcTemplate.queryForInt("SELECT COUNT(*) FROM USER");

Stringname=(String)jdbcTemplate.queryForObject("SELECTnameFROMUSERWHEREuser_id=?",newObject[]{id},java.lang.String.class);

String name = (String) jdbcTemplate.queryForObject("SELECT name FROM USER WHERE user_id = ?", new Object[] {id}, java.lang.String.class);

Listrows=jdbcTemplate.queryForList("SELECT*FROMUSER");

List rows = jdbcTemplate.queryForList("SELECT * FROM USER");

Listrows=jdbcTemplate.queryForList("SELECT*FROMUSER");
Iteratorit=rows.iterator();
while(it.hasNext()){
MapuserMap=(Map)it.next();
System.out.print(userMap.get("user_id")+"\t");
System.out.print(userMap.get("name")+"\t");
System.out.print(userMap.get("sex")+"\t");
System.out.println(userMap.get("age")+"\t");
}

List rows = jdbcTemplate.queryForList("SELECT * FROM USER");
Iterator it = rows.iterator();
while(it.hasNext()) {
    Map userMap = (Map) it.next();
    System.out.print(userMap.get("user_id") + "\t");
    System.out.print(userMap.get("name") + "\t");
    System.out.print(userMap.get("sex") + "\t");
    System.out.println(userMap.get("age") + "\t");
}

JdbcTemplate将我们使用的JDBC的流程封装起来，包括了异常的捕捉、SQL的执行、查询结果的转换等等。spring大量使用Template Method模式来封装固定流程的动作，XXXTemplate等类别都是基于这种方式的实现。
除了大量使用Template Method来封装一些底层的操作细节，Spring也大量使用callback方式类回调相关类别的方法以提供JDBC相关类别的功能，使传统的JDBC的使用者也能清楚了解spring所提供的相关封装类别方法的使用。

JDBC的PreparedStatement

finalStringid=user.getId();
finalStringname=user.getName();
finalStringsex=user.getSex()+"";
finalintage=user.getAge();
jdbcTemplate.update("INSERTINTOUSERVALUES(?,?,?,?)",
newPreparedStatementSetter(){
publicvoidsetValues(PreparedStatementps)throwsSQLException{
ps.setString(1,id);
ps.setString(2,name);
ps.setString(3,sex);
ps.setInt(4,age);
}
});

final String id = user.getId();
final String name = user.getName();
final String sex = user.getSex() + "";
final int age = user.getAge();

jdbcTemplate.update("INSERT INTO USER VALUES(?, ?, ?, ?)",
                     new PreparedStatementSetter() {
                         public void setValues(PreparedStatement ps) throws SQLException {
                             ps.setString(1, id);
                             ps.setString(2, name);          
                             ps.setString(3, sex);
                             ps.setInt(4, age);
                         }
                     });

finalUseruser=newUser();
jdbcTemplate.query("SELECT*FROMUSERWHEREuser_id=?",
newObject[]{id},
newRowCallbackHandler(){ //用RowCallbackHandler()对象回调,返回的是void类型
publicvoidprocessRow(ResultSetrs)throwsSQLException{
user.setId(rs.getString("user_id"));
user.setName(rs.getString("name"));
user.setSex(rs.getString("sex").charAt(0));
user.setAge(rs.getInt("age"));
}
});

final User user = new User();
jdbcTemplate.query("SELECT * FROM USER WHERE user_id = ?",
                    new Object[] {id},
                    new RowCallbackHandler() {
                        public void processRow(ResultSet rs) throws SQLException {
                            user.setId(rs.getString("user_id"));
                            user.setName(rs.getString("name"));
                            user.setSex(rs.getString("sex").charAt(0));
                            user.setAge(rs.getInt("age"));
                        }
                    });

classUserRowMapperimplementsRowMapper{
publicObjectmapRow(ResultSetrs,intindex)throwsSQLException{
Useruser=newUser();
user.setId(rs.getString("user_id"));
user.setName(rs.getString("name"));
user.setSex(rs.getString("sex").charAt(0));
user.setAge(rs.getInt("age"));
returnuser;
}
}
publicListfindAllByRowMapperResultReader(){
Stringsql="SELECT*FROMUSER";
returnjdbcTemplate.query(sql,newRowMapperResultReader(newUserRowMapper()));
}

class UserRowMapper implements RowMapper {
    public Object mapRow(ResultSet rs, int index) throws SQLException {//用RowMapper对象回调才是List类型

      User user = new User();

        user.setId(rs.getString("user_id"));
        user.setName(rs.getString("name"));
        user.setSex(rs.getString("sex").charAt(0));
        user.setAge(rs.getInt("age"));

        return user;
    }
}

public List findAllByRowMapperResultReader() {
    String sql = "SELECT * FROM USER";
    return jdbcTemplate.query(sql, new RowMapperResultReader(new UserRowMapper()));
}

在getUser(id)里面使用UserRowMapper

publicUsergetUser(finalStringid)throwsDataAccessException{
Stringsql="SELECT*FROMUSERWHEREuser_id=?";
finalObject[]params=newObject[]{id};
Listlist=jdbcTemplate.query(sql,params,newRowMapperResultReader(newUserRowMapper()));
return(User)list.get(0);
}

public User getUser(final String id) throws DataAccessException {
    String sql = "SELECT * FROM USER WHERE user_id=?";
    final Object[] params = new Object[] { id };
    List list = jdbcTemplate.query(sql, params, new RowMapperResultReader(new UserRowMapper()));

    return (User) list.get(0);
}

网上收集
org.springframework.jdbc.core.PreparedStatementCreator 返回预编译SQL 不能于Object[]一起用

publicPreparedStatementcreatePreparedStatement(Connectioncon)throwsSQLException{
returncon.prepareStatement(sql);
}

 public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
  return con.prepareStatement(sql);
 }

1.增删改
org.springframework.jdbc.core.JdbcTemplate 类(必须指定数据源dataSource)

template.update("insertintoweb_personvalues(?,?,?)",Object[]);

 template.update("insert into web_person values(?,?,?)",Object[]);

或

template.update("insertintoweb_personvalues(?,?,?)",newPreparedStatementSetter(){匿名内部类只能访问外部最终局部变量
publicvoidsetValues(PreparedStatementps)throwsSQLException{
ps.setInt(index++,3);
});

 template.update("insert into web_person values(?,?,?)",new PreparedStatementSetter(){ 匿名内部类 只能访问外部最终局部变量

  public void setValues(PreparedStatement ps) throws SQLException {
   ps.setInt(index++,3);
 });

org.springframework.jdbc.core.PreparedStatementSetter 接口处理预编译SQL

publicvoidsetValues(PreparedStatementps)throwsSQLException{
ps.setInt(index++,3);
}

 public void setValues(PreparedStatement ps) throws SQLException {
  ps.setInt(index++,3);
 }

2.查询JdbcTemplate.query(String,[Object[]/PreparedStatementSetter],RowMapper/RowCallbackHandler)
org.springframework.jdbc.core.RowMapper 记录映射接口处理结果集

publicObjectmapRow(ResultSetrs,intarg1)throwsSQLException{int表当前行数
person.setId(rs.getInt("id"));
}
Listtemplate.query("select*fromweb_personwhereid=?",Object[],RowMapper);

 public Object mapRow(ResultSet rs, int arg1) throws SQLException {   int表当前行数
   person.setId(rs.getInt("id"));
 }
 List template.query("select * from web_person where id=?",Object[],RowMapper);

org.springframework.jdbc.core.RowCallbackHandler 记录回调管理器接口处理结果集

template.query("select*fromweb_personwhereid=?",Object[],newRowCallbackHandler(){
publicvoidprocessRow(ResultSetrs)throwsSQLException{
person.setId(rs.getInt("id"));
});