<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>kr.or.connect</groupId>
<artifactId>webapiexam</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>webapiexam Maven Webapp</name>
<url>http://maven.apache.org</url>
<properties>
<!-- web.xml 파일을 삭제해도 eclipse에서 오류가 발생하지 않는다. -->
<failOnMissingWebXml>false</failOnMissingWebXml>
</properties>
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.22</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.4</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>webapiexam</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
package kr.or.connect.jdbcexam.dto;
public class Role {
private Integer roleId;
private String description;
public Role() {
}
public Role(Integer roleId, String description) {
super();
this.roleId = roleId;
this.description = description;
}
public Integer getRoleId() {
return roleId;
}
public void setRoleId(Integer roleId) {
this.roleId = roleId;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public String toString() {
return "Role [roleId=" + roleId + ", description=" + description + "]";
}
}
package kr.or.connect.jdbcexam.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import kr.or.connect.jdbcexam.dto.Role;
public class RoleDao {
private static String dburl = "jdbc:mysql://localhost:3306/connectdb?serverTimezone=UTC";
private static String dbUser = "connectuser";
private static String dbpasswd = "PASSWORD";
public List<Role> getRoles(){
List<Role> list = new ArrayList<Role>();
try {
Class.forName("com.mysql.cj.jdbc.Driver");
} catch(ClassNotFoundException e) {
e.printStackTrace();
}
String sql = "SELECT description, role_id FROM role order by role_id desc";
// try with resource - finally에서 close를 생략할 수 있는 방법
try (Connection conn = DriverManager.getConnection(dburl, dbUser, dbpasswd);
PreparedStatement ps = conn.prepareStatement(sql)){
try(ResultSet rs = ps.executeQuery()){
while (rs.next()) {
String description = rs.getString(1);
int id = rs.getInt("role_id");
Role role = new Role(id, description);
list.add(role);
}
} catch(Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
}
package kr.or.connect.webapiexam.api;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
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 com.fasterxml.jackson.databind.ObjectMapper;
import kr.or.connect.jdbcexam.dao.RoleDao;
import kr.or.connect.jdbcexam.dto.Role;
@WebServlet("/roles")
public class RolesServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public RolesServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
response.setContentType("application/json");
RoleDao dao = new RoleDao();
List<Role> list = dao.getRoles();
/* jackson-databind 라이브러리가 제공하는 ObjectMapper 객체 사용
* 객체를 JSON 문자열로 바꾸거나, JSON 문자열을 객체로 바꾸는 역할
*/
ObjectMapper objectMapper = new ObjectMapper();
/* writeValueAsString 메서드는 list를 JSON 문자열로 바뀌게 해준다.
*/
String json = objectMapper.writeValueAsString(list);
System.out.println(json);
PrintWriter out = response.getWriter();
out.println(json);
out.close();
}
}
결과