java接口开发入门示例

最近在测试中发现mysql数据库保存测试用例，测试结果是一种不错的选择，为了后期方便在客户端展示测试，便写了个接口。此次接口开发不使用任何框架，需下载gson.jar，mysql-connector.jar，servlet-api.jar，以下为接口的开发思路

1.创建数据表，我这边使用的是mysql数据库

/*
SQLyog 企业版 - MySQL GUI v8.14 
MySQL - 5.5.49 : Database - test
*********************************************************************
*/


/*!40101 SET NAMES utf8 */;

/*!40101 SET SQL_MODE=''*/;

/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`test` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `test`;

/*Table structure for table `testcase` */

DROP TABLE IF EXISTS `testcase`;

CREATE TABLE `testcase` (
  `caseId` INT(11) NOT NULL AUTO_INCREMENT,
  `caseName` VARCHAR(255) CHARACTER SET latin1 NOT NULL,
  `caseDetail` VARCHAR(255) CHARACTER SET latin1 NOT NULL,
  `caseDevice` VARCHAR(255) CHARACTER SET latin1 NOT NULL,
  PRIMARY KEY (`caseId`)
) ENGINE=INNODB AUTO_INCREMENT=48 DEFAULT CHARSET=utf8 CHECKSUM=1 DELAY_KEY_WRITE=1 ROW_FORMAT=DYNAMIC;

/*Data for the table `testcase` */

INSERT  INTO `testcase`(`caseId`,`caseName`,`caseDetail`,`caseDevice`) VALUES (2,'2','233','444'),(16,'dsf','sf','sfd'),(17,'safd','sadf','asf'),(18,'saf','ggd','sdf'),(19,'dsaf','sdf','sdf'),(20,'sfd','sfd','(NfdsULL)'),(21,'sdf','v','v'),(22,'f','f','e'),(23,'w','r3','rt'),(24,'er','rtrt','sfad'),(25,'sf','sdf','fds'),(26,'sa','s','s'),(27,'e','e','e'),(28,'sa','rt','rt'),(29,'we','ew','qw'),(30,'we','(NULfL)','dsf'),(31,'fd','s','g'),(32,'s','g','f'),(33,'sf','f','f'),(34,'c','c','c'),(35,'e','e','e'),(36,'d','d','q'),(37,'q','e','r'),(38,'f','r','g'),(39,'g','(NULgL)','g'),(40,'gg','g','d'),(41,'f','f','f'),(42,'f','f','f'),(43,'f','f','f'),(44,'v','f','g'),(45,'e','e','r'),(46,'4','rt','fg'),(47,'dsf','ds','sdf');

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

2.编写数据库工具类

package model;

import java.sql.*;

public class DBconn {
    static String url = "jdbc:mysql://localhost:3306/test?useunicuee=true& characterEncoding=utf8"; 
    static String username = "root"; 
    static String password = "123456"; 
    static Connection  conn = null;
    static ResultSet rs = null;
    static PreparedStatement ps =null;
    public static void init(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(url,username,password);
        } catch (Exception e) {
            System.out.println("init [SQL驱动程序初始化失败！]");
            e.printStackTrace();
        }
    }
    public static int addUpdDel(String sql){
        int i = 0;
        try {
            PreparedStatement ps =  conn.prepareStatement(sql);
            i =  ps.executeUpdate();
        } catch (SQLException e) {
            System.out.println("sql数据库增删改异常");
            e.printStackTrace();
        }
        
        return i;
    }
    public static ResultSet selectSql(String sql){
        try {
            ps =  conn.prepareStatement(sql);
            rs =  ps.executeQuery(sql);
        } catch (SQLException e) {
            System.out.println("sql数据库查询异常");
            e.printStackTrace();
        }
        return rs;
    }
    public static void closeConn(){
        try {
            conn.close();
        } catch (SQLException e) {
            System.out.println("sql数据库关闭异常");
            e.printStackTrace();
        }
    }
}

3.编写实体类

package model;

public class TestCase {
     private int id;
     private String caseName;
     private String caseDetail;
     private String caseDevice;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getCaseName() {
        return caseName;
    }
    public void setCaseName(String caseName) {
        this.caseName = caseName;
    }
    public String getCaseDetail() {
        return caseDetail;
    }
    public void setCaseDetail(String caseDetail) {
        this.caseDetail = caseDetail;
    }
    public String getCaseDevice() {
        return caseDevice;
    }
    public void setCaseDevice(String caseDevice) {
        this.caseDevice = caseDevice;
    }
     
}

4.新建一个分页实体类，以便后期数据做分页

package model;

import java.util.List;

public class TestCaseTotal {
    private int total; 
    private List<TestCase> rows; 
    
    
    public TestCaseTotal() {
    }
    public TestCaseTotal(int total, List<TestCase> rows) {
        this.total = total;
        this.rows = rows;
    }
    public int getTotal() {
        return total;
    }
    public void setTotal(int total) {
        this.total = total;
    }
    public List<TestCase> getRows() {
        return rows;
    }
    public void setRows(List<TestCase> rows) {
        this.rows = rows;
    }
    
}

5.基础操作写到一个接口里

package model;

import java.util.List;


public interface TestCaseDao {
    public List<TestCase> getCaseAll();
    public boolean addCase(TestCase testCase) ;
    public boolean deleteCase(int id) ;
    public boolean updateCase(TestCase testCase) ;

}

6.实现Dao接口

package model;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;



public class TestCaseDaoImpl implements TestCaseDao {
    private PreparedStatement ptmt = null;  
    private ResultSet rs = null;
    @Override
    public List<TestCase> getCaseAll() {
        // TODO Auto-generated method stub
        List<TestCase> list = new ArrayList<TestCase>();
        try {
            DBconn.init();
            ResultSet rs = DBconn.selectSql("select * from testcase");
            while(rs.next()){
                TestCase testCase=new TestCase();
                testCase.setId(rs.getInt("caseId"));
                testCase.setCaseName(rs.getString("caseName"));
                testCase.setCaseDetail(rs.getString("caseDetail"));
                testCase.setCaseDevice(rs.getString("caseDevice"));
                
                list.add(testCase);
            }
            DBconn.closeConn();
            return list;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
        
    }

    @Override
    public boolean addCase(TestCase testCase) {
        // TODO Auto-generated method stub
        boolean flag = false;
        DBconn.init();
        int i =DBconn.addUpdDel("insert into user(caseName,caseDetail,caseDevice) " +
                "values('"+testCase.getCaseName()+"','"+testCase.getCaseDetail()+"','"+testCase.getCaseDevice()+"')");
        if(i>0){
            flag = true;
        }
        DBconn.closeConn();
        return flag;
    }

    @Override
    public boolean deleteCase(int id) {
        // TODO Auto-generated method stub
        boolean flag = false;
        DBconn.init();
        String sql = "delete from testcase where caseId="+id;
        
        
        int i =DBconn.addUpdDel(sql);
        if(i>0){
            flag = true;
        }
        DBconn.closeConn();
        return flag;
    

    }

    @Override
    public boolean updateCase(TestCase testCase) {
        // TODO Auto-generated method stub
        return false;
    }

}

7.新建JsonServlet

package model;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.gson.Gson;



public class JsonServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
        
        TestCaseDaoImpl testCaseDaoImpl=new TestCaseDaoImpl();
        List<TestCase> list=testCaseDaoImpl.getCaseAll();
        List<TestCase> list1 =new ArrayList<>();
        int size =list.size();
        TestCase testCase;
        for(int i=0;i<size;i++){
            testCase=new TestCase();
            testCase.setId(list.get(i).getId());
            testCase.setCaseName(list.get(i).getCaseName());
            testCase.setCaseDetail(list.get(i).getCaseDetail());
            list1.add(testCase);
            
        }
        
        String page = req.getParameter("page");
        // 将数据添加到数组
        List<TestCase> caselist = new ArrayList<TestCase>();
        
        //以下代码做分页，写的不好，不喜勿喷
        if (page == null || page.equals("0")) {
            if(list1.size()>9){
                for(int i=0;i<10;i++){
                    caselist.add(list1.get(i));
                }
            }
            else{
                for(int i=0;i<list1.size();i++){
                    caselist.add(list1.get(i));
                }
            }
            
        }
        else {
            int caseSize=list1.size();
            int page1 =caseSize/10;
            
            int pageNum=Integer.parseInt(page);
            //String parm=Integer.toString(a);
            if(pageNum<page1){
                for(int i=10*pageNum;i<10*pageNum+10;i++){
                    caselist.add(list1.get(i));
                }
            }
            else{
                for(int i=10*pageNum;i<list1.size();i++){
                    caselist.add(list1.get(i));
                }
            }
            
        }

        
        TestCaseTotal nt = new TestCaseTotal(caselist.size(), caselist);

        // 调用GSON jar工具包封装好的toJson方法，可直接生成JSON字符串
        Gson gson = new Gson();
        String json = gson.toJson(nt);

        // 输出到界面
        System.out.println(json);
        resp.setContentType("text/plain");
        resp.setCharacterEncoding("gb2312");
        PrintWriter out = new PrintWriter(resp.getOutputStream());
        out.print(json);
        out.flush();
        
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req, resp);
    }

}

8.新建index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
     <base href="<%=basePath%>">
    
    <title>Test Json1</title>
    
    
    <meta http-equiv="Content-Type" content="text/html"; charset=UTF-8>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    
    
  </head>
  <body >
  <form action="getJson" method="get">
        <input type="submit" value="点击获取测试用例数据"/>
     </form>
  </body>
</html>

9.修改web.xml文件如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>JsonTest</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
      <servlet-name>JsonServlet</servlet-name>
      <servlet-class>model.JsonServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>JsonServlet</servlet-name>
      <url-pattern>/getJson</url-pattern>
  </servlet-mapping>
</web-app>

10.右击项目名-->选择Run as-->选择Run on Server

11.运行成功后如下：

每页只展示10条数据，若需要查看第二页数据传入参数page =1即可