将xml檔案讀取成java對象

1.準備xml檔案

我是将xml檔案放在resources下面的

以下是xml檔案的内容，我截取了一部分

<?xml version="1.0" encoding="UTF-8"?>
<c c1="0">
<d d1="101280101" d2="廣州" d3="guangzhou" d4="廣東"/>
<d d1="101280102" d2="番禺" d3="panyu" d4="廣東"/>
<d d1="101280103" d2="從化" d3="conghua" d4="廣東"/>
<d d1="101280104" d2="增城" d3="zengcheng" d4="廣東"/>
<d d1="101280105" d2="花都" d3="huadu" d4="廣東"/>
<d d1="101280201" d2="韶關" d3="shaoguan" d4="廣東"/>
</c>
           

2.準備實體類City 和CityList

下面是City的代碼

package com.example.weather.vo;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "d")
@XmlAccessorType(XmlAccessType.FIELD)
public class City {
    @XmlAttribute(name = "d1")
    private String cityId;
    @XmlAttribute(name = "d2")
    private String cityName;
    @XmlAttribute(name = "d3")
    private String cityCode;
    @XmlAttribute(name = "d4")
    private String province;
    public String getCityId() {
        return cityId;
    }
    public void setCityId(String cityId) {
        this.cityId = cityId;
    }
    public String getCityName() {
        return cityName;
    }
    public void setCityName(String cityName) {
        this.cityName = cityName;
    }
    public String getCityCode() {
        return cityCode;
    }
    public void setCityCode(String cityCode) {
        this.cityCode = cityCode;
    }
    public String getProvince() {
        return province;
    }
    public void setProvince(String province) {
        this.province = province;
    }
}
           

下面是CityList的代碼

package com.example.weather.vo;

import javax.xml.bind.annotation.*;
import java.util.List;

@XmlRootElement(name = "c")
@XmlAccessorType(XmlAccessType.FIELD)
public class CityList {
    @XmlElement(name = "d")
    private List<City> cityList;
    public List<City> getCityList(){
        return cityList;
    }
    public void setCityList(List<City> cityList){
        this.cityList = cityList;
    }
}
           

3.建立工具類XmlBuilder

以下是 XmlBuilder 的代碼

package com.example.weather.util;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import java.io.Reader;
import java.io.StringReader;

public class XmlBuilder {
    public static Object xmlStrToObject(Class<?> clazz, String xmlStr) throws Exception{
     Object xmlObject = null;
     Reader reader = null;
     JAXBContext context = JAXBContext.newInstance(clazz);
     Unmarshaller unmarshaller = context.createUnmarshaller();
     reader = new StringReader(xmlStr);
     xmlObject = unmarshaller.unmarshal(reader);
     return xmlObject;
    }
}
           

4.在對應的 service 調用

以下是 CityDataServiceImpl 代碼

package com.example.weather.service.impl;

import com.example.weather.service.CityDataService;
import com.example.weather.util.XmlBuilder;
import com.example.weather.vo.City;
import com.example.weather.vo.CityList;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Service;

import javax.xml.ws.ServiceMode;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.List;

@Service
public class CityDataServiceImpl implements CityDataService {
    @Override
    public List<City> listCity() throws Exception {
        //讀取XML檔案
        Resource resource = new ClassPathResource("citylist.xml");
        BufferedReader bf = new BufferedReader(new InputStreamReader(resource.getInputStream(), StandardCharsets.UTF_8));
        StringBuilder builder = new StringBuilder();
        String line = "";
        while((line = bf.readLine()) != null){
            builder.append(line);
        }
        bf.close();
        //XML轉為java對象
        CityList cityList = (CityList)XmlBuilder.xmlStrToObject(CityList.class, builder.toString());
        return cityList.getCityList();
    }
}
           

5.controller我就不上代碼了，我用的thymeleaf做模闆引擎，效果如下