第1 章　Java 語(yǔ)言基礎(chǔ)

1.1　Java 語(yǔ)言介紹 ....................................................................................................1

1.1.1　Java 語(yǔ)言的發(fā)展歷程 .........................................................................................1

1.1.2　Java 語(yǔ)言的體系 .................................................................................................2

1.1.3　Java 語(yǔ)言的特點(diǎn) .................................................................................................2

1.1.4　Java 語(yǔ)言的地位 .................................................................................................3

1.2　搭建Java 開(kāi)發(fā)環(huán)境 ...........................................................................................3

1.2.1　安裝JDK .............................................................................................................3

1.2.2　在Windows 7 配置Java 環(huán)境 ............................................................................6

1.2.3　在Windows 10 配置Java 環(huán)境 ..........................................................................6

1.2.4　充分利用Java API 文檔 .....................................................................................8

1.3　第一個(gè)Java 程序 ...............................................................................................9

1.3.1　編寫(xiě)第一個(gè)Java 代碼 ........................................................................................9

實(shí)例1-1：第一個(gè)Java 程序代碼 ................................................................................................ 9

1.3.2　編譯Java 程序 ....................................................................................................9

1.3.3　運(yùn)行Java 代碼 ..................................................................................................10

1.3.4　Java 11 新特性：新的程序運(yùn)行方式 .............................................................11

第２章　使用IDE 開(kāi)發(fā)工具

2.1　使用Eclipse .....................................................................................................12

2.1.1　IDE 介紹 ...........................................................................................................12

2.1.2　下載并安裝Eclipse ..........................................................................................12

2.1.3　新建一個(gè)Eclipse 項(xiàng)目 .....................................................................................16

2.1.4　編譯并運(yùn)行Eclipse 項(xiàng)目 .................................................................................17

2.1.5　使用Eclipse 打開(kāi)一個(gè)Java 工程打開(kāi)下載包中的項(xiàng)目 ........................18

2.2　使用Intellij IDEA ............................................................................................19

2.2.1　搭建IntelliJ IDEA 開(kāi)發(fā)環(huán)境 ...........................................................................19

2.2.2　使用IntelliJ IDEA 新建Java 工程 ..................................................................21

2.2.3　使用IntelliJ IDEA 運(yùn)行Java 程序 ..................................................................22

第3 章　Java 基礎(chǔ)語(yǔ)法

3.1　關(guān)鍵字、標(biāo)識(shí)符和注釋 ..................................................................................23

3.1.1　關(guān)鍵字 ...............................................................................................................23

3.1.2　標(biāo)識(shí)符 ...............................................................................................................24

3.1.3　注釋 ...................................................................................................................24

3.2　變量和常量 ......................................................................................................25

3.2.1　常量 ...................................................................................................................25

實(shí)例3-1：定義幾個(gè)Java 常量 .................................................................................................. 25

3.2.2　變量 ...................................................................................................................26

實(shí)例3-2：計(jì)算三角形、正方形和長(zhǎng)方形的面積 ................................................................... 27

實(shí)例3-3：輸出各種變量的值 ................................................................................................... 27

3.3　數(shù)據(jù)類(lèi)型 ..........................................................................................................28

3.3.1　為什么引入數(shù)據(jù)類(lèi)型 .......................................................................................29

3.3.2　基本數(shù)據(jù)類(lèi)型的取值范圍 ...............................................................................29

3.3.3　字符型 ...............................................................................................................30

實(shí)例3-4：輸出三種特殊符號(hào) ................................................................................................... 30

3.3.4　整型 ...................................................................................................................31

實(shí)例3-5：通過(guò)整型類(lèi)型計(jì)算圖形周長(zhǎng)和面積 ....................................................................... 31

3.3.5　浮點(diǎn)型 ...............................................................................................................32

實(shí)例3-6：計(jì)算圓的面積 ........................................................................................................... 33

3.3.6　布爾型 ...............................................................................................................33

實(shí)例3-7：比較兩個(gè)數(shù)的大小 ................................................................................................... 33

3.4　運(yùn)算符 ..............................................................................................................34

3.4.1　算術(shù)運(yùn)算符 .......................................................................................................34

實(shí)例3-8：基本的數(shù)學(xué)運(yùn)算（加、減、乘、除） ................................................................... 34

實(shí)例3-9：使用%運(yùn)算符 .................................................................................................... 35

實(shí)例3-10：使用遞增與遞減運(yùn)算符 ......................................................................................... 36

3.4.2　關(guān)系運(yùn)算符和邏輯運(yùn)算符 ...............................................................................36

實(shí)例3-11：使用關(guān)系運(yùn)算符比較數(shù)字和字符 ......................................................................... 37

3.4.3　位運(yùn)算符 ...........................................................................................................38

實(shí)例3-12：對(duì)兩個(gè)整數(shù)實(shí)現(xiàn)位運(yùn)算 ......................................................................................... 39

3.4.4　條件運(yùn)算符 .......................................................................................................39

實(shí)例3-13：使用條件運(yùn)算符判斷成績(jī)是否優(yōu)秀 ..................................................................... 39

3.4.5　賦值運(yùn)算符 .......................................................................................................40

實(shí)例3-14：賦值類(lèi)型不匹配的錯(cuò)誤 ......................................................................................... 40

3.4.6　運(yùn)算符的優(yōu)先級(jí) ...............................................................................................40

實(shí)例3-15：四則混合運(yùn)算 ......................................................................................................... 41

3.5　類(lèi)型轉(zhuǎn)換 ..........................................................................................................42

3.5.1　自動(dòng)類(lèi)型轉(zhuǎn)換 ...................................................................................................42

實(shí)例3-16：將整數(shù)自動(dòng)轉(zhuǎn)換為fl oat 類(lèi)型 ................................................................................ 42

3.5.2　強(qiáng)制轉(zhuǎn)換 ...........................................................................................................43

實(shí)例3-17：實(shí)現(xiàn)int、byte 和double 類(lèi)型之間的強(qiáng)制轉(zhuǎn)換 ................................................... 43

第4 章　使用條件語(yǔ)句

4.1　使用if 語(yǔ)句 ......................................................................................................44

4.1.1　if 語(yǔ)句介紹 ........................................................................................................44

實(shí)例4-1：判斷成績(jī)是否及格 ................................................................................................... 45

4.1.2　if 語(yǔ)句的延伸 ....................................................................................................45

實(shí)例4-2：對(duì)兩種條件給出不同的答案 ................................................................................... 46

4.1.3　多個(gè)條件判斷的if 語(yǔ)句 ...................................................................................46

實(shí)例4-3：模擬抽獎(jiǎng)系統(tǒng) ........................................................................................................... 47

4.2　使用switch 語(yǔ)句 ..............................................................................................47

4.2.1　switch 語(yǔ)句基礎(chǔ) ................................................................................................48

實(shí)例4-4：判斷數(shù)字的大小 ....................................................................................................... 48

4.2.2　沒(méi)有break 時(shí)的情形 ........................................................................................49

實(shí)例4-5：執(zhí)行switch 后面的所有分支條件語(yǔ)句 ................................................................... 49

4.2.3　case 沒(méi)有執(zhí)行語(yǔ)句 ...........................................................................................49

實(shí)例4-6：在case 語(yǔ)句后沒(méi)有執(zhí)行的代碼 .............................................................................. 50

4.2.4　default 可以不在末尾 .......................................................................................50

實(shí)例4-7：將default 放在第一個(gè)case 分支中 ......................................................................... 50

第5 章　使用循環(huán)語(yǔ)句

5.1　使用for 循環(huán)語(yǔ)句 ............................................................................................51

5.1.1　for 循環(huán)介紹 .....................................................................................................51

實(shí)例5-1：輸出整數(shù)0 到9 ........................................................................................................ 52

5.1.2　嵌套使用for 循環(huán) ............................................................................................52

實(shí)例5-2：使用嵌套for 語(yǔ)句顯示人民幣符號(hào)和美元符號(hào) ..................................................... 53

實(shí)例5-3：在屏幕中輸出一個(gè)用*擺放的菱形 ................................................................. 53

5.2　使用while 循環(huán)語(yǔ)句 .......................................................................................54

5.2.1　while 循環(huán)基礎(chǔ) .................................................................................................54

實(shí)例5-4：循環(huán)輸出18 個(gè)數(shù)字 ................................................................................................. 54

實(shí)例5-5：輸出能夠整除7 的數(shù)字 ........................................................................................... 55

5.2.2　do-while 循環(huán)語(yǔ)句 ............................................................................................55

實(shí)例5-6：使用do-while 語(yǔ)句輸出0 到7 ................................................................................ 56

實(shí)例5-7：計(jì)算1 2 3 …. 100 的和 ....................................................................................... 56

5.3　使用跳轉(zhuǎn)語(yǔ)句 ..................................................................................................57

5.3.1　break 語(yǔ)句 .........................................................................................................57

實(shí)例5-8：使用break 終止循環(huán)的執(zhí)行 .................................................................................... 57

實(shí)例5-9：在while 循環(huán)語(yǔ)句中使用break............................................................................... 57

實(shí)例5-10：使用有標(biāo)號(hào)的break 語(yǔ)句 ...................................................................................... 58

5.3.2　使用return 語(yǔ)句 ...............................................................................................59

實(shí)例5-11：使用return 語(yǔ)句結(jié)束循環(huán)的執(zhí)行 .......................................................................... 59

5.3.3　使用continue 跳轉(zhuǎn)語(yǔ)句 ...................................................................................59

實(shí)例5-12：使用continue 改變for 循環(huán)的運(yùn)行結(jié)果 ............................................................... 59

第6 章　操作字符串

6.1　Java 字符串的初始化 ......................................................................................61

實(shí)例6-1：實(shí)現(xiàn)Java 字符串的初始化 ...................................................................................... 61

6.2　使用String 類(lèi)操作字符串 ..............................................................................62

6.2.1　獲取指定索引位置的字符 ...............................................................................62

實(shí)例6-2：返回某個(gè)字符串指定索引的字符 ........................................................................... 62

6.2.2　追加字符串 .......................................................................................................63

實(shí)例6-3：在字符串后面追加字符串（好好 學(xué)習(xí)） ........................................................... 63

6.2.3　連接多個(gè)字符串 ...............................................................................................63

實(shí)例6-4：使用 連接兩個(gè)對(duì)象 ......................................................................................... 63

6.2.4　比較字符串 .......................................................................................................63

實(shí)例6-5：判斷兩個(gè)指定的字符串是否相等 ........................................................................... 64

6.2.5　獲得字符串長(zhǎng)度 ...............................................................................................64

實(shí)例6-6：獲取字符串的長(zhǎng)度 ................................................................................................... 64

6.2.6　替換字符串 .......................................................................................................65

實(shí)例6-7：替換字符串中的某一個(gè)文字 ................................................................................... 65

6.2.7　截取字符串 .......................................................................................................65

實(shí)例6-8：截取一個(gè)字符串，并輸出截取后的結(jié)果 ............................................................... 65

6.2.8　字符串的大小寫(xiě)互轉(zhuǎn) .......................................................................................66

實(shí)例6-9：對(duì)指定的字符串實(shí)現(xiàn)大小寫(xiě)轉(zhuǎn)換 ........................................................................... 66

6.2.9　消除字符串中的空白字符 ...............................................................................66

實(shí)例6-10：去掉字符串開(kāi)頭的空白字符 ................................................................................. 66

6.2.10　查找字符串 .....................................................................................................67

實(shí)例6-11：查找字符串str 中空字符的位置 ........................................................................... 68

6.3　使用類(lèi)StringBuffer ........................................................................................68

實(shí)例6-12：使用追加字符函數(shù) ................................................................................................. 69

第7 章　使用數(shù)組

7.1　最簡(jiǎn)單的一維數(shù)組 ..........................................................................................70

7.1.1　聲明一維數(shù)組 ...................................................................................................70

7.1.2　創(chuàng)建一維數(shù)組 ...................................................................................................70

實(shí)例7-1：創(chuàng)建并輸出一維數(shù)組中的數(shù)據(jù) ............................................................................... 71

7.1.3　初始化一維數(shù)組 ...............................................................................................72

實(shí)例7-2：初始化一維數(shù)組，并將數(shù)組值輸出打印 ............................................................... 72

7.2　二維數(shù)組 ..........................................................................................................73

7.2.1　聲明二維數(shù)組 ...................................................................................................73

7.2.2　創(chuàng)建二維數(shù)組 ...................................................................................................73

實(shí)例7-3：創(chuàng)建二維數(shù)組并輸出打印里面的數(shù)據(jù) ................................................................... 74

7.2.3　初始化二維數(shù)組 ...............................................................................................74

實(shí)例7-4：打印輸出二維數(shù)組中的數(shù)據(jù) ................................................................................... 75

7.3　三維數(shù)組 ..........................................................................................................76

7.3.1　聲明三維數(shù)組 ...................................................................................................76

7.3.2　初始化三維數(shù)組 ...............................................................................................76

實(shí)例7-5：創(chuàng)建三維數(shù)組，然后輸出打印數(shù)組內(nèi)元素 ........................................................... 77

7.4　操作數(shù)組 ..........................................................................................................77

7.4.1　復(fù)制數(shù)組 ...........................................................................................................78

實(shí)例7-6：復(fù)制一維數(shù)組中的元素 ........................................................................................... 78

7.4.2　比較數(shù)組 ...........................................................................................................79

實(shí)例7-7：比較兩個(gè)一維數(shù)組 ................................................................................................... 79

7.4.3　搜索數(shù)組中的元素 ...........................................................................................79

實(shí)例7-8：使用binarySearch() 搜索數(shù)組內(nèi)元素...................................................................... 79

7.4.4　排序數(shù)組 ...........................................................................................................80

實(shí)例7-9：使用sort() 排序數(shù)組內(nèi)元素 ..................................................................................... 80

7.4.5　填充數(shù)組 ...........................................................................................................80

實(shí)例7-10：使用fi ll() 向數(shù)組中添加新的元素 ........................................................................ 80

7.5　數(shù)組的高級(jí)用法 ..............................................................................................81

7.5.1　動(dòng)態(tài)數(shù)組 ...........................................................................................................81

實(shí)例7-11：將ArrayList 作為Java 動(dòng)態(tài)數(shù)組 ........................................................................... 82

7.5.2　使用foreach 循環(huán) .............................................................................................82

實(shí)例7-12：使用foreach 遍歷輸出數(shù)組中的元素 ................................................................... 83

7.5.3　數(shù)組和內(nèi)存 .......................................................................................................83

實(shí)例7-13：初始化基本類(lèi)型數(shù)組 ............................................................................................. 84